Micro VGs

[hilltop170]

I'm surprised Richard with all your experience you haven't flown VGs and experienced them for yourself.

I have flown VGs a lot but not on a Cessna wing. I owned a Super Cub and flew it several years without them and several years with them. It made a huge difference on the Cub wing. Before VGs, full flap stall speed was 42mph indicated. After VGs, full flap stall speed was 20mph indicated and it had a rock steady approach at 40mph indicated. I have no idea what actual airspeeds were but an improvement in angle of attack of that magnitude was impressive.

I agree in theory, VGs will work to some degree or other on any wing but the type of wing determines how effective VGs will be. The thick Cub high lift/high drag wing benefits greatly. It looks like Willie had the same improvement with the Champ wing. However, I have never seen any data or evidence VGs would have anywhere near that kind of improvement on a Cessna wing, especially if it already has a Sportsman or other STOL kit and/or extended wings.

I suppose I would also say "oh boy, it really flies better now" if I had spent that much money on a mod whether it did any good or not. The difference is I would get the data before and after so I would know one way or the other for sure. Chuck White doesn't include any data that I can find on his website and nobody I have ever talked to has done any flight testing before and after on Cessnas like we are flying.

I am not trying to cause any controversy, I'm just asking for any evidence one way or the other. I have not seen any and if you don't care how well they work or don't work then there is no controversy, just spend the money and say "oh boy, it sure flies better now".

[54170b]

Im renting a Cessna 150 to get my pilots liscence in, and the owner asked me to please install them, so I did, and I didn't keep track of airspeeds but I do know that before I could not, and now I can put the yoke in my lap without going into a full stall, and do 360s through it all I want with great control.

[Bruce Fenstermacher]

Richard, I intended to do flight testing before and after. Had some numbers down but then I flew the after test flight with a friend and 170 pilot who at the time had more time in 170s than I did. But what happened is we said "oh boy, it really flies better now", and we couldn't stop smiling enough to write down numbers. Really it was that drastic. Numbers that BTW would not have been accurate due to the extreme angle of attack the plane could fly.

I've not flown a Cub with VGs but can only imagine. I would think the Cessna wing airfoil not being as fat at the Cub, the VGs would make a bigger difference with the Cub. But believe me they improve the flight characteristics and feel and confidence in the pilot in their ability to fly slow with complete control with the Cessna wing.

BTW I've disclosed this before. I didn't pay for my first set of VGs, I won them. I'd tell you if they didn't work. I suppose what might say more is if I'd buy my second set. Perhaps I should.

[sfarringer]

Well, I'm another guy who bought VG's and installed them on my Ragwing 170.
So, since I paid for them I guess I have to like them.

The day I installed them, my mechanic (who also has a Ragwing 170) and I measured stall speed before and after, and also roll rate at 60 mph indicated, before and after. I don't remember the exact numbers. My recollection is that the stall speed did indeed decrease a few mph, and the roll rate improvement was very noticeable. I suspect that they decreased cruise speed a little, but that is harder to tell. I believe that the best angle of climb airspeed is reduced, but do not have before and after data.
Was the airplane a capable airplane before adding the VG's? Yes
Do I think the VG's improved it? Yes

Actually, I like them quite a lot. I expect to be recovering the wings about a year from now. I will be putting a new set on after recovering. So, I will have another chance to measure differences, and write down the data this time! But, I am pretty sure that the people who don't like them now will still not like them then .

[pdb]

I think the real benefit for any 170 stol kit is the low speed handling. I don't think any of them do much for short takeoff performance. They may do something for takeoff but I doubt it, certainly not enough in my opinion to justify them for take off. The benefit comes from keeping you alive if you get too slow. The Horton clearly delays the stall and improves low speed handling. The Sportsman kit, a newer design, appears to be somewhat better than the Horton.

The problem with both the VGs and the Horton kits is that there is no real flight testing available to see which gives you the most bang for the buck. I found that VG guys like VGs, Horton guys like Horton kits, affluent guys like Hortons with VGs and really rich guys like Sportsman kits with VGs. But there is little data, just opinion for our planes. VGs have been used to good effect on jets and larger aircraft. Newer Cessna airfoils have incorporated the larger radius LE of the Horton and Sportsman so neither are snake oil.

Further, I haven't heard any significant criticism of either. I think they all have a good reputation and you would be happy with any.

If I were a rich guy or an A&P, I would have put on a Sportsman kit with VGs on my 170B. You can't do that on 170s or 170as but you might put on the Horton and latter add the VGs if you wanted even more performance.

With regard to my VGs by themselves, I will tell you that after installing VGs, I have never gotten up the nerve to land my 170B in the ultra nose high, slow speed, power on configuration that I am comfortable flying all day in at 2,000 agl with the stall horn blazing. My airspeed gets so slow that I have no idea what my real TAS is. So, the plane has more stol performance that I safely use. However, even with my wimp short field approaches, I can consistently land much shorter than I can take off.

What I would not do is mess with the Horton flap gap kits on the B model. They appear to defeat some of the low speed benefit with the B model flaps. I don't know if the gap seals even fit on either the 170 or A model.

