rjohnson442

I was hoping to get some insight from a few of the engineers on here for a project I plan to complete before next ice fishing season.
I built an Ice Shanty and put some skis on it and by the time I was done I thought well hell I can put a motor and some wheels on this
It has to be electric motor because of lake restrictions.
Weight
The shanty is about 60 pounds max loaded with gear (I'm 140 with my 8 pound bunny boots on) so lets say a max weight of 250 pounds me riding it
or a max weight of 100 pounds as an "auto sled"
Electric motors
A razor scooter motor E300 24Volt 250watt .335Hp 2600-2850 RPM
I'm not looking for speed but the most torque I can get. around 3mph would be best.
The motor comes with a 11 tooth sprocket # 25 chain, The largest rear I can find stock is a 60 tooth for a #25 chain. so 11/60 would be a 5.45 gear ratio?

What I'm getting hung up on is the wheel size. I'd like to use studded bike tires around 16-18" for 8-9" of clearance from the bottom of the shanty to get over the snow without plowing it.

So would that motor push 250 pounds(with batteries) on 18" wheels with a gear specs. above?

I also have two 6volt motors from a quad don't know the spec's but
I've taken them and upped it 12v and it was pulling wheelies with my 250 pound buddy in it to the point to where it would flip over. My daughter can ride one for about 10-15 now!

rjohnson442

Other factors I'd say the drag (pulling weight) is about 20 pounds on ski's through 8" of snow with 80 pounds of gear. On Ice or an inch or two of snow I have to keep it from running into me so the drag is virtually zero. I can push start it to overcome the initial torque needed for movement. The lakes flat so I won't be climbing hills with it or anything.
I just can't figure out how to put all the numbers together.
a hp ET calculator will tell me .34hp motor @ 250 pounds will do 15 mph or a 52 second 1/4 mile Wow! But how would I add the torque or Hp needed to overcome the drag in this situation?

Koda

There are so many variables there that a calculator won't help you. Garbage in, garbage out. That motor should push it, especially if you help get it going. Use big wheels and good hubs. Make sure the batteries stay warm. Consider a multi geared trans.

rjohnson442

Man I stayed up till 2am digging through formulas and gear vendors, Torque values based on radius, Newton conversions, Frictional coefficients dc motors and the best I came up with is a 24v motor 250 watt with a gear ration of 10:1. with 1.3 ftlb of torque at the drive gear and 13.00ftlb at the driven gear. Using two motors I should get around 26ftlb of torque then. I attached a scale to the tow rope and pulled it over soggy grass today and was getting a reading of around 19 pounds.(much worse then any snow I've ever pulled in).
In my internet degree of physics last night I learned any torque left over from overcoming a standstill will give me motion. Yay! even if it is only 5ftlb.
If anything I'll at least be able to walk with it and thats the biggest battle of ice fishing is being mobile. Dragging drilling and shoveling gets old fast!

oldcutlass

Why reinvent the wheel. Can't you modify an electric pallet jack to meet your needs with a smaller battery pack?

rjohnson442

I thought about that we have one at work that's dead but I need to be able to lift this thing in and out of a Trooper. I thought about a rascal scooter or something like that but not looking to spend an entire amount of money on this. The motors are 40 bucks a piece and the sprockets like another 30. I have 4 small 12volt 19AH batteries already and the lakes not even a mile wide. I think one would be fine as an auto dragger but two would get me going. and in no snow conditions I'd be cruising

allyolds68

I used to mountain bike a lot. I suggest you take a bicycle out in 8" of snow and try to ride it. Studded or not, bicycle tires do not make headway though snow. After about 3-4" it's next to impossible to ride.


I would suggest a rim constructed from some type of flat plate so it slices and add points on the "tread" similar to a sprocket so it grips the ice.

Koda

Maybe you could put runners on it and drive it with a tiller motor driving a sawblade like some dude did recently.

oldcutlass

I was thinking along the lines of like an electric tug.

rjohnson442

I saw that video and kind of where I got the inspiration from. The local news just did a story on how a couple guys rode those new fat tire bikes across the lake from Put in bay to Cleveland on lake Erie and thats about a 50 mile ride. Wondered about using those tires now?
I figure if I use normal bike tires I'd put them behind the ski tracks where the snow has already been compacted for traction. Or using those thin race tire rims with no wheel and some sort of studs on them to cut down to the ice. I've been scavenging CL for big old saw blades and some of these people want more for a used rusted one then a new blade because it's "antique" or "vintage"