I just got a Tiger G-51 and installed a Great Planes 2 1/4" spinner on the crank shaft in the following sequence:

Spinner Back plate
11 X 5 fiberglass prop G/F 3 Seres Master Airscrew
Prop Washer
Nut with 1 1/2 turns till tight

My concern is I am only utilizing 1 to 2 threads to hold the prop on half the nut is not used as the shaft is to short

Is this normal or do I need or miss something????

DON'T Start the engine with only 1 or 2 threads on the nut it simply is not enough. I avoid spinners and like to use the aluminum hubs that replace the prop nut. this on is for 049 but they come in all sizes. A picture would help a lot if your able.

That's a big problem with MAS props. Use an APC, Evolution or Zinger prop. If you're adamant about using an MAS prop, then you might have to either get an extention or run it without the spinner.

Or use one of these.

http://www3.towerhobbies.com/cgi-bin...&I=LXE158&P=ML

i agree if you are gonna use a spinner get yourself an extension and the spinner adapter setup that cgretired has posted is a good setup they are a little small but will work the spinner is the prop nut. apc prop centers are much thicker than mas props.i like the metal spinners that have the bolt adapters you use a setscrew in the front center to tighten down the spinner.

Every MAS prop I've ever had has been WAY thicker in the hub than an APC.

Or use one of these (1/4x28 for the G51). The prop gets drilled/reamed out to suit the OD of the T nut.
http://www3.towerhobbies.com/cgi-bin...&I=LXB952&P=ML