The short story:

1) I think you would be happy with either the Sportsman, Horton or the VG, or both. I think either by themselves would improve your slow speed handling enough to justify the price. I do not think there is any good data to support claims of higher climb or cruise speeds.

2) the effective feature from the Horton is an increased leading edge radius. The Sportsman is similar with a bit of a droop. Cessna adopted a similar mod on later models. Stall fences add some additional benefit to delay the turbulence separation from working out to the tips.

3) VGs work completely differently from the enlarged LE radius mod so I think that the combination of VGs and Horton or Sportsman may give you even more benefit.

4) Putting VGs on and then later adding a Horton or a Sportsman is a nightmare as you have to take off then reinstall the teeth on top of the new leading edge.

5) installing VGs is really simple and quick.

6) Neither is going to get you off a beach much quicker.

[GAHorn]

I don't need band-aids to get into/out of the fields I use.

I'd rather be seen with a good-looking, fast girl than an ugly slow one.

VG's are ugly.

[pdb]

I don't need band-aids to get into/out of the fields I use.

I'd rather be seen with a good-looking, fast girl than an ugly slow one.

VG's are ugly.

If you were really interested in flying a good looking airplane, you would strip off that lipstick and fly an all metal bird.

[170C]

I enjoy reading the various comments on these type subjects. Someone once told me that if you asked a guy who just spent $------ on a new vehicle if he liked it, would you expect him to say NO. I have no experience with vg's. Personally I think they detract from the looks of a plane, but if they improve the handling of said airplane then whats not to like. No one mentioned slashed fingers/hands when washing their vg installed planes

When I was negotiating the purchase of Ole Pokey back in 1989, I didn't know much about stol kits, etc (still don't). The owner told me that the Horton stol kit (leading edge, stall fences & aileron gap seals [no flap gap seals]) made the plane handle so much better than without them. Not sure how he knew as he bought the plane with these items already installed One of the first things I noticed was a smaller, second airspeed indicator in the panel. When quizzed about it, he told me it was a helicopter airspeed indicator. He said the plane flew so slow that the factory AS indicator wouldn't indicate any AS That was the first thing that came out of the panel I have always thought the stol slowed the plane down. NO George, its not that its GREEN The plane was blue & silver when I bought it. I have heard other 170 owners say it "does" add drag & thus some reduction in speed while others have said it made no difference in their speeds. Who knows

[HA]

we put VG's on all of our C340's years ago when they first came out. The big draw for us was that particular installation allows you to increase the gross takeoff weight by 300 lbs (makes the vertical tail think it's bigger for SE control certification). But I did do a full set of stalls etc before and after and the numbers pretty much were just as Micro claimed, so we were satisfied with all that too. Not that I ever want any of the guys to be testing out the slow-speed characteristics of the airplanes, that would purely be a safety boost to make up for ham-handedness in engine out situations.

the glue is good, although you can remove the VG's with a careless fuel hose or in our company's case, hail. Just clean the spot and glue another one on, I use a yardstick to line them up and make sure it doesn't end up looking like a conga line down the wing. The worst thing about them is the ones on the inner wing don't allow you to sit there to refuel the locker tanks anymore, a little tough on the seat of your pants.

[GAHorn]

OK... Just to recap this conversation...

Folks who have them like them because they say it improves slow speed handling a lot.

VGs don't measureably improve takeoff performance...but they make the airplane feel more solid right down to a stall, with good aileron feel.



So.., ..why are we flying this slow for long periods that we need this "feel" changed? Isn't the sloppy aileron feel a good thing to warn us that we're too slow?

<joke>"Uh, yeah Doc. Everthang was goin' real good an' then WHAM! I wake up here with you!" <joke>

I mean, ... I land at places so short I can barely get back out of there, and if VGs don't get me back out of there .... why would I need to go slower and feel good about that? Virtually 100% of all places at which I land... I already feel good about. Why would I even want to fill out a form to win a drawing for them?

(No, I'm not trying to stir things up with those who have them and who clearly are glad they have them.... I'm just trying to figure out exactly what performance gain they provided that an unmodified airplane cannot also accomplish? So-far, these little things have worked marvels on high-speed jets and multi-engine Vmc numbers, but what are they really gonna do for a C-145 fixed pitch 170 "family car of the air"?)

(I believe It's a rhetorical question, and would encourage a wondering newbie to spend time practicing piloting skills than looking for magic bullets that likely won't even be on the next plane he flys. His improved skills will work on every plane, most of which do not have the things that feel good at speeds he'll likely never visit and shouldn't be attempting anyway.)

If you already have them, I'd certainly not spend any effort removing them, but if repainting the airplane....

(where's that little emoticon of that little guy stirring a pot..?? )

[Bruce Fenstermacher]

George, it is just something you have to experience to know why you want them and wouldn't remove them if you had them. But no one said you need them. Got it!

[GAHorn]

It was purely rhetorical. I have flown them on an early 182.

[W.J.Langholz]

pot-stirrer.gif (170.05 KiB) Viewed 21849 times

Pot Stirrer



W.

[GAHorn]

What were you cookin' up, Dubya!

[W.J.Langholz]

MMO just for you........oooopppppssss that another one of those topics for a cold winter day and no flying eh.

Happy New Year George, and thanks for all your help n this forum!


W.