Wing Turbulators

[Thomas Smeltzer]

Can anyone tell me where to get clear wing turbulators?

Thanks,
Tom

[Larry Wong]

Can anyone tell me where to get clear wing turbulators?

Thanks,
Tom

You can try Wings and Wheels for turbulators, or for Vortex genarators from Park flyers hope that helps 

[Howard Rush]

What do you want them to do?

[Curare]

What do you want them to do?

Turbulate, clearly!

[Gordon Van Tighem]

Turbulate, clearly!

I believe you just put down an offer of information from a real turbulator expert.
If advised how they are expected to be used and plane type I am certain he would have been very helpful.
G

[Curare]

I believe you just put down an offer of information from a real turbulator expert.
If advised how they are expected to be used and plane type I am certain he would have been very helpful.
G

I am also certain that Howard would see it as a light hearted quip and not the put-down you see in it. I'm happy to let Howard decide, rather than speak for him as you are wont to do.

[Joe Yau]

Can anyone tell me where to get clear wing turbulators?

Thanks,
Tom

 I usually just make them with a Rotary cutter with a wafer blade, and clear Gorilla tape.

Edited in:
The Gorilla clear tape has thickness of .18 mm or 180 microns   

[Lauri Malila]

Thomas,

The best material for transparent turbulators is Oraguard stone guard film.
It's transparent polyurethane film for protecting paintjob against small stones, in cars or bicycles for example.
It's available at least in 130, 150 and 200 micron thicknesses, and can of course be stacked to make thicker turbulators.
It's very easy to cut with a cnc cutter and does not seem to care of water or UV exposure.

L

[Howard Rush]

Sorry, my question was a bit brief.  If you literally meant turbulators—doodads to force the transition from laminar to turbulent flow—guys above answered your question. Some folks refer to other doodads as “turbulators”. The vortex generators some of us have been putting on wings are intended to do something different, but for all I know they may be forcing transition also. I’m no expert.

I’m interested in trying the stuff Lauri mentioned. Uncle Jimby found a source for repositionable stuff like, I presume, the scratch-prevention film that comes on new phone displays. Some of us with unfashionably blunt stabilizer leading edges have festooned them with vinyl lattice stickers made by Mike Haverly.  They seem to work, and they look cool.

[Lauri Malila]

Howard,

The polyurethane film is quite expensive in bigger rolls but there seems to be smaller pieces available for bicycle nerds in Amazon.
This is maybe a little disturbing news for you who like shiny models, but the ultimate turbulator (and transparent!)
Is the sprayed-on granulate clear coat.
I don't know what you want to achieve with turbulators in stunt but in my gliders, compared to a string or tape turbulator, the spray is much better in all aspects; Launch height, sink ratio, stall recovery and how model handles rough air.  But it of course depends on used airfoils, classic ones still need the wire. And sprayed models are quieter, too. L

[Alan Resinger]

Howard ,  I just breceived some of the vinyl Uncle Jimby was using.  Will put a piece od it in mail to you.  Talked to Paul today and he wants some also. I might just cut a bunch and send you some precut pieces.  Which do you prefer?

[Larry Wong]

Howard ,  I just breceived some of the vinyl Uncle Jimby was using.  Will put a piece od it in mail to you.  Talked to Paul today and he wants some also. I might just cut a bunch and send you some precut pieces.  Which do you prefer?

I would think placement might be the next question

[Curare]

Howard,

The polyurethane film is quite expensive in bigger rolls but there seems to be smaller pieces available for bicycle nerds in Amazon.
This is maybe a little disturbing news for you who like shiny models, but the ultimate turbulator (and transparent!)
Is the sprayed-on granulate clear coat.
I don't know what you want to achieve with turbulators in stunt but in my gliders, compared to a string or tape turbulator, the spray is much better in all aspects; Launch height, sink ratio, stall recovery and how model handles rough air.  But it of course depends on used airfoils, classic ones still need the wire. And sprayed models are quieter, too. L

Lauri, I'm curious about this granular coat for my DLG models, is it removable?

[Lauri Malila]

Not really revovable, unless you sand it.
You mix 3 grams of mesh #600 milled glass (some use microballoons) to 20 grams of 2-pack auto clear. Then dilute about 100%.
Spray with 1,4mm nozzle from about 80cm away, (wings flat on table) just 1 or 2 passes. That will add less than a gramm to F1A size wings. (Top side only)
Of course, for test purposes you might use something water based. L

[Howard Rush]

Howard ,  I just breceived some of the vinyl Uncle Jimby was using.  Will put a piece od it in mail to you.  Talked to Paul today and he wants some also. I might just cut a bunch and send you some precut pieces.  Which do you prefer?

Either.  Thanks.

