Dornier DO 31

[althenick]

An interesting way to use Peggy Engines ....


Dornier Do 31 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Dornier_Do_31)

I wonder what this Aircraft could have done with the final variant of the Pegusus Engine to power it.

What do you Engineering types think?

[LowObservable]

My guess would be "carry a Smart car 150 nm and deafen everyone for two miles around".

[SammySu]

Or with 4 x 23500lb podded Pegasus rather than 2 x 15500lb versions and 8 4400lb lift jets, much more thrust, much less drag which I think was the technical problem first time around.
Would also benefit from modern FCS technology for simple transitions as per the VAAC Harrier and subsequent F35 control laws.
Wouldn't be Stage iii compliant though :D

[Davef68]

Or the Fairey Rotodyne witrh Pegasus rather than Ellands....

[JFZ90]

i assume another issue was that a single pegasus engine failure was presumably catastrophic in several parts of the flight envelope. just about tolerable with a harrier, but not normally ok with something that could carry pax. i guess the 2 front seats were martin baker?

[BEagle]

I remember seeing (and certainly hearing!) the Do-31 at the 1969 Paris Air Show. That was the 10-engined version which was capable of VTOL flight and it demonstrated its capabilities most impressively!

Visit the Dornier museum at Friedrichshafen and you can see the Do-31, together with many other rare Dornier designs.

But not the Do-217 or Do-335.....:\

[Chugalug2]

This was the one that the MRT Force was waiting for in the 60's. Waiting and waiting...
Armstrong Whitworth AW.681 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/AW.681)

[barnstormer1968]

While we are looking back at old VTOL contenders, or equipping old models with new engines, could we poke the French to making the 'Rafale son of Balzac' (sp)

It was fast and looked good in its original form IMHO

[John Farley]

Sorry chaps the notion that old jet VSTOL contenders failed just because they were short of thrust is too simple. They all had problems with one or other of these things (sometimes both).

1 There was no provision for keeping the hot efflux out of the intakes.

2 The lift systems left little room for anything else.

Putting more thrust in to such designs would not have helped and with some aircraft (D031 for one example) would have made matters worse.

[GreenKnight121]

Or the Breguet Br.1030.
http://www.secretprojects.co.uk/forum/index.php/topic,10772.0/all.html

Planned test aircraft:
http://i22.photobucket.com/albums/b336/Bager1968/Aircraft/developmental%20aircraft/Br-1030_zpsa29b9132.gif (http://s22.photobucket.com/user/Bager1968/media/Aircraft/developmental%20aircraft/Br-1030_zpsa29b9132.gif.html)

Intended transport development:
http://i22.photobucket.com/albums/b336/Bager1968/Aircraft/developmental%20aircraft/Br-4-liftfans_zps61b15d3a.gif (http://s22.photobucket.com/user/Bager1968/media/Aircraft/developmental%20aircraft/Br-4-liftfans_zps61b15d3a.gif.html)
http://i22.photobucket.com/albums/b336/Bager1968/Aircraft/developmental%20aircraft/Breguet1030intendeddevelopment_zps78f38844.jpg (http://s22.photobucket.com/user/Bager1968/media/Aircraft/developmental%20aircraft/Breguet1030intendeddevelopment_zps78f38844.jpg.html)

[Rigex]

In addition to Beagles find, there's another (which you can walk through) :) at the Deutsches Museum collection at Oberschleißheim near Munich.

Also look here:

Deutsches Museum: Oberschleissheim Airfield, Information (http://www.deutsches-museum.de/en/flugwerft/information/)

[sisemen]

Just another one of those crazy ideas that abounded in the aviation world post-war until the design teams started to settle down.

[Chugalug2]

I don't think they were crazy, sisemen, simply trying to satisfy their prospective customers demands. Their customers anticipated a war in which the first targets would be every single runway, military and civil. Bristol Engines and Hawkers came up with a solution, but that created its own re-supply and support problems. These various transport projects sought to satisfy that demand, though I grant with varying degrees of reality.
Did you know that the TSR2 was to be VTOL enabled with a Shorts VTOL airborne aircraft carrier? Now that was crazy!

[Engines]

John,

Nice post as ever.

If any visitors would like to find out more about the various V/STOL ideas tried, a good place to start can be found at Vertical and/or Short Take-Off and Landing (V/STOL) (http://www.vstol.org/), where you can find the quite wonderful 'V/STOL Wheel'. It shows no less than 45 ways of trying to do what Hawkers achieved with the Harrier.

If nothing else, it should give anyone a better appreciation of just how good those designers, engineers and pilots at Kingston (and Bristol) were.

Best Regards as ever

Engines

[dead_pan]

'V/STOL Wheel'

Excellent, although have they missed a few off e.g. stop-rotors?

Didn't know the Rotodyne had tip jets. A bit before my time.

[sisemen]

I guess what I meant by 'crazy' was the 'pushing the envelope' think tank mood which was exploring the options until the inevitable dead end hit them. You only have to look at the list of weird and wonderful projects and prototypes that abounded in the latter stages of WW2 and the immediate post-war period. Once the dead-ends had been sifted and sorted it kind of settled down into a conventional design paradigm with the occasional "outside the square" advance.

[althenick]

Thanks for the link Engines. I never realized just how many VTOL Designs were out there - and also how many of them relied upon Rolls Royce to power them! I'm a big fan (Sorry for the pun) of Not reinventing the wheel and as such I think Rotordyne should be revisited. Whould an updated design of this Aircraft really need Tip - jets?

Al

[dead_pan]

According to Flight a week or two ago, the departing head of Eurocopter predicted a rennaisance in helicopter travel, citing new, faster & lower operating cost developments based on their X3 design, whose lineage you can trace back to the Rotodyne. As always I suppose it was an idea ahead of its time.

