Light Sport Aircraft Belt Reduction Drive

Light Sport Aircraft
Belt Reduction Drive
Timothy Bourgeois
Transportation Group
Light Sport Aircraft
Advisor: Dr. Pratt
Table of Contents
Project Overview……………………………….1
Design…………………………………………..2
Specifications…………………………………...17
Analysis………………………………………....20
Future Work………………………………….…33
Manufacturing Photographs…………………….34
Project overview
The belt reduction drive (re-drive) project was proposed shortly after the
conclusion of the LSA integration senior project, which mounted the Rotamax
Generation II engine to the fuselage. At the end of this senior project, the group did
several engine run tests. During these tests it was determined that the engine was
producing excessive vibration. We suspected that the vibration was being caused by the
gearbox which came installed on the Gen II engine. In the fall 2008 semester, we were
able to take the gearbox apart and noticed that there was a rubber flexible coupling
between the engine output shaft and the gearbox input. We suspected that the vibration
was originating from a resonance caused by that coupling and created a new coupling
made out of aluminum to test our theory. We did several engine run tests with the new
coupling and found that the vibration was indeed reduced (and its frequency increased)
but not to a level that we felt was acceptable. Having done several engine run tests on the
Rotamax Gen I engine, which had a belt re-drive system, we decided to revisit the idea
and create flight quality one for the Gen II engine. It seemed that the vibration that we
experienced with the Gen I engine was always significantly less than what we
experienced on the Gen I engine with the gearbox. The belt driven design also reduces
the weight of the engine by quite a bit and eliminates the need for a separate gear oil
system.
When we proposed the belt re-drive project, we set out several objectives for it.
First, we wanted a system that could be able to handle interchangeable propeller
sprockets (the large sprocket that attaches to the propeller) so that we could change the
reduction ratio if required. Second, we wanted to be able to tension the belt easily
without the use of an idler wheel. An finally, we wanted a minimum of 1000 hours
between overhauls and a mean time between failure of no more than 2 years. In the
subsequent sections I discuss and show all related documents for the re-drive design,
analysis and component specifications.
PG 1
Design
Our design for the reduction drive and all its components are covered in this
section. The design consists of a belt, 2 sprockets and an upper sprocket support
assembly. The upper sprocket support assembly consists of a shaft, which the propeller
sprocket attaches to, and components that allow the shaft to rotate freely and support it,
such as bearings, bearing support blocks etc. An explosion view of the upper sprocket
support assembly is included in this section. The backbone of the upper sprocket support
assembly is the base bracket. This bracket acts to support the shaft and doubles as a top
engine mount. The bracket bolts to the top of the engine and the back of the bracket
connects, with a single bolt, to the top engine mount link. This design creates a one piece
system that transmits the thrust loads from the upper sprocket support assembly directly
to the fuselage. To tension the belt, shims are placed under the front and rear support
blocks to raise the entire shaft and therefore tighten the belt. The bearings used in the
design are a ball bearing at the front of the shaft near the sprocket and a tapered roller
bearing at the rear. The tapered roller bearing takes all of the thrust load as well as some
radial loads where the ball bearing only takes radial loads. A tapered roller bearing can
take large loads in both the axial and radial direction and was chosen for that reason to
take the thrust loads produced by the propeller.
