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Blackbird
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F-101 Voodoo Range Question

Mon Sep 15, 2008 3:59 am

How did the F-101 Voodoo's achieve such enormous range considering they had such tiny little wings (they'd be flying at an uncomfortably high alpha, which produces excess drag, no?)?


Blackbird
 
Transpac787
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RE: F-101 Voodoo Range Question

Mon Sep 15, 2008 5:47 am

Didn't the F-101 carry massive drop tanks?? At least the interceptor F-101B's??


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ptrjong
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RE: F-101 Voodoo Range Question

Mon Sep 15, 2008 9:03 am



Quoting Blackbird (Thread starter):
they'd be flying at an uncomfortably high alpha, which produces excess drag, no?)

First, I think aircraft with a small wing can generally enough lift for cruise flight, and don't need to fly at a high angle of attack.

Quoting Blackbird (Thread starter):
tiny little wings

I don't think these are tiny little wings... it's not an F-104.

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Also, aspect ratio (span2/wing area) doesn't look too bad, which makes for efficiency.

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f4wso
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RE: F-101 Voodoo Range Question

Mon Sep 15, 2008 12:35 pm


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It is not unusual to see RF-101s with only one drop tank as the interference as the fuel in the second tank mostly offset the interference drag between the tanks. Ferry flights were at a slower speed so less drag leading to a benefit to having the second tank. The RF-101 had been retired from the KY ANG when I joined so I don't know the time frames of this.

I did some calcuations during a particularly boring part of C-130 conversion training to see the difference in drag and fuel savings for hauling those gi-normous external tanks around that are usually empty.

Gary
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keesje
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RE: F-101 Voodoo Range Question

Mon Sep 15, 2008 2:53 pm

Those were the big bomber stoppers from the cold war. Russian had similar machines to stop the B29s / B52s entering the vast Siberia Airspace, Tupolev Fiddler, Mikoyan Foxbat and Sukhoi Flagon come to mind..
 
Blackbird
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RE: F-101 Voodoo Range Question

Mon Sep 15, 2008 8:41 pm

Ptrjong,

Quote:
First, I think aircraft with a small wing can generally enough lift for cruise flight, and don't need to fly at a high angle of attack.

Evidently so, but still from what I remember it could do something like 3,000 nautical miles on just internal-fuel (which must have been *massive* as the J-57's are not the most efficient engines) which is quite high... From what I remember, generally long-ranged planes usually have to go to greater lengths to achieve the greater range in terms of drag-reduction and such.

Quote:
I don't think these are tiny little wings... it's not an F-104.

Actually, considering how light the F-104 is, I would not be suprized if the F-101's wing-loading might be a tad-higher (just max-weight vs wing-area by itself)

One thing I am wondering is if the tops and bottoms of the intakes act like a lifting device in their own right and add extra usable lift.

Quote:
Also, aspect ratio (span2/wing area) doesn't look too bad, which makes for efficiency.

I'm guessing the T-tail couldn't have hurt in terms of range (lower trim-drag), and as I said, I wonder if the tops and bottoms of the intakes (which are kind of flat overall) act kind of like a lifting device of their own and add extra useable area to the wing.


F4wso,

Tell me if I got what you said right...

It was quite common to carry one tank as it produced less interference-drag than two of them (as the airflow between the two tanks produces excess drag), and only carried two if they really needed a tiny bit of extra range, (as the extra tank just barely offset the interference drag) and often flew slower to get extra benefit out of it... and it would seem they rarely jettisoned the tanks?

Correct?


