# Assessing the Dornier 335’s capabilities as a fighter



## Soren (Dec 27, 2009)

Assessing the Dornier 335’s capabilities as a fighter.







Fighter, A-1 A-5.

*Specifications:*

Loaded Weight: 9590 kg

Wing area: 38.5 m^2

Wing span: 13.8 m

Wing aspect ratio: 4.94

Wing Clmax: ~ 1.65 (?)

Length: 13.87 m

Powerplants: 2x DB-603E engines rated at 1,800 PS take off power, and 2,400 PS at emergency power using methanol water injection. 

Top speed: 763 km/h @ 6,400m (565 km/h on 1 engine)

Climb rate: 23.3 m/s (4,600 ft/min)

Service Ceiling: 11,800 m

Armament: 3x 30mm Mk103 automatic cannons + 2x 20mm MG151/20 automatic cannons

Optional armament: 2x or 4x R4M rocket ramps with 12 rockets each (total of 48 rockets), 1x 500 kg bomb in internal bombay (removal of belly fuel tank) 

Ammunition types:
HE(M), HE(I), AP(T), AP(I).

*Other Equipment:*

EZ-42, computing gunsight

Kommandogerät, engine propeller management computer 

Patin PKS 12b, course steering Autopilot

Ejection seat

Electric heating of wing leading edges for de-icing.

Heated windscreen

Layout:


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## davebender (Dec 28, 2009)

Clearly it's superior to every other piston engine fighter if flown with the proper Boom Zoom tactics. In fact it might be faster then early model Gloster Meteor jet fighter aircraft.

I wonder about production cost. Do we have any data concerning man hours to build the airframe?


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## Soren (Dec 28, 2009)

It was certainly faster than any Meteor in service during the war. But the Ta-152H was just as fast and did climb faster, plus it featured better maneuverability and a much higher ceiling. But the Do-335 was a more versatile a/c.

As for cost, well I'm thinking it was probably in the vicinity of the same as a Ju-88G.


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## davebender (Dec 28, 2009)

Light fighter vs heavy fighter. High-low mix. Whatever you want to call it.

The Ta-152H becomes the mass production light fighter. It takes over from the Me-109 series, which is due for retirement after a decade of stellar service.

The Do-335 has serious firepower (3 x Mk103 cannon) plus a combat radius of about 700 miles with drop tanks. It also has space for a radar operator. It specializes in killing heavy bombers both at night and during the daytime.


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## MikeGazdik (Dec 28, 2009)

Awesome plane. It certainly would have caused B-17's and B-24's serious trouble. I think though they would have trouble dealing with the Mustang escort. At least, the P-51's would not make it easy.


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## timshatz (Dec 28, 2009)

MikeGazdik said:


> Awesome plane. It certainly would have caused B-17's and B-24's serious trouble. I think though they would have trouble dealing with the Mustang escort. At least, the P-51's would not make it easy.



I kinda wonder if they would've sent it after the American Bombers. It has the speed and the firepower. But there were swarms of escort fighters out there waiting for anything to come up. While it had them on the speed and was probably fairly manuverable, it would've been chased by everything up there. Would they've sent it? Yes. Would it knock down bombers? Yes. Would it have survived? Probably not. Odds were just too long. 

It would've made a great intruder. Even a daylight intruder. Do what the Mosquito did but in reverse. Go over England and stirr up trouble. While the RAF would've been after it, the very nature of the mission would've made and intercept difficult. Whereas the bombers were an obvious target, the Do would've had the whole island to chose to attack. Can't cover everything. 

High Altitude Photo Recon, very good platform. 

Ground attack? Maybe, but seems like a waste. Use the Armored up 190s for that.


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## riacrato (Dec 28, 2009)

I would agree. EK 335s assessment of it in the heavy fighter role wasn't too promising. Granted the version they flew had a castrated performance, I still think they were essentially with what they said: The plane will likely perform in the early '45 air battles like the Me 410 did a year earlier: good when there's no escorts, but will get into serious trouble if intercepted.

As an intruder/nightfighter it'd be great though.


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## FLYBOYJ (Dec 28, 2009)

It would have been a great "boom and zoom" fighter - plenty of room for growth into other roles. Push-pull aircraft in general are notorious for over heating problems in the aft engine, especially while on the ground, I wonder if the 335 had any such problems?


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## davparlr (Dec 28, 2009)

This is a rehash of previous discussions but since we are talking about proposed aircraft, my feelings are that Germany should have spent it development efforts on the clearly superior Me-262 and maybe other jets instead of aircraft like the Ta-152, and especially the Do-335, that were not going to provide significant advantages over the latest Allied aircraft such as the P-51H, P-51M, F4U-4, and the latest Spitfire marks.

Here’s a comparison of the Do-335A1/5 to the XP-72, an allied aircraft whose very successful flight test program was cancelled because the Allies were moving on in technology. If we assume that the war had continued and jets were not becoming operational, and these two aircraft, whose development was parallel, met in the skies over Europe in the summer of ’45, this is how they might match up.


Empty Weight-lbs
P-72 11476 
Do 16280

Loaded Weight-lbs
P-72 14433	
Do 21142

Length-ft	 
P-72 36.6
Dop 45.6

Wingspan-ft
P-72 40.9
Do 45.3

Wing Area- ft^2 
P-72 300
Do 414.4

Wing Loading- lb/ ft^2
P-72 *48.1* 
Do 51

Power–Hp(PS)
P-72 3450
Do 4800

P/W Loaded- hp/lb 
P-72 *.24* 
Do .23

Max Airspeed-mph
P-72 *480 (tested, without turbo) to 490+ (est.)*
Do 474

Climb Rate-ft/min 
P-72 *5280*
Do 4600

Ceiling-ft
P-72 *42,000*
Do 38,000 


I think it is apparent that the Do-335 would be at a disadvantage as it is exceeded my most all performance criteria.


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## DerAdlerIstGelandet (Dec 28, 2009)

I have read that the Pheil did have problems during development with the rear engine overheating. As you stated though, it is common with these types of aircraft.


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## red admiral (Dec 28, 2009)

> It was certainly faster than any Meteor in service during the war.



Faster than the eight prototypes and twenty Meteor Mk.Is. Now, changing over to the Meteor Mk. III in December 1944 and gave a significant speed advantage at all heights, the Do 335 only coming close at full throttle height.



