Luftwaffe XP-75?????

[Bill G.]

My mind got to wandering yesterday with a crazy idea. So here it goes.

Most of us have heard of the XP-75 Fisher Eagle. It was an interesting idea even though it didn't work. This is the basis for my idea.

What if the Luftwaffe had had even more problems getting their jet engines to work. They heard of the XP-75 and thought what the heck. Why not try our own version.

Single piston engine fighters were going nearly as fast as they were going to go without exotic engines. So you are going to need two engines to go faster. The P-38 was about the best twin engined fighter. So that would be a good starting point.

The P-38 had a big problem, compressibility. So take the swept wings of an Me-262 to delay compressibility. Add the tail and horizontal stabilizers of the 262 to the tail booms. To reduce drag and turbulent air flow around the tail, remove the radiators from the tail booms and replace them with the radiator from the P-51 Mustang.

For engines, take the best from the Bf-109G. Delete the guns as these will, like the P-38, be in the nose. And like the P-38, the props will contra-rotate.

I would like to hear your views as to how this hybred would work.

And if anyone is so bored and has the stuff to "draw this", I would like to see what this might look like.

Anyways, thanks for reading!

Bill G.

 

[davebender]

2 easy ways for the Luftwaffe to make a faster piston engine fighter aircraft.
- The historical Do-335.
- A modified Fw-190 D9 powered by the 2,500 hp Jumo 222 engine.

 

[Colin1]

It could have looked like one of these (bar no #4, which actually became the P-38 ).
I think no #6's engine arrangement was interesting, the Germans clearly thought so with the Do335 and those booms, freed from carrying engines, had the potential for large calibre weapons.

No #1 is almost a Mosquito.

Sketches of six designs roughed out by Kelly Johnson for the 1937 Air Corps Fighter competition. Number four was selected. (Lockheed California Company)

 

[GrauGeist]

#5 looks almost like the Bf109Z/Me609

 

[davebender]

That aircraft offers interesting possibilities. The pilot sat in the port cockpit. The starboard cockpit was faired over. You could use this aircraft as a high performance night fighter with the radar operator in the starboard cockpit.

Me-109 Z-3
Messerschmitt Me 109Z Luft '46 entry
2 x Jumo 213E engines. Should be capable of about 475 mph.
4 x Mk 108 3cm cannons.
1 cannon firing through each prop shaft. 2 cannons in the center wing section.

 

[GrauGeist]

As far as a swept-wing jet style prop job, there are a few that I am aware of, one of which being the Messerschmitt Me334.

While the Germans were developing the Me163 Komet, a temporary engine shortage caused Lippisch to conceive of a propeller equivalent by altering the Komet's tail and configuring the fuselage to accept a DB605 pusher.

The specs are:
Me334 (pic 1)
Length : 7.00m (22' 11")
Wing Span : 9.30m (30' 6")
Engine : DB605A-C V-12 X 1
Max Speed : 700Kmh (435Mph)
Crew : 1
Armament : MG151/20 20mm X 2

On the American's side, you had the Vultee XP-54, Curtiss XP-55 and the Northrop XP-56. The XP-56 looks remarkably like the Me334 with it's swept wings. All were attempts at increasing speed by "pushing". The XP-54's engine was based on "Hyper" technology, where they were trying to achieve 1Hp per Square inch displacement. Interesting stuff.

Specs are:
XP-54 (pic 2)
Length: 16.69m (54' 9")
Wingspan: 16.41m (53' 10")
Engine: Lycoming XH-2470-1 X 1
Max Speed: 613Kmh (381Mph)
Crew: 1
Armament: 37mm cannon X 2, .50 cal (12.7 mm) MG X 2


XP-55 (pic 3)
Length: 9m (29' 7")
Wingspan: 12.4m (40' 7")
Engine: Allison V-1710-95 V-12 X 1
Max Speed: 628Kmh (390Mph)
Crew: 1
Armament: .50 cal (12.7 mm) MG X 4


XP-56 (pic 4)
Length: 8.38m (27' 6")
Wingspan: 12.96m (42' 6")
Engine: P&W R-2800-29 radial X 1
Max Speed: 749Kmh (465Mph)
Crew: 1
Armament: 20mm cannons X 2, .50 cal (12.7 mm) MG X 4

 

[tomo pauk]

The 109Z was the way.

