Birdie 10 electric conversion
 

This model should be about 35 - 40 oz
300 sq in. I have been planning on using a
Eflite power 10 on 3 cells. I only have 4" of
Ground clearance so prop selection is the controlling
factor.
Any suggestions?

Thanks

If you must use a 7" prop, you'll have to run that motor on 4s or 5s to get enough power. With 7x5 on 4s you'll have 225W/25oz thrust... might be enough. On 5s you'll have 400W/38oz thrust (too much for the motor?)

Has anyone looked at using a 4 blade prop for limited ground clearance models?

Vario make 4-blade hubs and provide blades down to 5.6".......http://www.eam.net/Varioprop/Vario%20Prop.htm