Forum: F-16 Design & Construction

Hey !

I am not a pilot myself but very interested in aircraft in general and the Viper in particular.

I was wondering if any of you active guys out there could help me out with my question.

How much do CFT's impact on the Vipers manouverability? Is there a marked and noticible difference when, for example flying a Block 50/52 with CFT's or without them on manouverability.

Also, what if the CFT's are fitted but empty i.e. not carrying any fuel. Will the empty CFT's still affect manouverability?

Basically, is manouverability affected, if at all, due to the additional weight of fuel, or the change in aerodynamic shape due to CFT's or both? And if both, how much is due to the change in shape and how much affect is due to the additional load?

Hope my question makes sense.

Any responses would be much appreciated.

Thanks.

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I guess you could compare this video to all those Thunderbird videos and get a general idea.

http://www.youtube.com/watch?v=hKxon9zEz0E

CFT's are cleared for the full 9G envelope. More info here: http://defense-update.com/products/c/F-16-CFT.htm

Thanks guys.

Cywolf32 .... yes, the CFT's are cleared for the full 9G envelope ..... that's fine. However, what I am interested in is whether active pilots notice a marked reduction in performance because of them.

The article you have linked in says ....

"The tanks have neglible effect on the aircraft agility, at subsonic speed, However, at supersonic speed, the drag is increased proportionally to the increase in speed. "

and

“A set of CFTs carries 50 percent more fuel than the centerline external fuel tank, but has only 12 percent of the drag.”

it also says:

"When fitted with CFT the aircraft retains almost the full handling qualities, flight limits, and signature."

what I'd be interested in to know how do pilots feel about this word "almost" in the above Smile

I guess the effect would be more noticeable in supersonic range as compared to subsonic ..... I would just like to get any feedback from pilots on how they feel with CFTs on ....

I'd like to hear some pilot feedback as well.
The following report on the indian Air Force MMRCA bidding speaks very well of the capabilities of both the F-16 nd F-18SH, even tho they are among the most dated designs of the competing platforms. In the case of the f-16, the author is consistent in noting how the cfTs affect aircraft performance.
http://carnegieendowment.org/files/dogfight.pdf

@ Popcorn ...... I read that very same report and thus had this question as well Smile

The above pdf report apparently has one mention only with regards to F-16's CFT and that being on implied increased RCS w/CFT configuration vs a clean F-16. Not too shocking. However one might be curious of the RCS comparison between F-16 w/ CFT only and F-16 with 2 wing EFT?

With regards to 'performance' and agility however... it would probably not take an active pilot per se, to deduce that an F-16 w/ CFT would retain majority of agility all while improving range and speed/acceleration vs a clean F-16 when carrying a centerline tank. So most likely yes, a CFT equipped F-16 would have multiple, significant performance benefits over a centerline equipped F-16.

And with the proper next-gen SoJ coverage in your package (under development now), it shouldn't be too relevant anyway in an RCS perspective, whether your F-16 variant has CFT or not.

edit: observe the 3:20 mark in this vid for instantaneous 'manouverability' of an F-16 w/ CFT, PLUS the draggy centerline tank still being dragged along in the DACT phone booth. Salute

http://www.youtube.com/watch?v=c-UHWJf0Gk0

geogen wrote:

The above pdf report apparently has one mention only with regards to F-16's CFT and that being on implied increased RCS w/CFT configuration vs a clean F-16. Not too shocking. However one might be curious of the RCS comparison between F-16 w/ CFT only and F-16 with 2 wing EFT?

With regards to 'performance' and agility however... it would probably not take an active pilot per se, to deduce that an F-16 w/ CFT would retain majority of agility all while improving range and speed/acceleration vs a clean F-16 when carrying a centerline tank. So most likely yes, a CFT equipped F-16 would have multiple, significant performance benefits over a centerline equipped F-16.

And with the proper next-gen SoJ coverage in your package (under development now), it shouldn't be too relevant anyway in an RCS perspective, whether your F-16 variant has CFT or not.

edit: observe the 3:20 mark in this vid for instantaneous 'manouverability' of an F-16 w/ CFT, PLUS the draggy centerline tank still being dragged along in the DACT phone booth. Salute

http://www.youtube.com/watch?v=c-UHWJf0Gk0

That MiG 29 sure has smokey engines.

My friend and I asked about this when they had a Block 60 at Holloman's 2007 Airshow. LM guy wouldn't say too much, just that it's pretty minimal and indicated any adverse effects they sure as hell weren't going to discuss because they could obviously be exploited by an adversary.

Other than that, they absolutely kill the supersonic drag so you aren't going to really be able to get very far going full AB.

Why would you need other input unless you do not trust the source? The article posted clearly states what CFT advantages/disadvantages are. Better range, no subsonic aerodynamic penalties, more weapons carrying capability, and full 9G envelope. Pretty straight forward. If you NEED to hear from a pilot to state that, ok. As far as RCS penalty, obviously taboo for an open forum.

I've heard the Block 60 jets, even with their extra powerful motors, are significantly lower performance than a clean Block 50/52. Just like on the mudhen, the CFT's really "drag" you down. Anybody's guess when you add a bunch of junk hanging off, but the Block 60's are more like strike/BVR fighters anyway. Not really meant to turn and burn. Awesome jets though, no doubt.

flyboy22 wrote:

I've heard the Block 60 jets, even with their extra powerful motors, are significantly lower (BFM) performance than a clean Block 50/52. Just like on the mudhen, the CFT's really "drag" you down. Anybody's guess when you add a bunch of junk hanging off, but the Block 60's are more like strike/BVR fighters anyway. Not really meant to turn and burn. Awesome jets though, no doubt.

The 52+ airframes themselves are already very dirty in comparison to the standard 50/52s

The CFTs are by itself an addition 900lbs dry weight penalty ..

To say the aircraft performing the same is akin to saying a mule is faster than a race horse :p

The G limits are lower on the CFT aircrafts too..

One thing that the 'older' generation viper drivers have an edge on the viper babies Wink

.. 3D fights .. with CFTs on .. you have to learn the BFM all over again Very Happy

Last edited by geogen on Mar 09, 2011 - 05:16 AM; edited 1 time in total

gunzo,

I'm curious now... what is the additional dry weight of a single 600 gal EFT plus the pylon? And what is the additional drag penality and fuel burn, necessary to hold the same cruise speed produced by the CFT-only airframe?

I'm sorry, but an F-16 powered by 32k lbf and loading CFT plus a centerline tank could out-fly any block 50/52/52+ flying with two wing EFT.

Do you disagree?

Flyboy,

Heard the exact same opinion from an IP that has flown virtually every config, both PW and GE powered, of Viper. Even with the bigger engine the 60 has a great cockpit anf ground-pounding ability, but due to the extra weight, air to air it ain't all that. Older, lighter, seemingly less powerful birds will out acelerate and out turn it .quite well.

Forum: F-16 Design & Construction

Impact of CFTs on the Viper's manouverability