> I have read that the Pheil did have problems during development with the rear engine overheating.



Stability problems at high speed as well.

"One of the problems that had manifested itself as test-flying progressed was that it was found that the automatic opening of the rearoil cooler flaps caused an uncontrolled spontaneous flick which was transmitted through the lateral axis, causing the aircraft to porpoise. In order to establish the reason for this, and surmount any overheating problems with the rear engine, several tests were undertaken with the V6 fuselage "

In spite of its remarkable performance, the Do 335 failed to be seen in any numbers in Luftwaffe service. There were three main reasons for this. Firstly, the bombing of the Dornier factories which caused severe disruption to production plans; secondly the problem of the weakness of the undercarriage which was never satisfactorily solved; and thirdly, difficulties with stability. An insight into this last problem was given in a preliminary interrogation by USAAF staff of the respected Luftwaffe fighter ace, Generalleutnant Adolf Galland, on 14 May 1945:

"Galland had flown the Do 335, but although he found it a good aircraft, he believed it would require considerable improvement in design before it could be accepted as operational. As a twin engined fighter it lacked the stability required, and usually found, in such aircraft. He attributed this lack of stability to the distance between the two engines. In comparison to a single-engined fighter he stated that it handled 'too heavy'."

Dornier Do 335: The Luftwaffe's Fastest Piston-Engine Fighter by J. Richard Smith , Eddie J. Creek and Gerhard Roletschek


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## drgondog (Dec 28, 2009)

If Mustangs and Tempests could successfully chase down a fighter that was 100mph faster (Me 262) why does anyone think that the Do335 would be a formidable threat to USAAF bomber fleets in 1945 - Given the coverage both for escort and sweeps? 

Boom and Zoom has questionable sufficient advantage in performance to remain quasi invulnerable. There was always a high escort ~ 5000 feet above the bomners for at least one squadron over just about every wing at that stage of the war. 335 could definitely dive past to make initial attack but not sure of staying away from escorts even if after the initial attack.

It certainly would/should have been more effective than Fw 190 and me 109 but at what cost to the Me 262 deliveries?


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## Bug_racer (Dec 28, 2009)

how about adding some rocket pods for quick getaway acceleration ?


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## DerAdlerIstGelandet (Dec 28, 2009)

drgondog said:


> If Mustangs and Tempests could successfully chase down a fighter that was 100mph faster (Me 262) why does anyone think that the Do335 would be a formidable threat to USAAF bomber fleets in 1945 - Given the coverage both for escort and sweeps?



I have been contemplating the same thing. While I think it was a remarkable aircraft, I find it hard to believe it would have given the Luftwaffe any advantage at all.


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## parsifal (Dec 28, 2009)

It has the disadvantage also of simply using two engines, instead of one, which adds to the production costs enormously.

In order for there to be no impact on serviceability rates and logistics, the Germans would need to phase out one of their other types. Since the retention of the Ta 152 and the retention of the Me 262 have already been mentioned, we also have the He 162 to consider, and a couple of other types as well, all doing basically the same job, all using different parts, fuels, ammunition, lubricants, etc etc. Luftwaffe serviceability rates would have suffered if yet another type were added to the inventory.


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## davebender (Dec 28, 2009)

Once the Me-262 enters mass production it would be senseless to mass produce the Do-335 also. It you want the Do-335 in mass production then you must assume either:
a. The Me-262 program was a failure.
b. The Do-335 program begins early. Perhaps during 1937 concurrent with the Fw-190 program.


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## FLYBOYJ (Dec 28, 2009)

davebender said:


> Once the Me-262 enters mass production it would be senseless to mass produce the Do-335 also. It you want the Do-335 in mass production then you must assume either:
> a. The Me-262 program was a failure.
> b. The Do-335 program begins early. Perhaps during 1937 concurrent with the Fw-190 program.



How about dumping the Bf 109 and Me 110?????


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## Shortround6 (Dec 28, 2009)

davebender said:


> Once the Me-262 enters mass production it would be senseless to mass produce the Do-335 also. It you want the Do-335 in mass production then you must assume either:
> a. The Me-262 program was a failure.
> b. The Do-335 program begins early. Perhaps during 1937 concurrent with the Fw-190 program.



There is little or no sense to an early Do-335 program as the armament available to the Luftwaffe doesn't make much sense for a tandem engine single seat fighter. The through the engine mount for the 20mm MG/FF didn't work all that well and even if they thought it would, that leaves you with a twin engine fighter armed with a single cannon and that gun with rather limited ammo capacity. Yes you can put guns in the wing but at the time the 20mm/FF used a 60 round drum. Using two engines to haul the same armamet as the 109E-3 was supposed to carry doesn't seem to good. Unless of course you put a couple of MG 17s in the wing roots in addiotion to putting them in cowl.
The Bf 110 carried 3 drums per cannon but used the radio operator/rear gunner as the drum changer. Maybe not real practical but no worse than the first Beaufighters and certainly better than being limited to a single drum per gun as a wing installation or engine installation would require. 
Any guns besides the MG 17 and the MG/FF don't show up in numbers until 1941/42.


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## MikeGazdik (Dec 29, 2009)

I know little about the 335, but looking at it I would assume the props counter-rotate. That being, there would have to be some tremendous torsional loads mid fuselage. That would have to cause serious problems in certain maneuvers. I would also think because of those loads the middle of the fuselage would be very intolerant of battle damage.

As a technology though, I think the engineering is just incredible!


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## Soren (Dec 29, 2009)

Regarding Galland and his comments on the Do-335. Well first of all I'm not even sure he ever flew one, secondly if he did it must have been an early prototype cause according to Do-335 chief test pilot Hans Werner Lerche the Do-335 featured very light controls and the handling characteristics of the a/c were non other than excellent, the a/c featuring a fast roll rate and impressive turn performance. Furthermore Lerche says the a/c was very stable in flight, so again not sure where red admiral gets his info from, but the A-0 atleast didn't feature any of the weaknesses he claims.


