Today's Message Index:
----------------------
1. 02:07 PM - Re: RV-10 Glide Ratio (rv10flyer)
2. 02:10 PM - Re: Re: RV-10 Glide Ratio (Kelly McMullen)
3. 02:15 PM - Re: Re: RV-10 Glide Ratio (Kevin Belue)
4. 02:23 PM - Re: Re: RV-10 Glide Ratio (Dave Saylor)
5. 05:01 PM - Re: RV-10 Glide Ratio (rv10flyer)
6. 09:09 PM - Re: RV-10 Glide Ratio (Bob Turner)
7. 10:31 PM - Re: Re: RV-10 Glide Ratio (Dave Saylor)
8. 11:12 PM - Re: RV-10 Glide Ratio (Bob Turner)
Message 1
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| Subject: | Re: RV-10 Glide Ratio |
Solo, 40 gal, prop at coarse pitch, rpm 640 and airspeed 80 kias today, I was getting
about 10:1.
--------
Wayne G.
SB 12/01/2009-12/01/2011
TT= 103
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402344#402344
Message 2
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| Subject: | Re: RV-10 Glide Ratio |
Usually best glide is much closer to Vy or even above Vy. I would expect
it to be somewhere between 90&100kts.
On 6/9/2013 2:06 PM, rv10flyer wrote:
>
> Solo, 40 gal, prop at coarse pitch, rpm 640 and airspeed 80 kias today, I was
getting about 10:1.
>
> --------
> Wayne G.
> SB 12/01/2009-12/01/2011
> TT= 103
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=402344#402344
>
>
-----
No virus found in this message.
Checked by AVG - www.avg.com
Message 3
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| Subject: | Re: RV-10 Glide Ratio |
Shut off the engine and the glide ratio will be lower. Stop the prop and it'll
be better.
Sent from my iPhone
On Jun 9, 2013, at 4:06 PM, "rv10flyer" <wayne.gillispie@gmail.com> wrote:
>
> Solo, 40 gal, prop at coarse pitch, rpm 640 and airspeed 80 kias today, I was
getting about 10:1.
>
> --------
> Wayne G.
> SB 12/01/2009-12/01/2011
> TT= 103
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=402344#402344
>
>
>
>
>
>
>
>
>
>
Message 4
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| Subject: | Re: RV-10 Glide Ratio |
Are there two terms for best glide like there are for best climb? Bob
Turner expounded on this a few weeks ago but I'll admit I didn't pay close
enough attention. One would be to get you the furthest, another to keep you
aloft for the greatest duration...or are they the same thing?
I changed my emergency checklist a few years ago from 80 (KIAS) to 95 for
best glide because it seemed that 95 got me further. But earlier I was
pretty sure that 80 gave me the minimum sink rate. Bob??
On Sunday, June 9, 2013, Kelly McMullen wrote:
>
> Usually best glide is much closer to Vy or even above Vy. I would expect
> it to be somewhere between 90&100kts.
>
> On 6/9/2013 2:06 PM, rv10flyer wrote:
>
>>
>> Solo, 40 gal, prop at coarse pitch, rpm 640 and airspeed 80 kias today, I
>> was getting about 10:1.
>>
>> --------
>> Wayne G.
>> SB 12/01/2009-12/01/2011
>> TT= 103
>>
>>
>>
>>
>> Read this topic online here:
>>
>> http://forums.matronics.com/**viewtopic.php?p=402344#402344<http://forums.matronics.com/viewtopic.php?p=402344#402344>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
>
>
--
Dave Saylor
831-750-0284 CL
Message 5
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| Subject: | Re: RV-10 Glide Ratio |
I also keep my TT AP "Min Airspd" set at 80 kts. If one has a lot of altitude it
might help out and keeps us from stalling in an AP climb. With an actual engine
out, we would gain a little more by opening the throttle. If I was at gross
weight, I would shoot for 90 kts.
--------
Wayne G.
SB 12/01/2009-12/01/2011
TT= 103
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402358#402358
Message 6
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| Subject: | Re: RV-10 Glide Ratio |
Minimum sink speed (maximum time before you hit the ground) is not the same as
best glide (cover maximum horizontal distance before you hit the ground).
Minimum sink speed is at the "minimum power required" speed, and in most single
engine GA airplanes is close to Vx and often just a few knots faster than stall
speed Vs1.
Best glide speed in an ideal airplane is greater than Vy, but in every real certified
GA single that I've been in the reverse is true. This is because virtually
all aircraft have cruise props, and the increasing prop efficiency as speed
increases in the Vy speed range pushes real world Vy to higher values.
Best glide (no wind) occurs at max L/D angle of attack. Therefore, it varies with
weight (variation is as the square root of the weight, so, approximately, if
you are under gross by 20%, then best glide is reduced (from gross weight number)
by 10%.). At Wayne's weight I'd say 80 kias is about right.
In the real world, where you want to cover distance over the ground in a glide,
the wind can come into play. With a tailwind, you want to go slower than published
best glide speed, but never slower than minimum sink. With a headwind, increase
speed, roughly by 40% of the wind speed if known.
As a side note, in many training situations where the cfi pulls the throttle and
says "make the runway", the decrease in best speed because you are below gross
weight and the increase in best glide because of the headwind tend to cancel
out.
--------
Bob Turner
RV-10 QB
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402366#402366
Message 7
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| Subject: | Re: RV-10 Glide Ratio |
So am I right in thinking that if you had an AOA indicator, and were able
to glide at L/Dmax, then you could reduce speed on final to increase sink
and not overshoot the landing spot?
For that matter you could also *increase* speed to increase sink, but then
you'd touch down going faster.
Dave Saylor
831-750-0284 CL
On Sun, Jun 9, 2013 at 9:07 PM, Bob Turner <bobturner@alum.rpi.edu> wrote:
>
> Minimum sink speed (maximum time before you hit the ground) is not the
> same as best glide (cover maximum horizontal distance before you hit the
> ground).
> Minimum sink speed is at the "minimum power required" speed, and in most
> single engine GA airplanes is close to Vx and often just a few knots faster
> than stall speed Vs1.
> Best glide speed in an ideal airplane is greater than Vy, but in every
> real certified GA single that I've been in the reverse is true. This is
> because virtually all aircraft have cruise props, and the increasing prop
> efficiency as speed increases in the Vy speed range pushes real world Vy to
> higher values.
>
> Best glide (no wind) occurs at max L/D angle of attack. Therefore, it
> varies with weight (variation is as the square root of the weight, so,
> approximately, if you are under gross by 20%, then best glide is reduced
> (from gross weight number) by 10%.). At Wayne's weight I'd say 80 kias is
> about right.
>
> In the real world, where you want to cover distance over the ground in a
> glide, the wind can come into play. With a tailwind, you want to go slower
> than published best glide speed, but never slower than minimum sink. With a
> headwind, increase speed, roughly by 40% of the wind speed if known.
>
> As a side note, in many training situations where the cfi pulls the
> throttle and says "make the runway", the decrease in best speed because you
> are below gross weight and the increase in best glide because of the
> headwind tend to cancel out.
>
> --------
> Bob Turner
> RV-10 QB
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=402366#402366
>
>
Message 8
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| Subject: | Re: RV-10 Glide Ratio |
Dave,
Yes that is correct. Typical approach speeds are at or less than best glide, so
if the pilot pulls back on the stick with no power change, then once the transients
die out, he'll be slower and have a steeper approach than before.
--------
Bob Turner
RV-10 QB
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=402372#402372
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