Golf Balls travel further because of dimples.

[gofastclint]

how does this translate to aircraft?

 

If you dimpled the surface of an aircraft what would happen?

 

Just a thought but if you used a smooth surface for all leading edges and a Dimpled all the trailing surfaces where the plane starts tapering away, would this allow the plane to slip through the air better?

 

Please no comments on price, looks or on being time consuming to do. I want the answers to be about the dynamics.

 

 

[Guest mike_perth]

From my limited aerodynamics experience (none!) dont the dimples change the air flow over the golf ball so the air "sticks" and remains laminar until the transition point at the "trailing edge" of the ball like a aerofoil would do anyway??

 

That my 2.2c (inc GST) worth anyway!

 

 

[Guest pelorus32]

Well GFC this is interesting.

 

Firstly Matt and Kaz had an aircraft - Dimples - that had had the hail treatment. This a/c is now owned by I think Greg at Port Macquarie. He's a member here and may care to comment.

 

The second thing is a mate and I were talking about something similar recently. Background: The footage of a golfball that I've seen suggests that the dimples cause them to oscillate in flight.

 

This mate, an ex heavy driver, has the view that cobblestoning - continuous chop style of turbulence - improved fuel consumption figures on heavy aircraft. He felt it was to do with the wings oscillating in the chop. Maybe a similar effect.

 

Regards

 

Mike

 

 

[Admin]

Speak to Matt or Greggf - Matt use to own Dimples and Gregg now has her

 

Recreational Flying

 

 

[gofastclint]

Not sure. one thing I have notice is that on some time trial bikes in the Tour de France is that the head stock features dimples to help the bike have less resistance and another thing, one of my friends had dimples on the bottom of his body board and is seemed to be quicker along the waves.

 

 

[gofastclint]

I think the size of the dimples has some effect,

 

I was in a car accident in which a V8 bock punched a 1 inch hole through the the back of my skull. It doesn't help me think any faster, but it does ge heccj ccje.... hmm waht waz i talkn about?

 

 

[Guest keeffe]

I have been thinking about mucking around with prop design.

 

I have thought also of the golf ball. I believe it reduces drag on the golf ball by reducing the wetted area of the ball, Less skin friction.

 

Its the same theory as one of those you beaut swimming suits the aussies use if you look at them under water there are bubbles stuck to them which effectively reduces the surface area touching the water.

 

Air pockets fill those little holes reducing friction.

 

I think that it could be incorporated into an aircraft, but imagine the work required. Less surface area less drag.

 

This link is info by the great Leeon Davis who made a 135 MPH machine out of 20 ponies the DA-11 READ IT! http://207.242.75.40/derbtech/davis.htm

 

 

[gofastclint]

I have been thinking about mucking around with prop design. I have thought also of the golf ball. I believe it reduces drag on the golf ball by reducing the wetted area of the ball, Less skin friction.

 

Its the same theory as one of those you beaut swimming suits the aussies use if you look at them under water there are bubbles stuck to them which effectively reduces the surface area touching the water.

 

Air pockets fill those little holes reducing friction.

 

I think that it could be incorporated into an aircraft, but imagine the work required. Less surface area less drag.

 

This link is info by the great Leeon Davis who made a 135 MPH machine out of 20 ponies the DA-11 READ IT! http://207.242.75.40/derbtech/davis.htm

It would be simple to cast a plate from a wax model and like they stamp coins stamp a sheet of aluminum once it was built you could let all your mates use it. just need a decent press.

 

 

[Guest keeffe]

It would reduce drag for sure and I am happy to work with anyone interested to explore this with me

 

Mike

 

 

[Tomo]

What about the wale...it's as rough as heck...but swims pretty fast.

 

Good discussion GFC...

 

 

[Tomo]

It would be simple to cast a plate from a wax model and like they stamp coins stamp a sheet of aluminum once it was built you could let all your mates use it. just need a decent press.

