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sureshot324
02-25-2004, 09:13 AM
What would fighters be like today?

sureshot324
02-25-2004, 09:13 AM
What would fighters be like today?

AWL_Spinner
02-25-2004, 09:15 AM
Awesome!

http://www.alliedwingedlegion.com/members/signatures/spinner_sig.jpg

Magister__Ludi
02-25-2004, 09:18 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by sureshot324:
What would fighters be like today?<HR></BLOCKQUOTE>

contrarotating prop pushers maybe?

carguy_
02-25-2004, 09:29 AM
If you hadn`t been born this thread would never appear here. http://ubbxforums.ubi.com/infopop/emoticons/icon_cool.gif

http://carguy.w.interia.pl/tracki/sig23d.jpg

Extreme_One
02-25-2004, 09:39 AM
If the word 'if' had never been invented...

S! Simon
'''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''''''''''''''''''''''''''''''''''''''''''''''' '''''
Download the RAF campaign folder here (http://www.netwings.org/library/Forgotten_Battles/Missions/index-9.html).

Download the USAAF campaign folder here (http://www.netwings.org/library/Forgotten_Battles/Missions/index-9.html). *NEW* Updated for FB 1.21

http://extremeone.4t.com/images/raf_sig.jpg

robban75
02-25-2004, 10:06 AM
Perhaps this plane would have been. The He P.1076. Estimated topspeed was 880km/h. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

http://www.luft46.com/heinkel/3bh1076.jpg

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

When it comes to aircombat, I'd rather be lucky than good any day!

Bansai Potato
02-25-2004, 10:10 AM
[QUOTE]Originally posted by Extreme_One:

If the word 'if' had never been invented...

_S! Simon_

But 'if' is the middle word in 'life' and where would what be without that....

:-)

http://homepage.hispeed.ch/Ede_EAF92/EAF/24890632.92EastIndiaSquadronpersonnel.jpg

Chuck_Older
02-25-2004, 10:17 AM
http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif there's no 'middle word' in life. That would make "l" the first word and "e" the last word in life. That would make "ontrac" the middle word in "contract". And that's just plain krazy

*****************************
from the Hundred Years war to the Crimea, from the lance and the musket and the Roman spear, to all of the men who have stood with no fear, in the service of the King~ Clash

Magister__Ludi
02-25-2004, 10:22 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by robban75:
Perhaps this plane would have been. The He P.1076. Estimated topspeed was 880km/h. http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

http://www.luft46.com/heinkel/3bh1076.jpg

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

When it comes to aircombat, I'd rather be lucky than good any day!<HR></BLOCKQUOTE>


Yes that would be one choice, here's a better drawing of it:

http://www.luft46.com/aoart/ao176-2.jpg


This FW looks more advanced:

http://www.luft46.com/rpart/rpfw3-2.jpg


Shinden is good choice too:

http://www.hobbyshop.ru/has/has09122.jpg

[This message was edited by Magister__Ludi on Wed February 25 2004 at 09:39 AM.]

Jirozaemon
02-25-2004, 10:22 AM
If my aunt had testicles, she would be my uncle...

Magister__Ludi
02-25-2004, 10:31 AM
And some ground pounders:

a Stuka evolution:

http://www.luft46.com/aoart/ao187-4.jpg


a FW attack plane:

http://www.luft46.com/gmart/gmj12-5.jpg


and a nice early B&V attack plane concept:

http://www.luft46.com/jhart/jh193-1.jpg

FW190fan
02-25-2004, 10:58 AM
Mr. Dornier's masterpiece would be more fully appreciated, along with the principle of center-line thrust:

http://www.luftwaffepics.com/LCBW4/Do335-A02-91s.jpg

http://www.luftwaffepics.com/LCBW4/Do335-A02-92s.jpg

http://www.luftwaffepics.com/LCBW2/Do335-65.jpg

http://people.aero.und.edu/~choma/lrg0645.jpg

Chuck_Older
02-25-2004, 12:32 PM
Magister-

how would that Stuka evolution's tail wheel ever touch the ground? That would give a whole new meaning to "tail-dragger".

*****************************
from the Hundred Years war to the Crimea, from the lance and the musket and the Roman spear, to all of the men who have stood with no fear, in the service of the King~ Clash

Zyzbot
02-25-2004, 02:48 PM
Don't forget this prop powered fighter...F-84H:

http://www.aerofiles.com/repub-xf84h.jpg

http://www.airwar.ru/image/i/xplane/xf84h-i.jpg

Magister__Ludi
02-25-2004, 03:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Zyzbot:
Don't forget this prop powered fighter...F-84H:

http://www.aerofiles.com/repub-xf84h.jpg

http://www.airwar.ru/image/i/xplane/xf84h-i.jpg <HR></BLOCKQUOTE>


How about this guy:
500km/h with engine at Idle:

http://jpcolliat.free.fr/xfv1/imagesxfy/xfy1_20.jpg

[This message was edited by Magister__Ludi on Wed February 25 2004 at 02:23 PM.]

