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BSS_Vidar
08-11-2004, 08:34 PM
Just had a great conversation with a friend of mind who is a PhD in Aviation History and Aeronautical Sciences. I mentioned the lack of performance with the P-51 in regards to holding speed with 109's and 190's. He thought that quite a bit odd. He asked me if I opened the radiator vent. I told'em only during take-off and climb-out to maintain engine cooling, then closed it at higher altitudes.
He told me to test it by opening it when I want to get some speed. What is suppose to happen is:

1. Air goes in the radiator inlet under the belly.
2. Gets super-heated by the engine.
3. Due to expansion from heating in a confined space, the air is hyper expanded and pressurized.
4. Open the radiator exhaust vent in the back
* With the aide of the Venturi Effect, the exiting super-heated air squeeeeeezes out the vent producing up to 15% more thrust.

The Professor said:
"This was one of the most highly kept secrets for the P-51's high-speed performance during WWII."

Test in-game:
Opened the radiator exhast vent at different altitudes... NO CHANGE IN SPEED PERFORMANCE.

S!

BSS_Vidar

BSS_Vidar
08-11-2004, 08:34 PM
Just had a great conversation with a friend of mind who is a PhD in Aviation History and Aeronautical Sciences. I mentioned the lack of performance with the P-51 in regards to holding speed with 109's and 190's. He thought that quite a bit odd. He asked me if I opened the radiator vent. I told'em only during take-off and climb-out to maintain engine cooling, then closed it at higher altitudes.
He told me to test it by opening it when I want to get some speed. What is suppose to happen is:

1. Air goes in the radiator inlet under the belly.
2. Gets super-heated by the engine.
3. Due to expansion from heating in a confined space, the air is hyper expanded and pressurized.
4. Open the radiator exhaust vent in the back
* With the aide of the Venturi Effect, the exiting super-heated air squeeeeeezes out the vent producing up to 15% more thrust.

The Professor said:
"This was one of the most highly kept secrets for the P-51's high-speed performance during WWII."

Test in-game:
Opened the radiator exhast vent at different altitudes... NO CHANGE IN SPEED PERFORMANCE.

S!

BSS_Vidar

Enofinu
08-11-2004, 09:05 PM
what means superheated?? does the air warm up at 1000`C or what you mean? hehe
this has been talked to the end, and Oleg told that: you is wrong, be sure.

ASH at S-MART
08-11-2004, 09:05 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
Just had a great conversation with a friend of mind who is a PhD in Aviation History and Aeronautical Sciences. I mentioned the lack of performance with the P-51 in regards to holding speed with 109's and 190's. He thought that quite a bit odd. He asked me if I opened the radiator vent. I told'em only during take-off and climb-out to maintain engine cooling, then closed it at higher altitudes.
He told me to test it by opening it when I want to get some speed. What is suppose to happen is:

1. Air goes in the radiator inlet under the belly.
2. Gets super-heated by the engine.
3. Due to expansion from heating in a confined space, the air is hyper expanded and pressurized.
4. Open the radiator exhaust vent in the back
* With the aide of the Venturi Effect, the exiting super-heated air squeeeeeezes out the vent producing up to 15% more thrust.

The Professor said:
"This was one of the most highly kept secrets for the P-51's high-speed performance during WWII."

Test in-game:
Opened the radiator exhast vent at different altitudes... NO CHANGE IN SPEED PERFORMANCE.

S!

BSS_Vidar<HR></BLOCKQUOTE>Sky Chimp had a good thread on this awhile back.. Initally SC was under that impression too.. But I think he came across some info or someone posted some stuff that showed otherwise.. as for most highly kept secret.. I find that hard to belive.. The termal Venturi was no big secret, just not may willing to go to all the trouble to build the intake ane exhast to do it.

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WWMaxGunz
08-11-2004, 09:05 PM
Wasn't that exit vent controlled by thermostat automatically?

It is no secret here, has been discussed.


Neal

PlaneEater
08-11-2004, 09:12 PM
Why the heck don't we just contact somebody who actually has a flying P-51 and ask them? It's not like there's only one or two left. :P

I can think of a few off the top of my head:

1) Planes of Fame, Chino, CA
2) Flying Heritage Museum, Everett, WA
3) Experimental Aircraft Association Museum, Oshkosh, WI
4) Olympic Warbird Museum, Olympia, WA
5) RENO

And I KNOW there are more than that, and plenty that are practically stock.

Enofinu
08-11-2004, 09:27 PM
no need to call, cos it is only pilot memory issue which has no weight in here. sorry http://ubbxforums.ubi.com/infopop/emoticons/icon_frown.gif otherwise every story what vet´s says should have same weight..

KGr.HH-Sunburst
08-11-2004, 09:31 PM
FYI the P51 was moddeld with the help from a vet P51 pilot who tested the FM

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Enofinu
08-11-2004, 10:20 PM
yea, and that was not enought for you. still begged for better charasterics for plane after it came out http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

lbhskier37
08-11-2004, 10:28 PM
If this whole thing were the case, you would get the most "thrust" when the radiator flap is almost closed. This would create a nozzle, increasing the velocity of the hot exiting air and increasing the momentum flux. So opening the radiator would give you less of a nozzle, or even a diffuser which would cause the air to exit at a lower velocity therefore giving you lower momentum flux. At least I think thats how it goes, its late here and I dont have my fluid books handy.


Edit: I found the conservation of momentum equation, like I thought I remembered momentum flux ends up depending on the sqaure of velocity, so I think I was right. Anyways, if it was such a great effect, why don't cars or anything for that matter use it nowdays? Good example is F1 cars, their cooling systems produce a tons of heat, but I've never seen the cooling air used like a "jet". And if this was the P51s secret, why would you ever close the radiator(aside from cold starts), did some pilots leave the radiator shut to give the germans a better chance?

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BSS_Vidar
08-11-2004, 11:03 PM
I flew a P-51 here about 3 months ago. It's a dream to fly. The sound file (in-game) is nothing like it. The roll rate in-game on the P-51 is too fast and snappy. Also the FM as flight control inputs and responces that are too strong. I accedently trying to prevent my plane from tipping over due to exccessive taxi speed. Deflecting the aileron stop the tip over. And I couldnt stop chucklin' for a half hour.

In flight, I opened the radiator vent just to see what it would do. The airspedd in a P-51D at 4,500' was 460 kts. (Never see THAT in level flight in-game "without a dive")
There's a lot more issue regarding just plane vs another here, but rather the entire flight model design. Short of CFS2's terrible trim adaptation, it has the most accurate flight model available for that erra. It has its many problems, but the basic flight model is correct.
Putting the PF plane in a FB game,,,?
They'ld get eatin alive.

BSS_Vidar

BSS_Vidar
08-11-2004, 11:15 PM
The Ventury effect I mentioned was more cridicle with the radiator vent open. How much we didn't discuss. I can call'em and find out.

As for it being a secret. YES IT WAS... during WWII. I's all out their now. This feature for the P-51 is not modeled in, therefore, that blaze of speed is why Pony drivers get left behind so easily in-game vs 109's that have no business hauling away, nore the 190 which many have felt that these two planes were very compadible with each other. Come November this will be all mute when PF comes out. Hopefully all the lessons leared in the IL-2 run will be emplimented into PF and BoB.

S!

BSS_Vidar

XyZspineZyX
08-11-2004, 11:27 PM
Sorry Sunburst,
CFS2 and CFS3 and AVHistory, all have pilots (WWII, test and modern) that have "verified" their particular models.

I'm sure Jane's had some verify their's too.

LEXX_Luthor
08-12-2004, 12:08 AM
Contradiction alert

This internet pilot claims to never have known about the radiator thrust until told by PhD professor, but then claims to have beem trained for [modern] P~51 flying.

just saying. Invitation to resolve the contradiction offered. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Spock!


__________________
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"You will still have FB , you will lose nothing" ~WUAF_Badsight
"I had actually pre ordered CFS3 and I couldnt wait..." ~Bearcat99
"Gladiator and Falco, elegant weapons of a more civilized age" ~ElAurens
:
"Damn.....Where you did read about Spitfire made from a wood?
Close this book forever and don't open anymore!" ~Oleg_Maddox http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif

ASH at S-MART
08-12-2004, 12:31 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LEXX_Luthor:
Contradiction alert

This internet pilot claims to never have known about the radiator thrust until told by PhD professor, but then claims to have beem trained for [modern] P~51 flying.

just saying. Invitation to resolve the contradiction offered. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Spock__!__
<HR></BLOCKQUOTE>I noticed that too.. either a trol or a senial dude! http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

And as for secret... even if it was.. the min the first P51 fell behind enmy lines it wasnt anymore! http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

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LEXX_Luthor
08-12-2004, 12:43 AM
Secret? Did they tell the P~51 pilots? http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

From reading Porkyson (sp?), I read they never told the MiG pilots about the existence of Su~2. They wanted to keep Su~2 a Secret too.



