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Posted (edited)

There have been some recent threads of people questioning the performance of the AGM-88 HARM. I had posted this on hoggit but I guess I should also post it here for those who never visit hoggit.

Some of you may know me through:

 

https://forums.eagle.ru/showthread.php?t=257696

 

or...

 

https://forums.eagle.ru/showthread.php?t=257698

 

Recently I got the time to run cfd on the AGM-88, a project I've been planning on doing for months now it just took this long to get to it and to finish it. For this run, I generated a drag curve and then, via a small Matlab program just did a basic 'if this missile flew straight and level at x altitude what is its speed'.

 

prjt4Hs.jpg

1psVRQb.jpg-Cd0 - Drag curve (Thrust off)

bYS20fM.jpg-TAS vs Time

nIKOeDX.jpg-TAS vs Distance

SadR3uC.jpg-Distance vs Time

 

 

*Note*

 

--------

 

Ed thrust =

 

1sec - 58,726N Boost

 

20.4sec - 11,031N Sustain

 

BMS Thrust =

 

4 sec - 47,448N Boost

 

18sec - 7,907N Sustain

 

--------

 

Conclusions:

 

ED's drag curve is pretty close considering how off some are, and I commend them for being as close as they are to my expected results. It is my opinion, though, that based on my cfd results the missile though is still a touch too draggy. And for a missile that is supposed to both fly as far and as long as a HARM this small difference adds up. The bigger question though, of course, is whar are the correct thrust values? As you can see the difference in thrust between the BMS AGM-88 and the ED one can produce significantly different results. I hope this will A) cause the community to push ED to push the HARM up the reexamine list, and B) help people better understand its current performance.[/Quote]

 

- Validation is in the doc in the second link: https://www.dropbox.com/s/7t321bvz9zdz1xf/R24%20CFD%20Study%20V1.pdf?dl=0

 

Hopefully 9L or BigNewy can ask if the AGM-88 is on the list of missiles to get a CFD makeover. As just based on my results, and just looking at the fact the CD values for the HARM ARE THE EXCT SAME as the AIM-7 which to me just seems odd for a missile that is shaped very differently than the AIM-7, it seems that the drag is off.

 

 

-EDIT: Pictures Fixed

Edited by nighthawk2174
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