[Engines]

Athelnick,

In my view, yes, an updated Rotodyne would still need tip jets, because that gave it the very low weight, zero torque rotor propulsion system it needed. No gearboxes, no transmission shafts - just hot gas ducts from the two turboprops in the wings.

That said, Fairey had big problems with the stainless steel ducts, which had to double as rotor blade spars. The other big issue was noise from the tip jets - but they were a long way down the track of a silencer design.

I actually watched the aircraft land at Battersea Heliport - and it was VERY loud.

Best Regards as ever

Engines

[BEagle]

I'm a big fan (Sorry for the pun) of Not reinventing the wheel and as such I think Rotordyne should be revisited. Whould an updated design of this Aircraft really need Tip - jets?

JF and I disagree (politely) about the Rotodyne, which is often accused of having been 'too noisy'. The first prototype was certainly pretty noisy, but huge advances were made throughout the latter days of the project and considerable noise reduction had been achieved. When it flew to Battersea Heliport, there were NO noise complaints, just a few curious enquiries as to what was going on.

The Rotodyne did not need massive helicopter transmission systems and only operated in tip-jet mode for vertical take-off or landing. For the rest of the flight, the rotor operated in free-wheeling autogyro mode, with additional lift from the stub wings which housed the main engines - another source of programme delay, courtesy of Napiers.

Just as the production version's specification was being signed-off, the much-underrated Rotodyne died under a Conservative government several years before Wilson and his fellow-travellers killed TSR2, HS681 and P1154. A pity; had it been developed than the Rotodyne could perhaps have been a pioneering inter-city airliner and military transport

Nowadays you'd have to find a 'killer application' for the Rotodyne to be resurrected and there simply doesn't seem to be one.

It was certainly more viable than the Do-31.

[JFZ90]

interesting on wiki - clearly at 113db it was insanely loud, but they seemed on track to hit 95db at 200ft - which is massively quieter.

at these lower levels, was it still to be a dead duck?

PS is it right that a single pegasus engine failure (not unheard of in the harrier), would have been catastrophic in any non-conventional flight modes of the Do-31, and maybe in any regime? Did it ever fly with someone not in an ejector seat?

[dead_pan]

I think Rotordyne should be revisited

Hmm - maybe. I suppose whoever's in possession of the design could license it to an enterprising Chinese aerospace company to see if they could make anything of it.

[John Farley]

dead_ pan

To get on the wheel you had to fly (or at least try).

[dead_pan]

Nowadays you'd have to find a 'killer application' for the Rotodyne to be resurrected and there simply doesn't seem to be one.

Re the killer app, have a look for the Flight article to which I referred. The Eurocopter head was talking about large capacity VTOL flying short-haul routes as an alternative to building additional runway capacity, with all its associated costs and timeframes.

JF - you've lost me there.

[BEagle]

JF - you've lost me there.

According to the website:

The V/STOL Wheel is a graphic diagram of all 45 types of vertical and/or short take-off and landing (V/STOL) aircraft that had been built and tested through 1996. It was updated from the McDonnell Douglas Wheel of the 1960s for the Joint Strike Fighter (JSF) Program Office.

So stillborn projects such as the Br.1030 do not appear on the Wheel.

[dead_pan]

Ahh okay.

I suppose that Heath-Robinson-esque contraption recently built and flown by the Australian husband-and-wife team doesn't really count, as it is not an 'official' project. According to the NASA Dryden web site, the X-wing did fly but without the rotor attached.

[Kerosene Kraut]

The Do-31? I see it as the rich man's Osprey.

[ORAC]

1 There was no provision for keeping the hot efflux out of the intakes.

kZcpg70Ewbw

[Foxxster]

New video.

https://m.youtube.com/watch?v=FM-OOo4Sw-o

[Martin the Martian]

It's actually quite a good looking aircraft, with shades of Flash Gordon's War Rocket Ajax in its appearance (google it). The flexing of the wings on landing was impressive, and makes you wonder at what point the engine pods would come off.

The question I have is with regard to later Pegasus variants, which could have substituted the RB162 batteries and turned the Do 31 into a four Pegasus design, making it even more useful by not having to cart around the batteries when they were not doing anything useful. Four Mk.103s would have given over 80,000lb of thrust, as opposed to the Pegasus 5/RB162 combination as used, which gave a combined 66,000lb.

[622]

Buried in that original link was this...kind of looks familiar!

https://en.wikipedia.org/wiki/VFW_VAK_191B

[DirtyProp]

What about the DO 29? I always thought it was great.

https://en.wikipedia.org/wiki/Dornier_Do_29

[Commando Cody]

It's actually quite a good looking aircraft, with shades of Flash Gordon's War Rocket Ajax in its appearance (google it). The flexing of the wings on landing was impressive, and makes you wonder at what point the engine pods would come off.

The question I have is with regard to later Pegasus variants, which could have substituted the RB162 batteries and turned the Do 31 into a four Pegasus design, making it even more useful by not having to cart around the batteries when they were not doing anything useful. Four Mk.103s would have given over 80,000lb of thrust, as opposed to the Pegasus 5/RB162 combination as used, which gave a combined 66,000lb.

Couple o' issues here.

First, this would be horribly inefficient compared to alternatives. Compromises acceptable in a fighter/attack vehicle won't do for a transport, which is what Do-31 kind of was. If FVL-Heavy or Ultra comes about, a large Tilt-Rotor would meet the cargo craft need much easier.

Second, any engine power loss would result in an instant and uncontrollable roll unless there was a very fast acting system to reduce power on the other side which would allow you to crash inn a level attitude instead. On VTOL jets that have more than one lift source (Yak-38, F-35B, etc.) if one of the lift sources goes down, the aircraft autoejects you almost instantly. Not a viable option in this type of craft.