Vortex generators explained

Had them on my Cherokee. Lowered the stall speed a good ten knots, complete control at slow speeds, and I had a heck of a time actually stalling it. The thing mostly mushed. Were I doing any kind of backcountry flying they'd be the first thing I bought for the aircraft.
 
At about 5:52 in the video you can see how much of a beating the horizontal stabilizer takes presumably from all the crap that kicks up going in and out of all those unimproved back country locations. Yikes!
 
I sure would love to do some bush flying like that!

I did my senior research paper (BSME) on those micro vortex generators...back right about the time that company started selling them I believe....so that brought back some memories for me...thanks for sharing
 
VGs made my airplane an entirely different beast... it feels like i have full aileron control darn near to taxi speed! They are a great investment!

inreally had to readjust my landings once I got them, with a tailwheel plane, i kept touching down tailwheel first right after getting them and not being patient enough to let her settle right on the runway just due to visual clues telling me we should be on the ground right now.
 
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Dumb question, why don’t all planes have them, at least all new planes? Seems like it would be as fundamental as having flaps on a plane, or differential deployment of ailerons.
Is there any downside to them?
 
LongRoadBob said:
Dumb question, why don’t all planes have them, at least all new planes? Seems like it would be as fundamental as having flaps on a plane, or differential deployment of ailerons.
Is there any downside to them?
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Lots of GA planes don’t need them for their mission, and they add complexity and expense. There can be (not always, depends on the details) a slight reduction in top speed as well.

And, BTW, I wouldn’t call flaps fundamental. I’ve flown a number of aircraft (Citabria, Decathlon, Great Lakes, J-3 Cub, Champ) which do just fine without flaps.
 
LongRoadBob said:
Dumb question, why don’t all planes have them, at least all new planes? Seems like it would be as fundamental as having flaps on a plane, or differential deployment of ailerons.
Is there any downside to them?
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They create drag, so if you want speed....you don’t want VGs.

They only help when approaching stall speeds...the only time I do this is when I’m flaring to land

Edit: supposedly they are also used to fix design problems with supersonic aircraft, not sure if that’s true or not. If you search, you’ll see white papers by NASA about them.
 
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LongRoadBob said:
Dumb question, why don’t all planes have them, at least all new planes? Seems like it would be as fundamental as having flaps on a plane, or differential deployment of ailerons.
Is there any downside to them?
Click to expand...
I would love to try them on my plane, but... I don't want to go through the expense of install + it sure would be a PITA being parked outside in the winter with wing covers..
 
What manufacturer AOA is that? Garmin AOA adds more lines to the top of the display: green, yellow, then red as one gets closer to stall. This works opposite.
 
MooneyDriver78 said:
They create drag, so if you want speed....you don’t want VGs.

They only help when approaching stall speeds...the only time I do this is when I’m flaring to land

Edit: supposedly they are also used to fix design problems with supersonic aircraft, not sure if that’s true or not. If you search, you’ll see white papers by NASA about them.
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i seen zero speed loss, granted im a 105mph cruiser give or take for a 73 year old airspeed indicator... ive heard some ppl say a few mph... wasnt my experience but could vary model to model..
 
Huckster79 said:
i seen zero speed loss, granted im a 105mph cruiser give or take for a 73 year old airspeed indicator... ive heard some ppl say a few mph... wasnt my experience but could vary model to model..
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You can’t disturb the airflow to create vortexes and not add some drag, in other words you can’t break the laws of physics. But the difference at slow speeds can be minimal, especially if you clean the wing, then install the VGs, because cleaning the wings just removed some drag. I cringe when I see them on modern faster aircraft, it would be like putting snow tires on a Ferrari.
 
MooneyDriver78 said:
... I cringe when I see them on modern faster aircraft, it would be like putting snow tires on a Ferrari.
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Boy, howdy... I hate that, too!
bb439a7c76968bc71b13045420faddb0.jpg
 
My curiosity is piqued...I wonder what effect it might have on the Grumman trainers and their stall characteristics(?)

edit: I want to try this...advice on getting approval? I don’t think there is a current stc. Willing to bet the RV VG kit would be just right
 
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My Cherokee was pretty fast for the breed, so I don't think the VG's slowed it down any. Were my mission to land in mud holes and gravel banks and the like, they'd be high on my list. Thankfully that isn't my mission, so I'll pend my coin on something else.
 
