how does a missile work? (1 Viewer)

[Cam S]

You're totally right, Keith. Jet fuel, as far as I know, doesn't burn except under remarkable temperatures. I would be somewhat surprised if slamming it into a mountain would cause it to explode, even with plenty of sparks.

Uh, they don't explode? Havn't you ever seen the videos of air shows and other plane crashes where the planes fall to the ground at relatively low speeds and blow up in a huge ball of flames. I've yet to see a plane crash where there wasn't a huge ball's of flame except if it was going VERY VERY slow.

 

[Holadem]

You're totally right, Keith. Jet fuel, as far as I know, doesn't burn except under remarkable temperatures. I would be somewhat surprised if slamming it into a mountain would cause it to explode, even with plenty of sparks.

This is a very strange statement in this day and age :frowning:
--
Holadem

 

[Michael Marklund]

Danny,
Sorry for not elaborating my reply. Yes, a missile generates more g's in a turn. However, as you correctly added, velocity increases it's turning radius to be greater than a fighter's (again, provided the fighter has sufficient airspeed to turn tight/fast.) What I should have said was that with a missile's velocity being so great (mach 2,3,4+) anything over a 4g's generated in a turn makes the missile's turning radius greater than that of the fighter's.

As to the IRIS-T: it's in testing. First drone nailed March 2002. With potential production/shipping around end of year. That may change things. For now though, it's look and duck.


Respectfully,
MM

p.s.-other Hollywood BS: Tom Cruise's slam on the brakes stunt to get the other plane to fly past was not new to the guys at Top Gun. That was one of the selling points Grumman pitched the Navy to get them to buy the plane.

 

[felix_suwarno]

thanks holadem. i actually have read all about semi active radar etc etc 10 years ago. i have forgotten most of them!

well, in my response :

"my response was that it doesnt make sense to perform tighter turns because the missiles ( any ground or air to air missiles ) fly sooo god damn fast."

what i meant was that a missile cannot do tighter turns. not the plane.

the discussion becomes more interesting! i used to like jetfighters etc etc until i started playing sega genesis...

btw my conclusion is that "behind enemy lines" doesnt make sense. pure hollywood.

 

[felix_suwarno]

"Uh, they don't explode? Havn't you ever seen the videos of air shows and other plane crashes where the planes fall to the ground at relatively low speeds and blow up in a huge ball of flames. I've yet to see a plane crash where there wasn't a huge ball's of flame except if it was going VERY VERY slow. "

planes explode because ( i think ) the engines were still turned on, they were still burning the fuel. dropped fuel tanks...they are completely different story. imagine filling gasoline into a bottle, and throw it away as far as you can. do you expect them to explode?

 

[Cam S]

Felix, how fast could you throw a bottle of high octane Nav gas? maybe 20 mph or a little more. Just a little slower than the 200+mph planes are travelling at, and that's still considered slow. Add to the speed the weight of the plane or fuel tanks and that's a lot of momentum.

I've seen videos of planes being tested with a special gas that was supposed to keep the fuel from igniting, but even it didn't work, still went up in a ball of flame.

 

[Michael*K]

i used to like jetfighters etc etc until i started playing sega genesis...

OK, I'll bite. Why pray tell did you lose interest in fighter aircraft with the advent of the now ancient Sega Genesis system?

 

[Philip_G]

planes explode because ( i think ) the engines were still turned on, they were still burning the fuel. dropped fuel tanks...they are completely different story. imagine filling gasoline into a bottle, and throw it away as far as you can. do you expect them to explode?

Jet A is basically kerosene. It burns pretty hot, but on impact in a crash there are lots of hot things to ignite it, and fuel sloshing everywhere. I'm not sure I'd call it an explosion, more of a large fireball.

