Flight Trimming

[kjhsscioly]

Your rotors are only .6 grams each? How wide are they and what are they made of....it's surprising that your motor stick is so heavy.

lllazar, the two rotors I made aren't much heavier, and they were 39 cm, with two intermediate ribs, and mylar ultrafilm attached with superglue. With careful construction, it shouldn't be hard. The motorstick does usually end up being most of the mass, though wire hooks add significant weight.

On another note, has anyone successfully tried/have suggestions for trying airfoil ribs?

[illusionist]

Aerofoil ribs are helpful, I believe that they "catch" more air as the rotor rotates through the air. I don't bother with them, since for sometimes I'll try flying my copter upside down, and there is no way you can do that with aerofoil ribs. Of course, most likely you won't have to do that, so they should be of benefit.

[eta150]

My helicopter is 4.3g and im using 1.8g of rubber. Yet it is still not flying. I am following a basic design of a rotor on top and bottom. The bottom one is fixed to the frame. my wings are 18.5cm x 3.5cm. Any help or should i explain more?

yes its 18.5 on each side. also they are oriented in the correct way. my heli has a total weight of 6.1g. We just did some testing today and we got it to fly but only for around 25sec. I know that is not good. I just want to get over one min, even if other helicopters will beat us by a lot. Another thing is we are using an actual rubber band, getting us only 150 winds. It is 36cm long (when cut to form a line). I read that people are getting in the 1000. Should we look into getting the helicopter rubber to replace it with our rubber band? Will it make a significant difference?

So...
Your helicopter is 4.3 g + 1.8 rubber=6.1g total. That's a fine weight, even if a proportion (I think?) like 4:2 would be better than the current 4.3:1.8. Competition rubber would help. Those 150 winds could be boosted to almost 1000 if you use tan SS + a lubricant (like armor-all or sil-slick). That's a whole lot more time.

[thewinner]

Yeah, competition rubber has a much higher energy release and allows you to get A LOT more winds on the motor. I believe that your helicopter could easily get times of over one minute with Tan SS, if winded correctly.

[illusionist]

When the helicopter is flying, the center of gravity should ideally be near the bottom of the helicopter right? Mine is right smack in the middle of my helicopter. I don't see any great problems with the helicopter wandering around in circles. Should I try to fix this by adding ballast (I'm at 4.05 grams right now)?

[lllazar]

Illusionist, im same right now (same mass too actually), im making a new one this weekend so i can make sure the C of Mass is lower, but i don't see any significant problems either. It flies pretty much straight up....maybe it's because we have the longer motor sticks, they do seem to help a lot with stability.

[Frogger4907]

When the helicopter is flying, the center of gravity should ideally be near the bottom of the helicopter right? Mine is right smack in the middle of my helicopter. I don't see any great problems with the helicopter wandering around in circles. Should I try to fix this by adding ballast (I'm at 4.05 grams right now)?

The best way I've found to eliminate the circles is to put the rotors on the same vertical axis.

[illusionist]

Even while using one fixed and one powered rotor? Because then my thought would be that the motor stick would be spinning off the vertical axis of teh rotors.

[Frogger4907]

Even while using one fixed and one powered rotor? Because then my thought would be that the motor stick would be spinning off the vertical axis of teh rotors.

Yes the motor stick would rotate around the axis, that your rotor is on. or you can make both of them "powered" the rubber band still produces the same amount of torque over the same amount of time then as it would with one of the fixed.

[genius98]

how do u guys make a helicopter less than 4 gs???? is it lie miniature? how long does it fly? and can u give me the design plan?