Quad Tilt Rotor - Build Log (Comments & Suggestions Welcome) - RC Groups
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Dec 07, 2007, 05:24 PM
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maxvtol's Avatar
Build Log

Quad Tilt Rotor - Build Log (Comments & Suggestions Welcome)

I guess it's time to start my log. I don't think building a plane from the outside in is such a good idea on your first plane (if I had to do it over again, I think I would go balsa). I think I'm far enough along where the time between posts shouldn't be too long, and progress reports can come more quickly.

The main reason I'm going fiberglass is that, as far as I know, transitioning with a custom mixer has never been done before, and if my bird decides it wants to become a terrestrial submarine, hopefully I can get flying again faster by pulling a new part from a mold. We'll see.

I could probably spend another several days detailing the drawings in Solidworks, but I think it's at a point where building will be as quick as drawing.

From here I'll probably start on the fuselage and make some drawings and a jig of sorts to locate the parts.

From the test part and samples I believe the model will come in at 10lbs + or - .5 lbs, hopefully I can keep it on the lighter end.
Last edited by maxvtol; Dec 07, 2007 at 05:30 PM.
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Dec 07, 2007, 06:04 PM
Sussex, UK
RobinBennett's Avatar
Wow, that plug looks gorgeous!

You forgot the other potential benefit of building a composite model - you might be able to sell wings and fuselages to others who don't want the hassle of building the mould :-)
Dec 07, 2007, 08:59 PM
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maxvtol's Avatar
Thanks Robin, yes that has crossed my mind. Building a mold is definately more difficult and expensive than I thought it was going to be.
Dec 07, 2007, 10:33 PM
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v22chap's Avatar
Man Max ,,you can do it all ,, I just don't have the time to learn how to do composite or glass molds ... maybe some day ..
Looks really , really great and I think you are right about the mold pulling ...it takes for ever to do a balsa build
Dec 08, 2007, 03:29 AM
1.21 gigawatts
Max impressive work ,,
are the nacelle servos geared down or direct
Dec 08, 2007, 08:36 AM
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maxvtol's Avatar
Thanks V, I don't know that I have mastered the composites, still a lot of trial and error, but hopefully once I get it figured out, replacement parts or new parts will come more quickly.

Eddie the motors are direct outrunners, same as I used on my test rig. They're Electrifly Rimfire 35-48-850 and have no trouble turning the 16x10 thin electric blades with 11.1v lipos. They're rated at 666 watts constant output, not bad for a 6 oz motor.
Dec 08, 2007, 09:43 AM
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Absolutely fantastic Max looking forward to getting updates on the build.

What did you make the actual plug out of in the first place, how did you get that gorgeous shape?

Best of luck and remember - lots of pictures!
Dec 08, 2007, 09:49 AM
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joeling's Avatar
Hi maxvtol,

Very cool. Wish u the best in all u do ! Please do keep us updated.

Joe Ling
Dec 08, 2007, 09:57 AM
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maxvtol's Avatar
Thanks Ken,

I made the shape in Solidworrks, generated CNC g-code in Visual Mill, then took it to a friends sign shop and cut it out of 20lb sign foam. Then epoxy and sanding, then paint and sanding, then sanding and sanding, then sanding and sanding. Then wa- la, 4 months later I had a usable plug, which was damaged once I pulled it out of the mold. The parts that come out though, look pretty good though.

I'm going to keep the pics coming, but try to just post the stuff that works since I'm still learning.

BTW, how do you align your hinges on the ailerons when putting them in, and do you put them in the control surface or wing first? My ailerons are 8" long so I think I'll need 3 hinges.

Thanks Joe Ling
Dec 08, 2007, 01:53 PM
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Lucky you having the CNC capability! Must have been brilliant to see the shape come to life, I keep meaning to ditch AutoCAD and migrate to Solidworks but the cost is just to high for home hobby use over here, AutoCAD isnt a patch for generating 3D stuff.

