VG installation with STOL kit

[Bruce Fenstermacher]

BTW the little video of my short landing at Petit Jean is an example of what just happens when you have VGs. I wasn't particularly trying to land short for that landing. The approach speed I was using just felt right and it was slow but I never looked at my airspeed indicator. It all just came together and happened to be caught on camera.

[buzzlatka]

As george said there has been no real talk or video of takeoff performance increases with the VGs. I can already land the airplane very short. Most of the times around 40 to 50 indicated depending on weight. The takeoff is what I am interested in . I already takeoff and climb over the trees with zero indicated airspeed. I know that increasing weight in increments of 100lbs adds about 50 ft to the liftoff point and gets me about 10ft lower crossing the trees. I would be very interested to see whether the VG's can allow the airplane to lift off and climb at higher AOA's on takeoff. I suspect they do. Maybe I just need to go install them and redo my performance data with them on. I already have very detailed takeoff performance data for my 170 on the strip for lower takeoff weights with temps ranging from 50 to 85 degrees F. I could then get them for the VGs and settle this topic once and for all.

[Bruce Fenstermacher]

VGs won't get the plane off the runway any quicker because your rotation is limited until the wings lift the mains off the ground. You can increase the AOA with taller tires or taller main gear. Once in the air and at a high AOA VGs will increase control response making this more comfortable for most folks.

This is one area the leading edge cuff might excel over the VGs if the cuff makes the wing create more lift at slower speeds. If you want to get off the ground quicker either get to flying speed faster with more power or lower the flying speed with a different airfoil.

[futr_alaskaflyer]

FWIW I have VGs inhereted from the previous owner. I have a different engine with different performance than all of you but what appears to be the difference is more control authority at a high AOA, slightly lower stall speed. I can fly around using ailerons indicating 0-10 mph. Does this have any real-world applicability in a plane that takes half again or more room to takeoff than land? Maybe with a broken cylinder, or during short landing contests. Maybe landing in the squirrely gusts swirling across my home strip.

I lose them mostly with pulling the wing covers off.

[flyguy]

VEEE GEEEs STOLE STUFF ON 170S - - BLAH BLAH DOANT KORNFUSE SHORT FEEL WITH REELY short FEEL

http://www.youtube.com/watch?v=8RQGSVf- ... re=channel

http://www.youtube.com/watch?v=dAx8BT6v ... re=related

http://www.youtube.com/watch?v=cWTcCtYl5Cs

THEN THIS REELY SHORT LANIN ROLL AN T/O

http://www.youtube.com/watch?v=sfeMLQNe ... re=related

NUTTIN BUT PONIES AN RAGS

[Showboatsix]

Short but expensive take offs & landings, and G is worried about the cost of the STOL or VG kits!

http://www.youtube.com/watch?v=YuE2cW8N ... re=related

[Bruce Fenstermacher]

There is no doubt as short landing and takeoffs go a 170 has a long way to go regardless of the modifications. Lots of those airplanes would have a heck of a time going over 100mph which is the other side of the coin.

[wingnut]

About 15 years ago, we ordered VG's for a Bonanza at customers request. He wanted to see if they worked as advertised without permanantly installing them (the 2 part adhesive system with kit normally pulls the paint up if you remove a VG). So we used carpet tape, which held great for several flights.
The before and after flights were performed during the course of 2 days, very similar weather conditions, time, temp, etc. The owner was disappointed. The VG's did improve stall speed, or maybe I should say stall characteristics/control authority, but not as much as was advertised. Also, he said 2-3 knots slower in cruise.
Now, I know this is a different airfoil, but the point of my post is this; you can order them, temporarily install, remove without paint damage, and send them back.

[GAHorn]

... you can order them... and send them back.

(sorry, couldn't resist)

[blueldr]

FWIW

General consensus of opinion among pilots that frequently fly the back country of Idaho who were queried at the
larger fly-ins at Johnson Creek:

Vortex Generators?

Work well on a Piper wing. Well worth the investment.

Do Squat or less for a Cessna Wing. Save your money.

[MontanaBird]

I am as usual, overwhelmed with the knowledge and support available from our 170org. Amazing. All are of course very welcome to stop in and take a coffee break here in Stevensville (Montana) and continue the conversation !

I will (with his permission) post a reply from the director of Micro Aero, when I asked him if VG's installed with an existing STOL kit are STC'd. They apparently are.

