HVAR recoil

[Yo-Yo]

Yes, the rocket fuel burns into a hot gas, which is shaped by the rocket body into a rearward moving stream. The reaction to this is that the rocket is propelled forwards. At no point in this equation does the rocket push backward on the wing of the plane.

 

What about the moment when this stream hits to the wing and launcher? And what about the video I posted in #18? At least 2 tonns of jeep rocks very well.

Edited October 7, 2014 by Yo-Yo

[Tucano_uy]

Come on Yo-Yo, stop looking for excuses and start coding, we don't want recoil from rockets!! :smilewink: :lol:

[Yo-Yo]

Come on Yo-Yo, stop looking for excuses and start coding, we don't want recoil from rockets!! :smilewink: :lol:

 

Don't you mix me with a waiter?

Edited October 7, 2014 by Yo-Yo

[KLR Rico]

What about the moment when this stream hits to the wing and launcher? And what about the video I posted in #18? At least 2 tonns of jeep rocks very well.

 

As it exists right now, it would appear that the wing is presenting a huge amount of drag to the rocket's exhaust stream.

 

Also, the video isn't a similar situation to the rockets because those are morars being fired out of a closed tube, not a rocket hanging freely under a wing. Watch MLRS systems firing on youtube and I think we have something closer to what happens on the P-51 than a mortar.

Edited October 7, 2014 by KLR Rico

[Yo-Yo]

As it exists right now, it would appear that the wing is presenting a huge amount of drag to the rocket's exhaust stream.

 

Also, the video isn't a similar situation to the rockets because those are morars being fired out of a closed tube, not a rocket hanging freely under a wing. Watch MLRS systems firing on youtube and I think we have something closer to what happens on the P-51 than a mortar.

 

Are you kidding? Didn't you see the gas tails BEHIND the tubes and then BEHIND the rockets?

I can say (TOP SECRET!) that if you try to use MORTAR of the caliber you see in the video at the such installation it will be fatal for the installation because of massive recoil. Mortars, starting from 82 mm, use massive pods to dissipate their recoil. Even tank vehicle mounted they fire using the pods.

[Art-J]

Well, maybe this "mortar" comment was not the most fortunate one :D, but I kinda get the point Rico tried to make. We should find some footage with zero-length launcher mechanism (just like on P-51) to try to estimate the recoil. The problem is, I can't think of any similar launchers being used anywhere nowadays!

[flare2000x]

This video might help:

 

 

flare

[Yo-Yo]

This video might help:

 

 

flare

 

What do you want to see in this video? Several degree yawing??

 

I have the better one then.

 

 

But It's not HVAR on the Jeep - less caliber - but the rails are bending.

 

Anyway, I can not tell something certain after this video - too much dust, but it seems to me that rails (without a wing) has less drag than a tube type launcher.

[Maverick-X]

In the video the rockets are fired in pairs. So they cancle each others recoil out, if it exists...

[Tucano_uy]

[Wolf Rider]

Crikey... quite a few posts have gone missing :cry:

[ShuRugal]

Are you kidding? Didn't you see the gas tails BEHIND the tubes and then BEHIND the rockets?

I can say (TOP SECRET!) that if you try to use MORTAR of the caliber you see in the video at the such installation it will be fatal for the installation because of massive recoil. Mortars, starting from 82 mm, use massive pods to dissipate their recoil. Even tank vehicle mounted they fire using the pods.

 

watching that video, i see two different weapon systems being fired from pickup trucks.

 

The first was rockets from a 6-tube launcher mounted to the bed of a light duty pickup. The second was a meavier pickup (looked like it may have been a 1-ton, extended cab) had a single-tube weapon with the back end down inside the bed, which rather strongly suggests mortar to me.

 

Of the two, the light pickup with the rockets didn't even flinch, only the one with the apparant mortar bounced and rocket around.

[Holbeach]

The P 51D manual states, when dealing with asymmetric effect of jammed guns and HVAR rockets,

 

"Rockets have NO recoil and may be used from light aircraft without damage".

 

There should be no effect on the airframe, such as you would get from a gun.

[Captain Orso]

Title From Crossbow to H-bomb

A Midland book, MB 161

Issue 161 of Midland book

Authors Bernard Brodie, Fawn McKay Brodie

Edition illustrated, revised

Publisher Indiana University Press, 1973

ISBN 0253201616, 9780253201614

Length 320 pages

 

Page 228

 

 

Is this going to be fixed?

[msalama]

In theory, rockets have no recoil if the launcher tube is open at both ends. That much is true. But there's some stiction/friction between the tube and the rocket still, which must be overcome if the rocket is to fly anywhere. And thus a certain amount of recoil will STILL be present even with an open launcher, no?

