On Saturday 13th 2006f May 2006, Gary M. Edson wrote:

Hi Peter-- Brian Winch led me to your web site. Congratulations on a great-looking little engine! It's neat to see you follow in your Dad's footsteps but doing things your own way. I have a GB 5cc. Now I shall have to save (a lot of)$$$ to afford your little gem.
Question: How well does it run with larger props, 7x3, 8x3? For my diesel park fliers I like the lowest pitch I can find and length suited to an engine's lowest-range power capability.
Regards. -Gary Edson

Hello Gary,

I use a 7x3 propeller and 1/3,1/3,1/3 fuel blend for the initial hand-start test run.
Although they better suit the power range, my 6x3 and 6x4 propellers have thin blades and a low moment of inertia. Used with caution, the higher mass of a modified commercial 7x3 helps with the first start, but I do remain always aware of the tiny engine componentry. The 7x3 runs close to 8,000 rpm.

Using a low-mass, low-pitch, 7" propeller will be fine on a slow-flying model.
An 8x3 is way too large.

Peter