Today's Message Index:
----------------------
1. 04:11 AM - VGs (Jay Parker)
2. 05:39 AM - Re: VGs (Ken Arnold)
3. 06:21 AM - Re: VGs (MacDonald Doug)
4. 07:54 AM - Re: VGs (Jay Parker)
5. 03:19 PM - Re: Re: VGs (JG)
6. 03:53 PM - Re: Re: VGs (John Bolding)
7. 05:00 PM - Re: vg's (JG)
8. 05:12 PM - Re: Re: VGs (JG)
9. 06:24 PM - Re: Re: VGs (Graeme@cole)
10. 06:42 PM - Re: Re: VGs (Dan Wilde)
Message 1
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But what would happen if you use both kinds of VGs on the same plane......w
ing and elevators?- Again, would that really mess up the flying character
istics of the STOL?- Has anyone tried that before or is one or the other
basically doing the same thing and which is better?- =0A=0AJay
Message 2
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Hey Jay,
Give it a try. Might be interesting. First test would be to see if it
would get airborne.
Let us know how it works.
Regards,
Ken
do not archive
----- Original Message -----
From: Jay Parker
To: zenith701801-list@matronics.com
Sent: Tuesday, July 21, 2009 7:11 AM
Subject: Zenith701801-List: VGs
But what would happen if you use both kinds of VGs on the same
plane......wing and elevators? Again, would that really mess up the
flying characteristics of the STOL? Has anyone tried that before or is
one or the other basically doing the same thing and which is better?
Jay
Message 3
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Sorry Jay, I missed mentioning the elevator VGs on my post last night. The purpose
of the VGs on the elevator is to keep the airflow attached at high elevator
angles of attack. On the elevator, this is during the flare for landing.
The VGs are installed in such a way that they do not actually see the airflow
duing straight and level flight. As the stick is pulled back during the flare,
the nose of the elevator drops down into the airstream and the installed VGs
then keep the airflow attached to the skin of the elevator. This essentially
gives far better elevator control during the flare.
Essentially, what I am saying is that VGs on the elevator have nothing to do with
the VGs on the wings so therefore, it is quite acceptible to use both. I plan
on using the slats on the wings and VGs on the elevator.
Doug MacDonald
CH-701 Scratch Builder
NW Ontario, Canada
Final Assembly
Do Not Archive
--- On Tue, 7/21/09, Jay Parker <zeus45601@yahoo.com> wrote:
> From: Jay Parker <zeus45601@yahoo.com>
> Subject: Zenith701801-List: VGs
> To: zenith701801-list@matronics.com
> Received: Tuesday, July 21, 2009, 6:11 AM
> But what
> would happen if you use both kinds of VGs on the same
> plane......wing and elevators? Again,
> would that really mess up the flying characteristics of the
> STOL? Has anyone tried that before or is one or the
> other basically doing the same thing and which is
> better?
