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Viper2005_
02-01-2006, 10:57 AM
After many requests in my Mustang III performance issues thread I have decided to test the P-47.

I have placed this thread in GD because at this stage, having done no testing, I have no bugs to report. If and when I discover an issue I will start a thread in ORR.

My tests will be measured against the performance data available here:

http://www.spitfireperformance.com/p-47/p-47.html

As there is test data for the D-10, I shall start there and move through the versions.

I shall concentrate on FTH and speed as these are the simplest parameters to measure accurately.

This thread does not have a red or blue affiliation or agenda. It's just a flight testing thread. Please do not fill it with whine or otherwise spam it.

Test results to follow.

Diablo310th
02-01-2006, 02:27 PM
ENGINEERING DIVISION MEMORANDUM
REPORT SERIAL NO. ENG-47-1774-A
15 July 1944

FLIGHT TESTS ON THE REPUBLIC
P-47D AIRPLANE, AAF NO. 42-26167
USING 44-1 FUEL
The airplane and engine handled well at all altitudes at the higher powers. At 70.0" Hg., water injection, a maximum speed of 444 MPH was obtained at 23,200 feet. At 65.0" Hg., with water a high speed of 439 MPH at 25,200 feet


Holy Toledo...woo hoo If only it was that in game.

Viper2005_
02-01-2006, 06:49 PM
Ok here come some results:

P-47D10:

Top speed at sea level: 548 km/h, 50" Hg with water injection, 2700 rpm, ~18,000 rpm on the turbo (and if you'll believe that you'll believe anything!). From this point on I shall disregard the turbo gauge as it is clearly mendacious...

FTH ~ 8500 m, top speed 690 km/h; 680 km/h still
possible at 10,000 m, at which point manifold pressure had fallen to around 43" Hg with water injection at 2700 rpm.

No overheating experienced at altitude; at sea level overheat was eventually experienced after a very long run. This aircraft appears to be one of the very few in IL2 with realistic performance in this regard.

The cockpit was incorrectly configured in that the supercharger control was locked in the "off" position, making the constant 18,000 rpm from the turbo even more suspect in my estimation...

BigKahuna_GS
02-01-2006, 06:56 PM
S!



Diablo310th
Posted Wed February 01 2006 13:27
ENGINEERING DIVISION MEMORANDUM
REPORT SERIAL NO. ENG-47-1774-A
15 July 1944

FLIGHT TESTS ON THE REPUBLIC
P-47D AIRPLANE, AAF NO. 42-26167
USING 44-1 FUEL
The airplane and engine handled well at all altitudes at the higher powers. At 70.0" Hg., water injection, a maximum speed of 444 MPH was obtained at 23,200 feet. At 65.0" Hg., with water a high speed of 439 MPH at 25,200 feet


Holy Toledo...



It will be mate---per Oleg ! http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

Viper2005_
02-01-2006, 07:14 PM
The D-22 seems identical to the D-10 in all respects other than looks; it appears that the bomb racks under the wings are just graphical and don't impact the flight model when the aeroplane is flown clean.

Grey_Mouser67
02-01-2006, 07:29 PM
This is true...I have a source that states the D-22 and onward received the paddle blade prop.

I have heard vauge claims of increased climb rate and accelaration, speed at lower altitudes as a result of this propeller, but I've never heard quantifiable numbers and test results.

Can one of the more knowledgable Jug folks confirm or deny the prop and clear up what its real performance enhancement was?

Viper2005_
02-01-2006, 07:42 PM
P-47D-27

Manifold pressure increased to 63" Hg.

Top speed at sea level now 575 km/h.

FTH reduced to ~7700 m, at which height a top speed of 703-705 km/h was available.

Great difficulty has been experienced when test flying the P-47 due to its excellent energy retention. Altitude excursions of ~10 m can produce considerable speed changes, and there is a tendency to yo-yo around the true level flight top speed.

In addition it takes an extremely long time to bleed off energy, so great care must be taken when testing to avoid posting optimistic values if there has been a descent of even 10 m in the past couple of minutes.

At 10 km boost is down to 43" Hg again as with the other aircraft, but the D-27 can only manage ~665 km/h, and seems to accelerate much more slowly than the early models.

Viper2005_
02-01-2006, 08:26 PM
P-47D

Manifold pressure increased to 70" Hg.

Maximum speed at sea level 582 km/h (it seems much happier to converge to an accurate top speed than the -27 was). However, 585 km/h can be maintained at very low level by a brave pilot - presumably due to ground effect. This is probably not practical for most people without reference to external views as airscrew clearance is decidedly limited.

FTH is reduced to 6700 m with ram, at which height a top speed of 700-705 km/h is available.

At 8500 m 51" Hg is available from the engine, giving a maximum speed of ~ 580 km/h.

