Do 335

[bob44]

Lets talk of the pros and cons of this aircraft.
Was it a necessary aircraft for Germany? Or just another late war hope? Too little, too late.
I have read many "reports/stories" about the 335.
How bout some accurate reports form the Germans and post war Allies.

 

[pattern14]

No-one seems interested in this subject so far, which seems strange, being such an innovative aircraft. Fastest piston engine luft aircraft ( faster than the Ta 152, although not operational) and "probably " the fastest piston engined aircraft of its time ( wait for the chorus of "no way, this X plane was faster...etc etc.) It does not seem to have any post war copies or derivatives that I know of, although Dornier was working on swept wing versions. Like the He 162, it seemed destined for the Museum of desperate German curiosities. Hopefully some one else out there will chime in with some interesting facts and figures.

 

[GregP]

We're interested, but we already DID this one ... in some depth, not too long ago. Maybe the rank and file are not up to doing again in a relatively short time.

Some feel the Do 335 was a good way to go, many didn't. It was NOT a fighter that was maneuverable with others ... but opinions vary here. It rolled well, but would never pitch with a single-engine fighter with the two large masses on either end. It had explosives in the rear to blow away the fin and prop for bail out ... right in the path of incoming fire from behind. The high speeds were at WER power ... that was almost never used. So the REAL speeds were closer to low-to-mid 400 mph range.

Lots of arguments here, both pro and con. But, nobody ever made a successful warplane of the general type, so it seems like a dead end. That CAN be argued, but not very successfully.

I like it as an exercise but maybe would have censurd the designer who wasted resources on it in Germany when the need was for practical aircraft. The population was ridiculously small and ineffective due to being prototypes near the end of the war.

 

[pattern14]

We're interested, but we already DID this one ... in some depth, not too long ago. Maybe the rank and file are not up to doing again in a relatively short time.

Some feel the Do 335 was a good way to go, many didn't. It was NOT a fighter that was maneuverable with others ... but opinions vary here. It rolled well, but would never pitch with a single-engine fighter with the two large masses on either end. It had explosives in the rear to blow away the fin and prop for bail out ... right in the path of incoming fire from behind. The high speeds were at WER power ... that was almost never used. So the REAL speeds were closer to low-to-mid 400 mph range.

Lots of arguments here, both pro and con. But, nobody ever made a successful warplane of the general type, so it seems like a dead end. That CAN be argued, but not very successfully.

I like it as an excersize but maybe would have censurd the designer who wasted resources on it in Germany when the need was for practical aircraft. The population was ridiculously small and ineffective due to being prototypes near the end of the war.

Hi GregP; I did not realise that this one had been already discussed in depth previously, and I thought the poor fellow was being overlooked! No arguments about the Do335; if it had had potential, someone would have picked it up and ran with it post war.

 

[GrauGeist]

There's actually dozens of threads spanning years on the forum here regarding the Do335.

It was fast, there is no doubt about it. But it had limitations as far as what it could do.

The Pfeil was big, expensive to make and would have been best suited for bomber intercepting *if* it had top cover nearby to keep escorts off it's back. It could have also been a high-speed photo-recon aircraft...though an expensive one.

It was pretty much an evolutionary dead-end in the grand scheme of things...

 

[OldSkeptic]

Silly design. There were no advantages of the pusher/tractor design and a heck of a lot of disadvantages.

It was not faster than, say, a DH Hornet, which would have ran rings around it and been simpler to build, maintain and use.
Also Tank's own estimates for a later developed Ta-154 put that well into the 460mph class. And again simpler to build, maintain and use.

Why the Luftwaffe tolerated this nonsense from the manufacturers sod only knows. Why, say, cancel the Ta-154 and waste scarce resources on this pig????
Then again, from the Allied point of view, having them running around throwing away resources into 'hyper' engines that never worked, 'hyper' planes that also never worked, helped us a lot.

There have been a lot of daft aircraft designs over the years ... this was one of them...

 

[nuuumannn]

No-one seems interested in this subject so far,

Enter "Dornier Do 335" into the Search function at top right and see what you come up with.

 

[tomo pauk]

Silly design. There were no advantages of the pusher/tractor design and a heck of a lot of disadvantages.