__________________
http://ubbxforums.ubi.com/images/smiley/10.gif Flyable Swedish "Gladiator" listed as J8A ...in Aces Expansion Pack

"You will still have FB , you will lose nothing" ~WUAF_Badsight
"I had actually pre ordered CFS3 and I couldnt wait..." ~Bearcat99
"Gladiator and Falco, elegant weapons of a more civilized age" ~ElAurens
:
"Damn.....Where you did read about Spitfire made from a wood?
Close this book forever and don't open anymore!" ~Oleg_Maddox http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif

Eddie_W
08-12-2004, 04:18 AM
The Meredith Effect was actually a British discovery (by F.W. Meredith) in 1935. The original report is reproduced here: http://www.airspacemag.com/asm/mag/supp/jj99/Mustang.html. The Spitfire radiators attempted to make some use of it, but as the development was in its infancy when the Spitfire was designed, that implementation wasn't particularly effective.

So it wasn't a "top secret" innovation. A clever aerodynamic trick, but one that was published for everyone to see several years before the Mustang was even conceived.

WUAF_Badsight
08-12-2004, 05:42 AM
yea it was called The Meredith Effect

the Germans knew about it as well as the russians im sure ...... it was discovered well in advance of WW2 wasnt it ?

Skychimp did have a big thread on this way at the Mustangs release

the boost from the Rad was enough to counter the effect of the rad being opened into the airstream wasnt it ?

.
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lbhskier37
08-12-2004, 05:46 AM
So no one still told me why there was an adjustable radiator if wide open made you go the fastest? Shouldn't there be only a closed setting for warmup and an open setting for uberfast then? LoL

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WUAF_Badsight
08-12-2004, 05:56 AM
your partly correct

wide open wasnt the fastest

IIRC , partly open was the best setting to get the effect occuring best , as opposed to completely closed

.
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lbhskier37
08-12-2004, 06:03 AM
That makes more sense to me, I can see how this would offset cooling drag at lower radiator settings, but with that flap open all the way hanging out into the wind, in addition to the drag of that huge radiator on the Stang full open radiator must have been pretty draggy.(in addition to having less of nozzle so less of a "boost" effect) The P51 was a great plane, but it still flew by all the same rules as everyone elses and like most planes of that time didn't use loads of "secret" technology.

http://lbhskier37.freeservers.com/2005VRSCSE.jpg (http://www.il2skins.com/?action=list&whereauthorid=lbhkilla&comefrom=display&ts=1049772896)
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BSS_Vidar
08-12-2004, 06:59 AM
Guys.. please. I said I flew a P-51 in March. I didn't say I was checked out in one. "Sizzelin' Liz" is a two-seater with duel controls. Don't look too far into it.

BSS_Vidar

Loki-PF
08-12-2004, 07:00 AM
RE: The Mustang, its radiator and speed.

( the complete discussion thread this excerpt was taken from is at link below )

http://forums.ubi.com/eve/forums?q=Y&a=tpc&s=400102&f=63110913&m=15210063&p=1

MUSTANG

Commentary by Lee Atwood.


What made the P-51 Mustang the fastest fighter of World War II (before the German jet came along)? The answer depends on whom you ask. The editors at Air & Space/Smithsonian asked the late Lee Atwood, vice president at North American Aviation when the fighter was born, and the question started an interesting correspondence. Atwood's explanation of what gave the Mustang the edge over the Spitfire and Curtiss P-40 was the design of its cooling system, especially the radiator duct's variable exit.
In an address to the Yorkshire Air Museum in June 1998, Atwood described the effect of the design on the Mustang's performance. An excerpt from his speech follows, along with drawings he made to illustrate his point to the editors.

In 1940 we had a young, energetic, and first-class engineering department with competence in aerodynamics, structures, materials, and thermal technologies as developed up to that time, and the factory had a nucleus of expert machine shop, tooling, and production personnel. We gave the Mustang design credit to Edgar Schmued who led the design room effort and brought the components together under the direction of Raymond Rice, who succeeded me as a chief engineer, and the technical specialists.

All these and many others contributed significantly to the project, including Colonel, now General (Retired), Mark E. Bradley who directed the installation of the 85-gallon fuselage tank. He then demonstrated that the longitudinal instability created by this weight behind the pilot could be managed by the combat pilots, and the effective endurance could be increased by some two hours.

In considering the speed performance of the Mustang, which is really its primary advantage and distinction, it is necessary to adjust one's thinking and point of reference to a rather early period in the science of aerodynamics. In the 1930s, there was no jet propulsion, and by any measure of comparison, the technical resources, personnel employed, test equipment and financial expenditures were really insignificant when compared to the aerospace establishment of today. Of course, the basics were there--which involved derivations of Newton's laws and Bernoulli's hydraulic principles--and aero sciences had been basically defined by Prandl, von Karman, and many other mathematical and scientific authorities, but applications to actual aircraft were relatively crude and empirical. Wind tunnel models were the primary proving element in design, and there were still many elements of such testing that had to be estimated or extrapolated with opinion and hope.

In these circumstances it is not very surprising that, among these early practitioners of aeronautical engineering, there were discontinuities of information and differences of opinion on various fine points in the application of general aerodynamic science, as then known, to actual airplane design. This was most apparent in one of the critical aspects of airplane design during the period of reciprocating engines and propeller-driven airplanes. The liquid-cooled designs favored in England and Germany--and also used in the United States and other countries--were generally considered of lower drag because of their in-line cylinder configuration. Air-cooled engines were generally of radial design, with all cylinders facing the cooling air stream, and the diameter was considerably larger.

The well-known radiator became the automobile standard early on, and everyone in the pre-war era had various experiences with these installations and their belt-driven fans. The common experience usually involved adequate cooling at cruising speeds, with frequent over-heating on mountain grades or slow traffic, and the fans were not always adequate to control the temperature. Generally, most people had an occasional bad experience with an overheated engine.

Airplane radiators had a lot of the same troubles, and while separate cooling fans were not seriously considered, ground cooling from propeller circulation alone was frequently inadequate. Basically, the radiators were designed to cool the engines at full power in a climb--which was usually something like half the maximum possible level flight speed with the same power--so at high speed, the cooling capacity was much more than needed.

Now it is clear that we were then quite sure that, as in an automobile, there was no reasonable dynamic use for the warm air discharged from a radiator, and a low and medium speeds, up to say 200 miles per hour, that was quite true. The temperature rise was small, and the expansion was correspondingly modest, and heat energy recovery was insignificant.

However, as engine power increased and better aerodynamic shapes were developed in monoplane designs, we were all slow to realize that, with a normally ducted radiator at high speed, we had at our disposal a really remarkable air pump.

This air pump, like all pumps, had three elements--a compressor stage, a metering or valving stage (radiator core), and a discharge function through an air outlet. This began to be a considerable pumping action as speeds approached 300 miles per hour--and at 400 miles per hour, it had a large potential and could be a considerable fraction of the airplane's total power equation, since the pumping pressure increases as the square of the speed. To make this automatic pump effective, only one thing was required, and that was to choke the outlet enough to keep the pressurized airflow through the radiator just adequate for cooling and to discharge this compressed air at the highest speed possible.

This intuitively easy to follow and was also logical from a general streamlined design point of view--which all designers tried to follow as a matter of course. The potential magnitude of this effect was more difficult to appreciate, however, and since little or no data were available, these possibilities were overlooked in most cases.

In the case of the Mustang, the air duct pumping system at full speed at 25,000 feet was processing some 500 cubic feet of air per second, and discharge speed of the outlet was between 500 and 600 feet per second relative to the airplane. This air jet counteracted much of the radiator drag and had the effect of offsetting most of the total cooling drag. To offer some approximate numbers, the full power propeller thrust was about 1,000 pounds and the radiator drag (gross) was about 400 pounds, but the momentum recovery was some 350 pounds of compensating thrust--for a net cooling drag of only some 3% of the thrust of the propeller.

This air discharge had what can actually be called a regenerative effect. Maximum aircraft speed is the point where the line of power available, created in the engine and delivered by the propeller, crosses the line of power required to propel the plane through the air. Since the propelling force of the pressurized air from the radiator discharge increases as the square of the speed, we have the favorable situation where the faster you fly the more help you are getting from this regenerative air pumping system.

Since this high speed phenomenon could not be effectively measured by regular wind tunnel model test, it was viewed as ephemeral or even imaginary by many in the engineering practice. Actually, it is quite real and has a close relationship with jet propulsion.

Regarding the Mustang, I have always referred to the work of F. W. Meredith of the RAE, whose report (RAE No. 1683) of August 1935, greatly influenced me as chief engineer for North American Aviation to offer the British Purchasing Commission the ducted radiator design configuration in 1940. That report showed how the momentum loss in the cooling radiator could be largely restored when excess cooling air was being forced through the radiator at high speed. As noted before, this involved closing the air exit enough to get a substantial back pressure behind the radiator which largely restored the momentum loss--which was quite large as described above. This was possible, in Meredith's words, because the outlet was "adjusted to suit the speed,o and back pressure was available accordingly.

Here again, while Meredith's analysis was coherent and mathematically instructive, he failed to convey the practical aspects through an example or two, although he did offer a chart showing drag reduction for various discharge area ratios and conditions. The point I am making was that his work was generally in unfamiliar mathematical terms and was poorly understood. In fact, in two cases I know about, it was described in terms of mild ridicule. In any case, some if not most of the designs of wartime aircraft, including the Spitfire, failed to get the full advantage of this available air pump.

