franc
New Member
Posts: 8
Name / Surname: Francois Paul
Main flying location: Region, Country: Netherlands
Two or three axes controls: Three axes
Administered_by: Christian
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Post by franc on Apr 17, 2022 11:04:59 GMT 1
I know the polar curve for each pilot&swift'light combination will be slightly different, and of course will look different for each flap setting, and will look different at different barometric altitudes and atmospheric conditions. But, I'm setting up a my flight computers for my new Swift Light, and I'd like to start with some reasonable and conservative polar setting - which I can then adapt over time to be closer to reality.
Is there a "standard" polar curve somewhere? Or does anyone have a representative set of curves / measurements that can be used?
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Post by Christian Hugon on Apr 17, 2022 11:41:19 GMT 1
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Post by Michel Paté on Apr 18, 2022 8:06:28 GMT 1
Hi guys, The polar of the swift "free flight" is there : drive.google.com/file/d/1BUanrP0IPp124RyT7nhfZb9t9NI058om/view?usp=sharingI assume that with a motor the L/D is roughly the same at a little higher speed. I have tested the stall speed with my SwiftLight-E and it is closed to 35 km/h. The true polar is very difficult to mesure. The best is to fly early in the morning , with no wind and no thermals, at différent flaps angles, with an oldie or compéo+... |
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Post by Christian Hugon on Apr 18, 2022 9:11:28 GMT 1
Hi Michel and François,
It is exactly what I did. I made my calculations very late in the evening when there was pratically no wind. I began at 1000 m altitude and I flew each speed each 10 km/hr. I flew once with the wind and once against the wind. For each speed, I adapted the flaps. It is the reason why I had this special polar. My best L/D is 23 and the stall speed is around 45 km/hr.
I think that the polar of the electric is nearly the same but with a higher L/D. I'm very surprised with your 35 km/hr stall speed for the E-Swift. I thought it was not far from my Swift Light PAS. For the Swift Light pure glider, it is around the 35km/hr.
The excel sheet I use for the calculation is very good to determine the numbers we need for the Oudie from Naviter.
Regards
Christian
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franc
New Member
Posts: 8
Name / Surname: Francois Paul
Main flying location: Region, Country: Netherlands
Two or three axes controls: Three axes
Administered_by: Christian
|
Post by franc on Apr 19, 2022 12:24:17 GMT 1
Thanks! I think these will give me a good initial polar to work with - and I'll be sure to measure and adapt my own
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