Dornier Do 335 Pfeil

[timshatz]

The Do-335 was the fastest piston engine aircraft during the spring of 1945. It also had superior climb, dive and acceleration plus massive firepower. Why would you throw away your speed advantage to engage in a low speed dog fight?

Not by choice, that is for sure. But you don't always dictate the situation.

Look at the Me262. All the same things could be said about it. But sometimes it got stuck in a dogfight where the advantages were with the piston engined fighters. Not by choice or tactical design, but it happens.

Good to have a trick up the sleeve for those situations where your out of airspeed and altitude.

 

[Messy1]

Great post, lots of info and great pictures. Thanks!

 

[davebender]

Once the strategic situation has deteriorated to the point where the enemy maintain round the clock CAP over your airfields it's all over but the crying. Not even the modern day F-22 could turn the tide under those circumstances. That's the no-win situation Germany was in during the spring of 1945.

Introduce the Do-335 into operational serve a year earlier and the picture changes completely. With secure airfields to operate from the Do-335 would give Allied bomber formations a very rough time. Perhaps more so then the Me-262 as the Do-335 had greater endurance and fewer teething problems.

 

[davparlr]

The Do-335 was the fastest piston engine aircraft during the spring of 1945. It also had superior climb, dive and acceleration plus massive firepower. Why would you throw away your speed advantage to engage in a low speed dog fight?

Its amazing how many "fasted piston engine aircraft" there are. It was already obsolete due to jets and other allied aircraft such as the P-51H which would fly circles around it. In addition it had been outclassed a year earlier by the XP-72 which was faster (alas the P-47J has a claim for the fastest piston powered aircraft), had a better rate of climb and a higher ceiling, which had been cancelled due to lack of need and the jet. I think the performance you are talking about include engines never used and therefore, unsubstantiated. Propeller driven aircraft was at its limits and technology would just not push it much further.

 

[zoomar]

Its amazing how many "fasted piston engine aircraft" there are. It was already obsolete due to jets and other allied aircraft such as the P-51H which would fly circles around it. In addition it had been outclassed a year earlier by the XP-72 which was faster (alas the P-47J has a claim for the fastest piston powered aircraft), had a better rate of climb and a higher ceiling, which had been cancelled due to lack of need and the jet. I think the performance you are talking about include engines never used and therefore, unsubstantiated. Propeller driven aircraft was at its limits and technology would just not push it much further.

Also, the Spiteful, MB-5, and Hawker Fury would have matched or exceeded the Do-335 in speed. I can also agree with your observation that a lot of what we "know" about the Do-335's likely operational capability (just like what we know about the He-162, Go-229 and other late war German prototypes) is based on design specs, a few surviving test pilot reports, a few chance encounters with allied pilots like Clostermann who may or may not have actually saw what they thought they saw (consider the occasional "He-113"s encountered by USAAF bombers and fighters in 1943-44), and the recollection of people involved in these programs. Of all these sources, I'd put combat pilot encounters and memoirs of test pilots and designers at the bottom of the reliability list.

But remember, the Do-335 was not intended to mix it up with single engined fighters half its size. It was designed as a fast twin engined intruder and (only secondarily) a bomber zerstorer, and at that role, it would have been a remarkable airplane if it was in squadron service by early 1944, at least as fast as and quite a bit more versatile than the Ar-234. Speculating further into a hypothetical future, there is no reason to believe it would be "made obsolete" by the fact that F-80s, Meteors, Vampires or even F-86s and Mig-15s were around, any more than the F-82, Douglas B-26, and Skyraider were made obsolete because they shared the sky with jets 100-200 mph faster than they were.

 

[timshatz]

Probably would've had a second life as a Night Interceptor/Intruder even after it's time in the day had passed. It was a remarkable plane, once they got the cooling problem of the after engine ironed out.

