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vgstol(at)bigpond.net.au Guest
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Posted: Thu Aug 23, 2007 10:32 pm Post subject: VGs on 701 |
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Boy, the mention of VGs sure does stir up a storm........ <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
That’s really mystifying to me, because I’m just trying to share some really significant discoveries that we’ve found by experience..........
I’ve been in love with the CH701 for about 18 years, but intrigued by the possibility of removing the slats for most of that time, so always watching and studying for evidence in that direction. I certainly didn’t start this as a manufacturer of VGs looking for a market for them on the 701. I was a doubting sceptic before I actually tried them – and you wouldn’t think they’d do much on a wing like the 701, anyhow eh. I was just going to remove the slats, as the Columbians had done, expecting to get better cruise efficiency, and prepared to lose some STOL capability which had lots to spare. I expected maybe 10% improvement in fuel burn, but was amazed to find 23%! STOL performance was less of course, but still adequate for most all practical use. Then, being a curious experimenter, decided to try VGs, and was totally amazed that most all of the STOL capability came back! The more I tried VGs the more I liked the effect that they gave, but I didn’t like the sharp points and the fit to the wing of the ones on the market. And so designed and tested the ‘Feathers’, and so it went from there.......
I certainly didn’t start manufacturing VGs to make a lot of money. Homebuilt aircraft is not a mass market and so many of those builders are complete sceptics, some are even from <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />Missouri..... And only need one set of VGs for an aircraft, then never hear from that one again. If I wanted to make lots of cash flow I’d go for something like lawn mowing – get paid to do it all over again in a couple of weeks. Or for more excitement, get a mobile dog-washing franchise.... I’m semi-retired, and not inspired to make any big business of this, just enough to keep tinkering and experimenting with light STOL aircraft. There’ll be more to come, stay tuned.
Some of us are born experimenters and innovators, and are always interested in trying to make things go better. (I even felt the need to modify my Buck pocket knife....) Others just want to follow the straight and narrow, especially with aircraft – so let it be for them. Surely we can all share this forum without animosity, and encourage the diversity rather than trying to shoot it down...... It’s almost as if it’s considered heresy to even explore alternatives...... This homebuilt aircraft game attracts some really clever and capable minds, and I for one really enjoy sharing constructive ideas and experiences with them. I’ve already met many really interesting and innovative builders online, and it’s just great to have this medium to hear from more of them all over the world. The nay-sayers always seem to shout the loudest, but I know of many builder/flyers out there with heaps of good experience, who speak seldom, and quietly when they do, but are really worth listening to..... It’s heartening to note that the first to be attracted to, and try these changes, were very experienced flyers, who now love their 701s even more since they’ve cut their slats off – surely that says something worth paying attention to.....
I pay most attention to real life experience and evidence, rather than theory or pre-conceived opinions. And I’m ready to change my opinions when I see new evidence. That ‘big wind tunnel in the sky’ is the real test. That’s why I’ve flown 400 hrs in the last two years, always observing and testing these changes we’ve made. And I certainly don’t fly like a Cessna - more like a hawk on a mouse! Always looking for some new challenging spot to practice STOL landings. Just got back from 38hrs of flying into outback Australia, actually using my STOL aircraft to land in very rough and remote places – how many of you really do land your STOL aircraft off-field.... Everything in that website is derived from such experience.
Lastly, there seems to be some misconception of the results I’ve claimed for replacing slats with VGs:
I’m not saying that VGs make for shorter landings than slats, just pretty close to equal STOL performance, with lots of improvement in climb, cruise and glide. The common experience that most flyers notice is an gentler transition from hold-off to touch-down, thus making slower landings easier for the average flyer.
And I certainly don’t encourage anyone to go near Vne, but it sure is good to be able to cruise at 80 kts while burning less fuel than used to at 75, and still have pretty much the same STOL performance. That’s really significant for those of us who actually go cross-country in our aircraft......
I’ve written pretty much all I have to say in the www.stolspeed.com website, and written it as carefully and as completely as I can. I won’t get into a shouting match here, as happens on so many forums. But if there are serious questions that I haven’t covered in the website, I’ll discuss them.
Tailwinds always,
JG
[quote][b]
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cte82621(at)centurytel.ne Guest
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Posted: Fri Aug 24, 2007 5:17 am Post subject: VGs on 701 |
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Juan,
Well said! I am one of those quiet but experienced pilots who decided
long ago that there is nothing out there that can't be improved upon. It
is the spirit of Americans after all , isn't it...
I started my project at kitlog.com/kapowsin about six months ago and
from the get-go ordered it without the leading edge of the wings cut for
slats.
