REFLECTOR: Reflector Digest, Vol 87, Issue 104

John Abraham john at velocityaircraft.com
Tue Jun 19 18:46:24 CDT 2012


No,  that means from 2800 to 1000 over about 2.5 miles. I used a speed brake and gear to get down to the runway. No prop pulled back. 

On Jun 19, 2012, at 7:16 PM, Tom Falls <tomfalls6 at gmail.com> wrote:

> Getting worse John . . . . 1/2 mile is 2640ft . . . . Divided by 1000 is 2.6:1 . . . . !
> 
> Sent from my iPad
> 
> On Jun 19, 2012, at 7:08 PM, John Abraham <john at velocityaircraft.com> wrote:
> 
>> I forgot to mention thought I was at 1000' when turning final .5 out!
>> 
>> On Jun 19, 2012, at 6:40 PM, Tom Falls <tomfalls6 at gmail.com> wrote:
>> 
>>> Correct me if I'm wrong but I think Brooke got 7.4:1 (1.41 miles is 7445 ft/1000). And John Abraham is worse at 5.4:1 to 6:1 (2.5-2.8 nm is 15,190 to 17,000 ft. Divide that by 2800).
>>> 
>>> Tom
>>> 
>>> Sent from my iPad
>>> 
>>> On Jun 19, 2012, at 5:07 PM, Mark Magee <edjonesbrady at gmail.com> wrote:
>>> 
>>>> Hi John,
>>>> What was your speed, do you recall?
>>>> Is Glide Ratio similar for XLFG as to XLRG gear up?
>>>> 
>>>> Mark
>>>> 
>>>> On Tue, Jun 19, 2012 at 2:46 PM, John Abraham <john at velocityaircraft.com> wrote:
>>>> You should see around 15:1 +/- for building variations with a zero thrust setting and gear up.  I have done a 2.5-2.75 NM glide from 2800 feet back to the runway with a windmilling propeller on an XL before.  (yes engine was out so no additional thrust)  best glide airspeed is 85KCAS at gross.  So L/D will decrease if you are lighter slightly. We cleared the fence by about 5’ or so. 
>>>> 
>>>>  
>>>> 
>>>>                       John
>>>> 
>>>>  
>>>> 
>>>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Mark Magee
>>>> Sent: Tuesday, June 19, 2012 2:56 PM
>>>> 
>>>> 
>>>> To: Velocity Aircraft Owners and Builders list
>>>> Subject: Re: REFLECTOR: Reflector Digest, Vol 87, Issue 104
>>>>  
>>>> 
>>>> I don't have the manual here at work, is the XLFG a 12 to 1 glide ratio with a stopped prop?
>>>> 
>>>> 
>>>> Old Long EZ glided 20 to1 on a stopped prop.
>>>> I told myself I'd never fly the heavies... :(
>>>> Mark Magee
>>>> On Tue, Jun 19, 2012 at 12:44 PM, Brooke Wolf <bwolf1 at tds.net> wrote:
>>>> 
>>>> Steve….Just to be clear, do you mean 9.5 to 1, i.e., 9500 feet forward for every 1000 ft altitude loss?  It looks like mine is nearer 8.5 to 1.  Somehow, somewhere I got the idea it would be 15 to 1!  Maybe that is with a stopped prop.  
>>>> 
>>>>  
>>>> 
>>>> Brooke
>>>> 
>>>>  
>>>> 
>>>>  
>>>> 
>>>>  
>>>> 
>>>> 
>>>> 
>>>> 
>>>> From: steve korney <s_korney at hotmail.com>
>>>> 
>>>> Subject: Re: REFLECTOR: Gliding Distance
>>>> 
>>>> Date: June 19, 2012 1:13:22 PM EDT
>>>> 
>>>> To: Reflector Reflector <reflector at tvbf.org>
>>>> 
>>>> Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>>>> 
>>>>  
>>>> 
>>>> 
>>>> At 85 KIAS @ 6000ft , you have about a 9.5 glide ratio.... What are you expecting to see....?
>>>> 
>>>> 
>>>> Steve 
>>>> 
>>>> > From: bwolf1 at tds.net
>>>> > Date: Tue, 19 Jun 2012 12:26:23 -0400
>>>> > To: reflector at tvbf.org
>>>> > Subject: REFLECTOR: Gliding Distance
>>>> > 
>>>> > I am planning some overwater trips in the near future and the subject of gliding distance naturally comes to mind. I have done some limited test flying with my airplane (XLRG w/Aerocomposite variable pitch prop). The results of my gliding performance are not too good. All tests were done around 6000ft with throttle at idle and wheels up. Here are the results:
>>>> > 
>>>> > 80 KIAS - 900fpm…….. yields a glide performance of 1.38 miles/1000 ft altitude
>>>> > 85 KIAS - 1000fpm……..yeilds a glide performance of 1.41 miles/1000 ft altitude
>>>> > 100 KIAS - 1250fpm …..yields a glide performance of 1.34 miles/1000 ft altitude
>>>> > 
>>>> > As you can see, 85 KIAS appears to be the best glide speed.
>>>> > 
>>>> > I know there may be a big difference in what I tested and what happens in the real world with a windmilling or stopped prop. Have any of you brave test pilots done any testing with a windmilling or stopped prop? What were the results? What kind of glide performance did others get with throttle at idle? Is there anyway to correlate throttle idle glide performance with windmilling or prop stopped performance? What is the best way to stretch a wheels up glide on a Velocity?
>>>> > 
>>>> > I would like to get a discussion going on this and find what others have experienced. Thanks.
>>>> > 
>>>> > Brooke, N108BG, XLRG-5, 145 hours
>>>> > 
>>>> > 
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>>> 
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>> _______________________________________________
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> 
> _______________________________________________
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> 
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