Exhaust Thrust ????

[Crumpp]

To further illustrate the point, I have included the Lycoming O-360 Operators Manual.

 

The connection to the German engines is the fact is it not unusual for a manufacturer to make a single engine and tune that basic engine for different applications. Junkers certainly did this for the Jumo 213 series.

 

The engines will created different amounts of power based on that specific application.

 

In the case of the O-360 we see a 16% power variation out of the same basic engine. The Power variation we are seeing in the Jumo 213 charts is ~4.7%.

[Crumpp]

Just compare the graphs to the Jumo 213a.

http://www.forum.lockon.ru/attachment.php?attachmentid=88144&d=1379528179

 

Excellent agreement....but is it a fighter variant engine?

[TAGERT]

During the restoration of White 1, we did not start out with a good core engine to rebuild.

That's cool!

 

You must have some cool pictures of yourself standing next to the engine, or some cool pictures of you working on the plane that you could share with us!

 

I love those restoration shops, I use to ride my bike down to Chino airport when I was a kid and watch them restore the WWII planes, I wish we had the phone cameras we have today back than! All I have now is memories! ;)

[Crumpp]

Speaking of that, I am now really looking forward to the release of the Spitfire in DCS to see how exhaust thrust will be added there.

 

Here is the Mark I with NACA ejector stacks.

[Yo-Yo]

Excellent agreement....but is it a fighter variant engine?

 

Yes, and the reason we used the factory engine settings was that 1900 ps , 3250 rpm was a power rating with increased filling without mw50. There is at least one report where this setting is tested. So, this graph represent not standard filling settings.

[Kurfürst]

Here is the Mark I with NACA ejector stacks.

 

I wonder how much of that 6 mph speed increase with the NACA style exhaust compared to the original stubs by Supermarine was due to simply not having a large chunk of metal sticking out left and right of the engine. :lol:

[Crumpp]

Yes, and the reason we used the factory engine settings was that 1900 ps , 3250 rpm was a power rating with increased filling without mw50. There is at least one report where this setting is tested. So, this graph represent not standard filling settings.

 

The 1900PS based engine.....

 

:doh:

 

Got it. Thanks again Yo-Yo!

[Crumpp]

I wonder how much of that 6 mph speed increase with the NACA style exhaust compared to the original stubs by Supermarine was due to simply not having a large chunk of metal sticking out left and right of the engine.

 

Removing large chunks of drag producing metal sticking out on both sides will help improve speed!

 

Honestly, I am not sure what they were thinking with the original exhaust design outside of noise abatement.

[Friedrich-4B]

Here is a 1943 NACA report on exhaust back pressures:

[Crumpp]

Here is a 1943 NACA report on exhaust back pressures:

 

Unless your building a header system and using the low pressure to increase the high pressure velocity...

 

Back pressure is not a good thing to have in an exhaust system.

 

Was that the thinking behind the huge exhaust system on Spitfire Mk I? Kind of short to achieve that effect weren't they?

[Kurfürst]

Either the exhaust had back pressure problems (they seem to have encountered this a couple of times with the Merlin), or perhaps they wanted to have minimal glare for night flying, as this was IIRC a compain with the proto-Spit.

 

I would say that someone at Supermarine had a bad case of exhaust stub fetish, as they ended up with a perfectly ordinary one fitted in the end.

[Kodoss]

The Bundesarchiv has a flighttest of the Fw 190 D-9 (March 1945).

RL36/103 - Focke-Wulf Fw 190 D-9 mit Jumo 213 A, Flugleistungen.- Teilbericht 2, Erprobungs-Nr. 9003, Bearbeiter: Delz

 

There was also a paper about exhaust thrust in the archiv, trying to find that now.

[Kodoss]

Fond a report of Junkers and DB exhaust thrust nozzles from 1939.

RL36/186 - Junkers- und Daimler-Benz Abgasrückstoßdüsen.-Teilbericht-Nr. 1, Erprobungs-Nr. 2481

 

2 other reports about exhaust devices

RL 3/1156 - GL/C - E 3 VI.- Abgasanlagen in Flugzeugen (1941-1943)

RL 3/1157 - Fortentwicklung von Abgasanlagen an Flugzeugmotoren (1941-1943)

[Crumpp]

That would be great Kodoss!

[Friedrich-4B]

I would say that someone at Supermarine had a bad case of exhaust stub fetish, as they ended up with a perfectly ordinary one fitted in the end.

