Mayfly - by Peter Valentine

Here’s one for Pete
Retro helicopters
Pchristy
Posts: 373
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Mayfly - by Peter Valentine

Post by Pchristy »

My 200kV motor finally arrived yesterday, having spent nearly a month traveling from Hong Kong! It seemed to spend nearly a week in Switzerland or Germany (different tracking apps gave different answers!) and a few more days at Heathrow, but it finally arrived, and I installed it last night.

A test hover in the garden gave me the full 4 minutes hovering, with the 60A ESC not even getting warm! (It got too hot to touch with the previous motors!) Emboldened by this, I tried the 40A ESC again. This did get hot - not too hot to touch, but definitely hot! I've therefore gone back to the 60A one for the sake of safety!

Despite the dramatic reduction in kV from my initial successful flights, it still flies at exactly the same throttle settings, indicating to me the importance of getting the kV rating correct. On an aeroplane, its easy to adjust the prop to suit the motor. On a helicopter, you are stuck with the rotor size, and may not be able to adjust the gearing easily. It is therefore necessary to "guesstimate" the required kV.

This isn't too difficult on an IC powered heli, as you will know the peak RPM of the engine for which it was designed (typically around 12,000rpm for a 2-stroke glowplug), and the voltage of the pack you intend to use.

However, this was an experimental heli designed around a geared, brushed motor, so I had no "yardstick" to use as a starting point.

Got there in the end, though!

Once the lockdown ends and given a decent day's weather, I'll get some video of it in action!

Cheers,

--
Pete
Jim
Posts: 28
Joined: 09 Oct 2021, 21:56
Location: Cambridgeshire, England

Re: Mayfly - by Peter Valentine

Post by Jim »

Hi Pete

Did you fly your Mayfly again? Interesting to know if you got beyond the test hover with this machine after swapping the motor again.
Pchristy
Posts: 373
Joined: 16 Feb 2018, 13:57
Location: South Devon, UK

Re: Mayfly - by Peter Valentine

Post by Pchristy »

Yes, its flown a few times - I even flew it at Ponty a year ago! I don't fly it much, as its more of a novelty than a practical helicopter. Its too light to fly in any appreciable wind, and any spares needed have to be made from scratch!

It really belongs in a museum. Maybe when the BMFA finally get around to opening one, I'll donate it!

:D

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Pete
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