Magister__Ludi
02-25-2004, 03:20 PM
Unfortunatelly the last two do not really qualify because they are still powered by a jet turbine (even if turboprop) -- IIRC both are powered by the same engine (in F-84H case it had a lot of troubles).

Zyzbot
02-25-2004, 03:22 PM
But in our fantasy world they would be prop planes!
http://aerostories.free.fr/reaction/xf88b.JPG

JR_Greenhorn
02-25-2004, 03:25 PM
Not all of these are "what ifs;" the J7W1 Shinden actually flew, the F-84H is clearly composite-powered, and even if authenticity can be assumed, the FW attack plane from the grain-of-salt Luft 46 collection borrows heavily from a Fokker design that flew (the Japanese had a mockup of a similar design).

DaBallz
02-25-2004, 03:25 PM
http://www.aviation-history.com/engines/xr-7755.jpg] (http://www.aviation-history.com/engines/xr-7755.jpg)

the Lycoming XR-7755 shows where piston engines were going.

Da...

Magister__Ludi
02-25-2004, 03:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Zyzbot:
But in our fantasy world they would be prop planes!
http://aerostories.free.fr/reaction/xf88b.JPG <HR></BLOCKQUOTE>

Ok then here's another one:

http://prototypes.free.fr/fr1/images/xp81_03.jpg

Zyzbot
02-25-2004, 03:28 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JR_Greenhorn:
Not all of these are "what ifs;" the J7W1 Shinden actually flew, the F-84H is clearly composite-powered, and even if authenticity can be assumed, the FW attack plane from the grain-of-salt Luft 46 collection borrows heavily from a Fokker design that flew (the Japanese had a mockup of a similar design).<HR></BLOCKQUOTE>

----------------------------------------

The XF-84H "thunderscreech" was real all right:

http://www.wpafb.af.mil/museum/annex/an48.htm

Magister__Ludi
02-25-2004, 03:32 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DaBallz:
http://www.aviation-history.com/engines/xr-7755.jpg

the Lycoming XR-7755 shows where piston engines were going.

Da...<HR></BLOCKQUOTE>

Yes, this was the problem with the last generation of engines they had huge frontal area and they were very heavy. Turbines of the same power were much smaller. Most probably there would never be a Jumbo airliner today with prop engines only, and no cheap airfares http://ubbxforums.ubi.com/infopop/emoticons/icon_frown.gif that would really suck, that's why I really like jet engine, they are really simple and they can reach increadible power ratings with reasonable development effort and operation costs.

JR_Greenhorn
02-25-2004, 03:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DaBallz:
the Lycoming XR-7755 shows where piston engines were going.<HR></BLOCKQUOTE>In the case of bombers perhaps (B-36), but for fighters I would beg to differ. I think that engine would be nearly prohibitive of fighter applications, due to its excessive diameter,

On the other hand, the saw-production R-4360 Wasp Major is a much more innovative design that never showed its true potential in figher planes thanks to the upcoming jets. Of all of the a/c engines designed/used during WWII, it is my opinion that the R-4360 is the best.

Tooz_69GIAP
02-25-2004, 03:36 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>how would that Stuka evolution's tail wheel ever touch the ground? That would give a whole new meaning to "tail-dragger".<HR></BLOCKQUOTE>

As far as I am aware, this evolution was a design with fully retractable gear, and the tail section had the ability to "pivot" depending upon the situtation. In flight, the tail would be pointed downward, as it is (I think this improves aerodynamics??), and improves dive performance I think, and when landing, the pilot would swing the fin to "top" position so that he wouldn't wreck the tail.

Was supposed to be a damn fast aircraft, but the war ended while still in testing.

whit ye looking at, ya big jessie?!?!

http://www.baseclass.modulweb.dk/69giap/fileadmin/Image_Archive/badges/69giap_badge_tooz.jpg
Za Rodinu!

JR_Greenhorn
02-25-2004, 03:42 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Zyzbot:
The XF-84H "thunderscreech" was real all right<HR></BLOCKQUOTE>I didn't mean to challenge whether it was real or not (I've heard of it too), I just meant that it wasn't a pure propellor aircraft. That attribute is betrayed by the jet nozzle at the end of its tail. Sorry for the confusion.



Another engine type that didn't see the development it could have at the time was turboprops. There was a twin-turboprop version of Gloster's Meteor flown, and the Westland Wyvern was not successful due to its use of the lesser of two engines availible. Although much later, the PA-48 Enforcer is another example of the validity of turboprop fighers.


I also find the earlier "motor-jets" interesting--that is: jets with piston-engine-driven compressors. I know the Soviets were working on these, and I think the Italians may have been as well.