 

Not that Supermarine were responsible for the design of the exhaust stubs :smilewink:

 

 

But, somehow, the British muddled through, in spite of their poor design philosophies and slow, badly designed fighters. :music_whistling:

[NineLine]

Either the exhaust had back pressure problems (they seem to have encountered this a couple of times with the Merlin), or perhaps they wanted to have minimal glare for night flying, as this was IIRC a compain with the proto-Spit.

 

I would say that someone at Supermarine had a bad case of exhaust stub fetish, as they ended up with a perfectly ordinary one fitted in the end.

 

 

Well I think most engineering back then was done sort of by the seat of their pants (especially in the thick of the war), I am sure there was a good many things that didnt work out well by both Allies and Axis :)

[Crumpp]

Well I think most engineering back then was done sort of by the seat of their pants (especially in the thick of the war), I am sure there was a good many things that didnt work out well by both Allies and Axis

 

Harnessing exhaust thrust was one of those areas of aircraft engineering discipline that came into its own during World War II much like stability and control engineering.

 

Like stability and control engineering, the levels of technical savvy were not always equal.

 

The first real theoretical investigation appears to be Hermann Oestrich Prospects for Jet Propulsion of Airplane with Special Reference to Exhaust Gases.

 

That was in 1932. When the war started, it appears the idea appeared much more than theoretical and everyone started investigating the most efficient way to harness it.

 

But, somehow, the British muddled through, in spite of their poor design philosophies and slow, badly designed fighters.

 

The British put up some very good designs and were a leading nation in subsonic aerodynamics. Gates can be considered one of the founding fathers of modern stability and control engineering and his stick force per G criteria is still used today.

 

That does not mean the establishment at the RAE welcomed outside ideas with open arms.

Exhaust stacks for individual cylinder exhaust-Jet-Propulsion system.pdf

Exhaust thrust thru experimentation.pdf

[TAGERT]

During the restoration of White 1, we did not start out with a good core engine to rebuild. We proceeded in the beginning of the project with the understanding we would have to resurrect the BMW801D2.

Crump, any chance of you sharing some pictures of you standing next to the BMW801D2 engine or working on the White 1 Fw190?

 

Would love to see some of those pictures!! :pilotfly:

[Friedrich-4B]

Crump, any chance of you sharing some pictures of you standing next to the BMW801D2 engine or working on the White 1 Fw190?

 

Would love to see some of those pictures!! :pilotfly:

 

There don't seem to be many images of White 1 on the internet, so it would be good to see some photos of the project progressing in its early stages.

 

AFAIK, the project is still underway and now under the Collings Foundation after the White 1 Foundation folded

 

http://www.warbirdsnews.com/warbirds-news/focke-wulf-fw-190f-8-restoration-underway.html

[Crumpp]

AFAIK, the project is still underway and now under the Collings Foundation after the White 1 Foundation folded

 

http://www.warbirdsnews.com/warbirds...-underway.html

 

Yes it was sold to the Collings Foundation. If you wanted pictures of the early project, you should have joined and contributed.

 

Thanks!

 

:thumbup:

[Friedrich-4B]

Yes it was sold to the Collings Foundation. If you wanted pictures of the early project, you should have joined and contributed.

 

Thanks!

 

:thumbup:

 

What a shame; looks like the only people who will ever see photos of White 1 are ex- Foundation members. :no_sad:

 

Ah well, here's one at least, dated August 2010 - part of a portfolio on Wikipedia:

 

 

Actually, there are several photos from 2010, although the photo of the purported engine definitely isn't a BMW 801

 

https://commons.wikimedia.org/wiki/Category:Focke-Wulf_Fw_190_museum_aircraft

Edited March 15, 2015 by Friedrich-4/B

[TAGERT]

Yes it was sold to the Collings Foundation. If you wanted pictures of the early project, you should have joined and contributed.

So, just to be clear, no pictures exist of you standing next to the engine and/or working on White 1?

[NineLine]

So, just to be clear, no pictures exist of you standing next to the engine and/or working on White 1?

 

I sure hope this isnt trolling.... I mean I hope you just really want a picture of Crumpp for your desktop right... either way, knock it off... stay on topic, yadda yadda...

[TAGERT]

I sure hope this isnt trolling.... I mean I hope you just really want a picture of Crumpp for your desktop right... either way, knock it off... stay on topic, yadda yadda...

Yes, I really want to see some detailed pictures of White 1! Based on Crump's post, I get the impression he was an integral part of the restoration! So, I would think he has some pretty cool pics showing the restoration.

[NineLine]

Yes, I really want to see some detailed pictures of White 1! Based on Crump's post, I get the impression he was an integral part of the restoration! So, I would think he has some pretty cool pics showing the restoration.

 

Fine, send him a PM, this thread is about exhaust thrust, not Crumpp's photo collection.