Vortex Generators? looking for real world feedback

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Andy Young
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Re: Vortex Generators? looking for real world feedback

Post by Andy Young »

Mog wrote:
Wed Feb 03, 2021 8:33 pm
To be clear, I land tail low and then end up tail high on roll out. I do not consider this a wheel landing as it’s done at much slower speeds than is possible in a true wheel landing. My raised tail is typically due to heavy braking more than elevator.
Sounds like you’re describing exactly the kind of landing scenario that both VGs and gap seals drastically improve.

Your landing technique sounds very much like what I do when I’m trying to get in very short, though it wasn’t clear to me if you’re actually touching the tailwheel initially or not. I do what I call a tail-low wheel landing, in which the tailwheel never quite touches the ground, the mains touch, then the airplane comes up about to a level attitude, modulated by braking, with the yoke full aft. The tailwheel finally touches when the plane is almost stopped.

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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

Guess the tailwheel touches on my landings based on how short the strip is. It’s all just natural I suppose.

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mauledrvr
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Re: Vortex Generators? looking for real world feedback

Post by mauledrvr »

Stirring the pot again,
Flew my 1985 M5-180 for fifteen years without Vortex generators, sold the plane and flew the exact sister ship 1985 M5-180 WITH Vortex generators for the next five years. Thought I was just a club fisted flyer with no feel, as I couldn't tell the difference in the two as far as slow speed handling. Well like a boomerang the first M5 is recently back, still without VG's.
After being a sceptic all these years (read idiot) I'll be ordering these aluminum gadgets as they really do improve that very short window between control and the backside of minimum controllable airspeed. Under what would be normal conditions, 10kts on the nose, 55 over the fence, flared and nothing but mushy controls, felt like you're just along for the ride. It was such a distinct difference I thought there was a control surface problem, even did a very quick peek to see if the flaps were both down all the way. Dishearteningly odd sensation.
The tailfeathers are coming off this winter for fabric/paint and we'll install the full set then. So add one more to VG believer list.
Go Easy

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andy
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Re: Vortex Generators? looking for real world feedback

Post by andy »

My MX-7-180 handles much better landing with vortex generators than without. I had them installed in 2010 by Maule Flight when they rebuilt my airplane. Before the vortex generators, the airplane would suddenly stop flying and plop onto the surface. With the vortex generators it continues to have lift and control all the way to touchdown as well as a lower stall speed. There doesn't seem to be any speed penalty in cruise but my 31" bush wheels create so much drag that I wouldn't notice.

According to Micro Aerodynamics' website the reason that the airplane handles so much better at low airspeeds is that when a stall starts at the wing root and tries to move toward the wing tip, the vortices inhibit it's progression so I have lift longer. With full flaps they say that the vortex generators lower stall speed about 4% to 43 mph but I've found that they actually lower it more than that. I did stalls in all flap settings at altitude when I was in McCall ID. With 48 degrees it stalled around 35 mph but the airspeed indicator isn't accurate at that low an airspeed.

I'm much more comfortable landing at a lower final approach airspeed (55 mph) with the vortex generators so that opens up shorter airstrips. Now I have to worry about landing and not being able to take off again with the 180 hp engine so I use a takeoff and landing distance estimate of 500 feet unless the landing zone is uphill.
Andy
1986 MX7-180
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Re: Vortex Generators? looking for real world feedback

Post by G21pilot »

I installed them on my 4-210 and the low speed handling is incredible. I regularly approach at 50 indicated in gusty wind knowing that I’ll have full aileron control. I climb at 40 indicated and flaps 20 to clear obstacles and the plane is rock solid.

My airplane also has a Pitts elevator gaps seal.

Power on stalls are at an insane deck angle and the stall recover is gust to briefly relax back pressure.

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