R0XoRiZoR
Senior Heliman
Location: Austin, Texas - US
| Fundamental Flaw?Today i received 3 more picco's... 2 worked. 1 was unflyable. Another topic for another time perhaps.. but now i wanted to talk about a problem with adding weight to the nose for forward flight.
This heli is a gyro-copter. Meaning, pitch and roll, auto correct itself. How does it do that? Here's how.
When the heli starts to tip, say, roll-right, the weights on the gyro bar remain at 0 degree's roll for a few seconds longer than the blades+heli. This (using the connecting rods on the main blades) change either the angle of the main blades, or the pitch per blade. Let me explain that part.
See Image #1
With the bird making a hard nose dive, the gyro attempts to compensate. In this photo, it is actually changing the pitch of the forward blade to equal drastically more than that of the aft blade. This would increase lift on the front of the heli, and decrease it on the rear. Thus... correcting any forward movement (theoritically it would make the heli more lible to decrease altitude). Imagine a canoe on the river. The boat gets pushed to the left by wind, and you lean to the right to counteract. The boat stays upright.
If a weight were applied to the nose of the heli, this would create 2 possible area's for battery life draining faster than normal.
1. The heli has to carry more weight. This would make the heli work harder to accomplish the same task. Depending on the weight of the balast used, you can see a dramatic difference in flight times. with my full sized tack method, I lose around 30%.
2. The heli is creating more lift on the front of the heli, and less on the rear of the heli. This would mostly force the heli to work harder to stay in the same altitude, as one position of the blade has far less pitch than the other. The other blade would have far greater pitch, putting a larger load on the motor.
Finding this... i would suggest finding a way to alter the rotor wash, vs the weight distribution. I plan on taking this on myself.
Typically, relocating weight to the front of the bird would promote forward movement... however... being a "gyro" this wouldn't be a very good solution.
Why does my bird move forward with a forward weight then?
Easy. Although the heli blades have some sore of "gyro" action, it is in-efficient. The extra forward movement is just a by-product of the physics of this type of gyro...
Take a fresh new picco out of the box. Immediately put a large.. large weight on the nose. The heli will move forward, but not at the speed of a similar picco that has had 20-30 flights.
This would also explain the stability increase when adding weight to the nose... the tail is getting more rotor wash than the front, and using the tail stickers it kind of creates a "vane-ing" effect. in conjunction with further difficulty for the tail motor to do its job with the extra weight, and vane-ing, the main rotors tend to create some interesting turbulance effects... further hendoring rotational corrections...
More to come...
 |
i may drive in tomorrow to get it so i can post some pix. it flies great.
)
