AIM-7 Disable loft please - Page 5 - ED Forums
 


Notices

Reply
 
Thread Tools Display Modes
Old 11-12-2019, 05:02 PM   #41
GGTharos
Veteran
 
GGTharos's Avatar
 
Join Date: Nov 2004
Posts: 30,266
Default

Given how the sparrow loft is meant to be used (knowledge gained from limited materials), no it wouldn't.

Sparrow loft is quite specifically intended to extend Rmax some 20%. It is activated by selecting loft AND pitching the aircraft up. There are other logic rules around the activation which I don't recall off the top of my head.

Missile loft implementation is not the same or equal for all missiles IRL.
__________________

Reminder: SAM = Speed Bump
I used to play flight sims like you, but then I took a slammer to the knee - Yoda
GGTharos is online now   Reply With Quote
Old 11-12-2019, 05:34 PM   #42
Rabbisaur
Member
 
Join Date: Apr 2014
Posts: 179
Default

I think minimizing time to impact is much more important than increase Rmax. IRL the algorithm cannot be this ridiculously simple as only involves middles school mathematics...

Calculus is a must here to solve the optimization problem for either Rmax or time to impact. Of course, only very basic Calculus is involved here...
Rabbisaur is offline   Reply With Quote
Old 11-12-2019, 06:18 PM   #43
Exorcet
Senior Member
 
Exorcet's Avatar
 
Join Date: Jun 2009
Posts: 2,779
Default

Quote:
Originally Posted by GGTharos View Post
Given how the sparrow loft is meant to be used (knowledge gained from limited materials), no it wouldn't.

Sparrow loft is quite specifically intended to extend Rmax some 20%. It is activated by selecting loft AND pitching the aircraft up. There are other logic rules around the activation which I don't recall off the top of my head.

Missile loft implementation is not the same or equal for all missiles IRL.
If we're modeling the real missile, then it is what it is. However the range suggestion is supposed to be a "good enough" stand in if I'm understanding correctly.


From my own testing I've seen superior performance gained from lofting within 20 nmi (again I admit to having to deal with the AI, which can bias the tests), and of course Rmax is going to vary with altitude anyway.
__________________
http://i280.photobucket.com/albums/kk187/Exorcet/F-15singaturebaseACOmodifiedcomp-1.jpg
Win 7 64 i5-6600K 3.6 GHz 32 GB RAM GTX970 4GB -- A-10C, F-5E, Su-27, F-15C missions in User Files
Exorcet is offline   Reply With Quote
Old 11-12-2019, 07:15 PM   #44
GGTharos
Veteran
 
GGTharos's Avatar
 
Join Date: Nov 2004
Posts: 30,266
Default

Quote:
Originally Posted by Rabbisaur View Post
I think minimizing time to impact is much more important than increase Rmax. IRL the algorithm cannot be this ridiculously simple as only involves middles school mathematics...

Calculus is a must here to solve the optimization problem for either Rmax or time to impact. Of course, only very basic Calculus is involved here...
We have almost no insight into the actual implementation other than instructions written in the manuals.

You might be right, you might be optimistic - that last part shouldn't be too much of a surprise.

A long range AIM-7 shot is only good if you have a really big RCS target, since the sparrow is pretty much lock on right off the rail and is then guided via PN with some range-to-target (or TTG?) based capability schedule.
__________________

Reminder: SAM = Speed Bump
I used to play flight sims like you, but then I took a slammer to the knee - Yoda
GGTharos is online now   Reply With Quote
Old 11-12-2019, 07:17 PM   #45
GGTharos
Veteran
 
GGTharos's Avatar
 
Join Date: Nov 2004
Posts: 30,266
Default

Quote:
Originally Posted by Exorcet View Post
If we're modeling the real missile, then it is what it is. However the range suggestion is supposed to be a "good enough" stand in if I'm understanding correctly.


From my own testing I've seen superior performance gained from lofting within 20 nmi (again I admit to having to deal with the AI, which can bias the tests), and of course Rmax is going to vary with altitude anyway.
By all means, suggest a better range.

However the current lofting algorithm fails to take anything but range into account. What works for you now might not work under different circumstances, ie a high-low shot.
__________________

Reminder: SAM = Speed Bump
I used to play flight sims like you, but then I took a slammer to the knee - Yoda
GGTharos is online now   Reply With Quote
Old 11-12-2019, 07:41 PM   #46
Rabbisaur
Member
 
Join Date: Apr 2014
Posts: 179
Default

Quote:
Originally Posted by GGTharos View Post
We have almost no insight into the actual implementation other than instructions written in the manuals.

You might be right, you might be optimistic - that last part shouldn't be too much of a surprise.

A long range AIM-7 shot is only good if you have a really big RCS target, since the sparrow is pretty much lock on right off the rail and is then guided via PN with some range-to-target (or TTG?) based capability schedule.
I mean the current implementation by ED or the proposed possible future implemented in this thread are all too simple to be efficient. If you look into the code of current AIM7M/MH lofting logic: It only looks at the distance between you and the target. If it is longer than about 5NM, then aim7 flys initially flys at the required angle plus 30 degree up for four seconds. Then resume on an intercepting course to the target.

I would say a six grader can write a better algorithm than that. If the real missiles engineers do something like that then he should be tied on the missile and fired.

At least one should consider the time of impact and also the lofting trajectory should be optimized as well. You are not shooting 1 dollar 556 bullet after all. The cost of one missile should be enough to at least hire a college graduate to work on the optimization problem.

