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swappable motor glider

zev

lumpy member
#1
hello my lovely people!

I was thinking about the whole swappable series, would it be possible for you guys to make a motor glider with it? or would it be to unaerodynamic?

just a thought, and I think it would be a fun addition to the series.
 

colorex

Rotor Riot!
Mentor
#2
hello my lovely people!

I was thinking about the whole swappable series, would it be possible for you guys to make a motor glider with it? or would it be to unaerodynamic?

just a thought, and I think it would be a fun addition to the series.
Would need a looong wing, but it could work as long as it has low enough wing loading...
 
#5
Standard Armin wing for 24 inches through the center. Half span di-hedral wingtips (could be straight to whatever level stability you want) half board span tapered at the tips to 60-75% chord. Box fuse and standard tail surface proportions. Woudln't be hard at all.
 

Foam Addict

Squirrel member
#6
A modified guppy might work very well too. I would try to build one, but I used all my foam making 3 das ugly sticks, and a swappable stick. I'll post a build log if I can get the fuse shape right.
Zev, google guppy glider rcgroups, and you should get a wealth of info on it.
 

zev

lumpy member
#7
@colorex: oh… thats not too bad. when you say looong I am thinking like 8ft :p
@MrClean: I am sorry to say it, but all of that (well, I know what an arman wing is, and what dihedral is, but other then that…) went right over my head. could you explain a bit?
@Foam Addict: just looking at that now… cool stuff.
 
#8
Take a foamboard length center section wing which is a rectangle when viewed from above. Now imageine another one half the length BUT instead of the trailing edge being straight so you have another rectangle, bring the trailing edge forward to about 75 percent, perhaps more. See what that looks like from the top? Leave the leading edge straight and when you go to cut the length of the folded over top piece, cut that at an angle to match the trailing edge. Leave the spar section the same thickness, we'll use that for a progressively thicker airfoil. Make two of these, remember one for each side, and decide if your wing will be flat OR if you want poly-hedrahl like the FT Old Fogey has. Put one of the wingtips up to a straight table edge so that it's even with the table, block the narrow tip up to 2 inches and then use the vertical side of the table to sand any overlapping wing vertical with the table. Now you can but the wingtip up to the center section of the wing and it will mate flat with 2 inches of elevation at the tip. Do this for both sides. You can follow the angle made by this and cut a thin plywood doubler to fit against the spars of both pieces to re-inforce the joint and hot glue all that mess together. Now you've got a wing thats flat in the center with wingtips that are 2 inches up. That will give you a bunch of stability and you can fly the glider with rudder, elevator and throttle. If you want to use ailerons, leave the wing flat all the way across OR just add about half an inch at the tips. This will give you less stability but will leave ailerons active. More dihedral less response to ailerons but more response to rudder.

Thats just the wing. Make a tail surface thats 15-20 percent area of the wing with 10 percent of that area elevator surface. Make a Rudder that 10 percent of wing area. Make a fuse to hold these pieces in their appropriate place along with a power assembly, radio, battery and servos and move the pieces around on it till it looks about right and the balance is correct, CG somewhere around the peak of the wing or slightly in front. Mount that stuff permanent with hopefully an area in the battery compartment to move that around with, make it fly.

The Palo Altos club has a website with calculators to figure out the correct proportions for all this stuff. Use mr google to find it and start reading. It'll take a while. One things for sure. If you put something together, go away for a couple days and next time you look at it you say 'Man, that don't look right' it probably isn't. Too many times I see motors about 2 feet away from a wing and tails 5 feet back to balance when a 6 inch nose and a 2 foot tail would do. Not that you couldn't fly one that way, but the farther away the parts are from the center of balance the more of a barbell effeect you will get. Think of holding a barbel with both hands close to the weights. Easy to control right? Now, put your hands together in the center of the bar and try moving the thing around. Wow do those weights have a mind of their own out there at the end of the bar. You don't want that.

Can I cofuse you any more? Want me to keep going?
 

zev

lumpy member
#9
O.O that post is going to be my evening reading for a week.

seriously though, thank you for the time and effort put into that. now i'm gonna try to figure it all out.
 
#10
Make sure and check out the Palo Altos club site. The part you want to look at for design is under the Instructors tab. It's a great resource and explains general aerodynamics past "make it balance here" and "thrust, drag, weight and lift".
 
#11
I'd be interested in what the Flitetest folks can do for a swappable glider.

I've been working on something similar for a while now. Details on my RCGroups blog (http://www.rcgroups.com/forums/member.php?u=362109). I'd be interested in feedback from some glider folk--I've really only been into gliders since I started the project.

I just wanted something small and simple. So much for that--at least I still have small.

Cheers!
Randall
 
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#13
Kids building and flying rc planes is great... I luv it.. Keep it up!!!

The term glider is so general, cause you get gliders that can stay aloft for hours in a thermal, and then you get one's that can only fly at the slope.. Some can be winched, discus launched, or towed, or its own motor..

I cant wait to see what Josh and David gliders are going to be like..

Just a side note, my fastest plane (hanging from the roof) is a gliders , I reached over 200mph, with dynamic soaring (DS)
So the fastest plane build off and swappable glider can be the same plane.. Or not.
 
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#14
I too am looking forward to see a swappable glider from Flitetest guys. Something which will be very relaxing to fly. I have seen one of my friends flying a Parkzone Radian and always envied it :p. They were reviewed by Flitetest in January 2012.
http://www.youtube.com/watch?v=aLuN1T8Waog

Josh and David, please come up with something like the Radian. It will be great! You guys can do it :applause:
 

Craftydan

Hostage Taker of Quads
Moderator
Mentor
#15
I too am looking forward to see a swappable glider from Flitetest guys. Something which will be very relaxing to fly. I have seen one of my friends flying a Parkzone Radian and always envied it :p. They were reviewed by Flitetest in January 2012.
http://www.youtube.com/watch?v=aLuN1T8Waog

Josh and David, please come up with something like the Radian. It will be great! You guys can do it :applause:
Samerkm,

If you're wanting an easy DIY glider, from the podcast (IIRC) FT has one coming, but why wait? Check out the photon:


Build it, fly it, and when FT releases theirs, build one of those too!
 
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#16
Would need a looong wing, but it could work as long as it has low enough wing loading...
actually all you would need would be to make a long wing and add carbon fiber rods to it. they are not that expensive, and very light.

im considering adding a carbon fiber to the spar to my FT racer build