This wasn’t really that hard I’d recommend you do some reading.
The issue is that since rockets eject mass, the regular SUVAT equations shouldn’t be used since they require constant mass.
It isn’t directly, but with enough parameters, drag could be additionally modeled since performance in a vacuum, so in air performance could be derived.
It doesn’t require that much thought, he’s just unwilling to actually do the math or provide any constructive base for his arguments. Makes ridiculous assertions, misreads documents and has outlandish assumptions.
How do you figure the AIM-54 (much larger missile, much lower thrust) has a top speed of mach 3 at sea level and mach 6 at higher alts but the R-27ER with 3-5x the thrust (and smaller) would not be capable of similar?
Have you tried giving more thought?
Clearly more than you’re worth, still waiting on like 12-15 sources for prior outlandish claims.
So you can show the R-27ER is overperforming? Because out of context, that’s what I implied he do. He made the assertion, up to him to prove it.
I don’t exactly know though it may be worth pointing out that the motor(s) are likely optimized for different altitudes and have different efficiencies due to a number of differences (fuel, packing factor, thrust curve, burn time, etc.) and nozzle designs that favor specific a given launch condition, also it is likely that missiles are optimized for specific types of aerodynamic drag within a given speed range so efficiency will likely vary significantly over any given motor firing / glide phase as conditions change.
We know the Russian and American propellants were similar at the time, with an ISP around ~250-268, the top speed would be at the end of the motor burn in each case since it should still have sufficient thrust over drag to accelerate in regards to the R-27ER when the AIM-54 would have been stuck at mach 3.
It’s really really simple, the R-27ER is a smaller missile and has at least around 2x the thrust in sustainer vs the AIM-54’s motor (if it was maintaining peak thrust still towards the end of burn).
Anyhow since we’re on the topic of physics, I made a report about the F-16 lacking instability of any kind even during maneuvers > 90 degrees AoA with coupled pitch + roll + yaw, truly a UFO right now so idk why it’s “borderline useless”… nothing can defeat it.
https://community.gaijin.net/issues/p/warthunder/i/OLiLWCU6c4tU
R-27ER has a ton of thrust for a short period of time. At low alts/short ranges, this will give it the expected very short time-to-target and very high relative speed.
But, at longer ranges the AIM-54’s hyper-aggressive loft profile comes into play. Launching at long ranges, the R-27ER is going to burn itself out while still being stuck in the highest-drag regimes, dramatically limiting top speed and efficiency. The Phoenix though probably isn’t drag-limited at all since it lofts so aggressively. Instead, it expands much more of its chemical energy increasing altitude and accelerating.
So, while in a vacuum, the R27ER will beat the Phoenix every day, the difference in designs means that the R27ER is going to spend most of its time outside of the vacuum (Low-medium alt acceleration) while the Phoenix accelerates much more (time) at medium-high altitude. It is possible that this advantage is enough to have the Phoenix out-speed the R27ER at altitude.
Do we know the average speed of an R27ER over a near-max range shot?
At high altitude the AIM-54 (IRL) reaches approximately mach 5.9 - 6 from 2.5 mach launch.
The R-27ER in a similar scenario, launched from 2.5 mach (in-game) will reach no more than mach ~5.5.
This is because at higher altitudes the drag is not the limiting factor, overall deltaV is.
Now, when I was discussing the top speed of the Phoenix earlier I was discussing it in a scenario wherein it would be accelerating at sea level without a loft… the top peed (drag limited) therein is mach 3. We can assume in this region the R-27ER will have the benefit in time to target out to a certain distance, but the longer burn time of the AIM-54 will allow it to maintain this top speed for quite some time and will eventually out-pace the R-27ER.
In my testing the R-27ER is outpaced by the Phoenix beyond 50-60km at medium to high altitudes. At this point it is as if one car got a 30mph head-start, and then another car after 15-20 seconds took off going 100… it (AIM-54) will pass the R-27ER at around 65-70km going significantly faster at that point due to the slower initial acceleration.
All numbers (except top speeds) are very approximate from memory and testing in-game.
Also worth noting, the Phoenix is significantly underperforming in-game currently and still outpaces the R-27ER like so.
Ah, yep all sounds about right to me. I just ran the numbers on another shot in that report and at 10k feet over 23 seconds its average speed was only Mach 2.3, though this was the 16g shot that gave us the number we’re stuck with today. (launched from mach .75 compared to the previously mentioned shot’s mach 1.5)
aim7 is not a good misile
f16 radar isn’t good
mig23’s mti isn’t affected by ground level multipathing; r24r in range = free kill
mig29’s radar is lackluster despite the range, but the r27er’s have a mind of their own + neither affected by multipathing. r27er in range = free kill.
Every missile is effected by multipathing, and the F16’s radar is technically slightly better than the Russian ones (better notch width)
Problem is the Phoenix is shit and you only have 2 + 4x9L
Also, MTI doesn’t negate anything since multipathing is CW wave to missile
Well AIM-7F is already far more reliable than S.530D
And for real,… if you feel AIM-7 is bad,… then i can’t make you to understand how many kills are done by 7’s today,…
It is not as good as R-27ER, i agree.
But it is far to be a Bad missiles nowadays.
he’s been wrong everytime, but mass only affects speed once we’re entering relativistic environments. The mass of an object however affects it’s acceleration.
For any object in flight, more mass means more weight. More weight requires more lift to counteract it. Achieving more lift for a given airspeed requires the aero-surfaces to generate more lift. Regardless of how they achieve this, through AoA increase or change in shape, there will be more drag. More drag influences top speed. Therefore mass does influence speed, even below relativistic effects.
oh in that sense yes it really does.
Anyway, MiG23M guy is just a russian coper who doesn’t see that the MLD will shiz anyday of the week on any other 11.3 be it legacy or new, but he can’t see it because there was 12.0 and also 12.3 now.
Not correct for all aircraft. Easy example is the MiG29, that produces so much lift at high speed that the aircraft has a negative angle of attack, which means that the parasite drag (which is dependant from frontal area) will probably be higher than the slight increase of induced drag that the aircraft would have if it weighted 1000Kg more.
And this doesn’t even consider how little induced drag is at small AoAs regardless.
To be fair tough, in the case of missiles mass has a big impact in the sense that acceleration will be slower, aka less speed reached before rocket motor burns out
Don’t really understand your point. The parasitic drag is there regardless, and if it needs to fly at a negative AoA at high speed that is a consequence of the aircraft’s design, not its weight.
Parasitic drag changes based on what the frontal shape is compared to the velocity vector, and the frontal shape at 0 degree AoA is very different from the one at, for example 20 degrees AoA. That parasitic drag increase is way more than whatever increase there would be in induced drag to get 1 or even a couple of tons extra lift at very high speeds.
More weight = more lift = wings won’t go (or at least won’t go as much) into negative AoA and stay closer to 0 degree (which 99% of the time corresponds to lowest frontal area)