Since the basic 109 was dirt cheap, developing the twin version would lead to abandonment of Bf-110-210-410 line with an aircraft of the superior performance. It also had the potential for being fast potent bomber killer and night fighter.

My another favourite is a Me-262 hull aerodinamic surfaces with prop engines; perhaps with the DB-603 we've just saved from 210-410 series Four 30mm cannons flying at 500mph anyone?

 

[Colin1]

My another favourite is a Me-262 with prop engines; perhaps with the DB-603 we've just saved from 210-410 series Four 30mm cannons flying at 500mph anyone?

As opposed to an Me262 with jet engines?
Four 30mm cannons flying at 540mph

 

[tomo pauk]

My cannons would be flying in numbers in 1943...

 

[GrauGeist]

the 'Z would have been a good climber and fast in level flight, but it's handling in a fight would have been much like the Me410...the Doppelganger they made in the "Z" and the Me605 were heavy...enough to collapse the landing gear during trials...

And speaking of heavy, you do realize the Me262's airframe was heavy...so you would have to find a piston engine (radial or V) that can put out power that equalled or exceeded the 004...

 

[Colin1]

And speaking of heavy, you do realize the Me262's airframe was heavy...

double post???

 

[Colin1]

And speaking of heavy, you do realize the Me262's airframe was heavy...

I make it roughly 8,000lbs (empty weight) minus the Jumos at about 1,600lbs each, give or take
then add the weight of 2 x DB603s

I'm not seeing 500mph

 

[tomo pauk]

the 'Z would have been a good climber and fast in level flight, but it's handling in a fight would have been much like the Me410...the Doppelganger they made in the "Z" and the Me605 were heavy...enough to collapse the landing gear during trials...

The good climbe and a high speed make a true boom-and-zoom fighter, making the Zwilling a good (excellent?) choice. As for the troubles for landing gear...methinks that German engineers would've solve that issue.

And speaking of heavy, you do realize the Me262's airframe was heavy...so you would have to find a piston engine (radial or V) that can put out power that equalled or exceeded the 004...

Any numbes that would back the statement that Me-262's airframe was heavy?
And since when the 004 was considered as a world beater when it comes down to thrust?

 

[GrauGeist]

I make it roughly 15,000lbs minus the Jumos, give or take
then add the weight of 2 x DB603s

DB603 = 920 kg (2,030 lb) - each
DB605 = 730 kg (1,642 lb) - each
Jumo213 = 940 kg (2,072 lb) - each

And just for the heck of it, let's toss in a powerful radial;

BMW801 = 1,055 kg (2,325 lb) - each

compared to the actual engines:
BMW003 = 562 kg (1,240 lb) - each
Jumo004 = 719 kg (1,585 lb) - each

I'm not seeing 500mph

You and me both, not by a long-shot!

 

[tomo pauk]

I make it roughly 8,000lbs (empty weight) minus the Jumos at about 1,600lbs each, give or take
then add the weight of 2 x DB603s

I'm not seeing 500mph

You and me both, not by a long-shot!

The Twin Mustang weighted 16,000lb empty, while my prop Schwalbe sould be around 12000lb empty*. The Twin had 3m greater wing span too, with Schwalbe having swept wings to benefit further.
If the Twin Mustang could do 460mph+ with 3000HP, then the prop Schwalbe with 3500HP would be faster, nest'ce pas?


