Helicopters C

[coachchuckaahs]

Thanks. They responded well to difficulty, borne out by much testing. The primary heli hit the wall and went to the corner on the first flight, the dreaded 1-minute wall slide. They both immediately said to each other "heli 2". The backup heli was 15 seconds off the primary, but goes up very straight. That got them the 3:11. The primary was doing 3:15 in the hotel room, landing on the bed, but the rise was a bit of a risk, which did happen.

I am proud of my kids. They worked hard, built 10 sets of rotors with various changes, and at least 6 fuselages (more, depending on where you draw the line between repair and build). They tested a LOT of rubber combos, pitch changes (by heating the blade slightly) and other factors. We logged several hundred flights with about 18 columns in our log book. We totally destroyed both Nats fuselages Monday night before Nats, and they built new ones (well, 1-1/2, one motor stick survived) in 3 hours on Wednesday before we left Thursday morning. We test flew at the hotel!

Man, I'm glad its over!

Coach Chuck

[seadog]

did anyone see a decrease in times at the competition? I think the air density was a factor of the lower times. At home in a 9 foot ceiling my partner and I were consistently getting times of above 3:10 however at the competition we got a time of 2:40.

[glouthan]

Thanks. They responded well to difficulty, borne out by much testing. The primary heli hit the wall and went to the corner on the first flight, the dreaded 1-minute wall slide. They both immediately said to each other "heli 2". The backup heli was 15 seconds off the primary, but goes up very straight. That got them the 3:11. The primary was doing 3:15 in the hotel room, landing on the bed, but the rise was a bit of a risk, which did happen.

I am proud of my kids. They worked hard, built 10 sets of rotors with various changes, and at least 6 fuselages (more, depending on where you draw the line between repair and build). They tested a LOT of rubber combos, pitch changes (by heating the blade slightly) and other factors. We logged several hundred flights with about 18 columns in our log book. We totally destroyed both Nats fuselages Monday night before Nats, and they built new ones (well, 1-1/2, one motor stick survived) in 3 hours on Wednesday before we left Thursday morning. We test flew at the hotel!

Man, I'm glad its over!

Coach Chuck

Dang, 3:11, impressive time and a coincidence because I believe that is the exact same time that won the nationals helicopter event in 2012!

Did your team use the Freedom Flight kit or a homemade design? Would you mind posting a picture now that the season is over because I am really curious to see the design! Congrats to your team!

[coachchuckaahs]

It was our own design. But we are on the road for a week. Yellowstone, then college visits. I'll see what I can do after that

Coach Chuck

[Ten086]

It was our own design. But we are on the road for a week. Yellowstone, then college visits. I'll see what I can do after that

Coach Chuck

Congrats to you and your team! Was it a triple rotor Chinook by any chance? I was hoping to see one of those at the tournament, but it seems like everyone in my time block just had the kit. Are your students willing to post a picture of their helicopter on the Best of 2018 builds page after the trip? Hope you all have fun!

[coachchuckaahs]

Two rotor. Lots of carbon features to get under 3g

Can you send a link to that best of page?

Coach Chuck

[PM2017]

Two rotor. Lots of carbon features to get under 3g

Can you send a link to that best of page?

Coach Chuck

Here you go: https://scioly.org/wiki/index.php/The_Best_of_2018

[glouthan]

Not sure if anyone is still on these forums but since the 2018 season is over I decided to compile a video showcasing our helicopter designs from the 2018 season, including a TRIPLE ROTOR chinook helicopter! Check out the video to see it!

https://www.youtube.com/watch?v=CTTWWlr ... e=youtu.be

[CrayolaCrayon]

I love that three rotor design. I wish I had tried something like that. How did you pull that off (with winding, construction, etc.)?

[glouthan]

I love that three rotor design. I wish I had tried something like that. How did you pull that off (with winding, construction, etc.)?

Construction used the same principles as the 2 rotor as in we needed to keep the rotors on the bottom so the center of mass would be lower (more stability) and of course we had to use some sort of stability vane in order to keep the flight variance down. My thinking process behind this design was that it would be more efficient to use a triangle stabilizer instead of the "X" shaped one with 2 rotors as we could get the weight lower per rotor (3g for 2 rotors = 1.5 g/rotor, but with 3 rotors we could try getting the overall weight down past 4.5g, reducing the weight per rotor). As for the rotors 2 were spinning clockwise and one spins counter clockwise - we never had any issues with this configuration and our flights were stable meaning that even over the approx. 100' height ceiling at state the helicopter would remain only a few horizontal feet from where we launched.

Winding was the tricky part. We eventually started using mini binder clips attached onto the motor sticks to hold the rotors in place so that we could wind the next motor without having to hold the other rotor in place. This was especially helpful when all 3 motors were on as only one of us would have to carry it over to our launch spot then we would we would undo the binder clips and release. It would be difficult moving the 3 rotor device while both of us were holding the rotors - risk of breaking the motor sticks would be high!