Vortex Generators

shortfielder · Post by **shortfielder** » Thu Dec 22, 2005 1:06 pm

Good morning and happy holidays. While I am waiting to find my C-170 I have been wondering about VG's. I was reading about and talking with the man building and selling the landshorter VG's. There maybe discussion here about these alreadyand I just don't know how to find them. So I would like help being able to find previous discussions and/or anyones thoughts on the use of VG's. They sound pretty interesting. And this particular brand is very affordable, if anyone has any experience with them. I realize that they come with no stc. but it sounds like you can do a 337 w/o too much trouble. Thanks Gary

Post by **Bruce Fenstermacher** » Thu Dec 22, 2005 2:26 pm

Gary
The use of VGs as well as other mods to shorten the already pretty short landing characteristics of the 170 have created some of the longest threads of the forum.

To search for those posts look at the top of this page under the title and click on the word Search. Once on that page in the center right in the blank space type VGs or Vortex Generators. Click the search button near the bottom center and your off.

A real short answer to you basic questions.

First one time modifications approved on a 337 can be nearly impossible to get in many parts of the country. Specially for a modification where there is already an STCs product. I wouldn't think of buying VGs that weren't STCd for my aircraft.

Second. I have Micro Air VGs that are STCd for my 170. I won them as a door prize so i have no financial investment. I like them because what I think they allow me to do with the 170 is fun. I don't need them for the type of flying I do.

They can be a pain if you wash your airplane, I never do. It is much more difficult to clean ice and snow off the wings in the winter without cleaning off the VGs as well.

There are about 30 other modifications I might buy before VGs for my air craft if I had to pay for them.

shortfielder · Post by **shortfielder** » Thu Dec 22, 2005 3:21 pm

Now I know how to search topics. I read the posts on the VG's/STOL kits. Very interesting. Happy holidays Gary

N2865C · Post by **N2865C** » Thu Dec 22, 2005 4:02 pm

search tip:

If you are looking for info on vortex generators, search for "vortex and generators" (no quotes). That way you will only get posts with the words vortex and generators in them. Otherwise you will also get all of the posts about generators, as well as any with the word vortex (for example -wingtip vortex)

zero.one.victor · Post by **zero.one.victor** » Fri Dec 23, 2005 2:08 am

Bruce, I was wondering if you can give us a quick and dirty version of your before-and-after impressions of the Micro VG's?
In spite of having never flown anything with either mod, I am of the opinion that some wing designs are more responsive to the addition of VG's, and some more responsive to the addition of a traditional STOL kit (leading edge cuff, etc).
From what I've heard and read, the Cessna wing benefits more from a STOL cuff, while the Cub and similar airplanes do better with the vortex jiggers. Sounds like one of the better aspects of these mods is not so much any lowering of stall speed, but increased control effectiveness and feel allowing for more confidence operating at lower (approach) speeds.

Eric

shortfielder · Post by **shortfielder** » Fri Dec 23, 2005 2:16 am

Bruce/Eric From what I am hearing and reading I am coming to the conclusion that you use a stol kit to lower the stall speed, shorten landing/takeoff distances. You use the VG's to get more/better control from your control surfaces at these slower speeds. Sound reasonable? Gary

lowNslow · Post by **lowNslow** » Fri Dec 23, 2005 5:00 pm

If you believe their marketing, Microaero claims 10% reduction in stall speed AND improved handling.
http://www.microaero.com/

Post by **Bruce Fenstermacher** » Fri Dec 23, 2005 7:14 pm

Eric and Gary

You may have hit the nail on the head. I believe the control effectiveness is greatly improved at slow speeds and so it is very comfortable to fly slow. I also believe the stall speed is reduced. This of course is on my 170 which I flew with and without them.

I've not flown ay other aircraft with them so I can't comment from personal experience but have heard that a Cub with them will go REALLY slow.

As for takeoff in my experience VGs alone won't get you off the ground sooner but when you manage to get the aircraft airborne the controls will feel very comfortable at the slowest of airspeeds.

We've really rung this discussion out on many a past thread where I as well as others have given our experience with VGs as well as wing cuff type stol kits.

CraigH · Post by **CraigH** » Fri Dec 23, 2005 7:26 pm

lowNslow wrote:If you believe their marketing, Microaero claims 10% reduction in stall speed AND improved handling.
http://www.microaero.com/

I've never flown a VG equipped 170, but do have around 100 hours in a MicroAero VG equipped TriPacer. They had a noticeable difference in the TriPacer. Very comfortable in slow flight, and more aileron authority close to the stall.

Fri Dec 23, 2005 11:12 pm

That is what you get with a 170 as well. The airfoil of a Tripacer is nearly the same as a Cub.

Some have argued they don't reduce the stall speed but I think differently. Even if they don't reduce the stall speed, you can fly with confidence right down to stall so you will find yourself using a much slower approach speed than you would without VGs.

doug8082a · Post by **doug8082a** » Sat Dec 24, 2005 12:06 am

Just thinking out loud for a moment, but do you think that, perhaps for the less experienced pilot, the addition of VGs could actually be a bit dangerous? STOL kits obviously do an hoenst job of reducing stall speed. However, if VGs really only improve handling down to the regular stall speed, then I would think that the inexperienced pilot would be lulled into a false sense of security. Mushy controls are one sure sign of approaching stall speed and if that indicator is not there then they might fly right down to the point where the plane quits flying altogether.

Post by **Bruce Fenstermacher** » Sat Dec 24, 2005 1:19 am

You are assuming the plane actually stalls Doug.

If you reread my opinion I say VGs DO reduce stall speed.

I have done enough flight testing to satisfy me that it does what is advertised. However those tests weren't done under any regiment before and after the installation that could be used o prove to skeptics that it works.

Next time we have a get together Doug or anyone for that matter, we'll just have to take it around the patch and you can decide for yourself what the VGs do and don't do.

doug8082a · Post by **doug8082a** » Sat Dec 24, 2005 3:07 am

You're on! I'd love to have a go at them!

blueldr · Post by **blueldr** » Sat Dec 24, 2005 4:02 am

I believe a set of STCd VGs cost about $1400.
Non STCd VGs cost about $100
I would suggest installing a set of non STCd VGs and see if you think VGs are worth installing on a Cessna wing.
You just might save yourself $1300!
If you like them, you can buy the STCd set and become legal.
Sell the bootleg set to somebody with a homebuilt or to a pirate like me, though I wouldn't have them on my plane. I don't think they're worth the effort to install and maintain them and I don't think they do squat for the Cessna wing.

shortfielder · Post by **shortfielder** » Sat Dec 24, 2005 4:20 am

Along with all this I wondered if anyone has heard any pros and cons of any particular brands. I had heard from one man that he thought that the ones mounted further back on the wing worked better. Also I haven't checked prices except for the non stc'd ones which were $100. But I did talk with a guy that put them on a maule and he liked them ad said they were around $600. and took about a 12 pack to put on with a friend. Gary

The International Cessna^® 170 Association

Vortex Generators

Vortex Generators

Thanks Bruce

Vortex generators/stol kits

pros and cons