[M Spencer]

So your saying , for the last 50 years , all this cutting & polishing for APPEARANCE has been all been going backwards ,

as far as atmosphereic interface , and lift , and things like that .

   

[Dave_Trible]

Many times even going back to the countless 1/2 A's I built as a kid and through many other airplanes I've often thought the quickly finished, under finished , wood grain showing, rather poorly finished airplanes almost always flew the best-better than the highly slick and well finished airplanes did.  I would chalk that up to maybe they weighed a little less or just dumb luck but could be that rough texture ................Maybe we should re-sand those finishes more course and dull!  Every wonder about those divots on golf balls?  There is a science to that.

Dave

[Lauri Malila]

Just don't clean them mosquitos off the l.e. Now how to make the stick elsewhere, too?

[Serge_Krauss]

We found that polished ports in 2-cycle kart racing engines often performed less well than the rough sand-cast ones. Turbulent flow into the cylinder seemed to be the key. I fly an old Sky Ray (.35) that has a rounded stabilizer leading edge. Pitching seemed to improve with a sewing-thread turbulator rubber-cemented along the leading edge (although that was one of two simultaneous changes). This seems consonant with suggestions of using sharpened leading edges on thin sections that require the air to change directions with a tight radius there. Our HLG's flew slower with turbulated wings too. Apparently those roughened finishes do help the air-flow to bend along wing surfaces.

[Larry Wong]

We found that polished ports in 2-cycle kart racing engines often performed less well than the rough sand-cast ones. Turbulent flow into the cylinder seemed to be the key. I fly an old Sky Ray (.35) that has a rounded stabilizer leading edge. Pitching seemed to improve with a sewing-thread turbulator rubber-cemented along the leading edge (although that was one of two simultaneous changes). This seems consonant with suggestions of using sharpened leading edges on thin sections that require the air to change directions with a tight radius there. Our HLG's flew slower with turbulated wings too. Apparently those roughened finishes do help the air-flow to bend along wing surfaces.

. Okay I will ask the next question?  Location of them
? High point
Of wing, leading edge, hindge line? Trailing edge??

[Larry Wong]

Okay I will ask the next question?  Location of them
? High point
Of wing, leading edge, hindge line? Trailing edge??

[Lauri Malila]

It depends on airfoil, stab airfoil, tail moment, c.g,.. It can vary between 7% to 70% of wing chord.
But I have helped my friends in  this matter with F1C, DLG and f3J models,  and in general a good way to start experiments is to plant a 0,3mm turbulator at 60%, both wing and stab. It rarely does harm with low undercamber profiles with some cheek under l.e. L

[Howard Rush]

Lauri’s application is probably drag reduction.  We don’t care much about drag for stunt. Stunt boundary layer manipulation doodads can make the lift-vs.-angle-of-attack curve more predictable or reversible or increase max lift. What you want them to do determines what to use and where to put them. (Ideally, that is. I just do what PJ says, then extrapolate by guess.)

[Lauri Malila]

Not really drag reduction, as the wings have more drag with than without turbulation. Not sure about the spray, though.
I think it's more about making the model flyable, by stabilizing the boundary layer. At least the rather-rear -mounted wire turbulators in modern airfoils seem to help to keep the center of lift, or at least some kind of a vacuum bubble, better in its place. But it's clear that these rear (50..70%) mounted turbulators cause less drag than the classic 5..9%. But it's difficult to make comparisons between efects on classic and modern airfoils because the major difference in drag comes from underside of wing.
I apologize for the wrong terms, my experience is more on the practical side. L

[Dave_Trible]

I’ve found VG’s pretty effective in extending lift at lower speeds and higher AOA placed in the area shown- about 9-10 %.  Not so conclusive for the zig zag trip tape.  That works pretty well on the stab though- just behind the leading edge.  Here I believe it’s getting the flow consistently turbulent under all circumstances.

Dave

[Steve Helmick]

Make a glider. Any glider. Adjust it to glide straight. Add a turbulator to one side of the wing, without any other adjustments. Do the same with VG's. Report back.  Steve

[Lauri Malila]

Not that simple as it's an interaction of drag and lift.
A recording altimeter and a good pair of binoculars are a better aproach. L

[Serge_Krauss]

I can't set the positions exactly in each application I had. For the thin stab with the rounded leading edge, it was at the leading edge, because I wanted the air to stay attached as it changed direction or re-attach shortly, and that was a sudden change at the leading edge. The glider wings had the turbulation near the "high point." My friend's had a wing like Whittman's "Sweepette," where the high point was a spanwise ridge. Mine were very slick airfoils with testor's sanding sealer steel wooled to a shiny finish. They glided fast and long, but wouldn't transition. I stretched a thread span-wise at approximately at 20% chord and then across the high point area, gluing it down, and the model glided noticeably slower in both cases, but was more affected by gusts. That was 57 years ago; so I don't remember more. We weren't aeronautical engineers and just tried things out.