>
> Jay
__________________________________________________________________
The new Internet Explorer 8 - Faster, safer, easier. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/
Message 4
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Thanks.- That makes a lot of sense to me now that I think about it.- Ap
preciate your insight.=0A=0AJay=0A=0A=0A=0A=0A_____________________________
___=0AFrom: MacDonald Doug <dougsnash@yahoo.com>=0ATo: zenith701801-list@ma
tronics.com=0ASent: Tuesday, July 21, 2009 9:19:08 AM=0ASubject: Re: Zenith
ug <dougsnash@yahoo.com>=0A=0A=0ASorry Jay, I missed mentioning the elevato
r VGs on my post last night.- The purpose of the VGs on the elevator is t
o keep the airflow attached at high elevator angles of attack.- On the el
evator, this is during the flare for landing.- The VGs are installed in s
uch a way that they do not actually see the airflow duing straight and leve
l flight.- As the stick is pulled back during the flare, the nose of the
elevator drops down into the airstream and the installed VGs then keep the
airflow attached to the skin of the elevator.- This essentially gives far
better elevator control during the flare.=0A=0AEssentially, what I am sayi
ng is that VGs on the elevator have nothing to do with the VGs on the wings
so therefore, it is quite acceptible to use both.- I plan on using the s
lats on the wings and VGs on the elevator.=0A=0ADoug MacDonald=0ACH-701 Scr
atch Builder=0ANW Ontario, Canada=0AFinal Assembly=0A=0ADo Not Archive=0A
=0A--- On Tue, 7/21/09, Jay Parker <zeus45601@yahoo.com> wrote:=0A=0A> From
: Jay Parker <zeus45601@yahoo.com>=0A> Subject: Zenith701801-List: VGs=0A>
:11 AM=0A> But what=0A> would happen if you use both kinds of VGs on the sa
me=0A> plane......wing and elevators?- Again,=0A> would that really mess
up the flying characteristics of the=0A> STOL?- Has anyone tried that bef
ore or is one or the=0A> other basically doing the same thing and which is
=0A> better?- =0A> -=0A> Jay=0A=0A=0A=0A- - - ___________________
_______________________________________________=0AThe new Internet Explorer
=AE 8 - Faster, safer, easier.- Optimized for Yahoo!- Get it Now for Fr
============
Message 5
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Gday All,
JG from Stolspeed chipping in here. I'm still around and still testing and
comparing STOL wings. Whenever I hear claims and statements I just have to
do tests to see if they stand up. I'm a curious experimenter first and
foremost. I started out very sceptical of VGs, but curiousity led me to try
them, and the results led to manufacturing them. Since so many of you out
there are sceptics, it's a small business, and pretty much just supports
further work in experimenting and testing. The results often disprove
commonly held opinions and open new possibilities, which is really exciting
and worthwhile for an experimental engineering type like me. This is what
drives me to do this work, not the business of selling VGs. I'm no
salesman, just an enthusiast. I'm retired with enough to get by, and this
business is just a means to support all the research. Some of the results
of that research has already been very useful to others who are open to
change.
I've just finished another round of extensive testing of a Savannah with
slats, without slats, and with their 'VG' leading edge, and further tests
loaded with sand bags to max gross weight. Many hours of climb at full
power for 1000 ft, followed by engine off prop-stopped glide back down the
1000 ft, timed with a stopwatch, over a range of speeds from 40 to 70 kts.
Have to do it all at sunrise to avoid thermal activity, and do several runs
at each speed to eliminate spurious readings. It gets tedious, but the
results are enlightening and useful. I used several hundred dollars of fuel,
and a lot of hard work for the engine, just on this last series.... I just
finished that work yesterday, so it's going to take a little awhile to
analyse and compile all the data, then I'll write it up and publish for all
to use to make your own decisions. This was done on a Savannah, but
identical airfoil to the 701, so the results are very useful. I'll let you
know when it's ready.
Some of the prelimary results are ready, and attached is a graph of the
climb rates for Slats vs VGs. Note that the climb rates for each
version below 40 kts are pretty much the same, so the Angle of Climb will be
pretty much the same, contrary to claims elsewhere. Above 40 kts the
difference is really significant. These are real life results not just
claims, so take what you will from them.... More to come later.
JG
On Tue, Jul 21, 2009 at 1:44 PM, MacDonald Doug <dougsnash@yahoo.com> wrote:
> dougsnash@yahoo.com>
>
>
> Jay, check out John Gilpin's (JG) website, www.stolspeed.com With all due
> respect to JG, keep in mind that he is selling something when you read his
> site.
>
>
Message 6
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Hi John, Wish you were coming to OSH again this year, we could
continue the short visit we started when you were here.
As always I enjoy your testing, do you have any theory on why the spread
widens at higher speeds? 200fpm is pretty substantial.
LO&SLO John Bolding
----- Original Message -----
From: JG
To: zenith701801-list@matronics.com
Sent: Tuesday, July 21, 2009 5:17 PM
Subject: Re: Zenith701801-List: Re: VGs
Some of the prelimary results are ready, and attached is a graph of
the climb rates for Slats vs VGs. Note that the climb rates for each
version below 40 kts are pretty much the same, so the Angle of Climb
will be pretty much the same, contrary to claims elsewhere. Above 40
kts the difference is really significant. These are real life results
not just claims, so take what you will from them.... More to come
later.
