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Helis and fixed wing

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IRCHA 4345
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Thursday, January 6, 2011

CB100 #2 Rebuild

A week or so ago the frame on CB100#2 cracked along a mold seam. To fix it I would obviously need to replace the frame, which meant a complete rebuild of the heli.

Here's what the frame looks like. the top is the replacement, the bottom the one in use. Remember to keep the main rotor bearings. They don't come with the frame. There is one on top, and one on the bottom of the frame.  I  removed them and soaked them in silicone lubricant while I did the rebuild.

I completely disassembled the heli. That took about 5 minutes!

I had to cut away the old frame from the CF boom I had made in an earlier modification, and cleaned up the end. I placed it in the boom hole on the new frame, secured with a little CA and held in place by the stay screw.

I found that in removing the boom with the Dremel, despite trying to take precautions, I knicked the delicate silicone covering of one of the three tail motor wires. To repair it I would have to add a section of wire I kept from a previous repair, between the plug and the motor, as in removing the damaged section I would come up a tad short. I spent about half an hour laboriously soldering, only to find on reconnecting the tail motor there was no juice. The solders were good, but because the wires are so fine I suspect in heating the shrink wrap I separated a solder somewhere. This was an excuse to change out the entire wire with a new one.  This took only a few minutes, and everything worked fine!

Reassembly. Motor, servos, rotor, main gear (lubed up), with the bearings taken out of their lube bath. Then the skids and battery tray.  Repinned the Jesus pin with a little Loctite

Took her up for about 6 packs in the house! The observant among you will notice the broken main blade... Also replaced a cracked tail blade. The last flight ended up a bit nasty as I was getting bored and cocky. Haven't broken a CB100 blade in a long time, didn't realize I was out. Helidirect only has the Harden blades, but are currently out of stock, so ordered some regular ones from WOWHobbies...

I also looked at the large aluminum box for the CB100 so I can easily take it with me on trips to Meridian, but the shipping was as much as the box! The $24 box was going to cost me about that much to ship! Removed it from the cart... so much for an impulse buy.  Shipping for the parts dropped to about $6. I really do want that box though...

I do like these little 100's. Yeah, a Blade mSR is swifter and could bind with my Dx6i, but this little bugger got me into heli's. They are fun to fly around the house and in the garage (hence the broken blades), and to hover in the Man Cave. I will always keep one of these around.

1 comment :

  1. Ken,

    Thanks for the description on the rebuild. I just got my CB100 a couple weeks ago and broke the frame. Your tip about the bearings probably saved my helicopter!