Rotors

[illusionist]

Just rereading that, Mr. Anderson said through the spar. Do you mean poke a hole right in the middle of a 1/16 spar?

[mrsteven]

Just rereading that, Mr. Anderson said through the spar. Do you mean poke a hole right in the middle of a 1/16 spar?

indeed. be careful

Although when you glue it in, if the wood cracks youll be fine. CA will hold that strong

[chalker7]

Just rereading that, Mr. Anderson said through the spar. Do you mean poke a hole right in the middle of a 1/16 spar?

indeed. be careful

Although when you glue it in, if the wood cracks youll be fine. CA will hold that strong

I actually prefer piercing a larger, shorter stick, (1/8" square x 1") and then attaching it to the spar. This way you don't have to worry about breaking the spar and can replace the motor hook or rotors if need be. I just posted a picture to the wiki showing the technique, so once it gets validated you'll be able to see clearly what I'm describing.

[jander14indoor]

I actually use that method. Here's a picture that I uploaded last year of one of my shafts- http://gallery.scioly.org/details.php?image_id=3443

That would be the spar that is furthest from the bearing. The shaft is glued next to the one that is closes to the bearing. The issue is that the shaft becomes free from the spar closes to the bearing and so the rotor collapses. It doesn't break, but rather flattens.

You need a rib or post between your two spars.

Jeff Anderson
Livonia, MI

[illusionist]

I'll try out the method on the current helicopter I'm building.

On a different topic, what's the best way to attach the ribs in between spars? Currently I put the spars on my jig and cut ribs (angled on the ends where they meet the spars) to fit on top rather than in between them. Could I gain something by putting them in between so that they are flush with the surface of the rotor?

[jander14indoor]

It would PROBABLY improve the air flow to fit them flush between the spars. Lower drag > more efficient. As to how to cut them it should be possible to rig up a jig, but these are compound cuts. Hmmm, have to think on that. Anyway, right now I cut, try fit, cuss, cut, try fit, cry, I get there.

Jeff Anderson
Livonia, MI

[thedoctor]

To cut my ribs so that they lie flush between the rotors, I normally just take a piece bigger than the rib size i will actually need (bigger in length) and let the ends overlap the spars. I then take one of those nice straight edge (long chisel) blades and line it up flush with the lower spar. Then, keeping the blade at the same angle as it was before, I cut the rib; that way, it should be at the correct angle. I then glue this correct end at the right angle and cut the rib end for the upper spar in the same way. I use something like those blocky Pentel erasers to provide support for the rib while i cut it. If you do this correctly and don't do dumb things like gluing the bottom end of the rib so the rib isn't lying against the spar anymore, you should get ribs with ends that match pretty dang close the angles of the spars and thus lie flush between them well. There are probably more precise ways of doing this than the way I do it (I hope you could understand all that mess), but that's how I've been doing it, and it gets good results. Just be warned that it gets much harder to cut ribs this way the closer you get to the center of your rotor because the angles become so steep.

[illusionist]

Thanks, and another thing.
I believe this was brought up in last year's thread, but never received an answer-
Is there a way to mount the "fixed" rotor onto the motor stick temporarily so that you can swap it out for a rotor with a different pitch during testing? I was thinking about maybe creating some notches and tying it on with thread, but it seems very weak.

[thedoctor]

Thanks, and another thing.
I believe this was brought up in last year's thread, but never received an answer-
Is there a way to mount the "fixed" rotor onto the motor stick temporarily so that you can swap it out for a rotor with a different pitch during testing? I was thinking about maybe creating some notches and tying it on with thread, but it seems very weak.

Well I've never done that because I've never tested anything to that extent, but I guess if you make the fixed rotor fit into the motor stick like 3D puzzle pieces that might work...or you could just attach them with ambroid cement and use acetone when you want to take the rotor off, but that might damage the motor stick after a while. As of right now, that's all I can think of...

[chalker7]

Thanks, and another thing.
I believe this was brought up in last year's thread, but never received an answer-
Is there a way to mount the "fixed" rotor onto the motor stick temporarily so that you can swap it out for a rotor with a different pitch during testing? I was thinking about maybe creating some notches and tying it on with thread, but it seems very weak.

Sure, if you made a couple large paper tubes like you might use in Wright Stuff you can make rotors that plug in and out.