PG 2
PG 3
1
2
3
4
5
6
7
8
9
Propeller
Gates 31.5 inch Belt
Engine Sprocket
Propeller Sprocket
Propeller Spacer
Top Engine Mount Bolts
Thrust Mount Bolt
Propeller Bolt
Upper Sprocket Support Assembly
1
7
6
9
4
5
8
2
3
5
4
3
2
1
PG 4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Base Bracket
Front Support Block
Rear Support Block
Shim
Shaft
Ball Bearing - SKF 63005-2RS1
Roller Bearing - Timken 07097 07196
Front Spacer
Rear Spacer
Propeller Sprocket
7/8-14 Castelated Nut
5/16-24 Bolt - AN5-46
5/16-24 Stop Nut
5/16-24 Bolt - AN5H-4
13
2
3
11
4
6
9
7
8
10
14
5
1
11
12
Upper Sprocket Support Assembly
5
4
3
2
1
PG 5
1
2
3
4
5
Left Bracket Side
Right Bracket Side
Bottom
Thrust Mount C-bracket *
Upper Strengthener
2
1
5
4
3
* Part cut to size to interface with the thrust mount
All components are TIG welded together
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
BEND
ANGULAR: MACH
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Base Bracket Parts
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
REV
3
SHEET 1 OF 1
SCALE: 1:3 WEIGHT:
DO NOT SCALE DRAWING
2
1
PG 6
1.45
Bend Radius .18
2.364
0.313
0.50
1.505
8
0. 32
0.50
3.00
3
0. 31
0.50
4.340
6.634
5.712
3.00
0.50
2.988
5.212
8
0. 32
0.506
6.18
1.00
2.024
3.00
0
0.50
3
. 31
9.184
4.00
Sheet metal thickness is 0.09
Thrust Mount C-Bracket and Upper Strengthener left out for clarity
4.180
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Support Bracket
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
4130 Steel
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
SHEET 1 OF 1
SCALE: 1:2 WEIGHT:
DO NOT SCALE DRAWING
3
REV
2
1
PG 7
0.550
1.450
1.770
Sheet Metal Thickness is .09
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Upper Strengthener
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
4130 Sheet Metal
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
SHEET 1 OF 1
SCALE: 3:1 WEIGHT:
DO NOT SCALE DRAWING
3
REV
2
1
PG 8
0.50
0.313 THRU
0.50
2X
0.272 0.750
0.50
2.00
1.250 THRU
1.850 0.630
0.750
2.416
3.25
4.00
0.272
1.50
4.00
0.272 holes are tapped with 5/16-24 tap
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Front Support Block
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
6061 Aluminum
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
SHEET 1 OF 1
SCALE: 1:2 WEIGHT:
DO NOT SCALE DRAWING
3
REV
2
1
PG 9
0.50
0.313 THRU
0.50
2X
0.272
1.750 THRU
1.969 0.375
2.00
0.750
0.50
0.750
2.416
3.25
4.00
0.272
4.00
1.50
0.272 holes are tapped with 5/16-24 tap
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Rear Support Block
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
6061 Aluminum
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
SHEET 1 OF 1
SCALE: 1:2 WEIGHT:
DO NOT SCALE DRAWING
3
REV
2
1
PG 10
1.500
0.500
3.750
0.375
0.313
Use desired sheet metal thickness for proper belt tensioning
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
BEND
ANGULAR: MACH
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Shim Profile
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
REV
3
SHEET 1 OF 1
SCALE: 1:1 WEIGHT:
DO NOT SCALE DRAWING
2
1
PG 11
7/8-14 Thread
0.875
0.9843
7/8-14 Thread
1.088
1.278
1.148
1.338
11.145
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
NAME
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
DATE
TITLE:
CHECKED
ENG APPR.
Shaft
MFG APPR.
COMMENTS:
MATERIAL
SIZE DWG. NO.
Mild Steel
A
FINISH
NEXT ASSY
USED ON
APPLICATION
4
SHEET 1 OF 1
SCALE: 1:2 WEIGHT:
DO NOT SCALE DRAWING
3
REV
2
1
PG 12
0.990
0.225
Thickness should be chosen for proper interface with bearing race
Inside diameter can vary slightly to accomodate available tubing
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
MATERIAL
FINISH
USED ON
NEXT ASSY
APPLICATION
4
NAME
DO NOT SCALE DRAWING
3
DATE
TITLE:
CHECKED
ENG APPR.
Front Spacer
MFG APPR.
COMMENTS:
SIZE DWG. NO.
Use available
4130 steel
tubing
REV
A
SHEET 1 OF 1
SCALE: 2:1 WEIGHT:
2
1
PG 13
0.990
0.375
Thickness should be chosen for proper interface with bearing race
Inside diameter can vary slightly to accomodate available tubing
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
<INSERT COMPANY NAME HERE>. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
<INSERT COMPANY NAME HERE> IS
PROHIBITED.
