RE: 1/2A THRUST-O-METER
I picked up a stock TD from an RCU auction, and thought it would be interesting to see how much it could "bench press" with different props. I used 30% fuel, and a NELSON head. This engine didn't need a breakin by me, the original user did a nice job. For the test it was run on bladder. It was too dark to get tach readings, but I would say it sounded like a 21-22K engine with the 5-3 prop.
PROP THRUST OZS. COMMENTS
COX 5-3 14.4 wide needle
COX 6-3 16.6 that equals the weight of the gondola & nineteen 1/2" nuts.
COX 6-4 16.6 might as well run a 6-3, this one runs hot
FG 4.5-2.5 10.6 Great prop [fiberglass] for CL combat
APC 5.7-3 17.4 WOW!
APC 5.5-2 16.2 had to open the needle for this one, easy to needle, cool run
GRISH 5-3 13.8 good prop for weak engines
GRISH 5.5-4 15.0 never had any use for this one, needs to be cut down
GRISH 4.5-4 14.4 OOPS! see above comment
WOOD 7-2 14.4 had to close needle way down, ran ok
I think it would be interesting now to slap on a diesel head and go through this again. I don't have an APC 7-3 or I would do this test ASAP.