Rotors

[lakersfan2012]

I have been using the parlor copter design for the past year or so, and we've been doing fine (placed at state last year, max time around one minute). We've been tweaking it slightly to try to improve the time, but the results have not been dramatically better. We are now looking at a design overhaul. Any ideas for rotor improvements? (We have tried a helical screw design, which did not produce any better results)

[jander14indoor]

Okay, so would ANYONE be willing to help me? None of us understand how to build a functional helicopter... I built one, but when I released it, it went up and slowly went down in about 5 seconds... I need help BADLY! Our competition is the 26th of February, and we haven't even constructed a functional helicopter, let alone our competition model! Our team has always won, and I don't want to be the one to mess it up... Any help I receive would be greatly appreciated! First of all, what shape should we use for the rotors. Are we allowed to use kits. I'm in Division B at North Carolina, so our rules are different, but could someone read the rules in this link and tell me if you think using an entire kits is legal? I think so, but my coah disagrees... Thanks a lot!!! Hope to hear back really soon!

RULES (PDF): http://www.sciencenc.com/event-help/rul ... rs11BC.pdf

This site is ALL about helping folks. BUT, you need to do some basic research first. Spend some time looking through this topic, much detailed help already offered, make sure you understand it or ask specific questions. Also, the NC web resource for this event has some wonderful hints and tips, see http://www.sciencenc.com/event-help/helicopters.php

Now, what we need to know to help. What kind of helicopter did you build? How much did it weigh. What kind of rubber did you use? How many winds? How much rubber? DETAILS!! With that we have a chance of helping, without it, we are shooting in the dark. PS, sounds like you have a functional helicopter from your brief description, but what you need is better performance. With details we can tell if only small changes are needed for better flights, or a complete restart is in order.

I have been using the parlor copter design for the past year or so, and we've been doing fine (placed at state last year, max time around one minute). We've been tweaking it slightly to try to improve the time, but the results have not been dramatically better. We are now looking at a design overhaul. Any ideas for rotor improvements? (We have tried a helical screw design, which did not produce any better results)

The parlor copter uses helical screw design!! Anyway, I don't have the parlor copter plans, what's the rotor size? Final weight? Rubber weight? Again, details of what you've tried so far.

Thanks,

Jeff Anderson
Livonia, MI

[smartkid222]

Or you could get a 0.021 wire drill and drill out the PP bearing to fit your .020 music wire.

Where can you get drill bits so small?

[chalker7]

While they aren't the only source, Small Parts (http://www.smallparts.com/) is almost certainly the most comprehensive online store for obscure construction tools and materials like this. They have quite a selection of 0.021" bits http://www.smallparts.com/s?keywords=&p ... &x=0&y=960

[jander14indoor]

Many hobby shops also carry wire drills. Tool supply places. Some hardware stores. There's generally a Grainger somewhere near by and they carry drills that size. Also Mcmaster-Carr or Enco. Also Micro-Mark. All have on-line presence.

Drills that size are labeled by wire size, a #75 is 0.021 in diameter.

Jeff Anderson
Livonia, MI

[Draylon Fogg]

How do you decrease rotor wobble? It flys great but the top rotor wobbles quite a bit and im thinking that it is affecting the time.

[jander14indoor]

Balance the rotors, minimize any space between the rotor axes. Note, that's not minimize the space between the rotors, but between their axes. Assuming you have the typical two rotor copter, one on top the other, the axes should be along the same line as much as possible.

Balance, look up balancing propellors to get ideas for this. Also see other thread in this group on how to build balanced as much as you can.

Jeff Anderson
Livonia, MI

[illusionist]

If I was using a solid motor stick design,and both rotors are on the same axis, but not directly above and below the motor stick. Wouldn't this also cause some unbalance as the motor stick spins around (it's a two rotor, counter-rotating design)? Is there any way to offset this, or is it not that big of a deal?

[WCarneyJX]

3291|68/stevensheli2b.jpg

Mine has a similar set up and it causes no problems at all. Note that both my rotors rotate free of the motor stick so there might be less effect since the motor stick rotates very little.

[WCarneyJX]

How do you decrease rotor wobble? It flys great but the top rotor wobbles quite a bit and im thinking that it is affecting the time.

I've seen some Helicopters that wobble due to motor stick flexing. Does yours?