At 10,000 m, 665 km was available; at this height one might as well be flying a D-27.

Viper2005_
02-01-2006, 09:02 PM
Comparison with test reports:

The P-47D-10 and D-22 perform in a manner which is in excellent agreement with this report:

http://www.spitfireperformance.com/p-47/p-47d-74616.html

Note that turbocharger rpm in this report is limited to 18,250 and manifold pressure is limited to 52.6" Hg.

In game the P-47D-10 and D-22 give about 50" Hg. Interestingly enough the P-47 in the above report delivers this manifold pressure at almost exactly 8500 m.

I therefore conclude that the P-47D-10 and D-27 have been modelled accurately based upon a manifold pressure of 50.6 "Hg and a limiting turbocharger rpm of 18,250.

I will leave it to the P-47 experts to debate the historical accuracy of this rating.

Tests of the P-47D-27 show it to be ~ 10 mph slower than the razor back P-47s when operated at equal manifold pressure, rpm and altitude.

This is interesting, since the 70" curve for the P-47D presented here:

http://www.spitfireperformance.com/p-47/p47d-44-1-level.jpg

gives speeds about 10 mph faster than those obtained by the P-47D in game.

It is gratifying to report that the aircraft used in the generation of the test report was a razorback.

However, there is a fly in the ointment, since the curve generated gives a maximum speed of just under 348 mph (ie 560 km/h) at sea level with 70" Hg, and only about 305 mph with 52" Hg.

It would therefore appear that the P-47D in all its models is somewhat too fast at sea level, but very accurate at high altitude. This is backed up by the fact that the D-10 tested at 56" Hg was capable of only 333 mph at sea level which is ~ 536 km/h.

I was rather hoping that it would be too slow rather than too fast so that I could brandish my impartiality. Oh well. I'll put a hard hat on...

BigKahuna_GS
02-01-2006, 09:32 PM
S!



Viper--At 10,000 m, 665 km was available; at this height one might as well be flying a D-27.


Hya Viper,

The P47D is a good 10-15mph slower at critical alt of the P47D-27. Oleg modeled it this way. Also the speed curves you are looking at for the P47D on 150grade fuel show that it is 10-15mph too slow depending on altitude. At sea level it is close.

I already have an email from Oleg stating the speed will be tuned (increased) to reflect the P47D on grade 150 fuel chart/speed curves.

We will have to see how that turns out in 4.03

__

Viper2005_
02-01-2006, 09:39 PM
The curves from this report:
http://www.spitfireperformance.com/p-47/p47-26167.html
reflect the performance of a razorback P-47D. This one in fact:

http://www.spitfireperformance.com/p-47/p47d-44-1-side.jpg

As such I would expect the P-47D we have in game, which is fitted with a draggy bubble canopy to be slower than those performance curves indicate.

BigKahuna_GS
02-01-2006, 11:53 PM
S!


Viper--As such I would expect the P-47D we have in game, which is fitted with a draggy bubble canopy to be slower than those performance curves indicate


I wouldn't Viper because the P47D bubble top models had a bigger engine with more horsepower.
If anything I would think it would be faster. Look at the speed increases of the P47M & P47N models.

About each succesive P47D bubble top got more HP and was over boosted more than the model before it.

So actualy you bring up a good point. I need to find which version of R2800 was used in the razorback model for testing and adjust it for the higher HP engines. I think I'll discuss this Lrrp.


__

Viper2005_
02-02-2006, 03:19 AM
The report states that the R-2800-63 was the engine used in the 70" Hg razorback tests.

Kwiatos
02-02-2006, 03:38 AM
What about roll rate of P-47??

From these site i found :

" F. Maneuvrability
No acrobatics were tried but rolling into turns and changing directions is very easily accomplished because of very light aileron forces. Rudder and elevator have somewhat heavier forces but not objectionably so. The radius of turn is large and the stick forces become very heavy in a turn requiring both hands on the stick. "

P-47 have light aileron and have good roll rate at different speed (even at high speed) - its similar to the NACA chart.

In game version 4.02 P-47 have accurate roll rate at slow speed but too slow roll at high speed ( have 35 deg/s instead 70 deg/s). Even A6M2-5 have the same roll rate and Ta-152 H have even better http://forums.ubi.com/groupee_common/emoticons/icon_frown.gif

Have any other data and suorce about P-47 roll rate?

WOLFMondo
02-02-2006, 03:41 AM
I thought all roll rates are off at higher speeds for all aircraft, not just the P47 or especially the 190's.