Blackbird
 
hunterson
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RE: F-101 Voodoo Range Question

Thu Sep 18, 2008 2:14 am

I think over and above the question of drag induced by the "massive" fuel tanks, one has to calculate the specific fuel consumption (spc) of the engines.
The F-101 was a large aircraft, even when compared to other same-generation types such as the F-106 and the F-4. It was able to carry a large amount of internal fuel, as well as 3 external fuel tanks, hence its relatively long ferry range of some 2200 miles, and corresponding combat radius typically quoted at 550-600 nm.
But we have to keep in mind that these figures always related to a optimal hi-hi-hi profile in subsonic speed for most of the mission duration, with perhaps an allowance for no more than 5-10 min. of supersonic dash with reheat ( afterburner ).
This was typical of all other contemporary types, both east and west, such as the F-102 Delta Dagger, F-106 Delta Dart, F-104 Starfighter, Sukhoi Su-9/11 and Yak-28P , as well as the supposedly ultra-long range Tupolev Tu-128 ( Fiddler).
Ultimately, they were all what we would refer to today as "gas-guzzlers", consuming huge amounts of fuel over speedy short distances, but flying far further at much slower cruising speeds and high altitudes in a relatively straight line..
 
Areopagus
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RE: F-101 Voodoo Range Question

Mon Sep 22, 2008 8:50 pm

Maybe some of the range came from being lightly built relative to other fighters. The F-101A was rated for 6.33 G's, and the F-101C was strengthened to 7.33 G's
 
Blackbird
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RE: F-101 Voodoo Range Question

Mon Sep 22, 2008 11:43 pm

Aeropagus

From what I checked, the F-101A was not hugely light (maybe for it's size it was, but it wasn't exactly a feather) at 24,970 lbs empty, 48,120 gross and 50,000 lbs maximum takeoff. The F-101B was around 28,000, and 52,000 at maximum weight.


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ba97
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RE: F-101 Voodoo Range Question

Sat Sep 27, 2008 2:59 am

I thought the F4 was large- I did not realize how large the Voodoo was. It seems like a huge leap in size occurred in the designs compared to previous fighters even though the shape (excuse my pedestrian approach here) seems rather basic. what brought about such a jump.
 
hunterson
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RE: F-101 Voodoo Range Question

Sat Sep 27, 2008 3:38 am

( Quoting Ba97 )


Quite simply, in my view, the "jump" was brought about by the availability of more raw power thanks to bigger, larger and more fuel-thirsty engines, such as the J75 ( on the F-105 ) and the J79 ( on the F-4 and the F-104 amongst others ).

The quest at the time was for ever more speed ( in a straight line at high altitude ), as well as more range and more fire-power. Obviously, this meant more fuel, and hence more weight and larger size, with very little attention to aerodynamics.


This was a common trend adopted by fighter designers all over the world, but especially in the USA, as exemplified by the whole so-called " century series " of large , heavy and fairly complex multi-role fighters, such as the F-100 Super Sabre, F-101 Voodoo, F-102 Delta Dagger, F-105 Thunderchief , F-4 Phantom and F-8 Crusader. It reached its zenith with the aborted YF-12 ( which was eventually adapted as the SR-71 Blackbird strategic recce aircraft), before advances in aerodynamic research led to the next generation of much more capable multi-role fighters powered with far more efficient turbofans with far lower fuel consumption rates and allowing for greater maneovrability, high speeds at all altitudes, longer ranges and heavier weapon loads, without the need for big sizes and ultra-heavy weights.

This was infact the generation examplified by the F-16 Fighting Falcon and the F-18 Hornet
as well as the relatively heavier F-15 Eagle and F-14 Tomcat. Also, around the world, it led to such types as the MiG-29 and Saab-39 Gripen.

Even the Soviets caught up with the trend and moved on from such enormous types as the TU-128 Fiddler and Su-15/21 Flagon to more realistic and operationally flexible types like the MiG-29 and the formidable Su-27/30 family.
 
ebj1248650
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RE: F-101 Voodoo Range Question

Sat Sep 27, 2008 1:51 pm

According to "American Combat Planes" , authored by Ray Wagner, the F-101 carried between 2,100 and 2,250 gallons of internal fuel, depending on which version of the F-101 you're talking about. That's about twice the fuel load of the F-102 and somewhat less than what the F-105 Thunderchief carried internally. In the case of the F-101, it was designed to be a long range escort fighter, initially at least, and had to have enough range, with air-to-air refueling, to escort bombers to Russia and back. Hope this helps.

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