Home-Made VG's
- Thread starter wec502
- Start date
Dave Calkins
Registered User
Anchorage, Alaska
I have made my own.
I don't have any photos handy, so you'll have to bear my verbal description.
The most simple description is that they: .......look like large MicroVG's(a brand name), that are made as a set out of a singe piece of light aluminum sheet bent up on each end.
In the VG kits that have 'sets', or 'pairs' there are two VG's set in mirror image(not the "landshorter" VG's, which are not arranged in 'sets', which I do not understand).
My homemade jobs are a piece of .020" aluminum sheet that is 'bent up on each end at an angle' to form a "pair" or "set" of VG's. They are pop-riveted or double-sticky taped to the wing and then a fabric finishing tape layed over the set.
Yes they work, just like the very good Micro-Aerodynamics VG kits. Mine are experimental, and I don't do them anymore because it's cheaper and better in the long run to buy Micro-Aerodynamics VG's kit which is very complete, simple, quick, and removes all chances of error from the installation on a Cub airplane.
good luck and have fun. DAVE
I don't have any photos handy, so you'll have to bear my verbal description.
The most simple description is that they: .......look like large MicroVG's(a brand name), that are made as a set out of a singe piece of light aluminum sheet bent up on each end.
In the VG kits that have 'sets', or 'pairs' there are two VG's set in mirror image(not the "landshorter" VG's, which are not arranged in 'sets', which I do not understand).
My homemade jobs are a piece of .020" aluminum sheet that is 'bent up on each end at an angle' to form a "pair" or "set" of VG's. They are pop-riveted or double-sticky taped to the wing and then a fabric finishing tape layed over the set.
Yes they work, just like the very good Micro-Aerodynamics VG kits. Mine are experimental, and I don't do them anymore because it's cheaper and better in the long run to buy Micro-Aerodynamics VG's kit which is very complete, simple, quick, and removes all chances of error from the installation on a Cub airplane.
good luck and have fun. DAVE
Bugs66
MEMBER
Spokane WA
I have the Landshorter (Harrison) VG's on my Cub. They are Lexan and very tough. These VG's are not put in pairs but go along continously. They are also set back further. I appreciate this when I clean my leading edges from bugs. ~$200-ish for complete set for my wings and tail.
I am no STOL expert but I can get some pretty high alphas and have good control authority. They seem to be doing their job. Harrison designed the VG's for the Quest Kodiak so he knows his stuff.
I am no STOL expert but I can get some pretty high alphas and have good control authority. They seem to be doing their job. Harrison designed the VG's for the Quest Kodiak so he knows his stuff.
gdafoe
FRIEND
Castle Well Airpark SE of Wickenburg AZ
Actually there are several very interesting "lift enhancing" devices used on the Kodiak wing. They just got a 500 lb gross weight increase approved which added even more clever little devices. Sure wish I'd taken pictures of them when it was here in February. Maybe somebody has some pictures and can explain how it all works. But I digress and don't want to hijack the VG thread.
brown bear
Registered User
emporia ks
The lexan angles that you buy at the hardwear store for sheet rock corners work well and are eazy to trim to size and shape.
Doug
Doug
behindpropellers
Registered User
NE Ohio
Laz said:
Time to search and read....hours upon hours of reading.
Jerry Burr explains all of this.
Tim
snowyriver
Registered User
Alaska
Landshorter VG's
Not sure but LandShorter may be out of business. I tried repeatedly for weeks to get an answer to my phone messages asking for a set for my murphy rebel. Not even a callback.
Not sure but LandShorter may be out of business. I tried repeatedly for weeks to get an answer to my phone messages asking for a set for my murphy rebel. Not even a callback.
Laz, I agree. Not just the set back, but the size and shape as well. All they do is make the air swirl and bring the high speed free stream air down into the slowed boundary layer next to the skin. It's not rocket science...well, maybe it is... Anyway, if you have ever seen the pictures of them, that swirl goes a long way downstream. Think "wingtip vortices".
I did some looking in Hoerner. He gives the size, shape, and angle they should be but doesn't say much about placement. They use them for a lot of things, usually not for the stall like we want them for. So, other than there being some abstract perfect place for one to be, I don't think it matters that much where it is. One place may be best, but like Horse Shoes, it doesn't have to be perfect, it just needs to work. Otherwise there wouldn't be such variation.
Most of the VG's you see are shorter than Hoerner and NACA suggests, too. My guess is because we don't like them that big and we go buy the smaller, prettier ones. So, now the smaller ones are better.
That's what I think, but I'll keep looking.
I did some looking in Hoerner. He gives the size, shape, and angle they should be but doesn't say much about placement. They use them for a lot of things, usually not for the stall like we want them for. So, other than there being some abstract perfect place for one to be, I don't think it matters that much where it is. One place may be best, but like Horse Shoes, it doesn't have to be perfect, it just needs to work. Otherwise there wouldn't be such variation.
Most of the VG's you see are shorter than Hoerner and NACA suggests, too. My guess is because we don't like them that big and we go buy the smaller, prettier ones. So, now the smaller ones are better.
That's what I think, but I'll keep looking.
Tim
FRIEND
Petersburgh, NY
Laz, Jerry Burr has a graph on placement of VGs, what they do with where they are placed. There's not much difference. I though I saved the graph but I can't find it. I think it's in the photo gallery, but I can't find it there either.