Kwiatos
02-02-2006, 04:23 AM
Not all - some are pretty close. But some are uncorrect and cause non historical adventages and disadventages between planes like ex. P-47 - A6M - Ta152.
Even in fw190 have little to slow roll rate at high speed in game it still have good roll and you dont feel that sth is wrong. But if you get P-47 with very bad at now roll rate at high speed which should be much better you feel that these bird dont roll.

WOLFMondo
02-02-2006, 04:55 AM
I remember the original P47 in this sim. To me it rolls, climbs, dives and turns like a dream compared to what was here a few years back!

Diablo310th
02-02-2006, 07:24 AM
Viper...S!! thanks for the tests. It's really appreciated. The roll rate is off at high speed for several planes. It really hampers the Jug alot tho. The key is keeping the Jug fast and with it's slow roll rate it's at a disadvantge in many situations. I'm suprised at your comments about retaining energy well. Maybe my flying is so poor but energy retention on the Jug seems poor especially in a zoom climb but again maybe it's just my flying.

Viper2005_
02-02-2006, 08:05 AM
I'm talking about very small angles of climb and dive <3-5º

Grey_Mouser67
02-02-2006, 06:20 PM
Originally posted by Viper2005_:
Comparison with test reports:

The P-47D-10 and D-22 perform in a manner which is in excellent agreement with this report:

http://www.spitfireperformance.com/p-47/p-47d-74616.html

Note that turbocharger rpm in this report is limited to 18,250 and manifold pressure is limited to 52.6" Hg.

In game the P-47D-10 and D-22 give about 50" Hg. Interestingly enough the P-47 in the above report delivers this manifold pressure at almost exactly 8500 m.

I therefore conclude that the P-47D-10 and D-27 have been modelled accurately based upon a manifold pressure of 50.6 "Hg and a limiting turbocharger rpm of 18,250.

I will leave it to the P-47 experts to debate the historical accuracy of this rating.

Tests of the P-47D-27 show it to be ~ 10 mph slower than the razor back P-47s when operated at equal manifold pressure, rpm and altitude.

This is interesting, since the 70" curve for the P-47D presented here:

http://www.spitfireperformance.com/p-47/p47d-44-1-level.jpg

gives speeds about 10 mph faster than those obtained by the P-47D in game.

It is gratifying to report that the aircraft used in the generation of the test report was a razorback.

However, there is a fly in the ointment, since the curve generated gives a maximum speed of just under 348 mph (ie 560 km/h) at sea level with 70" Hg, and only about 305 mph with 52" Hg.

It would therefore appear that the P-47D in all its models is somewhat too fast at sea level, but very accurate at high altitude. This is backed up by the fact that the D-10 tested at 56" Hg was capable of only 333 mph at sea level which is ~ 536 km/h.

I was rather hoping that it would be too slow rather than too fast so that I could brandish my impartiality. Oh well. I'll put a hard hat on...

Unfortunately this report does not mention which propeller was available or on the plane. Both were available...I can't remember the source, but I do recall reading that some units would switch props depending on the mission...the paddle blade was better at low alt. I think and the standard prop better at high alt.

If anyone can find anything useful and objective on the performance increase of the paddle blade prop, please share.

I have flight journal P-47 edition that runs down some of the variants...it is there that it is listed the -22 got the new prop.

jds1978
02-02-2006, 09:18 PM
good stuff Viper.

it was a blast flying with you last weekend.
keep the data rolling!

GR142-Pipper
02-03-2006, 12:02 AM
Originally posted by Viper2005_:
Ok here come some results:

P-47D10:

Top speed at sea level: 548 km/h, 50" Hg with water injection, 2700 rpm, ~18,000 rpm on the turbo (and if you'll believe that you'll believe anything!). From this point on I shall disregard the turbo gauge as it is clearly mendacious...

FTH ~ 8500 m, top speed 690 km/h; 680 km/h still
possible at 10,000 m, at which point manifold pressure had fallen to around 43" Hg with water injection at 2700 rpm.

No overheating experienced at altitude; at sea level overheat was eventually experienced after a very long run. This aircraft appears to be one of the very few in IL2 with realistic performance in this regard.

The cockpit was incorrectly configured in that the supercharger control was locked in the "off" position, making the constant 18,000 rpm from the turbo even more suspect in my estimation... Top speeds at different altitudes is certainly important. However, another very important issue is acceleration. Do you have any data on P-47 acceleration characteristics?

GR142-Pipper

Slickun
02-03-2006, 08:23 AM
P-47M accelerated slightly better than the P-51D @ 67" hg, sea level, 250 mph starting speed. It accelerated slightly less as the P-38L (1600 hp), same conditions. All three gained about 4 feet per second.

An excell chart is fairly easily made that can give you acceleration data. All you need is air pressure, thrust, weight, and drag.

Drag is easily as big a factor as weight and thrust, something that is often neglected when comparing types. For example, the P-51 comes off poorly in any late war comparison of thrust to weight, but when drag is also factored in, it compares very favorably.