That is basically why many others and I think the current lofting mechanism of AIM7 on F15 is a bug. The missile will work much better if this kind of lofting behavior is disabled.

Last edited by Rabbisaur; 11-12-2019 at 07:45 PM.
Rabbisaur is offline   Reply With Quote
Old 11-12-2019, 07:57 PM   #47
Exorcet
Senior Member
 
Exorcet's Avatar
 
Join Date: Jun 2009
Posts: 2,779
Default

Quote:
Originally Posted by GGTharos View Post
By all means, suggest a better range.

However the current lofting algorithm fails to take anything but range into account. What works for you now might not work under different circumstances, ie a high-low shot.
Generally I've found the 7M to work for me as it is now. A missile lofting for a close high-low shot can be exploited, but from what I've seen if the target turns to run, the loft tends to do better as the non loft shot just bleeds off all of its speed in dense air. Also as far as I know the 7F isn't meaningfully inferior in DCS (please correct me if I'm wrong), so carrying them alleviates the problem if you don't like to loft. If the F has reduced seeker performance as compared to the real M, then I guess changing the loft behavior makes more sense.


As far as loft cut off range, I'd want to say maybe 7-10 nmi. I'll have to see if I still have the tracks comparing F and M. 20 nmi is probably OK above 30000 ft, but if you have to shoot lower I'm pretty sure it's a detriment.
__________________
http://i280.photobucket.com/albums/kk187/Exorcet/F-15singaturebaseACOmodifiedcomp-1.jpg
Win 7 64 i5-6600K 3.6 GHz 32 GB RAM GTX970 4GB -- A-10C, F-5E, Su-27, F-15C missions in User Files
Exorcet is offline   Reply With Quote
Old 11-12-2019, 07:57 PM   #48
zhukov032186
Senior Member
 
zhukov032186's Avatar
 
Join Date: Nov 2016
Location: Fort Worth, Tx
Posts: 2,516
Default

^ Nice angst. (not you Exorcet, you ninja'd me)
__________________
Zhukov attacks *FORUM USER* with Legendary Trollsword!
*FORUM USER* Constitution save roll.... Fail!
*FORUM USER* afflicted with ''Hurt Feelz'', -1 Concentration for two rounds
zhukov032186 is offline   Reply With Quote
Old 11-12-2019, 08:02 PM   #49
GGTharos
Veteran
 
GGTharos's Avatar
 
Join Date: Nov 2004
Posts: 30,266
Default

Quote:
Originally Posted by Rabbisaur View Post
I mean the current implementation by ED or the proposed possible future implemented in this thread are all too simple to be efficient.
The proposal is an absolute stop-gap and everyone knows it.

Quote:
If you look into the code of current AIM7M/MH lofting logic: It only looks at the distance between you and the target. If it is longer than about 5NM, then aim7 flys initially flys at the required angle plus 30 degree up for four seconds. Then resume on an intercepting course to the target.
I maintain the missile mod, I know all about it.

Quote:
I would say a six grader can write a better algorithm than that. If the real missiles engineers do something like that then he should be tied on the missile and fired.

At least one should consider the time of impact and also the lofting trajectory should be optimized as well. You are not shooting 1 dollar 556 bullet after all. The cost of one missile should be enough to at least hire a college graduate to work on the optimization problem.

That is basically why many others and I think the current lofting mechanism of AIM7 on F15 is a bug. The missile will work much better if this kind of lofting behavior is disabled.
I've already sent a better algo to ED.
FYI, yes, it does operate on TTI - there is also doubt that it is applicable to the MH, which seems to do something far simpler.

The 7M should have no loft at all.
__________________

Reminder: SAM = Speed Bump
I used to play flight sims like you, but then I took a slammer to the knee - Yoda
GGTharos is online now   Reply With Quote
Old 11-12-2019, 08:04 PM   #50
GGTharos
Veteran
 
GGTharos's Avatar
 
Join Date: Nov 2004
Posts: 30,266
Default

Quote:
Originally Posted by Exorcet View Post
Generally I've found the 7M to work for me as it is now. A missile lofting for a close high-low shot can be exploited, but from what I've seen if the target turns to run, the loft tends to do better as the non loft shot just bleeds off all of its speed in dense air. Also as far as I know the 7F isn't meaningfully inferior in DCS (please correct me if I'm wrong), so carrying them alleviates the problem if you don't like to loft. If the F has reduced seeker performance as compared to the real M, then I guess changing the loft behavior makes more sense.


As far as loft cut off range, I'd want to say maybe 7-10 nmi. I'll have to see if I still have the tracks comparing F and M. 20 nmi is probably OK above 30000 ft, but if you have to shoot lower I'm pretty sure it's a detriment.
M should have no loft, only MH. Regarding tail-aspect shots, I agree. But frankly that close range thing as it is right now is extremely annoying. In MP this is pretty much on the border of the range you're taking shots at.

Regarding 7F, should be a LOT more vulnerable to chaff. I'd be ok with 10nm. I consider it slightly too close, while at the same time it doesn't really cover your tail-chase use case. This is because the whole thing operates on range instead of TOF.
__________________

Reminder: SAM = Speed Bump
I used to play flight sims like you, but then I took a slammer to the knee - Yoda
GGTharos is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT. The time now is 10:21 PM. vBulletin Skin by ForumMonkeys. Powered by vBulletin®.
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.