# Rear-Engine Pusher Fighter?



## gjs238 (Apr 27, 2011)

Were there any?
I'm thinking a layout more like a jet aircraft, with the engine in the rear and the cockpit more forward.
Cooling could be with a P-51 type radiator scoop.


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## gjs238 (Apr 27, 2011)

OK, I see the XP54, XP55, XP56.


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## mikewint (Apr 27, 2011)

The only one I know of is the Do335 and that was toward the end of the war with only about 20 having been delivered to combat units and it had a front puller engine in addition to the rear pusher.
others here may know of more


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## tomo pauk (Apr 27, 2011)

Saab 21, image from Wikipedia. Note the coolers' location.

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## gjs238 (Apr 27, 2011)

Oooh-la-la. Nice find!


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## mikewint (Apr 27, 2011)

I was thinking WWII but your original post did not specify that, nice find on the Sweatish 21 (Too bad its not a 13)


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## davebender (Apr 27, 2011)

Dornier produced several tandem engine seaplanes so it's no surprise they chose a similiar arrangement when RLM finally agreed to fund the Do-335.

Does Saab have a history of producing rear engine aircraft?


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## tyrodtom (Apr 27, 2011)

Most experimented with them.
America had the XP-54, 55 and 56, by Vultee, Curtiss, and Northrop. Japan had the Kyushu J7W. Italy had the Ambrosini SS.4. But Sweden is the only country that put a pusher fighter aircraft into service in the WW2 era. They later converted the same design to jet power.


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## A4K (Apr 27, 2011)

Kyushu J7W1 Shinden

Shinden


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## T Bolt (Apr 27, 2011)

Just had to throw that one in.


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## The Basket (Apr 27, 2011)

Saab 21 looks good. But how does a pilot bail out with a blender churning behind him?

I hope the Saab had an ejection seat or the pilot was in for the chop.


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## Shortround6 (Apr 27, 2011)

Some of the pusher planes had schemes to jettison the prop before the pilot bailed out. I may be wrong but I believe the XP-56 had two turns of "det cord" around the reduction gear case on the engine to 'ensure' propeller separation.


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## tyrodtom (Apr 27, 2011)

The Saab 21 had a ejection seat.


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## Rivet (Apr 27, 2011)

Two pusher prop designs that never made it into operational usage might be the Curtiss XP-55 Ascender and the Japanese canard elevator Kawanishi Hein Shinden.


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## gjs238 (Apr 28, 2011)

The pusher layout seems to permit concentrated firepower in the nose.


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## jjp_nl (Apr 28, 2011)

How about the Fokker D.XXIII...not strictly a pusher fighter but still an interesting and obscure find imho. One prototype flew prior to The Netherland being overrun by the Germans 1940.


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## tomo pauk (Apr 28, 2011)

Plane of such an layout with 2 x Jumo 210 or with two Kestrels would've been interesting addition for many airforces of pre/early WW2. The scaled up version with Merlin/DB601-603/Allison/Klimov makes a potent warbird.

Or replace front engine with 4 x 20mm (or a pair of 37/40mm), and rear engine with something around 1500HP, give or take 200 HP. Okay, we end up at Saab 21


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## gjs238 (Apr 28, 2011)

As far as the two-engined bird, I wonder if that could develop into the night fighter you queried in another thread.


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## jjp_nl (Apr 28, 2011)

gjs238 said:


> As far as the two-engined bird, I wonder if that could develop into the night fighter you queried in another thread.


 
Not sure what you mean....

But, not intentionally no, but by request I could take it into that direction if it suits you


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## davebender (Apr 28, 2011)

Front engine fighter aircraft would receive 1,500+ hp engines at the same time. How would a rear engine fighter stack up compared to the Fw-190, F4U, Spitfire IX, Me-109G6 etc.?


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## Shortround6 (Apr 28, 2011)

Well, considering that a large number of paper projects never made it to sheet metal, and only the Saab made it into production may tell us something.

1. In theory the pusher had to contend with a disturbed airflow hitting the propeller. 
2. With no prop in front armament was easier to layout/concentrate
3. Without going to a twin boom layout like the Saab arranging for control surfaces and stability was a problem.
4. Going to a twin boom layout doesn't really decrease drag over a normal fuselage.