It should be pointed out here that the controversy and misunderstanding of the Meredith Effect on the performance of the Mustang developed largely because it was essentially impossible to get a reasonable measure of the effect from wind tunnel models at the time. The mass flow and momentum could not be accurately measured on a scale model, and no large tunnels were fast enough--200 to 400 miles per hour--to get meaningful results.

It has been reported that Messerschmitt made extensive efforts to determine the reason for the low drag of the Mustang, but his wind tunnel measurements did not disclose the restoration of momentum to the radiator cooling air, and most probably could not have done so with the wind tunnel equipment available at the time.

At this point I would like to interpolate what is , to me, a most fascinating element in Meredith's 1935 report. As you may have noted, I have made no reference to the thermal element in the momentum recovery of the radiator cooling air and at the temperatures involved, the air expansion was relatively small and could be neglected. Real jet propulsion, however, involves fuel burning, and the velocity of the gases and heated air is greatly augmented by this high temperature.

In his report, undoubtedly independent of Whittle's jet engine work, Meredith suggests piping the engine exhaust heat and gases to discharge behind the radiator to heat the discharged air just as burning fuel would do. This would have increased the volume and velocity of the discharged air at the same back pressure and increased the favorable thrust force.

Of course, the thrust of the short stack exhausts had been recognized by Sir Stanley ****** of Rolls-Royce in his book, NOT MUCH OF AN ENGINEER, and others, but Meredith's suggestion might have produced a much more powerful effect, but it involved complications and practical difficulties. As far as I can determine, it was never tried on any airplane.

This brings me to the Spitfire comparison, although that is probably a poor choice of words. That airplane was in a class by itself and at the top level of defense against the Luftwaffe in 1940, and was undoubtedly the most important defensive weapon in history. It was some 1,000 pounds lighter than the Mustang and was at the peak of interceptor efficiency and was essentially in classic conformity with the objectives of the RAF fighter command. It overmatched its opposition and was there when most needed.

In the cold illumination of hindsight, however, and probably for reasons I have outlined above, it missed the opportunity to restore much of the air flow momentum to the radiator cooling air and, with it, a possible speed increment of more than 20 miles per hour. The late Jeffrey Quill, Supermarine test pilot, describes the incorporation of the Meredith Effect in the Spitfire in his book, SPITFIRE, A TEST PILOT'S STORY, and that the radiators were enclosed in ducts under the wings. Here I would like to quote from an article "The Mustang Margin" I wrote for the AIR POWER HISTORY JOURNAL which involves some background and detail on the subject. It will, of course, be glad to try to answer any questions you may have at the end of my presentation.

"The most notable and probably the first application of the Meredith Effect was incorporated in the Supermarine Spitfire, one of the world's most successful airplanes. Over 20,000 were built in various models, but the Mark IX, with the Merlin -61 engine, was typical of the later wartime production, and a sketch of this model with detail of the radiator installation is shown. Two aspects of this design are significant. First, the radiator outlet has two positions--that is, fully open and partly closed--and cannot be progressively 'adjusted to suit the speed.' Second the inlet upper wall is a continuation of the lower surface of the wing and expands the duct cross section by rapidly curving upward.

"The first, the non-adjustable exit, of course, is a deviation from Meredith's dictum and precludes the progressive build-up of pressure behind the radiator with increasing speed. However, the second can only be judged in hindsight, from an airplane design point of view. The inlet seemed to be configured properly to recover the ram air pressure, and the first Mustang design had a similar entry opening. It was later apparent that the thin boundary layer of air flowing along the lower surface of the wing was progressively thickening ahead of the duct opening, and that the flow would break away at a point on the upward curve of the duct wall. While the resulting turbulent unsteady flow apparently did not create a serious vibration, it certainly reduced the efficiency of the radiator and prevented a more complete closure of the exit opening, which is necessary to develop the jet thrust. Very interestingly, the R.A.E. Subcommittee on Aerodynamics in 1936--in commenting on the Meredith and Capon reports--rather accurately predicted this problem: 'Experiments upon air-cooled engines in the 24-foot tunnel have shown that it is necessary to pay particular attention to the design of the entrance to cowlings and the cooling ducts in order to avoid loss of energy by the formation of eddies.' (Somewhat easier said than done at that time.)

"In the case of the Mustang, the duct volume was larger and flow instability more violent, creating an unacceptable vibration and rumble. Resourceful engineers at North American, working with wind tunnel models, overcame the problem by lowering the intake upper lip below the wing surface boundary layer, thus beginning a new upper duct surface. In this design, the flow expanded gradually as the duct velocity decreased, and the pressure at the radiator face was reasonably uniform. This permitted the appropriate closure of the exit with a temperature-controlled power actuator, and a minimum pressure drop across the radiator consistent with efficient radiator function and cooling demand.

"As a result, the cooling drag was estimated at only 3 percent of the total and used only something like 40 horsepower for cooling purposes. While the comparable power used for cooling by the Spitfire is not available to me, the measurements made by Rolls-Royce show a total power required for the same speed (400 mph) as 200 horsepower more for the Spitfire than for the Mustang.

"Records show the P-51D's speed was 437 mph and the Spitfire Mk IX speed was 405 mph. While the Spitfire had exposed tail wheel and other small differences from the Mustang, most of the speed difference was in the cooling drag. The Mark VIII with retracted tail wheel is rated at 414 mph at a somewhat higher altitude. Advanced models of both airplanes with higher performance were produced late in the war, but were not available in significant numbers before V-E Day, May 8, 1945.

"It seems that most other contemporary airplanes attempting to take advantage of the Meredith Effect failed for one reason or another to combine an efficient duct system with a properly designed and regulated exit-closing mechanism and did not develop the energy recovery inherent in the Meredith method. They generally used 10 percent or more of their power available at high speed to overcome cooling drag. A notable exception was the DeHavilland Mosquito multi-purpose plane with the same Rolls-Royce engines and which used a wing leading edge radiator mounting with a short and direct inlet duct. The controllable exit opening had a minimum area little more than half that of the Spitfire, and while it was a larger two-engine airplane, it had a speed of 425 mph.

"Since jet engines do not require cooling systems of the type described here, the subject has become moot and of little current importance. There was a time, however, when this rather insignificant subject made a critical difference."


Regards,

SkyChimp

Eddie_W
08-12-2004, 07:03 AM
If anyone actually bothered to read the info I linked to http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif they would realise that it results in a significant reduction of drag - approx 10% of thrust was used to counteract cooling drag on a standard installation. On the Mustang, which was one of the few aircraft that properly used the Meredith effect, that was cut to around 3%, a big saving. The reason it worked so well on the Mustang was that the cooling vent was infinitely variable, and thermostatically controlled, to take the maximum advantage of the effect.

OldMan____
08-12-2004, 08:22 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
I flew a P-51 here about 3 months ago. It's a dream to fly. The sound file (in-game) is nothing like it. The roll rate in-game on the P-51 is too fast and snappy. Also the FM as flight control inputs and responces that are too strong. I accedently trying to prevent my plane from tipping over due to exccessive taxi speed. Deflecting the aileron stop the tip over. And I couldnt stop chucklin' for a half hour.

In flight, I opened the radiator vent just to see what it would do. The airspedd in a P-51D at 4,500' was 460 kts. (Never see THAT in level flight in-game "without a dive")
There's a lot more issue regarding just plane vs another here, but rather the entire flight model design. Short of CFS2's terrible trim adaptation, it has the most accurate flight model available for that erra. It has its many problems, but the basic flight model is correct.
Putting the PF plane in a FB game,,,?
They'ld get eatin alive.

BSS_Vidar<HR></BLOCKQUOTE>

LOL... 460 knots? Do you know that is 851 km/h ? Never saw anything saying a P51 can reach that in LEVEl flight. This would put it in same level as german jets.. or are you saying simple heating from air in cooling system is enought to give thrust as much as TWO HUGE Turbojets like the ones in Me262 ? LOL! 10 or 15% plus thurst is NOT ENOUGH to give that edge on speed (dreag increases in square of speed.. as well as the force needed to overcome it.


MAYBE 460 mph.. that is 736km/h....

If brute force does not solve your problem... you are not using enough!

BSS_Vidar
08-12-2004, 09:33 AM
Oooops! Ur right. It was 460 MPH http://ubbxforums.ubi.com/images/smiley/35.gif Just under 400 kts. I called the owner of Sizzlein' Liz to find out for sure. The modern airspeed indicator he has installed has the MPH in large characters and kts in smaller charaters inside the arch. I guess I'm too use to flying Kts only when I was in the Navy. http://ubbxforums.ubi.com/images/smiley/blink.gif

The exhaust vent for the radiator has three settings. Closed, Manual, and Auto. When we opened it during our flight it was set to auto.

Just a little about me folks:
- Over 2,200 hrs in various Naval Aircraft and the B-52 (what a hoot)
- 526 arrested landings
- Top Gun - DCM 1988
- Pax River Md.
Aircraft Test and Evaluation and Weapons profile (flite) evaluation. i.e. Mil settings for Mk 80 series bombs and Mk 46 Torpedo
- Ejections.. JUST ONE, and that was enough.