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## Soren (Dec 29, 2009)

davparlr said:


> This is a rehash of previous discussions but since we are talking about proposed aircraft, my feelings are that Germany should have spent it development efforts on the clearly superior Me-262 and maybe other jets instead of aircraft like the Ta-152, and especially the Do-335, that were not going to provide significant advantages over the latest Allied aircraft such as the P-51H, P-51M, F4U-4, and the latest Spitfire marks.
> 
> Here’s a comparison of the Do-335A1/5 to the XP-72, an allied aircraft whose very successful flight test program was cancelled because the Allies were moving on in technology. If we assume that the war had continued and jets were not becoming operational, and these two aircraft, whose development was parallel, met in the skies over Europe in the summer of ’45, this is how they might match up.
> 
> ...



Davparlr,

Lets remember that this is the performance of the Do-335A-0 in 1944, by mid 45 it was to powered by two even more powerful high altitude DB603 engines providing 2,700 hp each, plus a GM-1 system which would've increased the ceiling by atleast 10,000 ft. So by mid 45 when the P-72 would've entered service in europe the Do-335 would be hitting speeds of 500 mph and climb at 5,500 ft/min. So the Do-335 P-72 would've been very close.

Also regarding the wing loading, the Do-335 has a much higher Clmax no doubt, the wing being very thick and the airfoil being used optimized for great lifting capability. The P-72's wing was optimized more for all out speed.


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## Soren (Dec 29, 2009)

drgondog said:


> If Mustangs and Tempests could successfully chase down a fighter that was 100mph faster (Me 262) why does anyone think that the Do335 would be a formidable threat to USAAF bomber fleets in 1945 - Given the coverage both for escort and sweeps?
> 
> Boom and Zoom has questionable sufficient advantage in performance to remain quasi invulnerable. There was always a high escort ~ 5000 feet above the bomners for at least one squadron over just about every wing at that stage of the war. 335 could definitely dive past to make initial attack but not sure of staying away from escorts even if after the initial attack.
> 
> It certainly would/should have been more effective than Fw 190 and me 109 but at what cost to the Me 262 deliveries?



I agree Bill. Concentrating on Me-262 development production would've been better. 

The Do-335 was pushing the envelope for piston engined fighter development to its very limits, the jet age was on its way.


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## tomo pauk (Dec 29, 2009)

Agree with Bill Dave (amongst others), the right time for heavy, piston-engined (day) fighter was the 1st half of war. The plain-vanilla DB-601/605 design, weighting like Bf-110/P-38, with as much armament fuel it could've carried. 
Every design aimed for 1944 and later needs jet engines to be worth bothering about.

The night fighter version is much more viable IMO.


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## riacrato (Dec 29, 2009)

The Do 335 was designed according to a requirement asking for a high-speed bomber / intruder / recon. In that role I think it could've been successful even in late '45, the only active design surpassing it in terms of speed being the Ar 234. But you have to ask yourself if those jet engines wouldn't have done a better job on top of He 162s, so the niche is still there for the Do.


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## davebender (Dec 29, 2009)

Without the 30,000+ Me-109 light fighters the German air war would be lost during September 1939.

The 1936 to 1937 RLM competition for a complementary long range fighter is a different story. I'm all for an open competition. Note that at this early date we are thinking in terms of a single seat day fighter only. There is no radar operator and his associated equipment.

*1937 RLM Heavy Fighter Competition* (my version).
- All aircraft will be powered by DB600/DB601/DB605 engines. Thus we have a level playing field.
- Must be faster then an Me-109 when powered by the same engine version. A heavy fighter cannot dog fight a light fighter so high speed becomes the primary advantage.
- Like all Boom Zoom aircraft, this heavy fighter must have enough firepower to kill on a single brief diving pass.
- Like all Boom Zoom aircraft, climb and dive speed should be good. 
- Like all Boom Zoom aircraft, handling characteristics must be good at high speed.
- No rear firing weapons for self defense. This is a fighter, not a light bomber.
- Combat radius of 500 miles with internal fuel. Enough to accompany typical medium bomber missions.
- External hard points for drop tanks or bombs. This provides additional mission flexibility.
- As with all German aircraft programs, production cost matters. 
- Foreign aircraft companies are welcome to compete. I doubt Lockheed or North American can get a prototype P-38 or P-51 ready in time. But the door is open if they are up to the job.
- 1937 Germany does not have a large enough economy or military-industrial complex to produce more then one model of long range fighter. So the winner gets the entire contract.
- Initial production will be about 50 aircraft per month. This relatively expensive aircraft is a bomber escort, not a replacement for the dirt cheap Me-109 as a general purpose fighter aircraft.

You be the judge. Who wins the 1937 RLM heavy fighter competition?


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## Shortround6 (Dec 29, 2009)

Who wins?

Messerschmitt's 110 is as likely as any if you don't come up with different guns than the Germans had at the time. An escort fighter that runs out of ammo after after 8 seconds of firing time doesn't do you much good even if it has gas for 500 miles of radius. even switching to a 100 round drum only gets you 12-13 seconds firing time. Unless you fall back on the secondary MG installation like the Germans did but that does limit the effectiveness of the airplane. 

trying to carry triple the amount of fuel per engine isn't going to do much for speed or climb vrs the single engine fighter either. Trying to use tricycle landing gear like a Do-335 is going to be heavier than a tail dragger design. 
Then there is the radio question. While the Germans could make better radios than the British, a radio that will work at 500 miles will be a bit different than one that works at 150 miles. will it need a dedicated operator?

I have read that the radios in the 109 were single channel, pre-set before take off. It made cooperation difficult between different formations and ground control. British radios had 4 pre-sets. 
What were the capabilities of the 110 radios?

If you need a rear seater to handle the radio and load the guns do you give him a rear MG or not?

Field length must also be considered. Boom and zoom is great but if your wing loading is so high that your take-off/landing speed keeps you from using a number of airfields (or keeps you grounded in certain weather conditions) what have you really gained in flexability?


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## davebender (Dec 29, 2009)

In my opinion the Fw-187 was superior to the Me-110 in every way. The smaller Fw-187 is probably less expensive as well. So why would the Me-110 win?

An early model tandem engine Dornier fighter is the wild card. How does a Do-334 1/2 compare with the Fw-187? Remember they have identical engines. The Dornier fighter is lighter then the historical Do-335 (no weapons bay, no 2nd crew member, lighter engine mounts for the smaller engines etc.). Can Dornier even put together a practical fighter at this early date? They do have several decades experience with tandem engine seaplanes, most of which had excellent reputations.