I'm sure someone has it and will post it.
Tim
I'm sure someone has it and will post it.
Tim
NimpoCub
Registered User
Nimpo Lake, BC . . . AKA "the Floatplane Capital o
From what I read (from all the suppliers) they go about 8-10% of your chord behind the leading edge. So if your chord was 100", they'd go 8-10" behind your LE. Too far one way (don't 'member now) and they cost speed, too far the other way & they get inefficient.
Maybe someone who knows what they're talking about will chime in.
Maybe someone who knows what they're talking about will chime in.
courierguy
MEMBER
Inkom, Idaho
While Joa Harrison may be the largest vg maker (he's 6'6 or 8, no fat, a very large dude and a lot of fun) apparently he is not making them anymore? News to me. BUT,the stencils that Micro include sure make it quick and easy to install. If you are experimental the cost isn't bad if your time is worth anything.
Jerry Burr
MEMBER
Sedro Woolley, Washington.
Vg's
Hi Laz. I don't want to get into a drawn out on this topic, but the thing to look at on the graph is the fact that at 10% of chord there is no difference in the stall speed with V.G.'s and power and full flaps, and with no V.G.'s and power and full flaps. If you don't use power and flaps for takeoff or landing, then 10% will work fine for you. Jerry B.
Hi Laz. I don't want to get into a drawn out on this topic, but the thing to look at on the graph is the fact that at 10% of chord there is no difference in the stall speed with V.G.'s and power and full flaps, and with no V.G.'s and power and full flaps. If you don't use power and flaps for takeoff or landing, then 10% will work fine for you.
Jerry B.
Jerry Burr
MEMBER
Sedro Woolley, Washington.
V.G.'s
Leading edge to trailing edge. Jerry B.
Leading edge to trailing edge. Jerry B.
stevensonjr
Registered User
Lafayette La
Jerry, chord wise, where would you put VG'S on a no flap J3? 100 hp if that makes any difference. Bill
cubdriver2
FRIEND
upstate NY
stevensonjr said:
Good ? Bill, I'd also like to know
Glenn
Jerry Burr
MEMBER
Sedro Woolley, Washington.
Clean or flapless
Check the chart. Clean (flaps up) is the same as no flaps. All Cubs have the same airfoil. Jerry B.
Check the chart. Clean (flaps up) is the same as no flaps. All Cubs have the same airfoil. Jerry B.
stevensonjr
Registered User
Lafayette La
Jerry, I'm chart challenged, but am I seeing .38 % or about 4 tenths of an inch for a 100 inch chord? That would be on the leading edge for the slowest no flap stall speed? Am I reading it wrong? Bill
aileron control
I have a question.. Along with the graph above is there any information on how control surfaces are affected? For instance during a stall are the ailerons any more effective at the slower speeds ( I know they should be neutralized but)? Since the elevator effeciency is not changed does it "quit" or stall before the main wing? I would guess that to be a bad thing if so remember ing early flight training stating that the main wing stalls first so the elevator can still. Does rudder have enough authority to level wings during a power on stall or power off stall at the lower speeds? Thank you in advance.. Dave
I have a question.. Along with the graph above is there any information on how control surfaces are affected? For instance during a stall are the ailerons any more effective at the slower speeds ( I know they should be neutralized but)? Since the elevator effeciency is not changed does it "quit" or stall before the main wing? I would guess that to be a bad thing if so remember ing early flight training stating that the main wing stalls first so the elevator can still. Does rudder have enough authority to level wings during a power on stall or power off stall at the lower speeds? Thank you in advance.. Dave
Jerry Burr
MEMBER
Sedro Woolley, Washington.
stuff
For a flapless Cub 4% would work fine. 1.1% for flapped Cubs. .38% was just a test, the most forward point. not at all pratical. Aileron data was useful only to me as they were drooped. On the Micro tests, enough V.G.'s were used on the elevator to complete the wing tests. Then the elev. was reconfigured to be just effective enough to stall the wing. If you can do a medium power spin to the right, your rudder should be fine. If your right rudder pedal is against the firewall before the break, you could probably use some V.G.'s on the rudder. I suggest doing all the stall tests at gross wt. and using as much power as you usually land with. Jerry B.
For a flapless Cub 4% would work fine. 1.1% for flapped Cubs. .38% was just a test, the most forward point. not at all pratical. Aileron data was useful only to me as they were drooped. On the Micro tests, enough V.G.'s were used on the elevator to complete the wing tests. Then the elev. was reconfigured to be just effective enough to stall the wing. If you can do a medium power spin to the right, your rudder should be fine. If your right rudder pedal is against the firewall before the break, you could probably use some V.G.'s on the rudder. I suggest doing all the stall tests at gross wt. and using as much power as you usually land with. Jerry B.
brown bear
Registered User
emporia ks
Snowyriver wrote
" Not sure but LandShorter may be out of business. "
I checked with then today and they still sale VG's
Doug
" Not sure but LandShorter may be out of business. "
I checked with then today and they still sale VG's
Doug
snowyriver
Registered User
Alaska
That's good news. I have left at least 4 messages with them, the last one saying "I want to buy VG's for my plane .Please call". No response. I get their recording and leave a message. Craig