BSS_Vidar

VF-10_Snacky
08-12-2004, 09:39 AM
Former tailhook SENSO here Vidar. how do

http://www.x-plane.org/users/531seawolf/P38Sig2.jpg

ASH at S-MART
08-12-2004, 09:54 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
Oooops! Ur right. It was 460 MPH http://ubbxforums.ubi.com/images/smiley/35.gif Just under 400 kts. I called the owner of Sizzlein' Liz to find out for sure. The modern airspeed indicator he has installed has the MPH in large characters and kts in smaller charaters inside the arch. I guess I'm too use to flying Kts only when I was in the Navy. http://ubbxforums.ubi.com/images/smiley/blink.gif

The exhaust vent for the radiator has three settings. Closed, Manual, and Auto. When we opened it during our flight it was set to auto.

Just a little about me folks:
- Over 2,200 hrs in various Naval Aircraft and the B-52 (what a hoot)
- 526 arrested landings
- Top Gun - DCM 1988
- Pax River Md.
Aircraft Test and Evaluation and Weapons profile (flite) evaluation. i.e. Mil settings for Mk 80 series bombs and Mk 46 Torpedo
- Ejections.. JUST ONE, and that was enough.

BSS_Vidar<HR></BLOCKQUOTE>All well and good... Just glad we got that TOP SECRET thing cleared up.. Which was another perfect example of a phd talking out his A! Which is why it is so important to take evertying you see read and hear with a grain of salt. In short, Ill take the reading off of a meter over what 10 phd's said the meater should read! http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif

ASH HOUSEWARES GROOVY (http://www.garnersclassics.com/wavs/army/groovy.wav)
http://surbrook.devermore.net/adaptionsmovie/ash.jpg

BSS_Vidar
08-12-2004, 04:59 PM
Well,
I tend to believe the PhD, the owner of Sizzil' Liz, The P-51 ace that lives here in north Florida, and the German Ace that lives down in Orlando.

BTW, I never said "TOP SECRET". Your filling in your own words there. I said "one of the bigest secrets about the Pony's speed performance". To elaborate, no one knew just how effective it was in the Mustang's performance. Not that the effect itself was classified.

BSS_Vidar

FbusterMk3
08-13-2004, 10:40 AM
I don't buy this at all, the reason the Mustang was so fast was the Merlin engine, and the PROBABLE reason it flew faster than a Spitfire with the same engine was the higher induced drag of the Spits large area wings. The spits' rads contributed to slowing it down rather than the stangs' radiator speeding it up.
Someone mentioned 15% thrust increase, there are early jets that got less thrust augmentation from thier afterburners!
Only my opinion - just doesn't sound right to me http://ubbxforums.ubi.com/images/smiley/16x16_smiley-indifferent.gif

BfHeFwMe
08-13-2004, 11:03 AM
I can't get past the aileron on taxi part. http://ubbxforums.ubi.com/images/smiley/88.gif

At what taxi speed do they begin to take effect? Think I'll be chuckling for half an hour also. http://ubbxforums.ubi.com/images/smiley/59.gif

Kurfurst__
08-13-2004, 04:31 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Eddie_W:
If anyone actually bothered to read the info I linked to http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif they would realise that it results in a significant reduction of drag - approx 10% of thrust was used to counteract cooling drag on a standard installation. On the Mustang, which was one of the few aircraft that properly used the Meredith effect, that was cut to around 3%, a big saving. The reason it worked so well on the Mustang was that the cooling vent was infinitely variable, and thermostatically controlled, to take the maximum advantage of the effect.<HR></BLOCKQUOTE>

Hmm, the Bf 109F had the same thing in 1940, infinitively variable inlet and exit flaps on the radiators, thermostatically controlled (with option of manual control in case of thermostat failure); the boundary layes was picked up inside the radiator to ensure maximum effiency and no separation. In other words, it took advantage of the same effect as the Mustang did with a similiar radiator design.

Bf 109F/G/K radiator scheme :

http://109lair.hobbyvista.com/techref/systems/cooling/f_airflow.jpg



http://www.x-plane.org/users/isegrim/nw2004set7.jpg

We're walking in the air
We're floating in the midnight sky
And everyone who sees us greets us as we fly

[This message was edited by Kurfurst__ on Sat August 14 2004 at 04:56 AM.]

p1ngu666
08-13-2004, 05:15 PM
didnt know it had variable inlet. early p51/a36 did but was later left out

http://www.pingu666.modded.me.uk/mysig3.jpg
&lt;123_GWood_JG123&gt; NO SPAM!

OldMan____
08-13-2004, 05:26 PM
These people that complain about ailerons working at taxi. Did you EVER programmed a physics simulation? Do you know how hard it is? So you think It would worth the effort os spendig dozens of hours to change the force applications just to make correct a case that represents 0.0005% of the time?

Bite your tongues... Oleg did a pretty awesome work on physics on this game. There are many things much more important than that. When any of these guys can make a simulation of the plane (ONLY AT TAXI).. then come back and flame!!!

If brute force does not solve your problem... you are not using enough!

Chuck_Older
08-13-2004, 06:44 PM
haven't read the whole thread, I admit. Lots of info, and what i read was pretty thorough

But the Meredith effect the P-51 enjoyed should roughly be enough to counter the parasitic drag of that huge doghouse under the wing.

*****************************
Killers in America work seven days a week
~ Clash

JaBo_HH-BlackSheep
08-14-2004, 05:16 AM
109 used the same thing and no-one is complaining about a "speed-boost" when opening radiator.... http://ubbxforums.ubi.com/images/smiley/crazy.gif


http://home.arcor.de/sebastianleitiger/FB/Screens/Fw%20190A-4guns.JPG (http://forums.ubi.com/eve/forums?a=tpc&s=400102&f=63110913&m=185103665)

[This message was edited by ToP_BlackSheep on Sun August 15 2004 at 06:56 AM.]

WereSnowleopard
08-14-2004, 08:04 AM
Speaking in English...It sound like Urban Legend to me.

Chuck_Older
08-14-2004, 09:02 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WereSnowleopard:
Speaking in English...It sound like Urban Legend to me.<HR></BLOCKQUOTE>

What does? This whole wacky idea of the door on the back of the P-51's scoop generating positive thrust?

Why? Just because it sounds odd to you doesn't mean it's not true.

And again- the effect of the thrust did not ADD to the speed. It negated the drag loss from the doghouse scoop. Didn't add a few MPH, it eliminated the loss of a few MPH.

**
Y'all should read Loki's long quote from SkyChimp. By 'cooling drag' it means the drag from the cooling system: including the scoop. Instead of a full loss of speed from drag caused by a large structure sticking out in the airflow, the actual loss was from a structure 3% of the size of the scoop because of the Meredith effect**

*****************************
Killers in America work seven days a week
~ Clash

[This message was edited by Chuck_Older on Sat August 14 2004 at 08:11 AM.]

WWMaxGunz
08-14-2004, 12:40 PM
Actual loss of total power at full speed.
Efficiency of the system dropped rapidly with drop in speed.
Article also said the efficiency didn't even begin till about 300mph.

HP to cooling fans was?
How much recovered by ducted heat pump?

Interesting to hear that 109's also had this, only better of course.
Sources?


Neal

Chuck_Older
08-14-2004, 01:46 PM
?Cooling fans? http://ubbxforums.ubi.com/infopop/emoticons/icon_confused.gif I am looking at a diagram of the P-51 cooling systems and I see no cooling fans...Am I misunderstanding you, Max? The P-51 has two cooling systems, and I see no fan in either... there are two pumps to pressurize the systems, no fans.


Actually North American Aviation VP Atwood mentions in the book "The Mustang story" that:
Quote
" It is apparent that the principle of cooling drag reduction by restoration of the momentum of the air after it passed throught the radiator was well known before the war and had been applied in aircraft configurations of the Spitfire, the Bf109, and others but it seems that, as is often the case, "The Devil is in the Details"."
Unquote

Clearly implying that the Bf109 did not do it better.

He also mentions the number of Meredith's Royal Aircraft Establishment report on low cooling drag- it is No. 1683, if anyone cares to look that up.

Also VP Atwood mentioned that in June 1995, in Aeronautical Journal, the P-51 enjoyed a cooling system drag of 2-3% of the actual total drag

The scoop on the P-51 was moved away from the bottom of the fuselage very much on purpose, to deal with the boundary layer in front of the scoop. It stands to reason this boundary layer effect would influence the efficiency of the Bf109's radiators aw well- except that the Bf109 does not, to my knowledge, have the radiator inlets moved away from the bottom of the wings.

http://img.photobucket.com/albums/v441/Chuck_Older/myp51.jpg
Killers in America work seven days a week~
Clash

GT182
08-14-2004, 02:30 PM
BSS_Vidar, you can lead a horse to water but you can't make him drink. Same applies here. Lee Atwood's commentary confirms what you said. Now people just have to learn to believe what they read. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

NO offense to anyone but you gotta quit beating everything someone says to death. Did you ever stop to think that if the a/c in FB were made to fly like the "real thing", we'd probably never get one off the ground. And if we did we might not be able to land it. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

"GT182" / "Stab/JG51_vonSpinmeister"
www.bombs-away.net/forums (http://www.bombs-away.net/forums)
www.stabgeschwader51.com (http://www.stabgeschwader51.com)
"Fly to Survive, Survive to Fly"

BSS_Vidar
08-14-2004, 02:39 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FbusterMk3:
I don't buy this at all, the reason the Mustang was so fast was the Merlin engine http://ubbxforums.ubi.com/images/smiley/16x16_smiley-indifferent.gif<HR></BLOCKQUOTE>

Sir,
That's not what this post is about. No doubt the Merline was behind its increased speed performance after the power plant change. This is about the effectiveness of the radiator exhaust position not being modeled into the P-51's performance. This P-51 is slow in a flat run compared to the real thing. Modeling this effect into the FM may give it the speed it deserves. Also making it not so easy be out run by 109's 10 years its senior and be more compadible to the 190's speed.

