Nasty aerodynamics or a bug?

I don't know what happened, but I got into a unrecoverable roll straight into the ground.

Not sure if it's a bug or not.

Video: [ame]

I started to pull the aircraft up to avoid over speeding, but it seemed to aggravate the situation.

I don't know what happened, but I got into a unrecoverable roll straight into the ground.

 

Not sure if it's a bug or not.

 

Video:

 

I started to pull the aircraft up to avoid over speeding, but it seemed to aggravate the situation.

Like I can see you try to make a roll without speed? Look at the speed needle it's at 0 when you're starting your roll. To make a good roll you must have speed a little pulling to keep altitude during the roll and apply full deflection. Don't forget to move the collective a little down when you are backup.

That looks like an impressive demonstration of retreating blade stall. :D

During the descent, look at the airspeed indicator: at one point, it reaches the limit of the scale. The helicopter is flying so fast that the blades on the retreating side (right side) stall, i.e. they don't generate lift any longer, while the blades on the advancing side still do. The result is an unrecoverable right roll with a strong pitch-up tendency in any chopper where the blades rotate clockwise, like the Gazelle, and that's exactly what the video shows.

TL;DR: Nasty aerodynamics. ;)

The introduction to the misery looked a lot like pilot induced oscillations. I know how hard it is to get any chopper under control in DCS (probably also pretty hard in RL, but never tried that). Just try to be as gentle as possible. Small, tiny inputs. Adjusting your joystick settings in DCS (some curvature, or reduced saturation) can do marvels there. And most of all: Practice, practice, practice, until it clicks. :thumbup:

I guess now that you guys mention it, was just a nasty case of blade stall. The Huey doesn't act this bad, but I guess light choppers act waaay differently.

Really I was just messing around to see how this thing handles. I've rolled it many times before at high airspeeds (And damn it's fun). I guess it doesn't like low speed maneuvers.

I think I've also read somewhere that the Gazelle is not much of a low-speed chopper anyway.

thanks guys :D

Yeah light chopper require light touches. Takes a bit to get used to, but she's worth it.

At 0:22 I believe you could have recovered if you'd immediately dropped collective to zero and pulled back on the cyclic. You were in a nose down attitude at 200 kph, but stable.

By 0:26 your speed exceeded 300kph and you entered RBS in a dive, which I think is unrecoverable.

At 0:22 I believe you could have recovered if you'd immediately dropped collective to zero and pulled back on the cyclic. You were in a nose down attitude at 200 kph, but stable.

 

By 0:26 your speed exceeded 300kph and you entered RBS in a dive, which I think is unrecoverable.

I'm uploading a new video about retreating blade stall, and some recovery procedures.

I'll start a new thread too.

Way to much movement on the controllers.

When sitting on the tarmac with the collective down but the chopper spooled, trim (fine trim not magnetic) to its extremes and these positions will show the extremes of normal flight movements of the stick.

keep the pedals within the new diamond limits.

The remainder of the stick and pedal travel will get you out of the tightest of problems.

That video reminds me that one :)

Probably not connected in any ways but in the end it's quite the same behavior

Hi, this is defenately a retreating bladestall effect. When you look at the speedindicator you hit the 300km/h mark there in your dive very quick. The blades of the SA342M are limited to about 285km/h, which is a number of the manufacturer.

The SA342M is not able to go 300km/h and it is also douptable that she will go 285km/h. The max speed we have as info is about 240 - 260, which implies a save flight.

In an overspeed you will start to roll and eventually die if you do not prevet to recover from your overspeed soon enough or tryy to recover before the overspeed actually occures.

I am not sure how the uh1 would behave, but it is also a different helicopter and a different product, not made by us, so i will not judge if it is correct or not how she behave, cause i also have never attampted to overspeed her.

I try to fly in the limits, always, cause that is how the real deal would be flown too.

I am not sure how the uh1 would behave, but it is also a different helicopter and a different product, not made by us, so i will not judge if it is correct or not how she behave, cause i also have never attampted to overspeed her.

As Belsimtek's UH-1H approaches retreating blade stall, she develops an increasing roll to the left that has to be corrected for using the cyclic.

This is accurate according to the Huey pilot that tested it.

http://forums.eagle.ru/showthread.php?t=118000

I don't know how the Huey responds in a unrecoverable dive but don't expect it'd be a good outcome.