Off topic but a few years ago they tested an additive for jet a, that would make it congeal if agitated, as in an accident to reduce fire casualties, they wrecked a (B-707?) remotely with test dummies on board and a full load of fuel + additive, it failed. It was just a milky white additive, not really a special fuel (the one I saw anyway, the crash video is probably available on the net, seen it a million times in various classes)

 

[felix_suwarno]

michael*k

haaa. that is an interesting question. well, i dont mind sharing a little bit of my life in this forum, so here it goes.

as a kid ( i am 26 now ), i loved all kinds of jetfighters, especially 1960 and up products. i was born in a south east asian country ( pure chinese, btw ), so when i was about 14 years old i realized it would be impossible for me to pursue education in aerospace engineering. i mean, there is not such a thing in my country ( indonesia ).

and somehow i saw thunderforce3 ( made by technosoft, 1990 ) on megadrive ( genesis counterpart ). it changed my life, i started to dig the world of videogames even deeper. before that, i only played f19 stealth fighter by microprose!

to me, the world of videogames is just more interesting. to create a game you need to be really creative with wild imagination. while on aerospace engineering, i think you need to be really smart. i am not smart, but i do have talent on computer graphics ( thats why i am a comp graph grad student at depaul univ, chicago now ).

i still have interest with fighter aircraft, but... i dunno. i stopped following the technology since many many years ago. the newest thing from russia that i know at this point is sukhoi s37 berkut. anything after that, i have no idea.

 

[felix_suwarno]

cam, i didnt know that fuel could ignite fire if the tank is dropped in high speed. that is new to me! thanks

 

[Bruce Hedtke]

Fuel needs two things to ignite: oxygen and an ignition source. The ignition source would come from the fact that metal fuel cylinders colliding with the earth at a high rate of speed would produce sparks.

Bruce

 

[Edwin-S]

This is kind of a side note, but how did the pilots know the missles had locked on to them? What about the missle guidance system is detectable by the jet?
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Missile launchers for anti-aircraft missiles have ground based Radar for aircraft detection. The pilots are probably not so much detecting the missile locking on; they are detecting the lock from the ground based radar on the launcher. IIRC heat seekers would be guided by to the general area of the aircraft by radar and then the heat seeking head takes over once it picks up a signature.

The Wild Weasel program in Vietnam used F-105 "Thuds" to actually draw SAM fire. Once the SAMs were launched the "Thuds" would fire an anti-radar missile which would lock on and follow the radar signal being put out by the SAM launcher. The SAM operators then had a choice, shut off the radar which would cause the missiles to lose their lock or risk being destroyed.

 

[felix_suwarno]

"The Wild Weasel program in Vietnam used F-105 "Thuds" to actually draw SAM fire. Once the SAMs were launched the "Thuds" would fire an anti-radar missile which would lock on and follow the radar signal being put out by the SAM launcher. The SAM operators then had a choice, shut off the radar which would cause the missiles to lose their lock or risk being destroyed. "

whooaaa!!! that is cool!! i hope they do a movie about it!

btw, f-105? i thought the codename was "thunderchief". the one that looks like rocket with wings?

 

[Keith Mickunas]

Felix, in Flight of the Intruder they demonstrate this with A-6 Intruders. The F4 Phantom eventually took over the role of Wild Weasel for the Air Force and served in that capacity through the Gulf War if I remember correctly. A while back I read that development was being done on a variation of the HARM missile (the current anti-radar missile) that would allow it to loiter in an area if the ground radar was shut down and wait for it to come back on. I don't know the status of that missile.

I've also heard that in some cases if a ground radar is painting an aircraft that they turn directly into the radar which can make a lock difficult.

 

[felix_suwarno]

keith, thanks for that. i will rent the movie.

but :
"I've also heard that in some cases if a ground radar is painting an aircraft that they turn directly into the radar which can make a lock difficult. "

i thought it would make it easy for the radars to lock the target. because, even though the plane was made of "anti radar" materials, the engines were not. in that position the engines would be exposed. well, i know this stuff from playing f19 simulator. it might not be a correct theory though, since the game was just... a game. it wasnt a hardcore flight sim such as f16 falcon game on pc.

 

[Keith Mickunas]

Felix, turn into, by that I mean directly pointing at and dive at it. I think by approaching quickly at the radar it has trouble locking on due to the speed or something. Turning away would be bad because then it'd have a lot of time for the missile to achieve its lock since it can travel faster but in that case have a good bit of time to home in on the airplane.

Also, if I remember F-19 correctly, and its been a long, long time since I played it, certain types of radar you wanted to be perpendicular to, others you wanted to point at. By facing the radar, the plane would have a lower cross section for the radar to detect.