Zyzbot
02-25-2004, 04:05 PM
The XF-84H used an Allison XF-40-A-1 turboprop engine in a modified F-84 fuselage.

Don't know if it is true but "they" claim it was the fastest single engine propellor driven aircraft.

Zyzbot
02-25-2004, 04:37 PM
http://www.geocities.com/unicraftmodels/germ/dbf/dbf.jpg

noshens
02-25-2004, 05:06 PM
The russian and ukrainian companies still build lots of different kinds of passenger and cargo airplanes powered by propeller. Look for antonov designs.
note propeller, does anyone know why are they like this?

http://www.aeronautics.ru/img002/an70-fly-by01.jpg

http://www.flightsim.krsk.ru/p_galary/AN70.jpg

Zyzbot
02-25-2004, 05:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by yay1:
The russian and ukrainian companies still build lots of different kinds of passenger and cargo airplanes powered by propeller. Look for antonov designs.
note propeller, does anyone know why are they like this?

http://www.aeronautics.ru/img002/an70-fly-by01.jpg <HR></BLOCKQUOTE>

Yes...and don't forget the C-130

The C-130 has been in continuous production since 1954, and over 2,100 Hercules have been built for 64 countries. The improved C-130J entered production in 1997.

Zyzbot
02-25-2004, 05:19 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by yay1:
The russian and ukrainian companies still build lots of different kinds of passenger and cargo airplanes powered by propeller. Look for antonov designs.
note propeller, does anyone know why are they like this?

<HR></BLOCKQUOTE>
According to one source:


"...these are designed to offer very high speed combined with low fuel consumption. The Russian developed SV-27 all composite propellers are highly swept and are claimed to have a 90% efficiency in cruise, at near jet speeds.

Takeoff and landing speeds are also lower thanks to the propfans, while the An-70's ability to fly from relatively short fields means it can operate from 80% of all ClS airstrips, allowing shorter journeys and greater point to point flights."

JR_Greenhorn
02-25-2004, 05:20 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by yay1:
note propeller, does anyone know why are they like this?<HR></BLOCKQUOTE>They just look like the large paddle-type blades in a contra-rotating arrangement; its kind of har to count the blades in these photos, looks like 4 each. Several aircraft tested various contra-rotating props in WWII, among the more notable ones is the Martin Baker MB.5. Beyond that, I don't know for sure what the advantages are. They probably cancel torque moments, but there must be further benefits to justify the complexity.

ASH at S-MART
02-25-2004, 05:33 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by sureshot324:
What would fighters be like today?<HR></BLOCKQUOTE>They would be like a modern jet with missles.. minus the jet and the missles

ASH at S-MART
http://www.thecobrasnose.com/images4/brucecampbellSMart.jpg

DaBallz
02-25-2004, 05:52 PM
C-130 has been in continuious production for 50 years.
Not bad for a large plane?


This copied from the "Avaitaion Zone"

Background

On 23 August 1954, the YC-130A Hercules (#53-3397) made its maiden flight at Burbank, California. Only the two YC-130 prototypes (#53-3396 was the first built) were assembled at Lockheed's "Skunk Works" plant in Burbank, while more than 2,000 subsequent aircraft have been built in Marietta, Georgia.

The initial production model was the C-130A, with four three-bladed Allison T56-A-9 turboprops. A total of 219 were ordered. The first C-130A (#53-3129) flew on 7 April 1955 and deliveries began in December 1956. Two DC-130As (originally GC-130As) were built as drone launchers/directors, carrying up to four drones on underwing pylons. All special equipment was removable, permitting the aircraft to be used as freighters (accommodating five standard freight pallets), assault transports, or ambulances.

Five decades have elapsed since the Air Force issued its original design specification, yet the remarkable C-130 Hercules remains in production. The venerable "Herk" is the most successful military transport since the Douglas C-47 and has accumulated over 20 million flight hours. More than 900 C-130s and derivatives have been delivered to the U.S. Air Force during the past 30 years. The aircraft type currently serves in over 60 foreign countries and is expected to remain in production well into the 21st century.

U.S. Air Force

One final note, The C-130 is unique in it can be
called a pig and not be insulted.
We C-130 mech's all called em our pigs.

Da...

Magister__Ludi
02-25-2004, 06:21 PM
Yes indeed, Herc is one great plane with props.
Another that I can think of is Tu-95/142 Bear bomber or the huge cargo plane An-22 (same engines with Tu-95).

Ob.Emann
02-25-2004, 06:36 PM
Let us not forget this beauty:

Messerchmitt Me-329

http://www.luft46.com/mess/3bm329.gif

http://www.luft46.com/images/me329-7.jpg

Der Oberst (PROMOTION!)

