Thorp Air Command - T18.net

HI, I AM NEW TO THE FORUM. I BUILT MY T18 AND IT HAS 400HRS ON THE CLOCK. A GREAT PLANE AND WOULD NOT TRADE IT FOR AN RV. IN CRUISE ABOUT 145KTS AND FASTER IT SOMETIMES HUNTS FORE AND AFT ABOUT ONCE PER SECOND. YOU CAN FEEL IT IN YOUR SEAT BUT NO RPM OR AIRSPEED CHANGE. THE ENGINE HAS CARBY RAM AIR AND FIXED PITCH SENSENICH PROP. I HAVE SELECTED CARBY HEAT BUT THE RPM DROP MASKS THE HUNTING. THE FWD ACCELERATION WOULD HAVE TO BE A FEW KNOTS. THERE IS NO NOTICABLE VIBRATION CHANGE. MAYBE SOMEONE IN THE FORUM HAS COME ACROSS THIS PROBLEM. BOB. AUSTRALIA. VH-WKV.

I have felt this after power changes and occasionally in turbulence. It is fuel sloshing forward and aft in main fuel tank. If tank is full, it won't do it. Fill your tank full and see if you can duplicate the surging feeling.

Bernie Fried
N18xs

Hi Bernie, thankyou for the help, I will try 3/4 full tank to replicate the problem. I mostly only fly with about 50lts which is why the hunting doesn't happen much. Bob Veale.

Hi Bernie,

I never would have thought of that... you are so perceptive!
Gonna' be at OSH?

Take care!

_________________
John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

Hi John,

Melva and I plan on going to Oshkosh. Don't know if I'll have the Thorp there or not. Putting a different engine in and not sure if I'll have it ready in time.

Hope to see you up there!

Bernie
N18XS