Collective pitch changes thru translational lift

StanFoster

Active Member
Joined
Nov 16, 2003
Messages
16,980
Location
Paxton, Il
Aircraft
Helicycle N360SF
Total Flight Time
1250
Using my collective pitch degree tool....I checked my collective pitch from 0 thru 80 mph......past my MPRS. I already have data to 15 degrees from several other runs. This was intended to show how you need less collective in hover....then need a little more collective as you leave the benefit that hovering in ground effect gives you....then how translational lift kicks in and gives you decreasing pitch requirements until you reach MPRS, then starts increasing due to other drag increasing more than the continually shrinking induced drag because of translational lift.

I find this tool giving me some valuable information. Here are my results from hover to 80 mph. These speeds were taken from my very accurate GPS ind absolutely dead calm conditions this morning.


0 hover...........................10.75 degrees

10 mph............................11.25 degrees

20 mph........................... 10.5 degrees

30 mph.............................9.25 degrees

40 mph.............................9.0 degrees

50 mph..............................8.25 degrees

60 mph .............................9.0 degrees

70 mph..............................9.75 degrees

80 mph..............................10.25 degrees

The picture shows 10 degrees of collective on my linear chart alongside my cabin door.


Stan
 

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