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Re: Helicopters C
Posted: Wed Oct 04, 2017 8:09 pm
by retired1
Dave is taking preorders at this time by email only for delivery in about a month. His website will not be up until the end of Oct or early Nov.
His helicopter is a Sikorsky in the fact that it has 2 rotors that are not coaxial. It is a wild design! Both rotors are pushers. The rotors should be easier to build this year, but the kit has a good bit of "cables" which some might have a bit of a problem with. He told me that he has had 2:30 times in an 8 foot ceiling and that it is very stable.
Each rotor has its own rubber band. My thought is that it will either take 2 torque meters, or one with a board to transfer the wound motor to until it can be loaded on the chopper. It will be interesting to see what his instructions have to say.
Re: Helicopters C
Posted: Thu Oct 05, 2017 5:09 am
by Unome
retired1 wrote:Dave is taking preorders at this time by email only for delivery in about a month. His website will not be up until the end of Oct or early Nov.
His helicopter is a Sikorsky in the fact that it has 2 rotors that are not coaxial. It is a wild design! Both rotors are pushers. The rotors should be easier to build this year, but the kit has a good bit of "cables" which some might have a bit of a problem with. He told me that he has had 2:30 times in an 8 foot ceiling and that it is very stable.
Each rotor has its own rubber band. My thought is that it will either take 2 torque meters, or one with a board to transfer the wound motor to until it can be loaded on the chopper. It will be interesting to see what his instructions have to say.
Clearly non-coaxial is the way to go, unless someone has a 6 minute coaxial...
Re: Helicopters C
Posted: Thu Oct 05, 2017 5:24 am
by andrew lorino
Dumb idea time! Couldn't you use one rubber band if you built it like a normal model but used really tiny bevel gears to turn both rotors 90* off of the common axis pointed in the same direction?
Re: Helicopters C
Posted: Thu Oct 05, 2017 5:33 am
by Unome
andrew lorino wrote:Dumb idea time! Couldn't you use one rubber band if you built it like a normal model but used really tiny bevel gears to turn both rotors 90* off of the common axis pointed in the same direction?
Those would have to be pretty well made. I'd imagine you would lose a lot of torque to the gears, but I guess it could work. I think the "standard" non-coaxial designs rotate the axes with a spring transfer of some sort (I can't remember exactly).
Re: Helicopters C
Posted: Thu Oct 05, 2017 1:13 pm
by Raleway
andrew lorino wrote:Dumb idea time! Couldn't you use one rubber band if you built it like a normal model but used really tiny bevel gears to turn both rotors 90* off of the common axis pointed in the same direction?
That's the second train of thought yes

However, the gears would need to be well... perfect to work as the inefficiencies and friction would hold significant values in determining how long the helicopter would fly for. Experimenting with that could be a possibility!
Re: Helicopters C
Posted: Thu Oct 05, 2017 3:49 pm
by retired1
It might shock you the number of teams that show up for a competition that have not taken advantage of the bonuses when offered.
Re: Helicopters C
Posted: Thu Oct 05, 2017 5:45 pm
by ScottMaurer19
retired1 wrote:It might shock you the number of teams that show up for a competition that have not taken advantage of the bonuses when offered.
Out of all the bonuses the only one that teams could undersandably miss is the chinook bonus. Every team should be able to take advantage of both the colored rotor and the preflight bonus with ease.
Re: Helicopters C
Posted: Thu Oct 05, 2017 6:21 pm
by Unome
ScottMaurer19 wrote:retired1 wrote:It might shock you the number of teams that show up for a competition that have not taken advantage of the bonuses when offered.
Out of all the bonuses the only one that teams could undersandably miss is the chinook bonus. Every team should be able to take advantage of both the colored rotor and the preflight bonus with ease.
As I'm sure you're aware, easy != most people doing it - Robo Cross 2015 illustrates this point quite well, with 180 points being a medal-worthy score at regional tournaments in Georgia.
Re: Helicopters C
Posted: Fri Oct 06, 2017 4:38 am
by ScottMaurer19
Unome wrote:ScottMaurer19 wrote:retired1 wrote:It might shock you the number of teams that show up for a competition that have not taken advantage of the bonuses when offered.
Out of all the bonuses the only one that teams could undersandably miss is the chinook bonus. Every team should be able to take advantage of both the colored rotor and the preflight bonus with ease.
As I'm sure you're aware, easy != most people doing it - Robo Cross 2015 illustrates this point quite well, with 180 points being a medal-worthy score at regional tournaments in Georgia.
As I said, two of the bonues are easy and SHOULD be utilized by every team. I do agree that many teams will not use them.
Re: Helicopters C
Posted: Mon Oct 16, 2017 7:46 pm
by Ten086
Hey, so I've been looking through past years' forums and am just very confused in general. I did the event last year but was Not Great because I was just trying to get my helicopter to actually go up, so I'm trying to figure a few things out this year. I just want to say these are really dumb, basic questions because I don't know like anything about physics.
First of all, for the chinook design, a lot of people were talking about transmission systems for horizontal motors. Is using some kind of gear system very common? How do you even connect a rubber band to a gear like that..? And wouldn't that be quite heavy? Sorry, I feel really stupid because I've never really done anything with gears before and can't visualize how that would work. Does simply using thin tubes either curved or bent at a 90 degree angle also work?
Also, after struggling a lot last year with testing rubber bands, I figured I should probably actually like learn about torque...where can you get a torque meter and how do you use one with a rubber band? Again, sorry to anyone who's probably cringing at how dumb I am. I read posts, especially Jeff Anderson's, about how to use a torque meter to compare data and such but I don't even know how to use a torque meter period.....
For lubricating rubber bands, is armor-all considered the best lubricant? I remember something about using hand lotion, wouldn't that be bad for rubber bands?
Is the Freedom Flight kit really doing a chinook design this year? I'm kind of sad because our school's team just like didn't get funding this year because the money isn't for "classroom purposes" so we're frantically trying to raise money for builds, and I feel like it's not possible to be competitive in helicopters without the kit.
Sorry for such a long post.