Flamin_Squirrel
02-25-2004, 06:51 PM
Appologies if im patronising... but you guys do realise that turboprops are essentialy jet engines powering a properller right? Planes like the C130 are powered by these. It might have propellors, but the engine is very different from the piston engines planes i presume we're talking about here.

JR_Greehorn - you're absolutely right about canceling torque. Not such a issue on multi-engine planes as im sure you can imagine. As for single engine fighers, it was a big problem. Just think, late war Bf109's would flip onto their back on the ground/low speeds if you simply looked at them fuuny. I think Mk2 Tempests had engines generating almost 3000hp... so there was a limit how powerful you could feasibly get before the plane becomes unflyable due to the increase in torque without something to counter act it.

One thing I think about the direction post war piston engined planes were going in, was getting more ugly! lol

Magister__Ludi
02-25-2004, 06:53 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JR_Greenhorn:
I didn't mean to challenge whether it was real or not (I've heard of it too), I just meant that it wasn't a pure propellor aircraft. That attribute is betrayed by the jet nozzle at the end of its tail. Sorry for the confusion. <HR></BLOCKQUOTE>

Turboprops have a shaft power but also exhaust thrust. In the case of early turboprops exhaust thrust can be very important, because most of those designs converted around half the engine thrust in shaft power. This happend because early axial compressor jets had a very narrow operating turbine rpm range. Engineers had difficulties gearing the turbine shaft to a propeller that normally has to have large rpm range. This is why first turboprop was done on a cetrifugal compressor jet engine (that on Meteor).


<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>"Another engine type that didn't see the development it could have at the time was turboprops. There was a twin-turboprop version of Gloster's Meteor flown, and the Westland Wyvern was not successful due to its use of the lesser of two engines availible. Although much later, the PA-48 Enforcer is another example of the validity of turboprop fighers.<HR></BLOCKQUOTE>

Meteor with those little turboprops was very much underpowered, it was mounted only to prove that turboprops are practical. Westland Wyvern is a controversial aircraft. It is one of the few british design that I really like (british designs seem that you either love them or hate them) on paper it seems one capable ground attack aircraft, and pilots that flew it in combat seemed satisfied with the type. In peace time however it was a difficult plane to fly on carrier deck (it is huge!). The thing with the engine I don't really buy. Indeed the RR engine was more advanced, but in production Python was more powerful than RR Clyde. I think the reason why it was abandoned was that at the beginning of the '60s such type of planes seemed obsolete (which of course was not true).

I have to put a pic with Wyvern, I'm sorry http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif

http://www.challoner.com/aviation/quiz/pix/38-33.jpg

and the turboprop one:

http://www.aero-art.com/cartespo/monheli/wyvern.jpg


<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>I also find the earlier "motor-jets" interesting--that is: jets with piston-engine-driven compressors. I know the Soviets were working on these, and I think the Italians may have been as well.<HR></BLOCKQUOTE>

Actually motorjets are the first jets that flew, in 1910 Coanda (the guy with the Coanda effect) flew one to a crash http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif (he escaped unharmed)

http://www.allstar.fiu.edu/aero/images/Coanda_1.gif

[This message was edited by Magister__Ludi on Wed February 25 2004 at 06:04 PM.]

Magister__Ludi
02-25-2004, 07:08 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Flamin_Squirrel:
Appologies if im patronising... but you guys do realise that turboprops are essentialy jet engines powering a properller right? Planes like the C130 are powered by these. It might have propellors, but the engine is very different from the piston engines planes i presume we're talking about here.
<HR></BLOCKQUOTE>

Yes, we are realizing that turboprops are not piston engines, also that piston engines of 15000HP like NK12 turboprop would not be feasible. But since turboprops use props they are somehow similar, in that their thrust varies a lot with speed, in contrast with pure jets. Turbofans are also similar with turboprops in this respect and if we compute the shaft horsepower from static sea level thrust for one recent big turbofan (like GE-90) we'll get power ratings around 40000HP: now that's something http://ubbxforums.ubi.com/infopop/emoticons/icon_eek.gif

[This message was edited by Magister__Ludi on Wed February 25 2004 at 06:41 PM.]

DaBallz
02-25-2004, 07:34 PM
A quick look at the early history of turboprop
powered planes shows that the reliability of the
engines determined the success of the aircraft.
Notable failures were the Convair R3Y Tradewind flying
boat and the Douglass C-133.

Any and all planes powered by the Allison T-40/T-38
engines failed. While some, such as the R3Y Tradewind
were excellent designs the engines were total failures.

In the case of the C-133 it was the Curtiss Electric props
on the otherwise excellent P&W T-34s.

There are two basic types of turbo prop powerplants.
Single spool and twin spool. Both can be of either
axial or centrafugal design.
The excellent and super reliable Allison T-56 series (C-130)
is of the single spool design.
Single spool engines must run at constant speeds, +-3% in the
case of the T-56.
Later designs are of twin spool design. Twin spool engines are co-axial
and the inner section can remain at 90-110% while the
turbine/power section can vary widely in speed without
trouble.

