Side Force Generators question (SFG's)
03-14-2014, 07:52 PM
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Side Force Generators question (SFG's)
I posted this in the 3D forum too but you guys might have an idea.... I have the new UCanDo SF and just started the build. It has SFG's that bolt to the wingtips, nothing unusual here. What is odd though is that the SFG's and wingtips are not parallel to the fuselage. The SFG's (and wingtips) point in towards the nose of the airplane quite a bit, maybe more than 5 degrees. What are they thinking? Anyone ever seen SFG's that have tow in like that? Looks like it would cause a lot of drag in straight flight! Ideas anyone? Thanks.
03-16-2014, 12:13 PM
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On our models a little drag is not a big deal. Especially on a 3D model where the model is intended to fly a slow speeds for the whole flight. After all do you really want to hit "mach speed" and find those big control surfaces fluttering like flags in a breeze? So the priorities for things like SFG's is aimed at other features than low drag.
I'm going to assume that the toe in angle was set based on how it balances the side lift during knife edge flight. A toe in angle would mean that the lower SFG plate is going to be positively angled and thus generate more lift at a point somewhat ahead of the CG vs the other plate that will be more feathered to the air flow and behind the CG. This has likely been all set up through in flight trials. So you would be trying to second guess the designer and test flyer that originally determined the angle.
Since it's a bolt on part you COULD play around with some insertable wedges that can be used to reduce and increase the toe in and play with the setting yourself.
As for the use of toe in on SFG's if you look around at some of the indoor slow flying 3D models you'll see not only radical angles in SFG's but even drag plates mounted on the trailing edges of ailerons. The idea is to USE the drag to slow the downlines of the patterns. Again they are using drag as a tool to control how the plane flies.
That make sense?
I'm going to assume that the toe in angle was set based on how it balances the side lift during knife edge flight. A toe in angle would mean that the lower SFG plate is going to be positively angled and thus generate more lift at a point somewhat ahead of the CG vs the other plate that will be more feathered to the air flow and behind the CG. This has likely been all set up through in flight trials. So you would be trying to second guess the designer and test flyer that originally determined the angle.
Since it's a bolt on part you COULD play around with some insertable wedges that can be used to reduce and increase the toe in and play with the setting yourself.
As for the use of toe in on SFG's if you look around at some of the indoor slow flying 3D models you'll see not only radical angles in SFG's but even drag plates mounted on the trailing edges of ailerons. The idea is to USE the drag to slow the downlines of the patterns. Again they are using drag as a tool to control how the plane flies.
That make sense?
03-16-2014, 09:56 PM
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Absolutely makes sense! Thanks a bunch. Early reports are that this plane is a great flyer and 3D plane. I have seen the drag plates on the indoor models but have not seen the angled SFG's yet. I'll take a look at that. I'm assuming they would be towed in like these are. I feel better.....
, thanks again.
, thanks again.
