Part 1 - Hovering in Ground Effect

So, this is not a course per se. More a set of notes about my experience of learning to fly RC Helicopters.

The Heli I am trying to learn to fly on is a little GWS Mini-Dragonfly fixed pitch electric heli. Apparently learning on these is tricky as they are quite a bit less stable than larger copters. On the plus side they are of course cheaper. Some essential modifications you should do if you have a little fixed pitch electric heli is get some superskids - they aren't cheap, but your heli will be able to withstand much harsher landings and you will actually have a chance to learn.

Get yourself a 2s LiPo (depending on your heli - 2s was right for mine). Also, think about adding some weight to the head of your heli. Some extra weights on the end of the paddles are a good way to go, just make sure you balance them. Having this extra angular momentum in main rotors will help steady your main rotor speed, a bit like a heavy flywheel stabilises an engine.

So, I started by reading through and doing Radd's School of Rotary Flight Course and suggest you do the same.

I then tried a flight or two at the field on days that were too windy, and also got myself into trouble by trying to punch up (quick high throttle) to get my heli out of ground effect. Problem with punching up as a novice is that you get a broken nose (that's the heli, not you, unless you forgot to duck). This is mainly cause by the time you have finished punching up the heli is basically out of control, and your chances of getting her into a steady hover from there are pretty close to buckley's. So, I would say skip punching up and crashing your heli - here's my theory - if you can hover in ground effect, you can hover anywhere.

What's ground effect? As it applies to helicopters it is effectively the air that you have just pushed down rising back up and providing additional lift. However it's effects on the helicopter are inconsistent and hence the main thing it does is makes the helicopter unstable. Helicopters in ground effect are quite challenging to hover.

Hang on - didn't I just say we were going to hover in ground effect? Am I mad (sorry my writing style appears to have been overly influenced by RADD)? No. In a helicopter, unlike an airplane, being close to the ground is a good thing.

In a helicopter, unlike an airplane, being close to the ground is a good thing.

In a helicopter, unlike an airplane, being close to the ground is a good thing.

Why would I say that? If you've flown fixed wing for a while then you know this little secret - planes basically fly themselves. If you can get the wings back to level, and keep them pointed approximately level you can basiscally recover from anything. And you also know that given enough altitude a trainer almost completely corrects itself. Helis are not like that at all. They get unsettled you have to fix them, and unlike a plane which doesn't tend to get worse (excluding the ground coming closer) a heli that starts to go just keeps on going until either you fix it (effectively impossible given your current skill level) or after transferring a sufficient amount of potential energy into kinetic energy strikes the ground.

In a heli altitude, rather than giving you time to fix things up, gives you time to get into trouble. With a fixed pitch electric heli with superskids if you keep within 2 feet of the ground (so the tops of your legs) you basically cannot damage it provided that as soon as you start to lose her you close the throttle and let her come down as she is.

So, using say a 2.5 x 2.5 metre box (8 ft x 8 ft for US visitors) try and get your heli up and hover in this box, at less than waist high. Remember what you learnt with RADD. Spool up slowly, let the energy come onto the blades, hold the heli steady as she gets ligth on the skids and then very very slowly add power until you are free of the ground. At 2 inches the ground effect is horrendous and keeping the heli steady will be a massive effort, but close that throttle and you are instantly safe. As long as you can hold the heli steady keep on flying her. If she comes above the tops of your legs, or passes outside the box just close the throttle and let her come down.

By keeping her in a tight box, and never letting her get a lot of altitude, and closing the throttle as soon as she gets unsettled we are preventing her from getting so out of control that she will damage herself.

Do that for a battery or two I guess, until you can basically keep her in a one metre square box (3ft x 3ft) for at least 30 seconds.

Now - caues I'm not there yet I can see one possible downside to this approach. You will find, as RADD trained you that hovering at this height will probably need a considerable amount of right cyclic roll as the heli trys to fall off the column of air from ground effect. Just be aware of it, I don't think it will be a problem once we start to go higher.