The Jug was pretty draggy, as was the P-38.

Viper2005_
02-04-2006, 09:05 AM
http://home.att.net/~jbaugher1/p47_4.html (http://home.att.net/%7Ejbaugher1/p47_4.html)

According to this source, the P-47D-27 was fitted with the R-2800-59 engine which has identical power output to the -63 engine used in the test aircraft, and differs only in that it is fitted with an improved ignition system.

As such the effect of increased manifold pressure upon power output should be identical, and therefore the P-47D in game should be slower than the razorback P-47 used for 70" Hg testing due to increased drag.

Viper2005_
02-04-2006, 02:43 PM
bump! I am interested in the input of the P-47 experts with regard to the source linked to above.

Slickun
02-05-2006, 05:40 AM
I gotta think that if the paddle blade prop was not used in a test it would not be mentioned, as it did not exist.

If the "new and improved" wide bladed prop WAS used, it almost certainly would be mentioned somewhere in the report.

Just speculation on my part.

Slickun
02-05-2006, 05:50 AM
My Dad flew, and loved, the P-47.

He liked it because it was so rugged and "honest". Things a pilot would love and cherish, but not necessarily tops on a General's list. He readily admitted the Mustang out climbed, outrolled, outturned, outzoomed (and both were great at it) and generally outran the Jug, as well as having as least as good dive characteristics. But in his world, that didn't outweigh the extra 2 .50's and a plane that would bring you home more often.

He agreed that the roll rate was good. He always talked about the Jug being a "Cadillac" versus other US types being "Chevy's". It was smooth and stable, with lots of amenities for a pilot.

He called the Mustang the "Spam Can" because of all the unfinished metal edges in it. You always wore gloves inthe Pony. It was also much more cramped. you wore the airplane, compared to the Jug, which was roomy.

It was hard to take a dump in the Mustang, or go wee wee. In the Jug it was much easier. And, on 8 hour missions, this was gonna happen sooner or later.

Bottom line in his book was that above 30,000 feet the Jug ruled the skies. At about 25,000 feet it began to get parity with the Mustang. Below that it was no contest.

Talking with Dad about aerial combat...if he was faster he basically said you would win. Period. He was of the opinion that dropping flaps to slow down was foolish, although many pilots did it successfully. Stay fast. If you overtake, go vertical.

I quizzed him pretty hard a few years ago about all this, and will post it sometime.

Professor_06
02-05-2006, 11:08 AM
Originally posted by Slickun:
My Dad flew, and loved, the P-47.

He liked it because it was so rugged and "honest". Things a pilot would love and cherish, but not necessarily tops on a General's list. He readily admitted the Mustang out climbed, outrolled, outturned, outzoomed (and both were great at it) and generally outran the Jug, as well as having as least as good dive characteristics. But in his world, that didn't outweigh the extra 2 .50's and a plane that would bring you home more often.

He agreed that the roll rate was good. He always talked about the Jug being a "Cadillac" versus other US types being "Chevy's". It was smooth and stable, with lots of amenities for a pilot.

He called the Mustang the "Spam Can" because of all the unfinished metal edges in it. You always wore gloves inthe Pony. It was also much more cramped. you wore the airplane, compared to the Jug, which was roomy.

It was hard to take a dump in the Mustang, or go wee wee. In the Jug it was much easier. And, on 8 hour missions, this was gonna happen sooner or later.

Bottom line in his book was that above 30,000 feet the Jug ruled the skies. At about 25,000 feet it began to get parity with the Mustang. Below that it was no contest.

Talking with Dad about aerial combat...if he was faster he basically said you would win. Period. He was of the opinion that dropping flaps to slow down was foolish, although many pilots did it successfully. Stay fast. If you overtake, go vertical.

I quizzed him pretty hard a few years ago about all this, and will post it sometime.

What an amazing Dad you have. There is P 47 message board for the old pilots that is fun to read. Maybe your Dad would like to visit some time
http://www.p47pilots.com/cfm_MessageBoards.cfm?pageMode...geboarddetail_id= 518 (http://www.p47pilots.com/cfm_MessageBoards.cfm?pageMode=READMSG&messageboardid=2&messageboarddetail_id=518)

Hub Zemke said the Jug was a better fighter than the 51 above 25,000ft. Speed was the main factor. The Jug rolled better the faster it went. Only .7% of jugs were lost to combat. This game wasnt ddesigned to showcase what the Jug did as a fighter. With no atmosphereic models over 30,000 ft and only arctic night sky over 15,000ft looks just goofy.

Zemke said the jug was best suited for ground attack but about 70% of aircraft loses were from small AA fire. I would think that would be 20mm AA guns.