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## timshatz (Dec 29, 2009)

With the Ta152 and Me262 coming online, the Do335 becomes less of a viable call as a fighter/interceptor. I imagine both of them were easier to build, less expensive and produced comparable, if not superior, performance. With those two coming online (the 152 and 262), stop production of the 109 and turn the 190 into a fighterbomber in the mold of the P47/Typhoon.

That being said, the Do becomes a better call when it comes down to recon, intruder and long range work. Figuring it could carry a very good fuel load in drop tanks, it could be used for maritime recon/intruder with an extra seat behind the pilot similar to that of the night fighter option. It has all the characteristics of being a very versitile platform. 

As someone else noted, if it were available earlier, in leu of the the 110, it would've given the Luftwaffe a very useful bird to use in the Bay of Biscay and far out into the North Atlantic. Would definitely been able to handle any of the Allied types it would've ran into (Beaufighters, B24s, ect) and still carried enough armament to be a threat to shipping (allied hunter/killer groups, convoys, MTB, whatever it could get it's nose on) in and around the British Isles. 

Kind of like the RAF anti-shipping strikes in reverse.


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## Soren (Dec 29, 2009)

Good post timshatz, I agree.


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## timshatz (Dec 29, 2009)

Thanks Pal.


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## davparlr (Dec 29, 2009)

Soren said:


> Davparlr,
> 
> Lets remember that this is the performance of the Do-335A-0 in 1944,



I'm confused. I used the data you presented on the first submittal that appeared was claimed for the A-1 and A-5, not the A-0. Remember the P-72 data is from early to mid 44 also.




> by mid 45 it was to powered by two even more powerful high altitude DB603 engines providing 2,700 hp each, plus a GM-1 system which would've increased the ceiling by atleast 10,000 ft.



The R-4360 engine was successfully tested at a war emergency power of 4400 hp and, since, by 1945, the production P-47N R-2800 was making 2800 hp at 33,000 ft, this is not unreasonable.



> So by mid 45 when the P-72 would've entered service in europe the Do-335 would be hitting speeds of 500 mph and climb at 5,500 ft/min. So the Do-335 P-72 would've been very close.



Since these planes were reaching the limit of propeller performance, I will agree.

I think my overall point is that the Do-335 was not a war winner in 1945 and German efforts should have emphasized the jets, in which they had a good lead. By fall of 1944, as Goering would say, the jig was up. No technology would save Germany. The advanced planes needed to be in use, in quantity, by the end of '43, early '44.


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## Soren (Dec 29, 2009)

davparlr said:


> I'm confused. I used the data you presented on the first submittal that appeared was claimed for the A-1 and A-5, not the A-0. Remember the P-72 data is from early to mid 44 also.



I presented that data because, a. WW2 ended in May 45, b. The A-1 A-5 were also built and flown during WW2 and were ready to enter service. Had the war lasted till August the Do-335 would've recieved new and more powerful engines and a GM-1 boost system. 

Now all of this would raised performance to the same level as that of the P-72, with a little extra speed climb rate to boot, but they'd be very close. 



> I think my overall point is that the Do-335 was not a war winner in 1945 and German efforts should have emphasized the jets, in which they had a good lead. By fall of 1944, as Goering would say, the jig was up. No technology would save Germany. The advanced planes needed to be in use, in quantity, by the end of '43, early '44.



Agreed.


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## red admiral (Dec 29, 2009)

Soren said:


> Furthermore Lerche says the a/c was very stable in flight, so again not sure where red admiral gets his info from, but the A-0 atleast didn't feature any of the weaknesses he claims.



If you read the quote I posted from;

Dornier Do 335: The Luftwaffe's Fastest Piston-Engine Fighter by J. Richard Smith , Eddie J. Creek and Gerhard Roletschek

you'll see the stability problems mentioned, and the porpoising at high speeds from the radiator outlet doors.


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## Soren (Dec 29, 2009)

Well the A-0 didn't feature these problems atleast, so it must have been early prototype issues.


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## drgondog (Dec 29, 2009)

davebender said:


> In my opinion the Fw-187 was superior to the Me-110 in every way. The smaller Fw-187 is probably less expensive as well. So why would the Me-110 win?
> 
> An early model tandem engine Dornier fighter is the wild card. How does a Do-334 1/2 compare with the Fw-187? Remember they have identical engines. The Dornier fighter is lighter then the historical Do-335 (no weapons bay, no 2nd crew member, lighter engine mounts for the smaller engines etc.). Can Dornier even put together a practical fighter at this early date? They do have several decades experience with tandem engine seaplanes, most of which had excellent reputations.



The discussions about the Fw 187 have always been interesting to me simply because it offered great promise as a bomber destroyer and a better long range escort fighter for medium to medium high altitude envelopes. It might have been enough to turn the tide against the RAF during the BoB.

Having said this, the specific airframe a.) offered little growth capability for gross weight (i.e more internal weapons, extra fuel, intercooler to get much better high altitude performance, and b.) was limited in versatility vs the Me 110... so the competition wasn't the Me 110 - it was the 109 and the Fw 190 and it required two engines not one.


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## Shortround6 (Dec 29, 2009)

davebender said:


> In my opinion the Fw-187 was superior to the Me-110 in every way. The smaller Fw-187 is probably less expensive as well. So why would the Me-110 win?



What was the actual armament of the FW 187 with rounds per gun of ammunition? If it is only 60 rounds per gun of cannon ammo I think we can see were some of the difference starts.

what was the range of the FW 187?

With a payload of under 3000lbs how much is available for fuel for your desired 500 mile combat radius?

you didn't answer the radio question.

to even begin to figure out what the best solution would be you need to specify what the armament load is, both guns and ammo. Figure out if a the radio needs a separate operator or not. figure out the fuel needed to fly the desired mission (radius at 300k/h or at 400k/h and at what height?) and see if all fits in the size fighter you are proposing.

The FW 187 would have made a better short range interceptor/day fighter. It would have made a lousier night fighter and/or long range over water patrol (anti anti-sub plane) and quite possibly not as good a fast fighter bomber.

same considerations for an early Do 335. What armament fit? what advantages over the 110? what disadvantages?


