Planks- R-Swept, Ellipsio- miniplank 1S brushless - Rear motor FPV - RC Groups
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Mar 28, 2016, 12:53 PM
Laughs at un-boxing videos...
basicguy's Avatar
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Planks- R-Swept, Ellipsio- miniplank 1S brushless - Rear motor FPV


I posted something about the first plankwing on the KFm subforum.

https://www.rcgroups.com/forums/show...3#post34346942

Built my second wing. Both are 30" spans 9.25-9.5" chords. and 2730 type 24 gram motors.

The first one weighs about 250 grams with a small battery. The second 210 grams. Went from 9 gram servos to 4.4 gram. Put in a 4mm carbon tube spar in place of the 1/4" dowel rod. I used Whitcomb type winglets, slightly toed out. Trying to enhance flat glide and lift.

The wing is a cross between a KFm4 wing and an Armin.
Needs some finish work on the nacelle and winglets.

Here it is on it's maiden:
Plank_2 (1 min 53 sec)

Notice how nice it glides. You can still hear the prop freewheeling, probably will put on a folder.

I have some build pics but it is too nice to be inside any longer.
Last edited by basicguy; Jan 29, 2017 at 03:25 PM.
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Mar 28, 2016, 02:12 PM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Nice Flier !!!
Mar 28, 2016, 02:14 PM
Zen in the art of foam
djacob7's Avatar
Flies great!
Are you sure the winglets are toed out? For yaw stability they're usually toed in, i.e. the front of the winglet is toed inwards.
Mar 28, 2016, 05:22 PM
Registered User
elewon's Avatar
Quote:
Originally Posted by basicguy
...
Notice how nice it glides. You can still hear the prop freewheeling, probably will put on a folder.
You don't need folding prop, unless you want to reduce the last oz of drag. You will see noticeable improvement in glide even with regular prop if you turn on ESC braking.
Mar 29, 2016, 07:56 AM
Laughs at un-boxing videos...
basicguy's Avatar
Here are some build ideas.
Using a single sheet of foam board cut off a 10.5" piece then a 2" slice and lastly a 1". Remove the paper from one side of the 10.5" part and all of the paper from the smaller pieces.

Glue the 2" to the remaining 6.5" piece overlapping by about 3/8"


Using a 4 mm tube glue it on top here:


Fold the 10.5" part in half (I use a piece of 1/2" cpvc water pipe as a form.) Glue one side of the 2" piece also glue the carbon rod.

I have a good supply of lead weights to keep it all together while the white foaming gorilla glue sets. Then I glue the back ends together to form the airfoil. (no picture). Once cured, I remove the remaining paper and iron on package tape.

Here is the finished airfoil on profile.


Seeing this photo makes me think that my next one will have a different construction method.

I followed a Nasa paper on the Whitcomb winglets for this one. He toed out the winglets (not in) Here is the article that I saw: http://www.enu.kz/repository/2010/AIAA-2010-4224.pdf

Made a little square of 1/4" plywood for a motor mount. and used 3/32" balsa for the "fuselage". This is the tool I use to transfer the pattern:

Last edited by basicguy; Mar 29, 2016 at 08:29 AM.
Mar 29, 2016, 02:59 PM
Registered User
Dickeroo's Avatar
Quote:
Originally Posted by basicguy
I posted something about the first plankwing on the KFm subforum.

https://www.rcgroups.com/forums/show...3#post34346942

Built my second wing. Both are 30" spans 9.25-9.5" chords. and 2730 type 24 gram motors.

The first one weighs about 250 grams with a small battery. The second 210 grams. Went from 9 gram servos to 4.4 gram. Put in a 4mm carbon tube spar in place of the 1/4" dowel rod. I used Whitcomb type winglets, slightly toed out. Trying to enhance flat glide and lift.

The wing is a cross between a KFm4 wing and an Armin.
Needs some finish work on the nacelle and winglets.

Here it is on it's maiden:
https://youtu.be/3zsjqBbxhyk
Notice how nice it glides. You can still hear the prop freewheeling, probably will put on a folder.

I have some build pics but it is too nice to be inside any longer.
BasicGuy....

It would be very interesting to see how this plank wing would fly if you eliminated the KFm4 airfoil. How much of a difference in flying would there be?

Are you game to try?

~ Dick
Mar 29, 2016, 04:05 PM
Laughs at un-boxing videos...
basicguy's Avatar
Dick,
Do you mean build one as a flat plate wing?
Mar 29, 2016, 09:05 PM
Registered User
Dickeroo's Avatar
Quote:
Originally Posted by basicguy
Dick,
Do you mean build one as a flat plate wing?
Mm

BasicGuy.....

No, I meant build one as just an Armin wing. It would just be interesting to see if there would be any difference in the handling or characteristics of the wing without having the steps.

~ Dick
Mar 30, 2016, 06:22 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
What’s an Armin wing , just a foam wing with ribs huh .... Who is Armin and why does he claim something been done for years ... ???
Mar 30, 2016, 09:33 AM
Registered User
Dickeroo's Avatar
Quote:
Originally Posted by gpw
What’s an Armin wing , just a foam wing with ribs huh .... Who is Armin and why does he claim something been done for years ... ???
GPW ....

Ed from Experimental Air designed an easy to make cambered airfoil with simple techniques for building it. You can check out his thread in the Scratchbuilt section. He called it the Armin wing.

~ Dick
Mar 30, 2016, 09:40 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Thanks Dick , it gets confusing keeping up with the new names ...
Mar 30, 2016, 12:21 PM
Laughs at un-boxing videos...
basicguy's Avatar
Got a start on an Armin type plank.

Yeah who exactly is Armin. Have built them in the past, but always flat bottomed. Trying to make this one symmetrical without a warp.
Mar 30, 2016, 06:12 PM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Basic , use a small spacer under the TE when you assemble it ..
Mar 30, 2016, 06:23 PM
Build straight - Fly twisty
Whiskers's Avatar
Armin is the son of Experimental Airlines Ed who named the wing structure in his honor.
Mar 30, 2016, 07:27 PM
Laughs at un-boxing videos...
basicguy's Avatar
I am using 4, 3 pound bars of bullet lead. Have built up structures like a spar and clamp them securely with the lead bars. Careful handling keeps me from denting the foam.

I have the elevon hinges gluing into the wing. I splurged and used store bought hinges. Once dry I will remove the paper from the outer surface and figure out the fuselage.

This method is using about the same amount of material so I expect the weight to be similar.

Cool way to put your son's name on something.