Hotwire tapering LE, TE or both? - RC Groups
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Oct 06, 2017, 12:26 PM
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Bringamosa's Avatar
Discussion

Hotwire tapering LE, TE or both?


My next wing will be a hotwire cut Styrofoam wing. The idea is to have one static point where i have my hotwire attached and on the other side the template. I'll create two winghalfs this way. This method will create a tapered wing.

Now there will be 3 options for the taper. Only the leading edge, only the trailing edge, or both.

What we'll be the different characteristics of these wings, while using the clark y airfoil?
Last edited by Bringamosa; Oct 06, 2017 at 04:22 PM.
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Oct 06, 2017, 02:15 PM
An itch?. Scratch build.
eflightray's Avatar
Quote:
Originally Posted by Bringamosa
.................................

What we'll be the different characteristics of these wings, while using the clark y airfoil?
No noticeable difference in flight for model size planes, some just look better on certain planes.

Ray.
Oct 06, 2017, 02:31 PM
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Bringamosa's Avatar
Allright, so for some motorised, gliderish, sloaparing plane it fires not matter to much?
Oct 06, 2017, 02:53 PM
An itch?. Scratch build.
eflightray's Avatar
There is a lot more to a successful flying machine than whether the wing has any taper.

It's so much easier to follow what has already been successfully designed and flown, (copy someone else's design)), then perhaps on a second version try different ideas, swept back wings, different airfoil, etc, to see what the effect is.

It depends on what you want to achieve, and your experience.
Oct 06, 2017, 02:56 PM
B for Bruce
BMatthews's Avatar
Quote:
....where i have my hour wrote attached.....
I'm not sure if it was the translation you did or your english word selection was off. But these words should have been "hot wire".

I've done some foam wings for control line combat models where the one end was fixed to a pivot and it worked out nicely. Depending on how tapered they are it CAN make a difference. But for a taper of 200mm to 150mm the differences from all the taper at the LE or TE or if you split the amount simply won't really be detectable in flight. So pick the one you like the looks of .

One thing that it might affect depending on the design is the CG location on the wing. If you want a long nose the swept back LE might cause the model to need a little tail weight. On the other hand a very short nose with the straight LE might require a little more nose weight than if it had the style with the straight TE.
Oct 06, 2017, 04:32 PM
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Bringamosa's Avatar
Thanks BMatthews for the correction. Indeed my tablet did some weird auto correction. I thought i checked my writing before posting, English is not my native language but i should have caught that.

So like you said, performance does not mather too much, cg might. That might be the deciding factor for me then.

Eflightray, i understand the Idea of taking a working plan and design and go on from there. I have some ideas from the forums here. Since i don't have a bow for my hotwire i was wondering what the difference would be if i used the pivoting hotwire method and if there would be mayor differences with the diffrent tapered wings.

I appreciate your answers, Thanks a lot!
Oct 07, 2017, 12:09 PM
B for Bruce
BMatthews's Avatar
Quote:
So like you said, performance does not mather too much, cg might. That might be the deciding factor for me then.
Only in that the way it tapers shifts the wing area forward or back in relation to the root rib. And it would only be an issue if the nose of your design is longer or shorter in a poor combination with how the wing area is positioned. For a "normal" layout the taper won't really matter at all.

Remember that the CG is based on the Mean Aerodynamic Chord of the wing. The forward or swept taper just moves the MAC by a little which means the required place for the CG shifts a portion of that.
Oct 11, 2017, 09:55 AM
Registered User
You'll find that you need to move the pivot point farther away than the theoretical distance to get the same tip chord. The wire is moving slower at the tip leaving a larger kerf which results in a smaller chord than anticipated.
Oct 11, 2017, 02:32 PM
flyin' fool
goldguy's Avatar
Leading edge tapper has a dihedral effect.

Also, check here for more info ................https://www.rcgroups.com/forums/show...haracteristics
Oct 11, 2017, 03:58 PM
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Bringamosa's Avatar
Thanks a lot. For now i tried taper on TE
Oct 11, 2017, 09:46 PM
flyin' fool
goldguy's Avatar
Check out these picture to see what other designers use................... https://www.google.ca/search?q=class...w=1024&bih=646
Oct 12, 2017, 03:11 AM
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Bringamosa's Avatar
Quote:
Originally Posted by goldguy
Check out these picture to see what other designers use................... https://www.google.ca/search?q=class...w=1024&bih=646
Looks like a bit of all three and some with no taper ead some backward or forward swept


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