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## Glider (Dec 29, 2009)

drgondog said:


> The discussions about the Fw 187 have always been interesting to me simply because it offered great promise as a bomber destroyer and a better long range escort fighter for medium to medium high altitude envelopes. It might have been enough to turn the tide against the RAF during the BoB.
> 
> Having said this, the specific airframe a.) offered little growth capability for gross weight (i.e more internal weapons, extra fuel, intercooler to get much better high altitude performance, and b.) was limited in versatility vs the Me 110... so the competition wasn't the Me 110 - it was the 109 and the Fw 190 and it required two engines not one.



I mus second these points. The Whirlwind suffered a similar fate. Obviously it made it into service but with a bit of support from those in charge and a little development, both aircraft may well have achieved great things.


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## davebender (Dec 29, 2009)

> offered little growth capability for gross weight


Neither did the Me-109. Yet it served admirabily for 10 years.




> was limited in versatility vs the Me 110


We are talking about a long range bomber escort. Versitility is not a requirement anymore then it was with the P-51D.




> What was the actual armament of the FW 187


That can be tweeked to meet the specific RLM requirement. Personally I would opt for 4 x 2cm cannon in the fuselage sides. 




> what was the range of the FW 187?


That also can be tweeked to meet the RLM requirement. For one thing the space historically occupied by a second crewmember can be occupied by a second fuel tank.




> It would have made a lousier night fighter


Not part of the 1937 RLM requirement. In fact nobody had night fighters during 1937.




> Figure out if a the radio needs a separate operator or not


I don't understand the issue here. Early war Japanese escort fighters often flew with no radio at all yet they worked just fine in places like Pearl Harbor, the Philippines, Malaya, Dutch East Idies etc. Whatever radio the Fw-187 has will be at least as good as those in the A6M2.


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## Shortround6 (Dec 30, 2009)

davebender said:


> Neither did the Me-109. Yet it served admirabily for 10 years.



But not as an escort fighter, or a night fighter, or as a fighter bomber with more than a 250kg payload. 




davebender said:


> We are talking about a long range bomber escort. Versitility is not a requirement anymore then it was with the P-51D.


 We don't seem to have the range yet of the FW 187 so we don't know if it would have made a long range escort fighter. 




davebender said:


> That can be tweeked to meet the specific RLM requirement. Personally I would opt for 4 x 2cm cannon in the fuselage sides.



Nice, it that four 20mm MG/FF with a single 60 round drum apiece?
one of two 20mm guns available to the Germans in 1937-40. I don't think you want to use the other one.
Now do we solve the combat duration problem by just firing 2 guns at a time?




davebender said:


> That also can be tweeked to meet the RLM requirement. For one thing the space historically occupied by a second crewmember can be occupied by a second fuel tank.



I see, just " tweak" it. Replace 200lb crewman (including parachute) with how many lbs of fuel? 660lb of fuel keeps a SINGLE DB 601 running for how long? 




davebender said:


> Not part of the 1937 RLM requirement. In fact nobody had night fighters during 1937.



True. But what sort of pickle would the Germans have been in later when they needed night fighters and didn't have anything but converted bombers?





davebender said:


> I don't understand the issue here. Early war Japanese escort fighters often flew with no radio at all yet they worked just fine in places like Pearl Harbor, the Philippines, Malaya, Dutch East Idies etc. Whatever radio the Fw-187 has will be at least as good as those in the A6M2.



And how many Japanese planes and pilots were lost because they had no radios? 
Radios help pilots who have lost their way.
Radios help formations coordinate with each other.
Radios help formations stay in touch with base for updates or mission changes.

Some of these things maybe more important in Europe because of weather conditions than in the pacific. 
Some of these things may be more important to the Germans than to the Japanese because even the Germans may have placed a higher value on their pilots lives.
A part of the Germans success in ground combat was their more extensive use of radios compared to their opponents in the early part of the war. This use of radios was worked out pre-war. Do you think they would give up this advantage in aircraft without some very serious thought or work?

Did ALL A6M2s in a formation lack radios or did formation leaders keep theirs?
Or did the A6M2s rely on the radios in the torpedo or dive bombers they were with?


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## drgondog (Dec 30, 2009)

davebender said:


> We are talking about a long range bomber escort. Versitility is not a requirement anymore then it was with the P-51D.
> 
> *Well, the P-51 started out as basically a pure fighter with great speed, low to medium altitude performance better than the P-40, limited harpoint capability to 500 pounds.. transitioned to perform low altitude Recce, dive bomber with brakes, transitioned to high altitude escort, grew hard point capability to 1000 pounds for tactical, more for ferry tanks. Redesigned to same basic lines different structure, grew to twin fuselage all weather interceptor and night fighter..
> 
> ...



Long Range escort mission requires a VERY good radio. Even the Mustang which a had a very good four channel radio - required a Radio Relay flight orbiting over the Channel to pass messages from Beachy Head to the Escort - while they maintained comm between themselves and the bombers.


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## Erich (Dec 30, 2009)

too big, too bulky not enough time, the TA and the 262 would of been used full time in the LW arsenal and probably 2 other jets during 1946 if it was to be, this is all recorded in LW documentation towards wars end. buried at the Freiburg archiv's incase those wish to visit and really explore, but first one must find the RL numerations to proceed, don't ask me, as the Do does not interest me in the slightest but the info is there


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## parsifal (Dec 30, 2009)

According to my book "Zero-A6M" by HP Willmott, Zeroes at no stage did not have radios fitted. They suffered some downgraded performance (which hads been grossly overstated in some accounts) because they did not put suppressors in their high tension leads until 1944, and because as the war progressed, build quality dropped. There were some occasions where individual pilots of land based air groups did remove radios, to reduce weight 

Its a very good bet that if Zeroes werre always fitted with radios, then nearly every other type in the japanese inventory also carried radios.


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## Burmese Bandit (Jan 17, 2010)

And now a question which, I believe, no one has ever asked before.

What if...

Dornier had been struck by a sudden epiphany, and thought:

"The rear engine of my two engine design was always the more efficient position, anyway. Why not put both props at the rear, on a co-axial contra rotating prop, and leave the nose completely free for vision and armament?"