I have heard all of your various viewpoints and appreciate the input.
I bought into the 701 because of the slats and really like the way it
flies with slats, but love the advatages VG's add to it!
Thanks again ,
John E in Kapowsin
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JerryHey
Joined: 05 May 2007 Posts: 30
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Posted: Fri Aug 24, 2007 6:02 am Post subject: VGs on 701 |
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The impression I get is that the slats improve STOL performance when
taking off i.e. high power settings- prop wash. However, when landing
with low or idle power below 50 mph a 701 with slats will sink
rapidly and the elevator may lack the authority to pick up the nose.
The claim is that eliminating the slats and adding VGs to the wing
and elevator restores elevator authority. I am keeping an open
mind. I would like to hear from veteran 701 pilots about power
off, low speed approaches and high sink rates.
P.S. My last airplane, a Tailwind, would not stall until about 50
mph, but sank heavily if the air speed fell below 80 mph. All
Tailwind pilots know to maintain 80mph to the flair or face a gear
bending collision with the runway. Thanks Jerry
On Aug 24, 2007, at 9:15 AM, John C Edwards wrote:
Quote: |
<cte82621(at)centurytel.net>
Juan,
Well said! I am one of those quiet but experienced pilots who
decided long ago that there is nothing out there that can't be
improved upon. It is the spirit of Americans after all , isn't it...
I started my project at kitlog.com/kapowsin about six months ago
and from the get-go ordered it without the leading edge of the
wings cut for slats.
I have heard all of your various viewpoints and appreciate the input.
I bought into the 701 because of the slats and really like the way
it flies with slats, but love the advatages VG's add to it!
Thanks again ,
John E in Kapowsin
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NYTerminat(at)aol.com Guest
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Posted: Fri Aug 24, 2007 7:25 am Post subject: VGs on 701 |
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Jerry,
I can attest to high sink rates at idle below 45 mph. I haven't really found lack of elevator authority though. You definitely need a fair amount of power with a high attitude and slats, it will literally hang on the prop. My last BFR a few weeks ago,my instructor wanted to fly in the 701 and see what it would do. He had me fly hands off using rudder only, right to the airport, do an engine out 180 degree turn to see how much altitude you loose to see if you could make it back to the runway, pull the power near the airport and do an engine out right to the ground. The plane performed well, you need to keep you speed up and fly it right to a few feet above the ground before flaring. Someday I would like to remove the slats and try some VG's, but for now I am having a blast.
Bob Spudis
N701ZX
In a message dated 8/24/2007 10:03:47 A.M. Eastern Daylight Time, jerryhey(at)earthlink.net writes:
Quote: | --> Zenith-List message posted by: Jerry Hey <jerryhey(at)earthlink.net>
The impression I get is that the slats improve STOL performance when
taking off i.e. high power settings- prop wash. However, when landing
with low or idle power below 50 mph a 701 with slats will sink
rapidly and the elevator may lack the authority to pick up the nose.
The claim is that eliminating the slats and adding VGs to the wing
and elevator restores elevator authority. I am keeping an open
mind. I would like to hear from veteran 701 pilots about power
off, low speed approaches and high sink rates.
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Avidmagnum
Joined: 18 Nov 2006 Posts: 19 Location: Wisconsin, Florida
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Posted: Fri Aug 24, 2007 8:45 am Post subject: Re: VGs on 701 |
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I went flying a couple days ago with my 20,000+ hour CFI for by BFR. The last BFR we flew with the slats and he thought the aircraft flew OK as he put it. With the slats off he said it flew much nicer. The handling is just that much better. My 701 is on amphibious floats with a 912s. He had such a good time in the 701 he said he hated to charge me!
The nice thing about Experimental Aircraft is just that....they are experimental! For those that love the slats...leave them alone! For those that are not sure.....experiment....you are only out a little on the price of the VG's. (The ones for my Cessna 170A were $1450...one reason that I only own home builts now!) And you can remove the vg's and put the slats back on....no problem.
I love looking at JG's web site and enjoy our back and forth e-mails. He seems to love what he does! Please keep new ideas coming. I'll look and then "take them or leave them" In my case.... with my situation....I'd have sold my 701 and got a different float plane if the idea to remove the slats would not have been posted here. Thanks!!
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vgstol(at)bigpond.net.au Guest
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Posted: Fri Aug 24, 2007 3:44 pm Post subject: VGs on 701 |
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For those who have tried to access the www.stolspeed.com website recently, the provider was changing servers, so all the new links and photos were missing.
Try again now for details on the Longer Wing and some photos of STOL flying in the Australian outback.
Tailwinds always,
JG
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