A-7D Instantaneous Turn Rate?

Cold war, Korea, Vietnam, and Desert Storm - up to and including for example the A-10, F-15, Mirage 200, MiG-29, and F-18.
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southernphantom

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Unread post08 Jun 2018, 20:16

I'm working on a personal project that requires ITR and Ps data (doghouse plots) at varying altitudes for a variety of different aircraft. I've had no trouble finding plots (some from manuals, some calculated by third parties) for the F-4, the Viper, MiG-21, and various Mirage variants, but cannot find anything for the A-7D. The dash-one on Avialogs only has steady-state/sustained turn radii, but is no help on ITRs.

I also cannot find a representative altitude/airspeed envelope plot for the aircraft. Does anyone here know where I might be able to find either of these items?
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sprstdlyscottsmn

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Unread post08 Jun 2018, 20:22

If the -1 has stall speeds you can use that to calculate a CLmax, and from there you can calculate G and ITR based on speed and altitude. Did the -1 have a V-n diagram?
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southernphantom

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Unread post08 Jun 2018, 20:31

http://www.avialogs.com/viewer/avialogs ... hp?id=4298

Yes, there looks to be a V-n diagram on pg. 464 (6-15).

Truth be told, I'm way out of my depth messing with this stuff - as my signature indicates, my education has me far more qualified on matters 1300ft underground, rather than any altitude above it! It sort of baffles me that no altitude envelope diagram was included, especially as the F-4 -1 has it and a whole mess of other relevant data.
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sprstdlyscottsmn

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Unread post08 Jun 2018, 21:17

Here is what I got for sea level and 20,000ft at 29,500lb.
A-7.PNG
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sprstdlyscottsmn

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Unread post08 Jun 2018, 21:32

And this is when I add the (hard to get detail) STR info for Sea Level.
A-7(2).PNG
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southernphantom

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Unread post08 Jun 2018, 21:48

Wow! I really do need to figure out how to do that stuff, it's all I can do to calculate turn radius given an altitude, Mach number, and turn rate :cheers:

Am I correctly interpreting your diagram as showing about a 19.5deg/s STR around .48 Mach? If so, that absolutely trounces the F-4 at sea level, based on this plot...
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southernphantom

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Unread post08 Jun 2018, 21:49

...and looks to give the A-model Viper a run for its money, given this plot is at 5000ft rather than MSL.
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sprstdlyscottsmn

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Unread post08 Jun 2018, 21:53

southernphantom wrote:Am I correctly interpreting your diagram as showing about a 19.5deg/s STR around .48 Mach? If so, that absolutely trounces the F-4 at sea level, based on this plot...

So, the problem with accuracy on the A-7 numbers is that the resolution for the turn radius is in 0.2nm increments, or 1,216ft increments. I could be off by 10 or 20% based on interpretation of the sustained radius chart. That aside, yes you are reading my chart correctly. I don't like the lack of accuracy for the raw data though.
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outlaw162

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Unread post09 Jun 2018, 00:08

The Guard A-7s with AMF (Automatic Maneuvering Flaps) could absolutely "trounce" an F-4 under those conditions.

The Tulsa Guard and the ABQ Guard put two of our Tinker F-4Ds in the dirt during maneuvering. Guys jumped out OK and learned the hard way you just don't slow up and turn with the AMF A-7.

Generally anything over 3 Gs was severe negative SEP. To sustain 10 degrees/sec at the 7.33 corner took somewhere around 135 degrees of bank. :shock:
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southernphantom

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Unread post09 Jun 2018, 01:56

outlaw162 wrote:The Guard A-7s with AMF (Automatic Maneuvering Flaps) could absolutely "trounce" an F-4 under those conditions.

The Tulsa Guard and the ABQ Guard put two of our Tinker F-4Ds in the dirt during maneuvering. Guys jumped out OK and learned the hard way you just don't slow up and turn with the AMF A-7.

Generally anything over 3 Gs was severe negative SEP. To sustain 10 degrees/sec at the 7.33 corner took somewhere around 135 degrees of bank. :shock:


Thanks for the input! I guess that makes sense when I really think about it. Presumably the A-7 regenerates energy fairly slowly?
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outlaw162

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Unread post09 Jun 2018, 15:27

Presumably the A-7 regenerates energy fairly slowly?


A master of understatement.

When the Kansas Guard started the ANG F-4 schoolhouse, the day came when they set up the first DACT with the Tulsa Guard lowly A-7s.

I was in F-4 school at the time and everybody was in Ops to listen to the first fight, a 1 v 1, ex F-4 FWIC IP against your average okie A-7 driver (a previous C-124 pilot). I'm sure all the F-4 guys felt this would be a valuable humbling experience for the attack community......

......When the dust cleared, the A-7 was camped firmly at the F-4's six. The F-4 driver wanted another chance and told the A-7 guy, "Okay, pass me on the left and we'll set up another one." The A-7 driver's reply said it all about 'energy regeneration',

"You don't understand." :D
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sprstdlyscottsmn

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Unread post09 Jun 2018, 15:29

outlaw162 wrote:Generally anything over 3 Gs was severe negative SEP. To sustain 10 degrees/sec at the 7.33 corner took somewhere around 135 degrees of bank. :shock:

Are you referring to the Double Ugly or the SLUF?
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outlaw162

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Unread post09 Jun 2018, 16:02

The SLUF, it took a 135 slice to sustain that roughly 10 degree/sec STR in the 15,000' regime. You didn't have too many defensive slices left before you ran out of altitude. :shock: I think the reggies called the maneuver 'posthole left/right'. With AMF which operated below 300 KIAS, it was better to just coax your opponent into a slow fight if you could.

I don't have detailed charts, but IIRC the R-o-T for the A-7 was 10 deg/sec STR (in a slice), 20 deg/sec ITR and plan on staying slow for a long time.

The F-4 wasn't that much better, maybe a couple of deg/sec in a shallower slice.
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Unread post09 Jun 2018, 19:26

Thanks for the stories, outlaw.
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edpop

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Unread post10 Jun 2018, 01:15

Anything here help you out??
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