REFLECTOR: Gliding Distance

Mark Magee edjonesbrady at gmail.com
Tue Jun 19 20:40:33 CDT 2012


You boys got me all confused here? Glide ratio: Three to One (F-4 Phantom
II), at Best Glide speed airplane goes three feet forward and goes down 1
foot. Three to One Glide Ratio. You guys are throwing in some trigonometry
that's confusing (possibly frightening) folks? At 10,000' AGL an F4 Phantom
II in flameout at best glide has a 30,000 ft 'cone' below it at which
touchdown (or ejection) will occur. Turns lessen the Three to One.
Fairly simple: if an XLFG clean and stopped prop does a 15 to 1 glide
ratio, then at 10,000' AGL, I have a 150,000'  'cone' below me inside which
my wheels will touch down, turns diminishing the cone. Airplane moves 15
feet forward, and falls 1 foot. 15 to 1 glide ratio.
Fairly simple.

Mark B. Magee
PS (F-4 Phantom II was a template subject of my flight training: proof that
with enough thrust a lead brick can fly!)

On Tue, Jun 19, 2012 at 7:34 PM, Brooke Wolf <bwolf1 at tds.net> wrote:

> Tom
>
> I was using the aviation standard of 6000ft/nautical mile. Admittedly, it
> is more like 6076 feet.  Anyway, using 6000 ft., 1.41 nautical miles is
> 8460 ft.  Hence, 8.4:1 glide ratio.  Man…I like this stuff.  Great
> discussion!  Keep it up.
>
> Brooke
>
>
>
>
>
> *From: *Tom Falls <tomfalls6 at gmail.com>
> *Subject: **Re: REFLECTOR: Reflector Digest, Vol 87, Issue 104*
> *Date: *June 19, 2012 6:40:02 PM EDT
> *To: *Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> *Reply-To: *Velocity Aircraft Owners and Builders list <reflector at tvbf.org
> >
>
>
> 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
>> >
>> >
>> > _______________________________________________
>> > To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>> >
>> > Visit the gallery! www.tvbf.org/gallery
>> > user:pw = tvbf:jamaicangoose
>> > Check new archives: www.tvbf.org/pipermail
>> > Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>> ****
>>
>>
>>
>> _______________________________________________
>> Visit the gallery!  tvbf:jamaicangoose****
>>
>> ** **
>>
>>
>> _______________________________________________
>> To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>>
>> Visit the gallery!  www.tvbf.org/gallery
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>> Check new archives: www.tvbf.org/pipermail
>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html**
>> **
>>
>> ** **
>> ------------------------------
>>
>> No virus found in this message.
>> Checked by AVG - www.avg.com
>> Version: 2012.0.2178 / Virus Database: 2437/5079 - Release Date: 06/19/12
>> ****
>>
>> _______________________________________________
>> To change your email address, visit
>> http://www.tvbf.org/mailman/listinfo/reflector
>>
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>> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>>
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
>
>
>
> *From: *Scott Derrick <scott at tnstaafl.net>
> *Subject: **Re: REFLECTOR: Reflector Digest, Vol 87, Issue 104*
> *Date: *June 19, 2012 6:50:49 PM EDT
> *To: *Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
> *Reply-To: *Velocity Aircraft Owners and Builders list <reflector at tvbf.org
> >
>
>
>  That sounds way to exciting John!
>
> -------- Original Message --------
> Subject: Re: REFLECTOR: Reflector Digest, Vol 87, Issue 104
> From: John Abraham <john at velocityaircraft.com> <john at velocityaircraft.com>
> To: 'Velocity Aircraft Owners and Builders list' <reflector at tvbf.org><reflector at tvbf.org>
> Date: 06/19/2012 01:46 PM
>
> 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<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
> >
> >
>
>
>
> _______________________________________________
> To change your email address, visit
> http://www.tvbf.org/mailman/listinfo/reflector
>
> Visit the gallery!  www.tvbf.org/gallery
> user:pw = tvbf:jamaicangoose
> Check new archives: www.tvbf.org/pipermail
> Check old archives: http://www.tvbf.org/archives/velocity/maillist.html
>
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