REPORT FLD-CC-001
REPORT SA4000DS, REV. IR COMPLIANCE CHECKLIST FOR FIELD APPROVAL TSO’d 31” DESSER TUNDRA TIRES ON STC’d 10” ABI WHEELS FOR CESSNA 180 & 185 AIRCRAFT
Prepared by: Melvin W. Stene Date: July 1, 2017 1 Report SA4000DS Revision: IR July 01, 2017
Compliance Checklist • • •
ABI STC SA01015SE Desser TSO-62e Approved 31” Tundra Tire, rated at 2,225lbs, speed rated 120mph FAA Advisory Circular AC23-17C
Following the guidance of FAA advisory circular AC23-17C in showing compliance for the installation of “tundra tires” on light airplanes that have a certification basis of CAR 3 the following report has been assembled to insure compliance with the applicable CAR’s. Table #1 below outlines the specific regulations identified in AC23-17C, Appendix 2, “A Compliance Checklist to CAR part 3, as amended Nov. 1, 1949. Both the Cessna 185 and 180 were certified under CAR Part 3 as per TCDS’s, 5A6 and 3A24. The wheels already meet the regulatory requirements by having STC approval under ABI STC SA01765SE for the Cessna 185 and 180 incorporating the installation of 8.50x10 and 29x10 tires. The 31” Desser tires have TSO-62e approval, rated at 2,225lbs and 120mph, and meet the requirements of ABI 10” wheel STC SA01765SE for the tire being rated at, or above, the weight and speed rating of the aircraft. The 29” ABI Bushwheel is STC approved for the Cessna 180 and 185 but does not have TSO approval and its speed rating is reduced to 70mph. Instructions for continued airworthiness will follow the requirements of STC SA01765SE for the ABI wheel assemblies and AC43.13-1b, Chapter 9, sections 9-13 thru 9-19 for the 31” Desser Tires. Recommended tire pressure ranges for the 31” Desser Tires are minimum 8psi and maximum of 20psi.
2 Report SA4000DS Revision: IR July 01, 2017
COMPLIANCE CHECKLIST
CAR
Subject
Evaluation
Means of Compliance
3.71
Weight & Balance
Original W&B: EW 1899.00 CG: 39.16 Moment: 74373.45 • Remove 8.50x6 Wheels & Tires; -52lbs @ 17in • Add 31” Tires & 10” Wheels; 102lbs @ 17in
Analysis
New W&B: EW 1949.0 CG: 38.60 Moment: 75223.45 3.72
Use of Ballast
Not Required: Per TCDS CG range; (+41.9) to (+46.5) at 3350 lb. (+34.5) to (+46.5) at 2100 lb. or less
Analysis
3.73
Empty Weight
No Change
Analysis
3.74
Maximum Weight
No Change
Analysis
3.75
Minimum Weight
No Change
Analysis
3.76
CG Position
No Change
Analysis
3.81
Performance
Appendix A
Analysis, Similarity
3.82
Definition of stalling speeds
Appendix A
Analysis, Similarity
3.83
Stalling Speed
Appendix A
Analysis, Similarity
3.84
Takeoff
Appendix A
Analysis, Similarity
3.85
Climb
Appendix A
Analysis, Similarity
3.86
Landing
Appendix A
Analysis, Similarity
3.105
Flight Characteristics Requirements
Appendix A
Analysis, Similarity
3.143
Ground and Water Characteristics Requirements
Upon installation of the wheel and tire combination ground handling characteristics will be evaluated to insure there are no tendencies to 1) Nose Over 2) Brakes Operate Smoothly with no nose over tendencies 3) No uncontrollable looping tendencies
Design Evaluation, Similarity
3 Report SA4000DS Revision: IR July 01, 2017
3.159
Flutter & Vibration (vibration only)
Upon installation of the wheel and tire combination, vibration will be evaluated to insure the aircraft does not exhibit excessive vibration.