Twin spool engines tend to be more efficent than single spool.
Single spool tend to be lighter, and because they were first
and the T-56 is ultra reliable, they will be around for
another hundred years.

The new C-130J is powered by a Rolls Royce engine of twin spool
design. The inner section can run at 90% rpm while the prop
is feathered and turning a few hundred rpm!

Oh yes, in rebuttal to the comment about the unrecovered energy
exiting the tail pipe as thrust... In tech school we
were taught that a T-56A-15 was rated at 4,900ESHP.
That's 4,100hp at the shaft and the remaining 800hp was
thrust. That's 80% recovered heat energy. Not bad for
an early 1950's design.

Da...

Magister__Ludi
02-25-2004, 07:58 PM
Back to the last huge piston engines.
This one is a real treat: 4000HP 4 row radial, relatively small frontal area. Abandoned in '43 because the company started the work on a jet engine of a larger shaft power than this one: almost 4000KW.

the awesome BMW-803:

http://www.bmw.com/eheritage/COM/en/1943/innovations/media3/FF691.jpg

tenmmike
02-25-2004, 08:49 PM
http://www.aviation-history.com/engines/xr-7755.jpg here you go This 36 cylinder engine was destined to be the largest reciprocating engine ever built for aircraft use. The displacement was 7,755 cubic inches. When compared to Lycoming's largest production engine in production today which displaces 720 cubic inches, it was more than 10 times larger!

This huge engine was 10 feet long, 5 feet in diameter and weighed 6,050 pounds. It produced 5,000 HP at 2,600 RPM, and the target was 7,000. It used 580 GPH of av gas at the 5,000 HP rating.

There were nine overhead camshafts which could be shifted axially for METO power in one position and cruise at the other. Two great shafts emerged for coaxial propellers, and there was a two speed gear-change box between the crankshaft and the propeller shafts.

Development of the XR-7755 began at Lycoming in Williamsport in the summer of 1943. With the end of World War II in 1945, the military no longer had a need for an engine of this size, and development of the XR-7755 stopped at the prototype stage.

During those years, Lycoming put together a team, under the leadership of VP Engineering Clarence Wiegman, to develop this super-size engine.

The engine now resides at Silver Hill of the Smithsonian Institute.
http://images.ar15.com/forums/smiles/anim_50cal.gif U.S INFANTRY 1984-1991

ASH at S-MART
02-25-2004, 11:26 PM
http://www.genemay.org/images/misc-pix/xb42-1.jpg
http://www.daveswarbirds.com/usplanes/photos/xb-42tail.jpg
http://home.tiscalinet.ch/u.bopp/images/w006.jpg
http://northrop.host.sk/images/northrop_xb-35.jpg
http://northrop.host.sk/images/XB-35_10.jpg
http://northrop.host.sk/images/b35-3.jpg
http://northrop.host.sk/images/XB-35_20.jpg
http://northrop.host.sk/images/xb-35-earlyfrt.jpg
http://www.yourzagi.com/history/xb-35props.jpg
http://www.yourzagi.com/history/xb35-waiting.jpg

ASH at S-MART
http://www.thecobrasnose.com/images4/brucecampbellSMart.jpg

WUAF_Badsight
02-26-2004, 12:09 AM
ok first of all if there were no jet propulsion then the world would be a bigger place due to Global travel taking so long

second (& this is important for Fighter A/C) 550 Mph is the barrier for single motor pulling prop planes

sure you can increase the climb speed but you wont get a single prop plane in pulling configuration going much over 550 Mp/H

pinche_bolillo
02-26-2004, 01:33 AM
if jets and missles were never invented everybody would be using La-7s or Ki-84s :O

JR_Greenhorn
02-26-2004, 01:49 AM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by WUAF_Badsight:
550 Mph is the barrier for single motor pulling prop planes

sure you can increase the climb speed but you wont get a single prop plane in pulling configuration going much over 550 Mp/H<HR></BLOCKQUOTE>But if everything else is limited to the same top speed, the ability of a fighter to climb like an angry monkey is of paramount importance.



Thoughts on contra-rotating propellors:
Surely propellors in this configuration cancel each others torque moments, but the torque moment of the engine itself still remains, right? I suppose the magnitude is small enough to be managable. Is the airflow through the propellors (that which the airframe itself encounters) any different than it would be with conventional propellors?


Thoughts on engine torque:
Somebody mentioned the later Bf 109's ability to roll onto its backside on the deck if subjected to ham-fisted throttle imputs. The problem was worse with the Czech Jumo 211F-powered 109s with their large paddle-type propellors. I have read of similar behaviour on the part of the F4U, what with it wearing one of the larger diameter propellors fitted to fighters.

