Planks- R-Swept, Ellipsio- miniplank 1S brushless - Rear motor FPV - Page 4 - RC Groups
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May 16, 2016, 10:54 AM
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basicguy's Avatar
Thanks it is a flat plate airfoil with a split bamboo skewer to act as a leading edge and offer some stiffness. I could have used two layers of foam and had the stiffness but it would have increased drag. I only have 8 watts of power to pull around what ever airframe I choose.

The mother board is from banggood. You would want a 5-10 gram motor with a a KV of 4-5000. the speed controller is a MX3a available from many vendors.

We all have our strengths and things we want to do with modeling. I have made some scale(ish) models and find that in the end they don't really seem to fly better than my imaginary ones. From 50 feet away you can't tell if you have a Ken doll in them or not.

I did fly the plane last night after putting on some shorter control horns to make the plane more responsive and it actually rolls now.
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May 26, 2016, 05:30 PM
Laughs at un-boxing videos...
basicguy's Avatar
My plank #2 had the hinges loosen up not long after I built it. It had 1" strip elevons would pitch on a dime and roll like grandpa.

After flying the elliptical wing planks and the rebuilt Plank #1 which now has 8x2 elevons. I decided to taper the rear of the wing from 9.5" chord to 8" chord at the tip.
I made the ailerons 2x10" while decoupling the elevator function. The elevator is in the center and is 3/4" x10.

The plane actually will roll now pretty rapidly. The elevator was minimally effective. I turned up the end points to 120% too mitigate some of the sluggishness I created on pitch. I am going to rebuild it again with maybe a 2x10 elevator. Hopefully it should be pretty close to ideal.

I kind of get a chuckle out of those who have to create an exact duplicate of a 70 year old plane.

Sorry no video this flight.
May 31, 2016, 10:09 PM
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basicguy's Avatar

Updated Slope plank KFm2


I decided to make my "slope plank" more useful in my field and hopefully keep ok if I ever get to a point of wanting to slope it.

Copy of Powered Slope Plank (1 min 56 sec)


Still has a wing loading of 2.4.
Flying it with a Turnigy c1826 18 gram motor on 2s, 60% throttle most of the flight.
Last edited by basicguy; May 31, 2016 at 10:27 PM.
Jun 05, 2016, 10:10 PM
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basicguy's Avatar

Another smaller one.


Made this one today. Used MPF for this one. A single plate of board.

Straight leading edge with the trailing edge swept forward by 2.5"

The Span is 14"
Powered by an Eflite BL180 that I rewound to 6000kv. to accommodate the single cell battery. The battery is a 300mah.

It is running off of a v911 brick. I wired in an MX3a speed controller.

RC Plank wing, 1S brushless motor. (3 min 2 sec)


Was flying it earlier in the day in wind of 10-20 wind so I added a second vertical stabilizer. Tonight the wind had dropped 7 and it handled much better.
Jun 06, 2016, 05:56 AM
Registered User
flypaper 2's Avatar
Excellent job, excellent.

Gord.
Jun 06, 2016, 08:36 AM
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basicguy's Avatar
Thanks Gord.
Here is a pic of the plane. Still needs bodywork and paint.

I used a split skewer in the leading edge, also used 1/4 skewers as control rods and horns. Per Thmas B. The motor is fit on another skewer. I don't have the stock motor mount.
Jun 06, 2016, 03:51 PM
Build straight - Fly twisty
Whiskers's Avatar
What a great little package it is.

There is a very strong 'plank' theme in that photo
Jun 06, 2016, 07:12 PM
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basicguy's Avatar
Ha, I didn't see it as 5 planks or something. When the local rc club disbanded, one of the officers gave us the warm up stand. It is covered in fuel stains. We have it in the field but also use it for a portable work bench as it is on wheels. My electrics don't seem to need much warm up.

The wind was 20-25 all day so I took a few minutes to get a group love picture. I have very few that are as they first flown.

Jun 11, 2016, 06:11 AM
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basicguy's Avatar
Had a little trouble with my powered slope plank. It lost a propeller whilst flying over our woods. I thought I could glide clear of the trees but didn't.

When salvaged, the 30" wing was cracked so made a new one. This one was cut from a sheet of DTF with the narrow side being the leading edge. A simple KFm2 shape folded over. Single thin spar salvaged. Has a 12" max chord tapering to 8" at the tip. On this one I put on separate controls. 2 ailerons, one elevator and a controllable rudder.

I have been testflying it on a 3oo 2s battery giving a flying weight of 175 grams. I built the battery compartment at the CG and sized to fit the 450-610 3s battery or 800 2s battery.

KFm2 flying plank wing. (3 min 12 sec)


This is my second plank with a separate elevator servo. I like the effect it gives when flying. The rudder is not as sensitive as I would like Probably because of the short movement arm. I don't need it for coordinated turns but though I would like to have it for increased maneuverability
Jun 11, 2016, 08:59 AM
Laughs at un-boxing videos...
basicguy's Avatar
In reviewing the video some things have come to light.
Lots of adverse yaw. I was running only 32% downward deflection on the ailerons. This worked well for the straight winged plane that this plane replaced. I was not using the rudder very much in the video. I am wondering if the ailerons closer to the CG may be affecting this.

I flew the plane after this flight and played around with using the rudder. It was not that effective. I was hoping that I might be able to induce something wild like a flat spin. Since then I have blended the rudder to act with the ailerons and have decreased the aileron differential. Have also increased the rudder deflection and may need to increase the size, extending it further back

I also set up a switch to use the elevator and ailerons in butterfly mode.

Have not explored just setting up the plane to fly with elevons. The beauty of these computerized radios.
Jun 11, 2016, 04:36 PM
Build straight - Fly twisty
Whiskers's Avatar
'Ya turnin' out more planks th'n a saw-mill.

Love it. Very entertaining, and the videos continue to be a pleasure to watch.
Jun 11, 2016, 09:52 PM
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basicguy's Avatar
Thanks Whiskers, Great getting feedback!
Jun 12, 2016, 08:50 PM
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basicguy's Avatar
Since flying this plane I reconfigured it giving me a switch to activate butterfly, ailerons up and elevator down.

I depropped it a bit and put in a 450 3s. got up high and hit the butterfly switch. Wow what a difference. It immediately slowed down and pitched up a bit. I flew it around for a bit at all throttle settings and it flew good except a bunch slower. No chance at tip stall with the ailerons slightly up.

Another issue I worked on was it's tendency for adverse yaw. I had the down aileron as low as 30% with no real abatement. I moved the down aileron to 60% and blended in 40% rudder. Seemed to abate the adverse yaw.

Been in the 90's today Not much fun standing in the sun.
Jul 16, 2016, 07:59 PM
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basicguy's Avatar

Ellipsio gets an upgrade.


I have been flying this plank wing for some time now. It flies beautiful. Launches like an arrow. After a while I thought time for more beans.
Put on an emax 2212 1400kv motor on it. Going from a 24gram to a 51gram powerplant.

I flew it a couple of times on 2s before running a 3s battery. It launches strong at half throttle with a 10x5 narrow blade prop, hardly any torque roll. On 3s, it climbs almost faster than it will dive with the power off. Usually when I'ved up the power significantly bad habits occur. So far none yet.
Sep 15, 2016, 05:33 PM
Registered User
Todd52's Avatar
Hi , I was inspired to try a Plank thanks to Basicguy
I just started the build.Its 36" ws 12" chord at center 11" at tips. Kfm3 steps around 40 and 75 percent.3 channel , ailerons and elevator. Just got the control surfaces hinged .Its a quick build If I like the results I will improve on it.


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