BSS_Vidar

Chuck_Older
08-14-2004, 02:46 PM
quote:
--------------------------------------------------------------------------------
Originally posted by FbusterMk3:
I don't buy this at all, the reason the Mustang was so fast was the Merlin engine
--------------------------------------------------------------------------------

OK, let me ask this carefully, then...

Why wasn't the Spit Mk IX as fast as the P-51D then? They both used the same engine.

Surely you understand that aerodynamics has something to do with it.

The Spit is 1,000 pounds lighter and is slower than the P-51D
Spit IX: 405 mph
P-51D: 437 mph

that's 652 km/h versus 703 km/h

Plenty of sources and info has been given. You can do three things with that info:

1) believe it
2) check up on it yourself
3) discount it

Ball's in your court http://ubbxforums.ubi.com/images/smiley/16x16_smiley-indifferent.gif

http://img.photobucket.com/albums/v441/Chuck_Older/myp51.jpg
Killers in America work seven days a week~
Clash

JaBo_HH-BlackSheep
08-14-2004, 03:19 PM
the "huge" wings of the Spitfire increased drag quite dramaticly this is one reason why Kurt Tank choose wide, but narrow wings for the TA, less drag equal lift.

While the Spitfire was more like Turn and Burn (later versions not realy but still prefered) the P51D was a high-speed escort plane, more suited for BnZ or energy-fighting than "pure" TnB. It was an aerodynamic verry clean, low drag construction.

BTW: i remember a British test where the P51D could not reach it's "top-Speed" while accelerating from level flight.
(but i don't know the source for this right now)

For the Coolers on the 109.

The cief constructer of Messerschmit already knew about the problems with the air intake.
U can build them big, but this will increase drag. U can make them verry small, but the cooling will suffer.
The constructers team invented the so called "jet - coolers" where the hot air was exausted to the rear. This resulted in a minimisation of the drag these coolers caused.
when u open them you will have more indicated drag, but to the same time you will get some "boost" from the hot-air exaust, it was meant that drag and boost eliminate each other to keep overall drag and therefor change of flight-performence as low as possible.

I read an article about this in an aviation magazine.
I think it was similar to the system the P51's used.

http://home.arcor.de/sebastianleitiger/FB/Screens/Fw%20190A-4guns.JPG (http://forums.ubi.com/eve/forums?a=tpc&s=400102&f=63110913&m=185103665)

[This message was edited by ToP_BlackSheep on Sat August 14 2004 at 02:34 PM.]

[This message was edited by ToP_BlackSheep on Sat August 14 2004 at 02:35 PM.]

Chuck_Older
08-14-2004, 03:22 PM
Sure, also the angle of the front canopy was probably responsible, too


~edit

a July 1942 report from Rolls Royce estimated that 13 mph could be added to the Spit's speed by using a better air exit closure on the radiators
http://img.photobucket.com/albums/v441/Chuck_Older/myp51.jpg
Killers in America work seven days a week~
Clash

[This message was edited by Chuck_Older on Sat August 14 2004 at 02:31 PM.]

Bearcat99
08-14-2004, 05:19 PM
I have yet to get my Pony anywhere near 703kph in a flat run.

<UL TYPE=SQUARE>http://www.jodavidsmeyer.com/combat/bookstore/tuskegeebondposter.jpg (http://www.tuskegeeairmen.org)[/list]<UL TYPE=SQUARE>vflyer@comcast.net [/list]<UL TYPE=SQUARE>99thPursuit Squadron IL2 Forgotten Battles (http://www.geocities.com/rt_bearcat)[/list]
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IMMERSION BABY!!

SkyChimp
08-14-2004, 07:12 PM
Did I write that? I don't remember that post. I must be getting old.

Here's a good drawing of the Mustang's radiator effect:

http://members.cox.net/us.fighters/radiator.jpg

Regards,
http://members.cox.net/us.fighters/signature.jpg

Loki-PF
08-14-2004, 09:39 PM
You da man SC! http://ubbxforums.ubi.com/images/smiley/11.gif

JaBo_HH-BlackSheep
08-15-2004, 01:59 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by SkiChimp:
The heated air was ejected through the rear of the duct at a higher velocity than when it entered, thus offering some energy recovery.<HR></BLOCKQUOTE>

so it IS the same purpose as on the 109's, reducing drag.

http://home.arcor.de/sebastianleitiger/FB/Screens/Fw%20190A-4guns.JPG (http://forums.ubi.com/eve/forums?a=tpc&s=400102&f=63110913&m=185103665)

WUAF_Badsight
08-15-2004, 02:39 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
This P-51 is slow in a flat run compared to the real thing. Modeling this effect into the FM may give it the speed it deserves. Also making it not so easy be out run by 109's 10 years its senior and be more compadible to the 190's speed.

BSS_Vidar<HR></BLOCKQUOTE>

you do realise the 700 kmh quoted speed for the Mustang is T.A.S ?!?!?

& that its at 6700 odd meters ?

you got a Mustang in FB that is faster than RL ! ! ! on the deck
( again for emphasis ..... ! ! ! ! ! ! ! ! ! ! ! ! ! ! )

whats your problem ?

huh ?

.
__________________________________________________ __________________________
actual UBI post :
"If their is a good server with wonder woman views but historic planesets...let me know!" http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif

[This message was edited by WUAF_Badsight on Sun August 15 2004 at 08:56 PM.]

WUAF_Badsight
08-15-2004, 02:45 AM
the Mustang has been given a boost in speed since its release (it used to only do 680ish . . . . thats still LESS than 4% incorrect) , AND the fiftys have been boosted dramatically AND it has a higher than RL G-limit & yet still BSS_Vidar wants more http://ubbxforums.ubi.com/images/smiley/blink.gif http://ubbxforums.ubi.com/images/smiley/blink.gif http://ubbxforums.ubi.com/images/smiley/blink.gif

http://ubbxforums.ubi.com/images/smiley/52.gif

.
__________________________________________________ __________________________
actual UBI post :
"If their is a good server with wonder woman views but historic planesets...let me know!" http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif

FbusterMk3
08-15-2004, 02:51 AM
[QUOTE]Originally posted by SkyChimp:
Did I write that? I don't remember that post. I must be getting old.

Here's a good drawing of the Mustang's radiator effect:

Could anyone expand on that little qualifier "during design conditions"

WWMaxGunz
08-15-2004, 04:53 AM
Fifties boosted dramatically. http://ubbxforums.ubi.com/infopop/emoticons/icon_rolleyes.gif
Like they were correct before as shotguns. http://ubbxforums.ubi.com/images/smiley/crazy.gif

Just surely more fun for some people who want that back is what.


Neal

WWMaxGunz
08-15-2004, 05:18 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Chuck_Older:
?Cooling fans? http://ubbxforums.ubi.com/infopop/emoticons/icon_confused.gif I am looking at a diagram of the P-51 cooling systems and I see no cooling fans...Am I misunderstanding you, Max? The P-51 has two cooling systems, and I see no fan in either... there are two pumps to pressurize the systems, no fans.


Actually North American Aviation VP Atwood mentions in the book "The Mustang story" that:
Quote
" It is apparent that the principle of cooling drag reduction by restoration of the momentum of the air after it passed throught the radiator was well known before the war and had been applied in aircraft configurations of the Spitfire, the Bf109, and others but it seems that, as is often the case, "The Devil is in the Details"."
Unquote

Clearly implying that the Bf109 did not do it better.

He also mentions the number of Meredith's Royal Aircraft Establishment report on low cooling drag- it is No. 1683, if anyone cares to look that up.

Also VP Atwood mentioned that in June 1995, in Aeronautical Journal, the P-51 enjoyed a cooling system drag of 2-3% of the actual total drag

The scoop on the P-51 was moved away from the bottom of the fuselage very much on purpose, to deal with the boundary layer in front of the scoop. It stands to reason this boundary layer effect would influence the efficiency of the Bf109's radiators aw well- except that the Bf109 does not, to my knowledge, have the radiator inlets moved away from the bottom of the wings.

http://img.photobucket.com/albums/v441/Chuck_Older/myp51.jpg
Killers in America work seven days a week~
Clash<HR></BLOCKQUOTE>

Just re-read, the fans was on cars only. It was cooling drag. Prop thrust 1000HP and
cooling drag of 400HP with recovery at 350HP -- all at max speed. Lose speed, the
cooling drag and recovery both drop although I gather the recovery % drops faster.