Or you could even just put the sheet down on some rough gravel and drive over it with something heavy... that make a goods dimples.

 

 

[gofastclint]

It would reduce drag for sure and I am happy to work with anyone interested to explore this with me Mike

sounds like a good idea. It would be good to see the faring of your drifted with dimples.

 

but i think they have the be in a correct ratio. like depth, distance apart and size.

 

 

[Guest keeffe]

I am planning on making simple mods to my drifter se reduce drag. For instance thin wheels etc etc cut the boom in half you know ;)

 

Another thing take the vs and vt commodore same drive train but the fuel efficiency is terrible compared, not to mention more gutless. The difference is extra body

 

Anyone know where I can get some thin wheels from? Maybe similar to the mt-03 wheels.

 

Mike

 

 

[Guest keeffe]

sounds like a good idea. It would be good to see the faring of your drifted with dimples.but i think they have the be in a correct ratio. like depth, distance apart and size.

Yes clint there would be a bit of science behind it but maybe you and me can revolutionise the AV world lol.

 

Mike

 

 

[Guest brentc]

There is a dimpled prop tape on the market that dramatically reduces the noise made by the prop.

 

 

[gofastclint]

fish have scales and sharks have rough skin and they have the least resistance in nature, 100 years of aviation may learn a bit for a billion years of evolution.

 

 

[Guest keeffe]

There are a lot of very simple answers to many complex questions, if we open our eyes.

 

Mike

 

 

[gofastclint]

There is a dimpled prop tape on the market that dramatically reduces the noise made by the prop.

That stuff is very needed at The Oaks, some of the guys have been testing some new props and they seem to be working well but the sound is too much.

 

 

[Guest keeffe]

Clint there was a drifter down there at the oaks partly owned by a guy that passed away is that still there collecting dust?

 

Mike

 

 

[gofastclint]

Clint there was a drifter down there at the oaks partly owned by a guy that passed away is that still there collecting dust?Mike

I didn't notice one there, but I'm going out there on the weekend, I will have a look for you.

 

 

[Guest keeffe]

It was down in the hangar where John had his Jab and Bantam.

 

Mike

 

 

[Guest keeffe]

http://youtube.com/watch?v=-oHMEvZCWcY

 

Golf ball dimple explanation

 

Mike

 

 

[Guest Maj Millard]

Did read an article some years ago about the dimple tape that BRENTC mentioned. They were using it on both props, and wings to reduce resistance. It was placed on the top surface at the highest point approx 15-20 % back from Leading edge.

 

Apparently it worked ok, especially on props. I have seen similar tapes used on glider wings, in the same position on the wings, I would imagine for the same reason ??.....

 

 

[jcamp]

IIRC Key point with dimples/not dimples relates to Reynolds Number (RN - roughly =10,000*size in feet*knots) a golf ball is in the 10,000 range and drag is due to viscousity hence dimples help. On a cannon ball they wouldn't.

 

Model a/c at 100,000, gliders at 500,000 GA at 1,000,000+ and airliners at 10,000,000 (obviously with variations due to what and where in the envelope they are) tend to have considerable variations in Cl and Cd curves even if they have the same airfoils. Hence different airfoils are used. A quick example on the 23012 (eg DC3) airfoil is at:

 

http://naca.larc.nasa.gov/search.jsp?R=998183&id=7&qs=Ntt%3D23012%26Ntk%3Dall%26Ntx%3Dmode%2520matchall%26N%3D0%26Ns%3DHarvestDate%257c1

 

There is a noticable difference between 8,000,000 and 3,600,000 and would probably be pretty bad (unsuitable) on a model at say 360,000.

 

This was a big problem in the early days (pre mid 30's) as it wasn't really appreciated and was one of the reasons early wind tunnels tended to give misleading results. Classic example was the supposed theorectical inability of the bumblebee to fly, they didn't allow for the low RN and so got the wrong answer (the scientists not the bumblebee)

 

 

[gofastclint]

So dimples will work just on only certain points of the aircraft.