Forum: General F-22A Raptor forum

Last edited by firstimpulse on Apr 20, 2012 - 04:40 AM; edited 1 time in total

Found this while looking through fighter videos on youtube. The anime clip shows a flashy sea battle sequence between a fictional Japanese carrier group (and its fictional X-32 like fighters) and three alien aircraft, with a prototype called Yukikaze playing hero. However, the last 30 seconds of the video are what promted me to post. Yukikaze, before taking off from the carrier, pulls a stunt beyond what might be possible, while never going further than ten meters from the carrier.

Go to 6:32 to skip to the stunt.
http://www.youtube.com/watch?v=XXadee4y5PQ

My question is, could a Raptor pull that off?
Could any craft pull that off?

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In a word: no. I won't even bother to do the force/acceleration calculations; the engines would not be able to overcome the fighter's inertia and achieve zero velocity unless they are some fictional 1000000kN-thrust powerplant that's probably alien or technobabble in origin.

The negative G pushover around 2:30 probably would have killed the pilots, unless I'm mistaken.

southernphantom wrote:

In a word: no. I won't even bother to do the force/acceleration calculations; the engines would not be able to overcome the fighter's inertia and achieve zero velocity unless they are some fictional 1000000kN-thrust powerplant that's probably alien or technobabble in origin.

It looks like there was some vectored thrust coming from the front end on that trick. So, no, not something the Raptor could do, all considerations of thrust and acceleration magnitudes aside.

Thrust isn't the problem, as the F-22 has thrust to weight ratio greater than 1.0 The problem is lack of control. TV can provide adequate pitch control, but at very low airspeeds, roll and yaw would be a problem.

Another thing -- it would take some out of this world durability to fly through the superstructure of a warship and come out the other side intact. I suppose this "Snow-wind" must also have some interesting warheads on it's missiles if it can bring down something like that.

@count_to_ten, that enemy fighter didn't survive. It was a kamikaze attack. There were three at first, then one hit one of the carrier's escorts. The other two were downed before they reached their targets.

@Johnwill, that's what I was thinking. Also, don't carriers normally have netting or catwalks just beneath the edges of the flightdeck? Either of those could've fouled up the landing gear and caught it like a fly in a web.

Maybe wrong of me to assume it's this simple, but I think to calculate if it's theoretically possible, you'd have to know the exact weight of the airplane + how far/long it fell down and calculate the kinetic energy of the fall.

After that, you will need to know the total engine output of the engines and put that against the kinetic energy of the airplane's fall.

For the following scenario, let's assume the plane in question is an F-22.
* The plane weighs 23.800kg with 50% fuel.
* The angle it falls down is exactly 90 degrees (nose pointing up).
* The pilot and airplane have infinite G tolerance.
* Each engine produces lets say 150kN at that altitude.
* The engines spool up to max thrust instantaneously.
* The plane "falls" for 1 second before the pilot cranks up the engines to max output.

(A) Calculating the objects Kinetic energy:
1 (second) X 9.8N (1G acceleration) x 23.800(kg) = 233.240N

(B) Calculating the objects propulsion energy:
2(engines) x 150.000N(thrust per engine) = 300.000N(total thrust)

What we see here is:
(A) Is the total movement/kinetic energy after 1 second that the object is experiencing by falling down, caused by its mass and the earths' gravity (233.24kN).
(B) The total amount of thrust/energy that the plane can produce into the exact opposite direction of the earth's gravity (300kN).

(B)300.000N - (A)233.240N = 66.760N. This means that after 1 second of free-fall, the engines will be able to stop the plane from falling and start accelerating it upwards slowly with positive 66.760N. Once the plane stops falling, the acceleration will of course increase since the planes "negative" kinetic energy has already been nullified in the first second.

This is all theoretical and I am assuming many improbable things to make this work like instantaneous max engine output, infinite G-tolerance, nose pointing 90 degrees up at all times etc. Those are all big problems that will arise if this is ever tried in real life and I doubt that it's currently "doable" in real life but theoretically, it is certainly possible with the F-22 for example (or any other jet with a positive thrust-to-weight).

IT..

No. The F-22 can't go in reverse on engine power alone.

firstimpulse wrote:

@count_to_ten, that enemy fighter didn't survive. It was a kamikaze attack. There were three at first, then one hit one of the carrier's escorts. The other two were downed before they reached their targets.

Looked like it went through and came out the other side. Given the all three were plowing through hundreds of CIWS shells without noticing...
But, I guess I don't have the rest of the context of the series.

Yep, since the late 1950's...

http://www.youtube.com/watch?v=oImq1glnOds

All you need is a 130K lb thrust rocket strapped to your Super Saber!

LMAO

TEG

See also:

http://www.youtube.com/watch?v=cE6QmjAlHT8

Ah ZELL, another crazy idea from the 1950s. It was never truly practical and if you needed something that could do that you just launched a BOMARC.

Back to topic johnwill put it perfectly. The engines can provide enough thrust to counter the weight and drag at those speeds would be non-existent due to zero airspeed but yaw and roll control would be absent due to the aerodynamic control surfaces needing a non-zero flow velocity just to work with any sort of authority. Any perturbation to the system and you will be screwed.

Quote:

Looked like it went through and came out the other side. Given the all three were plowing through hundreds of CIWS shells without noticing...
But, I guess I don't have the rest of the context of the series.

You're right about the CIWS... Either the fighter was going too fast (would Mach 2ish be enough?) or the shells were bouncing off. The bad guys are portrayed as having the performance and durability of a 4.75 gen fighter (Su-35BM would be a good comparison) although with much better airbraking ability. They shouldn't be able to plow through 20mm rounds (in other scenes, 20mm A2A cannon fire brings them down)- but its an anime. An anime based on a book, but still not the most authoritative portrayal out there. Rolling Eyes

Yukikaze is the kind of show where it's best to just skip to the parts where stuff blows up.

Quote:

All you need is a 130K lb thrust rocket strapped to your Super Saber!

I'd love to see that on a Raptor! Very Happy

Thanks for the replies guys!

count_to_10 wrote:

The negative G pushover around 2:30 probably would have killed the pilots, unless I'm mistaken.

A doctor pulled 14 negative G's on a rocket sled in the 60's. Not impossible! Shocked

Forum: General F-22A Raptor forum

Is this possible?