Ka-50 Unguided Rockets Firing Possible Bug! - Page 6 - ED Forums
 


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Old 12-13-2019, 12:56 PM   #51
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Unfortunately I havent seen one of my pals in years, he flew Cobra in Vietnam and should know this. If I can get a hold of him, I will squeeze that out of him.

The helicopter will change it's attitude, that is clear. No action goes without a counter reaction, be it thrust being deflected by some metal part of the tube or airframe, or the loss in weight, or both, I dunno, but I know it will surely not stay as it was. The faster you move the harder it gets to disturb the moving mass, so this will change with speed, I just dunno how much and if it is relevant for a specific helicopter. I could imagine that the deflected thrust might disturb the airframe, launching multiple ones then even more. Looking at thrust nozzles, those are quite small, I could imagine that.

I do know that the cobra needed FULL rudder on take-off until it had quite some forward speed, that he told me Maybe worth a note.

There is another guy I know who flew choppers in Nam, the small Special Forces one, but his civ job at RAB ended and he's likely back in the US. I might get a hold of him.

* Wrote an email to my friend, I hope he is still with us. Waiting for an answer.
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Old 12-13-2019, 01:21 PM   #52
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Seems like we agree to disagree to some extent. Fine with me. Indeed it would be good to get imput from a subject matter expert, pilot or engineer or something. Just so difficult to determine validity if just a comment from someone here at the forum claiming to be one of these.
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Old 12-13-2019, 01:30 PM   #53
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Here's the answer from my fellow friend Larry, a veteran OH-6 Vietnam Pilot:

****************************************************************************
There is no change in pitch for the rockets but there is of course a weight change depending on how many you launch at one time. Most of the time you shoot in pairs but you can do many more or just salvo the load. The mini-gun will cause a change in attitude opposite the direction of target but small for the gunships. The change is a lot in the smaller OH -6 and will throw you off target if not anticipated.
The new gun ships use smart weapons so if locked on it will go find the target much easier than aiming the aircraft at the target as us older pilots did.
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Old 12-13-2019, 02:18 PM   #54
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Old 12-14-2019, 12:09 AM   #55
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Hi guys,

It's a pure SAS question. Already noticed that it too happened when rocket tubes were empty and that I pushed the trigger.

The workaround is to fire with flight director engaged.
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Old 12-14-2019, 04:47 AM   #56
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Hi Dimitriov -
Thanks, (but also I think that was worked out a while ago).

The question is - what is the SAS accounting for ?

OH-6 is a small aircraft, but so is the Hydra a small rocket - less than 4 kg, vs 11.4 kg for an S-8. Even firing Hydra in pairs might not produce much effect - very little weight change, very little exhaust gasses.

The fact that the Ka-50 SAS is designed to compensate for some thing (& Kamov were involved in the development of the implementation we have in DCS) means there must be something to compensate for.

I've posted videos showing both yaw and pitch from firing rockets and missiles.

The yaw must logically be a reaction against the exhaust gasses from the rocket or additional drag / lift / loss of lift from the rotor as it suddenly finds itself in a stream of gas moving at high speed in the opposite direction to the rocket.

Which is actually a culprit we haven't discussed.
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Old 12-14-2019, 05:25 AM   #57
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Quote:
Originally Posted by Weta43 View Post
Hi Dimitriov -
Thanks, (but also I think that was worked out a while ago).

The question is - what is the SAS accounting for ?

OH-6 is a small aircraft, but so is the Hydra a small rocket - less than 4 kg, vs 11.4 kg for an S-8. Even firing Hydra in pairs might not produce much effect - very little weight change, very little exhaust gasses.

The fact that the Ka-50 SAS is designed to compensate for some thing (& Kamov were involved in the development of the implementation we have in DCS) means there must be something to compensate for.

I've posted videos showing both yaw and pitch from firing rockets and missiles.

The yaw must logically be a reaction against the exhaust gasses from the rocket or additional drag / lift / loss of lift from the rotor as it suddenly finds itself in a stream of gas moving at high speed in the opposite direction to the rocket.

Which is actually a culprit we haven't discussed.
It's hard to tell if there is any real force in those video's. You can clearly see in this one there is no movement at all when firing rockets at speed from one side. I'm not saying there is no force here, it's just straight back against the round tube exiting the rear. Trying to force the nose down (pendulum) under the rotor blades.

I just find it hard that these rockets could do that against a very large moving spinning disk above.

The only thing I can think of is that these FCS systems could be needed with the larger S-13 or Vikhr missiles when Hovering or moving at very slow rate.

Vikhr missiles especially as they are generally fired when slow or hovering Plus the angle they can go to.

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Old 12-14-2019, 10:23 AM   #58
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there's enough turbulence caused by the rocket motors to flame out the engine - that should rock the aircraft
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Old 12-15-2019, 02:05 PM   #59
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Not that much I guess.

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Old 12-16-2019, 12:06 AM   #60
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Quote:
Originally Posted by David OC View Post
Not that much I guess.
Firing individual little 4kg Hydra rockets with the SAS turned on - would you expect to see anything ?
All it proves is the AH-64 SAS can compensate. (We think the Ka-50 SAS should do the same - it just isn't.)



Sure looks like a lot here
Firing a salvo of 11.5 kg S-8 from a hover @ 1:26 causes engine failure and a crash. Apparently the change in inlet pressure caused by the exhausts causes a flameout:
Quote:
Originally Posted by S.E.Bulba View Post





There is a minimum launch speed for S-8 of 100 km/h for just that reason.
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Last edited by Weta43; 12-16-2019 at 12:17 AM.
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