Helicopters C

[BuildingFriend]

In increasing stability (as the 2/2 heli usually 50/50 on wright stuff or amazing flight times), would putting 1/16 by 1/16 wood on the motor stick increase stiffness and thus minimize the warping that occurs while attaching a taut rubber? We already have 3 nylon supports. Also, what is everyone's opinion of CF spars vs traditional wooden spars? I don't know the MIT scores (someone please update me!) but it seems national scores this year will be in the amazing 3 45 range which means there will be no time to trim and see if something goes wrong.

You really think helicopters will reach 3:45 at nats??? Seems very unlikely considering current and past scores. I'm quite sure that the top MIT times were in the 1:50's or a little over 2:00 (went second or third to last time block and supervisor said that 1:50-something was the highest).

Oh oops then e.e the winning time at yale was around 2 minutes. I thought some had reached 2 mins preseason or at start and had reached 3 mins at MIT. Bad estimate; revise that to tops 2:45 mins or likely 2:15-2:30

[Bazinga+]

In increasing stability (as the 2/2 heli usually 50/50 on wright stuff or amazing flight times), would putting 1/16 by 1/16 wood on the motor stick increase stiffness and thus minimize the warping that occurs while attaching a taut rubber? We already have 3 nylon supports. Also, what is everyone's opinion of CF spars vs traditional wooden spars? I don't know the MIT scores (someone please update me!) but it seems national scores this year will be in the amazing 3 45 range which means there will be no time to trim and see if something goes wrong.

You really think helicopters will reach 3:45 at nats??? Seems very unlikely considering current and past scores. I'm quite sure that the top MIT times were in the 1:50's or a little over 2:00 (went second or third to last time block and supervisor said that 1:50-something was the highest).

Oh oops then e.e the winning time at yale was around 2 minutes. I thought some had reached 2 mins preseason or at start and had reached 3 mins at MIT. Bad estimate; revise that to tops 2:45 mins or likely 2:15-2:30

Yeah that seems about right. I don't remember how high the heli ceiling at Wright State was, does anyone remember the height? Depending on the height, times could be over 3 minutes.

[calgoddard]

Jeff -

I don't think we disagree.

In my post yesterday I said:

"Yes, all things being equal, the lighter of two SO helicopters will have the advantage."

[BuildingFriend]

We went with the 2017 FFM with a 2 x 2 config, but it was a total disaster. The copter was very unstable, and actually flew sideways instead of straight up (Memories/horrors of our Wright stuff days). It only stayed in the air for like 30 secs. Ugggh!! So, trying to save weight led to unstable and unusable copter.

Think we are gonna go with a 4 x 2 config, with a shorter stick to save some weight. An attempt at this led to the copter staying in the air for 60 secs.

I have 2 NEW questions.
On one of our flights the dime sized top disk fell off the copter as it bounced along the ceiling. (one of our best flights, btw). If I read the rules correctly, rule 5j states "flight stops when any PART of the helicopter touches the floor...". Would a "piece" falling off the copter constitute a PART hitting the ground?

As far as the single blade is concerned. Could you take one of the bottom double blades constructed with the 2017 FFM and just remove the mylar from one side, which eliminates its lifting surface and now makes it a counterweight, as one half of the blade only comes to a radius of 10.0 cm. How is the radius measured? Just the lifting side of the single blade?

Friend, I feel the same Ours crashed into the side of the auditorium, crashed its way up, and ripped two mylars. RIP WS Days

[Bluejet1179]

So I have a .085" band on my helicopter with 1000 winds. There are some winds left after flight. How can I reduce this to get more time?

[_deltaV]

Just to give some perspective, teams were breaking 2:30 at Cornell. At MIT, one team in the time block before me broke something like 2:30 and another team seemed really excited about that. My time of :58 didn't break the top 30 and 1:17 from our B team didn't break the top 20. I think at Nationals this year we're going to see at least one or two teams breaking 3:45. IMHO, at this point 2:00 is the minimum time needed to stay competitive when teams are breaking 2:30 this early in the season

[_deltaV]

Has anybody else with the kit had problems where the ribs just don't reach the bottom spar assembly, and things just don't line up in the way they should? When I built the top rotor I ended up having to cut 1/16" shims from the wood the ribs came on to make sure that the bottom inner spars reached the central rib. Also has anybody else's carbon fiber come severely warped? When I put mine on the jig sometimes it ends up a full centimeter forward/backward/upward of the outer radius of the jig.

[bjt4888]

by_DeltaV,

.020" carbon rod is typically not perfectly straight as a raw material. However, after constructing using jigs as supplied in the Freedom Flight kits, everything should be aligned correctly and straight.

I am coaching four high schools in the Helicopter event and my students have constructed ten Freedom Flight kit helicopters so far and all went together great and all fly great.

As stated in the FF kit instructions, the jigs will align certain parts pretty close and a little "finessing" will be needed to bring things together. I wouldn't add material to the ribs. Our procedure has been to bond the center rib of each rotor blade to the .020" leading edge first, be sure that the rib is then resting against (or taped to) the jig rib support, and then loosen the tape that locates the .020" trailing edge and gently move the TE with a toothpick till it contacts the TE tip of the rib and glue. With fresh CA glue, carbon to balsa joints bond almost instantaneously. Same procedure for the end rib. As recommended in the instructions, we attach the inner rib using Duco Cement, pregluing the .020" LE and TE and the rib tips and then gluing in. This procedure works well for the inner rib as it is so small and it is difficult to see both the LE and TE joint when installing. Duco is slower drying than CA allowing a little time to reposition the small inner rib to get the joints perfect.

My students have won two of the State of Michigan Invitationals so far with slightly modified Freedom Flight Helicopters, so I definitely recommend them.

Good Luck and keep building and testing,

Brian T.

[Goose]

Hey guys

I am having a bit of trouble getting the dimensions of the wings correct for my helicopter. What are you guys using?

Thanks

[Bluejet1179]

Hey guys

I am having a bit of trouble getting the dimensions of the wings correct for my helicopter. What are you guys using?

Thanks

I'm just using freedom flight models jigs that came with the 2017 kit.