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## tomo pauk (Apr 28, 2011)

In German use, such a configuration allows for, say, 3-4 x 20mm, or 2-3 x MK 108, or 2 x MK0103, or 1-2 x 37mm + MGs. So it's a bomber destroyer, or/and tank buster that can both do the job fight back @ Allied fighters.
Vs. Spit MkV through -IX, it allows for a central weapon battery, eg. 3-4 x 20mm (fighter), or 1-2 x 40mm + MGs; all 20mm yields far better firepower than what Spits have had, while the 40mm variant has less better accuracy than wing mounted guns of Hurri IID. 
As for US use, V-1710 needs turbo to to have decent HP (1425/1600 in 1943), or two stage compressor (like P-63 had); central battery allows for more accurate/'better' fire (for same number of MGs), or a still decent punch with one or two MGs less. Dunno how well R-2800 would've fared at aft hull, cooling-wise.

Allied planes could've picked some roll rate, with MGs relocated almost to centreline.


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## gjs238 (Apr 28, 2011)

For ground attack, visibility from the forward cockpit must be nice.


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## davparlr (Apr 29, 2011)

tomo pauk said:


> Dunno how well R-2800 would've fared at aft hull, cooling-wise.


 
The XP-56 had a buried 2800 and, while the aircraft had its problems, cooling did not appear to be one of them. Also, the B-36 and XB-35 both had buried air cooled radials and seemed not to have unsolvable problems with them.


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## Shortround6 (Apr 29, 2011)

tomo pauk said:


> Dunno how well R-2800 would've fared at aft hull, cooling-wise.



See: www.warbirdsresourcegroup.org - U.S.A.A.F. Resource Center - Northrop XP-56 "Black Bullet"

engine needed fan cooling, and an extension shaft, gear-box, revised exhaust ports and a few other changes. 



tomo pauk said:


> Allied planes could've picked some roll rate, with MGs relocated almost to centreline.



The twin boom design may have canceled some of that out. Most of the tail-less planes seemed to have handling problems.


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## tyrodtom (Apr 29, 2011)

Check out the Hungarian Marton XV-01 on the Axis History forum.
2 DB-605s in push-pull configeration. 
I think it's a fake, looks like someone did a photoshop job on Me-109 noses, and components of various other aircraft.


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## WJPearce (Apr 29, 2011)

Another push-pull that has not been mentioned is the Russian Moskalev SAM-13. Smaller than the Fokker but a very similar layout. SAM-13, Moskalev

All the WWII Rear-Engine fighters (built) I can think of have already been mentioned but right after the war there is the French Sud-Ouest SO 8000. Sud-Ouest SO 8000 Narval - shipboard fighter






And since the XB-35 and B-36 have been brought up, I'd like to add the Douglas XB-42. Douglas XB-42 Mixmaster





Of course, there are numerous WWII paper airplanes from all counties of both pusher and tandem designs and a few WWI pushers too. 

By edit: I forgot about the Bell Airacuda. It was an "Interceptor" but it would not be able to intercept much.
http://en.wikipedia.org/wiki/Bell_YFM-1_Airacuda





Sorry if I have strayed off-topic.


WJP


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## vikingBerserker (Apr 29, 2011)

The Soviets experimented with it as well, kinda looked like the SAAB actually. I'll have to dig up the name of it.

----------------------------
Oops didn't see it posted above


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## WJPearce (Apr 29, 2011)

Something deep in my little brain was still bugging me. Good news is I found what it was, another pusher. This one is from the Netherlands, the De Schelde S.21.
http://www.ww2aircraft.net/forum/aviation/de-schelde-s-21-a-8538.html


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## Grampa (Apr 29, 2011)

what about the biggest pusher-aircraft in service?

_View: https://www.youtube.com/watch?v=VGjyH2ulsCk_


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## tomo pauk (Apr 30, 2011)

P-39/63 would've made a cool US "Saab 21" after adding some booms empenage - just stumbled at the proposal @ the 'net 

added: A wind tunnel model, allegedly of such a machine, pic from Wikipedia:


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## WJPearce (Apr 30, 2011)

This falls into the "paper airplane" category but Bell had two pusher designs that got a "P" designation; P-52 and P-59 (not to be confused with the P-59A jet). 

The P-52 which was similar to the Saab 21 and Vultee XP-54, was to be powered with the Continental IV-1430. The aircraft was redesigned and re-powered with the R-2800. The redesign resulted in a new designation of P-59. I am fairly certain the wind tunnel model posted above is of the P-59 (which you are probably aware of).

To be sneaky, "P-59" was reused for the United States first jet, the P-59A (powered by England).

