Removable Wing on Profile Fuse?

[Seared Ice]

I'm working on making a scratch-built profile 3d plane and I want to have the wing removable somehow. I know this option isn't popular and I figure there must be a reason why... Even so, I'd like to try...if it doesn't work I can just glue it in permanently...
Does anyone have a profile kit/arf that they've built (or not) that has a removable wing? What keeps the wing stuck to the fuse...rubber bands/nylon bolts/etc and how? A picture perhaps?
Has anyone built a profile plane of their own with removable wings? How/what? Picture perhaps?
I've seen one plane with removable 2-peice wings...I might want to do this but I think a removable 1-peice wing would be easier.

I'm thinking I could have a ply or balsa "tongue" come out near the LE and TE of the wing (glued to the fuse) on one or both sides of the fuse and then use nylon bolts into the wing to hold the wing in place. The other idea I had was to have a peg at the front of the wing go into a place in the fuse that's like double or triple thickness (to be strong where the peg fits in) and then have a balsa or ply tongue as mentioned above at the LE with nylon bolts. I attached a render of a quick 3d model I made to show what I mean. Left is my first idea...right is my second. In the right one, I didn't include the fuse so the peg would show...the tongues in back would be glued to the fuse at the center. Sorry for the cheap 3d comp. models...mine in real life will look better! ;)

What do you guys think of my two ideas? Will they work? This model will only come out to a few ounces so I don't need anything to be strong enough for a glow engine...I'm going electric...and small electric...

~John

[capncrunch]

The only profile wing attachment system I've seen is wings with plug-in tubes. do some searching and you might see what I mean. there's one in the profile forum, I think.

the problem with keeping the wing in one piece is that you will probably not be able to simply slide it through the fuse and into place. remember that there will be a servo linkage hanging off the bottom (or top) of each wing half, and that wouldnt normally fit through the wing cutout in the fuse.

Is this a balsa plane? a foamie? If you arent going to have linkages in the way, you might be able to get away with a solid wing. on the other hand, if its too small to bear the weight increase from making the wings removable, perhaps the wings arent big enough to need to be removable.

-barrett

[Seared Ice]

Yeah...they don't NEED to be removable...but I like that option on a plane.

I thought about the linkages. For weight reasons (lol) I'm using 1 aileron servo on the fuse so it would be as simple as disconnecting one pushrod from the horn to get the wing in place.

I'll search around some more. I think I'll just try something with making it removable but I bet I'll just end up making it permanent...

I'm starting to go crazy, waiting for the balsa to arrive in the mail!
~John

[capncrunch]

another option would be to make the section of fuse below the wing part of the wing. In this way, the wing slides up into the fuse rather than through it. this is typical in mid-wing planes with a one piece wing. the downside is that it can weaken the fuse, since you now have only the top section of the fuse bearing all the tension/torsional loads. I should qualify that by saying that you lose more strength when you go with a peg in the front and bolts in the rear of the wing. if you can design a way to use bolts on the front and back, you'd regain some of that strength.

would it work to have like a tongue extending fore and aft of the fuse below wing that would fit into grooves on the fuse? then you could thread a short 1/4-20 nylon bolt through a hole in all three. it could even be part of a landing gear mount assembly...

make sense?

-barrett

[Seared Ice]

yeah, I thought about having the lower part of the fuse removable but that, I think, is too much for a small profile like this.

I don't really understand your second idea but i think i understand it a bit. I'll make a 3d computer model of what i am getting from what you said...

just a few more minutes 'till i'm done...then i'll post the render.
~john

[Seared Ice]

Whatever...I can't figure it out lol! Does your idea have a 2-peice wing? If so, i think i get it. If not, please explain some more :) I think i could use some more explaination even if it is 2-peice lol.
~john

[capncrunch]

here's a quick cad model of what i meant, its a wireframe of a fuse and a wing center section/lower fuse.

there are tabs on the center section that fit into grooves on the fuse. a bolt or two through this sandwich on the front and the back could be a pretty strong attachment. of course, side loads are something to worry about, too.

-barrett

[Seared Ice]

Cool. Now I get it :P I had a somewhat similar picture of what you're talking about but the tabs were in a different place.

I'll look over my plans (and maybe make a couple alternative versions) to see if the way I'm trying to build mine will work with your idea (have to make sure there's enough structure at the skinny part fore and above the LE).

~John

[capncrunch]

the other thing you have to think about any time you design a removable section is how you are going to connect any servos or linkages that cross the boundary.

so, with this type of thing, with a single servo, you could put the servo in the wing and use a servo wire extension to connect it to the rx in the fuse. if you put the rx in the wing, you'd have 3 connections to make -> more wires -> more complexity and weight.

or, you could put the servo on the fuse and connect/disconnect the linkage when you remove the wing.

a small plane like this with a removable wing could be a great vacation flyer, like a "suitcase plane"... just another idea for you to think about as you work on the design.

[Seared Ice]

Yeah...vacation flier :) I already have my IFO which fits in a suitcase :) Perhaps I'll make the stab removable too on this plane...but not too easily cause I don't go on vacations often ;)

~John

[Seared Ice]

I like your idea for mounting a removable wing. It doesn't seem it will take much strength from the airframe...there's only really the 1 stick that runs the length of the bottom of the fuse that will be compromised for the removable wing...And the tab areas will probably make up for that...

The picture is of the plans from before any changes. I will make another post in a bit with the altered plans...

~John

[Seared Ice]

I might not make it a 3-layer attachment like you described...maybe just two. What diameter nylon bolts would I want to use?

Here's the proposed changes:

[TheAeronut]

Very good design there. I would put some sort of tab or key on top of the wing on, or just ahead of the spar to help take torque and rolling loads. A three point connection is quite rigid, and the more widely spread the three points are, the more easily they can dissipate any loads placed on them. Perhaps you could just put a couple of tabs on top of the wing that slide up over either side of the fuselage.

As far as bolt sizes go, if you add the tab on top, I would guess that nylon bolts sized about 8-32 should be adequate for mounting a wing in a plane up to around 24 ounces or so. 10-32 should do up to about 32 to 40 oz, and 1/4-20 for anything less than monster size.

J.P.

[Seared Ice]

Good point!
And thanks for the info on the bolts...I'll check to see what the hobby store has. I'm hoping this plane will come out to less than 24 ounces ;) Less than 10 would be nice ;) lol
Breakfast time now,
John

[capncrunch]

Hey john,

is there a big hardware store in Media or thereabouts, with a small parts section? Most medium to large Ace hardware stores will have one. its a great way to basically find anything you need for nuts/bolts/washers from 4-40 on up standard and 2mm and up for metric.

basically, you pay by the piece, you'll find a wider selection, and you'll save $$ over prepacked dubro parts.

it's like boat supplies... most things that say "marine" on them can be found at a regular hardware store for 20% less :)

J.P. makes a very good point about adding a third tab.

-barrett

[Seared Ice]

Yeah, capncrunch...Home Depot and Lowes and probably an Ace too. I'll be passing a Home Depot later today so maybe I'll stop in to see. I know they have tons upon tons of metal hardware but I've never looked to see if they have nylon parts. Thanks for pointing that out. Even if I can't find anything in Home Depot, I'll be passing the LHS on the way home from there!! I could even check in the arts/crafts store...I'll be stopping in to see if they have some balsa.
~John

[Seared Ice]

:) I don't have anythign to say but I got a warning that 1 smiley isn't a long enough post lol!