Republic XF-91 Thunderceptor variants

[Mark Nankivil]

Thanks guys - just got lucky in receiving these. That wav file made the dogs in the neighborhood howl in pain ;D

How about the XF-91 this time...

Enjoy the Day! Mark

 

[Steve Pace]

These Republic Aviation photographs clearly shows that the radar nosed Thunderceptor was designated XF-91A.

 

[airrocket]

If memory serves correctly it was dual power rocket and turbine.

 

[verner]

What's the purpose of the shiny bare metal triangle just above the wing?

 

[elmayerle]

What's the purpose of the shiny bare metal triangle just above the wing?

I may be wrong, but it looks like there may have been some inflgith capability to vary the wing's incidence relative to the fuselage. That bare metal triangle would be where the inboard edge of the wing would ride on the fuselage.

 

[saintkatanalegacy]

3-view of another variant(notice the difference in inlet design) from wikipedia

interestingly odd wing shape

 

[overscan (PaulMM)]

Evan is correct, it had a variable incidence wing.

 

[saintkatanalegacy]

aye, and upon closer inspection, we can see notches to determine the movable wing's current angle(in the picture it's a notch higher than the normal mode; kinda reminds me of a flanker's tail too ;D )

 

[Jemiba]

3-view from FlugRevue January 2010:

 

[AeroFranz]

The "polished triangle" can be seen on the tail of modern airliners which have variable incidence tail. It denotes the travel of the surface.
The explanation of the reverse taper wing planform can be found in the troublesome tip stall characteristics of early jets. Wing tip carry ailerons (usually), so stalling that section leads to loss of roll control (and it shifts the center of lift forwards with consequent nose up).
With normal taper, the chord at the tip is lower, with consequently lower Reynolds numbers. A section with lower Re number will stall at a lower angle of attack than one with higher Re. Hence if you have a wing with reverse taper, you should be able to stall the inboard section of the wing before the outer section and retain roll capability. I guess you would also get pitch down in that case. These days you tend to tailor the stall characteristics with leading edge devices and twist, but that entails other compromises.

One thing is for sure: the combination of variable incidence and reverse taper show that improving the stall characteristics of early jets was seen as a priority in those days.

 

[robunos]

From 'Aeroplane Monthly', April 1985, pp.172-6 :-

the original design was to have a butterfly tail, but it was
decided that this was one advanced feature too far, at least
initially. A butterfly tail tail was fitted later to the 2nd prototype.
The XF-91 was indeed mixed powered, using a GE J47 turbojet,
and a Reaction Motors XLR-11 four chamber rocket motor,
as used in the Bell X-1.
The first aircraft, 46-680, had the rocket tubes arranged two
above, and two below, the turbojet jetpipe, whereas the second,
46-681. had them arrranged in a diamond pattern, like in the X-1,
in an extended fairing below the jetpipe.

(engage 'Justo Miranda' mode...)


cheers,
Robin.

 

[robunos]

the rest........


cheers,
Robin.

 

[overscan (PaulMM)]

Merged topics...

 

[Justo Miranda]

(engage 'Justo Miranda' mode...)
From
-Airpower,may 2005
-Le Fanatique de l'Aviation ,Hors Série nº 21
-The World's Worst Aircraft
-Unknown Source
Post-1

 

[Justo Miranda]

From
-Airpower,may 2005
-Le Fanatique de l'Aviation ,Hors Série nº 21
-The World's Worst Aircraft
-Unknown Source
Post-2

 

[Justo Miranda]

From
-Airpower,may 2005
-Le Fanatique de l'Aviation ,Hors Série nº 21
-The World's Worst Aircraft
-Unknown Source
Post-3

 

[Justo Miranda]

From
-Airpower,may 2005
-Le Fanatique de l'Aviation ,Hors Série nº 21
-The World's Worst Aircraft
-Unknown Source
Post-4

 

[Stargazer]

Wow, don't I just LOVE it when the Justo Miranda mode is ON! LOL

Great gallery as usual, and a couple of surprises for me, such as the inflight picture of the V-tail variant from the rear right handside, which I'd never seen before.

 

[Justo Miranda]

 

[AeroFranz]

you're right Stephane, that shot is not only new to me but really shows the aggressive lines of that variant. VERY cool. Thanks Justo!

 

[bercr]

XF-91