MicroAero Vortex Generators

[Lawreston]

Has anyone had any experience flying with the vortex generators from MicroAero(out in Tom Downey territory)? I'm thinking about having them installed on my new plane. "Testimonials" read well, but are they actually testimonials? http://www.microaero.com/

HR

 

[Shipoke]

Buddy put them on his Cherokee 140 ,i didnt see much differance around here,In Pa Dave G

 

[DeeG]

We put them on both the Stinson and the C-150. Landing speed on the 150 was down to about 28 mph, typical approach speeds are about 5mph slower now. Both the planes feel a whole lot 'stabler' now as well. On Pete's last BFR, he couldn't get the plane (Stinson) to stall. I'm sure it would have, but the CFII didn't feel comfortable doing aerobatic type manuvers to make it happen. He said the plane felt like it was hanging by the prop, and still nothing happened, no buffet.

Pete says any plane he gets, VG's will be one of the first things that go on it. Says they are worth every penny. Easy to install, as well.

 

[Lawreston]

Thanks for the answers, thus far.
Dee: I wonder what would be any resulting change(s) if I were to install the Power Flow Tuned Exhaust system(the new short stack version) and Vortex Generators. P-F decreases take-off roll(allegedly), so when combined with VG(s).............??????????

HR

 

[Dave Krall CFII]

Good reports of performance increase/$ from flyers in PacNW that I've read.

 

[Henning]

Thanks for the answers, thus far.
Dee: I wonder what would be any resulting change(s) if I were to install the Power Flow Tuned Exhaust system(the new short stack version) and Vortex Generators. P-F decreases take-off roll(allegedly), so when combined with VG(s).............??????????

HR

One thing about using the tuned exhaust, in order to get maximum benefit from it, you'll need to re pitch your prop a bit. The VGs are typically a good thing. If you really want STOL performace, then look at one of the good STOL kits as well.

 

[wsuffa]

We put them on both the Stinson and the C-150. Landing speed on the 150 was down to about 28 mph, typical approach speeds are about 5mph slower now. Both the planes feel a whole lot 'stabler' now as well. On Pete's last BFR, he couldn't get the plane (Stinson) to stall. I'm sure it would have, but the CFII didn't feel comfortable doing aerobatic type manuvers to make it happen. He said the plane felt like it was hanging by the prop, and still nothing happened, no buffet.

Pete says any plane he gets, VG's will be one of the first things that go on it. Says they are worth every penny. Easy to install, as well.

My experience on the Commander is similar to Pete's. Power-on stalls didn't happen below about 25-30-degrees nose-up. It hangs there. I got slow flight down so far that ATC/flight following asked me how I got it so slow.

Saved my bacon one time. That's a different story.

 

[AdamZ]

Do I assume correctly that insallation of VGs while decreasing stall speed also create drag which would slow a plane down in cruise. If so it would make sense for those flying in and out of short fields but you wouldn't want to put one on a plane like a Tiger or Diamond with Laminar airflow?
Is this correct?

 

[gismo]

Do I assume correctly that insallation of VGs while decreasing stall speed also create drag which would slow a plane down in cruise. If so it would make sense for those flying in and out of short fields but you wouldn't want to put one on a plane like a Tiger or Diamond with Laminar airflow?
Is this correct?

My experience with VG's is that any impact on cruise speed is minimal, at least on a not so laminar flow wing like my Baron has. One other note is that IME, the drop in indicated stall speed is much greater than the actual drop in calibrated stall speed.

 

[Dave Krall CFII]

Do I assume correctly that insallation of VGs while decreasing stall speed also create drag which would slow a plane down in cruise. If so it would make sense for those flying in and out of short fields but you wouldn't want to put one on a plane like a Tiger or Diamond with Laminar airflow?
Is this correct?

Some of these micro vortex generators are vehemently said to NOT decrease cruise speed, so must be somehow deceasing drag in that speed range while increasing lift at stall ranges ?

 

[wsuffa]

Some of these micro vortex generators are vehemently said to NOT decrease cruise speed, so must be somehow deceasing drag in that speed range while increasing lift at stall ranges ?

Any decrease on my plane was not noticable.