Exceptional desing that arrived too late to matter. Another problem is use of rare DB-603, rather than widely available DB-601-605 and/or Jumo 211, of course provided the plane of similar layout is produced in early- or mid-war.
The advantages: far less drag than 'classic' twin; the Pfeil was much faster than Me-410 on same engines. With one engine out there is no asymmetric thrust. The engines at centerline do not hamper roll rate, unlike the engines mounted away from centerline (at wings).
Disadvantages are the need to have the extension shaft, while the pilot needs to have a safe system of leaving the moving aircraft. The Western aircraft with such layout will need to have all/most of the weponry in the wings, not an issue for German or Soviet (there was none) aircraft of push-pull layout.

It was not faster than, say, a DH Hornet, which would have ran rings around it and been simpler to build, maintain and use.

Hornet was using engines of 1945, Pfeil was using engines of 1943. Let's have the Hornet outfitted with Merlin 66 and see how it compares with Pfeil and historical Hornet. In the meantime, the Pfeil also has a bomb bay to offer.

Also Tank's own estimates for a later developed Ta-154 put that well into the 460mph class. And again simpler to build, maintain and use.
Why the Luftwaffe tolerated this nonsense from the manufacturers sod only knows. Why, say, cancel the Ta-154 and waste scarce resources on this pig????

If Tank was really talknig that (estimates for it's own product), that alone raises a suspicion alert. For example, the estimate for the speed of the Fw-190A-3 (it's BMW working okay there) was 700 km/h, vs. 660 actually achieved. So, yes, cancel the Ta-154 and make two Ta-152s or Bf-109Ks for each of Ta-154 and Do-335 not built, they use only one engine.
The story of the Ta-154 is a really sad one, indeed.

Then again, from the Allied point of view, having them running around throwing away resources into 'hyper' engines that never worked, 'hyper' planes that also never worked, helped us a lot.
There have been a lot of daft aircraft designs over the years ... this was one of them...

Compared with other mistakes Germans (and others) made during ww2, the Do-335 looks like a flawless execution on the theme 'fast well armed 2-engine combat aircraft'.

 

[davebender]

Apparently not since Germany had no plans to place the Do-335 into mass production during 1945.

It appears to me Do-335 and Me-163 rocket powered interceptor were developed to test new technology and to provide an alternate solution in case jet engines didn't pan out.

 

[GregP]

As far as I know, the Do-335 never fired a shot in anger or dropped a bomb in anger. The Allies encountered one with a flight of four Tempests and they were not able to catch it ... so it also didn't have a loss in wartime due to enemy aircraft action.

They built a total of 37.

I don't call 37 aircraft with no war record exceptional in any manner. Innovative? yes. Had potential? Maybe and probably? Made a dofference? No. Was it good? It was fast with MW-50 boost. That does not mean it was good at anything else much, but it might have been. We don't know much about it actually.

I rather like it as a fast bomber used in a Mosquito sort of way. But not as a fighter ... I think it would have been rather ineffective at that based on poor pitch rate with two heavy masses on either end. These are my opinions and I might be wrong, but there is no proof for or against that as far as I know. Others may and probably do have different opinions.

But without a war record, there is little to argue about concerning this interesting machine.

 

[OldSkeptic]

Exceptional desing that arrived too late to matter. Another problem is use of rare DB-603, rather than widely available DB-601-605 and/or Jumo 211, of course provided the plane of similar layout is produced in early- or mid-war.

So exceptional a design, no one has every copied it ever since....
Anyone that depended on the 603 was being a bit naive. DB used it more as a political ploy to stuff up Jumo than anything else.
With 605's it would have been slower ... slower than a Hornet with Merlin 66's perhaps...

The advantages: far less drag than 'classic' twin; the Pfeil was much faster than Me-410 on same engines. With one engine out there is no asymmetric thrust. The engines at centerline do not hamper roll rate, unlike the engines mounted away from centerline (at wings).

Nope that is a matter of design. As per the Hornet .. and every modern prop twin that has ever been built since WW2.
Roll rate is up for grabs. Because you don't get the lift from the propwash over the wings you need much larger wings for takeoff and climb, which increase drag and reduce roll rate. The P-38 showed the way, with boosted ailerons.
No one complained about the Hornet's roll rate ...

