Fuse Structure... A big difference in performance?

[GreenAce92]

So im the kind of guy that enjoys a sweet looking bird, and im curious as to whether or not there is a massive performance difference when comparing an F3B(sleek round tubular fuse) to something like one of these:

https://www.fiddlersgreen.net/aircraft/SchweizerTG-2/IMAGES/Schweizer-TG2-preflight.jpg

I mean can they still both have the same soaring performance or not? im thinking that the F3B ships are extremely streamlined and Fast sooo..... because im designing a foam sailplane(not being launched by winch's but a slow hi-start) and i want a nice performance for thermalling but i also want the look there is nothing wrong with the looks of an F3B ship but i cant make one that thin and without glassing/kevlar expect it to be as strong what do you guys think?

I was thinking of building a sailplane like the pic above by designing it on google unfolding the parts printing them and building it from blue foam, wouldn't be too hard but i dont have blue foam at the moment but i probably should just try for an F3 series type fuse i do have the glassing

Also are those sailplanes(like the pic above) still popular today? or are we getting into more of the DL100 or Stemme 10 look where its just a tear drop canopy and then sleek thin everywhere else

[John Walter]

The pic is a TG-2 sailplane trainer from the 30's. There is a build thread of a 1/10th scale version here:

http://www.rcgroups.com/forums/showthread.php?t=495461&highlight=tg+2

One certainly gives up performance to use such a large fuse, but unless one is flying F3X type events, there is no need to build a fuse with such minimal cross-section.

[GreenAce92]

Wow what a nice bird! beautiful!!!

[GreenAce92]

Also just another question does down wards facing/pointing wing tips help improve wings at all? I'm planning on putting down facing winglets(correct term) on a hi-dihedral R/E model. So that even though you are getting less lift compared to a flat wing with the angled wing, that air rushing around the underneath of the wing will still be forced downwards which i assume should help in making more lift?

[prodjx]

I think you are refering to Hoener wing tip's, the most modern A/C that has them is an A-10 Warthog and I'm sure there a number of sport A/C that have them as well. My custom built Consortium vintage HLG has them and they do look neat.

[GreenAce92]

But are they helpful?

[prodjx]

One of the claim's was that they increase lift. They look neat too.

[Anker]

But are they helpful?

The most efficient is a longer wingtip. Winglets and tiplets only make sense when there's a reason why a longer wing can't be made. For example, if there's a class limitation on wing span, tiplets may make sense. On commercial airliners the tiplets are usually there either because they are a retrofit or because the wing span otherwise may make it difficult to park at gates.

The most efficient wing is a pure elliptical wing with no "adornments".

Anker

[Anker]

Many years ago I built removable tiplets for my Airtronics Legend and did some test flights with tiplets on only one tip, the theory being that the plane should bank away from the tiplet if they reduced drag or improved lift. I did the test flights on a dead calm early morning and did see a tendency to slowly turn away from the tip with the tiplets. The improvement was very, very slight.

Anker

[GreenAce92]

Ahh i see well for me there is a limit lol because i dont have long enough CF spars but thats not much of a problem

thanks for the great info!

[ThermalSeeker]

Welcome to the world of designing. In a single word...it's compromise. If you like the looks of a scale ship then that's what you should design. If you want the best performing glider that you can build then that's another thing.

For climbing in a thermal or light air slope soaring the differences will be minimal. Once the wind picks up on the slope or you want to penetrate back upwind after having drifted downwind in a thermal...then you'll see the difference.

Mike


.....I was thinking of building a sailplane like the pic above by designing it on google unfolding the parts printing them and building it from blue foam, wouldn't be too hard but i dont have blue foam at the moment but i probably should just try for an F3 series type fuse i do have the glassing...........

[Lance Prior]

Here is a graph that shows how much drag various parts of a glider have.

http://www.mh-aerotools.de/airfoils/images/linkage6.gif

It is from this web site.

http://www.mh-aerotools.de/airfoils/index.htm

[target]

Ahh i see well for me there is a limit lol because i dont have long enough CF spars but thats not much of a problem

thanks for the great info!


CR spars really don't need to go to the very tip of the wing, unless you are building a DLG.
The most stress a wing tip sees generally is when the pilot forces it to be the first part of the plane to touch the ground. :rolleyes:
So don't do that!

In a bagged wing, the last 6-8" are fine with out a spar, IMO.
Anker could expand on that, though.

I know that tip fences were popular on slope planes back in the early eighties, but there must be a reason that they aren't now, right??

R,
Target

[Anker]

CR spars really don't need to go to the very tip of the wing, unless you are building a DLG.
The most stress a wing tip sees generally is when the pilot forces it to be the first part of the plane to touch the ground. :rolleyes:
So don't do that!

In a bagged wing, the last 6-8" are fine with out a spar, IMO.
Anker could expand on that, though.

I know that tip fences were popular on slope planes back in the early eighties, but there must be a reason that they aren't now, right??

R,
Target

I agree with Target/Anker