great stuff - thanks for the reply. Explanation makes sense, given I need it in front of the firewall



i will need the back mounting kit which states it comes with

PARTS INCLUDED
1) Back-Mount Prop Adapter - M6 x 24mm Prop Shaft
3) M2.5 screws for adapter
1) 5mm Retaining Collar, Steel
1) Prop Shaft Washer
1) Prop Shaft Nut
4) M3 Allen Head Bolt 12mm length
4) M3 Allen Head Bolt 20mm length
20) 1.95mm Hard-Ply Firewall Spacers (9.7mm OD, M3 ID)
20) 2.85mm Hard-Ply Firewall Spacers (9.7mm OD, M3 ID

You are right this is for the Sig 4 star 20 EP.

http://www.rcgroups.com/forums/showthread.php?t=1315989

I'm glad you mentioned that Zs31014-14 motor as I'm in two minds whether that is a better one to go for. I'd like 400w of power and it seems like I will have to drive the 3009-20 hard to achieve that, especially as it is rated for 18-26A typical usage.

AUW of the 4 star 20 EP is around 38oz. What do you reckon? Your motor is obviously heavier and border line weight for the sig.

The Motrolfly is not available in the UK so not an option.

thanks David for the info and Scorpion suggestion. Guess I need to balance this power against flight times with a 2200 lipo.

Remembering the 3014 is 1 oz heavier.
If you can keep the weight down to 38 or preferably 36 oz. ESC, battery, wire length & lightweight covering, the 3009 is good. start off underpropped. Say 9x6 & check on watt meter + temps after flying. Move up prop size till you find the best balance. Often I haven't gone for the highest power because the trade off in torquing left on take off or duration weren't worth it. anything over 100 watts/lb INPUT in a high efficiency motor is good.

any idea how much weight the back mounting kit ads? Also I notice they sell

http://robotbirds.com/catalog/produc...oducts_id=5294

so does this mean the stock motors don't come with the hardened shafts?

Originally Posted by cirrus_uk

any idea how much weight the back mounting kit ads? Also I notice they sell

http://robotbirds.com/catalog/produc...oducts_id=5294

so does this mean the stock motors don't come with the hardened shafts?

Initial production run. Recent are fully hardened.