Newbie question.

hismiths

Newbie
Joined
Nov 28, 2019
Messages
7
Location
Kailua-Kona, Hawaii
Looking at the pics of all the various configurations, I have a question.

Why are so many of the aircraft designed with the seat or cockpit so high off the deck? I understand the prop clearance setting the engine up there, but why can't the seat be dropped closer to the ground? It seems to me that it would lower the vertical CG (is that a bad thing?), as well as allowing more free air to the engine.

Thanks
 

Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
2,906
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
The aim is to have the center of thrust pass through the vertical center of gravity so as to eliminate pitching moments. Low riders of the past tended to suffer from a dangerously high thrust line. Look up "Power Push-Over", or "PPO" in the search bar. The pilot represents a significant percentage of the aircraft's total weight, so raising the seat/pilot reduces or eliminates the thrust line offset. There are other design factors as well, but that's the main one. However I understand there are some stable lowriders if properly equipped with a sufficiently sized/located horizontal stabilizer.
 
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