Also mentioned was the prodigious 3000-odd hp produced by the Napier Sabre in the Tempest. However, conspicuously absent was comments on this aircrafts tendencies of the same. Could it be due to this particular engine's slightly higher operating rpm that engine torque is actually reduced, in turn reducing torque moments generated? If jets didn't take over, is it reasonable to consider increasing operating rpm to achieve greater horsepower ratings at reduced torque levels could help reduce negative torque moment effects on the airframe?


Thoughts on the BMW 803:
It appears to have 28 cylinders, what do you suppose they displace? Also, the engine appears to be liquid cooled, although the jackets look somewhat primative (fabbed, not integrally cast). Were there any aircraft slated to use this engine? What years are we talking here?


Thoughts on large, liquid cooled radials:
Why?

DaBallz
02-26-2004, 04:04 AM
The reasoning for contra rotating propellers is
the need for absorbing greater amounts of power.
The canceling of torque is a side bennafite.

Propellers had to grow more blades and get bigger
to use all the power generated in the last generation
of prop planes. Contra rotating props allowed
the power to be spread over more blades.
In fighter applications the torque was negated
and provided obvious bennifites.

The truth is that for all out speed the smaller
the blade count the better.
But if you feed to much power into a prop
it stalls like an over loaded wing!
After all a prop blade is just a wing.
When a prop stalls the RPM surges and "runs away".
Now you are not going anywhere.
At very high speeds this is not a problem
and the extra blades become a liability.

If you are having a tough time understanding
why fewer blades is better for high speeds, just
think monoplane VS Biplane. Fewer wings
means less drag.
Same thing for a prop.

Da...

J_Flyer
02-26-2004, 08:57 AM
You're ALL wrong...

it would be a Tutor with a couple o' machine guns strapped to the bottom with a bit of duck tape... http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif

The propellor is just a big fan to keep the pilot cool.. when it stops you can see
the pilot start sweating!

A good landing is one you can walk away from...A great landing is one where they can use the plane again afterwards!!!
http://www.jhsw05251.pwp.blueyonder.co.uk/32F%20Website/Flying%20&%20Gliding/Powered%20Flying/Tutor.jpg

The legendary plane of the UK air cadets. The tutor!

Dmitri9mm
02-26-2004, 09:09 AM
Tink about this one:
What if hypothetical questions did not exist?

Magister__Ludi
02-26-2004, 12:03 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Dmitri9mm:
Tink about this one:
What if hypothetical questions did not exist?<HR></BLOCKQUOTE>


Thogh this is a forum of people bored by jets, I'd say that early jets are fascinating. So much was achieved with very little. Early jets have the subtlety of a kitchen oven http://ubbxforums.ubi.com/infopop/emoticons/icon_biggrin.gif a few fuel guzzling cans with an impeller in front and another at the end, no gears, no liquid cooling, not even oil cooling, just three moving pieces tighlty connected (no gears) doing all the work. As long as you keep the flame burning (and this was difficult back then http://ubbxforums.ubi.com/images/smiley/16x16_smiley-tongue.gif) you have a powerplant that throws everything else into obsolescence. Amazing!

JR_Greenhorn
02-26-2004, 02:03 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DaBallz:
The reasoning for contra rotating propellers is...<HR></BLOCKQUOTE>Thanks for the informative post.

What are the advantages and liabilities of running a 5-blade propellor (like late Mk. Spitfires) vs. 2 3-blade contra-props?

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
I'd say that early jets are fascinating.<HR></BLOCKQUOTE>
I agree wholeheartedly, but I also like piston engines very much, so I can't help but feel like their development was curtialed by the emergence of turbojets. The leading edge of piston engine development was handed off to motorcycle racing immediately postwar, then again to auto racing (F-1) in the eighties. Its interesting to consider where psiton engines would be if afforded another decade of aircraft development.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
...no liquid cooling, not even oil cooling...<HR></BLOCKQUOTE>Are modern turbojets liquid or oil cooled? I wasn't aware that any were, but I don't keep up.
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
...you have a powerplant that throws everything else into obsolescence. Amazing!<HR></BLOCKQUOTE>In the skies, at least. Personally, I would like to see the development of ground-dwelling turboshaft engines expanded. I like the concepts in VATN and differentially-geared designs.

Magister__Ludi
02-26-2004, 02:13 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JR_Greenhorn:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
...no liquid cooling, not even oil cooling...<HR></BLOCKQUOTE>Are modern turbojets liquid or oil cooled? I wasn't aware that any were, but I don't keep up. <HR></BLOCKQUOTE>

No, no. All I wanted to say was that first jet turbines were air cooled, like radials, but they also did not have oil cooling.


<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
...you have a powerplant that throws everything else into obsolescence. Amazing!<HR></BLOCKQUOTE>In the skies, at least. Personally, I would like to see the development of ground-dwelling turboshaft engines expanded. I like the concepts in VATN and differentially-geared designs.<HR></BLOCKQUOTE>

Sure, I was talking about piston engines becoming obsolete as an airplane powerplant.

