Helicopters B

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jander14indoor
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Re: Helicopters B

Post by jander14indoor » February 19th, 2013, 4:15 am

Read back up this chain a little, your question has been answered.

Jeff Anderson
Livonia, MI

PS, short version, it just doesn't matter. Motor stick length has little effect on this event in terms of energy return from your rubber. Now, it MAY have an effect on overall weight, very important, and stiffness, not trivial.

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Re: Helicopters B

Post by hummus_k » February 20th, 2013, 2:56 pm

Can you make last minute adjustments to the helicopter? If so, how much time will you be given?

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Re: Helicopters B

Post by Hosj » February 24th, 2013, 11:48 am

Hello,I have a question, about the test launches.
I built one copter, and did 10 test flights, writing down the six parameters as per the rules. We had a regional competition, and we were planning to build a better copter for states.
My question is, do we have to make a new data sheet with 10 launches with 6 parameters as per the rules, (Of course we would still test it excessivly, just not record it.) or can we circumvent that and focus on testing?
Nationals 2013: Meteorology 2nd, Water Quality 7th, Dynamic Planet 28th, Helicopters 41st
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Re: Helicopters B

Post by jander14indoor » February 24th, 2013, 1:01 pm

Hmmm, I think you missed the point. WHY would you test and NOT record the data. Do you have a perfect memory? We didn't put the data requirement in the rules for us. We put them in there for YOU. The whole point of this event is experimentation! If you aren't keeping the data, what's the point of the experiment?

Now, as far as the rules and scoring, as usual, this is not the official place, blah, blah...

There is no additional reward beyond the 10, so no you don't have to show more to the event supervisor.

But really, see the first paragraph. Data is all to your benefit. Keep the records, look at them, analyze them, understand them. Its the only way to continuously improve. And in the end, it doesn't hurt to show the event supervisors more than required.

Jeff Anderson
Livonia, MI

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Re: Helicopters B

Post by chalker7 » February 24th, 2013, 4:15 pm

jander14indoor wrote:Hmmm, I think you missed the point. WHY would you test and NOT record the data. Do you have a perfect memory? We didn't put the data requirement in the rules for us. We put them in there for YOU. The whole point of this event is experimentation! If you aren't keeping the data, what's the point of the experiment?

Now, as far as the rules and scoring, as usual, this is not the official place, blah, blah...

There is no additional reward beyond the 10, so no you don't have to show more to the event supervisor.

But really, see the first paragraph. Data is all to your benefit. Keep the records, look at them, analyze them, understand them. Its the only way to continuously improve. And in the end, it doesn't hurt to show the event supervisors more than required.

Jeff Anderson
Livonia, MI
Here's a little anecdotal evidence to support this (if you don't believe the scientific method in general.) Having supervised this and other flying events for years, I can always tell when I team is going to perform well without ever seeing their helicopter or airplane. If they hand me a notebook filled with WAY more data than required, I know they'll do great. If they give me the minimum, it's totally random. If they don't have a log at all, I know they are unlikely to get a good time.
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Re: Helicopters B

Post by leichen21 » February 28th, 2013, 7:17 am

My friend and I made a helicopter from IMS Parlor Copter kit which has a rotating rotor on top and a fixed rotor on the bottom. Also there is a free rotating vane on tail.

Today we did our first flying trial and it failed: our helicopter can not fly. We did 20 winds of the rubber band, does that provide enough power?

BTW, the top rotor rotates counter clockwise, so we winded the rubber band clockwise. Do you think the reason is that our helicopter is too heavy for the rotor to lift it up?

We would appreciate your advice very much. Our competition is this Saturday which does not leave us much time.

Thanks a lot in advance for your help,
Karena

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Re: Helicopters B

Post by wlsguy » February 28th, 2013, 7:28 am

leichen21 wrote:My friend and I made a helicopter from IMS Parlor Copter kit which has a rotating rotor on top and a fixed rotor on the bottom. Also there is a free rotating vane on tail.

Today we did our first flying trial and it failed: our helicopter can not fly. We did 20 winds of the rubber band, does that provide enough power?

BTW, the top rotor rotates counter clockwise, so we winded the rubber band clockwise. Do you think the reason is that our helicopter is too heavy for the rotor to lift it up?

We would appreciate your advice very much. Our competition is this Saturday which does not leave us much time.

Thanks a lot in advance for your help,
Karena
You need a whole lot more winds. Ours gets wound to at least 900 minimum.
It sounds like you are winding it with your finger and do not have a winder.
A winder is a required tool in this event.

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Re: Helicopters B

Post by leichen21 » February 28th, 2013, 6:11 pm

wlsguy wrote:
leichen21 wrote:My friend and I made a helicopter from IMS Parlor Copter kit which has a rotating rotor on top and a fixed rotor on the bottom. Also there is a free rotating vane on tail.

Today we did our first flying trial and it failed: our helicopter can not fly. We did 20 winds of the rubber band, does that provide enough power?

BTW, the top rotor rotates counter clockwise, so we winded the rubber band clockwise. Do you think the reason is that our helicopter is too heavy for the rotor to lift it up?

We would appreciate your advice very much. Our competition is this Saturday which does not leave us much time.

Thanks a lot in advance for your help,
Karena
You need a whole lot more winds. Ours gets wound to at least 900 minimum.
It sounds like you are winding it with your finger and do not have a winder.
A winder is a required tool in this event.

Hi wlsguy,

Thanks so much for your advice. We found a winder today which is a 1:16 one. To make 900 winds, that means we will need to wind 56 times, is that correct? Also, does yours use a single band of rubber band for the 900 winds, or do you double the rubber band by looping? What's the size of your rubber band, 1/8 inch, and how long is your rubber band?

The other way to reduce the weight is to use a lighter tissue paper on the rotor. Is there a particular paper that you prefer to use?

Thanks again for your help,
Karena

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Re: Helicopters B

Post by wlsguy » February 28th, 2013, 7:03 pm

I could tell you everything about our helicopter and it really wouldn't do you any good.
Each Helicopter design need to be matched to the rubber thickness, length, and number of winds.
This is the key to the event, finding the right combination (through testing) for your helicopter.

Start by making the rubber band the same length as your hook to hook distance.
Make sure you lube your motors with hand lotion or something.
Wind it up, count the winds, and see what you get.
Try changing 1 of the variables and try again. repeat.

You also might want to try winding off of the helicopter. This prevents a broken rubber band from going through your rotor and breaking something.
One method is to ave a hook in a board to attach one end. You can also try winding a motor until it breaks (off of the helicopter of course).
This will tell you the breakingpoint.

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Re: Helicopters B

Post by fifty_missions » March 11th, 2013, 7:16 pm

On testing a given rubber motor, wind the motor (off the helicopter) to destruction while counting the winds and tracking the torque. The rule of thumb is that the safe maximum winds and torque will be 20% less than that at the point of destruction.

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