[Flagrum]

In theory, rockets have no recoil if the launcher tube is open at both ends. That much is true. But there's some stiction/friction between the tube and the rocket still, which must be overcome if the rocket is to fly anywhere. And thus a certain amount of recoil will STILL be present even with an open launcher, no?

 

Friction would not cause recoil. Instead the rocket would rather pull the aircraft forward.

[msalama]

Instead the rocket would rather pull the aircraft forward.

 

Hmmm... indeed. Still, there's bound to be a reaction when the rocket departs as the aircraft "snaps back" to its natural velocity.

[VT-51_Skeetr]

I flew Helicopter Gunships in Vietnam and was an armament officer as a side duty. I only have experience with the 2.75 inch rockets but a lot. In normal operation there was a slight pull as the motor had to build thrust before leaving the tube. It was a largish spring device sort of like a cartridge extractor. In the "Bravo" and "Charlie" model guns (with 7 shot pods) we set the intervalometers to fire the right side rockets first then we'd be firing one at a time out of the left. The aircraft would be pulled forward by the rocket before it left the tube. With Cobras and old gunships (Hogs) with the larger (19 shot) pods we would fire in pairs and the ship would generally hold still. I could babble on endlessly but it was an art and took a lot of practice. I made some lucky shots but basically sucked then and still do. :)

[Captain Orso]

In theory, rockets have no recoil if the launcher tube is open at both ends. That much is true. But there's some stiction/friction between the tube and the rocket still, which must be overcome if the rocket is to fly anywhere. And thus a certain amount of recoil will STILL be present even with an open launcher, no?

 

The rockets are not in tubes.

 

If there were that much friction, there would be a great danger of them jamming.

 

Nobody has been able to produce any evidence of there being any kind of recoil from firing the HVAR's.

 

There are several documents stating that there is no recoil, including the official pilot's manual.

[Captain Orso]

Hmmm... indeed. Still, there's bound to be a reaction when the rocket departs as the aircraft "snaps back" to its natural velocity.

 

The rockets are not pulling the aircraft, so there is no "snaps back". The argument for recoil/pulling is without evidence and only apologetics.

[Captain Orso]

I flew Helicopter Gunships in Vietnam and was an armament officer as a side duty. I only have experience with the 2.75 inch rockets but a lot. In normal operation there was a slight pull as the motor had to build thrust before leaving the tube. It was a largish spring device sort of like a cartridge extractor. In the "Bravo" and "Charlie" model guns (with 7 shot pods) we set the intervalometers to fire the right side rockets first then we'd be firing one at a time out of the left. The aircraft would be pulled forward by the rocket before it left the tube. With Cobras and old gunships (Hogs) with the larger (19 shot) pods we would fire in pairs and the ship would generally hold still. I could babble on endlessly but it was an art and took a lot of practice. I made some lucky shots but basically sucked then and still do. :)

 

Those are some interesting first-hand experiences :thumbup: Still, the HVAR is a different weapon firing from a different platform

 

[Yo-Yo]

Those are some interesting first-hand experiences :thumbup: Still, the HVAR is a different weapon firing from a different platform

 

 

I think the statement that "rockets have no recoil" was used to compare to conventional cannon with the same or comparable caliber.

But if any part of the launcher interacts with a high-speed jet stream, it will encounter dynamic pressure action of it - for short time but it will. The impulse of this interaction depends on the rocket thrust and the area and the lenght of the launcher.

Large block of tubes like modern Russian (for S-5 and S-8) and USA Hydra will definetely encounter sufficient interaction either the jet nozzle is inside the tube or just in front of it.

 

Small launchers, like in the Mustang will have less recoil effect, so what is strange if a heavy rocket has the same recoil as a 46 g bullet?

[VT-51_Skeetr]

I agree. I doubt that the rockets held openly under the wings would have the same effect. There would be something holding them back however. No rocket motor generates full thrust instantly. The 2.75" I used needed to build up thrust so that they accelerate quickly. They were also more heaviest towards the warhead. The motor section is lighter and most of the length. That is why being in trim was critical. The rocket will weather-vane into the relative wind until it builds some velocity. So there would be some hold-back mechanism but I'd guess the effect wouldn't be much more than the back blast pushing the other way a moment later. I was told by younger pilots that the new motors generate high thrust more quickly now (shooting at a hover no doubt requires it) but you still wouldn't want them to slide right off easily.

[msalama]

and only apologetics.

 

From whose part, mine? Nah, just interested in the phenomenon, that's all.

[msalama]

The rockets are not in tubes.

 

Indeed not, was thinking about the Huey pods when I wrote that, my bad.