As follows:

Hello Michael:

Micro VGs and Sportsman’s STOL provide the very best improvement in performance and controllability for the C170B. We install VGs on many Sportsman’s equipped aircraft. (If you and I were running Cessna Aircraft Company today we would put the C170B back into production and they would have Sportsman’s and Micro VGs!) Micro VGs are mounted full span on the wings and full span bottom of horizontal stabilizer. The most important improvement with VGs in “improved controllability at slow speed.” Attached is more information on Micro VGs.

The Micro VG Kit includes an illustrated installation manual, VGs, STC, tools, templates, spares, Loctite Depend adhesive, ----- everything you need for the installation except a bottle of isopropyl alcohol, a roll of paper towels, pen to sign of the paperwork and a ladder to climb up and mount the VGs on the wings. Installation take a day.

With your order we need N-number, Serial Number, Shipping Address and any credit card. The Kit is $1450. If you want us to paint the VGs to match your airplane we need the name and number of the paint. But painting instructions are in the kit and any local body shop can match your paint.

We look forward to being of service.

Email #2 from Charles:

When I flew the C170B with Micro VGs for the first time I was surprised big time. I had not flown a C170B for 30 years and I laughed out loud all the way out of the traffic pattern. To takeoff in a “tail dragger” there are 5 thing you have to do:
1. Lift the tail up
2. Directional Control
3. More Directional Control
4. Still more Directional Control
5. Lift off

We eliminated 2-3-4, the tail went up and we were airborne. The C170B loves Micro VGs. (That was without the Sportsman’s and with it the airplane flies even better. Great combination.

When we developed the STC for Micro VG on the C182 we could not use my 1965 C182H because it has a Robertson R/STOL. (I wish it was a Sportsman's instead.) That was because if I used it I would only Be FAA STC approved for a 182 with Robertson so I used a stock C182Q for the FAA STC certification. I was shocked to find that the C182Q “stalled one knot slower than my Robertson 182!” I was blown away. It shows how important VGs are for your airplane.

The most important improvement with VGs is “IMPROVED CONTROLLABILITY AT SLOW SPEED!” W recently received phone call number #65 saying, “Thanks to your Micro Vortex Generators for saving my life and the lives of my passengers.” It always relates to “improved controllability at slow speed in some way or another. Several were Vmc situations in twins, two were split-flap in Cessna 340 and three were fuel exhaustion where they were going slow enough to make a survivable off-airport landing.

[HA]

I cannot vouch for any performance differences with VG's on a 170, but for instance they are definately worth it on our C340's. I put the first set we did on an airplane, did before and after flight tests (stalls, vmc, etc) and they performance with the VG's did EXACTLY what they said it would do. Lower vmc, stall speeds, and what we really use them for (and virtually ALL C340 owners get them for this) - a 300 lb gross wt increase for takeoff because they make that little 340 vertical fin and rudder act like a big 402 vertical which makes it certifiable for lower vmc, that was the limiting factor for the takeoff gross when originally certified.

Micro Aero has always been good to us, we buy quite a few spare VG's (and they've given us new mounting templates for free for when we do a repaint) as they can be knocked off by hail which is a job hazard for us. But any kit works the same near as I can tell, I think we have 3 different brands among our fleet. They don't pick up ice (I've only had it happen one time in a really serious icing encounter and that was runback) and they do knock a couple knots off your top cruise speed. the key is that they energize the boundary layer over the control surfaces, that's the magic.

[Bruce Fenstermacher]

I never noticed a reduction in speed with the VGs on my 170 from before and after. But to be honest I only installed the precision flight test instruments for some color speed tests I was performing which was after the VG flight tests. It would have been hard to tell a mile per hour difference with my regularly installed pitot/gage system.

[CF-HEW]

They don't pick up ice (I've only had it happen one time in a really serious icing encounter and that was runback)

Not pertinent for the 170, but they do pick up ice. Trust me, Moderate mixed will make a nice cone in front of each VG which will look like a spoiler on top of your wing in no time. Scared the crap out of me once on a Chieftain which is usually a truck in ice without the VGs. I wouldn't fly anything with VGs in anything more than light rime. ...but I agree that they don't pick up that classic trace of rime ice in cloud.

[futr_alaskaflyer]

To takeoff in a “tail dragger” there are 5 thing you have to do:
1. Lift the tail up
2. Directional Control
3. More Directional Control
4. Still more Directional Control
5. Lift off

We eliminated 2-3-4, the tail went up and we were airborne.

Well this time of year I eliminate 1 too

Only 5 is mandatory.