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XyZspineZyX
10-05-2003, 01:09 AM
Puller's V Pusher's

Pusher's always seemed to look the more natural way to build aircraft, the engine/engines seem to me to look more at home facing backwards! I know that there are far more advantages having a/c with pullers a simple analogy is to imagine a 'Puller' as a car pulling a trailer - just point the nose where you want to go and everything behind just follows. Where as a 'Pusher' is the exact reverse - try reversing with a trailer, but in three dimensions.See, not so easy is it.
Still, it did not stop aircraft designers from trying to break from the norm. Here are a few I found, one I haven't put in is the B-36 though.I suppose you could say that the pusher's inherited the earth in the end though.

http://www.luft46.com/jhart/jh193-3.jpg

This design for a ground attack/dive bomber was similar to the BV P.192.01. The Jumo 213A engine drove a pusher propeller via a long shaft. A single fin and rudder was mounted beneath the fuselage to afford the rear propeller with protection during take off. The wing had a straight leading edge and tapered trailing edge. Projected armament was two MK 103 30mm cannon in the wings and two MG 151/20 20 mm cannon on the nose sides. 1000 kg (2200 lbs) of bombs could be carried.

http://www.luft46.com/bv/3bb208.jpg

The BV P.208.03 was the final design for a series of tailless aircraft designs by Blohm und Voß. A single Daimler Benz 12-cylinder DB 603L engine with a two-stage supercharger (2100 HP with MW 50 methanol-water injection) was imbedded within the fuselage aft of the cockpit. The engine drove a pusher propeller and was fed by an air intake located on the starboard side of the fuselage, with the radiator mounted beneath the fuselage. However, the piston engine was not an essential feature of this design but was only used when it became apparent that the original proposed turbojet would not be ready in time, so work was continued with the DB 603 engine substituted. The cantilevered wings were swept back at 30 degrees and were of a constant cross section. Downturned wingtips were connected aft of the main wing trailing edge by small booms, which served the purposes of elevators and rudders. The practicality of this control method was tested by Blohm und Voß by modifying the experimental Skoda-Kauba V-6 which was renamed and flown as the Skoda-Kauba SL-6. A tricycle undercarraige was used, with the wide-track main wheels retracting inwards into the center section and the nosewheel retracting forwards. All armament was in the aircraft's nose, and consisted of three MK 108 30mm cannon.

http://www.military.cz/usa/air/war/fighter/yfm/yfm1_infl.jpg

The YFM-1 Airacuda (sometimes spelled Aerocuda) was developed as a bomber destroyer aircraft. The FM in YFM stands for 'Fighter Multiplace' and is an USAAC designation, not to be confused with the USN designation (as used on the FM-2 Wildcat). It was an interesting design in that it had two engines, each with rearward-facing propellers, and forward-facing gunner's positions in the front of each of the extended engine nacelles. The 37mm cannon in each of these positions were remotely controlled by an operator seated in the fuselage behind the pilot, though a gunner was stationed behind each gun as a loader and for manual backup.
According to Major Alexander De Seversky's 1942 book "Victory Through Air Power", the Bell Airacuda "represents a great engineering achievment. But its designation as 'convoy fighter' is erroneous, since that requires different disposition of armament. With its maximum firepower directed forward, it really offers a preview of an effective long-range interceptor fighter."
It was decided to build an experimental series of 13 aircraft, first of which was completed in September 1939. It was a revolutionary design that unfortunately was plagued by mechanical problems and poor performance. As a result the program ended without the Airacuda entering mass production.

http://www.wpafb.af.mil/museum/research/p54s.jpg

Designed as a fast climbing interceptor, its planned role was changed to that of bomber destroyer. One unconventional feature was the emergency system which ejected the pilot and seat downward out of the aircraft below the propeller arc. The Army Air Corps ordered two test aircraft in January 1941. The first made 86 test flights in 1943; the second only flew once. Although Vultee hoped it would reach a top speed of 510 mph., its maximum was 381. Engine development problems hindered the program and design revisions increased weight and dramatically reduced expected performance, causing program cancellation.

