Variable pitch propeller - Pilatus PC-21

[Kristian Aareskjold]

Hi,

I would very much appreciate a piece of advice on how to measure current draw ( method and equipment) from a Hacker motor (A 50- 14S) to set optimal pitch on a variable pitch propeller ?

I have a Seb Art P-21 Pilatus recently fitted with a 13" - 5-blade Varioprop from Ramoser which I need to select a pitch setting on. The power set up includes a Master Basic 70 SB ESC and a 5S, 4000mah LiPo.

Anybody with a similar model/variable pitch propellar that could advice me on tha matter would be highly appreciated.

Regards

Kristian Aareskjold

Tananger/Norway

[Olly P]

Kristian,

I don't have any Variable pich props, but do use a variety of props on a new set up to get the best one for the job.

I would recommend an inline watt-meter with current display as the measuring tool, these are available from giantshark in the UK, and there must be a Norwegian supplier, or you could get one from HK.

I would then set the prop at a fine pitch, measure current/wattage, adjust and repeat. obviously removing the battery while adjusting.

What the 'best' pitch will be will depend on what you want the aircraft to do....

[TheFlyingCrust]

Hi Kristian and welcome. I'm fairly new to electric power, but have you tried using an in-line watt meter? Also available, but a bit expensive, are Hall effect clamp meters , which will measure current - although you wouldn't want to carry one of those in your plane! If you buy the clampmeter be sure it will do what you want.

Ian

[Andy48]

I hook a cheap electronic luggage balance tethered to the back of the plane and attach that to a secure mount on smooth ground. Then you can experiment with different propellers and in your case the pitch whilst watching the power input from a wattmeter. Its never going to tell you what the plane will do in the air at any speed but its a good starting guide.

Of course this only works with a plane with an undercarriage.

[Martin Harris - Moderator]

On-board telemetry or data logging has to be the answer. That way you can analyse the actual loads in flight. If you get someone to video the flight and compare the two you can relate the data to various flight phases, level flight, cruising, down lines etc.

 

Edited By Martin Harris on 05/04/2013 20:00:13

[ben goodfellow 1]

i have an axi evp unit for 4d , on a heli setting and with a watt meter hooked up i gradually increase the pitch curve till the watt meter reads the maximum rated amperage of the motor, i dont know about your unit but i found it didnt take much to affect the setting, heat ,cold a hard knock and the amps would go up and down , very fiddley and very annoying