Rubber

[illusionist]

New Albany, sorry for interrupting, but I think my question will help you out too.

So a couple pages back, we were discussing pitches and how they work with 1/8 rubber. Well, I built a new helicopter, and here are the dimensions for the rotors:
-1.2 inches vertical spacing
-2.5 inches tip to tip
This one does better than before, and it can at least get airborne with 1/8 rubber, but it doesn't fly for longer than 20 seconds. It weighs <4.1 grams, and is a conventional dual rotor design. I have no idea for improvements. What can I do to make it fly with 1/8???

[jander14indoor]

New_Albany_Eagle, there is no 'ideal' wind for a 4.0 gm helicopter. It will depend on the pitch of your rotors. This is where the hard work of making these things fly long comes in and there is no broad table matching pitch to rubber. In general, wider/higher pitch rotors will take fatter rubber, less winds but spin slower. Narrower/lower pitch rotors will take skinnier motors and more winds but spin faster. In almost all cases, if you have the ceiling for it, you need to wind your motors to near breaking. Even if you don't have the ceiling you need to wind to near breaking and then back off to the launch condition for the site.

illusionist, that actually seems like a fairly high pitch rotor. With that narrow blade width I wouldn't call it low pitch till you get down below maybe .75 inch spacing. But, some questions. How hard are you winding the motor? See above, you really need to wind these things. Try larger motors and see if you get longer flights. Suggestions and direction only.

Jeff Anderson
Livonia, MI

[illusionist]

With the 3/16, from which I have gotten about 1:30 (with a higher pitch rotor), I am putting in about 500 winds.
On the 1/8 (with the pitch I gave above), I put in around 1100. Even without backing off winds, it still doesn't climb high enough to hit the ceiling. I'll take your suggestion and make the pitch even shallower.
So a question regarding what you said about the narrow width; if I keep the vertical spacing the same, then I would increase the tip width right? That should have the same effect as reducing the vertical spacing, correct?

[lllazar]

Illusionist, your rotors need to be lower pitch. Also, makes sure u reduce friction around the prop shaft because that's what was killing my ability to climb with 1/8 a while ago. With these two things in mind, your copter should easily fly with 1/8.

[Draylon Fogg]

Another thing is, how much wobble do your rotors have? if they are all over the place you might need to re-attach them in a straighter fassion.

[mrsteven]

Another thing is, how much wobble do your rotors have? if they are all over the place you might need to re-attach them in a straighter fassion.

definitely!
I would like to take this oppertunity and tell the world: dont EVER double over 1/8 rubber and put 400 winds on it... = broken helicopter.

In terms of lubricant on the rubber, I'm hearing alot of people are using armor-all. When I went to the store I found 5 kinds of armor-all which is the one you guys are using? I picked up the general 'orgional protectant'

[Draylon Fogg]

ive never used it but i was watching a team, SJA, use it an the broke like 12 bands before they could finally get one to fly. but ive also seen some people use it and it do just fine, its just another one of the possibilities for a lubricant.

[jander14indoor]

<SNIP>So a question regarding what you said about the narrow width; if I keep the vertical spacing the same, then I would increase the tip width right? That should have the same effect as reducing the vertical spacing, correct?

Increasing width, decreasing spacing decreases pitch.
Increasing spacing, decreasing width increase pitch.
Note, though. These things aren't entirely independent. Increasing or decreasing width changes the blade area. Something we haven't talked about much, but certainly relevant in the lift and drag equations.
Changing spacing within reason doesn't affect area much.

<SNIP>In terms of lubricant on the rubber, I'm hearing alot of people are using armor-all. When I went to the store I found 5 kinds of armor-all which is the one you guys are using? I picked up the general 'orgional protectant'

Yeah the basic general or original stuff is fine. Used by long time rubber flyers, lots of experience. Won't hurt your rubber. Actually doesn't take a lot to do the job. Bath them in it if you want, but don't worry about wiping of most of it to get rid of the weight before you fly.

Jeff Anderson
Livonia, MI

[mrsteven]

<SNIP>In terms of lubricant on the rubber, I'm hearing alot of people are using armor-all. When I went to the store I found 5 kinds of armor-all which is the one you guys are using? I picked up the general 'orgional protectant'

Yeah the basic general or original stuff is fine. Used by long time rubber flyers, lots of experience. Won't hurt your rubber. Actually doesn't take a lot to do the job. Bath them in it if you want, but don't worry about wiping of most of it to get rid of the weight before you fly.

Jeff Anderson
Livonia, MI[/quote]

so would you say to spray/bathe it immediately before you fly or soak a day before or so?

[Draylon Fogg]

do it right before you fly