Design Evaluation, Similarity
3.189
Airplane equilibrium
No Change
N/A
3.190
Flaps extended flight conditions
No Change
N/A
3.191
Unsymmetrical flight conditions
No Change
N/A
3.211
General
No Change
N/A
3.212
Pilot Effort
No Change
N/A
3.213
Trim tab effects
No Change
N/A
3.214
Horizontal tail surfaces
No Change
N/A
3.219
Maneuvering Loads
No Change
N/A
3.231
Primary flight controls and systems
No Change
N/A
3.241
Ground Loads
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.242
Design Weight
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.243
Load factor for landing conditions
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.244
Landing cases and attitudes
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.248
Braked roll
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.249
Side load
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.342
Proof of Strength
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.351
Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.353
Shock Absorption Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
4 Report SA4000DS Revision: IR July 01, 2017
3.354
Limit Drop Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.355
Reserve Energy Absorption Drop Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.361
Wheels
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.362
Tires
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.363
Brakes
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.429
Fuel System General
Nearly identical physical dimensions as STC approved Tundra tire which does not impose any Fuel System limitations.
Similarity
3.437
Unusable Fuel
Nearly identical physical dimensions as STC approved Tundra tire which does not impose any Fuel System limitations.
Similarity
3.444
Fuel Tank Sump
No Change
N/A
3.553
Fuel Tank Drains
No Change
N/A
3.583
Cooling Tests
No Change
N/A
3.605
Induction System General
No Change
N/A
3.606
Induction Systems de-icing and antiicing provisions
No Change
N/A
3.699
Landing light installation
Identical landing and taxi stance as the STC’d 29” Bushwheel and wheel configuration so lights would illuminate in an identical manner hence satisfying the regulatory requirements by similarity.
Similarity
3.735
General
No Change
N/A
3.737
Limitations
No Change
N/A
5 Report SA4000DS Revision: IR July 01, 2017
Revision History Revision IR
Description Initial Release
Date
Author
July 01, 2017
W. Stene
6 Report SA4000DS Revision: IR July 01, 2017
Appendix A
Tire Evaluation and Calculations:
The 31” Desser tire is an FAA TSO’d tire with a load rating of 2,225lbs per tire and a speed rating to 120mph. The tire is mounted on an ABI 10” wheel assembly that are STC’d for the Cessna 180 & 185 airplanes and has approval for both 8.50x10 and 29x10 tires.
The load rating of 2,225lbs for the 31” Desser tundra tire meets the requirements for both the Cessna 180 and 185 series aircraft that have a maximum gross weight of 3350lbs.
The physical dimensions and weights of the 31” Desser tire was compared to the STC approved 29” AK Bushwheel. The dimensions measured from actual tires are shown in Table #1.
Tire
Height (d)
Width (w)
31” Desser
30.25”
11.75”
Weight (Including Wheel Assembly) 50 lbs/ea.
29” Bushwheel
30.125”
11.75”
38 lbs/ea.
Table #1: Tire Physical dimensions measured from actual tires and weights.
The ABI 29” Bushwheel are STC approved for both Cessna 180 and 185 aircraft models with physical dimensions similar to the 31” Desser. The ABI 29” Bushwheel is speed rated to 70mph while the 31” Desser tire is speed rated to 120mph.
The difference of weight and dimension of the STC’d 29” ABI Bushwheels and 31” Desser tundra tires will be evaluated to demonstrate compliance with CAR 3 via similarity to the approved Bushwheels. It will be shown that the differences are negligible and that the installation of the 31” Desser meet the regulatory requirements of CAR 3.
7 Report SA4000DS Revision: IR July 01, 2017
Per reference [1], the additive drag coefficient of tire type, C, high floatation tundra tires is given by the following equation: ΔCDtire = ((d x w)/Sref)*ΔCDs ΔCDS = 0.23 For Type C Tires, Reference [1], page 718
Tire
ΔCDtire
31” Desser
0.00326
29” Bushwheel
0.00325
Table #2: ΔCDtire calculations
Per Reference [1], CDmin for the Cessna 180/185 series of airplane is 0.0297. With the total CDmin of the aircraft known we can now evaluate the impact of the differences in ΔCDtire between the 31” Desser tire and the 29” Bushwheel tire on the aircraft.
The difference in ΔCDtire for the 31” Desser tire and 29” Bushwheel is virtually negligible; calculation 0.00326-0.00325 = 0.00001. This difference constitutes an impact of only 0.03% over the total CDmin of the aircraft of 0.0297. Such a small difference would not be measurable and validates the use of similarity of the STC’d 29” Bushwheel tire to the 31” Desser tire as a means of compliance.