What some folks have told me, though, is that the increased lift on the tail feathers may be slightly more or less than the increased wing lift, causing you to have a somewhat different trim point, causing a bit more drag.

 

[Dave Krall CFII]

Any decrease on my plane was not noticable.

What some folks have told me, though, is that the increased lift on the tail feathers may be slightly more or less than the increased wing lift, causing you to have a somewhat different trim point, causing a bit more drag.

One micro vortex manufacturer actually claims a slight INCREASE in cruise speed. If true, I think they must set up some partial laminar flow or somehow reduce drag slightly at that higher speed.

 

[MauleSkinner]

The reason that the VG's "don't decrease cruise speed" is that technically they're within the boundary layer of the wing, where airflow isn't as fast anyway.

They're also not supposed to collect ice, but I've seen ice on 'em...of couse, that was when I got 4 inches in under 2 minutes, so it mighta' been an exception

Fly safe!

David

 

[DeeG]

Thanks for the answers, thus far.
Dee: I wonder what would be any resulting change(s) if I were to install the Power Flow Tuned Exhaust system(the new short stack version) and Vortex Generators. P-F decreases take-off roll(allegedly), so when combined with VG(s).............??????????

HR

Not sure H. I would assume, yes.

When Pete and I took the Stinson to FL a couple of years ago, we parked the plane at Ocala. I saw a C-177 sitting on the ramp and went to go drool on it (I WANT a Cardinal...) The owner came up and we started chatting and he asked me if I wanted to fly it around the patch a few times. HECK YEAH!! It was a 150 HP, and after hearing all the negative things about the plane (anemic power, crappy handleing), I was surprised at the power that the plane had. Two of us on board, plus I think he had just fueled it up. I was a muggy October day, but the plane practically lept off the runway. After we landed I had asked him about the strange looking exhaust on the plane. He said it was one of the Power Flow exhausts. He raved about it. In fact, I think it was the first 150 HP 177 that PowerFlow did and was featured on their website for quite some time (the plane was green). I don't see it there any longer, unless the plane has been painted since 2001.

If one were available for the Stinson, I would be one of the first in line to get one. (Hmmm...maybe they want a test bed plane???)

you may want to chat with them about it.

Dee

...snip... One other note is that IME, the drop in indicated stall speed is much greater than the actual drop in calibrated stall speed.

Lance, the drop in stall speed was measured by GPS. We had used the GPS in the past under almost the same conditions (two on board, full fuel, same weather) BEFORE we installed the VG's. Then a few days after the VG's were installed we did 'landing practices' again. This time, the airspeed was at least 5 mph slower on the GPS than the GPS speeds before the VG's were installed. (We did this because Pete wanted a benchmark speed with which to test the claims of the VG manufacturer, and we spent two hours each time doing t/l & landings). I hate having to do any math to get a calibrated speed, and besides, I use the a/s indicator like I use the speedo on my land based vehicles: they are a guesstimate 9within a certain percentage) as to my true speed. My Honda motorcycles have a 10% speedo error above 25 mph. The speedo will read 10% higher than what the GPS is telling.

 

[gismo]

Lance, the drop in stall speed was measured by GPS. We had used the GPS in the past under almost the same conditions (two on board, full fuel, same weather) BEFORE we installed the VG's. Then a few days after the VG's were installed we did 'landing practices' again. This time, the airspeed was at least 5 mph slower on the GPS than the GPS speeds before the VG's were installed. (We did this because Pete wanted a benchmark speed with which to test the claims of the VG manufacturer, and we spent two houroed, and besides, I use the a/s indicator like I use the speedo on my land based vehicles: they are a guesstimate 9within a certain percentage) as to my true speed. My Honda motorcycles have a 10% speedo error above 25 mph. The speedo will read 10% higher than what the GPS is telling.

Actually a 5 mph drop sounds plausible (I thought you saw a 9 mph drop in IAS though). Also WRT GPS speed differences, how did you account for the wind?

 

[DeeG]

Actually a 5 mph drop sounds plausible (I thought you saw a 9 mph drop in IAS though). Also WRT GPS speed differences, how did you account for the wind?

Wind direction was the same as the first flight, wind speed was within 2kts. It was a typical summer day in Wenatchee, warm and calm.