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Another notch?

Why would VGs be less effective with split flaps? How would split flaps keep the airflow attached to the top of the wing? Did you ever put VGs on your Cessna? Great flaps, right? What did VGs bring to the party?
 
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A couple of guys have mentioned hitting their tails. High AOA while dragging it in with power? Change the relative AOA by making the final approach steeper. More flap angle-more drag-more capability to land it steep. VGs will help.
 
Stewart,
You are not understanding what the Vgs are doing. At high angles of attack, the airflow separates from the upper surface of any wing starting at the trailing edge moving forward towards the leading edge as the angle of attack increases. With the stock single slotted original flaps on the -18, they achieve their critical angle of attack at a certain angle of attack of the wing. Adding the Vgs at the leading edge influences the flow at the trailing edge in such a manner which allows the wing to achieve a higher angle of attack than without the Vgs and the flaps retaining their lift without stalling at a higher angle of attack.

The extra slot and the articulation of the PSTOL flaps helps in holding the airflow to the upper surface of the trailing edge at a higher angle of attack on the main wing. It does this by providing an incremental increase in angle of attack which is controlled by the surface immediately preceding the surface in question.

An optimum angle of change of a surface without stalling the surface and providing maximum lift is approximately 20 - 25 degrees. The angle between a stock -18's wing and it's flap is 50 degrees. The single slot is an improvement over a hinged flap without a slot and provides the same advantage as the slats on your wing does to the entire surface. The angle between an -18 wing and a PSTOL flap's first surface is aprox 25 degrees and the angle between the first flap segment and the second flap segment is another 25 degrees. This provides a total of 50 degrees of flap deflection with each surface only seeing a 25 degree change in airflow direction.

I did not and will not put Vgs on my 185 because with the wing extensions and drooping ailerons the stall speed is so low that I have run out of rudder on take off. If there were Vgs reducing the stall speed further, the rudder would run out of authority more often.
 
It's ironic that you challenge others to install and test when you haven't done so. VGs aren't about stall speed to me. They lower the speed at which I fly familiar attitudes at typical pattern speeds. And as for rudder? My Cessna rudder has VGs, too.
You should try them.

On the Cub? When I asked Jerry Burr where I should place VGs so they'd best compliment my slats? He told me I had it backwards. Slats energize the VGs. I'm always open to learning from guys who know. What I know? My wing works very well.
 
Pete, I wish I was closer so I could come by for and educational coffee once a week;-) I’m always impressed with the thought that goes into your posts.

Is the outside portion of the VG and Pstol equipped cub wing still benefiting from the energized airflow from the outer VGs at a high AOA?
 
It's ironic that you challenge others to install and test when you haven't done so. VGs aren't about stall speed to me. They lower the speed at which I fly familiar attitudes at typical pattern speeds. And as for rudder? My Cessna rudder has VGs, too.
You should try them.

On the Cub? When I asked Jerry Burr where I should place VGs so they'd best compliment my slats? He told me I had it backwards. Slats energize the VGs. I'm always open to learning from guys who know. What I know? My wing works very well.
Stewart, I expected that type of answer from you. You don't have anywhere the knowledge of aerodynamics that you think you have. And you appear to be too stubborn to learn. Years ago I earned my living experimenting in aviation aerodynamics. Sometimes I wish I never tried to help you.
 
Pete, I wish I was closer so I could come by for and educational coffee once a week;-) I’m always impressed with the thought that goes into your posts.

Is the outside portion of the VG and Pstol equipped cub wing still benefiting from the energized airflow from the outer VGs at a high AOA?
Thank you for your kind compliment Kevin.

Because I haven't tested that exact combination, this is just an educated guess. Yes.
 
Stewart, I expected that type of answer from you. You don't have anywhere the knowledge of aerodynamics that you think you have. And you appear to be too stubborn to learn. Years ago I earned my living experimenting in aviation aerodynamics. Sometimes I wish I never tried to help you.

I never said I have knowledge of anything other than what I've tried. One of my best friends is a professor of aerospace engineering so what I don't understand I bounce off of him. His take a year ago on Rev 3 flaps compared to Keller flaps has turned out to be spot on. I'll ask him about VGs with split flaps. Not to argue, but because I'm curious.

Bottom line? VGs work well on my planes. The Cessna was very familiar to me before VGs and the benefits of VGs were clear from the very first flight. My Cub is less familiar so I went with empirical knowledge from those who have similar airplanes. That's one of the benefits of group discussions.
 