The small difference in CDmin and nearly identical physical properties of the tires insures no measurable difference in the flight performance of the aircraft with respect to take-off, climb, and landing vs the STC’d 29” Bushwheels. Therefore the 31” Desser tires meet the regulatory requirements via similarity for CAR’s 3.81,3.84,3.85, & 3.86.
In evaluating the stall speed it would be expected the tires would not impact stall speed or balanced stall characteristics in a measurable manner. This matches the findings in FAA AC23-17C when evaluating the effects of tundra tires on Piper SuperCub type airplanes. The 29” Bushwheels already satisfies the FAA regulatory requirements and the 31” Desser tires are effectively identical in physical and aerodynamic properties hence they meet the regulatory requirements via similarity for CAR’s 3.82 & 3.83.
8 Report SA4000DS Revision: IR July 01, 2017
In evaluating the ground handling characteristics of the 31” Desser Tundra tire a comparison of stiffness to STC approved tires is made. The 31” Desser tire is stiffer than the 29” ABI Bushwheel but slightly softer than the STC approved 29”x11-10 tundra tire. With the stiffness of the 31” Desser tire being in the middle of two STC approved designs it would be reasonable to expect that the tire would exhibit satisfactory ground handling characteristics. It is recognized by the FAA that “Tundra” tires adversely affect handling qualities of the airplane but the FAA has determined these effects not to be significant with regard to safety. To assure compliance it is recommended upon installation of the wheel and tire that ground tests be conducted to insure there are no tendencies to 1) Nose Over 2) Brakes operate smoothly with no nose over tendencies & 3) No uncontrollable looping tendencies exist. Therefore with evaluation to similar designs and ground testing the ground handling characteristics of the wheel and tires would satisfy CAR 3.143
9 Report SA4000DS Revision: IR July 01, 2017
This report is available for use by aircraft owners obtaining a field approval for 31” Desser Tires on 10” AB wheels. This report is not to be used as documentation for submission to obtain an STC.
References 1) General Aviation Aircraft Design, Applied Methods and Procedures. Snorri Gudmundsson
10 Report SA4000DS Revision: IR July 01, 2017
Prepared by: Melvin W. Stene Date: July 1, 2017 1 Report SA4000DS Revision: IR July 01, 2017
Compliance Checklist • • •
ABI STC SA01015SE Desser TSO-62e Approved 31” Tundra Tire, rated at 2,225lbs, speed rated 120mph FAA Advisory Circular AC23-17C
Following the guidance of FAA advisory circular AC23-17C in showing compliance for the installation of “tundra tires” on light airplanes that have a certification basis of CAR 3 the following report has been assembled to insure compliance with the applicable CAR’s. Table #1 below outlines the specific regulations identified in AC23-17C, Appendix 2, “A Compliance Checklist to CAR part 3, as amended Nov. 1, 1949. Both the Cessna 185 and 180 were certified under CAR Part 3 as per TCDS’s, 5A6 and 3A24. The wheels already meet the regulatory requirements by having STC approval under ABI STC SA01765SE for the Cessna 185 and 180 incorporating the installation of 8.50x10 and 29x10 tires. The 31” Desser tires have TSO-62e approval, rated at 2,225lbs and 120mph, and meet the requirements of ABI 10” wheel STC SA01765SE for the tire being rated at, or above, the weight and speed rating of the aircraft. The 29” ABI Bushwheel is STC approved for the Cessna 180 and 185 but does not have TSO approval and its speed rating is reduced to 70mph. Instructions for continued airworthiness will follow the requirements of STC SA01765SE for the ABI wheel assemblies and AC43.13-1b, Chapter 9, sections 9-13 thru 9-19 for the 31” Desser Tires. Recommended tire pressure ranges for the 31” Desser Tires are minimum 8psi and maximum of 20psi.