JR_Greenhorn
02-26-2004, 02:27 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Magister__Ludi:
first jet turbines were air cooled, like radials<HR></BLOCKQUOTE>Actually one of the reasons I find turbine engines facinating is that they are self cooled by the working fluid, provided the flowrate is high enough, where radials just reject heat into the ambient from simple sinks. I'm sure you are well aware of this, but I find it an interesting feature, so I thought I'd clarify.


Back to speculation on piston engine development, it is my opinion that had these engines been allowed further development, there would have been more and more close cowled, fan cooled radials used. This arrangement seems to strike the best compromise among frontal area, power production, cooling capabilities, and cooling- and packaging-associated drag. It seems that in any other application (land, sea, etc.) liquid cooling is superior, unless cost is a major consideration.

Flamin_Squirrel
02-26-2004, 02:48 PM
As engines got more powerful you needed a prop that could bite on enough air so you could get all the power out without the rpm going though the roof. To do this you can add more blades, make the blades fater, or make them longer.

There are obvious limits to how many, or how wide you make the blades. You cant make the blades too long either, because the longer the blades the faster the tip goes. Make them long enough and the tip will break the sound barrier and you're in trouble.

GAU-8
02-26-2004, 03:28 PM
we would have thrust vectored propped, carbon fiber bodied, high power to weight ratioed, chipped, modded, turbo supercharged, "rice" aircraft...with guns.

aye, im in love......

GAU-8
02-26-2004, 03:31 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Make them long enough and the tip will break the sound barrier and you're in trouble.<HR></BLOCKQUOTE>

just curious..why? other than sound pollution?

is there a LAYMANS explanation to that... or do i have to bone up on some study?

JorBR
02-26-2004, 03:36 PM
The future will be like that http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif

http://www.todo-aviones.com.ar/rusos/tupolev95-142/tu95-2a.jpg

"Never wrestle with a pig; you both get dirty but the pig enjoys it!"

JR_Greenhorn
02-26-2004, 03:40 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JorBR:
The future will be like that http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif<HR></BLOCKQUOTE>That looks like a Bear of a plane!

JorBR
02-26-2004, 03:52 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JR_Greenhorn:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by JorBR:
The future will be like that http://ubbxforums.ubi.com/images/smiley/16x16_smiley-happy.gif<HR></BLOCKQUOTE>That looks like a Bear of a plane!<HR></BLOCKQUOTE>

With which looks like a Bear of a Engine http://ubbxforums.ubi.com/images/smiley/16x16_smiley-very-happy.gif

Kuznetsov NK-12 turboprop (14,795hp http://ubbxforums.ubi.com/images/smiley/16x16_smiley-surprised.gif)

"Never wrestle with a pig; you both get dirty but the pig enjoys it!"

DaBallz
02-26-2004, 03:53 PM
The 5 bladed Rotol prop on a Spit has the advantage
of great blade area, but it's wood! The blades
are a bit thick.

Advantages, light weight and good blade area.

Disadvantages, thick blades adversly effecting
top speed and heavy torque reaction.
Also i would think the wood blades would break
up in a nose over reducing the chance of
engine/gearbox damage.

The 6 bladed contra rotating prop used on the
Seafires was likely superior.
But I would prefer the light weight prop
in a dogfight.

There seems no limit on the number of blades.
there are 8 bladed props being tested on
the C-130J. The J model presently has 6 bladed props.

Da...

Flamin_Squirrel
02-26-2004, 05:59 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by GAU-8:
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> Make them long enough and the tip will break the sound barrier and you're in trouble.<HR></BLOCKQUOTE>

just curious..why? other than sound pollution?

is there a LAYMANS explanation to that... or do i have to bone up on some study?<HR></BLOCKQUOTE>

To be perfectly honest im not 100% on the reason. I know that the transonic region (from aprox mach 0.9 to 1.1) produces alot of drag. This could well be the problem, as it might waste any extra power going supersonic into overcoming the drag.

Also, unlike a modern jet which can just power though above mach 1.1, even if you could power the blades though the sound barrer, there would be a slower region of the blade in this high drag situation.

DaBallz
02-26-2004, 06:59 PM
Good explanation, the prop will always have a portion
of it in the trans sonic speed range, very high
drag and those nasty shock waves prevent you
from powering through.
Even if you could, the drag in the supersonic
enviorment is roughly double that of the subsonic regime.
Then if you had the power you now have those
nasty intermittent shock waves pounding
your airframe into junk.
Not to mention it would be so loud as to wake up the dead.

Keep in mind that even Jets don't like supersonic
airflow. They require variable or restricted
inlets to keep the inlet air under the speed of sound.

