Belt Drive for an Ultralight!
I only have access to a limited 2D CAD program from www.emachineshop.com. I found some Plans for a Belt Drive originally for a SOLO 210 / Hirth F-36 (15hp) Engine, both 210cc with a Muffler. A 210cc, 2 Stroke with some upgrades in Carb Size and CR and use a Tuned Pipe can make 210cc/7cc = 30hp@6500rpm. A Rotax 277UL (268cc/7cc = 38.2hp@6500rpm ) http://www.recpower.com/hirth.htm The Belt Drive use's a 12mm (0.4724395") Back Plate made of 6061 Aluminum Plate. I would like to Adapt it for other Singles Rotax 277, JLO, Sachs, Honda/Clone Engines in the 20hp to 40hp Range. Can someone tell me how much Force (Thrust) these (3) Plates can Handle?
1/2"
3/4"
1.0"
14 Answers
A 25hp Engine using a 56 x 24 Prop makes about: Static Thrust = 164.80 lbs and needs 25.055hp.
A 30hp Engine using a 58 x 25 Prop makes about: Static Thrust = 189.64 lbs and needs 30.032hp.
A 35hp Engine using a 60 x 25 Prop makes about: Static Thrust = 217.18 lbs and needs 34.393hp.
A 40hp Engine using a 62x25 Prop makes about: Static Thrust = 247.61 lbs and needs 39.213hp.
Would like to make just one Plate that covers all of these. There was another Drawing with Electric Start Option that has to be Thicker, thinking 1.0". Starter Pad is 18mm.
Here is a Nice Belt Drive made for the Honda/Clone GX390+ Type Single Cylinder Engines. There up to (96mm x 86.5mm) 626.3cc today. The GX390 Case can be Big Bored to 100mm. 86.5mm is the largest Stroke I have seen offered. JLO, Sachs, Rotax, etc., made some Large 2 Stroke Singles up to a JLO 395cc. I'm in the process of building a JLO Single a L-372/L-380 372cc. If I pull the Iron Sleeve and use Nikasil I would have minimum a 420cc Single Cylinder Engine. With Nikasil you Save Weight and less chance of a Siezure. A 2 Stroke at 420cc/7cc= 60hp.
The Rotax 277F/277UL (72mm x 66mm) 268.4cc has (4) Mounting Bolt Holes on the PTO Case that are Offset. This is a 277F Skidoo/Rotax PTO Case. The 277UL Case has an O-Ring groove around PTO Area for mounting a Gear Drive. The 277F is what I'm wanting to Adapt a Belt Drive to first. Rotax rated it 26hp@6250rpm on Ultralights, 28hp@6400rpm on Scat Hover Craft, both used Mufflers. The 277F (Fan Cooled) on most Snowmobiles are rated at 7000rpm. With a Good Tuned Pipe a 277F, 268cc/7cc= 38.2hp@6500rpm is possible. It can be Big Bored to 82mm.
A Typical Belt Drive profile.
A Challenger/Hirth Belt Drive for the Rotax 582UL(65hp) uses a 1.0" Back Plate.
Here is a Stl File of what I'm thinking 1/2" Thick
Here is a Stl File of what I'm thinking 3/4" Thick.
Here is a Stl File of what I'm thinking 1.0" Thick.
Here is a Step file 1.0" backplate.
Here is a Step file .75" backplate.
Here is a Step file .5" backplate.
Here is a DXF file.