Now, if we want to go paper pusher airplanes and go big, hunt down the Curtiss XP-71. Below (hopefully) is an image of the XP-71 when it was to be powered by Wright R-2160 Tornados. Later on it was re-engined for R-4360s.






WJP


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## kration (May 1, 2011)

These are very 'paper plane' but show some examples of the British experimenting, including how to address the baling out issue:





















You can view them on the link here:

AeroScale :: WW2 British Secret Projects Vol. 1 by Peter Allen


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## tomo pauk (May 1, 2011)

From "Secret projects of tomo pauk", vol.394, the P-39 pusher. 
Additional pair of HMGs aside of wheels; perhaps additional fuel in booms to compensate for expanded ammo in front. Or maybe putting the HMGs into booms? Since the engine is turned front-to-back, air inlet is at hull side.


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## tomo pauk (May 1, 2011)

From the same book, Northrop pusher:


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## vikingBerserker (May 3, 2011)

I think Brewster had a proposed fighter with an engine in the back, I need to dig it out and see.


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## gjs238 (May 10, 2011)

It seems that for a ground attack aircraft a forward-placed cockpit may be advantageous.

For example, see Wikipedia page for the Henschel Hs 129, where it says "The aircraft was expected to be attacking its targets directly in low-level strafing runs, so the cockpit had to be located as close as possible to the nose in order to see the ground."
Henschel Hs 129 - Wikipedia, the free encyclopedia

A rear-engine pusher aircraft might be able to fullfull this requirement.


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## Shortround6 (May 10, 2011)

There were a number of proposals in various countries for such aircraft including this post war French aircraft.

http://www.avionslegendaires.net/Images/Gpotez75.jpg


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## Njaco (May 11, 2011)

ummm, one of the more famous "pusher" aircraft of WWII.


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## tyrodtom (May 11, 2011)

I know where the center of thrust is in the case of a prop aircraft.

Where is the center of thrust for a jet, or rocket ? At the Exhaust ?


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## dogsbody (May 12, 2011)

The Vickers Type 161.

Let Let Let ? Warplanes | Aviation Enthusiast Web Site

Vickers Type 161 - Wikipedia, the free encyclopedia


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## wuzak (Jun 9, 2011)

The McDonnell Model 1 was designed around the R-40C competition that gave us the XP-54, XP-55 and XP-56 (as well as the Bell XP-52/59). It had a fuselage mounted engine (P&W X-1800, Wright R-2160 or Allison V-3420) driving a pair of wing mounted pusher props via right angle drives and extension safts. It wasn't selected for further development, but got the USAAF interested enough to get McDonnell to design Model 2, which became the XP-67.


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## P-39 Expert (May 3, 2018)

Always thought that a single engined pusher was the ultimate WWII fighter. 
I would have used a radial like the P-56 with a cooling fan. These were already used in tanks powered by radial engines so they weren't new. Simplicity of the radial with the aerodynamics and reduced frontal area of an inline. Tricycle gear, heavy nose armament, pilot out front for better visibility, big fuel tank in fuselage over the CG. No propwash to fly through. Flying wing, canard or twin boom tail, it could have been done and would have been very efficient.


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## Shortround6 (May 3, 2018)

Tanks don't fly at 20,000ft. 

The mass airflow of a tank doesn't change much with speed and the mass airflow stays pretty constant as tanks don't often operated at high altitudes (number of tank battles in the Alps?) 

I would also note that even the radial tank engines used 80 octane fuel and used either very little or no supercharging so they were making much less power per cylinder. Which reduces the cooling load. 

Fan cooling could be done but tank engine installations were hardly a good pattern to follow.


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## wuzak (May 3, 2018)

P-39 Expert said:


> Always thought that a single engined pusher was the ultimate WWII fighter.
> I would have used a radial like the P-56 with a cooling fan. These were already used in tanks powered by radial engines so they weren't new. Simplicity of the radial with the aerodynamics and reduced frontal area of an inline. Tricycle gear, heavy nose armament, pilot out front for better visibility, big fuel tank in fuselage over the CG. No propwash to fly through. Flying wing, canard or twin boom tail, it could have been done and would have been very efficient.



The frontal area will not be reduced to that of a in-line powered fighter.

The XP-56 was a fat turd that was about 80-100mph slower than a similarly powered F4U, and 30-50mph slower than an F6F, itself no slim beauty.

Sticking a large diameter radial in the middle of an aircraft is probably not the cleverest thing to do....