As in:

The experimental Douglas XB-42 Mixmaster. (see wiki)

Even with the fat body of a bomber, the Mixmaster at 35,000 lbs and a 70 foot wingspan got over 400 mph and could fly well over 2400 miles with a warload (ferry range was an astounding 5400 miles). The power, two 1800 Allisions, is almost an exact mirror image of the two 603s in the Do 335. 

Utilizing the Mixmaster concept, we could design a slimmer bodied Dornier with 440 mph and 60 foot wingspan and a central bomb bay that could take at least 6600 lbs of bombs (The Mixmaster could take 8000 lbs) or four Mk 103 long range high velocity 30mm cannon with PLEN TY of ammo. And of course at least 1500 mile range (the Mixmaster had 2500 mile range)

Roles: 

Long range, high speed bomber destroyer - check.
Long range, high speed tank killer - check. 
Long range high speed torpedo bomber with at least two torpedoes - check.
Long range high speed highly survivable night bomber - check.
Long endurance, high speed, heavily armed night fighter - check. Even with the ineffecient high drag German radar antennae it could probably do 390-400 mph. 

Your opinions, gents?


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## davebender (Jan 17, 2010)

More complex = longer research development time. And time is one luxury late 1930s Germany does not have. 

Better to begin development of the Do-335 (or something similiar) during 1938 and have it in service by 1942. It will compete with and beat the Me-210 in the RLM competition for an improved zerstorer.

Powered by a pair of readily available DB601 / DB605 engines. Top speed will continue to increase as new models of the DB605 engine enter service. However the Do-335 will always have a 50+mph speed advantage over most contemporary fighter aircraft.


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## Shortround6 (Jan 17, 2010)

davebender said:


> Powered by a pair of readily available DB601 / DB605 engines. Top speed will continue to increase as new models of the DB605 engine enter service. However the Do-335 will always have a 50+mph speed advantage over most contemporary fighter aircraft.



Do you want to explain this 50+ mph speed advantage?


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## parsifal (Jan 17, 2010)

Yes, seems a little odd, considering the MB 157 flew in early 1941 with a top speed in excess of 440 mph


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## Colin1 (Jan 17, 2010)

davebender said:


> However the Do335 will always have a 50+mph speed advantage over most contemporary fighter aircraft


The Do335
appeared to have a comfortable speed advantage over both the P-47 and the Tempest V, I use these two as they are the only two aircraft of which I have read ever making contact with the Dornier fighter; neither could close on it to gunnery range.

I'm not sure the Do335 enjoyed a 50mph+ speed advantage over the P-47M or the Tempest though.

The point here is the scarcity of operational sorties flown by the type owing to the imminent closure of hostilities, yet if the war had continued for another year then it would have encountered the P-51H, some land-based derivative of the Sea Fury, possibly the MB.5 at which point it would likely have been stuffed: its tactical advantage, its speed, has been nullified, it was a big aircraft and I can't see it trading blows with a P-51H for long in a furball.

The same year would have seen Allied jet technology come to some meaningful fruition too.


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## Shortround6 (Jan 18, 2010)

Part of the problem in comparing the Do-335 to allied fighters is that the comparison is between what are essentially prototypes and squadron service aircraft. American and to some extent British aircraft in late 1944 and 1945 in Europe are going to be several months behind German aircraft because of testing, getting into production and issuing in squadron numbers, Including squadron training time with new aircraft and transit times of squadrons/groups to combat areas and the Allied aircraft are going to be several months behind Germans aircraft that are produced and flown as prototypes or in small numbers.


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## davebender (Jan 18, 2010)

*Assumption.*
Do-335 (or something similiar) enters service during January 1942 powered by 2 x 1,350 hp DB601 engines (same as Me-109F). Total hp = 2,700. Max speed = 425 to 450 mph.
*
Contemporary Fighter Aircraft.*
~400 mph. Me-109F.
~398 mph. MiG3.
~395 mph. P-38E.
~375 mph. Spitfire Mk V.
~360 mph. P-40E.


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## Colin1 (Jan 18, 2010)

davebender said:


> *Assumption.*
> Do-335 (or something similiar) enters service during January 1942...


Umm, you sneaked that one in late


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## parsifal (Jan 18, 2010)

No, hes been saying the Do-335 could be ready as early as 1937 if only they had tried.

What about the MB 157, with a top speed of over 447 missing from the list.......


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## Vincenzo (Jan 18, 2010)

maybe because was only a experimental fighter and there were some reason why the lw blocked him development, as not best of other experimental fighters?


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## davebender (Jan 19, 2010)

Not operationally ready. The necessary technology was patented during 1937. 

As far as I can tell the Do-335 had no major development issues (unlike the Me-210 and Fw-190). If Do-335 development begins in 1938 as a competator to the Me-210 program it will enter service by early 1942. The 1938 version would be a bit smaller and lighter as it uses the smaller DB601/DB605 engines. Performance should still be excellent even with only 2,700 total hp.


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## Colin1 (Jan 19, 2010)

davebender said:


> Performance should still be excellent even with only 2,700 total hp.


Only?
That's alot of horses for the configuration offered by the Do335, with a frontal area probably on a par with the P-47


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## riacrato (Jan 19, 2010)

You keep bashing on the Fw 190, I don't know why. The Fw development was pretty straight forward, only real problem being overheating in the early phase, which is not so surprising considering the novelty/lack of experience with the cooling concept. The Do 335 as flown by EK 335 had a lot of smaller to larger issues, many of which easily match the cooling problem of the Fw.


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## comiso90 (Jan 19, 2010)

I cant think of the Do335 w/o the Shinden jumping to mind...

They had similar numbers.. from what I read, the Do 335 was faster but the Shinden had a higher ceiling..

which was a better climber?


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## davebender (Jan 19, 2010)

I like the Fw-190 just fine. I don't like the BMW801 engine.

The whole point of an early Do-335 is to achieve superior performance using readily available DB601/605 engines. Dornier has experience with tandem engine aircraft going back to WWI. So why not let them enter a tandem engine heavy fighter to compete for the zerstorer role?


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## riacrato (Jan 19, 2010)

Providing sufficient cooling is a task for the engine supplier as well as the aircraft company. The Fw 190 cowling was exceptionally tight-fit, much tighter than with then-typical radial aircraft.

FW and BMW continuously blamed each other for the problem. In the end, it was solved by changing the engine as well as the fuselage.