MooneyDriver78 said:
You can’t disturb the airflow to create vortexes and not add some drag, in other words you can’t break the laws of physics. But the difference at slow speeds can be minimal, especially if you clean the wing, then install the VGs, because cleaning the wings just removed some drag. I cringe when I see them on modern faster aircraft, it would be like putting snow tires on a Ferrari.
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I documented TAS for several different conditions before I dropped the plane off. It’ll be interesting to see what the differences are when I get her back.
1CFC7498-E8CF-418A-BF07-2264442C5DCF.jpeg
 
I debated adding the to help get some roll back with flaps down on my Robertson STOL, maybe one day but I’d be concerned with breaking/loosing the VGs
 
James331 said:
I debated adding the to help get some roll back with flaps down on my Robertson STOL, maybe one day but I’d be concerned with breaking/loosing the VGs
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I haven't had any break but I did knock one off while cleaning the plane. No problem, I just glued it back on. I did make sure to use an adhesive that was aluminum friendly...:goofy:
 
steingar said:
Had them on my Cherokee. Lowered the stall speed a good ten knots, complete control at slow speeds, and I had a heck of a time actually stalling it. The thing mostly mushed. Were I doing any kind of backcountry flying they'd be the first thing I bought for the aircraft.
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Lowered indicated stall speed ten knots. When you get going very slowly, ASIs tend to go wonky.
 
MooneyDriver78 said:
If you have hangar rash on the leading edges, it really hurts the aerodynamics. I removed an extraneous bracket from my wing mounted taxi/landing lights, and I improved my speed by 2%.
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I’ve been wanting to ditch my tail mounted beacon for that as well as cosmetic reasons
 
Twin_Flyer said:
Finally, a paint progress report...:yikes: You're killing us...:nono: You going to make us wait for the grand unveiling...:yes:
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No more waiting than I’m doing. I’ll post the pics as soon as she’s done! :)
It’s like being a kid before Christmas but the clock stopped at 11pm on the 24th.
 
MooneyDriver78 said:
The paint job should improve your speed, possibly a lot depending on condition of the wing surfaces beforehand.
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Yeah, unfortunately there’s no true comparison with both the changes at the same time. My paint was pretty bad before in spots.
 
looking forward to your videos Kevin!

MooneyDriver78 said:
You can’t disturb the airflow to create vortexes and not add some drag, in other words you can’t break the laws of physics. But the difference at slow speeds can be minimal, especially if you clean the wing, then install the VGs, because cleaning the wings just removed some drag. I cringe when I see them on modern faster aircraft, it would be like putting snow tires on a Ferrari.
Click to expand...

I think the idea is in the placement of the VG. Depending on where they are placed the result might be negligible at low angle of attacks / high speeds...like maybe the air isn't hitting them in such a way to create any meaningful vortex or drag...while at lower speeds the relative wind hits them differently creating the vortex, which increases the boundary layer energy, etc...
I'd speculate that it varies between different aircraft types and configurations
 
Brad W said:
looking forward to your videos Kevin!



I think the idea is in the placement of the VG. Depending on where they are placed the result might be negligible at low angle of attacks / high speeds...like maybe the air isn't hitting them in such a way to create any meaningful vortex or drag...while at lower speeds the relative wind hits them differently creating the vortex, which increases the boundary layer energy, etc...
I'd speculate that it varies between different aircraft types and configurations
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You should be a VG salesman. :)
 
MooneyDriver78 said:
You can’t disturb the airflow to create vortexes and not add some drag, in other words you can’t break the laws of physics. But the difference at slow speeds can be minimal, especially if you clean the wing, then install the VGs, because cleaning the wings just removed some drag. I cringe when I see them on modern faster aircraft, it would be like putting snow tires on a Ferrari.
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i concur... just on my slow old gal it was negligible...
 
LongRoadBob said:
Dumb question, why don’t all planes have them, at least all new planes? Seems like it would be as fundamental as having flaps on a plane, or differential deployment of ailerons.
Is there any downside to them?
Click to expand...

Loss of speed. Sometimes a fair bit.

GrummanBear said:
My curiosity is piqued...I wonder what effect it might have on the Grumman trainers and their stall characteristics(?)

edit: I want to try this...advice on getting approval? I don’t think there is a current stc. Willing to bet the RV VG kit would be just right
Click to expand...

There's really zero reason to put VGs on a Grumman. Just be gentle on the rudders and the stall characteristics are not bad at all. Don't wreck that wing.
 
N1120A said:
Loss of speed. Sometimes a fair bit.



There's really zero reason to put VGs on a Grumman. Just be gentle on the rudders and the stall characteristics are not bad at all. Don't wreck that wing.
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I think experimentation is one of the things that makes life most fun to me....but if there was someone who already tried it and got bad results, I would turn my interest elsewhere. ...Besides, I have two.
 
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