Help needed!

[ThinKat]

I've been flying fixed wing aircraft off and on for some time and I thought I'd try a helicopter. I bought a cheap (£70) Apache from Maplin - it's 4ch and about 15" long. The trouble is I'm having great difficulty flying it.

There are a couple of things that seem to be causing me problems. Firstly the throttle control (mode 2 on the left) gives more power when you push it forward. Pulling it back slows the rotors. Is this normal? It's giving me a lot of trouble because, having been used to fixed wing, I naturally tend to pull the throttle/elevator control back to climb but this requires the opposite. I think this is the main reason I crash all the time. Fortunately the heli seems very robust - most of the rockets and guns have broken off but the basic craft is still OK.

The other thing that is causing trouble is that the aileron doesn't seem to have much effect at all. I'd expected the aileron to cause the heli to bank and drift left or right - as a fixed wing aircraft would do - but it doesn't seem to do this. Any ideas?

TIA.

[trillian]

Hmmm, what mode do you fly fixed-wing in?

In mode 2 for fixed wing the throttle is exactly the same, it is on the left stick and up / forward is opening the throttle.

[Steve]

In mode 2, the right stick is exactly the same as planes - right and left aileron and up an down elevator. The rudder is also the same on the left stick. Depending on how you fly your planes, you may well have to re-chip your brain/thumbs to use the rudder a lot more, as with a heading hold gyro, you cannot bank and yank. If you've been taught to fly planes properly (??) using the rudder (rather than the ailerons) as the primary turning input, then you shouldn't have any problems turning a heli.

The throttle stick is different to an extent. Up throttle does give more engine throttle, but it also gives more pitch on the blades which makes the heli climb. The idea of a heli (full size as well) is to maintain a steady rotor head speed throughout the flight envelope, so when you increase the rotor blade pitch, you increase the load on the engine, therefore more throttle is required. Of course when you lower the throttle stick, the power drops off and you don't have enough blade pitch to keep the heli airborne... hence it crashes.

The next step is to get into throttle and pitch curves which then allow you fly inverted and other stuff.

The biggest problem for plane flyers going over to helis (and yes I suffered this one too years ago) is that when it all goes pear shaped, your natural reaction is to drop the throttle and pull back on the elevator (i.e. pull both sticks down). This is bad news on a heli because you are slamming in towards the ground by dropping off the pitch and removing all power. Again, you need to re-chip yourself to push both sticks forwards when it goes Pete Tong - this increases the lift and pushes the heli into forwards flight. Now the heli is still in the air = not broken, and you'be got time to try and get it back under control.

[Mart61]

As the Apache is a contra heli, you will not have any control over pitch as i understand it. The throttle control, on the left hand stick, will simply speed up or slow down the rotors to generate increased or reduced lift. Pushing the stick away from you increases the speed and vice versa. As such you will have no need to worry about pitch and throttle curves with this model.



As far as aileron is concerned, any aileron input will only cause the heli to drift left or right - side slip if you will. Co-ax helis will not bank as such.

[ThinKat]

Just to clarify, when I said fixed wing I should have said gliders - no power control. So the left stick was elevator and rudder and the right stick was ailerons and flaps. Translating that across to the helicopter the rudder and ailerons are the same, so I'm having no difficulty with these (except that the aileron control doesn't do a lot - Martin said that co-ax helis don't bank much so I guess that's why).

But the heli throttle control is where the glider elevator was, so I'm tending to pull this stick back to go up. This would give a glider up elevator and cause it to gain height (provided it had enough speed). On the heli it cuts the power and causes it to drop. I guess I either have to learn a new technique (at the risk of then crashing the glider) or get a new heli with a programmable radio so that I can reverse the throttle servo. Does this sound sensible or am I nuts?

[brin]

hi mate and welcome to the forum . you might find somewere on your controls either on the front or back under a panel some switches for reversing the controls.

[Mart61]

Now you see why helis are so tricky to fly, and why we call fixed wing aircraft "planks"!



I would guess that, with gliders, you don't use 4 channels?

