Viper and Tomcat showdown

Agreed, it will never be a fair fight but how would the F-16 match up against the ... ?
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Raptor_One

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Unread post08 Nov 2005, 22:22

I'm not oh so wrong and unless you're talking about some ultra-cold day with some ultra-light jet, you are not +Ps in ANY block F-16. I have EM diagrams that clearly show this. I NEVER said that you couldn't accelerate in a 9G turn either. There are DEFINITELY large portions on the 9G limit at the top of the doghouse where any F-16 block is +Ps.

Just so you know I am not talking out my **** here, I have brought up an EM diagram for an F-16C Block 30 (F110-GE-100/Big Mouth). Conditions are sea level, 20,000 lbs GW, drag index = 0, standard day, max AB. On the CAT I limiter pulling 8G or 7G in this configuration equates to an airspeed of Mach 0.51 (~ 335 KIAS) or Mach 0.46 (~ 305 KIAS) respectively. At 7G on the CAT I limit the Block 30 is almost exactly -400 Ps. At 8G it is even lower (i.e. it is more negative) than -400 Ps.

2sBlind stated the "Blk 50/52 Viper can accelerate in a 7-8G limiter-pull turn to a 9G one." The Block 30/BI has even better EM performance in this region than the Block 50 or 52, but it certainly is not +Ps at 7-8G ON the CAT I limit. It is -400 Ps or less. I'm no F-16 pilot, but I know quite a bit about the F-16's EM performance. I think you just misunderstood what I was responding to. I take it you are an F-16 pilot so you know full well that the F-16 (any block) is not accelerating on the CAT I limit at 7 or 8G. Like you said, the F-16 is only going to accelerate in a 9G maximum performance turn.
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Laxman

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Unread post11 Nov 2005, 12:48

Again I urge you to talk to the pilots that actually fly the jet
Harrumph!!!
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hansundfranz

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Unread post11 Nov 2005, 15:04

Laxman, if you´d take a moment to think what "on the CAT1 limit" actually means you´ll understand that raptor is right.

And when it comes to flight performance enineering data (presented as charts most of the time) is much better then pilot anecdotes.
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Raptor_One

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Unread post11 Nov 2005, 17:16

Laxman wrote:Again I urge you to talk to the pilots that actually fly the jet


Are you saying that I don't know how to read an EM diagram for the F-16 Fighting Falcon? The only thing that's different about an F-16 EM diagram is that instead of a lift limit boundary there is CAT I limit boundary. The 7 and 8 G lines that intersect the CAT I limit boundary are in the negative excess power region (-400 Ps or higher). Negative Ps means that you are losing energy and not gaining it. It's really that simple. No F-16 pilot would claim that the F-16 can gain speed when pulling 7-8 G right on the CAT I limit (max performance turn).

And like I said before, the case where you're losing altitude in a turn to maintain speed is academic. Many modern fighter aircraft can accelerate in a 7 or 8 G turn with the help of gravity. The F-14 certainly can. Both the F-16 and F-14 would need to pull a very aggressive slice maneuver to maintain, let alone gain speed in a 7-8 G turn though.
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ts79

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Unread post11 Nov 2005, 17:20

7-8 g turn yes, but a viper can accelerate in a 9 g turn without being excessively nose low, but I think you mentioned that in an earlier post...but just to clarify...
...and anything else is rubbish
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Raptor_One

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Unread post11 Nov 2005, 17:43

ts79 wrote:7-8 g turn yes, but a viper can accelerate in a 9 g turn without being excessively nose low, but I think you mentioned that in an earlier post...but just to clarify...


Any block F-16 (even a heavy block 42 with weak F100-PW-220 engines) can accelerate while pulling 9 G in a LEVEL turn within certain speed ranges so long as the altitude isn't too high. This sustained 9G level turning capability disappears somewhere between 10 and 15K ft. depending on which block you're talking about.

Another thing to keep in mind is that this sustained 9G turning capability requires the weight and/or drag index of the aircraft to be relatively low.
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Laxman

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Unread post14 Nov 2005, 10:07

hansu, I know what a CAT I limiter is, I live it on a daily basis

"Any block F-16 (even a heavy block 42 with weak F100-PW-220 engines) can accelerate while pulling 9 G in a LEVEL turn within certain speed ranges so long as the altitude isn't too high. This sustained 9G level turning capability disappears somewhere between 10 and 15K ft. depending on which block you're talking about."

Shack
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hansundfranz

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Unread post14 Nov 2005, 16:11

hansu, I know what a CAT I limiter is, I live it on a daily basis

I don´t think so, Please try to define the term.

To me the CAT1 limit is the AOA for given G limit. In the doghouse chart it is the left side of the charts. On the right side you have the constant g limit (and not the CAT1 limit)

"Any block F-16 (even a heavy block 42 with weak F100-PW-220 engines) can accelerate while pulling 9 G in a LEVEL turn within certain speed ranges so long as the altitude isn't too high. This sustained 9G level turning capability disappears somewhere between 10 and 15K ft. depending on which block you're talking about."


In the chart I´m looking at (FE-110 GE 100 Big mouth, seal level, DI=0 GW = 20,000) you have posetive Ps at 9g above mach 0.66

However this is not 7-8 g on the cat1 limit. It is on the 9 g limit.

7 g on the cat 1 limit is at mach 0.46 with Ps = -400
8 g on the cat 1 limit is at mach 0.51 with Ps = -450 or so.

In the charted condition the jet can accelerate on the cat1 limit below mach .32 and below 3.5 g . It will accelerate until it reaches that point but not any further (while staying on the limiter)
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Raptor_One

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Unread post14 Nov 2005, 16:30

Hans is correct. The CAT I limit is valid up to 9G. Once you hit 9G you just have the 9G limit. No F-16 I know about is +Ps while turning at the CAT I limit unless you're talking about the case of low Mach, low G that Hans mentioned above. This is somewhat trivial though since F-16 pilots generally avoid fighting so slow on the CAT I limit.
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