Flight Trimming

[new horizon]

When determining pitch on a x shaped rotor, is the angle of the pitch the measured angle the angle at the outermost point?

Also, are there any ways to make a helicopter go perfectly straight up? Would having a very low CoG make that happen?

[lllazar]

I'd suppose so since the CG being lower would result in more inertia at the bottom so that wobbling about would be lessened. But a little wobble is good no?

[illusionist]

Sorry, I cant answer the question about the pitch, but I have a question for Illazar. Why would wobble be good at all? Even if it is just a little bit, doesn't it just waste your limited amount of energy that could instead be put towards gaining altitude.

[SFCMS]

Okay, so I am completely lost. Our team started building today, and we couldn't figure out what the name of this piece was. If any of you were in Wright Stuff, what is the name of the thing that attaches the prop to the rubber motor. Its has a hook on it and yeah... Haha sorry for my bad use of terminology.. And, where could I buy those? Really lost...

[lllazar]

Sorry, I cant answer the question about the pitch, but I have a question for Illazar. Why would wobble be good at all? Even if it is just a little bit, doesn't it just waste your limited amount of energy that could instead be put towards gaining altitude.

That's what i was thinking but i remember seeing something about a little wobble being natural, i dunno it'd probably be for your best interest to reduce the wobble as much as possible.

[illusionist]

Yeah, a little is natural, don't worry about, but no wobble is even better.

I believe SCFMS you are referring to the prop shaft? That is attached to the rotor, and put through the prop hanger

[lllazar]

Hmm when we test with a probe at home oddly the helicopter flies, reaches the ceiling, but then backs off of the ceiling after about 10 seconds and starts falling. At our school gym it flies for a lot longer, closer to a minute and a half. We're having a hard time getting the probe to stand straight up, perfectly along the axis of the rotor, might this be the reason why?

[gabuilder]

Hey,

My helicopter wobbles, but it is also five grams so I am reluctant to add more weight and balance it out. Could it be worth it?

Also, I have seen many images of helicopters which seem to have a small piece of poster/wood on the bottom, such as in this picture:
http://www.turnertoys.com/G1/science_ol ... 05_220.jpg

Why have people done this?

Thanks!

[illusionist]

I honestly can't think of any use for the vertical surface at the bottom, other than to maybe off-set the rotation of the motor. But, it is more efficient to let the two rotors spin in opposite directions... Basically, I don't think it is necessary. Many helicopters have done really well without that piece.

[calgoddard]

The picture that appears if you click on the link two posts above appears to illustrate the Gitlow Parlor Copter design. It has a vertical stabilizer made of 1/32" sheet balsa that spins around the axis of a straight pin secured to the bottom of the motor stick. My understanding is that the stabilizer is supposed to improve the helicopter's recovery from ceiling hits.