Foamy VNE / Slowing down a precision foamy

[Matchless]

A bunch of people have commented about how the downlines in the Flying Giants Fliton Indoor IMAC Competition feel fast...... Well, the truth is, a clean standard foamy will accelerate pretty quickly on a downline. Think about it, there is very little frontal area to a foamy, just the motor, servos and some 3mm thick 'faces' and leading edges..... All that adds up to an airplane that will accelerate pretty quickly

Making the airplane lighter will help. We all know that a pound of lead and a pound of feathers weighs the same thing, but the pound of feathers will inevitably have more drag and so the drag will slow it down more on a downline than something without as much drag. Of course making it lighter will in general make it fly better as well.....

If you watched the ETOC in 06, or have downloaded any recent videos from European F3P competitions (I highly encourage you to do so...) you'll notice that many if not most of the competitors had 'aerodynamic aids' of some sort on their airframe to slow it down. Some (but not all) of the aerodynamic aids included:

Perforated trailing edges (round holes and alternating triangles)
Drag Strips on trailing edges
Angled Side Force Generators
Angled Cabanes (for biplanes)

For my Indoor IMAC Yak, I was verrrry pleased with its performance indoors. It flies a crisp line, handles with basically no coupling whatsoever, and flies very slowly. However, I want it to fly the downlines a little better(slower) so I can hit the downline maneuvers better.

Since the FGFIIC does not stipulate that the airplane has to be scale, I figured I'd add several aids to it to slow it down. I did not want to make it terribly un-scale-like though, so I tried to keep them simple and unobtrusive. I am using details that I had already experimented with on my Sentinel, so I had some baseline info going in. The reason I'm putting up this thread is so you can do the same to your ShockFlyer, or other foamy and compete in the contest. More competitors = More fun

I started with my IMAC Yak55 by adding drag holes in the trailing edges of each flying surface. You can see in the pics where I located them. Why? So far that seems like the best location. There may be a better location, or a better sized or shaped drag hole, but I have not found it yet. These seem to slow the airplane significantly when the surface is deflected (like in a downline snap )(See Pics Below)

Next up, I added a drag strip to the trailing edge of the Rudder and the trailing edge of each aileron out near the tip. Again, size is based on what worked for my airframe. I had some on an earlier airframe that were much larger. I did not like how much they slowed the airplane. They also seemed to make it wallow somewhat, so I removed them.... Some guidelines: On ailerons, make them the same size. Pretty self explanatory why unless you like flying in circles... For the rudder, if your rudder trailing edge has sweep to it, it will likely have a slight pitching effect on the airplane that you'll have to trim out (it has on every one I've done yet). Go with the size you like. Don't be afraid to try different sizes, it only takes a small depron scrap to make one. (See Pics Below)

Finally, I put angled SFG's on my plane. The first place I saw these was on Martin Mueller's Manta (a top notch, contest winning design in Europe). For my Yak, I copied the top of the rudder and duplicated it 4 times. Measure where you locate them and obviously you need to put them on in the same location and the same angle. The angle is obviously up for debate, but I've found that about 8-12 degrees from the path of flight is a good starting point. Again, try a couple different sizes and angles to decide on a final setting. (See Pics Below)

I hope this helps some people 'slow it down' for the contest.

[Animal Jesky]

The angled SFG's slow the plane down but also add stability. I have been running these for almost a year and they are incredible. I actually put mine to about a 30 degree angle and found it works great.

To test I just cut the sfg and made it a snug fit on the aileron so I could vary the angle without gluing.

[Matchless]

	Quote:
	To test I just cut the sfg and made it a snug fit on the aileron so I could vary the angle without gluing.

Thats a good idea Animal. I've been tack gluing mine in place an moving them around until I find the best location, but a friction fit would definitely be 'easier' on the aileron. I also noticed the stabilizing factor in my usage of them......

On the Yak, I was trying to stick to somewhat of a 'scale' appearance, so I made them smaller. On my non scale designs, I make them significantly larger (for greater effect).

