Started to roll out of control after shooting rockets?

[Frag]

Hi guys,

 

something weird happened to me twice and I thought about asking here since I was not able to figure it out.

 

Twice this week, the Mi-24 started to ROLL on itself like crazy while starting a rocket attack. The chopper get out of control and I cannot get it back (to finally crash).

 

Any hints of what could happen? Next time I will keep the track and post it here. Wonder if its a bug or something I am missing. Just checking here if someone would have a hunch about what it happening...

[FoxTwo]

How fast were you going? Were you descending?

 

Don't exceed 350 kph in the airframe or you will suffer a retreating blade stall.

[S. Low]

It’s almost certainly a retreating blade stall. Cruise speed is 250, I think max speed is 270, and generally you’ll roll over in a retreating blade stall after 335. Keep an eye on the speed

[JIMJAM]

Not sure but I doubt rbs is that sudden, hard to get out of and deadly.

These helis in wartime were flown hard and fast and I would imagine creeping into those speeds and a 100% guarantee the heli would roll over or pitch up dramatically is the last thing on a pilots mind when AAA, rocket launchers and missiles are flying around 

[Cathnan]

It is really easy to get into rbs in this thing. Happened to me multiple times. I usually start rolling in at 250kph and end up at 350 before I realize it because I'm focused on the target. You'll start noticing the signs eventually and if you're quick it's not too hard to recover. But if you don't notice before you rolled past 30° you're almost certainly gone. And yes, it does happen rather suddenly in the Hind. At least in this sim, but iirc that is rather accurate.

[BeastyBaiter]

Retreating blade stall goes into full effect at around 350kph. This is the absolute never exceed speed and is based on true airspeed, so higher up it will be a lower indicated airspeed. 330 kph seems reasonably safe, I try to treat that as the max speed to avoid crossing. Beyond that it starts getting dangerous fast. Getting to that speed during an attack run is very easy if in a shallow dive.

[YoYo]

5 hours ago, Frag said:

Hi guys,

 

something weird happened to me twice and I thought about asking here since I was not able to figure it out.

 

Twice this week, the Mi-24 started to ROLL on itself like crazy while starting a rocket attack. The chopper get out of control and I cannot get it back (to finally crash).

 

Any hints of what could happen? Next time I will keep the track and post it here. Wonder if its a bug or something I am missing. Just checking here if someone would have a hunch about what it happening...

 

Here too much speed is your enemy

[Frag]

You guys were right. I was able to reproduce it. Sorry for my ignorance on this!

 

Indeed, diving for a rocket run will easily throw you at that speed if you are not careful.

 

Thanks for your help guys!

[YoYo]

55 minutes ago, Frag said:

You guys were right. I was able to reproduce it. Sorry for my ignorance on this!

 

Indeed, diving for a rocket run will easily throw you at that speed if you are not careful.

 

Thanks for your help guys!

 

What I noticed the best way on the first symptoms of this falling (when they come out) is to pull the stick (cyclic) on yourself by 30%, dont touch collective handle.

Edited June 22, 2021 by YoYo

[S. Low]

Lower collective and pitch up to recover from rtb.

[YoYo]

1 minute ago, S. Low said:

Lower collective and pitch up to recover from rtb.

 

This will only increase the falling and it gets worse. Only pitch but if it works for you use it.

[S. Low]

I'm not a rocket scientist, just know that I purposely sped up to about 350 and when the aircraft rolled over to the right, I slowly lowered collective and pitched up and I recovered immediately. I read this somewhere as a recovery method. *shrug*

 

[MIghtymoo]

8 hours ago, S. Low said:

I'm not a rocket scientist, just know that I purposely sped up to about 350 and when the aircraft rolled over to the right, I slowly lowered collective and pitched up and I recovered immediately. I read this somewhere as a recovery method. *shrug*

 

Agree. Works great.

[Blackeye]

15 hours ago, YoYo said:

 

This will only increase the falling and it gets worse. Only pitch but if it works for you use it.

 

No.

 

Lowering the collective will reduce the AoA of the blades thus decreasing the area where the blades are stalling and giving you back control - it is usually the first step of recovering from RBS as you may not be able to recover if you do not lower the collective first.

 

 

Quote

I'm not a rocket scientist, just know that I purposely sped up to about 350 and when the aircraft rolled over to the right, I slowly lowered collective and pitched up and I recovered immediately. I read this somewhere as a recovery method. *shrug*

 

That's the way to do it. See for example https://www.skybrary.aero/index.php/Retreating_Blade_Stall#Stall_Recovery:

 

• Reducing collective pitch. This reduces the angle of attack in the plane of rotation and should be done first.
• Gently Applying aft cyclic to slow the aircraft. Application of aft cyclic without a reduction in collective pitch will only worsen the stall. An attempt to roll away from the stall can also make the situation worse as it places even higher demand on the stalled blade.

 

Edited June 23, 2021 by Blackeye

[yngvef]

I would highly recommend checking out CasmoTV on Youtube. He has some excellent helicopter tutorials, including a very recent one about unguided weapons employment called "DCS Hind Tutorial #3- Unguided Weapons Employment- The Bump".

 

Him being a real helicopter pilot with plenty of real world experience from Apaches and Kiowas, he's my go-to guy for learning about rotary wing stuff.

 

In the video I mentioned, he describes using a maneuver called "the bump" where you fly towards your target at low altitude and high speed and then pull up (30 degrees nose high) and drop the speed as well as gain altitude. Then as speed goes down between 150-100 kph in the Hind, you pitch down again and get a very nice high angle on the target for an easy attack with guns or rockets.

 

This makes it much easier to prevent overspeeding as you are fairly slow at the top of the climb. I used to fly at medium height and try to dive from it, but as you are already going at maybe 250kph, it is very risky.

 

Check out his channel, he deserves more attention as it is very good and informative content.

Edited June 23, 2021 by yngvef

[Frag]

38 minutes ago, yngvef said:

I would highly recommend checking out CasmoTV on Youtube. He has some excellent helicopter tutorials, including a very recent one about unguided weapons employment called "DCS Hind Tutorial #3- Unguided Weapons Employment- The Bump".

 

Him being a real helicopter pilot with plenty of real world experience from Apaches and Kiowas, he's my go-to guy for learning about rotary wing stuff.

 

In the video I mentioned, he describes using a maneuver called "the bump" where you fly towards your target at low altitude and high speed and then pull up (30 degrees nose high) and drop the speed as well as gain altitude. Then as speed goes down between 150-100 kph in the Hind, you pitch down again and get a very nice high angle on the target for an easy attack with guns or rockets.

 

This makes it much easier to prevent overspeeding as you are fairly slow at the top of the climb. I used to fly at medium height and try to dive from it, but as you are already going at maybe 250kph, it is very risky.

 

Check out his channel, he deserves more attention as it is very good and informative content.

 

 

This is the video yngvef is talking about. This thing is GOLD. I thought I was the only one thinking that the rocket blast effect was too weak. He also mentioned this, so that made my day.

 

 

 

Edited June 23, 2021 by Frag

[yngvef]

That's the one