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A strange concept for McDonnell F-101 fighter

hesham

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Hi,

I can't understand this concept from NASA to McDonnell F-101
fighter.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660010757_1966010757.pdf
 

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flateric

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These are just aerodynamically shaped supports for a wind tunnel model.
They prevent streamflow interference with model fuselage/exaust combo while these particular experiments being performed.
 

Tailspin Turtle

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Could this be an investigation of the F-101's pitch-up departure problem? The wing tips don't need to be there because that was the initiator - sudden tip stall which moved the center of lift forward. Note the angle of attack measurement.
 

flateric

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Well, paper title says it itself

"EFFECTS OF BOATTAIL AREA CONTOURING AND SIMULATED TURBOJET EXHAUST ON THE LOADING AND FUSELAGE-TAIL COMPONENT DRAG OF A TWIN-ENGINE FIGHTER-TYPE AIRPLANE MODEL"

Also:

The effect of support-system interference on the data is not precisely known but is believed to be small because of the relatively large
distances existing between supporting members and the surfaces of the fuselage-tail component.
 

AeroFranz

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flateric said:
These are just aerodynamically shaped supports for a wind tunnel model.
They prevent streamflow interference with model fuselage/exaust combo while these particular experiments being performed.

Gregory's guess seems substantiated by the fact that there are 'jet simulator units' installed on the model. The F-101 and F-4 (which uses same exhaust/tail boom configuration) suffered from high drag in the subsonic regime with afterburner off, so they would be likely candidates for WT testing involving simulated engine exhaust.
Seems like mastering the aft-end shape of supersonic fighters was (and may still be) more of an art than a science. The example of the F-15 comes to mind. The aerodynamics are so bad it doesn't make a difference whether the nozzle 'turkey feathers' are on or off!

Oops...just saw Gregory's reply. I guess that confirms it. :)
 

Tailspin Turtle

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flateric said:
Well, paper title says it itself

"EFFECTS OF BOATTAIL AREA CONTOURING AND SIMULATED TURBOJET EXHAUST ON THE LOADING AND FUSELAGE-TAIL COMPONENT DRAG OF A TWIN-ENGINE FIGHTER-TYPE AIRPLANE MODEL"

That would have been my second guess...
 

shockonlip

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It's a new design from Star Fleet with an F-101 instead of the saucer !
C'mon you know that's it !!

Mr. Sulu, ... canon fire ... Now!

Larry
 

OM

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shockonlip said:
It's a new design from Star Fleet with an F-101 instead of the saucer !
C'mon you know that's it !!

Mr. Sulu, ... canon fire ... Now!

...Photon Torpedo roll bar, natch.
 
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