[Smoothound]

Just to clarify, when I said fixed wing I should have said gliders - no power control. So the left stick was elevator and rudder and the right stick was ailerons and flaps. Translating that across to the helicopter the rudder and ailerons are the same, so I'm having no difficulty with these (except that the aileron control doesn't do a lot - Martin said that co-ax helis don't bank much so I guess that's why).

But the heli throttle control is where the glider elevator was, so I'm tending to pull this stick back to go up. This would give a glider up elevator and cause it to gain height (provided it had enough speed). On the heli it cuts the power and causes it to drop. I guess I either have to learn a new technique (at the risk of then crashing the glider) or get a new heli with a programmable radio so that I can reverse the throttle servo. Does this sound sensible or am I nuts?

All my gliders have aileron and elevator on the same stick the same as a heli. On my left stick I have rudder and on some also butterfly/crow brakes certainly not elevator. Not sure what mode you are flying on gliders but it's not mode 2

[ThinKat]

I would guess that, with gliders, you don't use 4 channels?

Not on all of them, but I have one that has flaps/airbrakes (it's 15' wingspan) and another with flaperons. The way I have it set up on the RC is rudder/elevator on the left and ailerons/flaps on the right. I think I was wrong in calling this mode 2 - it's called mode B in the gliding books.

In any case I need to go back to the drawing board. I now think, with regard to the helicopter, I need the rudder/elevator on the left (where elevator means forward/backward motion) and the aileron/throttle on the right. I think that's the best compromise.

Unfortunately that means that the Apache was a waste of £70 as the RC is not configurable, but I shouldn't have expected anything else at the price.

So the question now is: what R/C equipment, what helicopter and what simulator should I get? I'd guess I'm looking at a Spektrum 6 and something like a TREX250, but should I avoid the contra-rotating ones - as you can tell I know very little.

Thanks for the help so far - it's getting clearer gradually.

[Mart61]

Personally speaking I'd try and learn on Mode 2. There are other modes but 2 is perhaps the most popular. There are ways and means of tinkering with the modes on some radios but, again personally, this is not something I'd wanna do.

I think you will get many replies and opinions as to what heli you should perhaps buy in the future. However I think I'm right in saying that, as a newcomer to helis, the T-rex 250 is perhaps not gonna feature high on the list of recommendations due to stability issues.

[trillian]

But the heli throttle control is where the glider elevator was, so I'm tending to pull this stick back to go up. This would give a glider up elevator and cause it to gain height (provided it had enough speed). On the heli it cuts the power and causes it to drop. I guess I either have to learn a new technique (at the risk of then crashing the glider) or get a new heli with a programmable radio so that I can reverse the throttle servo. Does this sound sensible or am I nuts?

Ah, I see. So yeah that would be pretty weird trying to re-train your left hand that way.

[Steve]

Isn't he describing Mode 1?

Not my style but it works fine for many people on helis.

[Mart61]

Which do you use on the glider, thinkat? It does sound like Mode 1 indeed. I take back what I said about learning on Mode 2 - just buy yourself a Mode 1 Tx (if it's available for your Apache) and go for it.

I've often found that mode 1 radios are cheaper than mode 2 too, at least when they are second hand.

Mode 1:


Mode 2:


Mode 3:


Mode 4:

[ThinKat]

Excellent graphics Martin - that really clarifies the matter. Mode 1 is definitely what will work best for me.

The instructions with this Apache say that the transmitter is either mode 1 or mode 2 but unfortunately their idea of mode 1 is:

left stick: elevator, aileron
right stick: throttle, rudder

which is what you call mode 3. So if I buy another transmitter it probably won't help (it may be that the instructions are just wrong because they've got the mode 2 functions wrong also).

I've been wondering if my Futaba FF7 transmitter would work (if I bought an appropriate crystal) or are these FM electronics only compatible with the same make?

[Mart61]

Without knowing the model, or seeing the manual, I can't say if the radio will be configurable or is another Tx would work.

Is it too late to take it back and get a refund?

If you can do this, go buy a Blade mCX - it's about the same price (maybe £20 more) and, from what I can see, far superior to the model you bought.