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        Discussion Problem with power transfer to blade?

#1 dsmithwc04 Dec 04, 2012 10:05 PM

Problem with power transfer to blade?
 
Well, I've got a Rotor Concept ID-1 Swat as a project from the office. My goal is to get it flying by the end of the week but I've got a little problem. Upon starting it up I noticed it was extremely unstable and wanted to roll as well as being extremely short on power as it never actually left the ground. Since this heli is a co-axial type I decided to check that both gears were not stripped. I turned the top blades and it felt snug and could feel the motor turning but the bottom blades felt different.

I then held onto both gears and attempted to spin the top blades. As expected it didn't budge.

Then, I held onto the gears and attempted to spin the bottom blades which did move almost freely. It's as if the bottom blades arent securely attached the the gear that is spun by the motor.

So has anybody had this problem?

#2 dsmithwc04 Dec 04, 2012 10:31 PM

Found the culprit. The top gear set which holds on to the outer blade assembly shaft (bottom blade power) is attached to the shaft assembly by two set screws. However, there is no indention into the shaft for these set screws to lock into. The screws rely on the threads in the plastic gear to hold the screw tightly against the shaft in order to transfer power from the gear (which is of course attached to the motor) to the blade shaft assembly. Well, these screws were of course stripping the plastic gear so not really sure on how to properly sort this out. What would a proper method of attaching the gear to the shaft be?

#3 minbari Dec 05, 2012 01:22 PM

if the set screw is stripped in teh gear, buy a new gear. ussualy only about $5

#4 dsmithwc04 Dec 05, 2012 03:08 PM

Is it usual for the set screw to not have an indention in which to crew into? Seams odd that the set screws hold onto the shaft by just the tension alone.

#5 minbari Dec 05, 2012 04:27 PM

quite alot of them are that way, yes.

even the higher end heli have a grub screw that just grabs the tail shaft for tail rotor duty.

#6 Steve_ Dec 05, 2012 07:38 PM

If you can get the shaft out without much trouble, just grind
(or file) a tiny flat spot on the shaft for the grub screw to
rest in.

That is how the majority of pinions mount on 1/10 scale
electric cars.

Careful if you use a Dremel to do this, I cut halfway through
the shaft in about zero seconds and had to replace it.

I guess the best way is to break out the tiny drill bits, and send
a screw right through the shaft, and thread it into the other
side of the hub.
(as long as the shaft is not hardened steel)
The main gear on my Double Horse 9116 mounts that way.

#7 dsmithwc04 Dec 10, 2012 07:35 PM

Got it fixed by drilling an indention into the shaft. I've never gotten this helicoptor to hover much less fly. It is extremely unstable and I'm having a hard time trying to figure out how to go about making adjustments. As soon as I take off to hover it rolls and not input seams to fix it.

#8 Balr14 Dec 10, 2012 11:27 PM

That's a rebadged Walkera LM180Q or something like that, discontinued about 3 years ago. It was terribly unreliable, they couldn't give them away. It requires very delicate swashplate leveling and weight balancing. It think it still has endless pots on the board, too. They require constant adjustments because the gyro is an old style that's very sensitive to current flow and temperature. Watch the lower rotor head, too. It looks like metal but it was plated plastic and doesn't hold on the shaft very well. If you over-tighten the screws, they will strip out the plastic. xheli was selling out the single rotor FP version of this heli about two months ago. I would have bought one if they would have priced it reasonably, because I know how to fix it. They weren't getting any takers, so they decided to try to sell it without the fuselage. What a joke!


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