Bubba's Experiment

[AussieJester]

Uhm...prolly wrong here (im good at that LoL) but wouldnt the pitch of the blades be incorrect then... considering your turning just the prop and not the motor around as would be the case if it was still connected to a pc fan.

 

[dontsendbubbamail]

I only had one fan in my parts bin and the hub of the fan fit the diameter of the washer on the prop adapter. The motor is 64 mm, so my calibrated eye ball says the fan diameter is 80 mm. I could cut a fan on the CNC, but thought the blade shape of the computer fan would be more efficient. I thought at first that I could just turn the fan around to get it to blow on the motor, but the twist of the blade is the same. You are just pushing air with the back of the blade instead of the front. if I need to reduce the diameter of the fan, I plan to put it in the drill press and then gently bring a sanding block into contact with the blades.

Bubba

 

[thoxbui]

Does the thread of a screw convert from right hand thread to left hand thread if you just flip it around?
Seriously though, this thread is so cool. Even though I'm no stranger to magnetic materials and motor technology, these little RC motors are still mind bogglingly amazing!

 

[recumpence]

Oh, I thought the pitch was the correct direction, but the curve was wrong.

Sorry, my bad. :wink:

So, just reverse your motor direction and ride backward. That should work!

Matt

 

[TPA]

Could reduce the thickness of the blades, thereby reducing the surface area of each blade.

 

[recumpence]

Bubba,

Did you call me and leave a message the other day? Sorry, my life has been insane lately. My wife was hit from a clueless woman in a huge SUV (totalling our van) the other day and I just got back from a tooth extraction 45 minutes ago. I can probably talk Sunday. :wink:

Matt

 

[dontsendbubbamail]

I went for the first test ride with the lipo 48V battery. Handling with the lighter setup was much improved. Top speed was 30mph and I am very happy with that. Don't think I want to go any faster with the pusher trailer. There was some motor cut out at about 3/4 throttle. If I accelerated slowly, I could sometimes get to full throttle. Matt's advice is that it may be the low voltage cutoff setting being too high and or the timing not being set to low. Tomorrow looks to be rainy, so I will adjust the settings and wait for dry roads.

The handling of the one wheel trailer is acceptable as long as it is empty. From a trailer perspective being empty is not good. I might try converting to two wheels to see if I can get more stability with a load in the trailer.

Bubba

 

[dontsendbubbamail]

I tried setting the the timing to low and lowering the low voltage cut off, but I still have the cut out problem when briskly accelerating. It also starts cutting out when going up a steep hill. Sometimes the controller shuts down when this happens and the controller led is constantly flashing. The controller manual doesn't say what a constantly flashing error code would be. I will be sending an email to Castle Creations to ask them about this.

I went on a 25 mail ride today and had to stop half way to let the motor cool off. It doesn't like the 48 volts. Now the dilemma is to decide what to do next. Do I reconfigure the lipo battery into a 24 volt configuration or do I buy a motor that can handle 48 volts?

Bubba

 

[recumpence]

Sounds like the ESC does not like the motor load or your BMS is cutting out. I would bet the ESC is not able to keep sync with that motor under very high load.

Matt

 

[dontsendbubbamail]

I have a 60 amp fuse that I am going to put in tomorrow. If it blows that would mean it is the 65 amp bms that is causing the problem.

Bubba

 

[dontsendbubbamail]

Put the 60 amp fuse in. The motor cut out but the fuse never blew. It is looking like my problem is timing related.

Bubba

 

[gofast]

This was a very interesting thread, wow, now I have lots to dream about. Any other threads on motorized or electric pushtrailers?

 

[dontsendbubbamail]

There are others doing trailers. I don't have any specific link. One down side of a trailer is tire wear. The threads or the tire are showing after 100 miles.

I killed off my bms today. I was making some mods and dropped the bms on some metal. Lots of sparks. OOPS! Anyone know of a good source for a new bms?

