View Full Version : head speed checking methods question
is it possible to check the head speed by using the usual optical tacho on the paddles with the main blades removed?
or
also with the main blades removed could you use the tail rotor speed to work out the head speed?
i want to see what sort of speed i am getting at various throttle points with out taking off. I assume that a unloaded head speed measurement like this will not be 100% accurate but I assume it will be close.
many thank for any advice
Alistair
DebianDog
12-05-2006, 05:05 AM
Yes
Yes once you figure out your gear ratio.
Unfortunately you have to have pitch and put a load on the motor to get an accurate reading. Just because at 75% throttle you are getting 2000 RPMs with NO blades and NO resistance you will be NOWHERE near your flying headspeed.
If you do not want to take off - Set it up to only apply negative pitch but... I would highly recommend you do it the tried and true way of a solid hover.
BarracudaHockey
12-05-2006, 10:37 AM
Running up an unloaded engine is a very bad idea btw.
bgjames111
12-05-2006, 10:42 AM
I had a customer come in yesterday that tried to "bench run" his engine with only the clutch installed. Net result: broken clutch and a broken connecting rod. He's luckya piece of clutch didn't end up in his face. He gave me a blank stare when I told him that you should never run the engine without a load on it.... :arggg:
BarracudaHockey
12-05-2006, 10:59 AM
You should have handed him a 3x5 card printed up with
"Here's your sign"
jongurley
12-11-2006, 06:13 PM
Actually "Here's Your Sign Stupid"
BarracudaHockey
12-12-2006, 03:12 PM
Actually the correct use, according to Jeff Foxworthy is to hang a sign saying "I'm Stupid" around their neck, so if you see the sign, you know not to expect much out of them.
Rickenbacker
12-29-2006, 05:35 PM
I would really recommend measuring the headspeed in a stable hover. Otherwise what are you measuring? Nothing useful.