the gkid bought over one of those gyroscope toys and i stole it for awhile last night and made some interesting discoveries about stability and the cp's hiller flybar/paddles and gyroscopic stability

when you spin up the gyroscope, it will sit on a string or even on the point of a leaning pencil without falling over - the heli should be doing the same but as it falls over, the flybar is supposed to stay level like the gyroscope and correct the heli back upright, but it wasn''t - the flybar was falling over too - why?

to make a long story and a lot of research short, in the tradeoff between performance / response latency time and stability, stability lost - the flybar paddles are too light to be a good gyroscope and supply the heli with a stable horizontal mass to measure and correct deviations out of plane - if the flybar paddles were made of a heavy metal like lead, they would produce the desired horizontal gyroscopic mass but would probably burn out the motor with all that weight, not to mention the tiny servos that have to push them around

but the servos don't actually push the flybar up and down, they only impart a twist, so the paddles do the heavy lifting - as long as we keep aerodynamics on our side, we can go higher on the paddle weight until we see resistance from the motor

so i increased the paddle weight by half again as much - good results - stability increased - went up some more until motor drain increased, so i had to back down again - ended up with an approximate 60% increase in paddle weight - 3 grams becomes more like 5 grams, but maintaining aerodynamics perfectly

i remembered we used to add collar weights to the flybar near the paddles, but this is in the axis of rotation and only helps some, and it is too far in, the weight needs to be at the ends of the paddles - the collars don't address the real issue of inherent gyroscopic stability, which is aerodynamic as well as gyroscopic

by increasing the flybar paddle weight 60%, while still maintaining the aerodynamic shape of the paddles, i achieved what could only be described as a balance point - stablity without loss of resolution or an increase in latency (the time from control input to execution)

bigger or further out hiller paddles are not the answer, neither is any other method except increasing the flybar weight across the outermost portion of the flybar paddle

i tried a bunch of methods for increasing the weight in the exact right place, from rubber grommets as dampers on the flybar, to black electrical tape on the paddles, to lead fishing weights sticky taped to the ends, but the paddle's aerodynamics must be maintained or resolution will decrease and latency will increase - the absolute best would be some outer portion of the flybar paddle being metal, like the last 1/4 inch being metal or something heavier than the current plastic

so far the best plastic paddle mod is to drill a hole in the plastic paddle perpendicular to the rotational axis and as far out toward the tip as possible (while remaining in the area of viable thickness), filling the hole with flybar-sized music wire, then grinding the exposed portions of the wire to make it flush with the plastic aerodynamic surfaces

i hereby call this stabilizing method the 'flybar paddle gyroscopic stability mod', or just 'gyroscopic stability mod' for short, or 'paddle mod' for even shorter


edge


edit: someone may have gone here before - i don't know - if such a thing as a metal-tipped or weighted flybar paddle already exists then let me know asap please

I don't want to ruin your idea. But wouldn't it be very dangerous to have a metal flybar. Isn't it against the AMA saftey code to have metal blades.

I like your thoughts and ideas! This weekend i'm gonna try the known 'collar' mod to see how that goes, but i'll be watching this post on any other experiences! Me too would like the inherent stability of gyro-effect!

Evdreamer; why wake sleeping dogs? Although you're probably right, that's why E-flite packs their brass weights on the CX2 flybar with rubber i think/guess?!

I think that you are barking up the wrong tree. If you want more stability while you are learning use extra collars on the flybar and add electric tape to the blades for weight and impact resistance. Later you will want less weight for better cyclic response.

I used tape on my blades before. They weren't balanced very well. But I didn't know how to balance blades back then. Using plastic blades helped out a lot for me. I also used extra collars. When I down graded my CP Pro to a CP I didn't need the collars any more.

How do you ballance the CP PRo blades. I do the soup can trick with mu CX2 blades but havent read any thing on how to ballance the stock CPPro blades.
Carl

How do you ballance the CP PRo blades. I do the soup can trick with mu CX2 blades but havent read any thing on how to ballance the stock CPPro blades.
Carl

Adding weight to the paddles themselves does the same thing as adding collars. The only difference is that the collars need more weight for the same amount of effect because they're a little further in but the underlying principle is the same. If you want to add more stability and are pushing the limit in terms of weight, you can also use a longer flybar.

What if you made the fly bar longer? This would put the weight of the paddles out farther. Once I broke my CF flybar, I just made my own. I could make it out as far as the rotor blades. . ? no?

Lengthening the flybar may help to an extent, I know people have done it on various models, but there's a trade off in there somewhere. I don't understand it all well enough to know exactly what it is, but remember, the paddles are also acting as the force that drives the lever that drives the main blade pitch. When you make the flybar longer, not only are you moving the weight out which increases the gyroscopic effects, but you're also changing the leverage the paddles have and the distance they need to travel to move the main blades the same amount.