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Postwar Aircraft Projects / Re: C-130 V/STOL modification projects
« Last post by Archibald on Today at 11:16:32 pm »
Now that's one hell of an idea... an Hercules with four Harrier engines. the kind of "what didn't we thought about it before" idea. Although hot gas re-ingestion isues might be... interesting. Or maybe not: it is a STOL and not VTOL. No compressor, cold air.
A SHAR engine was barely ten ton thrust so four of them should be able to lift 40 tons. A Hercules is far heavier than that. So STOL makes more sense than VTOL.   
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https://www.defensenews.com/land/2018/09/17/us-army-weapons-and-munitions-tech-development-get-congressional-cash-injection/

Quote

WASHINGTON — U.S. Army weapons and munitions technology development is getting a big cash injection in the fiscal 2019 spending bill, which emerged from conference committee late Sept. 13.

Research, development, technology and evaluation dollars for weapons and munitions technology saw a $343 million boost in the appropriations bill expected to be voted on by both chambers this week. The Army had requested just $40.44 million in RDT&E funding to improve weapons and munitions, but lawmakers are providing a total $383.44 million.

Additionally, the bill adds $139.68 million to the Army’s RDT&E budget for weapons and munitions advanced technology. The Army requested just $102 million in FY19.

A large portion of the funding is targeted at the Army’s top modernization priority — Long Range Precision Fires.
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Postwar Aircraft Projects / Re: Flying Flapjacks
« Last post by Sundog on Today at 09:10:42 pm »
IIRC, the prototype had F4U props, but there was always an understanding that it would get four-bladed teetering props. I think the decision to ax the program had more to do with the obsolescence of props versus jets.

I understand that, but I mean why they didn't just fly it for just the research. Of course, in that regard, I often wondered why they didn't just fly it with the F4U props, from a research standpoint.
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Postwar Aircraft Projects / Re: Flying Flapjacks
« Last post by AeroFranz on Today at 08:25:27 pm »
IIRC, the prototype had F4U props, but there was always an understanding that it would get four-bladed teetering props. I think the decision to ax the program had more to do with the obsolescence of props versus jets.
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Postwar Aircraft Projects / Re: Flying Flapjacks
« Last post by Sundog on Today at 05:48:35 pm »
Oh, sorry for misunderstanding  ;)
The flapping of the blades might have been necessary because at high angles of attack the props are operating in a strong edgewise flow (not unlike a helicopter rotor). The advancing and retreating blades see differing inflow velocity and need to flap to balance thrust across the disc.
Maybe someone else has a better explanation?

I just came across this interesting video of Jack Reeder, longtime engineer and test pilot at Langley
at 48:30, he says there was little practical improvement with turning the props against the direction of the vortices. He also talks about the need to provide flapping motion for the propellers.
https://www.youtube.com/watch?v=HRZu78WozBo&feature=youtu.be

My understanding is that the problems with the flapping propellers is why the XF5U-1 was never flown.
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Postwar Aircraft Projects / Re: Northrop Grumman Low Cost Fighter (?)
« Last post by Sundog on Today at 05:47:11 pm »
I recall a notable test pilot's book referenced a "YF-24" among the list of aircraft he had flown and many speculated it could be related to that Boeing "Model 24". I've no idea how likely that is though. Why would they keep it classified?

Because if such an aircraft has flown it probably incorporates some technology that they don't want made public. If you show me what my enemies are up to, I can plan a response. If I know my enemies are up to something, but I don't know precisely what it is, it is much more difficult to formulate a specific response to the threat. The element of surprise in combat is still one of the greatest assets one may possess.
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Interesting similarities between those Boeing and Northrop designs. I suppose they both might have their origins in the F-23 design considering Boeing's merger with McDonnell Douglas.

Did the USAF get to a point where they defined which specifications they wanted MRF to meet?

I recall a notable test pilot's book referenced a "YF-24" among the list of aircraft he had flown and many speculated it could be related to that Boeing "Model 24". I've no idea how likely that is though. Why would they keep it classified?
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Postwar Aircraft Projects / Re: Flying Flapjacks
« Last post by AeroFranz on Today at 01:58:36 pm »
Oh, sorry for misunderstanding  ;)
The flapping of the blades might have been necessary because at high angles of attack the props are operating in a strong edgewise flow (not unlike a helicopter rotor). The advancing and retreating blades see differing inflow velocity and need to flap to balance thrust across the disc.
Maybe someone else has a better explanation?

I just came across this interesting video of Jack Reeder, longtime engineer and test pilot at Langley
at 48:30, he says there was little practical improvement with turning the props against the direction of the vortices. He also talks about the need to provide flapping motion for the propellers.
https://www.youtube.com/watch?v=HRZu78WozBo&feature=youtu.be
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Postwar Aircraft Projects / Re: C-130 V/STOL modification projects
« Last post by Apophenia on Today at 01:54:48 pm »
Very nice Stephan!

Evan: Bill Norton's book is available on Amazon ... but for silly money  :P  https://www.amazon.com/gp/product/1563475766/ref=dbs_a_def_rwt_bibl_vppi_i6
Some pages are available on Google Books.

AW.681 . . . is that you ? ...

 ;D ;D
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Postwar Aircraft Projects / Re: C-130 V/STOL modification projects
« Last post by robunos on Today at 01:52:58 pm »
AW.681 . . . is that you ?     ;D   ::)


cheers,
           Robin.
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