5
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
BEND
ANGULAR: MACH
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
MATERIAL
FINISH
NEXT ASSY
USED ON
APPLICATION
4
NAME
DO NOT SCALE DRAWING
3
DATE
TITLE:
CHECKED
ENG APPR.
Rear Spacer
MFG APPR.
COMMENTS:
SIZE DWG. NO.
Use available
4130 steel
tubing
REV
A
SHEET 1 OF 1
SCALE: 2:1 WEIGHT:
2
1
PG 14
See Gates drawing for groove profile
2.44
.9830 THRU
2.0450 .5000
DETAIL F
SCALE 2 : 1
R.2 Fillet
6x
.2677 THRU
F
R1.90
60.00° TYP
.38 THRU
R1.48
5.56
56 Teeth Evenly Spaced
UNLESS OTHERWISE SPECIFIED:
PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
MESSIAH COLLEGE. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
MESSIAH COLLEGE IS
PROHIBITED.
5
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL
ANGULAR: MACH
BEND
TWO PLACE DECIMAL
THREE PLACE DECIMAL
DRAWN
INTERPRET GEOMETRIC
TOLERANCING PER:
Q.A.
MATERIAL
6061 Aluminum
FINISH
NEXT ASSY
USED ON
APPLICATION
4
NAME
DO NOT SCALE DRAWING
3
DATE
TITLE:
CHECKED
ENG APPR.
Propeller Sprocket
MFG APPR.
COMMENTS:
SIZE DWG. NO.
Drawn By:
Ben Horst
Nate Cross
Tim Bourgeois
REV
A
SHEET 1 OF 1
SCALE: 1:2 WEIGHT:
2
1
PG 15
PG 16
Specifications
All the specifications for the bearings, belt, and sprocket are covered in this
section. The bearing specifications cover bearing dimensions, rated loads, maximum
speeds and weights for both the ball bearing and the tapered roller bearing. The belt
specifications cover the number of teeth, pitch length, weight and the price. The sprocket
specifications cover all of the required dimensions to make the sprocket. As a note, we
increased the width of our propeller sprocket to be able to work with a 50 mm wide belt.
All these specification are located at the following web addresses:
http://www.skf.com/portal/skf/home/products?maincatalogue=1&lang=en&newlink=1_1
_0
http://www.timken.com/en-us/products/Pages/Catalogs.aspx
http://www.gates.com/catalogs/index.cfm?requesting=ptcatalog&location_id=2999
Note: you must create a login account to see this catalogue
PG 17
Ball bearing
Manufacturer
Part Number
SKF
63005-2RS1
Dimensions (inches)
Inside Diam. Outside Diam.
0.9843
1.8504
Width
0.6299
Basic Load Ratings (lbf)
Dynamic
Static
2520
1470
Limiting Speed (RPM)
9500
Mass (lbm)
0.0221
Tapered Roller Bearing
Manufacturer
Cup P/N
Cone P/N
Timken
07097
07196
Dimensions (inches)
Load Factors
Inside Diam. Outside Diam. Width
e Factor
Y Factor
Dynamic C90
0.9843
1.9687
0.5313
0.4
1.49
Load Ratings (lbs)
Dynamic C1 Static C0 Weight (lbf)
1570
6060
6650
0.26
Note: The C1 load rating is the load that will yield an expected life of 1X10^6 revolutions
The C90 load rating is the load that will yield an expected life of 90X10^6 revolutions
PG 18
Belt
List Price
91.89
Manufacturer
Part Number
Gates
800-8MGT-50
Nomber of Teeth
100
Pitch Length (inches)
31.5
Weight (lbf)
0.5
Propeller Sprocket
Number of Teeth Outside Diam.
56
5.56
PG 19
Analysis
All analysis calculations that we did on our project are covered in this section.
The analysis that we completed for this project was a belt pull force calculation, moment
of inertia and gyroscopic moment calculation, bearing support loads calculation, tapered
roller bearing calculations, ball bearing calculations and base bracket finite element
analysis. All of these calculations and their results are shown in this section.
PG 20
PG 21
Moment of Inertia Calculation
inch
radius
Distance
Trial
Added Mass (kg)
Time (sec)
Moment of Inertia
(kg*m^2)
Average MOI
meters
0.5
0.0127
12.875 0.327026
1
0.65
15.29
1st set up
2
0.65
15.03
3
0.65
15.72
1
1.15
11.37
2nd set up
2
1.15
11.68
3
1.15
11.65
1
0.35
21.19
3rd set up
2
0.35
21.37
0.367616
0.35522 0.388584 0.359654 0.379533 0.377586 0.380186 0.386673
0.370473459
0.372257887
0.385719595
3
0.35
21.47
0.3903
The moment of inertia was measured by finding the time it took for a weight attached to a string ,which was wrapped around the shaft, to
move down a certain distance. The weight supplied a constand torque to the shaft. We then used this time and the assumption that there was
constant acceleration to calculate angular acceleration (α) . With this, we were then able to calculate the moment of interia (I) using the formula:
Torque = I*α
PG 22
Gyroscopic Moment Calculation
Propeller RPM
Rate of Turn (deg/sec)
Moment of Inertia (kg*m^2)
Propeller Ang. Speed (rad/sec)
Processional Speed (rad/sec)
Moment (N*m)
Moment (ft*lbf)
2700
45
0.3903
282.7433
0.785398
86.6724
63.9258
Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\Prop Gyro Calc.xls
PG 23
PG 24
PG 25
Ball Bearing
Bearing Properties
C0
1470
Fa/C0
0.068027
X
0.56
Y
2.3
e
0.19
D
47
d
25
Kr
0.025
v
62.75
C
2520
P
P0
dm
Fr min
Fr min
L10
L10 h
Safety Fac.
lbs
mm
mm
Bearing Loads
Propeller Properties
Dynamic
Static
Max RPM
2500 RPM
Radial (Fr)
219.4
78.7 lbf Avg RPM
2200 RPM
Axial (Fa)
100
100 lbf
Fa/Fr
0.4557885
Bearing Mfr. SKF
Part Num. 63005-2RS1
mm^2/s
lbf
Calculations
352.864 lbf
97.22 lbf
36 mm
94.24265 N
21.1866 lbf
364.2332 10^6 Revs.
2759.343 Hours
7.141562
Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\Re-drive Bearing Loads.xls
PG 26
Tapered Roller Bearing
Bearing Properties
K
1.45
C90
1570 lbf
Calculations
Induced thrust 51.79724
Pr
643.92
L10
19.50859
Life
13301.31
Safety Fac
2.438191
lbs
lbs
90E6 Revolutions
Hours
Bearing loads
Radial
159.8 lbf
Axial
400 lbf
Bearing Mfr.
Cup P/N
Cone P/N
Propeller Properties
Avg. RPM
2200 RPM
Timken
07196
07097
PG 27
Bracket Finite Element Analysis Overview
PG 28
Source: \\collabmain\collabtransportation\LSA_Stuff\Redrive_work\IDEAS\Bracket FEA Overview.doc
PG 29
FEA Convergence Study
.08 Element Size
.06 Element Size
PG 30
.04 Element Size
Source: \\collab-main\collabtransportation\LSA_Stuff\Redrive_work\IDEAS\FEA
Convergance.doc
IDEAS files also located in that directory
PG 31
Belt Reduction Drive Budget
Item
Gates Power Grip GT-2 Belt
Timken Tapered Roller Bearing Cone
Timken Tapered Roller Bearing Cup
SKF Sealed Ball Bearing
2 Castellated Nuts
Aluminum Stock
4130 Steel Sheet Metal
Hardware
1018 Steel Rod
Total
$
$
$
$
$
$
$
$
$
$
Cost
77.37
23.48
8.65
45.95
12.62
76.23
29.72
19.48
28.00
321.50
PG 32
Required Future Work
• Finish construction of reduction drive components
(shaft, front and rear spacer and propeller sprocket)
• Remove excess material from support blocks and
propeller sprocket to save weight
• Complete extensive engine run tests
• Disassemble re-drive and do a complete diagnostic to
look for wear, fatigue cracks etc.
PG 33
PG 34
PG 35
PG 36
PG 37