.... I did not and will not put Vgs on my 185 because with the wing extensions and drooping ailerons the stall speed is so low that I have run out of rudder on take off. If there were Vgs reducing the stall speed further, the rudder would run out of authority more often.

This comment caught my eye.
My take is that the VG's are supposed to improve control authority,
and any reduction in stall speed is kind of a bonus.
From the MicroAero website https://microaero.com/

"[FONT=&quot]Micro Vortex Generators are small aluminum blades placed in a spanwise line aft of the leading edge of the wing and tail surfaces. They control airflow over the upper surface of the wing by creating vortices that energize the boundary layer. This results in improved performance and control authority at low airspeeds and high angles of attack."

[/FONT]
The VG kit for the 185 has VG's for the wing, the horizontal stabilizer, and the vertical stabilizer-
so ideally it should improve low speed control effectiveness in all three axises.

Cessna-180-185.jpg
 
Hotrod, here's my translation of Micro's ad. Get familiar with your stock wing's attitude at 70 mph. Add VGs. Duplicate the attitude and note the airspeed. You'll see about a 5mph reduction. Apply that to improved control response. If your controls were weak at 60 before they'll clearly be better at that speed after adding VGs because the airplane's attitude is flatter. Less AOA. I was reluctant for a few years before installing VGs on my Skywagon because I didn't care about stall speed and wasn't lacking control authority in most conditions. The difference they make is very easy to recognize in slow flight attitudes, which translates to slower landing speeds, which promotes shorter landings without any change to technique or familiar final approach attitude.
 
This comment caught my eye.
My take is that the VG's are supposed to improve control authority,
and any reduction in stall speed is kind of a bonus.
hotrod, What I did not mention is that condition presented itself during a high wind very rough water take off. In those conditions I use 40 degrees of flap to reduce the pounding impact loads on the entire airframe by transferring as much of the weight as possible to the wings sooner during acceleration. That works for me. Vgs on the vertical stab would not have helped in that situation as the tail was blanked by the flaps and not by the rudder stalling. As soon as the flaps were retracted, rudder authority returned.

Under light loads, I see indicated speeds of 37 knots lifting off the water. Light loads in my plane is still heavy. I also never see a need for extreme high angle of attack behind the power curve operations which is the condition where the Vgs shine.
 
Anybody running VGs with Sportsmans..... I have the Sportsmans with standard wings and debating VGs, I don't like the thought of wing covers and VGs.
 
I've thought about adding a Sportsman a few dozen times but never did. To the VG comment? As long as the wing covers have solid nylon in the VG area? No problem. If you're putting mesh covers on in a tailwind? You'll need to amend your technique. Me? If I use my mesh covers the solid covers go on first.
 
Anybody running VGs with Sportsmans..... I have the Sportsmans with standard wings and debating VGs, I don't like the thought of wing covers and VGs.
Good thread on that subject. https://www.supercub.org/forum/showthread.php?53721-Vgs-vs-sportsman
Thinking of doing the same. 1954 Pponked with high compression pistons, tuned exhaust and fuel injected. Light weight rocket ship but heavy in the nose with that three blade prop. Wondering if the Micro VG's would give me a little better response in the rudder and elevators????
 
Good thread on that subject. https://www.supercub.org/forum/showthread.php?53721-Vgs-vs-sportsman
Thinking of doing the same. 1954 Pponked with high compression pistons, tuned exhaust and fuel injected. Light weight rocket ship but heavy in the nose with that three blade prop. Wondering if the Micro VG's would give me a little better response in the rudder and elevators????
Put some ballast in the tail. It will do a lot better when the CG is correct without any modifications.
 
"Nose heavy" is subjective. Is it within the CG envelope? Is so? Yes, VGs will improve it. Finding the plane and pilot's optimal operating CG first will make the VG improvement more pronounced. Once I'm out of trim and keeping nose up with elevator any VG benefit is difficult to judge.
 
I installed Micro VG's on my old C150/150TD,
but to tell the truth I couldn't feel much difference in how it flew.
But I fly my 180 differently than I did the 150--
I carry some power for almost all landings.
And have gotten more familiar with slow, steep, nose-high, behind-the-power-curve approaches.
So I've been thinking about putting VG's on the 180.

I've thought off and on about installing a sportsman cuff,
but by the time you install & paint that's a lot more money.
Plus I don't like the way the wingtips & wing root fairings look--
IMHO a stock wing root & stock tip looks so much better.
 
Fly a Sportsman and decide. For prolonged slow flight and turns the benefit is remarkable. Better aileron control - better glide ratio - more solid at low airspeed. No experience with VG's on a Cessna tho.

Gary
 
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