Rubber

[lllazar]

Any kind works fine, graphite powder works well for me.

[illusionist]

Are you guys double-looping the 1/8? My helicopter weighs 4.3 grams (I know, i'm trying to lose weight), and it works great with 4 strands of 3/32 or one loop of 3/16. However it doesn't even climb with a 2 gram loop of 1/8...

[thewinner]

That's weird. I am not double looping the 1/8, but it flies just fine. Make sure the knot does not get caught on the motor stick, and make sure the motor stick is long enough. Sometimes with a short motor stick the rubber bunches up and gets stuck. Also, try to minimize friction between the rotors and the bearings.

[chia]

Huh... I've never used lubricant around the bearing before.

[lllazar]

Are you guys double-looping the 1/8? My helicopter weighs 4.3 grams (I know, i'm trying to lose weight), and it works great with 4 strands of 3/32 or one loop of 3/16. However it doesn't even climb with a 2 gram loop of 1/8...

Longer Motor stick (40 cm) and definitely reducing friction between rotor and prop hanger should help. I was having the same problem and i totally re-did my design so that friction was at an absolute minimum.

[illusionist]

Are you guys double-looping the 1/8? My helicopter weighs 4.3 grams (I know, i'm trying to lose weight), and it works great with 4 strands of 3/32 or one loop of 3/16. However it doesn't even climb with a 2 gram loop of 1/8...

Longer Motor stick (40 cm) and definitely reducing friction between rotor and prop hanger should help. I was having the same problem and i totally re-did my design so that friction was at an absolute minimum.

40cm?? Wow, mines only 28cm. What size balsa are you using for the motor stick. I would think that you need some pretty thick stuff for a motor stick that long...
As for friction, I am using 2 plastic beads on the prop shaft.

[chia]

Are you guys double-looping the 1/8? My helicopter weighs 4.3 grams (I know, i'm trying to lose weight), and it works great with 4 strands of 3/32 or one loop of 3/16. However it doesn't even climb with a 2 gram loop of 1/8...

Longer Motor stick (40 cm) and definitely reducing friction between rotor and prop hanger should help. I was having the same problem and i totally re-did my design so that friction was at an absolute minimum.

Is a motor stick that long actually necessary? Mine have been along the lines of a foot long, like illusionist's. A 40 cm motor stick would mean that 2 grams of 1/8 rubber is stretched out a bit even before winding (though dunno how that affects winds or anything).
Either way, maybe because of the pitch you used for your rotors - or friction between rotor and hanger, as lllazar suggested - anything less than really thick rubber simply won't be enough to get it to climb. I had a similar problem with I think both of my helicopters, just not to that extent.

[lllazar]

It's hard to get it to climb often with 1/8. I'm actually thinking of changing rubber, but i've been consistently improving closer to 2 min lately so i think ill stay with 1/8.

And Chia, i dunno if it's just me, but i had a foot long motor stick for a while, but my copter was really wobbly. So i just lengthened it to 40 cm and surprisingly it did have a lot better balance (with all other variables the same). Also, it seems to climb better with the longer motor stick, maybe it's because the rubber is at a longer stretched length throughout the flight?

And typically, i get in around 850 winds regardless of the length of the motor stick. Just be careful with the strength of the motor stick at that length though. You may have to invest 2 g total for the attachments and motor stick combined (pretty much everything excluding rotors).

[illusionist]

How well would Vaseline work as lubricant? (the clear petroleum jelly kinda stuff) I don't have any other kind of lubricant...

[Frogger4907]

How well would Vaseline work as lubricant? (the clear petroleum jelly kinda stuff) I don't have any other kind of lubricant...

It could work, but I think a liquid would work better. Just go to walmart with 5 bucks and grab a spray bottle of Armor All.