[chitty3d]

Matchless what did you do to the leading edge of this plane and do you guys thing that mono wings have the best F3P capabilities??
Chitty3d

[SleepyC]

Animal .. have a picture of your install?

[Matchless]

	Quote:
	Matchless what did you do to the leading edge of this plane and do you guys thing that mono wings have the best F3P capabilities??

The leading edge of my Yak has a 2mm doubler on top and bottom, sanded round on the front. Attached with 3M #77 spray. I found that it gets rid of a little of the 'pitchiness' that I was getting with my first monoplane F3P ships. This also doubles as a wing stiffener and a mounting point for the carbon wing braces (underside).

IMO, I think the Mono vs Biplane question is somewhat a Ford vs Chevy debate for the most part. Both have their advantages. I'm flying mono's because I can build one much faster and there is less setup to mess with. Bipes have an advantage in side area effectiveness, drag and aileron area. For this particular contest, bipes might have an advantage in unlimited and advanced(bipes took top placings in the ETOC last year), and monos might have it for FAI F3P-A (monos have taken most of the recent top placings in Euro contests), but I have not completely convinced myself of that- Personally, I'm gonna keep flying my monos....

[DA2000]

Great Stuff!!

Thanks Matchless (you too Andrew)

[chitty3d]

Good thought thanks looking forward to seeing what everybody is coming with this season @ the chitty3d indoor event!!

[chitty3d]

Matchless, I saw that you have a break on the rudder... I found that it is effective in foward flight and downlines but is unpredictable in and up line climb I cant seem to ever get the rudder trimmed out HUH!!

[Animal Jesky]

Sleepy,

I will take some pics tonight of the foamy. I'm hardly working, I mean working hard here at work. I will upload when we go and have our foamy night fly in.

Dan,

You guys doing any foamy flying out there? BTW, Heard you got a new plane coming

Andrew

[Matchless]

	Quote:
	Matchless, I saw that you have a break on the rudder... I found that it is effective in foward flight and downlines but is unpredictable in and up line climb I cant seem to ever get the rudder trimmed out HUH!!

I'll have to think on that one a bit...... It sounds like the same thing I went through when I put drag strips on that were too big. I would get a wallowing effect each time.

I'll watch my birds tonite to see if there is any similar thing going on with them.....

[treym7]

Check out the Jason Noll / Fancy Foam Vrolet for some ideas also, very good looking plane. Has some of the things that are being mentioned here used in its design. There are some pics here: http://www.flyinggiants.com/forums/f...am-vrolet.html and also here: http://www.fancyfoam.com/VroletF3P.htm
Trey

[Matchless]

You beat me to it Trey : ) . Jason's airplanes were the first place I saw the alternating triangular perforations in the trailing edge. The f3P version of his Vrolet has a competition pedigree and does what it says it will.

[xtremeRCpilot]

Great Info!!! Finally someone has revealled some secrets to us basement flyers. I cant wait to give this a try on some of my models. Thanks!!!

[Matchless]

Well, here is some more to add regarding the drag aids......
I mentioned in my earlier descriptions how important it is to make them equal sizes on both sides of the plane and how critical alignment is for the angled SFG's.

Apparently I did not do as good a job at practicing what I preached on the SFG's for my Yak. When we went to indoor night, I first worked on trimming my airplane, then went on to practicing the FGFIC. Unfortunately, I could not get the Yak to track right (yaw problem) Repeated attempts to get it trimmed did not get it tracking as smoothly as I wanted.

So last night, I decided to check out the alignment of the little bird and see what was wrong. Measurements of my drag strips told me they were correct. They were also perfectly centered on the trailing edge of the surface. Same goes for the strip on my rudder. Then I checked my SFG's against each other......The left size SFG's were about 3 degrees further out than the right. Since I had only tacked them on, I popped them loose and reattached using an angle jig made from a depron scrap. --- Instant huge improvement! I'm guessing they slid a little bit on the surface when I mounted them.

Chitty, I did not find any wobble like you described on uplines. My guess is you may have them too big....... Experimenting is really the only way to find out...