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Helicopters wobbly

Helicopter flying is completely different from flying a fixed-wing aircraft and thus requires different skills.

Helicopters wobbly

Postby Flyboy » Tue Jul 06, 2010 2:53 am

I'm having problems with a couple of the helicopters... to start off, I'm new to helicopters, which means that I'm not at all smooth on the take offs, etc. but I can control them. Except for one problem. The EC135 and BO105 will on occasion start uncontrollably wobbling in all directions. When this happens, I have to push the stick full to the left to keep the heli somewhat level, and I also have to give a hard twist on the stick to keep it from spinning. When this happens I also seem to lose lift. Sometimes it happens when I've been airborn for some time, and sometimes it happens as soon as I lift off. It will usually stop after half a minute or so. I'm running Flight Gear v2.0 on Fedora 13. Any chance this could be a bug, or am I doing something wrong? It hasn't been a problem with the Sikorsky 76C++.
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Re: Helicopters wobbly

Postby redneck » Tue Jul 06, 2010 3:10 am

The Sikorsky 76C++ is easily the EASIEST heli to fly to an unrealistic extent. Now, the Bo105 and ec135 are very realistic, so I attribute your problem to pilot error. I'm probably not the best person to try to teach you how to fly a heli (Hint hint HHS and Groucho ;)), but from what I've read, and from my experience, you must make VERY gentle changes in control input to keep them stable. OH! How fast are you flying. If you fly too fast the heli will roll and pitch uncontrollably. I think it is to simulate the structural damage you are about to cause, which isn't actually simulated (yet?).

Let's see, loss of lift. This happens when your RPMs drop. If you have the collective pitch pulled up, are going too fast, and you're pulling up on the cyclic (let's say you accidentally nose-dived) then you should find that the RPMs drop, and you are unable to climb, and then you crash. The trick to get out of that is to carefully reduce collective, NOT TOO MUCH, in order to maintain your RPMs, as you pull on the cyclic. However, if you have nose-dived, your chances of escape are slim.

What else... happens as soon as you lift off. If you try to take off and find the the heli immediately goes into a spin, you have pulled the collective too fast. To recover, slowly reduce the collective while countering the spin with tail rotor force. The heli should eventually stop spinning and become controllable. Be very careful, and avoid lag, since you'll be at a very low altitude when this happens.
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Re: Helicopters wobbly

Postby MD-Terp » Tue Jul 06, 2010 3:23 am

Minor clarification --
redneck wrote:If you fly too fast the heli will roll and pitch uncontrollably. I think it is to simulate the structural damage you are about to cause, which isn't actually simulated (yet?).

It's actually possibly a simulation of retreating blade stall, which happens when the forward motion of the helicopter cancels out the backward motion of the rearward-moving side of the main rotor, causing the blades on that side to stall.
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Re: Helicopters wobbly

Postby Flyboy » Tue Jul 06, 2010 4:41 am

Thanks for the quick reply! At least one of the times when it happened I was flying too fast. Thanks for all the tips, I'll certainly keep them in mind when I'm flying! I'll have to say, the level of detail of the simulation is quite impressive! :P
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