We were kicking it around in a previous thread and one of the indeas that came up was a long range, maritime, heavy fighter. Could've doubled as a scout bird too. Have two of them take off from Brittany with several long range tanks on the underside of the wings, use one engine for patrol instead of two, and set the controls with long range fuel efficiency and there is litterally no end to the places it could show up around the British Isles.

No end to the trouble they could cause.

 

[Nikademus]

Also, the Spiteful,

But remember, the Do-335 was not intended to mix it up with single engined fighters half its size. It was designed as a fast twin engined intruder and (only secondarily) a bomber zerstorer, and at that role, it would have been a remarkable airplane if it was in squadron service by early 1944, at least as fast as and quite a bit more versatile than the Ar-234.

How would you compare vs. the P-38J-25-LO/P-38L, often considered the ultimate heavy fighter.

 

[riacrato]

It's true Do 335 was first and foremost an intruder, only pushed to become a fighter by Hitler. But then, I think Ar 234 has better speed loaded with 1000 kg, better speed on sealevel, can take up to 1500-2000 kg if necessary, has much better view to the ground, was almost instantly successful (much less quirks to work out) and is likely even cheaper.

 

[VG-33]

The Do-335 is one of those great and innovative ideas that almost certainly would have been copied by other piston-engined warplanes had jets not come along and ruined everything. It had all the advantages of two engines providing centerline thrust without the drag and extra weight of a twin boom design or the complications of pairing the engines to drive a single set of propellors (contra-rotaing) as a tractor (Ki-64) or pusher (B-43 Mixmaster).

Great and innovative? You seem to discover the America but it was well known since 1912 with concrete Breguet experiences in France and Sikorsky "Grand" in Russia that propellers on tandem mounted engines had a much lower output than parallel ones. The first propeller is always perturbating the aft one with turbulences. Moreover the path due to accelerated flow is difficult to calculate and then to adapt at all flight regimes. Especially near transsonic speed as Do-335 did.

So the best solution is to adapt slow and contra-rotating synchronised big propellers with evolutive profiles as Tu-95 did, in order to avoid near sound speeds.

Nothing to copy about the Do-335, look at De Havilland DH 103 Hornet. The extra engine pods are more than compensated by better propellers outputs, no?
Just a solution between the others, nothing advanced or miraculous...

 

[Shortround6]

Tandem engines were so common from WW I until the thirties that putting 4 engines on the leading of a wing was considered the rarity.

Of course these tandem engine nacelles were much closer coupled than the propellers on the Do 335, so perhaps the airflow had a bit more time/distance to straighten out than on there older designs.

 

[MikeGazdik]

It seems to me the Do-335 and the Grumman F7F are very good to pit against each other in what thier potential may have been.

 

[davebender]

The F7F is about 50% larger and completely different in layout. Other then being late war aircraft I don't see much in common.

 

[Shortround6]

The F7F is about 50% larger and completely different in layout. Other then being late war aircraft I don't see much in common.

Not sure how you figure the F7F was 50% larger.

They seem to be with about a foot of each other in length, F7F has about 6ft more wingspan and about 10% more wing area.
The 11,484lb empty weight in wiki for the Do 335 is a joke. NO plane with a pair of 2,000lb engines, props to suit, radiators&oil coolers, cowlings, etc is going to have an empty weight of only 11,484lbs. Two other sources give an empty weight of over 16,000lbs which puts it within a few hundred pounds of the F7F.

 

[VG-33]

Tandem engines were so common from WW I until the thirties that putting 4 engines on the leading of a wing was considered the rarity.

The "rarity" improved the Sikorsky speed in 15 km/h (20%), 25% height and improved 35% TO distance. But the Grand had room for four 100 HP Arguses on it's wings.

For the other planes, tandem engines were used for structural reasons, in order to save size, and so weight

Of course these tandem engine nacelles were much closer coupled than the propellers on the Do 335, so perhaps the airflow had a bit more time/distance to straighten out than on there older designs.

It's a bit true, but i'm sure that at 10 m distance after a 2150 hp and 3.5m propeller the flow in the current tube is still far from being smooth and laminar.

