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Yes Kaiserbill,but sorry no more Info.
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Military / Re: General Atomics Electromagnetic Rail Gun
« Last post by seruriermarshal on Today at 04:53:54 pm »
I remeber they used it on a M109 last year .
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AeroFranz wrote
Quote
I was reading in "Radical wings" that apparently the V-173 was tested in a wind tunnel with the props rotating in both directions (tips going up outboard/ tips going down) and they found very small differences in lift and drag. They did measure a much larger change in longitudinal stability. this must be somewhere on an NACA report on the NTRS, it would be interesting to dig that up and read the actual details.

I found images of that model, but the two-bladed props were fitted to spin outboard, as if to counter wing-tip vortices. I'd like to see more of the studies with them spinning the opposite direction -or to find images of such props fitted.
 This seems to confirm that the V-173 did not need the huge flapping counter-props for it's low speed landings, nor to be effective in low-A cruise. The vortices are not present in cruise, only in low speed very high "A" flight.

(edit)
I just reserved/requested a copy of that to my local library.

https://www.amazon.com/Radical-Wings-Wind-Tunnels-Advanced/dp/1580071163
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Postwar Aircraft Projects / Re: SR-72?
« Last post by marauder2048 on Today at 03:03:31 pm »
Quote
So yeah, very much nudge-nudge-wink-wink-saynomore there.

Odd given that Aerojet already confirmed that it's Aerojet propulsion on the plane.
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The low-aspect ratio plane, like the Boeing 396, did not need to props counter-spinning over the wingtips. The Arup plane was what celled Zimmerman's concept for a VTOL twin-rotor craft; He worked for NACA and was on the team that saw the Arup S-2 fly and it made slow landings, and flew 97+kts on 37 horsepower. It did not exhibit any supposed detrimental excessive drag due to wing-tip vortices at cruise low "A" flight. It was sleek and quick, as an all-wing.
It was after that, when he won a context with a low-aspect-ratio twin-rotor hovering craft. His early patents show plainly that's what the twin props were for.

Look at the NASA Studies of the Wainfan Facetmobile. At low speed very high A flight, you want to huge wing-tip vortices, to keep the flow from the leading edge over the top of the wing from separating, to allow the low-speed flight. You wouldn't want to counter it if you could. As it turn out, The V-173 didn't. It still made the super-slow flight, despite the counter-props.

It seems to be a myth that all low-aspect ration planes suffer high drag due to those supposed vortices. They're not present at cruise.
The huge giggle-factor inducing props were an un-necessary complication, and the gearing system for them doomed the XF5U to being impossible.
If the Navy had contracted Boeing to build the 396, as an honest study of the Arup planform, things might have been different.,
A jet would have done fine.

Why the Navy accepted that the huge silly flappy twin props over the wing-tips were necessary, we can't know.

We might call the V-173 "Zimmerman's folly" or how the Navy threw away the Boeing low aspect-ratio fighter.
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The Bar / Re: Needle in a haystack, giant booster edition
« Last post by George Allegrezza on Today at 02:25:54 pm »
Thank you Martin!
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Seems $373,993,951 is not enough to get a Sequel,

$374 million is a lot of money, but not much of a return on a $135M investment... especially with the skewed national results.

I'm still waiting for that sequel to "John Carter." I think I'll be waiting for a while.
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Postwar Aircraft Projects / Re: SR-72?
« Last post by CJGibson on Today at 12:58:36 pm »
Just up the road from Air Products at Pueblo.




Chris
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Aerospace / Re: Germany seeks pricing for 41 CH-53K King Stallions
« Last post by marauder2048 on Today at 12:50:46 pm »
I've seen it called a "Spähpanzer" so if you use the crude English translation of "panzer" you get a tank!
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