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mrsteven wrote:In terms of rotors, although only one mans opinion, I much prefer NOT having elliptical (egg shaped) rotors. They're much more difficult to build and honestly I don't notice in my experience and watching dozens of people with them, that they help at all.
It seems that more 'experienced' teams try to do it and, with minor successes, they seem to cause havoc amongst them. Often times, I've seen them break and the team was left without a functioning helicopter at our state.

As such, last year I used a tweaked parlor helicopter type design as most people use. I'm very happy with its performance and its beaten every elliptical helicopter in any given competition last season.


Illusionist, in terms of splicing, that generally means cutting in half . . .

Well, I can confidently say that a well-constructed elliptical helicopter will be superior to a parlor copter. The drag reduction is extremely significant. There is a reason all of the top F1D fliers on the planet use elliptical blade shapes instead of a cross-form. The issue is the amount of time it takes to build a good elliptical rotor. It is extremely time consuming and requires a relatively high amount of construction skill.

So, I would not encourage anyone to try an elliptical blade for their first helicopters, however, if you feel you have maximized your parlor copter design and are looking for a place to gain more time...then you should definitely start looking at drag reduction (of which, elliptical blades are a major component)

Speaking of difficult to build, my first blade just went up in flames in the oven =P

Any drying in the oven should be at the lowest setting, well under 200 degrees. Doesn't take much to light off Balsa, as you found.

You might be better just air drying over a heating register.

Some folks have used microwaves to dry, very tricky but some make it work. It can overheat your glue and weaken joints.

I like to just air dry. I've occasionally used the oven, but mine goes as low as 170 F. Still have to be careful. I tried microwaving once, see comment on glue joints.

Jeff Anderson
Livonia, MI

jander14indoor wrote:Any drying in the oven should be at the lowest setting, well under 200 degrees. Doesn't take much to light off Balsa, as you found.

You might be better just air drying over a heating register.

Some folks have used microwaves to dry, very tricky but some make it work. It can overheat your glue and weaken joints.

I like to just air dry. I've occasionally used the oven, but mine goes as low as 170 F. Still have to be careful. I tried microwaving once, see comment on glue joints.

Jeff Anderson
Livonia, MI

Hair dryer in a plastic bag works great, if you have the time you can also make a foam or even cardboad box and cut a hole in it for the hair dryer and you have a custom low heat oven for whatever your building

Question about the Chinook-style rotor setup: Does it still count if one of the rotors stops spinning mid-flight? Because there's a good chance that will happen with two separate motors. The construction parameters define rotors as surfaces that contribute lift by rotating on a common path around a vertical axis. So my question is would the rotor still be valid for the bonus if it's not contributing lift the whole flight time?

lucwilder42 wrote:Question about the Chinook-style rotor setup: Does it still count if one of the rotors stops spinning mid-flight? Because there's a good chance that will happen with two separate motors. The construction parameters define rotors as surfaces that contribute lift by rotating on a common path around a vertical axis. So my question is would the rotor still be valid for the bonus if it's not contributing lift the whole flight time?

thats starting to get into the semantics of the rules (very good question though) with that, i'd ask ur coach to submit a clarification b/c its not well enough defined in the rules to answer definitively.

mrsteven wrote:

lucwilder42 wrote:Question about the Chinook-style rotor setup: Does it still count if one of the rotors stops spinning mid-flight? Because there's a good chance that will happen with two separate motors. The construction parameters define rotors as surfaces that contribute lift by rotating on a common path around a vertical axis. So my question is would the rotor still be valid for the bonus if it's not contributing lift the whole flight time?

thats starting to get into the semantics of the rules (very good question though) with that, i'd ask ur coach to submit a clarification b/c its not well enough defined in the rules to answer definitively.

Before I do that, any unofficial opinions from the chalkers or Mr. Anderson?

lucwilder42 wrote: Before I do that, any unofficial opinions from the chalkers or Mr. Anderson?

I think with the particularly nuanced nature of the question, this will definitely be best dealt with through the official clarification channels. Although, I must note that you don't have to ask your coach to submit a question, students are allowed to ask questions too (unless your team has particular rules), just make sure you phrase it professionally.

chalker7 wrote:

lucwilder42 wrote: Before I do that, any unofficial opinions from the chalkers or Mr. Anderson?

I think with the particularly nuanced nature of the question, this will definitely be best dealt with through the official clarification channels. Although, I must note that you don't have to ask your coach to submit a question, students are allowed to ask questions too (unless your team has particular rules), just make sure you phrase it professionally.

Ok thanks

Usual qualification, this is not a site for clarifications, not official, blah, blah

lucwilder42 wrote:Question about the Chinook-style rotor setup: Does it still count if one of the rotors stops spinning mid-flight? Because there's a good chance that will happen with two separate motors. The construction parameters define rotors as surfaces that contribute lift by rotating on a common path around a vertical axis. So my question is would the rotor still be valid for the bonus if it's not contributing lift the whole flight time?

I assume you are talking about a two motor design Chinook where one motor might run out before the other. On a coaxial copter, we don't stop the timer when the motor runs out until something hits the ground. At first blush, why would a Chinook be any different.

But here's where that subtlety chalker7 mentioned comes in. I'm thinking of a design with two roughly equal rotors and roughly equal motors. I can envision a design where the second rotor is some sort of dummy that spins a few times and then just hangs around for the ride. I'm not sure how I'd rule without seeing the specifics, but to me that doesn't fit the spirit of the bonus and I'd be tempted to say it wasn't a Chinook, so no bonus. And I'm even less sure how event supervisors around the country would rule.

So, ask that clarification, don't wait on your coach, as already stated you can do it.

Jeff Anderson
Livonia, MI