The only way I could see a prop drive a plane
at supersonic speeds is with a ducted prop/fan.
But it would require massive power.
again, it is at best a long shot.

Da...

JR_Greenhorn
02-26-2004, 07:06 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Flamin_Squirrel:
Also, unlike a modern jet which can just power though above mach 1.1<HR></BLOCKQUOTE>I don't think thats quite accurate. Even modern jets have to slow the incoming airstream to subsonic speeds before it encounters the compressor. The engine would flame out otherwise.

In theory, one could devise a way to do a similar effect for a propellor (say in a pusher configuration), but the diameter is just too large, and I doubt the propellor would make significant thrust after all the trouble.

Of course, all this is for airstreams supersonic realative to the aircraft. As for propellor tips moving supersonic, I don't think turbojet compressors reach those speeds either. At any rate, I don't know why thats the limit, just that it is.

Flamin_Squirrel
02-26-2004, 07:19 PM
Yeah jets have to slow the air down for their engines, but i actualy ment the airframe its self, not its engines. Once the aircraft is traveling above mach 1.1, it no longer has to push though the high drag tansonic region (Appart from in the engine intakes of course, but this would actualy be beneficial in slowing the air down before reaching the compressor). A prop however would, because no matter how much faster than the speed of sound the tip goes, there will always be part thats stuck in the high drag speed range.

VonShlagnoff
02-27-2004, 01:24 PM
Ok then my two pence worth, and before you ask I work on C130 engines for the RAF.

First point, the highest speed that airflow can be presented to any compressor is about 350mph, this is why variable geometry intakes are required for highspeed flight(super/trans sonic), if the aircraft flys below this speed then you will find that the intake will open out inside the aircraft and slow the airflow like that.

Second point, the net thrust produced by the gas core of any turboprop engine is only about 10 percent, everything else is removed from the gas flow to turn the prop/gearbox.

Third point, turbo prop engine power is measaured as tourque not rpm, and the thrust is controlled by the blade angle, so the fuel flow/tourque will increase/decrease to compensate for changes in blade angle.

Fouth point, once you are in supersonic flight you still have the shockwaves to contend with its just that they are behind the aircraft. Most ww2 pilots that suffered controll reversal near the speed of sound did so because the shock wave was sat on their control surface making it impossible to move and causing the airframe to flex.

Point five, there are 3 types of turbo prop engine, the direct coupled where the prop is bolted to the compressor, the reduction gearbox, where a turbine not connected to the compressor drives the prop/gearbox, and the free turbine where the prop has its own turbine and no gear box, this is the most efficient as the prop can find its own speed independently of the gas core. Turbofan engines are basically the same its just that the prop sits in a tube, and turbo shaft engines eg helicopters/tanks/trains work the same its just that their gearboxes drive other stuff.

If jets and missiles were not invented the modern A/C would sound so cool, but to be most maoeverable they would look kinda strange. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

DaBallz
02-27-2004, 03:07 PM
The info I have says around 550mph max at the inlet for a jet, but the point has been made.

I have never seen a turboprop where the prop
is attached directly to the compressor shaft
without gear reduction. That would be one
very fast turning prop.

Turbo shaft is twin spool. The primary
advantage to twin spool is that you can vary
the power shaft speed without flaming out the
engine.
Single spool engines must maintain constant speed.
Modern turbo props with twin spool power sections
have tachs and torque meters. As you pointed out the
prop can find it's own speed independant of the
"core".

The older T-56A-7 thru 16 series had RPM in %
only along with torque meters. They are sinsle shaft/spool.

All turbofan engines are twin spool. Even modern
turbojets can be twin spool. The highly successful
P&W J-79 series is an example.

Da...

JR_Greenhorn
02-27-2004, 05:12 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by DaBallz:
Turbo shaft is twin spool. The primary
advantage to twin spool is that you can vary
the power shaft speed without flaming out the
engine.<HR></BLOCKQUOTE>There have been single spool turboshaft engines. Rover, I think it was, had one, and it didn't work very well (obviously). On a land-based application, the single spool turboshaft needed elaborate clutching and gearing to operate.

I have seen a shematic of a differentially-connected turboshaft engine for ground applications. Compressor and turboine are on separate shafts, but these shafts are connected through a differentail that also feeds the output shaft. The idea was that the gearing would attempt to keep the compressor at top speed whenever possible to maximize efficiency and "throttle" response. I don't know if such a concept has seen any prototypical development, but I find it interesting none the less.

hobnail
02-27-2004, 05:55 PM
The CAC CA-15

http://users.chariot.net.au/~theburfs/images/ca15.jpg (http://users.chariot.net.au/~theburfs/ca15MAIN.html)

http://users.on.net/apoulos/webbanner.jpg (http://www.jg11.com)

Magister__Ludi
02-27-2004, 05:57 PM
This is an interesting thread, keep it comming http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif