Item 1012
DESIGN: UniCopter ~ Power Train -
Reduction - Secondary - Belt for Laterally Mounted EngineFor DESIGN: Assembly Item
1011
Drawing:
Goodyear Eagle Pd:
Blue Belt. Belt width is 1.38"
Drive sheave is 38 teeth, 6.667" pitch diameter. RPM is 2056. Allowable HP is 100.
Driven sheave is 40 teeth, 7.018" pitch diameter.
Sheave widths are 1.457"
If room for extra width is available then Green belt could be used. The belt width is 2.07" and the sheave widths are 2.146". Note that the stock SCM clutch is already 3.375" wide. Allowable HP is 150.
Drawing currently shows the Green belt in green and the Blue belt in blue.
Engine gearbox:
Keep rotational spike absorber (dog hub) inside transmission but do not include overload clutch assembly.
All the following is an Old V-belt idea. It was driven from the crankshaft and the rotation was in the wrong direction. Just keep for a while then cut
3VX Gripnotch w/ 7 Grooves by Morse
(Calculations are approximately & are to be redone when details are tightened up. Reduce ratio and sheave diameters)
|
|
Input |
Rotax 912 S at 75%) |
|
|
|
|
Max. HP |
86 |
|
|
|
|
Max. RPM |
5000 |
|
|
|
|
Max. belt speed |
5000 * pi * 5.5 = 7200 fpm |
|
|
|
|
Design selection using 3VX Gripnotch belt Drive (Calculations from Morse catalog. p. G5) |
|
||
|
|
1/ |
3VX |
|
|
|
|
2/ Service factor |
1.1 |
|
|
|
|
Design HP |
86 * 1.1 = 94.6 |
|
|
|
|
3/ d = |
5.5" diameter |
|
|
|
|
D = |
9.0" diameter |
|
|
|
|
|
9.0 / 5.5 = 1.63 |
|
|
|
|
4/ |
5000 rpm |
|
|
|
|
5/ |
7 * 15 = 105 hp. Require 94.6 hp. This is OK. |
|
|
|
|
6/ |
94.6 / 15 = 6.3 sheaves |
|
|
|
|
7/ |
C = Center to Center = 14" This can/will be changed. |
|
|
|
|
|
L = 2C + 1.57 * (D + d) + ((D - d)sq / 4C) |
|
|
|
|
|
= 22 + 1.57 * (14.5) + ((3.5)sq / 56) |
|
|
|
|
|
= 22 + 22.7 + (12.25 / 56) |
|
|
|
|
|
= 44.7 + .22 |
|
|
|
|
|
= 45" |
|
|
|
|
|
Make belt 45" inches. Optibelt 3VX ? |
|
|
|
|
|
See p. 15 & 21 |
|
|
|
|
8/ A/ |
15 hp + .62 hp = 15.62 hp |
|
|
|
|
B/ |
15.62 hp * .96 = 15 hp. |
|
|
|
|
C/ Loss in Arc of Contact |
= (D - d) * 57 / C |
|
|
|
|
|
= 14.25 |
|
|
|
|
Correction Factor |
= .96 |
|
|
|
|
|
15 * .96 = 14.4 hp. |
|
|
|
|
|
14.4 hp * 7 grooves = 100.8 hp. S.F. of 1.17. OK This will be less when ratio is increased and small sheaves diameter is reduced. |
|
|
Back to top | UniCopter Home Page
Last Revised: January 3, 2002