Disadvantages are the need to have the extension shaft, while the pilot needs to have a safe system of leaving the moving aircraft. The Western aircraft with such layout will need to have all/most of the weponry in the wings, not an issue for German or Soviet (there was none) aircraft of push-pull layout.

Plus heat build up issues, radiator issues (you need 2 of them or one big one, either option with complex (and heavy) plumbing issues, then fuel safety issues pumping fuel into a hot engine bay ... and so on.
Plus the solution to the little matter of a the pilot/crew getting out depended on an explosive blowing off the rear tail....
Right this is a warplane, where the most common attack will be from the rear ... and it is full of explosives..

Other disadvantages: (1) a very long plane, with all the take off, stability, CoG, maneuverability issues to be overcome, this plane is not going to be a turner (2) as mentioned, no propwash over the wing, therefore a larger wing = roll issues, more weight and drag and so on (3) maintenance, I can just see an engineer coming to work on the engines going "and what f*kwit thought this abortion up" (4) engine bay heat issues, a very hot area indeed, you either cool it more = complexity, drag and weight or let it run hot and risk fires ... which killed the pilot who flew it after Eric Brown did.

Looking around the skies for tractor/pusher designs these days wither civilian or military ... and can't find any.

As I said in the first time this topic came up, it was far easier to solve the straightforward issues of reducing drag and increasing roll rates for a traditional twin tractor engines in the wing, than try to solve a whole new bunch of issues for a very iffy design. Or in other words, if you could (like DH and others did) reduce the drag of the engine nacelles in the wing then you will get, at least, the same speed performance, plus you avoid so many other issues, like the ones mentioned above.

[Related to the Issues, ignore if you want]
I see this as a classic case of design monomania, fixating one one issue. But instead of coming up with a solution and then, instead of bouncing it around and working through the issues, then rejecting it and the focusing on the real issues, they went and tried to make it?
Many of the issues of the design are blindingly obvious and unless you can come, right at the beginning, with effective solutions then you start again with a clean sheet of paper.

But at least it kept them from having to make 190s or Ju-88s, kept them busy, in a job having a bit of a lark on Govt money, that's being very cynical but I'll bet it was one of the motivations. Just as was DB's one to stuff up Jumo, promising the earth to get a (forgotten the name) purpose built factory and all the contracts, with zero intention of ever delivering. Just edging out Jumo was good enough for them, because it meant that their 605 sales were guaranteed then, the fact the the 605 was way past its use by date by then (by German design criteria) and it meant that their fighters and bombers were going up against seriously superior power levels was irrelevant to them. They Had Won and seen off a competitor.

Must admit I do have a bit of soft spot for Jumo as an engine maker, even though they also succumbed to the 'promising the Earth and never delivering' syndrome of the time. But at least they tried to match RR and the others in the advanced engine stakes on something like a rational basis, though my personal favorite was BMW, after the usual teething issues and development that 801 was a heck of good engine.

 

[Milosh]

Looking around the skies for tractor/pusher designs these days wither civilian or military ... and can't find any.

http://upload.wikimedia.org/wikipedia/commons/f/ff/Cessna_Skymaster_O-2_5.jpg

 

[davparlr]

So exceptional a design, no one has every copied it ever since....

Not really fair since the jet engine quickly obsoleted high performance propeller driven fighters of all configurations.


The Do-335 was a reasonable attempt to get the maximum amount of horsepower with a minimum of drag. According to Wikipedia it performed similarly to Hornet with 400 less hp. It was, however, a day late and a dollar short. The US had already started operations with the powerful P-47M/N and had cancelled the production program for very powerful and impressively performing P-72.

 

[tomo pauk]

So exceptional a design, no one has every copied it ever since....
Looking around the skies for tractor/pusher designs these days wither civilian or military ... and can't find any.

Covered in 'sandwiched' posts. BTW, during all Cold war and after, only a handful of jet-engined combat airplanes featured wing-mounted engines either.

Anyone that depended on the 603 was being a bit naive. DB used it more as a political ploy to stuff up Jumo than anything else.

