Helicopter run-up?
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RatherBeFlyingInCanada
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Helicopter run-up?
How is a Helicopter "run-up"? Is it done in the same manner as a fixed wing bird or is it done differently?
"Keep thy airspeed up, lest the earth come from below and smite thee."
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rotorfloat
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With regard to piston-engined helicopters, the run-up is similar. Mag checks etc. Not sure of the exact rpm, the pistons I've flown have tachs in %. Same tolerances though....so many % drop in 2-3 seconds.
Aside from that, there's no call for mixture checks or live-mag checks or anything...on robbies anyways.
One more piston-procedure is to ascertain that the rotors will disengage from the drivetrain in the event of an engine failure. This is usually done by running it up to mid-rpm or so and closing the throttle. You should see the engine rpm needle split from the rotor rpm needle. The engine rpm should drop down to idle and the rotor rpm should slowly wind down. If the rotor tach drops with the engine tach, then your free-wheeling unit is not disengaging and you do not go flying.
On turbines, depending on the model, there's a warm up period before going to flight rpm and then control and hydraulic checks are done. Usually the first flight of the day includes the free-wheeling unit/decel check.
Some models have an mid-rpm range where the tail-rotor driveshaft reaches a certain harmonic and will try to flail. It's usually indicated on the tachs as a coloured arc through the sensitive rpm range. The manual usually calls for accelerating through that rpm range and avoiding it during run ups/cool downs.
Other than that, it's the same as anything else...temps, pressures, warning lights, etc.
As with anything, when you get familar and comfortable, all your checks can be complete in very short time. I can usually have them off the ground about 2 minutes after startup, if it's warm out. Winter startups require more time to warm up the engine and transmission oils.
Feel free to ask any other questions
Aside from that, there's no call for mixture checks or live-mag checks or anything...on robbies anyways.
One more piston-procedure is to ascertain that the rotors will disengage from the drivetrain in the event of an engine failure. This is usually done by running it up to mid-rpm or so and closing the throttle. You should see the engine rpm needle split from the rotor rpm needle. The engine rpm should drop down to idle and the rotor rpm should slowly wind down. If the rotor tach drops with the engine tach, then your free-wheeling unit is not disengaging and you do not go flying.
On turbines, depending on the model, there's a warm up period before going to flight rpm and then control and hydraulic checks are done. Usually the first flight of the day includes the free-wheeling unit/decel check.
Some models have an mid-rpm range where the tail-rotor driveshaft reaches a certain harmonic and will try to flail. It's usually indicated on the tachs as a coloured arc through the sensitive rpm range. The manual usually calls for accelerating through that rpm range and avoiding it during run ups/cool downs.
Other than that, it's the same as anything else...temps, pressures, warning lights, etc.
As with anything, when you get familar and comfortable, all your checks can be complete in very short time. I can usually have them off the ground about 2 minutes after startup, if it's warm out. Winter startups require more time to warm up the engine and transmission oils.
Feel free to ask any other questions
yup, that pretty much sums it up right there.
You may have to prime the engine/carbeurator first before starting the engine depending on how cold it is out. But other than that, mag checks, sprag clutch check, and making sure everything is dropping when its supposed to etc is how the robbies start up anyways.
Iv had a few flights in planes and if i remember correctly it wasnt as different. Probably the only real similiarity b/w them!
You may have to prime the engine/carbeurator first before starting the engine depending on how cold it is out. But other than that, mag checks, sprag clutch check, and making sure everything is dropping when its supposed to etc is how the robbies start up anyways.
Iv had a few flights in planes and if i remember correctly it wasnt as different. Probably the only real similiarity b/w them!
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RatherBeFlyingInCanada
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- Joined: Thu Oct 12, 2006 2:10 pm