The Do 335 had cooling problems with its DB603s as well, at least in the pre-production models. The frontal engine cooling flap control was insufficient, resulting in several cases of the unusual type of cooling problems ("too cold"). The rear engine had the opposite problem: It ran too hot. In fact (iirc) this was one reason the DB603E wasn't installed in this position on the pre-production aircraft. Similar problem as the Fw 190. Now do you blame DB or Dornier?

BTW, it's true that Dornier has experience with pull-push aircraft. But (I'm not an engineer), I assume it's a significant difference if the engines are right behind each other on top of a wing, or if they are on the opposite ends of the aircraft. Also consider the power (and forces, stress) that the few hundred hp engines of the early flying boats put on compared to 1800 hp DB603s.


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## davebender (Jan 19, 2010)

Dornier Do 18 - Wikipedia, the free encyclopedia
_Do 18G 62 built, was an improved version, powered by two 656 kW (880 hp) Jumo 205D engines_

Jumo 205D produces 880 hp.
Early model DB601 produces 1,100 hp.

That's not such a huge leap. More like the next logical step in the evolution of Dornier tandem engine aircraft.


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## barney (Jan 19, 2010)

parsifal said:


> According to my book "Zero-A6M" by HP Willmott, Zeroes at no stage did not have radios fitted. They suffered some downgraded performance (which hads been grossly overstated in some accounts) because they did not put suppressors in their high tension leads until 1944, and because as the war progressed, build quality dropped. There were some occasions where individual pilots of land based air groups did remove radios, to reduce weight
> 
> Its a very good bet that if Zeroes werre always fitted with radios, then nearly every other type in the japanese inventory also carried radios.



Saburō Sakai, in his book, in listing his and his air goup's activities in the New Guinea campaign, and I have his book floating around here somewhere, writes that they used neither radios nor parachutes. They disdained anything that would reduce the performance of their aircraft.


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## Shortround6 (Jan 19, 2010)

davebender said:


> I like the Fw-190 just fine. I don't like the BMW801 engine.
> 
> The whole point of an early Do-335 is to achieve superior performance using readily available DB601/605 engines. Dornier has experience with tandem engine aircraft going back to WWI. So why not let them enter a tandem engine heavy fighter to compete for the zerstorer role?



The Zerstorer role may have required a the standard long range radio which required a separate radio operator. In 1939-40 the Germans didn't have any reliable engine mounted guns and the only synchronized gun they had was the MG 17. With only MG 17s available for cowl/wing root positions the plane would have been rather lightly armed. Mounting MG/ffs in the wing would have limited them to 60 rounds apiece without development of a larger drum. The 110 used the radio operator as a loader to change drums on the fuselage mounted 20mm MG/FFs.


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## davebender (Jan 19, 2010)

> In 1939-40 the Germans didn't have any reliable engine mounted guns


That's a matter of financial priority.

Bismarck Information
KM Bismarck cost 197 million marks during 1936. Divert 10% of that amount into aircraft cannon R&D and Luftwaffe fighter aircraft will all be armed with the MG151/20 cannon by 1940. Perhaps the MG213 revolver cannon will even enter service before the end of the war.


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## Shortround6 (Jan 19, 2010)

davebender said:


> That's a matter of financial priority.
> 
> Bismarck Information
> KM Bismarck cost 197 million marks during 1936. Divert 10% of that amount into aircraft cannon R&D and Luftwaffe fighter aircraft will all be armed with the MG151/20 cannon by 1940. Perhaps the MG213 revolver cannon will even enter service before the end of the war.



And if the US had simply shortened the chamber of the 20mm Hispano cannon made in the US to match the British specifications the US could have had fighter planes armed with reliable batteries of four 20mm cannon in 1943. 

It is not always just money, it seemed to take 4-6 years for just about any nation to develop a new aircraft gun. Making a truck load of prototypes instead of 2 or 3 doesn't speed things up if there is a fundamental flaw in the original design, you just have truck load of very expensive junk. You can't make production tooling until the design is finalized. Well you can but please look at the number of tanks and aircraft that were ordered "off the drawing board". How many were successful? How many were a disaster? how many were mediocre?


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## davebender (Jan 20, 2010)

> And if the US had simply shortened the chamber of the 20mm Hispano cannon made in the US to match the British specifications the US could have had fighter planes armed with reliable batteries of four 20mm cannon in 1943


It's a matter of design experience. Germany was mass producing a 20mm aircraft cannon in 1916. by 1936 they have 20 years experience. Long enough to have a bunch of engineers familiar with designing 20mm aircraft cannon.

When did the USA produce their first 20mm aircraft cannon? Fixing the 20mm Hispano cannon may have been a simple thing but not if you have no engineers familiar with such things.


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## riacrato (Jan 20, 2010)

I don't think in this case it matters that much if the gun's a cannon or a heavy mg. Chamber is chamber. And the US had vast experience with heavy mgs and their ammunition.

I think the point Shortround is making is that r&d is no simple equation. You can't substitute x years with y million dollars. Not to mention that under wartime conditions, monetary comparisons are futile. Building a Bismarck costs steel and labour. Developing a cannon requires labour, but of a completely different kind.


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## Shortround6 (Jan 20, 2010)

davebender said:


> It's a matter of design experience. Germany was mass producing a 20mm aircraft cannon in 1916. by 1936 they have 20 years experience. Long enough to have a bunch of engineers familiar with designing 20mm aircraft cannon.
> 
> When did the USA produce their first 20mm aircraft cannon? Fixing the 20mm Hispano cannon may have been a simple thing but not if you have no engineers familiar with such things.



OK, what was the mass produced 20mm cannon in 1916? the Becker?

You might want to check the MG 204 and the MG C/30L for some examples of German 20mm guns that didn't work so well. 

The point about the Hispano was that the British had ALREADY fixed it. Just use the existing British drawings, no research, no development, no money spent, no engineers needed.

You not only want new aircraft designs but new guns to go with them, new radios and who knows what else to get your proposals to work.


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## davebender (Jan 20, 2010)

Was it acceptable to U.S. methods of mass production? We spent a lot of design effort on the RR Merliin engine and Bofors 40mm cannon before they could be produced in American factories.

