RC Helicopter coaxial rotors different speeds

[Callist]

Hi,

I am new to RC Helicopters and I was given a Feralbeast AH-64 APACHE helicopter. Needless to say I managed to crash it a few times and shred the plastic gears...

This leads me to two questions:

1. Where could I pick up spare parts for this helicopter? I reside in the UK.

2. I have stripped the plane down to the two motors and board and I can see that one motor does not even start to rotate until the stick on the contorl is at about 30%. This results in one blade spinning on its own until at the 30% mark is this normal?

Thank you and I hope to get valuable knowledge and eventually contribute from this forum!.

P.S - If this is the wrong section to post this to could someone please move it? Thank you.

[brin]

welcome to the forum mate .try here. AH64 Apache Spare Parts - RC helicopters, remote control helicopter

[Callist]

Brilliant. Thank you. Would you happen to know if the two motors running at different times is normal? i.e. one motor running at only 30% stick and higher.

[brin]

do they spin the same when you go past 30%

[Garth84x]

I found that on my co-axial that there was a trimming wheel on the transmitter that changed the rotor speed when moved left to right.

Does the heli stay tail in on take off or does it move around by its own accord?

[Callist]

Hi,

There is a trim switch and I was playing with it - I will check this tonight. I will also check if the speed is the same when above 30%.

P.S - The link you kindly provided me has the gears out of stock, would you know of any others? Thank you.

[owend]

I have a Blade mCX2 co-ax; the top rotor starts up straight away, the bottom one follows. This is because the bottom one rotates at a different speed to the top one; normally on a co-ax machine the two rotors' reactions (their torques) cancel each other out because they rotate in opposite directions at the same speed and the heli is stable - the default is both at the same speed which is why a co-ax can be trimmed to hover hands-off the transmitter.

It's why full size co-ax helis like the Russian Kamov series were used for antisubmarine, rescue, firefighting etc, where stability was a major requirement (they're also more compact as they don't need a tail boom, good news on a small ship!).

To turn the heli, the bottom rotor is slowed down or speeded up so the two rotors' torques don't cancel each other out, and the machine rotates. If I spool up slowly I can get the top one going without the bottom one (for academic interest, totally useless for flight!). So, depending on your heli, yes the motors could well start at different times/speeds. The test is if it's stable when it is developing enough power to lift off.