VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 06-02-2019, 06:16 PM
jeff beckley jeff beckley is offline
 
Join Date: Jan 2006
Posts: 192
Default Glide ratio

What is the glide ratio for a 7a?
__________________
Jeff Beckley
Des Moines Iowa
Van's RV-7A
Reply With Quote
  #2  
Old 06-02-2019, 08:17 PM
tgmillso tgmillso is offline
 
Join Date: Nov 2012
Location: Launceston, Tasmania, Australia
Posts: 738
Default

Depends on your propeller choice (CS vs Fixed), altitude, airframe cleanliness, speed you descend at (maximum range or minimum descent rate) etc.
A ballpark number is 1nm for every 1,000ft of elevation loss.
Best bet is to go out and take a few measurements and put the results in your POH.
Tom
RV-7

Last edited by tgmillso : 06-03-2019 at 06:28 AM. Reason: Removed "weight" from the parameter list. That said, weight change will affect the glide ratio if the same IAS is maintained.
Reply With Quote
  #3  
Old 06-02-2019, 08:27 PM
Kyle Boatright Kyle Boatright is offline
 
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 3,855
Default

The CAFE foundation did a thorough test of a fixed pitch RV-6A that was published in Sport aviation in 1993. I don't remember which month.

Anyway, I seem to remember the glide ratio was approximately 10:1 at 100 mph.

A fixed pitch RV-7 should be similar.
__________________
Kyle Boatright
Atlanta, GA
2001 RV-6 N46KB
2019(?) RV-10
Reply With Quote
  #4  
Old 06-02-2019, 09:02 PM
BobTurner BobTurner is online now
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,986
Default

Quote:
Originally Posted by tgmillso View Post
Depends on your propeller choice (CS vs Fixed), weight,
RV-7
While the no-wind speed for maximum glide distance does depend on weight, the actual no-wind glide range, if flown at best speed, is independent of weight. You just get there sooner, if you're heavy.
Reply With Quote
  #5  
Old 06-02-2019, 11:11 PM
Ali Ali is offline
 
Join Date: Apr 2019
Location: Chandler, AZ
Posts: 10
Default

On a related question, what is the optimal speed for best glide ratio? That should be fairly similar for most RV 7s with the same engine.
Reply With Quote
  #6  
Old 06-03-2019, 01:50 AM
BobTurner BobTurner is online now
 
Join Date: Dec 2011
Location: Livermore, CA
Posts: 5,986
Default

Quote:
Originally Posted by Ali View Post
On a related question, what is the optimal speed for best glide ratio? That should be fairly similar for most RV 7s with the same engine.
That depends on the weight, and, in the real world (if you’re concerned with distance covered over the ground), the wind velocity.
Reply With Quote
  #7  
Old 06-03-2019, 02:07 AM
flyvans.com flyvans.com is offline
 
Join Date: Feb 2005
Location: Zurich, Switzerland
Posts: 448
Default

one thing to consider in my opinion - should you get into the situation that this data may become necessary, such as in an engine failure - it may be impossible to put the prop to coarse pitch as this requires oil pressure... fine pitch
with a windmilling engine results in really poor glide performance. more like 1:8 around 85-92kts...
on the other hand, should the engine seize, the prop factor is yet a completely different animal with improved glide performance expected.
__________________
++++++++++++++++++++++++++++++++
Bernie Daenzer, Alex Lichtensteiger
www.flyvans.com
RV-7A
S/N 72072, Flying!
HB-YMT (Switzerland)
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 06:30 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.