Golf Balls travel further because of dimples.

[Tomo]

Here is some interesting info...

 

http://www.dimpletape.com/article.htm

 

 

[sain]

RE: Shark Skin - isn't it only rough in one direction (backwards), and very smooth in the other.

 

I'd suggest playing around with some CFD (computational fluid dynamics) simulation software to get a feel for whats really (well, probably really) happening.

 

try OpenFVM, its free so it wont cost you anything but time to play with:

 

http://openfvm.sourceforge.net/

 

Check the gallery on that site for some idea of what it can do.

 

 

[skydog]

Sharks skin

 

Sharks skin covering on an airplane!

 

sure puts another meaning to comment "this slippery little plane if you are not careful can easily bite you"

 

 

[gofastclint]

Sharks skin covering on an airplane!sure puts another meaning to comment "this slippery little plane if you are not careful can easily bite you"

Hahahahaha!

 

 

[Yenn]

The reason for the dimples on a golf ball is that there is no consistent leading edge. If the golf ball had an airfoil shape and was always hit in the same way to keep the leading edge leading, there would be no need for dimples.

 

If you want dimples on your plane I suggest you build a round plane with a means of making it spin randomly.

 

 

[Guest Redair]

Now the idea of a dimpled wing and ducted thrust from a compressor! Now that could be worthy of investigation.

 

However, and I submit this humble point because everyone else seems to have overlooked it... but a golf ball gets a mighty whack up its backside to proppel it... are you thinking of a similar thrust method for a dimpled aircraft?

 

Redair.

 

 

[youngmic]

Jcamp was on the money.

 

All to do with Reynolds numbers, low RN's it helps, and high RN's it hinders.

 

Low RN's = small chord, low speed and thick air, high RN's the opposite.

 

A classic example is the prop on a Trojan T28, first 3rd of the blade from the hub is a rough surface and the remainining is smooth. Racing outboard legs another example, but not their props, they're smooth.

 

Shark skin and ribblett finish is a different principle, similar but different. Turbecules another very recent and interesting twist, natures way of doing VG's properly.

 

Gear legs will benefit but not much else on a typical aircraft

 

 

[gofastclint]

Jcamp was on the money.All to do with Reynolds numbers, low RN's it helps, and high RN's it hinders.

 

Low RN's = small chord, low speed and thick air, high RN's the opposite.

 

A classic example is the prop on a Trojan T28, first 3rd of the blade from the hub is a rough surface and the remainining is smooth. Racing outboard legs another example, but not their props, they're smooth.

 

Shark skin and ribblett finish is a different principle, similar but different. Turbecules another very recent and interesting twist, natures way of doing VG's properly.

 

Gear legs will benefit but not much else on a typical aircraft

If a golf ball travels up to 2.5 times farther due to the dimples, then adding dimples to the legs on my landing gear is a great idea. If it only increases the efficency by half that, then I see it as a massive gain. We all know why landing gear is retractable on most larger aircraft.

 

 

[geoffreywh]

When I lived in Germany there were motorcycle crash helmets available that were dimpled.( teaspoon sized dimples) . I saw independent tests that showed they required less neck effort to turn the head in a 150kph wind (funny how at 150kph you can be a law abiding citizen in Germany and a antisocial bloody murderer here!) Anyway don't get me started. But the headgear caused less pressure on the neck muscles at high speed and were very popular.....