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RV-10 Glide Ratio

C

Chippster1

Active Member
I was out today on a beautiful windless day doing some experimenting with glide ratio in my 10.

I was pleased and a bit surprised to find that it calculated out at about 12:1 at idle with the prop full back and 85KTS

Anyone else out there get such good numbers?

Ted Chipps

N498EC
 
Probably best to do your testing with the prop full aft (fine pitch). With an engine failure there is a good chance you would have no oil pressure thus fine pitch.
 
flyinga said:
Probably best to do your testing with the prop full aft (fine pitch). With an engine failure there is a good chance you would have no oil pressure thus fine pitch.
Click to expand...

Ummm prop full aft is coarse pitch (aka high blade pitch and low RPM). "Fine Pitch" is prop control full in which commands low pitch angle and high RPM.
 
That's really surprising

I used to own a DA-40 and still have a DA-20. The published glide ratio for the -40 is around 11 to 1 for a propeller stopped and less than 9 windmilling.

This is an all composite airplane with a high aspect ratio 40 foot wing.

I guess it's possible but I suspect the numbers you are attaining are a bit optimistic .
 
KatanaPilot said:
I used to own a DA-40 and still have a DA-20. The published glide ratio for the -40 is around 11 to 1 for a propeller stopped and less than 9 windmilling.

This is an all composite airplane with a high aspect ratio 40 foot wing.

I guess it's possible but I suspect the numbers you are attaining are a bit optimistic .
Click to expand...

Yeah, I would be extremely surprised at even 10:1. I conservatively use 6:1.
 
Jesse's rule of thumb is a good one. I saw 7.5/1 or 1.4 NM per 1,000 ft in flight test with engine at idle, prop full fwd.

Dave
 
You're right, I did the math wrong. I did acheive 1.4 NM per 1,000 feet, or 8.4 to 1.

==dave==
N102FM
 
Garmin Virb for flight testing

Here's a short video clip of how I used the Garmin Virb Elite to determine my best glide. This run was at 90 KIAS (more or less), and descending through 5,000', I started my Davtron timer. After one minute had elapsed, I noted my altitude loss - 780 ft. in this case. The little GPS distance counter over on the right of the screen started at 0.20 NM and was at 1.86 NM at the end of one minute for an elapsed distance of 1.66NM. Multiplying by 6080.27 gave me a forward distance in feet of 10,093'. Dividing that by the altitude loss of 780' gave me a glide ratio of almost 13:1. The "landing gear" nag from my AoA was going off the whole time because my gear were up when I was below 95 Kts. Later, I repeated the test far away from any mountains and came up with 12:1 glide ratio. That time I did the test in reciprocal directions to (hopefully) eliminate any error due to wind. (I never wanted to be a flight test engineer.)

https://www.dropbox.com/s/nj0td4ubl5ipjq1/05-24-16 Best Glide_90 Kts.mp4?dl=0
 
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