Thursday, 3 March 2011

RC helicopters


I've been playing with a few of the Remote Control helicopters lately, and compared to the little one I bought from Jaycar some couple of years ago things have really improved.

This little foam bodied fella was the first RC Heli I bought ...

It was unstable and never flew well ... hard to master.

Then just 2 years later they've created the coaxial type (note the two rotors)


That one is the Doublehorse 9098 ... which is very easy to fly and a bunch of fun indoors (like at the office). The coaxial actually don't need the tail rotor for turning (that's done by varying the speeds between the top and bottom rotor) they instead use the tail rotor to tilt the chopper forward or backwards ... and thus thrusting forward. You can see the difference clearly here.


Both have "balance bars" to alter the pitch on the blades to keep stability (which spinning as a gyro effectively stablise the craft).


While the 9098 was a gas inside it struggles with even the slightest "breeze" that the air conditioning can bring ... meaning not much. Further the IR control means that outside in the sunlight it gets out of range real fast.

Enter the Doublehorse 9053 coaxial helicopter.

This is nearly 70cm long and is huge in comparison to the 9098. It comes with an actual Radio control and works outside. However as standard has a few problems. For instance the upper and lower blades often collide in windy conditions and the tail rotor blade has not enough power to cope with windy conditions.

the result is crashes ...

So I've made a few modifications to mine (that are found on youtube) to make it more stable and controlable:
  • invert the mount for the bottom blade (and then flip the blades back)
  • enhance the rear tail rotor fan with greater size blades

As it happens the balance bar from a 9077 chopper fits straight on and also looks perfect too.

To address the lacking in thrust from the tail fan, I cut down the spare bottom main blades from my above mentioned 9098 and used a good plastic glue (Tarzans grip in this case) to affix them to the ends of the existing fan ... you can see that in the video below:

The inversion process for the bottom blade is reasonably easy and can be found on youtube too.

a quick test flight this morning at home shows that it works a treat


after a quick test outside at lunch in light breeze I'm still getting blade strike (brining the chopper down fast). Also for some reason the RC is intermittently getting through at some ranges meaning that when I control forward it doesn't and when I try to stop a turn it doesn't.

You can see I was having some RC responce problems as well as hear towards the end some 'clacks' of the blades striking.

hmmm ... more work needed


Jao said...

Pretty cool! Could you hang a camera from it?

obakesan said...


definately ... but only a small one.

It could make a cheap camera platform, as it will definitely lift a small payload.

BUT vibration is an issue, you'd need to be sure it was tuned up well to not vibrate ... no bent anything