Vortex Generators? looking for real world feedback

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Rezrider
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Vortex Generators? looking for real world feedback

Post by Rezrider »

So I've searched the posts about VG's but I'm looking for real world feedback from those that have installed them and notice a difference from before to after.
Seems like they might help the short wing M-5, but still a lot of money for some aluminum chips.
The annual is coming up so now's the time to do it!
Thanks all.
1980 M5-235
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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

Makes a significant difference. Maybe not as much if you use long runways and come over the fence at 75mph. But if you use short runways and like to get slow then they help for sure. On mine it really changed the stall to nothing more than a mush.

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flyusn99
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Re: Vortex Generators? looking for real world feedback

Post by flyusn99 »

Rez,
On my M-5-235, I noticed about a 5-8mph reduction in stall speed while carrying power. At Idle almost no noticeable improvement, perhaps a mph or maybe two, Nothing to get excited about. That was on wheels. I noticed almost no difference while on floats, power or not. I think they are a good thing to have on but not the mind blowing improvement that some people have experienced. Not saying they are wrong, just didn't pan out that way for me. YMMV.

James

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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

My opinion is that they are not so much about reducing stall speed but rather make flight just above and into a stall much more controllable. It reduces or eliminates buffeting and gives you far more aileron control. My M4 prior to VG’s required rudder control below a certain speed because the ailerons were not as effective as they could be. But with the Vgs you have full aileron all the way through a stall.

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LCDRLES
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Re: Vortex Generators? looking for real world feedback

Post by LCDRLES »

I agree with MOG. On our M5-180, VG’s didn’t drop the stall speed as much as they improved the slow speed controllability.
Definite improvement on the M5 the slower you go and worth it to me. Downside is they are a pain in the a.. when fueling.
I would add them again to an M5 Maule, for sure.
C180 Cessna, no, they seem to add nothing in my opinion to the Cessna wing.
But, they really improved the Piper Pacer/160 I flew, also, in the same regime as the Maule.
1984 M5 180C, N5654B
1956 Cessna 180, N4971A
1977 7GCAA, N1165E

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andy
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Re: Vortex Generators? looking for real world feedback

Post by andy »

I noticed a significant improvement in low speed stall control on landing. Before VGs the airplane would suddenly stop flying during the flare as the airspeed decayed. It was hard not to bounce on landing. I attributed that to rapid progression of a stall over the wing. I have the short wing, too.

After VGs the airplane was much easier to land gently and avoid a bounce. Doing stalls at altitude before VGs would produce a sudden break in one wing (usually the left) around 43 mph IAS with full flaps. After VGs the airplane just mushes in a stall below 40 mph with full flaps.

The biggest benefit is being able to land at a slower final approach airspeed with more confidence on short airstrips. MicroAerodynamics says that the VGs interfere with the progression of a stall from the wing root to the wing tip and I believe them. I think they are definitely worth the cost.
Andy
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Re: Vortex Generators? looking for real world feedback

Post by Rezrider »

All good info to consider, thanks guys. I guess the cons are washing and refueling but those can be dealt with.
I like the idea of airleron effectiveness at slow speeds. I think the reduced stall speed would be great but the lack of true angle of attack means the tail will touch first anyway so no real benefit there.
I fly the M-5 at higher elevation short-ish dirt strips so thats where I look for improvements.
I think I'll order them.
Thanks again.
1980 M5-235
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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

Washing is tolerable, fueling has never been an issue for me. And I would say VG’s are even more important at the DA’s you fly at some times. Could severely reduce the base to final spin problem. I’ve been in an M7 that stalled twice on base to final. Was even in a turn. It was not an issue at all and recovery was uneventful at worst.

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Re: Vortex Generators? looking for real world feedback

Post by Curtis »

Don’t waste your money. Could tell absolutely no difference on a short wing M4. You would have to have access to a controlled environment such as a wind tunnel to say “Hey it made a difference of 2 miles an hour and it is more stable” They work on jets or planes with high speed wings. They put them on the horizontal stabilizer on high speed jets to help with Mach tuck. If you want to lower your stall speed and enhance you low speed performance install a stall fence on the top of the wing. Just my two cents worth but speaking from experience as a racing jet crew chief and believe me we have all the tricks in trying to get the speed along with stability so we know what works slow is not ideally for going fast and vice versa.
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HeavyLoad
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Re: Vortex Generators? looking for real world feedback

Post by HeavyLoad »

Have them on my M5. I asked the same questions before I installed them. And yes I do notice a difference at low low speeds. It's nicer to handle. She also seems to cuddle, hug, and smell better.
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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

Curtis wrote:
Fri Jan 29, 2021 4:15 pm
Don’t waste your money. Could tell absolutely no difference on a short wing M4. You would have to have access to a controlled environment such as a wind tunnel to say “Hey it made a difference of 2 miles an hour and it is more stable” They work on jets or planes with high speed wings. They put them on the horizontal stabilizer on high speed jets to help with Mach tuck. If you want to lower your stall speed and enhance you low speed performance install a stall fence on the top of the wing. Just my two cents worth but speaking from experience as a racing jet crew chief and believe me we have all the tricks in trying to get the speed along with stability so we know what works slow is not ideally for going fast and vice versa.
That’s interesting, I installed mine on my M4. The difference was notable. It’s one of the first mods I would do on a new to me Maule aside from gear legs and Bush wheels.

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maules.com
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Re: Vortex Generators? looking for real world feedback

Post by maules.com »

I worked with the manufacturer when they were going through FAA overseen testing.
Micro aerodynamics used an MX7-235 initially and I used an M7-235.
They sent me the kit and how and where to fit them.
After tests we shared results and came up with the same numbers.
Stall at all different flap settings are slower. The difference depends on airspeed, the slower you go the more effect.
Roll and elevator authority are greatly improved with the VGs especially with gap sealed tail feathers.
Jeremy
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Mog
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Re: Vortex Generators? looking for real world feedback

Post by Mog »

maules.com wrote:
Fri Jan 29, 2021 10:54 pm
Roll and elevator authority are greatly improved with the VGs especially with gap sealed tail feathers.
Gap seals on the M4, that’s what I need. Why in the world they didn’t initially approve them for the M4 is beyond me. And Cub crafters stopped selling pieces of the good stuff last I looked.

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Re: Vortex Generators? looking for real world feedback

Post by Rezrider »

HeavyLoad wrote:
Fri Jan 29, 2021 4:54 pm
Have them on my M5. I asked the same questions before I installed them. And yes I do notice a difference at low low speeds. It's nicer to handle. She also seems to cuddle, hug, and smell better.
That's pretty funny right there.
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Re: Vortex Generators? looking for real world feedback

Post by onfinal »

Hi Rezrider,
A couple of YouTube links on VGs. (I apologise if you have already seen them).
Both are as 'scientific' as you can get in a SEP without carrying an academic with 3 ton of measuring equipment in the backseat.
On a Supercub - USA-35B airfoil
https://www.youtube.com/watch?v=aXS0nF1ILns
On a Bearhawk - Ribblet airfoil
https://www.youtube.com/watch?v=7I_ac9Wek-k
Sorry, can't find one for Maules - modified USA-35B airfoil.

Interestingly both reviewers mention about also placing VGs on the elevator underside to maintain attachment of that airflow.
I find the main benefit is improved control authority at slow speed, both in level flight and banking.
I have VGs on the wings and underside of the horizontal stabilisers, along with the gap seals.

I can vouch they improve her smell as well.
M6-235

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