Well guys i finall was able to have my GP shoestring clocked. She was clocked at 109mph flying into a 15-20mph head wind with a 12x8 apc prop. I have a .91fx with a bisson pitts muffler in it i also have modded the wings and sunk the aileron servos into it. After i got home from that day i have since sealed the gaps and changed the prop to a 13x7 apc and she seems faster with that prop. I have yet to get out to the field and see if sealing the gaps will have helped with its top speed. So i figure with no head wind im lookin at around 120-130mph when all said and done.

The craziest thing is i fly basic IMAC with this plane!

See ya around

THats about right. Mine has a G90 with a 13/8 and its around the same.

What fuel you usin?[8D]

I use 15% Omega. I know others use lower but I use that on every engine I have with no problems for a few years now

15% omega

my 91fx only runs good using wild cat ys20/20 ,and using a needle valve off of a 61 fx. the needle from the 91 has a blunt end, where as the needle of off the 61 is tapered all the way down to a point for better refinement. with that combination using a 13x8 apc i am getting just a little over 11,000 rpms. Dont know what speed that is, but it does haul ass in my Shoestring. Had that same set up in my midget mustang until it bit the dust.

ken

well guys i changed the prop on it and got it clocked again this time it was 123.5mph. I then had a little bit of bad luck and clipped a wing tip on the ground while it was being clocked at 101.3mph the surprising thing is it didnt destroy the airplane all it did was clip both wing tips. i will post pics of it later. THIS IS ONE TOUGH AIRPLANE!!!

Flyguy, what prop did you change to? I'm building my String and plan on using the G90, even though everyone local says to go with the 91fx. Is there REALLY that big of a difference between the FX and the G90 (other than $85)? I've heard the FX will idle down better which would be nice on a high pitch prop, but is there that big of a difference in top speed?

the .91 is lighter then the G90 thats the only major difference that i know of. I was using a 13x7 apc prop when it was clocked at 123.5 when it was clocked at 109 it was a 12x8apc.

here is a picture after i hit the ground at a clocked speed of 101.3mph this thing is strong!!!

My Shoestring has an os61 but I also have an os91fx that runs great but has been sitting on the shelf looking for a new home. What modifications would you recommend to the Shoestring to handle the added stress. I have already fiberglassed the center section of the wing. What about the firewall and the tail section?


Thanks
Mike

I run a G90 in mine. I always ad some strength around the inside and outside of the firewall to make it more secure to the fuselage. I have not really made an other mods in 4 years and its still fine

all i did was fiberglass the center section. For speed mods i hid the aileron servos in the wing and sealed all the hinge gaps. The only thing with the 91 is some cooling issues but i have since worked them out. block off the left side of the cowel and open up the right side cheek for increased airflow. also make sure you have adequet (sp) exit airflow

Thanks for the info. I'll make the mods tonight


mike

sweet i think you will like it