Bubba

 

[dontsendbubbamail]

I did a 6 mile test ride on 24 volt lead acids. Most of it was just riding up and down the hills on either side of a creek near my house under WOT. WOT with my current sprockets is only 15 mph on the flats. My new faster sprockets should be here tomorrow. This was just at test to see how hot the motor would get. I was pleased that the motor only got warm and I could not detect any increase in controller temp.

The other good news is that I didn’t get any cutting out of the motor. Even when I rode up my friend’s very steep driveway there was no cut out. I don’t know the percent grade, but when you ride up it; your front wheel is popping off the pavement with each pedal stroke. There was a little bit of pedaling on my part because I was hearing some crunchy grinding from the chain going to the wheel. This was the most stress that I have put on the drive train and now I see that the sprocket on the drive clutch is not quite in the same plane as the sprocket on the wheel. A few shims under the motor box should fix this. The controller did get warm for the first time.

This little motor likes 24v.

Bubba

 

[dnmun]

tyler saidYou can even pry off the bezel and start the needle at -50 for a 100A range )

not true. current capacity is still determined by the shunt that creates the voltage across the meter coil, the left side is current flowing in one direction, the right side is current flowing in the other direction.

 

[TylerDurden]

So, if you pull more than +50A the meter will go backwards?

 

[dontsendbubbamail]

It just so happens that I bought one of those meters yesterday. I hooked it up and loaded the wheel by pressing a bock of wood against it. It go up to maybe 10 amps. I could not load it enough to max out the motor. Running the power to the handle bars is not to appealing, so I think that I will go to plan B. That would be to break down and buy a data logger.

Bubba

 

[dontsendbubbamail]

I tried the faster gearing. With the highest gearing I could almost hit 30 mph. This was a little beyond my comfort level for a pusher design. The down side is the motor over heats in about 10 seconds at WOT. My little motor works best on 24v and geared to go 20 mph. As a pusher for my tandem, it will meet the need. The only problem now is that the acceleration experienced with the taller gearing has created a need for speed. I also would hate to waste the HV controller on 24volts. I will have to mull it over a while before deciding what to do next. Do I reconfigure my battery to 24v or just get a 48v motor?

I feel that I have been able to demonstrate that you can use an RC motor without being a machinist. The only part that would be difficult to create with hand tools was the adapter for attaching the sprocket to the wheel. Having a CNC machine made creating the adapter easy. If I didn’t have a CNC machine, I would have used a disk brake mountain bike hub to attach the sprocket. Using red Loctite to hold the slip fit 18 tooth sprocket on the roller clutch has been successful.

Bubba

 

[docnjoj]

I gather that the roller clutch assembly had threads rotating with the rotation of the freewheel, so without the red Loctite it woulda come off?
otherDoc

 

[recumpence]

Nope, he is using a one way bearing (roller clutch) on the sprocket at the ouput shaft. It operates (essentially) as a freewheel.

Matt

 

[dontsendbubbamail]

There are no threads. The clutch runs on the 1/2" jack shaft and it has an OD of 3/4". It is a slip fit between the clutch and the sprocket. Red Loctite holds it together. To do a press fit like Scott did, you have to be or have access to a machinist / lathe.


Bubba

 

[docnjoj]

Ah ha! Did U use the one way because of the small gear diameter?
otherDoc

 

[dontsendbubbamail]

I choose the clutch because it was the easiest and cheapest way to get the freewheeling action. If I put the freewheel on the hub, I would have had to get a new wheel with a rear hub, to replace the front hub that came with the trailer, and spread the stays a lot. On the first page of this thread, you can see that the sprocket for the wheel is bolted on. An 18 tooth sprocket was the smallest I could order that had a 3/4" bore for the clutch.

Bubba

 

[docnjoj]

Gotcha Bubba!
otherDoc

 

[dontsendbubbamail]

Bubba is going to be in trouble if his wife sees the credit card bill. I decided to go with the HXT 80-100 B and ordered an Eagle Tree Logger. If you don't hear from me again, call the cops and tell them my wife did it. (Just kidding :wink: about calling the cops )

Bubba