Doh. DB-603 was a far earlier design, flying in combat aircraft a good year prior that was true for the Jumo 213.

With 605's it would have been slower ... slower than a Hornet with Merlin 66's perhaps...

With DB-601/605 the whole airplane would've been far smaller and lighter, unlike the Hornet with M.66s.

Nope that is a matter of design. As per the Hornet .. and every modern prop twin that has ever been built since WW2.
Roll rate is up for grabs. Because you don't get the lift from the propwash over the wings you need much larger wings for takeoff and climb, which increase drag and reduce roll rate. The P-38 showed the way, with boosted ailerons.
No one complained about the Hornet's roll rate ...

There is/was no designer that was able to magically wave off the fact that you have two 1-ton power-plants (engine, cooling, prop, oil, water..) mounted 8-10 ft away from centerline. P-38 showed the way for roll rates at high speeds, once boosted ailerons were installed, but the roll rates at low speed remained low.
The wing of the Do-335 was about the same size of the Mosquito, the 3 cannons were carried, the bomb bay was capable to hold up to 2200 lbs, the airplane was good for 460 mph. Seem like a good trade off, re. wing size; the Me-410 was far slower despite smaller wing.

Plus heat build up issues, radiator issues (you need 2 of them or one big one, either option with complex (and heavy) plumbing issues, then fuel safety issues pumping fuel into a hot engine bay ... and so on.

There were two engines per each Do-335, so two radiators seem okay
Reliable informations confirming 'complex and heavy plumbing issues' would be welcomed, as well as 'fuel safety issues pumping fuel into a hot engine bay'.

Plus the solution to the little matter of a the pilot/crew getting out depended on an explosive blowing off the rear tail....
Right this is a warplane, where the most common attack will be from the rear ... and it is full of explosives..

Germans were outfitting the He-219 with eject seat, so there lays a solutin for non-explosive rear end. But, full of explosives???

Other disadvantages: (1) a very long plane, with all the take off, stability, CoG, maneuverability issues to be overcome, this plane is not going to be a turner (2) as mentioned,

Where I can read a credible information about 'all the take off, stability, CoG, maneuverability issues' that Do-335 was facing? Who says it won't be a turner? Seem like people don't see that a Do-335 (and other similar planes) during a take off will have less risk to crash in case of engine failure.

no propwash over the wing, therefore a larger wing = roll issues, more weight and drag and so on

Design it around DB-601/605 or Jumo-211, forget the bomb bay and you don't gave to have a big wing. Again, I'll like to see what plane with heavy punch and a bomb bay was capable to do 460 mph.

(3) maintenance, I can just see an engineer coming to work on the engines going "and what f*kwit thought this abortion up" (4)

A pilot in a plane that is capable for 370-390 mph at 25000 in 1944 (read: Bf-109G, Fw-190A) will not have anything to say, curses maybe, since he is too busy to fend off the 430-440 mph P-51 or P-47. The P-38 was utterly maintenance-unfriendly, yet nobody that flew it claimed 'I want P-40, not this complicated thing'. Nobody asked mechanics, they did their job as good as possible.

engine bay heat issues, a very hot area indeed, you either cool it more = complexity, drag and weight or let it run hot and risk fires ... which killed the pilot who flew it after Eric Brown did.

The Do-335 was pushing the envelope for the piston engined fighters. Expecting it to be flawless in just every area is unrealistic.

As I said in the first time this topic came up, it was far easier to solve the straightforward issues of reducing drag and increasing roll rates for a traditional twin tractor engines in the wing, than try to solve a whole new bunch of issues for a very iffy design. Or in other words, if you could (like DH and others did) reduce the drag of the engine nacelles in the wing then you will get, at least, the same speed performance, plus you avoid so many other issues, like the ones mentioned above.

MTT tries with 210/410, they did not went very far. Again, comparing the fighter that was using 1945 engines, and was without a bomb bay, with a plane with 1943 engines and a bomb bay is comparing apples and oranges.

[Related to the Issues, ignore if you want]
I see this as a classic case of design monomania, fixating one one issue. But instead of coming up with a solution and then, instead of bouncing it around and working through the issues, then rejecting it and the focusing on the real issues, they went and tried to make it?