JG
Message 7
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Yeh Mark, I'm glad you raised that engine off prop-stopped issue. Contrary
to what is often stated, the glide ratio is much less with the engine
stopped than idling. Everyone should be aware of that in case of a real
engine out!
Everyone should try it sometime, so that you're prepared for the
sensation of the sudden quiet, the different feel of the controls, and the
steeper attitude required to maintain safe speed. If it catches you by
surprise sometime at a lower altitude, it could be unsettling enough to
cause a loss of control.... From 3000 AGL, set up a glide at 50 kts, and
note the descent rate with engine at idle, then switch off the engine and
notice the difference in nose-down attitude required to maintain the same
airspeed. It's a strange experience to hear the wind rushing by, and to
be 'flying' the aircraft like a glider rather than just 'driving' along
behind the engine. The glide is very stable if you keep the airspeed
correct, and the silence is so enjoyable that it becomes a bit addictive!
But a couple of tips - As soon as the engine has stopped, switch the mags
back on so it's all ready when you want to re-start. If you don't, sure as
heck you'll try to restart with them off, and then when it doesn't start
right away you will get a fright..... And do it on a calm day over a long
airstrip with no circuit traffic, just in case the starter motor decides to
fail.......
Try it, it's a valuable experience, and a lot of fun.
JG
> Also did an engine off approach (prop stops on a Rotax 912) to a full
> stop landing, wanted to see if the glide ratio was any different than with
> the engine at idol and prop turning. I did not do a four direction glide to
> compensate for any wind, this morning I could not detect any wind. It sank
> at a higher rate than with the prop turning. This is contrary to what I
> have been told. The only thing I can think is that at idol the prop on a
> Rotax 912 is turning enough that it helps with the glide. There was a
> considerably steeper nose down attitude with the prop stopped than with it
> turning at the same air speed.
>
> Mark S.
>
>
> *
>
> *
>
>
Message 8
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Gday John,
Yeh, maybe someday I might get back to OSH but don't know when...
Yeh, I think the spread increases because the drag of the slats increases
with the square of the airspeed. All that difference isn't due to lift, but
rather to drag. The reduction in drag allows all that spare power to go
into climb instead.
Cheers,
JG
On Wed, Jul 22, 2009 at 8:53 AM, John Bolding <jnbolding1@teleshare.net>wrote:
> Hi John, Wish you were coming to OSH again this year, we could continue
> the short visit we started when you were here.
>
> As always I enjoy your testing, do you have any theory on why the spread
> widens at higher speeds? 200fpm is pretty substantial.
> LO&SLO John Bolding
>
> ----- Original Message -----
> *From:* JG <vgstol@bigpond.net.au>
> *To:* zenith701801-list@matronics.com
> *Sent:* Tuesday, July 21, 2009 5:17 PM
> *Subject:* Re: Zenith701801-List: Re: VGs
>
>
> Some of the prelimary results are ready, and attached is a graph of the
> climb rates for Slats vs VGs. Note that the climb rates for each
> version below 40 kts are pretty much the same, so the Angle of Climb will be
> pretty much the same, contrary to claims elsewhere. Above 40 kts the
> difference is really significant. These are real life results not just
> claims, so take what you will from them.... More to come later.
>
> JG
>
>>
>
>
> *
>
>
> *
>
>
Message 9
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| From: | "Graeme@cole" <graeme@coletoolcentre.com.au> |
do not archive
approx a week ago there was alink to zenith and alloy VG's for elevator
alloy CH701.
could some one repost
Thanks Graemecns
Message 10
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ronlee wrote:
>
> That is very nice of John G. at Stolspeed to offer to replace broken VGs.
> I have them on my 701( no slats) and they perform excellent. I wouldn't go back
to slats on a bet. It's just a much easier plane to fly.
>
> --------
> Ron Lee
> Tucson, Arizona
>
>
>
Jeez. I didn't know my plane was hard to fly.
Dan Wilde
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