2 Report SA4000DS Revision: IR July 01, 2017
COMPLIANCE CHECKLIST
CAR
Subject
Evaluation
Means of Compliance
3.71
Weight & Balance
Original W&B: EW 1899.00 CG: 39.16 Moment: 74373.45 • Remove 8.50x6 Wheels & Tires; -52lbs @ 17in • Add 31” Tires & 10” Wheels; 102lbs @ 17in
Analysis
New W&B: EW 1949.0 CG: 38.60 Moment: 75223.45 3.72
Use of Ballast
Not Required: Per TCDS CG range; (+41.9) to (+46.5) at 3350 lb. (+34.5) to (+46.5) at 2100 lb. or less
Analysis
3.73
Empty Weight
No Change
Analysis
3.74
Maximum Weight
No Change
Analysis
3.75
Minimum Weight
No Change
Analysis
3.76
CG Position
No Change
Analysis
3.81
Performance
Appendix A
Analysis, Similarity
3.82
Definition of stalling speeds
Appendix A
Analysis, Similarity
3.83
Stalling Speed
Appendix A
Analysis, Similarity
3.84
Takeoff
Appendix A
Analysis, Similarity
3.85
Climb
Appendix A
Analysis, Similarity
3.86
Landing
Appendix A
Analysis, Similarity
3.105
Flight Characteristics Requirements
Appendix A
Analysis, Similarity
3.143
Ground and Water Characteristics Requirements
Upon installation of the wheel and tire combination ground handling characteristics will be evaluated to insure there are no tendencies to 1) Nose Over 2) Brakes Operate Smoothly with no nose over tendencies 3) No uncontrollable looping tendencies
Design Evaluation, Similarity
3 Report SA4000DS Revision: IR July 01, 2017
3.159
Flutter & Vibration (vibration only)
Upon installation of the wheel and tire combination, vibration will be evaluated to insure the aircraft does not exhibit excessive vibration.
Design Evaluation, Similarity
3.189
Airplane equilibrium
No Change
N/A
3.190
Flaps extended flight conditions
No Change
N/A
3.191
Unsymmetrical flight conditions
No Change
N/A
3.211
General
No Change
N/A
3.212
Pilot Effort
No Change
N/A
3.213
Trim tab effects
No Change
N/A
3.214
Horizontal tail surfaces
No Change
N/A
3.219
Maneuvering Loads
No Change
N/A
3.231
Primary flight controls and systems
No Change
N/A
3.241
Ground Loads
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.242
Design Weight
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.243
Load factor for landing conditions
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.244
Landing cases and attitudes
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.248
Braked roll
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.249
Side load
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.342
Proof of Strength
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.351
Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.353
Shock Absorption Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
4 Report SA4000DS Revision: IR July 01, 2017
3.354
Limit Drop Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.355
Reserve Energy Absorption Drop Tests
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.361
Wheels
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.362
Tires
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.363
Brakes
STC’d Wheels for model of aircraft & TSO’d tires for applicable load and speed.
Analysis, Similarity
3.429
Fuel System General
Nearly identical physical dimensions as STC approved Tundra tire which does not impose any Fuel System limitations.
Similarity
3.437
Unusable Fuel
Nearly identical physical dimensions as STC approved Tundra tire which does not impose any Fuel System limitations.
Similarity
3.444
Fuel Tank Sump
No Change
N/A
3.553
Fuel Tank Drains
No Change
N/A
3.583
Cooling Tests
No Change
N/A
3.605
Induction System General
No Change
N/A
3.606
Induction Systems de-icing and antiicing provisions
No Change
N/A
3.699
Landing light installation
Identical landing and taxi stance as the STC’d 29” Bushwheel and wheel configuration so lights would illuminate in an identical manner hence satisfying the regulatory requirements by similarity.
Similarity
3.735
General
No Change
N/A
3.737
Limitations
No Change
N/A
5 Report SA4000DS Revision: IR July 01, 2017
Revision History Revision IR
Description Initial Release
Date
Author
July 01, 2017
W. Stene
6 Report SA4000DS Revision: IR July 01, 2017
Appendix A
Tire Evaluation and Calculations:
The 31” Desser tire is an FAA TSO’d tire with a load rating of 2,225lbs per tire and a speed rating to 120mph. The tire is mounted on an ABI 10” wheel assembly that are STC’d for the Cessna 180 & 185 airplanes and has approval for both 8.50x10 and 29x10 tires.
The load rating of 2,225lbs for the 31” Desser tundra tire meets the requirements for both the Cessna 180 and 185 series aircraft that have a maximum gross weight of 3350lbs.
