Feathering Propellors

[sp250]

I have in mind a four stroke petrol engine with electric start for a large scale powered glider project.
Are there any feathering props commercially available that are suitable and safe for IC engines on the market?
The cowl shape precludes the obvious electric power option with a folding prop.
Hoping for a feathering prop solution to reduce drag on the glide.
Thanks John M

[Elliot Howells]

John, I looked long and hard at this problem some time ago. The only feathering props I could find are vario props, and tyhey feather manually, when you take them apart...

Thought about adapting a large scale heli mech, but honestly, the thought of those blades letting go made me conclude a folding prop and a leccy motor was the ideal solution.

Ell.

[Barry_Cole]

John,
The fact that you have stopped the prop, rather than having to motor at idle, will make a big difference.



BC

[sp250]

Elliot, yes Vario Prop were the only supplier I could find too. Have emailed them with questions. Can't use electric & folding prop as the cowling is not suitable, it might trap one blade and prevent restarting. Vivat has an inverted aircooled engine so cowling is like a Tiger Moth.

Barry stopping the engine was the bit I thought might make the difference, then an interlock switch so it can't be started till the prop pitch is returned to flying angle from feathered.

I see from Noel Rumers SFS31 Milan electric powered build pictures on here 2021 there are some showing the prop blades feathered. Which is what prompted me to ask this question and the use of a four stroke was for a more realistic sound.

John M

[sp250]

My mistake the pic in Noels build is of the full size with feathered prop.
John M