And its quite a simple one, Climb at 45°. Probably after burn it just tries to keep the AoA where L/D is the highest
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It has to loft to improve range and end-game performance but also because the nozzle would have flow separation at sea level conditions.
Performance is optimized at 10-15km as shown.
The nozzle will have flow separation at sea level conditions?..
Can you please provide what you read. Thanks.
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Yeah, but im not sure exactly what the best way to test it will be. Debating between removing loft and manually firing at 45 deg or messing around with the loft code. Not sure if i’ll get it to follow the proper trajectory if I play with the loft code but we’ll figure that out later i guess.
Motor impulses and burn profile are a little different as well, more impulse than the 97000lb-s stated for the AIM-54, but less than the one calculated at 45kft for the AIM-54 using the thrust equation(~126559lb-s). its also 16 sec burn instead of 30, which leads to other differences like a faster climb but also lower time with base drag reduction from the motor burn.
I could also likely make a “copy” of it using the AIM-54 body and modifying the motor to fit the values to see how it performs.
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That’s because the Eagle uses an entirely different motor. A 489 pound motor vs a 440 pound motor. The Eagle has higher thrust grain pattern than the Mk47 and a resultant lower burn time. The Mk47 is ~30 seconds and 3226 pounds thrust at ~10-15km
Additionally, the AIM-54 will not have nearly as high of an improvement in drag during missile burn time because the nozzle is not nearly the width of the missile. This causes turbulent flow, and not a streamlined teardrop shape at the rear of the missile as it does much more closely on AIM-7 and AIM-9.
Therefore, any attempt at increasing thrust to account for reduction in drag during missile burn time should account for the less efficient teardrop due to the small size of the nozzle.
One could argue that perhaps at higher altitudes there is underexpansion at the nozzle that increases the width of the cone… but this would reduce the efficiency of the rocket motor. Overexpansion of the nozzle would cause a turbulent exhaust (non-aerodynamic)… and could have flow-separation issues that damage the missile. I would argue that the thrust is accurate as-is because it is already modeled for 10-15km altitude in both average thrust as well as burn time… and for these reasons it should not be increased to account for reduction in drag during motor burn time, either. If it is… I would hope only 5-10% AT MOST.
Neither does this missile.
That’s a hypersonic air to air missile by the way.
You are coming to random conclusions again.
Can you please share what you read to determine the above so we may review?
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I would like AIM-54 to achieve Mach 6 so it’s easier to use at ranges up to 40 km (this is the most relevant range for today’s AIR RB)
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If they correct the top speed, they’d also need to increase the drag to decelerate it as it should after it is done burning. A higher top speed without the other improvements would suggest based on current testing that it would begin to overperform in time to target for certain scenarios.
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For real.
Because the R27ER can be launched completely from sea level up 90 degrees, maneuver and still accelerate rapidly to Mach 3.5 less than 7 seconds to hit a supersonic evading target 10k feet up.
I have video of this insane performance and will share when I get home. (In proper thread)
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I just want it to be modelled accurately, which afaik it isnt. Theres been strong discussion about this in the past, between loft profile, drag, and now AAT thrust, but due to evidence being sparse and certain individuals arguing solely for the sake of arguing, its a bit hard to get any actual bug report going for it. Doesn’t help if info is being concealed either.
As for the seeker and guidance code, that’s very clearly wrong just comparatively to the AIM-54A, but no documents give explicit information, so afaik gaijin will just continue to pull the “we need exact info, otherwise kick rocks NATO scrubs, the US sucks at making radars and missiles, glory to russia” card.
The fact the AIM-54A remains effectively a direct improvement over the AIM-54C in all regards in-game is a bad joke.
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Hecklers never stopped me from reporting and fixing issues when there was actually something to be reported. You said you stopped reporting because you didn’t feel like Gaijin would fix it regardless.
Go ahead, report AAT. You’ll be told the same thing that I’ve been telling you… you’re wrong. The AIM-54 thrust and burn time is quoted from high altitude as all its’ predecessors were. You’re double dipping thinking AAT is an issue.
You never asked me what I was using as reference for the information you were being quoted. Did you expect me to share data with you when I was never once contacted by you in regards to it? When you allegedly had me blocked but consistently liked replies to any of my posts or reported them until it was pointed out you were doing so? Perhaps had you behaved more professionally and took part in the discussion rather than just dismissing anything that didn’t agree with you we wouldn’t be in this predicament.
Not super relevant in-game, but while digging through sources I found out the AIM-54C+'s guidance section was used for the first powered space intercept
https://www.thespacereview.com/article/4622/1
which is just really cool imo
Also, some more details about the AIM-54C’s digitization:
https://scholarworks.calstate.edu/downloads/c534fr923
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Just noticed that the “Outsiders view of the Phoenix”, often quoted as the source for the impulse of the AIM-54, is quoting Jane’s, famously not an accepted source for Gaijin…
It also never claims at what altitude those thrust/impulse figures are for.
Also states its only using public sources (from 1977 and before)
@Gunjob any idea if gaijin has any other source regarding the motor characteristics for the MK 47 Mod 0/1?
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They quote primary sources regularly in the document. The fact that the specific number came from Jane’s (according to them) is only testament to the fact that the total impulse was (at the time) marked “confidential” and could not be shared from the primary sources available.
I recommend taking a look at the sources used by DCS to recently update / amend the performance of their AIM-54. They confirm the total impulse is less than 100,000s regardless of altitude.
To amend myself, under the blast cap at the rear of the nozzle is the actual size of the nozzle… much smaller than the 10" diameter I had assumed based on the previous measurement.
I am getting 477 pixels diameter (380mm missile…) 380 / 477 = 0.7966 mm per pixel.
I am getting 151 pixels diameter for the nozzle… which is 151 x 0.7966 = 120.3mm diameter.
So, it appears the rocket nozzle is a measly 4.7" based on this image if I am seeing what I think I am. That shows a much larger discrepancy in the previously reported math that assumed the nozzle to be the full diameter of the rear of the motor.
Of course, it doesn’t matter because the given thrust and total impulse is already for 10-15km alt as shown with the standard characteristics for the Eagle motor.
There is also another datapoint we can test @DirectSupport
A SAM-launched Phoenix (unmodified) was able to physically travel 22km down-range in 90 seconds. This is more than twice the traveling distance of the SeaSparrow according to China Lake.
Just another datapoint for testing purposes. I say we’d be better using our time comparing the performance of the Phoenix with various loft profiles in this type of condition.
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22km is really impressive for a rather large heavy missile I would have thought.
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Just a reminder that is not the target distance at launch, that is the actual distance from launch site traveled laterally across the ground for the missile in 90s. That is the total distance covered.
@MythicPi claimed the SeaSparrow to be capable of intercepting a target when launched at 26km, but the intercept distance is much shorter of course. We have the time to distance covered here, so we can evaluate the sea level performance of the missile and extrapolate from there quite well.
We can assume the 90s distance traveled was not the maximum, as well.
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It’s actually very impressive.
Yes, thar is a heavy air to air missile not designed to be fired from ground and a dead stop. It still flew more than twice the range of a sea sparrow.
That is a powerful motor.
It’s so fast took off from a dead stop from the ground and covered over 13 miles in 90 seconds.
Now how fast you think it is going to be going traveling from the gate as it is launched by a tomcat going near supersonic?
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