Anticept Posted April 17, 2015 Author Report Share Posted April 17, 2015 That's a tiny looking trim tab. Maybe it's to assist in centering it. Link to comment Share on other sites More sharing options...
Doug Hereford Posted April 17, 2015 Report Share Posted April 17, 2015 Anticept, I think you might be right. (Similar to that King Air aileron TE bump). An important point to take away might be, that some things that don't make obvious sense, or seem inconsequential might have a very important impact on the safe operation of the aircraft. I personally think that things like this should be in mind whenever someone thinks that their purposed alteration is "minor". Don't worry about those pesky little "what-ever's". Just alter-away. Doug Hereford Link to comment Share on other sites More sharing options...
GlennM Posted April 27, 2015 Report Share Posted April 27, 2015 Speaking of trim tabs... The trim tab on the elevator of the Skycatcher has right angle extensions on both the top and bottom of the trailing edge. Best photo I can find: Seems inefficient, and I can't figure out the purpose. Anyone? That is a Gurney flap. Increases the pressure differential and keeps the boundary layer attached for more efficiency. Used upside down on race cars for downforce. Link to comment Share on other sites More sharing options...
FastEddieB Posted April 27, 2015 Report Share Posted April 27, 2015 That is a Gurney flap. Increases the pressure differential and keeps the boundary layer attached for more efficiency. Used upside down on race cars for downforce. It's great to learn something new! Thanks! Still trying to wrap my brain around how they work, though! Link to comment Share on other sites More sharing options...
Jacques Posted April 27, 2015 Report Share Posted April 27, 2015 ! Still trying to wrap my brain around how they work, though! http://en.wikipedia.org/wiki/Gurney_flap Link to comment Share on other sites More sharing options...
FastEddieB Posted April 27, 2015 Report Share Posted April 27, 2015 I was just perusing that page. Great minds and all that. But I'm STILL trying to wrap my brain around how they work! And if they work so well, why aren't they everywhere? Link to comment Share on other sites More sharing options...
WmInce Posted April 27, 2015 Report Share Posted April 27, 2015 Come to think of it, the bottom side of the Huey (UH-1) horizontal stabilizer had one of those. It protruded down (on the bottom surface, at the trailing edge) about 1/2 inch.Maybe sandpiper can chime in on that also.How about it John? Link to comment Share on other sites More sharing options...
Doug G. Posted April 27, 2015 Report Share Posted April 27, 2015 But this is both up and down, not quite the same as a Gurney, is it? Link to comment Share on other sites More sharing options...
FastEddieB Posted April 27, 2015 Report Share Posted April 27, 2015 The wiki article mentions double Gurneys. Has an image of one on a helicopter tail plane. Seems like they would cancel out and just increase drag, but apparently they can be effective in both directions. Says they do generally increase drag, but with some fat airfoils may actually decrease it. Weird. Link to comment Share on other sites More sharing options...
Doug G. Posted April 27, 2015 Report Share Posted April 27, 2015 On a trim tab, it would seem that the edge more in the airstream would cause greater down pressure. Possibly it allows the use of a smaller tab with the same effectiveness? Link to comment Share on other sites More sharing options...
sandpiper Posted April 27, 2015 Report Share Posted April 27, 2015 Come to think of it, the bottom side of the Huey (UH-1) horizontal stabilizer had one of those. It protruded down (on the bottom surface, at the trailing edge) about 1/2 inch. Maybe sandpiper can chime in on that also. How about it John? Bill, I haven't flown a Huey since 1978. Thats 37 years. I just don't remember. Sorry. I looked for some pictures but came up blank. Link to comment Share on other sites More sharing options...
WmInce Posted April 27, 2015 Report Share Posted April 27, 2015 Bill, I haven't flown a Huey since 1978. Thats 37 years. I just don't remember. Sorry. I looked for some pictures but came up blank. Thanks anyway John. I instructed on it for many years and vividly remember it. Last flight 1988. Looking forward to meeting you in person at Page this year. . . . Link to comment Share on other sites More sharing options...
GlennM Posted April 28, 2015 Report Share Posted April 28, 2015 http://allamericanracers.com/the-gurney-flap/ has a good explanation down at the bottom. Link to comment Share on other sites More sharing options...
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