Helicopters B

[akfackenthal00]

new to this event, so anybody know this:
is the helicopter supposed to stay up for 3 minutes minimum? thx

[retired1]

No, just one second longer than the nearest competitor.
It is getting stronger every year. My guess is that it will take over 2.5 min to win most states and over 3 min to win nationals.

[Aletheia]

My partner decided to drop us out of Rotor Egg Drop and sign up for Helicopters instead, without my knowledge. Three days away from the Invitational. Four other events to study for. All-nighters it is.

Fun.

[akfackenthal00]

if anyone has the parlor copter kit, how do you attach the lower rotor to the lower prop thing? And are you supposed to make 2 hubs? one for each rotor? thx

[retired1]

google helicopter assembly hints. It will take you to Turner Toys site with additional instructions and some pictures.

It is a beginner kit and will not be very competitive at state and definitely at national. My opinion.

[mtn3172]

I am building a helicopter in my stem club at school , and I'm really confused I don't get how to build it and what the heck is flat balsa wood disc .
I have about 11 more day to build.
Please help and tell me if I do something wrong cause im new.

[jander14indoor]

Glad to help where we can, buy its kind of hard to answer non-specific questions via a bulletin board like this. Have you looked at the wiki on this site for helicopters, last years thread when it was div C, and this years thread? There are a lot of suggestions/discussions there. Another resource, the North Carolina SO organization put out some good videos on how to get started with a very simple design. You can find them on their SO site and by searching around youtube.

Now, to your specific question, the flat wooden disk. Its just that, the rules say the highest point of the copter has to be a flat wooden disk the size of a dime. Any thickness, so keep it thin to reduce weight, 1/32 thick wood will do. The rule came about because in the past some team put wooden pokers or sticks on the top that some people thought would drill into the ceiling and hold the copter up longer, but not by aerodynamic forces. This rule was to prevent that.

Jeff Anderson
Livonia, MI

[hogger]

With no limitation on the motor, does anyone have any hints or tips on how to figure out what would be the best motor stick length and how wide or how long the rubber should be?

[retired1]

That all depends on your rotors. Double or quad? What pitch? Then what length is your rubber band length? How many winds does it land with? The bigger the fuselage, the more it weighs thus taking wider rubber. Basically, you start with .125 rubber and work up, then change your boom length and do it again. Then you go back and increase or decrease the rotor pitch and do it again. Most people will start with 12" and work from there. Building the rotors takes the most time. You can swap out a boom or set of rotors in a couple of minutes.

[hogger]

This is my first time doing this event and I am no expert, so here is my thought. Unlike when you have limit on the motor stick length and rubber weight, you don't need to worry much about matching the rotor pitch with the maximum rubber weight of certain width such that the flying model would get to the top of the ceiling as it runs out of the lift power. Since helicopter does not fly in circle like the wrightstuff plane, you can just load up as much as you can such that the motor can keep running as long as possible. If the helicopter hits the ceiling, it can just keep bouncing up and down against the ceiling until the power runs out. This should favor long thin rubber motor that slowly unwind for longer period of time. Try to make as long a motor stick as you can at the minimum weight and as long as it is strong enough to take the tension of the rubber, it should be good. Is there something wrong with this kind of thinking?

I am building the rotors like the plan drawing in the wiki below which look very similar to the freedom flight model kit rotor. There are 2 rotors, one clockwise and counter clockwise with helical twist like having 2 blades with curved ribs and film covering. Next I need to put them on the motor stick and I am contemplating how long the fuselage should be. I will try the 12" length and .125 rubber first as you suggested.

http://scioly.org/phpBB3/gallery/image_ ... age_id=628