I found another interesting thing as I re-read "Gossamer Odyssey" this afternoon, although it doesn't mention position. In the text pictured below, the author is describing the MPA (Man Powered at very low Reynolds Number) tests of the "Puffin" and SUMPAC" groups in England.

What I'm getting from this forum discussion is that one can turbulate the key areas to keep the boundary layer attached, or he might be able  to turbulate the whole wing with OK results. What say?

[PJ Rowland]

Yeah I tested the zigzag tape..

Not only using the scissors, but had them cut through a cutter to vary their width.

The problem with zigzag tape is... its pretty ineffective when compared to VGs. The main issue is the physical height. Theyre isnt enough to assist our wings.

Lauri is an expert in gliders, and im sure tape works far better in glider applications for aiding lift. I personally dont beleive the VGs for gliders would help..  the aspect ratio, airfoil and airspeed is totally different.

What we use them for is completely different.
Igor uses the zigzag tape and swears by it.. he is a world champion and is easily one of the best minds looking at our sport.

But.... that still doesnt alter the facts that we want much more aggressive flow management.
Im not going to argue the point.. what I will say is Ive tested ALOT of different systems, and Tape/trip wire, sandpaper of the leading edge...aggressive wing scalloping, preleading edge flow distruption.. and obviously VGs..

By far the VG system demonstrates superior flow control and improvment.  Thats the beauty of a simple solution, it seems to be an elegant solution. 
We are only just NOW seeing really crude versions of VGs on 3D models.. the vg tech we use really isnt seen in aviation to do what WE use it for. Yeah yeah they are on lots of fullsize, but you will find they are lots in a row 20+
We get full aero benifit from just a single pair.. doesnt matter if its electric, piped, or designed in the 50s or the 2000 you get improvment.

All the work as to the hows, whys and wheres, has been done.. just put them where I say and spend the rest of your time practicing!!!

Note.. The clear VGs are avaliable from the Canadian stunt consortium.

[Curare]

PJ, have you messed around with height of the VG's? Or were you just using ones available to you?

G

Yeah I tested the zigzag tape..

Not only using the scissors, but had them cut through a cutter to vary their width.

The problem with zigzag tape is... its pretty ineffective when compared to VGs. The main issue is the physical height. Theyre isnt enough to assist our wings.

Lauri is an expert in gliders, and im sure tape works far better in glider applications for aiding lift. I personally dont beleive the VGs for gliders would help..  the aspect ratio, airfoil and airspeed is totally different.

What we use them for is completely different.
Igor uses the zigzag tape and swears by it.. he is a world champion and is easily one of the best minds looking at our sport.

But.... that still doesnt alter the facts that we want much more aggressive flow management.
Im not going to argue the point.. what I will say is Ive tested ALOT of different systems, and Tape/trip wire, sandpaper of the leading edge...aggressive wing scalloping, preleading edge flow distruption.. and obviously VGs..

By far the VG system demonstrates superior flow control and improvment.  Thats the beauty of a simple solution, it seems to be an elegant solution. 
We are only just NOW seeing really crude versions of VGs on 3D models.. the vg tech we use really isnt seen in aviation to do what WE use it for. Yeah yeah they are on lots of fullsize, but you will find they are lots in a row 20+
We get full aero benifit from just a single pair.. doesnt matter if its electric, piped, or designed in the 50s or the 2000 you get improvment.

All the work as to the hows, whys and wheres, has been done.. just put them where I say and spend the rest of your time practicing!!!

Note.. The clear VGs are avaliable from the Canadian stunt consortium.

[PJ Rowland]

Well...let me answer,

Yes I did play around with height, width, location, and physical VG shape. 

It would have been great to use something commerically available like the clear VGs. The problem I faced was back in 1995 when I first started to look into the airflow seperation problem noone had invented anything for stunt..

There were no VGs for stunt theory, it took the best part of 5 years development across 4 different aircraft and close to 2000 test flights before I settled on what I define as the "current setup" that was circa Year 2000. 
The VG technology didnt see world wide exposure until I competed in the 2004 World champs, subsequent trips to the US Nats also aided in the spread of the tech. Howard was the first to really use it heavily in the USA.
I wrote an article for Stuntnews and there is a reprint floating around on Stunthanger that explains the process of installation.


Lets consider the following ;

The first AUS nats the vgs were flown was 1995, so after 25 years of competition in Australia only 1 other pilot decided to use them successfully.
Yet in the USA, ive had World champions, Multi Nats winners, concourse winners, other Nats winners all use my technology to continue to improve and win using the latest tech.

That really shows who is serious about Stunt and who isnt.
The serious ones use it because they know if they dont they are giving up a serious advantage that their competitor will take advantage of.