I use Robart hinge pins, which you have probably seen, They are easy to use simply drilling a 2mm hole in the hinge itself and the wing mating control surface. Just mark the centre line on the face of the control surface and on the aileron itself. Measure in both sides of the aileron an equal distance then drill the holes, place the hinges in and crank the free end 90' and square up. I then offer the aileron in position and mark the position of the hinges on the control surface. Drill and see how you got on.

If you are slightly out file the offending hole slightly until you get everything square. Put a small amount of WD40 or other lubricant on the hinge pin, mix up some epoxy, place carefully in the hole drilled and place the aileron in position, tape in place until set. The slight enlargement of the holes wont matter as the epoxy will take care of it. I put lubricant on the hinges in case I get some epoxy on them by accident!

Note that with this type of hinge you have to get the centre line of the hinge pin itself quite deep into the aileron to prevent binding, do lots of trial fitting before glueing

Hope this helps
Dec 08, 2007, 02:31 PM
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v22chap's Avatar
Wooow ... If I am reading you right Ken I do my flapperons the same on the V ,, only my flapperons are 21 " long ...and really deep ..so I use Robarts super hinge that has the 5 mm size mount barbs and I use 4 of them per side recessing them into the aileron about 3/8 " (edge of ail to CL of pivot pin .I too use the oil in the hinges just in case (been there done that and had to remove one )

I then add a 1/2" flap to the top wing skin to cover the offending holes in the front of the ail when it is completely 78 degrees down ,,this is also kind of what the real one does ..only there's is a cam controlled one that extends some as it follows the flapperons.
Here are a few sneak pix of 08 "V" to show you what I mean ,,,,never mind the sloppy covering job as I am trying to get it hovering and don't really care what it looks like as the life expectancy of this bird is very marginal
Dec 08, 2007, 02:49 PM
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maxvtol's Avatar
Thanks Ken and V, I think I understand now.

Have some video of a 40th scale fuselage plug for a test I did. I didn't video the 10th scale plug, I think it took about 6+ hours or so for both halves.
CNC video of 40th scale fuselage plug

And V, wow how big is that V-22 going to be? Your flap is about the width of my front wing.
Dec 08, 2007, 03:02 PM
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rctiltwing's Avatar
Looks great.
Why do the props point inward when vertical, and how much lift do you expect to lose due to this? I think the V-22 has a slight tilt (camber?) in the other direction (outward), but the reason escapes me at the moment.
Like Eddie IŽd also like to know whether the tilt servos are geared and if you have tried them out with the motors at full speed.
Dec 08, 2007, 03:14 PM
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v22chap's Avatar
My V has a wingspan of 51 " and nose to tail of 68 " same as all the others I have done and the one in the video ... I am old and have to have them big to see ,,, I also found ( long time ago and it might be different now with batteries and motors being better ) that to carry the weight I do it seems to have to be 1/10 size to get the power to weight ratio right . This one is the first electric one and things may change alot after this one.
Joe and I envision a Trex based one in the future.

rctiltwing ..yes the real V has outboard tilt in heli mode of about 3 degrees and if I remember right it is kind of like dihedral on the wing ... I have 2 degrees of swash plate out ward tilt and it seems to make it more stable in the heli mode and so far hasn't hurt the forward flight to 60 degrees .
Max ,,does this Joe do jobs for any little guy like that ??? and about what did it cost ???

Dec 08, 2007, 03:38 PM
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maxvtol's Avatar
RC, they tilt in for a little more stability. I'm using gyroscopic forces and torque to help with the pitch and roll control in hover. They tilt in at 12 degrees so in theory they should loose less than 3%, though I haven't tested that. In cruise they're straight, so there isn't any loss of thrust there.

I didn't read Eddie's post clearly, sorry, the tilt servos are direct and are Hitec robot servos . If you've seen my BEC failure post, you'll need to use batteries on these servos, BEC's can't handle them.

Larry, very cool, can't wait to see more of your build.

I'm Joe, but I kinda like being called Max (my middle name). Call me whatever you want, I'll answer. Yes, I can try to do something for anybody. I think by the time you figure foam and machine time I was a little over $500. The foam does need to be finished with epoxy or something to give it a smooth surface, it can be quite time consuming to get it smooth, but you'll have an accurate shape.

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