Does your engine model/take into account base drag?
Yes I do !
For the drag what I’ve done is this :
I use an approximation of the G6 standard projectile drag curve.
It’s normally used for ballistics of bullets and artillery projectile, but here I’ve used it as an approximation of the shape of a missile (I also implemented G1 and G7 drag curves so I can switch easily). (BTW I used the G6 curve for the MICA)
On top of this my approximation of the drag curve is biased towards higher drag coefficients along pretty much the whole curve.
This bias helps somewhat compensate for the fact that I don’t take the drag of the fins into account.
Now for base drag :
I wasn’t able to find much experimental data on this and doing the math is way out of my skill set.
So instead I took one paper that looked at how base bleed devices help reduce the drag of artillery projectiles.
In this paper they found that base bleed can reduce the drag coefficient of the projectile by 13% along the whole curve.
I implemented this as a 13% reduction of drag coefficient whenever the missile is burning fuel.
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Pretty interesting work around! Good job. I do think it’ll likely be a decent way to go about it for planar finned missiles and 13% reduction during motor burn is likely actually on the conservative size.
Very nice simulation you got there.
The 30% increase for the MICA NG is probably a very conservative estimate since the missile got :
- An increase in propelant mass (reduction of electronics size)
- Improvement in propelant/motor technology (the initial MICA is 20 years older than the NG one)
- New propulsion with dual pulse instead of only a boost+sustainer. This tech is new and that’s why you find it only onto last gen missile (PL-15/I DERBY ER/ AIM-120D)
For reference the AIM-120D only upgrading to a dual pulse manage a 50% range increase over the AIM-120C7. (Not taking into acount the GPS thing)
From other source the MICA NG EM is said to have a 130km max range while the MICA NG IR is said to have a 100km max range. (Air et Cosmos Spécial Rafale F5). So compared to the 80 and 60km max range of those missile you get a 66% increase in range compared to the 30% mentionned.
You should try your simulation again but with those numbers
Perhaps the limiting factor ends up being battery time which isn’t a limitation with VL situations
Since the Air and Cosmos acticle mention a 130km max range i feel like this IS the max range where the battery still function.
If you go high enouth the battery will always be what limits the range.
For example if you launch a Super 530D at 15 000 and mach 1, the missile will have the energy to travel about 87km.
In reality it will self-destruct at 59km after running out of battery.
The worst exemple of this I’ve seen so far is the R-27ER.
In the same scenario it can travel 131km but runs out of battery at 72km. (intentional nerf ?)
Sadly, range figures without context are of no use.
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nope missile just had a 60 second battery life IRL, used same battery as all the other R-27s
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I just made this MICA range chart from sea level to 12km altitude.
Launch speed is 300 m/s TAS for all altitudes.
Battery lasts 130 seconds, here all missiles stalled before battery died.
M number to the right is max mach speed reached.
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this is interesting since while aero range overall is superior to the sparrow, sea level max range is 28% less than the sparrow before stall which shows the difference long burn sustaining motors can make at low altitude
Could you do one with 55 seconds battery time? Devs often go with battery time of the last gen missile. In the case of the MICA EM, they’ll look at Super 530D which has a maximum battery time of 55 seconds.
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This isn’t going to be pretty.
Since the MICA loft higth, time on target is a lot worse than a 530D for the same distance engagement.
A 55sec battery time probably means a 50km max range even at hight altitude
Low alt is high drag and long burn motors reduce base drag by a lot yeah
MICA doesn’t loft as high as R-77 or AIM-54 does as video shows, so hopefully not. On Razbam’s Super 530D white paper where they justify the performance of the missile, they indicate it has a more modest loft profile designed to increase average speed of the missile during the whole flight rather than increasing the range.
So I’m gonna take a wager that the MICA is supposed to have a modest loft trajectory that increases endgame speed.
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Are you sure the R77 loft, i tried to find info on this but cound’t manage to find a primary source that said that the R77 indeed lofted.
If it didn’t loft that could explain the limited range of 80/100km while the missile is bigger than an Amraam
I apologize, I meant R-77-1. There’s a video of it lofting on the R-77 thread
bigger doesnt necessarily mean more range (tho it helps) R-77 is basicly the same size as the AIM-7M, its actually a little smaller, and the AMRAAM according to one publicly available document matches/exceeds the AIM-7M range/engagement envelop noramlly, and exceeds its range when using command inertial nav. The R-77 also likely has a lot of trouble when it gets slow, seeing as its fins act as airbrakes between ~M0.8-1.3
That chart you’re thinking of has nothing to do with the AIM-120 or AIM-7Fs kinetics. It only compares what’s possible in terms of guidance.
We all understand and know that the AIM-7Ms kinetic range vastly outranges the semi-active guidance range which is determined by the seeker. Only thing one could reasonably conclude from this is that it is possible to fire the AIM-120 further than the range the AIM-7M can be fired from, even if it is a range it’ll never reach.
The AIM-120 or any fox 3s in general can be fired from 1,000km away, doesn’t mean it’ll ever get there kinematically. The chart is just to demonstrate the fox 3 capability.
Super 530D has been changed to 60s guidance time some time ago.
Here it is with 60s of battery :
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I will start working on implementing lofting next.
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