The physical dimensions and weights of the 31” Desser tire was compared to the STC approved 29” AK Bushwheel. The dimensions measured from actual tires are shown in Table #1.
Tire
Height (d)
Width (w)
31” Desser
30.25”
11.75”
Weight (Including Wheel Assembly) 50 lbs/ea.
29” Bushwheel
30.125”
11.75”
38 lbs/ea.
Table #1: Tire Physical dimensions measured from actual tires and weights.
The ABI 29” Bushwheel are STC approved for both Cessna 180 and 185 aircraft models with physical dimensions similar to the 31” Desser. The ABI 29” Bushwheel is speed rated to 70mph while the 31” Desser tire is speed rated to 120mph.
The difference of weight and dimension of the STC’d 29” ABI Bushwheels and 31” Desser tundra tires will be evaluated to demonstrate compliance with CAR 3 via similarity to the approved Bushwheels. It will be shown that the differences are negligible and that the installation of the 31” Desser meet the regulatory requirements of CAR 3.
7 Report SA4000DS Revision: IR July 01, 2017
Per reference [1], the additive drag coefficient of tire type, C, high floatation tundra tires is given by the following equation: ΔCDtire = ((d x w)/Sref)*ΔCDs ΔCDS = 0.23 For Type C Tires, Reference [1], page 718
Tire
ΔCDtire
31” Desser
0.00326
29” Bushwheel
0.00325
Table #2: ΔCDtire calculations
Per Reference [1], CDmin for the Cessna 180/185 series of airplane is 0.0297. With the total CDmin of the aircraft known we can now evaluate the impact of the differences in ΔCDtire between the 31” Desser tire and the 29” Bushwheel tire on the aircraft.
The difference in ΔCDtire for the 31” Desser tire and 29” Bushwheel is virtually negligible; calculation 0.00326-0.00325 = 0.00001. This difference constitutes an impact of only 0.03% over the total CDmin of the aircraft of 0.0297. Such a small difference would not be measurable and validates the use of similarity of the STC’d 29” Bushwheel tire to the 31” Desser tire as a means of compliance.
The small difference in CDmin and nearly identical physical properties of the tires insures no measurable difference in the flight performance of the aircraft with respect to take-off, climb, and landing vs the STC’d 29” Bushwheels. Therefore the 31” Desser tires meet the regulatory requirements via similarity for CAR’s 3.81,3.84,3.85, & 3.86.
In evaluating the stall speed it would be expected the tires would not impact stall speed or balanced stall characteristics in a measurable manner. This matches the findings in FAA AC23-17C when evaluating the effects of tundra tires on Piper SuperCub type airplanes. The 29” Bushwheels already satisfies the FAA regulatory requirements and the 31” Desser tires are effectively identical in physical and aerodynamic properties hence they meet the regulatory requirements via similarity for CAR’s 3.82 & 3.83.
8 Report SA4000DS Revision: IR July 01, 2017
In evaluating the ground handling characteristics of the 31” Desser Tundra tire a comparison of stiffness to STC approved tires is made. The 31” Desser tire is stiffer than the 29” ABI Bushwheel but slightly softer than the STC approved 29”x11-10 tundra tire. With the stiffness of the 31” Desser tire being in the middle of two STC approved designs it would be reasonable to expect that the tire would exhibit satisfactory ground handling characteristics. It is recognized by the FAA that “Tundra” tires adversely affect handling qualities of the airplane but the FAA has determined these effects not to be significant with regard to safety. To assure compliance it is recommended upon installation of the wheel and tire that ground tests be conducted to insure there are no tendencies to 1) Nose Over 2) Brakes operate smoothly with no nose over tendencies & 3) No uncontrollable looping tendencies exist. Therefore with evaluation to similar designs and ground testing the ground handling characteristics of the wheel and tires would satisfy CAR 3.143
9 Report SA4000DS Revision: IR July 01, 2017
This report is available for use by aircraft owners obtaining a field approval for 31” Desser Tires on 10” AB wheels. This report is not to be used as documentation for submission to obtain an STC.
References 1) General Aviation Aircraft Design, Applied Methods and Procedures. Snorri Gudmundsson
10 Report SA4000DS Revision: IR July 01, 2017