http://www.wpafb.af.mil/museum/research/p55s.jpg

The XP-55 tested a "canard" feature in which the tail assembly was eliminated and the elevators were mounted in the nose. The vertical tail surfaces were placed on the wing tips. A handle in the cockpit allowed the pilot to jettison the propeller if bail out became necessary in an emergency. Three XP-55s were built and the first one made its initial flight on July 13, 1943. Performance was disappointing, stability problems persisted, and the program was canceled.


http://www.wpafb.af.mil/museum/research/p56s.jpg

The Northrop XP-56, was a tailless interceptor with a short fuselage mounted on a swept-back wing. It had two contrarotating propellers, each turning in the opposite direction. Other unusual features were its all magnesium, all welded airframe and the pilot's escape system. If he were forced to jump, he set off an explosive cord which blew away the propellers and the rear of the aircraft.
The first XP-56 made its maiden flight on September 6, 1943. It was destroyed later when a tire blew out. The second aircraft first flew on March 23, 1944, with a much larger dorsal vertical stabilizer to improve directional stability. The design still needed improvement and the program was canceled. By then the Army Air Forces was looking toward the introduction of jet propelled fighters.





<center>http://mysite.freeserve.com/Endodontics/sigs/WhirlySig03.jpg?0.8016962940949658

'Whirlwind Whiner'
The First of the Few

Message Edited on 10/05/0301:12AM by SECUDUS

XyZspineZyX
10-05-2003, 01:09 AM
Puller's V Pusher's

Pusher's always seemed to look the more natural way to build aircraft, the engine/engines seem to me to look more at home facing backwards! I know that there are far more advantages having a/c with pullers a simple analogy is to imagine a 'Puller' as a car pulling a trailer - just point the nose where you want to go and everything behind just follows. Where as a 'Pusher' is the exact reverse - try reversing with a trailer, but in three dimensions.See, not so easy is it.
Still, it did not stop aircraft designers from trying to break from the norm. Here are a few I found, one I haven't put in is the B-36 though.I suppose you could say that the pusher's inherited the earth in the end though.

http://www.luft46.com/jhart/jh193-3.jpg

This design for a ground attack/dive bomber was similar to the BV P.192.01. The Jumo 213A engine drove a pusher propeller via a long shaft. A single fin and rudder was mounted beneath the fuselage to afford the rear propeller with protection during take off. The wing had a straight leading edge and tapered trailing edge. Projected armament was two MK 103 30mm cannon in the wings and two MG 151/20 20 mm cannon on the nose sides. 1000 kg (2200 lbs) of bombs could be carried.

http://www.luft46.com/bv/3bb208.jpg

The BV P.208.03 was the final design for a series of tailless aircraft designs by Blohm und Voß. A single Daimler Benz 12-cylinder DB 603L engine with a two-stage supercharger (2100 HP with MW 50 methanol-water injection) was imbedded within the fuselage aft of the cockpit. The engine drove a pusher propeller and was fed by an air intake located on the starboard side of the fuselage, with the radiator mounted beneath the fuselage. However, the piston engine was not an essential feature of this design but was only used when it became apparent that the original proposed turbojet would not be ready in time, so work was continued with the DB 603 engine substituted. The cantilevered wings were swept back at 30 degrees and were of a constant cross section. Downturned wingtips were connected aft of the main wing trailing edge by small booms, which served the purposes of elevators and rudders. The practicality of this control method was tested by Blohm und Voß by modifying the experimental Skoda-Kauba V-6 which was renamed and flown as the Skoda-Kauba SL-6. A tricycle undercarraige was used, with the wide-track main wheels retracting inwards into the center section and the nosewheel retracting forwards. All armament was in the aircraft's nose, and consisted of three MK 108 30mm cannon.

