Cubchel

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TLAR

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Sep 29, 2020
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224
Does anyone know how the Cubchel wing rotating mechanism works?
I understand the whole wing pivots incidence wise which introduces roll. No ailerons.
I would like to see how the spar root pivots.
Pilot reports?
 

dominique

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Aug 17, 2015
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34
Location
france
Hi
Clubchel and Demoichelle are very similar
I think it is the same mechanism
You can find photos here
Dominique
 

TLAR

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Sep 29, 2020
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224
Thanks Dominique, exactly what I was looking for
 

Protech Racing

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Jul 10, 2020
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I would like to do that also but my first priority was folding wings. In my case from the rear spare .
How much angle do you think you need for proper roll control?
 

dominique

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Aug 17, 2015
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france
In the second text
Le profil choisi est le NACA 23112. L'angle de débattement différentiel des ailes est limité par butées à +2° et -4°
The airfoil is the NACA 23112. The differential travel angle of the wings is limited by stops to + 2 ° and -4 °
Dominique
 

addicted2climbing

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Since your in France reach out to the APEV group for more info. If your going to do it on the plane in your website than you will neef an an anti drag wire and rear support wire going to the strut for if to work. Remember the. Wing is only attached at one point so the strut needs to be secured gore and aft. Also all the Apev planes use a special airfoil that works well as a moveable surface and pivot point location is critical.
On another note where in France are you. I have family in the GERS.
 

rtfm

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Brisbane, Australia
Also all the Apev planes use a special airfoil that works well as a moveable surface and pivot point location is critical.
Could you elaborate on both points? Which airfoil? And why is the pivot point so critical? Mignet used a rather weird airfoil, and placed his spar at it's thickest point, which was also where he attached his pivot point. Happened to be at about 22% chord. So his CP was a few percent behind the pivot. In his paper, he says that the pivot point is "about 5cm ahead of the CP" leading to a pull on the stick as the wing starts to produce lift. Over the ensuing years, it has become usual to use the NACA23102 or NACA23112, with the spar at 25% chord without much standardisation about where to place the pivot point. It has to be ahead of the CP, that's clear, but by how much is an open question. Depends on how much tug one wants from the wing I guess...

Duncan
 

addicted2climbing

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Could you elaborate on both points? Which airfoil? And why is the pivot point so critical? Mignet used a rather weird airfoil, and placed his spar at it's thickest point, which was also where he attached his pivot point. Happened to be at about 22% chord. So his CP was a few percent behind the pivot. In his paper, he says that the pivot point is "about 5cm ahead of the CP" leading to a pull on the stick as the wing starts to produce lift. Over the ensuing years, it has become usual to use the NACA23102 or NACA23112, with the spar at 25% chord without much standardisation about where to place the pivot point. It has to be ahead of the CP, that's clear, but by how much is an open question. Depends on how much tug one wants from the wing I guess...

Duncan
Hello Duncan,

You can read about it on the APEV website. If I remember correctly the pivot is near the center of lift to help with some of the stick forces. Also the airfoil used was tweaked to work as an all flying surface and not traditional with a moveable surface. I only mentioned it to the OP so he did not think he could take his existing airframe with whatever current airfoil is on it and just make the wing pivot. I wanted him to be cognizant of the nuances with doing this and the info was out there, but he liekly woudl need to make changes to his wing and strut design.

On another note I have the Demoichelle about 60% in Solidworks and I hope to make one some day. Downside is getting the 100 x 50mm x 2 mm spar extrusion is impossible here. I redesigned my wing for 4" x 2" but I can only find .125 wall thickness which is a bit more than 1mm over standard so its a 50% increase in weight for no good reason. If I could find .094" that woudl be closer. I have an extrusion vendor I use all the time, but if they know its for an airplane as a structural part they will No Bid it. I am sure I will sort this out one day.
 

TLAR

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Sep 29, 2020
Messages
224
As usual, I always pick a design that can’t be built. The EMG6 has wing rib attach fittings that have to be machined. NoGo.
The Cubchel has an metric wing spar. I can get close to the correct size but, that don’t get it. Close only counts for Horseshoes and Hand Grenades.
So, that leaves a fabricated spar. The four angles would increase the weight, but would no doubt be as strong.
I will order the plans this weekend and look it over.
I will make this statement though, when a composite guy looks at the airframe, it is a very good candidate for the Carbon Fiber treatment. All straight fiber path. Extremely Rigid.
We shall see😁
 

Protech Racing

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Jul 10, 2020
Messages
413
Hello Duncan,

You can read about it on the APEV website. If I remember correctly the pivot is near the center of lift to help with some of the stick forces. Also the airfoil used was tweaked to work as an all flying surface and not traditional with a moveable surface. I only mentioned it to the OP so he did not think he could take his existing airframe with whatever current airfoil is on it and just make the wing pivot. I wanted him to be cognizant of the nuances with doing this and the info was out there, but he liekly woudl need to make changes to his wing and strut design.

On another note I have the Demoichelle about 60% in Solidworks and I hope to make one some day. Downside is getting the 100 x 50mm x 2 mm spar extrusion is impossible here. I redesigned my wing for 4" x 2" but I can only find .125 wall thickness which is a bit more than 1mm over standard so its a 50% increase in weight for no good reason. If I could find .094" that woudl be closer. I have an extrusion vendor I use all the time, but if they know its for an airplane as a structural part they will No Bid it. I am sure I will sort this out one day.
Look at the 2x5 Pool enclosed rectangle tubing. 055 wall and made my stress test . Check it out, might work for you.
 

TLAR

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Sep 29, 2020
Messages
224
Where did you find that tube? In Oz, they outlawed aluminum tube that does not have a radius on the inside corners.
 

addicted2climbing

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Look at the 2x5 Pool enclosed rectangle tubing. 055 wall and made my stress test . Check it out, might work for you.
I don't think the wing thickness can support a 5" vertical section. Daniel will sell the tubes needed to USA builders, but its a bit of a pain since they are 4 meters long each and you need 3 or 4 per plane as the body also uses them as well. I tried to coordinate with him for a container already heading this way to put say 20ea inside so local builders would have access to them, but the person shipping the plane to the USA ended up not doing it.

I hope to one day try again, but I am a bit swamped at the moment with other things. 2" x 4" x .13" will be fine if your not too concerned with the added weight but if your trying to hit Part 103 it kills it for sure.

Marc
 
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