It would be curious to have the prop's RPM to verify if blade tips were supersonic or not?

Regards

 

[MikeGazdik]

The F7F is about 50% larger and completely different in layout. Other then being late war aircraft I don't see much in common.

I agree with the completely different layout, which makes the comparison all the more interesting. A traditional twin engine aircraft vs the non-traditional.

I would love to see these two brutes slug it out in a heavy weight fight! Throw in the De Havilland Hornet too !!

 

[timshatz]

It's true Do 335 was first and foremost an intruder, only pushed to become a fighter by Hitler. But then, I think Ar 234 has better speed loaded with 1000 kg, better speed on sealevel, can take up to 1500-2000 kg if necessary, has much better view to the ground, was almost instantly successful (much less quirks to work out) and is likely even cheaper.

I'd be leery of taking the Ar 234 far out to sea with those engines. With them conking out every 10-25 hours, odds are one of them would blow during a long range patrol.

Also, it's more of a bomber than a fighter. As a bomber intruder, it has pretty good potential. As you note, the payload and speed will make it something like the Mosquito. Almost impossible to intercept during the day and even worse at night.

Still, those engines are a problem.

 

[zoomar]

Great and innovative? You seem to discover the America but it was well known since 1912 with concrete Breguet experiences in France and Sikorsky "Grand" in Russia that propellers on tandem mounted engines had a much lower output than parallel ones. The first propeller is always perturbating the aft one with turbulences. Moreover the path due to accelerated flow is difficult to calculate and then to adapt at all flight regimes. Especially near transsonic speed as Do-335 did.

So the best solution is to adapt slow and contra-rotating synchronised big propellers with evolutive profiles as Tu-95 did, in order to avoid near sound speeds.

Nothing to copy about the Do-335, look at De Havilland DH 103 Hornet. The extra engine pods are more than compensated by better propellers outputs, no?
Just a solution between the others, nothing advanced or miraculous...

Unless I am wrong the examples you have mentioned are all with engines mounted in relatively short nacelles, either on the wings, or in a few other cases besides those you mention, in short fuselage pods between twin booms. To my knowledge, the layout used by the Do-335 was virtually unique in aviation. Some planes had centerline pusher props placed aft of the tail assemblage, and many (of course) had centerline tractors, but to my knowledge, only the Do-335 combined the two concepts. It is thus highly radical and innovative. Was it great? Who knows? As I mentioned in another post, we really have no way of objectively evaluating the real life performance and operational suitability of many late war German design concepts because they saw so little service, were often affected by declining production standards, are still the subject of legitimate debate, and (in the case of the Do-335, at least) were not pursued after the advent of jets. However, based on most figures quoted in literature, the Do-335 had great acceleration, and could reach speeds in the 450-470mph range. This would appear to make its performance at least equivalent to the DH Hornet or F7F. My guess (purely subjective, of course) is that, if somehow the tandem centerline pursher pull concept of the Do-335 was introduced 4-5 years earlier, you would have seen other aircraft designed and built which copied the basic concept.

 

[timshatz]

I agree with the completely different layout, which makes the comparison all the more interesting. A traditional twin engine aircraft vs the non-traditional.

I would love to see these two brutes slug it out in a heavy weight fight! Throw in the De Havilland Hornet too !!

Pretty cool idea. All were heavily armed, very fast and probably had excellent range. My inclination would be to give the Do335 the edge in manuver but I'm not sure. If they all had hydraulic assist, it might be a moot point.

The Arrow is probably less draggy but not sure about that either.

In all, they are three very closely matched aircraft. Good call Mike.

 

[bobbysocks]

happened onto this..kinda cool


View: https://www.youtube.com/watch?v=xFf4zKtmaMM

 

[timshatz]

happened onto this..kinda cool


View: https://www.youtube.com/watch?v=xFf4zKtmaMM

It is kinda cool. Wonder if he has problems with cooling.