http://www.military.cz/usa/air/war/fighter/yfm/yfm1_infl.jpg

The YFM-1 Airacuda (sometimes spelled Aerocuda) was developed as a bomber destroyer aircraft. The FM in YFM stands for 'Fighter Multiplace' and is an USAAC designation, not to be confused with the USN designation (as used on the FM-2 Wildcat). It was an interesting design in that it had two engines, each with rearward-facing propellers, and forward-facing gunner's positions in the front of each of the extended engine nacelles. The 37mm cannon in each of these positions were remotely controlled by an operator seated in the fuselage behind the pilot, though a gunner was stationed behind each gun as a loader and for manual backup.
According to Major Alexander De Seversky's 1942 book "Victory Through Air Power", the Bell Airacuda "represents a great engineering achievment. But its designation as 'convoy fighter' is erroneous, since that requires different disposition of armament. With its maximum firepower directed forward, it really offers a preview of an effective long-range interceptor fighter."
It was decided to build an experimental series of 13 aircraft, first of which was completed in September 1939. It was a revolutionary design that unfortunately was plagued by mechanical problems and poor performance. As a result the program ended without the Airacuda entering mass production.

http://www.wpafb.af.mil/museum/research/p54s.jpg

Designed as a fast climbing interceptor, its planned role was changed to that of bomber destroyer. One unconventional feature was the emergency system which ejected the pilot and seat downward out of the aircraft below the propeller arc. The Army Air Corps ordered two test aircraft in January 1941. The first made 86 test flights in 1943; the second only flew once. Although Vultee hoped it would reach a top speed of 510 mph., its maximum was 381. Engine development problems hindered the program and design revisions increased weight and dramatically reduced expected performance, causing program cancellation.

http://www.wpafb.af.mil/museum/research/p55s.jpg

The XP-55 tested a "canard" feature in which the tail assembly was eliminated and the elevators were mounted in the nose. The vertical tail surfaces were placed on the wing tips. A handle in the cockpit allowed the pilot to jettison the propeller if bail out became necessary in an emergency. Three XP-55s were built and the first one made its initial flight on July 13, 1943. Performance was disappointing, stability problems persisted, and the program was canceled.


http://www.wpafb.af.mil/museum/research/p56s.jpg

The Northrop XP-56, was a tailless interceptor with a short fuselage mounted on a swept-back wing. It had two contrarotating propellers, each turning in the opposite direction. Other unusual features were its all magnesium, all welded airframe and the pilot's escape system. If he were forced to jump, he set off an explosive cord which blew away the propellers and the rear of the aircraft.
The first XP-56 made its maiden flight on September 6, 1943. It was destroyed later when a tire blew out. The second aircraft first flew on March 23, 1944, with a much larger dorsal vertical stabilizer to improve directional stability. The design still needed improvement and the program was canceled. By then the Army Air Forces was looking toward the introduction of jet propelled fighters.





<center>http://mysite.freeserve.com/Endodontics/sigs/WhirlySig03.jpg?0.8016962940949658

'Whirlwind Whiner'
The First of the Few

Message Edited on 10/05/0301:12AM by SECUDUS

XyZspineZyX
10-05-2003, 01:28 AM
The problem with pusher aircraft is simple. First it causes things to be placed differently internally to get the CG right.

Then there's the problem rotating for takeoff without striking the prop on the runway.

The bonus is it gives a better view to the pilot, and he can be right in the nose of the aircraft. It's also more aerodynamic. Although it suffers cooling problems.
Also the aircraft needs more takeoff room, and in a stall or right before a stall you lose all control.

It exposes the prop, and the engine to enemy fire from the rear.

Every take-off is optional, but every landing is mandatory!

XyZspineZyX
10-05-2003, 03:23 AM
I've heard that the biggest reason for pushers not gaining a lot of popularity is because the air feeding the prop is "unclean" after flowing over the fusalage, and isn't as efficient as a puller prop which gets clean air before the aircraft passes through it.

Otherwise it allows for a lot of design freedom.