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## wuzak (May 3, 2018)

Of the three XP projects that flew, the XP-55 was closest to its "guaranteed" performance, being around 30-40mph slower than estimated. It was, in fact, about the same speed as a similarly powered contemporary P-40. Climb rate was not as good, IIRC.

The XP-54 was the only one of the three to crack the 400mph barrier, albeit with special paint, filled gaps and hand polished finish. STill, that was 100mph slower than the original estimate, and some 70-80mph slower than later estimates.

It suffered from being bigger than a P-38, with less power from an experimental engine that was going nowhere, and was 2,500lb more than the P-38 for empty weight. Climb rate was found to be similar to a laden bomber....

The XP-54's weight nearly doubled from the original proposal. 

The XP-56's top speed was _estimated_ by NACA as 340mph after extrapolating test data.


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## P-39 Expert (May 4, 2018)

Shortround6 said:


> Tanks don't fly at 20,000ft.
> 
> The mass airflow of a tank doesn't change much with speed and the mass airflow stays pretty constant as tanks don't often operated at high altitudes (number of tank battles in the Alps?)
> 
> ...


Just an example showing that cooling fans were in use. The P-55 and P-56 used cooling fans.


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## P-39 Expert (May 4, 2018)

wuzak said:


> The frontal area will not be reduced to that of a in-line powered fighter.
> 
> The XP-56 was a fat turd that was about 80-100mph slower than a similarly powered F4U, and 30-50mph slower than an F6F, itself no slim beauty.
> 
> Sticking a large diameter radial in the middle of an aircraft is probably not the cleverest thing to do....


Depending on the inline fighter the frontal area could have been very close. 

My example uses a radial in the rear, not the middle.


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## wuzak (May 4, 2018)

P-39 Expert said:


> Depending on the inline fighter the frontal area could have been very close.
> 
> My example uses a radial in the rear, not the middle.




That, surely, would be even worse?


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## swampyankee (May 4, 2018)

Frontal area, _per se_, is not that important; wetted area and avoidance of separation are. Rear-engine pushers have a number of disadvantages, which have combined to keep it a rare configuration for prop aircraft.


If the prop is at the extreme rear, the possibility prop strikes on takeoff and landing has to be designed for. This means either longer landing gear or restrictions on rotation angle. The former increases weight, while the latter increases runway.
The engine is a big, heavy lump, the position of which dictates the location of the wing. This, in turn dictates the area of the tail surfaces.
Tailless aircraft, like the XP-56, run into the problem of limited pitch authority, which largely precludes flaps, and the elevators’ decambering the wing, which reduces lift at a given angle pf attack. These drive up runway requirements. Flying wings also tend to have poor pitch damping, which is one of the issues that killed the B-49. 
It’s nice to be able to see behind, but if the engine is behind the pilot, the largest fuselage section will be, too.


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## P-39 Expert (May 4, 2018)

wuzak said:


> That, surely, would be even worse?


Not really, eliminates the driveshaft and frees up the middle area for a large fuel tank.


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## wuzak (May 4, 2018)

P-39 Expert said:


> Not really, eliminates the driveshaft and frees up the middle area for a large fuel tank.



I was speaking aerodynamically.

Testing by NACA showed some loss of propeller efficiency when fitted to a big radial than for an inline, due to the greater blockage. 

I imagine that having a blockage directly in front of a prop would not be great for its efficiency.


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## wuzak (May 4, 2018)

swampyankee said:


> If the prop is at the extreme rear, the possibility prop strikes on takeoff and landing has to be designed for. This means either longer landing gear or restrictions on rotation angle. The former increases weight, while the latter increases runway.



The XP-54 did not have the prop at the extreme tail, but used the lower tails on the ends of the booms to prevent prop strikes, which obviously limited rotation.

Looking at the side view:







It seems possible that the Vultee deigners could have placed the main landing gear in the booms, near to or level with the prop, folding forward into the front of the boom/wing.

That would have eliminated the need for the lower fins and allowed for greater rotation.

And hopefully have reduced the very long take-off run.

The XP-55 didn't have any sort of protection from over-rotation and prop strike.






The placement of the wing precluded having the main gear any further back.

With its lower fin, the XP-56 didn't allow much rotation at all.


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## buffnut453 (May 4, 2018)

One of the last original designs by Brewster Aero Corp before it went under was for a twin-boom naval fighter:






Not sure how those booms would have stood up to arrestor landings, but it's an interesting concept.

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