Vampire vs Me 262

[FLYBOYJ]

Originally Posted by kool kitty89

For the re-engined Me 262, I was thinking for experimental purposes for testing the airframe. Plus for safety reasons for the unreliable 004's and small amount of spares.

And on a swept wing P-80: Lockheed F-80E

But then I think the next step was....

Lockheed XF-90

[kool kitty89]

Nice design, a bit overbuilt (with very thick skin and heavy duty aluminum forgings) though making it too heavy. The engines could have been a bit more powerful too. It had J34's with ~4,200 lbf AB, while there were varients of the J34 which could put out 4,800+ lbf AB (or 4,900 lbf like the X-3's), which the competing XF-88 did use. (which was lighter to boot) The XF-90 did have longer range than the others though, and was incredibly tough due to the overly heavy construction. One of the prototypes was used with testing of Nuclear explosions and survived. (with some warping, it's being restored to static display in damaged condition iirc)

But it doesn't really matter anyway since the whole penetration fighter project was cancelled, thus the winning XF-88 never entered service, though it was developed into the F-101.

[Elvis]

KK,

Thanks for the info on the F-80E. Mr.Baugher comes through again, eh?

--------------------------------

FBJ,

Man, is that ever a sexy beast!
Reminds me of an F-101, back in the days when it was runway model and being shot for Sports Illustrated covers.
Yeowch!


Elvis

[davparlr]

Originally Posted by FLYBOYJ

But then I think the next step was....

Lockheed XF-90

Shades of "Blackhawk"!

[kool kitty89]

That's he thought too:

The Lockheed XF-90 experimental long-range penetration fighter of the early 1950s always reminded me of the planes flown by the Blackhawks, who were comic book heroes when I was a wee lad. Hawkaaaaaa......!

And here's the Nuclear tests:

Work on the XF-90 was formally terminated in September of 1950. In 1952, the second XF-90A (46-68 was deliberately destroyed on the ground during a nuclear test at Frenchman's Flat in Nevada. The first XF-90A (46-687) was shipped to the NACA laboratory in Cleveland, Ohio in 1953. By this time it was no longer flyable, and was used for structural testing, exploring the limits of the extremely robust structure of the design. Presumably it was tested to destruction. In 2003, the hulk of the second XF-90 (46-68 was recovered by the USAF Museum from the Nevada nuclear test site. I assume that it will eventually be restored and put on display.

[davparlr]

Originally Posted by Elvis

What I always wondered about was why the swept wing/stabilizers concept wasn't tested on the P/F-80, as a means of improving its performance?
Maybe hindsight is 20/20, but that seems like one of the first things I would've explored, upon deconstruction of the ME-262.

Elvis

Probably because they recognized that the wing sweep on the Me-262 was to move the center of lift aft and not to improve performance at speed (which it must have done to a small extent).

[Elvis]

The sweep must have some performance enhancement qualities.
Both the F-86 and the F-84 picked up approx. 100mph over their straight wing counterparts, when they went swept wing, and both aircraft were subsonic (level flight).
However, you bring up a good point. That could very well be why they didn't go after the swept wing, to begin with.



Elvis

[kool kitty89]

The wing sweep of the Me 262 (as well as the DC-3, late Il-2, Me 163, XP-55, XP-56, Saab 21R etc) were not for trans-sonic and critical mach reasons, but the slight sweep (~17.8*) would have had some effect, albeit unintentional. (and only slight)

However German engeneers obviously did know the advantages of swept wings, and the Me 262 HG aircraft took advantage of this intentionally.
-The HG-I had a swept tailplane, low profile canopy and a standard wing except for a 35* LE sweep inlay section inboard of the nacelles. It was flight tested.
-The HG-II had constant 35* sweep with the same swept tail as the HG-I. (it was originally to use a V tail) It was completed but never flew. (damaged by bombing or ground accedent and never fully repaired iirc)
-The HG-III had a 45* sweep with the engines moved to the wing roots and the same swept tail. (HeS 011 engines were planned iirc) It did,'t leave the drawing board.

It was the HG design data that was utilized in the XP-86 project iirc.

[johnbr]

What the XF-90 needed was a pair of ge 404 that would get it going.

[kool kitty89]

No way to big... They thought of alternate engines but all required a considerable redesign to work.


The J34 was a very compact engine (25" diameter ~1,200 lbs) the most promising adaptation would be to the related Westinghouse J46 (29" diameter ~1,800 lbs with 4,000 lbf 6,100 lbf AB) but even that would have required a major redesign.

[Elvis]

Not having been there at that time, its kinda wild to imagine how early jet technology must've seemed like "Jules-Verne-come-to-life", back then.
Those engines sound so small and underpowered, by today's standards, but were "cutting edge" at the time.

I wonder, if it had existed at the time, whether the J85 could've been used on any of those early aircraft (262, P/F-80, F-1, Meteor, etc.).
I don't think they were very big, but put out a good amount of thrust (2850lbs.-5000lbs., according to the GE website).

Does anyone know if any of those early engines took well to having afterburners attached to them?
Did it make much difference in their thrust?




Elvis

[Elvis]

.

[kool kitty89]

The early whittle based designs (W.2 series, J31, welland, Derwent I-IV) ran too rich (by jet standards, as jets run very lean) to allow proper after burning. For the AB W.2/700 for the Miles M.52 supersonic a/c, a fan was added to the engine to provide sufficient airflow for the AB. (basically a rudimentary after burning low bypass turbofan)


And the J85 could have been used on many of the early designs, He 280, Me 262, Ho/Go 229, He 162, Meteor, and a few others. Often the engines were at the CoG so switching engine type wouldn't require ballast etc.

The Me 262 Project's reproductions use J85's.

[Elvis]

Groovy!

Thanks KK.



Elvis

[kool kitty89]

And another thing on the after burning, the Jumo 004 seems to have been adapted fairly well in the 004E. And the J35 and J34 were quite sucessful with after burners being produced in the early '50's. (the original designs originating from 1944-45, early if you include the TG-100 turboprop that the TG-180/J35 was developed from)