Dornier Do 335 Pfeil

[Roddoss72]

Originally Posted by Randy

No combat but a French pilot reported that he saw something that he described looking like this pull away from him. Note the stubby non-original (original lost) spinner on the rear prop on the restored 102. Also, the Germans restored 102 with black spinners and props (since corrected) even though the Smithsonian (who supplied them with lots of information) documented these as being black green.

Mind-numbing trivia you can mention to your dentist while he gives you your latest root canal: The rear prop blades had to be cut down about 1.5 inches each . . . tip speeds were too high because the airflow was faster through the rear prop than the forward one.

Salutations All

I concur, the Dornier Do-335 never deployed in combat.

Regards

Roddoss72

[Wolster]

Originally Posted by McCoy

Dornier Do 335 A-1 ”Pfeil”

Manufacturer: Dornier-Werke GmbH.
Type: Twinengine fighter
Crew: 1
Length: 13,87 meters
Wingspan: 13,8 meters
Heigth: 4 meters
Weight: 7400 kg (empty)
Engine: Two Daimler-Benz DB603 G V12 fore n' aft in the airframe, pushpull configuration.
Speed: Cruising speed 665 km/h, topspeed 765 km/h
Operational range: 2050 km, 3750 km with droptanks.
Max ceiling: 11410 meters
Arnament: 1 MK103 30mm cannon fireing through the front spinner and two MG151/15 15mm machineguns in the forward engine cowling. An internal bomb bay for one 500 kg bomb and supports under the wings for droptanks or gunpods.
Other versions: A-4 reccon, A-6 tvoseated nightfighter with radar och MG151/20 instead of MG151/15 and without the internal bomb bay, A-10 & A-12 Twoseaters for training, B-1 with two additional MK108 30mm cannons placed in the wings.

The first flight with the prototype Do 335 V1 was made in october 26 '43 and the airspeed of 560 km/h was reached just by using the rear engine and folding the front propeller against the wind in order to reduce drag. Do 335 A-1 began production in the end of november ’44 and a total of 90 planes in various confiruations was built by the end of the war, 60 of those was flown and 20 of them did reach the airdivisions. One thing to remember is that Do 335 was the first airplane in history that was equiped with a serieproduction catapult chair. They had to as it was impossible to eject safely without it due to the rear prop.

Interesting point. But actually ejecting from one of these was a 5 stage process. The first stage blew the rear propellor of the plane, the second blew off the upper verticle stabiliser. The seat was then 'primed', then the canopy was ejected. Finally the pilot ejected.

This from Captain Eric Brown's biography 'Wings on my sleeve'.

He also states he heard a story that when the system was first used the pilot who had ejected was found dead with both arms ripped off. The second pilot to eject was also found dead with one arm ripped off. It turned out that when the pilot grabbed the two handles to eject the canopy and pulled back the canopy was ripped off by the wind so fast the pilot couldn't let go and lost his arms!!

[Wolster]

Originally Posted by cyberia

McCoy, I saw this aircraft featured a few weeks back on the Military Channel and the narration said it was the fastest prop driven plane of the war.

But I have learned no to trust the narration on some TV documentaries.

Was this really the case?

I believe the Supermarine Spiteful was faster at 476mph. It too never saw action but as it had it's maiden flight in 1944 I would guess it has as much claim to the title as the Do335.

[MAGNA]

A very interesting plane. Thanks Wolster. I have two 1/72nd scale models of these among a batch I was given. The two seater is one of the models. Was it a trainer or for some other purpose ?

[Whiterook]

Oooo, interesting point on it being a trainer or not...I wonder myself.

[Randy]

Both a conversion trainer and nightfighter.

[Whiterook]

Double duty...interesting!

[Pirate-Drakk]

Originally Posted by Randy

The rear prop blades had to be cut down about 1.5 inches each . . . tip speeds were too high because the airflow was faster through the rear prop than the forward one.

Here' a little side note on propeller physics to explain this comment...


As the tip speed of the propeller nears the speed of sound it stops producing thrust. "Compression" acts on the propeller just like on the wing itself (a propeller is a rotating wing). Generally to get around this problem, they add more propeller blades to reduce the diameter (and tip velocity) instead of chopping the propeller blades. It was probably an expedient to avoid designing a new 4 blade variable pitch propeller (the Do 335 had 3 bladed variable pitch propellers...) and installing it.

However, you can't just keep adding blades because the prop wash from the previous blade will disrupted the laminar flow (create turbulence) of the air and once again cause the subsequent propeller blades to lose thrust. 4 blades was the practical limit in WWII (modern turboprop planes sometimes have more then 4 blades due to superior design).

The 4 blade limit also constrains the propeller size for a given engine horse power and aircraft speed. For example, early models of the F4U Corsair had 3 blades, but when the engine horse power was significantly increased (500+ h.p.), they had to use a 4 blade prop. At some point, adding more horse power to a WWII engine is useless because the prop size limited by the size of the aircraft and the engine r.p.m. That' where twin engine planes come in.

One post WWII method around this problem of tip velocity is to use two counter rotating props on one massively powerful engine. This method has the added advantage of eliminating the torque and P-factor (has to do with the asymmetric 'angle of attack' of the propeller blades in non-level flight). However, these complicated transmissions were beyond the technology of WWII.

For all these reasons, having two inline engines with counter rotating propellers is the next best thing, and to Do 335 incorporates these propeller physics concepts into it's design. As an added bonus, the inline engine design also reduces drag compared to a two engine fighter plane like the Me-110 or P-38.

These are some of the balance factors for an aerodynamic engineer when designing aircraft and all of these factors (and much more) were taken into account in the Do 335. It was an excellent and innovative aircraft in it's time and one of my long time favorites!!!

[MAGNA]

Originally Posted by Randy

Both a conversion trainer and nightfighter.

Thanks Randy.