Saturday, January 11, 2014


I took the trike offroad for the first time... this is just before I started the electric conversion. It did better than I would have thought. I mainly added this because I don't have a picture of the whole trike on this blog. I've ordered some more batteries that should be here in a few days. If you know anything about Spartanburg, SC... this is near the USC Upstate campus. I do a lot of riding from where I live to there and back.

Friday, January 10, 2014

Reduction Drive Details

This has been a bit of a quick and dirty from the outset but evolved pretty quickly into what you see here. The first jackshaft is housed in a piece of 1 inch schedule 40 pipe which has a rough ID of just over .750 inch. I originally had bronze bearings in it but now have needle bearings with an ID of .500 inch and OD of .750 inch. The needle bearing are a tad over size to make for a press fit into a .750 inch hole. The ID of the tubing has a bit of a rough finish so the bearing have so far stayed in place in spite of being a relatively loose fit. I originally had no seals but have since added seals on each end to keep the lube in place.

If  I were to try to duplicate this on a KMX Typhoon (I hope too in the not to distant future) I think I will get some chrome moly tubing which would be both lighter and a better fit.... tho in practice it has not been an issue so far. If it becomes an issue (loose fit) I would probably just use locktight on the bearings to insure that they stay where intended.I machined a piece of aluminum to go into the BB for the second jackshaft. The hole in it is offset to allow for tensioning the belt. It is held in place in the BB by a set screw. It has the same needle bearings and seals as the other shaft though a much tighter fit. I'm using .500 inch hardened shafts both places.
All the pulleys and freewheel adapter are held in place by set screws onto flats ground in the hardened shafts. Not overly elegant but effective. The belts are both 450 mm length 15 mm wide and are the 5m htd tooth style.

Motor Drive Details

A few details about some of the parts I'm using. I've bought quite a few motors and drives from for use on tri copters, quad copters, and RC planes. I have been pleased with their performance and cost. They usually have free shipping on orders over $100 and occasionally have 10% off sales.

The motor is the Tacon Bigfoot 160.... it is a 63mm x 64 mm motor with 245 KV and rated about 2700 watts. It is the biggest motor they sell and normal price is about  $55. I bought three of them... two for trikes and 1 for a Yak 54 with a 72 inch wing span. I just ran it yesterday on the plane with a 16 x 8 prop and it was pulling a little over 50 amps on 44 volts for around 2100 watts at full power. A bigger prop would up the power but probably gonna try it with that prop. I'll try it again in a few days and measure the thrust. 

The drive is a 100 amp HV good for 12s LiPo and came with a couple of undocumented (on their webpage) addons. Four capacitors in parallel across the power input terminals. An interface that I think you can hook between two motor phases and gives you a low level output that could go to a tach or possibly a governor on helicopter applications. I'm not planning on using that. The drive is about $115 and so far is performing well. It does not have the battery eliminator circuit so power for my RBB servo tester is from a 7.4 volt battery. the RBB board has a 5 volt regulator on it.