Helicopter Testing

[mrsteven]

Quick question guys, i'm new at this any my copter keeps turning on its side and moving then like a wright stuff airplane (obviously not in circles though). What causes this? Is it that the copter is top heavy or what?

Definitely top heavy- either add more weight to the bottom or take some off of the top.
My recommendation is to plan on building it under weight so that you have extra weight to play with at the bottom for balancing and so that the bottom is noticeably more weighty than the upper portion.

I've always done this and never had it flip or turn on its side. Smooth upwards motion

[thsom]

Alright thanks! My copter isn't excessively heavy, it weighs under 3.5 grams actually and all i have to add is the balsa disc to the top and then obviously a counterweight. 2 things. 1. What are some suggested counterweights, clay, balsa, bass, other wood, what else? 2. Where do you get balsa discs? I don't want to waste money and buy a full sheet of balsa if I only need enough to cover a dime. Or are there any other alternatives other than buying sheets?

[mrsteven]

Alright thanks! My copter isn't excessively heavy, it weighs under 3.5 grams actually and all i have to add is the balsa disc to the top and then obviously a counterweight. 2 things. 1. What are some suggested counterweights, clay, balsa, bass, other wood, what else? 2. Where do you get balsa discs? I don't want to waste money and buy a full sheet of balsa if I only need enough to cover a dime. Or are there any other alternatives other than buying sheets?

For 'counter weights' I use a modeling clay that never fully dries so I can take some off or add some easily.
Wood disks I go to a hobby shop in my area and they have balsa galore so they have 1 foot 1/64 by 2 in balsa (not really sticks) but sticks and i trace a coin and make it. So mine are very thin, only really to be accepted by the rule

[thsom]

but aren't you afraid that the disc may fall of or break if it is so thin?

[thedoctor]

but aren't you afraid that the disc may fall of or break if it is so thin?

Balsa wood, although thin and light, is surprisingly strong and if glued correctly won't fall off. Just think about your rotors; they can spin repeatedly into walls and will still stay intact.

[mrsteven]

but aren't you afraid that the disc may fall of or break if it is so thin?

Balsa wood, although thin and light, is surprisingly strong and if glued correctly won't fall off. Just think about your rotors; they can spin repeatedly into walls and will still stay intact.

with that said, i also had some liquid steel (epoxy), with that I promise you the helicopter could be blown up and the joint between the rotor and disk will be intact
Although that was total over kill i added at the last moment- I would recommend a few coats of CA glue (tried just one at the joint, came off) Don't go CRAZY with it, but use in exess. You don't want a wonderfully long flight to be ruined by the disk falling

[jarrred_1415]

Quick question guys, i'm new at this any my copter keeps turning on its side and moving then like a wright stuff airplane (obviously not in circles though). What causes this? Is it that the copter is top heavy or what?

Can be a multiply things 1. the props aren't balanced. in which case you need to set your helicopter up on a stand so that the motor stick is horizontal and the props can spin freely. and slowy spin them and balance them so that they end up balancing out perfectly horizontal. 2. your motor stick is weak, which is just getting a new one and transfering stuff 3. the props/thrust bearing aren't built straight which the only solution is rebuilding better.

[illusionist]

Quick question guys, i'm new at this any my copter keeps turning on its side and moving then like a wright stuff airplane (obviously not in circles though). What causes this? Is it that the copter is top heavy or what?

Actually, there is a much easier solution than the ones stated above (although those are all things you should check for anyway). Your helicopter is top-heavy. In order to fly vertically, most of the mass has to be concentrated towards the bottom. So simply adding clay should correct this problem. This is why most people would suggest that you build your helicopter under 3.5g, so that you can bring it up to the requirement by adding clay or other material to the bottom end of your helicopter.

[Orange714]

I'm kind of new, and if you added modeling clay would you just stuck it on the bottom of the rotor? Like so the clay would spin along with the rotor? Also when we've tested our helicopter shoots up perfect straight really fast, stays for maybe 5-15 sec and then kinda swoops down in circles. When it lands it has a lot of winds on it. We wind it like 65-75 times with a 10:1 ratio winder and the rubber band is like 10-11 inches (If we wind it any more the rubber snaps, I don't know why....) How would you increase the time? We've tried double banding the rubber band and that didn't work too well....Do we just get better rubber and wind it even more?
Thanks

[chia]

I'm kind of new, and if you added modeling clay would you just stuck it on the bottom of the rotor? Like so the clay would spin along with the rotor? Also when we've tested our helicopter shoots up perfect straight really fast, stays for maybe 5-15 sec and then kinda swoops down in circles. When it lands it has a lot of winds on it. We wind it like 65-75 times with a 10:1 ratio winder and the rubber band is like 10-11 inches (If we wind it any more the rubber snaps, I don't know why....) How would you increase the time? We've tried double banding the rubber band and that didn't work too well....Do we just get better rubber and wind it even more?
Thanks

I would suggest putting it as low on the motor stick as you can, rather than on the rotor itself, since adding weight to the rotor will change the rate at which it turns and how aerodynamic it is, and probably not for the better.
By rubber band, do you mean an actual store-bought circle of rubber, or competition rubber like the stuff you can buy at FAI Model Supply? If it's the former, you may want to consider investing in competition rubber (look through the Rubber thread for links), maybe just a quarter pound to start with. If you already have something like that, are you using a lubricant (silicon-based or Armor-all are what I've heard of)? The rubber can snap pretty easily if you wind it dry, and it might not stay in the air as long.
A couple of posts back there was a discussion on helicopter wobble - maybe that might apply to you. Since your helicopter simply isn't lasting that long in the air, though, it could be a problem with your rotor design (ie pitch?).