A similiar re-design effort failed when the U.S. attempted to copy the German MG-42 machinegun. A weapon that worked just fine in the original German version.


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## Shortround6 (Jan 20, 2010)

davebender said:


> Was it acceptable to U.S. methods of mass production? We spent a lot of design effort on the RR Merliin engine and Bofors 40mm cannon before they could be produced in American factories.
> 
> A similiar re-design effort failed when the U.S. attempted to copy the German MG-42 machinegun. A weapon that worked just fine in the original German version.



Just how does shortening the chamber length make the entire gun different to produce by mass production? You just don't run the reamer in all the way or you use a slightly shorter reamer. 

Just what did we do the Merlin engine to make it producible in American factories? Just about ALL major parts were interchangeable with the British built engines. We may have used different manufacturing techniques to build the parts but that is not quite the same as modifying the parts. 
By the way, some American factories used different manufacturing techniques to build American engines than the parent factory did. It depended on the expertise of the particular company/factory involved. 

Speaking of expertise, that was part of the problem with the American effort to copy the MG-42. The company involved had never built a gun a before. As the story goes, they forgot (failed to understand) that the American 30-06 case was 6mm longer than the German 8mm case and failed to make the ejection slot big enough. Machine guns don't work very well if the empty cases can't get out of the gun. By the time the goof was caught not enough time was left to the war to make adopting a new gun worthwhile.


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## davebender (Jan 20, 2010)

_Just what did we do the Merlin engine to make it producible in American factories?_
Packard V-1650 - Wikipedia, the free encyclopedia


> The initial Packard modifications were done on this engine by changing the main bearings from a copper lead alloy to a silver lead combination and featured indium plating. This had been developed by General Motors' Pontiac Division to prevent corrosion which was possible with lubricating oils that were used at that time. The bearing coating also improved break-in and load-carrying ability of the surface. British engineering staff assigned to Packard were astonished[citation needed] at the suggestion but after tear-down inspections on rigidly tested engines were convinced the new design offered a decided improvement.
> 
> The real improvement Packard incorporated into the Merlin was adopting the Wright supercharger drive quill. This modification was designated the V-1650-3 and became known as the "high altitude" Merlin destined for the P-51. The two speed, two stage supercharger section of the -3 featured two separate impellers on the same shaft which were normally driven through a gear train at a ratio of 6.391:1. A hydraulic gear change arrangement of oil operated clutches could be engaged by an electric solenoid to increase this ratio to 8.095:1 in high speed blower position. The high speed gear ratio of the impellers was not as great as the ratio used in the Allison but speed of the impeller alone was not the factor that increased the engine performance at altitude.[clarification needed] The double staging of the compressed fuel/air mixture provided the boost pressure through a diffuser to the intake manifolds which increased the critical altitude of the power plant.
> 
> ...


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## parsifal (Jan 20, 2010)

In the overall scheme of things this is not a major redesign of the merlin engine. They used different bearing and a different supercharger. This is not a big deal...they did not have to change the engine geometry, the crank, the pistons, the ignition timing even.....have done similar modification to car engines myself in a previous life.....


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## Glider (Jan 21, 2010)

comiso90 said:


> I cant think of the Do335 w/o the Shinden jumping to mind...
> 
> They had similar numbers.. from what I read, the Do 335 was faster but the Shinden had a higher ceiling..
> 
> which was a better climber?



For some reason I hadn't realised what a big aircraft the 335 was. That soldier looks tiny by comparison


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## davebender (Jan 21, 2010)

> In the overall scheme of things this is not a major redesign of the merlin engine.


It depends on how you define "major". The Japanese copy of the DB601 engine (Ha-40) failed because of problems manufacturing reliable crankshaft bearings. Most nations except Britain and Germany appear to have had serious problems with aircraft engine supercharger systems. 

Packard got both of these items right when they copied the RR Merlin engine. IMO that's a noteworthy achievement.


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## Shortround6 (Jan 21, 2010)

davebender said:


> _Just what did we do the Merlin engine to make it producible in American factories?_
> Packard V-1650 - Wikipedia, the free encyclopedia



Packard used different bearings and a different supercharger drive system, nothing there about different manufacturing techniques is there? and using a different bearing material, while an improvement, isn't really HAVING to adopt different manufacturing techniques is it?

The last three paragraphs have nothing to do with any differences between American Merlins and British Merlins and the second paragraph aside from the first sentence could equally be describing a British 60 series Merlin. 

Packard was the first to manufacture a separate cylinder head Merlin but the engineering had already been done, Packard was just in a better position to incorporate the change without a disruption in manufacturing/delivery schedules.


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## davebender (Jan 21, 2010)

The romance of engines - Google Books

Here is the information on the Ha-40 engine problems. I miss-spoke concerning the reason for Ha-40 engine failure. Apparently the Japanese had difficulty heat treating the engine crankshaft. This caused excessive wear within 100 running hours.

Packard had a well deserved reputation for building high quality engines. Their copy of the RR Merlin was as good or better then the original. It's a good thing they weren't located in Japan or the Pacific skies might have been full of Ki-61s powered by reliable DB601 engine clones. 8)


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## drgondog (Jan 21, 2010)

Shortround6 said:


> OK, what was the mass produced 20mm cannon in 1916? the Becker?
> 
> You might want to check the MG 204 and the MG C/30L for some examples of German 20mm guns that didn't work so well.
> 
> ...



Dead on Shortround - IIRC the RAF had to scrap a lot of 20mm ammo we sent them, in addition to the problem that our 20mm had headspace problems that they kept telling us about.

I wonder if Adm King was the prob on our side?


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## drgondog (Jan 21, 2010)

Shortround6 said:


> Packard used different bearings and a different supercharger drive system, nothing there about different manufacturing techniques is there? and using a different bearing material, while an improvement, isn't really HAVING to adopt different manufacturing techniques is it?
> 
> The last three paragraphs have nothing to do with any differences between American Merlins and British Merlins and the second paragraph aside from the first sentence could equally be describing a British 60 series Merlin.
> 
> Packard was the first to manufacture a separate cylinder head Merlin but the engineering had already been done, Packard was just in a better position to incorporate the change without a disruption in manufacturing/delivery schedules.



NAA did have to go outside to also fix the radiator core oxidation issues with the new Packard Design IIRC


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