winglets
 

Why no winglets on Dash 8 and ATR....or are they in the testing stage..just curious.
tks

I dunno, why no winglets on a C172?

!. they already have a hi aspect ratio wing
2. they don't fly high enough to warrant them

B1900 has winglets and it flies at the same altitudes...

Winglets
 

The Robinson modification add winglets to the 172 .

The winglets on the 172 are attached to the engine cowls, I believe these are used to enhance short field take off capability. I think the original poster was talking about winglets on the wing tip. Some manufacturers believe that a well designed wingtip i.e. with sharp edges is just as effective as a wing with winglets. You probably could develop winglets for an ATR or Dash 8, however it will be a trade off between development cost vs benefits of the reduction in induced drag. Hope this helps.
CL.

The Fokker 50 has the wingtips a bit curled; surely not big enough to be called Winglets. The company therefore dubbed them "Foklets".
For real.

winglets
 

I saw a commander with them,so I had to ask
regards

There is an argument that a properly designed wing doesn't need winglets, or any other add-ons (like stall strips, fences, etc.)

Each 'fix' is an attempt by the aerodynamicists to compensate for design constraints that other people impose, preventing the optimum aerodynamic design from being implemented.

Would that argument also pertain to other variations in the wings profile? For example, would a properly designed wing have no need to have variable camber, twist, sweep, chord to wingspan ratio, nor vertical angle (Burt Rutan's boomerang comes to mind).

Good question, B350 has them also.

Yes!

If the wing is designed with one thing in mind. I.e. to produce x lift at y speed then the design would be very simple. But if you give the designer a range of weights speeds altitudes with constraints on pitching moments etc. etc. etc then the Wing becomes a compromise and may need tweaks like vortex generators, turbulators, boundary layer fences and "Winglets". The commercial department may ask for a certain look too. "If all the latest jets have winglets we should have them"

So all of these are used for a reason but all for the same reason and there are many variations that could achieve the same results.

Wing = Compromise.

see #1. the aspect ratio on the 1900 is quite a bit less, and they didn't want to redesign the wing jigs, ergo need more lift. Also the dash carries quite a bit lower wing loading. the 350 gets even more performance as it flies higher at a reduced IAS. as FEH said compromise

The what? Are we talking about the Cessna 172 here, or is there another 172? :confused:

You probably are thinking of the wren 260 a cessna 182 with a canard and some other mods.
http://www.katmai-260se.com/documents/brochure.pdf

It would look weird too...

Yes, you are correct it was the C182P, it does have cannards. I mentioned before that some manufacturers believe a well designed wingtip does not need winglets. This is not to say that wings with winglets are poorly designed.
As FE hoppy has said, wing design is a compromise. Winglets give the biggest advantage to long range aircraft, which fly at relatively constant speed. However short haul a/c can still benefit, but not to the same degree as their long range counterparts. The other reason for winglets is to reduce wing span, ideal for a/c which have trouble fitting into gates.
CL