From that 109 diagram the 109 scoop is supposed to shunt all the turbulence of the boundary
layer above the radiator. I'd like to see more on that. Simply how as the space inside
widens from the duct opening that the boundary layer takes this sharp turn at high speed
and stays glued right tight over the radiator, for one. For the other, even if it passes
clearly over the radiator it is still fluxuating turbulent which damages the ability on
the P-51 to maintain pumping backpressure and why they had to lower the scoop. But on
the 109, it works a thermodynamic impossibility and returns 100% efficiency if I understand
one poster here saying 109 had complete recovery of drag! Even the P-51 only got 350 out
of 400 back, the 3% was compared to total power. To get 0% loss you have to have 100%
recovery. There was a mechanism that *maybe* helped or *maybe* just sucked air through.
Is there anything that points to it working?


Neal

SkyChimp
08-15-2004, 07:41 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FbusterMk3:
[QUOTE]Originally posted by SkyChimp:
Did I write that? I don't remember that post. I must be getting old.

Here's a good drawing of the Mustang's radiator effect:

Could anyone expand on that little qualifier "during design conditions"<HR></BLOCKQUOTE>

Yes. During design and testing it was felt that not only could the design reduce drag, but that the system could produce a net thrust. In practice however, it's doubtful that the system actually completely overcame drag. But even so, it was an extremely efficient design.

Regards,
http://members.cox.net/us.fighters/signature.jpg

hop2002
08-15-2004, 07:53 AM
Skychimp, I don't know if it's any use, or if you already know it, but from a test report of the P-51D in British service, running on 150 octane, at low supercharger gear altitudes, they say they had to open the radiator to 8.5" for proper cooling, rather than the 7.5" that was normally used (presumably with 100/130)

That's for level speed runs. It's the only info I have on how far exactly the radiators were opened. Do you know what the maximum opening was? And did the radiator fully close, or was "closed" just a smaller opening, like on the Spit? Looking at the diagram, it seems to fully close.

Chuck_Older
08-15-2004, 08:02 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WWMaxGunz:

Just re-read, the fans was on cars only. It was cooling drag. Prop thrust 1000HP and
cooling drag of 400HP with recovery at 350HP -- all at max speed. Lose speed, the
cooling drag and recovery both drop although I gather the recovery % drops faster.

From that 109 diagram the 109 scoop is supposed to shunt all the turbulence of the boundary
layer above the radiator. I'd like to see more on that. Simply how as the space inside
widens from the duct opening that the boundary layer takes this sharp turn at high speed
and stays glued right tight over the radiator, for one. For the other, even if it passes
clearly over the radiator it is still fluxuating turbulent which damages the ability on
the P-51 to maintain pumping backpressure and why they had to lower the scoop. But on
the 109, it works a thermodynamic impossibility and returns 100% efficiency if I understand
one poster here saying 109 had complete recovery of drag! Even the P-51 only got 350 out
of 400 back, the 3% was compared to total power. To get 0% loss you have to have 100%
recovery. There was a mechanism that *maybe* helped or *maybe* just sucked air through.
Is there anything that points to it working?


Neal<HR></BLOCKQUOTE>

http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif
That's why I asked if I misunderstood you. I know that you understand how this stuff works, so the fan thing really threw me for a loop!

The turbulent air entering the 109's rads was mainly what I was referring too as well, but I hadn't considered the possibilty of a seperate system on the 109 to aid recovery. I do not know the answer to that one; I have very little Bf109 reference.

http://img.photobucket.com/albums/v441/Chuck_Older/myp51.jpg
Killers in America work seven days a week~
Clash

SkyChimp
08-15-2004, 09:05 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by hop2002:
Skychimp, I don't know if it's any use, or if you already know it, but from a test report of the P-51D in British service, running on 150 octane, at low supercharger gear altitudes, they say they had to open the radiator to 8.5" for proper cooling, rather than the 7.5" that was normally used (presumably with 100/130)

That's for level speed runs. It's the only info I have on how far exactly the radiators were opened. Do you know what the maximum opening was? And did the radiator fully close, or was "closed" just a smaller opening, like on the Spit? Looking at the diagram, it seems to fully close.<HR></BLOCKQUOTE>

Hop, I've yet to find a definitive range of motion for the P-51's exit flap. I've got manuals on the P-51B/C/D/H and it's not in any of them.

However, when it is referred to as closed I don't think that literally means closed. I think it means the exit flap was up as far as it could go but that there was still an opening for air to exit.

There is an NAA document in one of my books that has to do with NAA exploring a way to minimizing the "rumble" a pilot would hear when the flying with the exit "closed." NAA looked into modifying the intake duct of the P-51B - but all other parts of the cooling system stayed the same. There were 6 different intake ducts tested, and in each case the chart shows the tests were conducted with Oil Flap open from 0.6 inches to 8.0 inches, and the Coolant Flap open from 1.3 inches to 14.5 inches. I would think this would represent the range of motion (or exit opening measure) for the flap - 1.3 inches (closed) to 14.5 inches (fully open). I'm not sure how the measure is taken (internally?). I don't know if my conclusion is correct and if anyone knows better I could be convinced otherwise.

I'm still on the fence as to whether or not the exit was "closed", partly open or fully open when top-level speed was obtained. I tend to believe that it was open, at least partly. I'd think that a level run to top speed would cause temperature to rise enough to cause the flap to open - at least some. Here's what a British manual says regarding the P-51B:

http://members.cox.net/us.fighters/radiator2.jpg

Regards,
http://members.cox.net/us.fighters/signature.jpg

ASH at S-MART
08-15-2004, 12:05 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by SkyChimp:
Yes. During design and testing it was felt that not only could the design reduce drag, but that the system could produce a net thrust. In practice however, it's doubtful that the system actually completely overcame drag. But even so, it was an extremely efficient design. <HR></BLOCKQUOTE>I seem to recal that the placment of the intake was also a factor.. There was an NACA test that showed if the placement of the intake can be placed lower than the body it greatly reduced... something.. I think it was drag? Thing was the NACA figured out that alot of turblance was in and around the body of the aircraft.. And that is where most intakes start.. But note.. the P51 intake is special.. In that it is placed lower.. Away from the body and outside that turblance area

ASH HOUSEWARES GROOVY (http://www.garnersclassics.com/wavs/army/groovy.wav)
http://surbrook.devermore.net/adaptionsmovie/ash.jpg

Kurfurst__
08-15-2004, 12:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Chuck_Older:
The scoop on the P-51 was moved away from the bottom of the fuselage very much on purpose, to deal with the boundary layer in front of the scoop. It stands to reason this boundary layer effect would influence the efficiency of the Bf109's radiators aw well- except that the Bf109 does not, to my knowledge, have the radiator inlets moved away from the bottom of the wings.

Clash<HR></BLOCKQUOTE>

Well that`s why it has a seperate boundary layer separator inside the radiator structure of the 109F, to pick up the boundary layer, seperate it from the radiator ducting, and exclude interference from it within the radiator hoursing. http://ubbxforums.ubi.com/infopop/emoticons/icon_wink.gif Just look at the illustration.

Moving out the inlet further down, outside of the boundary layer on the Mustang is just another way of solution, with different gains and offsets (less turbulance, sligtly more area). Such idea was not unknown to Messerscmitt either - just look on the Bf 109 supercharger air intake, which does this exactly.

http://www.x-plane.org/users/isegrim/nw2004set7.jpg

We're walking in the air
We're floating in the midnight sky
And everyone who sees us greets us as we fly

WWMaxGunz
08-15-2004, 09:06 PM
Atwoods' report gives a figure of 400HP cooling drag with estimated 350HP
recovery from Meredith Effect. Not exactly a net gain, just very efficient
cooling. And that is at full speed condition. Lower speeds, lower cooling
drag and even more lower recovery.

Had the exhaust been routed into the after-radiator volume then *maybe* there
would have been a net effect but really, much longer exhaust pipes with bends
exiting into a pressurized environment might also lose the engine as much or
more power than they stood to gain... would you bet on it? It would also
have made a nice cleaning job back in there between flights.


Neal

FA_Whisky
08-18-2004, 02:24 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> the Mustang has been given a boost in speed since its release (it used to only do 680ish . . . . thats still LESS than 4% incorrect) , AND the fiftys have been boosted dramatically AND it has a higher than RL G-limit & yet still BSS_Vidar wants more
<HR></BLOCKQUOTE>

It still does not reach 703 kmph at 6700meters without overheating and blowing the engine.
The G-limit of the P51d was +8 g's. With a pilot blacking out at 4-5 g's than how is it possible to reach +8g's and losing a wing when there are no signs of blacking out. This happened to me at about 700kmph groundlevel making a right turn......To bad i don't have nay prove.

If anyone can post tracks of the plane reaching max speeds without overheating i would like to see them. Or maybe Oleg can show how his team does it.

WUAF_Badsight
08-18-2004, 11:27 PM
nearly all planes overheat trying to hit their topspeed

is the Mustang supposed to be different &gt;?

.
__________________________________________________ __________________________
actual UBI post :
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WUAF_Badsight
08-18-2004, 11:30 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by FA_Whisky:

The G-limit of the P51d was +8 g's. With a pilot blacking out at 4-5 g's than how is it possible to reach +8g's and losing a wing when there are no signs of blacking out.<HR></BLOCKQUOTE>

i dunno , looks like the Mustang dont have the same blackout that other planes do ...... it must be better wouldnt you say

.
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lrrp22
08-19-2004, 01:34 PM
No, I wouldn't say.