 

[Grant B]

In the 60s a 1st stage nozzle stuck hard over on a Polaris missile. It stayed together and did a 360 before Range Safety pressed the destruct button.
Thats when it was realized it was way over built.
Talking about a generic cruise missile and trying to figure out it's characteristics is kind of impossible.
I believe Janes is on the web and thats the bible on things that go boom. Try them ...thats where the soviets went when they needed data (I just checked and thay dont give it away...sorry)

 

[Holadem]

I've also heard that in some cases if a ground radar is painting an aircraft that they turn directly into the radar which can make a lock difficult.

It has to do with radar cross section. As you know, radar work by reflecting waves of the target. The less surface you expose, the lower the amount of reflections and the fainter the echo. There is obviously less exposure by presenting your nose than your flank.

On the other hand, if you are being painted by a doppler radar, you might have better chances exposing your side: This kind of radar works by detecting the frequency shifts in the reflections off the target. These frequency shifts are cause by the relative velocity of the aircraft from the radar. The faster away or toward the radar the aircraft is moving, the better it is picked up. Exposing your side means you are traveling with the radar on your side, which reduces your relative speed, minimizing the doppler shift. YOu are essentially immobile, making it significantly harder for the radar to make anything out.

--
Holadem

 

[Don_Houle]

I haven't seen this movie, but I remember seeing some scenes of the "missile chase" - I also remember laughing when I saw this - although it looked pretty cool. I've always had an interest in military aviation. I've spent a LOT of hours "playing" some of the better combat flight simulations and doing a LOT of reading.

BTW, some of these newer PC "games" are quickly approaching the reality levels (in terms of avionics, flight characteristics, pilot load, and overall performance).

That said, here's my two cents:

Heat seeking missiles (like the AIM-9 Sidewinder which has a speed of about mach 2.5) home in on the infrared signature of the target (mainly, the engines, but also other parts of the airframe). These missiles are relatively "dumb" and have been known to be fooled by heat sources other than their targets - the sun, flares, even ground based heat sources. If the AIM-9 loses it's lock on an IR source, it's possible to regain a lock if a suitable IR source is "available" (this could be any other aircraft!) - but, due to the speed the missile travels, it's unlikely. The launch of these types of passive guidance missiles is not detectable by aircraft systems. Pilots usually rely on wingmen or spotters to warn them.

Once the missile has been spotted, the typical procedure is to reduce thrust in order to reduce the aircraft's IR signature. A series of flares are released to confuse the missile and then a series of manuvers is then undertaken to force the missile into a poor position. This typically entails placing the missile at the 3 or 9 oclock positions and then turning INTO the missile.

Most radar guided air to air missiles (like the AIM-120 AMRAAM and the AIM-7 Sparrow) are incapable of reaquiring their target if it loses a lock. However, some radar guided AA missiles are rely on the launching plane's own radar for a certain amount of time. It then switches over to it's own, less powerful radar, to guide to the target. Pilots can be alerted to the launch of a radar guided missile by their Radar Warning System which detects any threats and displays their locations.

Once the missile has been spotted, the typical procedure is to increase thrust in preparation for the defensive manuvers to come. A series of chaff is released to confuse the missile and then defensive manuvers are undertaken to force the missile into a poor position. This typically entails placing the missile at the 3 or 9 oclock positions and, when it's close enough, turning INTO the missile.

Turning into the missile seems counterintuitive, but it works like this: IR and radar guided missiles, in general, both compute the shortest possible trajectory to their targets. The onboard computers add in a certain amount of lead based on the distance to the target and the speed of the target and the missile. The goal of the turn-in is to force the missile, with it's higher speed (and larger turn radius) to overshoot the target.

I could go on and on about this, but I won't. There is plenty of good info on the Internet regarding this subject, so you can find it for yourself, if you're interested enough!!

Peace....

 

[Dan Lindley]

Hi Felix,

glad the Weasel thing is interesting. We (and the Brits) do it to Iraq on a weekly-monthly basis. When we attack AD sites, it means they painted our planes with radar, and we attack back with HARM missiles (usually).

So this is a 30+ year old game. Wouldn't be surprised if the equivalent is as old as aviation (taking out blimps in WWI??).

Not sure the Weasel is still the term since F-4s are no longer used as the 'Weasel craft'. Anyone chime in on this?

Dan

As for the SR-71 phase out, I'm pretty sure it was budgeteers looking at satellites and saying 'that'll do'. my view: no it won't. Also, why were the battleships phased in and then back out: simple: money. Huge crews. My view: get them back. Everything else in the inventory is made of tin foil compared to them.