Seems my understanding of English is a bit under-strength to understand this properly? The bolded sentence is a bit tough for me to understand.

Many of the issues of the design are blindingly obvious and unless you can come, right at the beginning, with effective solutions then you start again with a clean sheet of paper.
But at least it kept them from having to make 190s or Ju-88s, kept them busy, in a job having a bit of a lark on Govt money, that's being very cynical but I'll bet it was one of the motivations.

Was it maybe that you've forgot the Do-217, a far more capable bomber than Ju-88?

Just as was DB's one to stuff up Jumo, promising the earth to get a (forgotten the name) purpose built factory and all the contracts, with zero intention of ever delivering. Just edging out Jumo was good enough for them, because it meant that their 605 sales were guaranteed then, the fact the the 605 was way past its use by date by then (by German design criteria) and it meant that their fighters and bombers were going up against seriously superior power levels was irrelevant to them. They Had Won and seen off a competitor.
Must admit I do have a bit of soft spot for Jumo as an engine maker, even though they also succumbed to the 'promising the Earth and never delivering' syndrome of the time. But at least they tried to match RR and the others in the advanced engine stakes on something like a rational basis, though my personal favorite was BMW, after the usual teething issues and development that 801 was a heck of good engine.

German engine development was surely a story with many mishaps and designers/manufacturers promising what they cannot deliver. Eg. Jumo-222 was a sad story. Just how the Jumo 'tried to match RR and others' is a mystery to me, care to elaborate a bit? BMW was never outfitted with two-stage compressor, BTW; the DB being Germany's 1st to make a two-stager.
The DB's 'zero intention of ever delivering' could also use some reliable data to confirm it.

 

[GrauGeist]

Just a quick note regarding OldSkeptic's comment about push-pull configurations.

There's several out there that are modern builds, the Cessna Skymaster is the first that comes to mind. There's also a fairly attractive commuter made by Adam Aircraft, the A500.

 

[tomo pauk]

An excerpt from the Do-335 page at Smithsonian's museum web site:

Unlike conventional twin-engine aircraft with wing-mounted engines, the Do 335 would not yaw sharply to one side if one engine failed, and single-engine flying speed remained respectable at about 620 km/h (345 mph). Pilots reported exceptional flight performance in acceleration and turning radius, and docile handling with no dangerous spin characteristics. In an emergency, however, the pilot could detonate explosive bolts and jettison the pusher three-blade propeller and dorsal fin to increase the chances of successfully bailing out using the pneumatic ejection seat. When fired, the seat pushed the pilot away from the aircraft with a force of 20 Gs.

 

[davebender]

Heavy bomber (by German definition) vs dive bomber. What sort of comparison is that? Different capabilities for different mission types.

 

[stona]

Apparently not since Germany had no plans to place the Do-335 into mass production during 1945.

What is mass production?
Lieferplan No.227/1 of 15th November 1944 required 4,174 Do 335s of various types to be produced by March 1946, including substantial production throughout 1945.
For example, according to the minutes of a meeting held on 24th January 1945 "series production" of the Do 335 B-6 was to start in April 1945.

Other points, from other posts.

The rear fuselage was not "packed with explosives". There were far more dangerous and vulnerable components on any 1940s war plane to worry about.

The pneumatic ejection seat worked in conjunction with the tail jettison system. Actually only a few attempts were made to use it and these were less than successful.


Cheers
Steve

 

[tomo pauk]

Both bombers required two engines and multiple crew to fly it. With those resources spent/invested, the Do-217 was able to carry more fuel and bombs, internally to boot with. Unlike Ju-88, it was also able to carry the LW's guided missiles.

BTW, English-language Wikipedia got the wing area wrong for Do-335: it was 38 m^2, not 55 m^2. Hornet was at 33.5 m^2. I mixed up the bomb bay capability - one 1100 lbs bomb was the max.

 

[davebender]

Ju-88 dive bomber could place bombs far more accurately. It also had superior aerial performance when powered by a pair of V12 engines.

Historical Do-217 was a decent heavy bomber. With Jumo 222 engines it probably would have been an outstanding heavy bomber. But that's another discussion.