The Mustang has a very quick and profound blackout- no doubt because of the effective high speed elevators. But claiming it has a 'better' blackout than other airplanes is ludicrous.

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WUAF_Badsight:


i dunno , looks like the Mustang dont have the same blackout that other planes do ...... it must be better wouldnt you say

.
__________________________________________________ __________________________
actual UBI post :
"If their is a good server with wonder woman views but historic planesets...let me know!" http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif
<HR></BLOCKQUOTE>

WUAF_Badsight
08-20-2004, 08:15 AM
well its reaching wing snap over-G without blacking out

thats a pretty big advantage over a host of other fighters in FB

many cant reach Over-G without hitting complete blackout

so your Pony isnt giving you the blackout that otherplanes inflict on their users

why is that not better B/O moddeling Lrrp ?

.
__________________________________________________ __________________________
actual UBI post :
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VFA-195 Snacky
08-20-2004, 09:21 AM
So I take it Badsight isn't a Mustang fan.LOL


http://www.x-plane.org/users/531seawolf/b_a_presidential_first.jpg
"Navy1, Call the Ball- Roger Ball."

BSS_Vidar
08-20-2004, 10:02 AM
I was following 200-300 meters at 640kph behind a 190 that was constantly opening the gap between us. He "snap" into a virtical climb in front of me and didn't loose a wing or black out. I tried to just follow behind and gradually lead my climb due to having some distance behind him. I didn't even tunnel out and my right wing snapped off. That's just flat wrong no matter how you see it. And no, I don't see not blacking out before my wing comes off as an advantage. http://ubbxforums.ubi.com/images/smiley/blink.gif

BSS_Vidar

WWMaxGunz
08-20-2004, 11:51 AM
Pilots don't black out instantly or even hit grey the moment G's reach some
point. If G's hit very quickly, the pilot state should lag in time a bit,
but just a bit is all.

Leading another plane means you are pulling more G's. Anything but lag
pursuit means more G's than the other and the harder the turn the more
you nose should be behind his path in order to be flying the same G's.

It's a sim. Everything is calculation. Reality, things just happen and
every instant is right. Sim, things get calculated when they do and then
things like wings snap and blackouts happen. What to expect, perfection?
Doctor, it hurts when I do this! Then don't do that!


Neal

BSS_Vidar
08-20-2004, 12:45 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WWMaxGunz:
Pilots don't black out instantly or even hit grey the moment G's reach some
point. If G's hit very quickly, the pilot state should lag in time a bit,
but just a bit is all.<HR></BLOCKQUOTE>

Not an entirely true statement Gunz. Read my posts in the G Forces and Aircrew Physiology thread. Instantainious Black outs are a fact if the manuever is abrupt enough.

And that 190 should have pulled way more G's than I did snapping his plane to the virtical at what he called in excess of 700kph like that. I was in trail 2-300 meters behind at 640 kph gradualy cutting the corner and never got more than 10 degrees nose up before that wing came off. No plane could pull that manuever without the plane or the pilot paying for it.

BSS_Vidar

FA_Whisky
08-20-2004, 04:24 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> well its reaching wing snap over-G without blacking out

thats a pretty big advantage over a host of other fighters in FB

many cant reach Over-G without hitting complete blackout

so your Pony isnt giving you the blackout that otherplanes inflict on their users

why is that not better B/O moddeling Lrrp ?
<HR></BLOCKQUOTE>

How about we turn that around....
The "wing snap over-G" SOMETIMES happens before the blackout G's reached. I have had the same as BBS_Vider stated. But in my case i was the one being chased by a La7. He turned inside me(more G's) and i lost a wing turning at 650kmph(flat turn). Something is still not 100% ok, i think there is a glitch in the calculation and that the P51d is more effected by it than other planes. I have never seen a 190 A9 lose a wing like the P51 does but you can really snap it around at high speeds. The high G-load limts of every planes just needs some more tuning. It might be better in PF or BoB.

HellToupee
08-20-2004, 04:29 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WWMaxGunz:
Pilots don't black out instantly or even hit grey the moment G's reach some
point. If G's hit very quickly, the pilot state should lag in time a bit,
but just a bit is all.<HR></BLOCKQUOTE>

Not an entirely true statement Gunz. Read my posts in the G Forces and Aircrew Physiology thread. Instantainious Black outs are a fact if the manuever is abrupt enough.

And that 190 should have pulled way more G's than I did snapping his plane to the virtical at what he called in excess of 700kph like that. I was in trail 2-300 meters behind at 640 kph gradualy cutting the corner and never got more than 10 degrees nose up before that wing came off. No plane could pull that manuever without the plane or the pilot paying for it.

BSS_Vidar<HR></BLOCKQUOTE>

well you still dont always black out instantly at high gs, you need to sustain high gs.

http://lamppost.mine.nu/ahclan/files/sigs/spitwhiners1.jpg

BSS_Vidar
08-20-2004, 09:53 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by HellToupee: well you still dont always black out instantly at high gs, you need to sustain high gs.http://lamppost.mine.nu/ahclan/files/sigs/spitwhiners1.jpg <HR></BLOCKQUOTE>

That's not entirley true either. That buddy of mine that I mentioned in the G's and Aircrew Physiology thread avoided smakin' into a mountain by pulling abruptly on the stick and blacked out instantly. He didn't come too till he realized his Hornet was corkscrewing virticaly through 10,000 ft MSL/5,000 ft AGL. The G's he exposed himself to were only a second or two in duration, but were excessive enough to keep him oblivious for almost a mile of virticle flight.
During my ejection, the G's were so strong, I didn't fully come too till I was 10 ft underwater. It was a very low invirted egress to say the least.

BSS_Vidar

WWMaxGunz
08-21-2004, 09:47 AM
Aerobatics pilots have pulled momentary high G's without blacking out in the course
of competition.

"National Aeronautics and Space Administration (NASA) data show that a range of +8Gz
to -6Gz (the limit of the accelerometer) can occur during aerobatic competition, but
such values lack the time element."

www.faa.gov/avr/afs/as91-61.txt (http://www.faa.gov/avr/afs/as91-61.txt)

People are wetware. We have imperfect senses, judgement, and memory which is affected
by the very event of blood flow diminishemnet that causes the blackout. We also are
not sensitive as balance scales, we operate on blood in cells, capillaries and veins
with valves and can ride out brief bumps with any preparedness and decent health. Of
course the ones who can go farther started out ready and in good shape, probably ate
light and right as well. The article linked to has a bit to say of diet and all.


Neal

BSS_Vidar
08-21-2004, 10:35 AM
Link is bad Gunz.
In controlled flight I have never blacked out. I've tunneled out many times though - there is a difference.
Stunt pilots usually don't have G-suits which is a feat in its own. The Blue Angels don't wear jet jeans either. They do however know precisely when they are going to induce load on the plane therefore preparing "physicaly" for the manuever. In ACM, you don't have that luxury. If I know I'm about to enduce 6 G's on my body, I start the "Hut" of Grunt" proceedure well before the manuever. I can maintain my visual acuity throughout the manuever. F-16 pilots must be rated up to 9 Gs in the cetrifuge to qualify to deploy in the Falcon. They are automaticaly disqualified if they black out completely. Hence they are given several seconds before the full 9 G's to physicaly prepared.
Articles, links, charts, and graphs don't quite explain it fully. You have to experience it for yourself. I have tunneled out INSTANTLY from the onslaught of unexpected G's, and Blacked out INSTANTLY from ejection which is 150 Gs at seat ignition.

But then again, I've made many-a-trips through the Wendy's drive through. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif

BSS_Vidar

WWMaxGunz
08-21-2004, 11:03 PM
Try http://www.faa.gov/avr/afs/ac91-61.txt
Weird, usually leaving the http:// out of a www address makes no difference but
this time it does for me.

Competition prop aerobatics fliers may go from large + to large - G's in 2 seconds
flat. And they do series of manuevers. 150 G's very momentarily and you blacked
out... does the word shock apply? That's a little way for a fraction of a second
at +8. Fun part is only having so many G's for a fraction of a second, I think
that's what takes the training. I also don't think that relying on memory from a
brain that's just been blacked out is any way to judge an event, perhaps the docs
have something to say about that.

Clearly though, the FAA does regard that without the time factor at G's, fliers
do take momentaries without losing it. In that document they also state that what
you eat, how you slept, your alt and a number of other factors change your response
to G's, how much till you go gumby and all that.


Neal

LLv34_Stafroty
08-22-2004, 03:13 AM
there was made record of G forces by one Us aerobatics flier, he was able to make 11G for really short period, and that was without G-suit. he had cauges in his plane to read G forces and camera recordin the readings of that cauge. 150G:s sounds way too high, and no man could handle that much of forces.

JaBo_HH-BlackSheep
08-22-2004, 03:59 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by BSS_Vidar:
I was following 200-300 meters at 640kph behind a 190 that was constantly opening the gap between us. He "snap" into a virtical climb in front of me and didn't loose a wing or black out. I tried to just follow behind and gradually lead my climb due to having some distance behind him. I didn't even tunnel out and my right wing snapped off. That's just flat wrong no matter how you see it. And no, I don't see not blacking out before my wing comes off as an advantage. http://ubbxforums.ubi.com/images/smiley/blink.gif

BSS_Vidar<HR></BLOCKQUOTE>

gues we are not playing the sme game.
my P51D is able to dive to 830kph (IAS) and pullout to levelfly works.
I pull it the same way as i would pull a 190.
so show me a track.

