HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Sep 20, 2005, 09:12 PM
Will fly some day
willfly's Avatar
Brampton, ON
Joined Dec 2003
361 Posts
Skimmer 400 L/D ratio

Of those who have experience with this plane, what would you say the L/D ratio of this plane to be. My guess was from 20 - 30, but in hand tosses, I found it to be close to 12 at best glide. I find this low, since it seems to be a clean design.
There could be problem with my build, I have a feeling that leading edge is a bit thicker than it should be.

For reference, are there any known L/D figures for popular planes like Gentle Lady, Wind dancer etc.

My WW Sport 2 Hang glider is at 10 and Grob 103 sailplane I flew couple of times is 36.
willfly is offline Find More Posts by willfly
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 21, 2005, 06:04 PM
xtc
outrageously large member
xtc's Avatar
no-where near tx
Joined Feb 2004
937 Posts
Quote:
Originally Posted by willfly
Of those who have experience with this plane, what would you say the L/D ratio of this plane to be. My guess was from 20 - 30, but in hand tosses, I found it to be close to 12 at best glide. I find this low, since it seems to be a clean design.
There could be problem with my build, I have a feeling that leading edge is a bit thicker than it should be.

For reference, are there any known L/D figures for popular planes like Gentle Lady, Wind dancer etc.

My WW Sport 2 Hang glider is at 10 and Grob 103 sailplane I flew couple of times is 36.

all i can say is ,,i wish my wills wing ramair had a glide ratio like the skimmer
xtc is offline Find More Posts by xtc
Reply With Quote
Old Sep 21, 2005, 10:28 PM
Registered User
John Gallagher's Avatar
Lindenwold, NJ, USA
Joined Dec 2000
3,142 Posts
Quote:
Originally Posted by willfly
Of those who have experience with this plane, what would you say the L/D ratio of this plane to be. My guess was from 20 - 30, but in hand tosses, I found it to be close to 12 at best glide. I find this low, since it seems to be a clean design.
There could be problem with my build, I have a feeling that leading edge is a bit thicker than it should be.

For reference, are there any known L/D figures for popular planes like Gentle Lady, Wind dancer etc.

My WW Sport 2 Hang glider is at 10 and Grob 103 sailplane I flew couple of times is 36.
You can't measure L/D close to the ground (from a hand toss). Ground effect would exagerate the results.


What part of NJ are you from?
John Gallagher is offline Find More Posts by John Gallagher
Reply With Quote
Old Sep 22, 2005, 03:42 PM
Will fly some day
willfly's Avatar
Brampton, ON
Joined Dec 2003
361 Posts
Plainsboro, close to Princeton.
willfly is offline Find More Posts by willfly
Reply With Quote
Old Sep 22, 2005, 07:34 PM
Registered User
FWFlyer's Avatar
United States, IN, Fort Wayne
Joined Nov 2003
117 Posts
Quote:
Originally Posted by John Gallagher
You can't measure L/D close to the ground (from a hand toss). Ground effect would exagerate the results.
OK. So how can we get L/D figures for a plane?

Also, how much would you say ground effect adds? Is there any way to measure ground effect?
FWFlyer is offline Find More Posts by FWFlyer
Reply With Quote
Old Sep 23, 2005, 03:58 AM
HyperFlight Support
Neil Stainton's Avatar
United Kingdom, England, Stratford-upon-Avon
Joined Feb 2001
3,865 Posts
Ground effect can reduce induce drag by 50% or more. Also when you hand launch a plane you are giving it an uncertain amount of energy, you aren't just inserting it into the moving air wth all the forces in equilibrium. You can't get the L/D of a plane accurately without using a wind tunnel.

The EagleTree telemetry/recording system allows velocity and altitude to be measured, but
a) I am not sure if it is accurate enough.
b) From my altitude only recording tests using a RAM2 I know that even on totally still evenings the air is moving gently, and every glide results in differing sink rates, varying from eg 50 fpm to 80 fpm.

Neil.
Neil Stainton is online now Find More Posts by Neil Stainton
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Best L/D Ratio gsr916 Sailplane Talk 30 Apr 11, 2006 12:36 PM
Anyone own a Skimmer 400? Do you like it? Jaymz007 Electric Plane Talk 4 Jun 09, 2001 04:31 PM
Folder for Skimmer 400 GaryK Electric Sailplanes 1 May 16, 2001 10:17 AM
Skimmer 400 questions luv2fly Electric Sailplanes 1 May 10, 2001 11:05 PM
Bought a Skimmer 400 kit today luv2fly Electric Sailplanes 6 Apr 21, 2001 12:00 AM