*empty weight of of the Me-262 was almost 10,000lb

 

[GrauGeist]

F82 (twin Mustang):
Empty weight: 15,997lbs (7,271kg)
Max speed: 460Mph (740Kmh)

Bf109Z (based on joined Bf109F):
Empty weight: 13,224lbs (6,000kg)
Max speed: 462Mph (743Kmh)

Me609 (based on joined Me309):
Empty weight: 11,660lbs (5,247kg)
Max speed: 472Mph (760Kmh)

Compared to Me262A1/a (original configuration with Jumo004 X 2):
Empty weight: 9,709lb (4,404kg)
Max speed: 559Mph (900Kmh)

Now, we remove the two Jumo 004B engines: 1,585lb (719kg) x 2 = 3,170lb (1,438kg)
Me262A1/a without engines = 6,539lbs (2,966kg)

So let's take 2 DB603 V-12 engines, and install them into the empty Me262:
DB603 @ 2,030lbs (920kg) X 2 = 4,060lbs (1,840kg)
Result is a weight of 10,599lbs (4,806kg)

That's a weight increase of 890lbs (402kg) with a reduction of roughly 100Mph (160Kph) in speed...

And what happens if you put ammunition and fuel in the machine?

The good climbe and a high speed make a true boom-and-zoom fighter, making the Zwilling a good (excellent?) choice. As for the troubles for landing gear...methinks that German engineers would've solve that issue.

As far as "Boom and Zoom" tactics go, it works as long as the enemy can't keep up with you...The allies had aircraft that could both "Boom and Zoom" and "Turn and Burn"...

The Germans dropped the Doppelganger projects in favor of the Ta152, because it of thier development problems and the fact that they just weren't performing as well as they had hoped.

 

[Colin1]

Now, we remove the two Jumo 004B engines: 1,585lb (719kg) x 2 = 3,170lb (1,438kg)
Me262A1/a without engines = 6,539lbs (2,966kg)

So let's take 2 DB603 V-12 engines, and install them into the empty Me262:
DB603 @ 2,030lbs (920kg) X 2 = 4,060lbs (1,840kg)
Result is a weight of 10,599lbs (4,806kg)

That's a weight increase of 890lbs (402kg) with a reduction of roughly 100Mph (160Kph) in speed...

And what happens if you put ammunition and fuel in the machine?

I don't think it adds up to 500mph
saddled with props, it won't be alot cleaner than a P-82 airframe, if at all, given that it now has three nacelle frontal cross-sectional areas to the P-82's two.

I'd be surprised if it was faster than a P-82 or de Havilland Hornet and that was some margin away from 500mph too.

It sounds like you'd be running at the bomber streams in a jet wannabee that can't run as fast as a jet and can't dogfight that well once it's caught.

 

[davebender]

Since the basic 109 was dirt cheap, developing the twin version would lead to abandonment of Bf-110-210-410 line with an aircraft of the superior performance. It also had the potential for being fast potent bomber killer and night fighter.

The Me-109Z is a fighter aircraft. The Me-410 is a light bomber with a 1,000kg bomb bay. Not the same thing. In any case Me-410 production ended during 1944.

 

[GrauGeist]

Yeah, I was rounding out in favor of Tomo, using the least amount of installed weight for the most amount of performance gained...and I ended up with something that *might* give me 460Mph.

When I was comparing the piston engines versus the jet, I didn't add projected weight for such things as increased cowling, coolant and additional oil. Also would need to add weight for the props, gearing, exhaust manifolds, etc...

The weight stated for the jet engines is total weight (ready to install) versus the long-block weight (no prop, manifold, final drive/gearing) of the piston engines.

I mean, don't get me wrong, it would be an interesting sight to see, a prop-driven Me262...but other than an oddity, I think it would be a one-way trip to drive it into battle...

 

[delcyros]

If You want high altitude speed, then You better go with the Ar-240. Install two Db-603 each and GM-1 augmentation. This was good for 466 mp/h top speed in the clean recon version, less in the destroyer version.
If You want even more high altitude performance install a db-605T slave engine in the bomb bay to drive the superchargers of the main engines. Critical altitude should be ~12.000m and exhoust thrust at this altitude is higher than with Jumo-004. You should be able to hit crit Mach at very high altitude, or around 500 mph.