EDIT: here is mine. could go 830+ lost on aileron at 880 or something.
I zommed up and dived down several times.
Pulled close to or even till blackout.
http://home.arcor.de/sebastianleitiger/FB/Tracks/P51%20Dive.zip

BTW: maybe u guys got shot?
since 2.04 i have problems hearing the "hitsounds" when someone is shooting at my plane sometimes.

BBTW: does anyone know the G-limit of the airframe (wings) for a P51 ?

http://home.arcor.de/sebastianleitiger/other%20Stuff/we%20rule%20your%20world3.jpg (http://www.hell-hounds.de)

[This message was edited by ToP_BlackSheep on Sun August 22 2004 at 03:21 AM.]

OldMan____
08-22-2004, 08:38 AM
The statement that a P51 in FB will snap wings when following a 190 , is RIDICULOUS!!

Try to give an instnt pull out with a 190 to see what happens!! We do not loose wings.. we just loose ALL sustentatrion and fall spinning like a rock!! So test othe rplanes before saying anything. I never was able to break P51 wings unless in supid maneuver (pulling all stick back and to side instantly). I never was able to loose a P51 wing during combat (damaged wings do not count). If I want to break a P51 wing.. I must prepare myself to do so.. and TRy hard!!

If brute force does not solve your problem... you are not using enough!

jugent
08-22-2004, 11:27 AM
This is a joke, isnt it?
As far as i know, pressure inside a structure expands at all directions, and if no mechanical device prevents it from expanding towards the radiator, it would pressure at that direction to. That much for 10% more trust, as would be of some houndred hp.
Cant all the correct physical words.

WWMaxGunz
08-22-2004, 12:23 PM
That explains why jet engines don't work.
Compressor powered by turbine powered by flow which is even all directions....

No big thing. As the report says, the theory was never proved about the
Meredith Effect in the P-51.

For any plane this is true of, using top speed and power to calculate drag
coefficient would be wrong since with a boost at top speeds the coefficient
would be falsly low.


Neal

LuftLuver
08-22-2004, 05:26 PM
G tolerance is intentionally modeled lower for the mustang. There are two stances on this issue:

1 - Those who know it's true

2 - Those who know it's true and want to keep it that way

So I begin by follow a 190 flat and level and he begins a series of evasives. If the speed is high enough, often I will only be able to loosely follow through greyed tunnel vision. I'm still on him, and think "fine, he's about to black out too."

No. In fact I watch this thing do 2 or even 3 additional hard turns attempting to get free. All the while I am throttled back and giving the stick only gentle movement. This argument about higher elevator authority is a big pile.

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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"All your road courses are belong to us."

Kurfurst__
08-23-2004, 10:26 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LuftLuver:
G tolerance is intentionally modeled lower for the mustang.
<HR></BLOCKQUOTE>

Save for the fact Oleg confirmed that max. G-load was set to be the exact SAME on all planes - 15G maximum. So the only reason the Mustang keeps breaking is because its elevator is much more effective than historically it was, and capable of putting the plane to loads other planes controls cant do.

Guess its a backfire of the Mustang fans continous enforcement to make the planes elevators very light, despite in rl they were heavy.

http://www.x-plane.org/users/isegrim/nw2004set7.jpg

We're walking in the air
We're floating in the midnight sky
And everyone who sees us greets us as we fly

LuftLuver
08-23-2004, 11:22 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Kurfurst__:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LuftLuver:
G tolerance is intentionally modeled lower for the mustang.
<HR></BLOCKQUOTE>

Save for the fact Oleg confirmed that max. G-load was set to be the exact SAME on all planes - 15G maximum. So the only reason the Mustang keeps breaking is because its elevator is much more effective than historically it was, and capable of putting the plane to loads other planes controls cant do.

Guess its a backfire of the Mustang fans continous enforcement to make the planes elevators very light, despite in rl they were heavy.

http://www.x-plane.org/users/isegrim/nw2004set7.jpg
_
We're walking in the air
We're floating in the midnight sky
And everyone who sees us greets us as we fly_<HR></BLOCKQUOTE>

Hello kurf,

You are talking about G tolerance effects on wing shedding. I was refering to G tolerance in regards to pilot phisiology. I should have clarified that.

I don't care about the G load and wing shedding. I don't have trouble with it. I've seen a Ki84 do it, but no 109/190s.

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
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"All your road courses are belong to us."

robban75
08-23-2004, 01:35 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LuftLuver:
I don't care about the G load and wing shedding. I don't have trouble with it. I've seen a Ki84 do it, but no 109/190s.
<HR></BLOCKQUOTE>

In order to break the wings of a D-9 you have to use combat flaps. The D-9 can't turn nearly as fast as the P-51.

http://members.chello.se/unni/D-9.JPG

Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. During dogfights at altitudes of between about 10,000 and 24,000ft, usual when meeting the Russians, I found that I could pull the D-9 into a tight turn and still retain my speed advantage. In the descent the Dora-9 picked up speed much more rapidly than the A type; in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

LuftLuver
08-23-2004, 03:31 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by robban75:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LuftLuver:
I don't care about the G load and wing shedding. I don't have trouble with it. I've seen a Ki84 do it, but no 109/190s.
<HR></BLOCKQUOTE>

In order to break the wings of a D-9 you have to use combat flaps. The D-9 can't turn nearly as fast as the P-51.
<HR></BLOCKQUOTE>

To clarify, I think the 109/190 should have sound structures as in RL. Correct me if I am wrong please, but higher wing loading yields stronger wings, right?

As for P51 wing shedding, I think all the FB Mustangs have been delivered from the bad lot, with faulty gear latches. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-wink.gif At any rate, it doesn't affect me (I may have done it once since the patch) so I'm not willing to kick up a fuss about it.

Back to my original post: G tolerance seems to be lower for P51 PILOTS. Since the mini-debacle where the wrong numbers were punched in for the P47/D7 (resulting in it missing 300hp and being limited to 30lbs stick force), I tend to wonder if the p51 numbers have been typed in correctly. http://ubbxforums.ubi.com/images/smiley/35.gif

Now Oleg, about those G suits. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-tongue.gif

""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
http://members.cox.net/kinetic/SigImages/tonystewartchevy.jpg
"All your road courses are belong to us."

WWMaxGunz
08-23-2004, 05:43 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by LuftLuver:
To clarify, I think the 109/190 should have sound structures as in RL. Correct me if I am wrong please, but higher wing loading yields stronger wings, right?
<HR></BLOCKQUOTE>

Negative. The one has nothing to do with the other. Loading is about weight supported
per square area of wing only.


Neal

LuftLuver
08-23-2004, 07:06 PM
Ok thanks GUnz,

My main point being that 109/90 wings were in fact strong so I don't expect to see them snapping off much.

Geez, how does wing snapping keep popping up. Should have posted in the physio thread. http://ubbxforums.ubi.com/images/smiley/93.gif

Aaron_GT
08-24-2004, 05:51 AM
BSS_Vidar wrote:
"In flight, I opened the radiator vent just to see what it would do. The airspedd in a P-51D at 4,500' was 460 kts. (Never see THAT in level flight in-game "without a dive")"

You wouldn't get it in WW2 with +18 boost as modelled in the P-51 we have.

Aaron_GT
08-24-2004, 06:04 AM
"Not an entirely true statement Gunz. Read my posts in the G Forces and Aircrew Physiology thread. Instantainious Black outs are a fact if the manuever is abrupt enough."

At an airshow on Sunday a pilot flying an aerobatic plane (SU-something or other) flew a cobra maneouver - flying level then pulling up very abruptly into a 12G maneouver (the plane is rated to +- 20G). The pilot gave commentary throughout the maneouver and certainly didn't black out. It was very impressive. The plane also had 1:1 power:weight and he hung it motionless on the prop for around 5 seconds later on in the display. The Blue Eagles were also there, looping helicopters.

robban75
08-24-2004, 06:09 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>BSS_Vidar wrote:
"In flight, I opened the radiator vent just to see what it would do. The airspedd in a P-51D at 4,500' was 460 kts. (Never see THAT in level flight in-game "without a dive")"

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Are you saying that the P-51 was capable of 460 kts, (833km/h) in level flight?
Or did you mean 460 mph, (726km/h) @ 4500m?

http://members.chello.se/unni/D-9.JPG

Oberleutnant Oskar-Walter Romm thoughts on his aircraft.

"I found the Fw 190D-9 to be greatly superior to those of my opponents. During dogfights at altitudes of between about 10,000 and 24,000ft, usual when meeting the Russians, I found that I could pull the D-9 into a tight turn and still retain my speed advantage. In the descent the Dora-9 picked up speed much more rapidly than the A type; in the dive it could leave the Russian Yak-3 and Yak-9 fighters standing."

OldMan____
08-24-2004, 08:31 AM
I already asked him about that.. and he already answered.

If brute force does not solve your problem... you are not using enough!