Brian Jackson
Platinum Member
- Joined
- Jul 17, 2004
- Messages
- 3,524
- Location
- Hamburg, New Jersey USA
- Aircraft
- GyroBee Variant - Under Construction
An academic question to the more informed...
When performing a double hang test to pinpoint VCG, I understand the blades must be on because they are a significant portion of the AUW. However, I imagine there is a measurable change in COM of the rotor when its sagging vs. coned in flight. Rough mental guess; maybe 1/3 of total tip vertical deflection (I can do the math later). But whatever the ratio, it will change by some amount. We'll call it 2" for now just for demonstration. We'll call the rotor 50 lbs. and AUW 500 lbs to keep the math easy. So in this example adding an inch to rotor height moves the VCG of the ship+pilot 1/10". Thusly, our 2" change in rotor COM would affect a 2/10" change in the ships VCG.
Granted it's not huge, but I'm curious if this coning angle difference is generally taken into account. I don't recall reading about this in the archives. Thanks.
When performing a double hang test to pinpoint VCG, I understand the blades must be on because they are a significant portion of the AUW. However, I imagine there is a measurable change in COM of the rotor when its sagging vs. coned in flight. Rough mental guess; maybe 1/3 of total tip vertical deflection (I can do the math later). But whatever the ratio, it will change by some amount. We'll call it 2" for now just for demonstration. We'll call the rotor 50 lbs. and AUW 500 lbs to keep the math easy. So in this example adding an inch to rotor height moves the VCG of the ship+pilot 1/10". Thusly, our 2" change in rotor COM would affect a 2/10" change in the ships VCG.
Granted it's not huge, but I'm curious if this coning angle difference is generally taken into account. I don't recall reading about this in the archives. Thanks.