B124
DESIGN: SynchroLite ~ Power Train  (for 2 engines)  Overrunning Clutch
Outside Helicopters
Groen Gyrocopter:
Sprag clutches wear out very quickly when there is no shock absorption device between them and the reciprocating engine. [~ from D.K] Particularly reciprocating engines with few power pulses per revolution. Do not use.
See; DESIGN: SynchroLite ~ Power Train  (for 1 engines)  Overrunning Clutch
Types:
See; DESIGN: SynchroLite ~ Power Train  (for 1 engines)  Overrunning Clutch
Location:
Locate between secondary reduction planet holder and mast. The clutch must be roller ramp, cam or ratchet.
Torque at location of clutch:
The torque at the overrunning clutch will be: See 
Note the helicopter will not be flying 100% of the time at 60 horsepower, so design for 50/2 = 25 hp a side.
If the overrunning clutch is to be located on the input side of the second reduction then consider Torrington needle roller clutches.
Largest Torrington is 1.18" ID and 845 inlb (70.4 ftlb).
Morse series B2+ and MarlandRINGSPANN R 200 series seen to be the same.
Torque Values:

Model 
Morse Cam 
MarlandRingSpann 

206 
175 lbft 
195 lbft 

207 
275 lbft 
325 lbft 
Calculations re: Selection of Morse Overrunning Clutch (page C25)
1/ 192 to 205 to 233 ftlb
2/ Overrunning
3/ Gradually applied 1.25 ~to~ 1.75
Note the use of a reciprocating engine and possible misalignment may take the factor up above 1.25. The fact that there is a belt in the drive train plus the inertia of the sheaves and gears etc. may minimize this factor increase.
4/ 192 * 1.25 = 240 ftlb ~to~ 233 * 1.75 = 407 ftlb
5/ Bore requirement is between 1.125" and 2".
6/ Overrunning speed is 600 * 1.20 = 720 RPM. Inner member is the overrunning one.
Item 0260 is 275 ftlb. The associated bearing is taking very little load so use Ultra Light Series bearing.
Calculations re: Selection of MarlandRingSpann
MarlandRINGSPANN R 206 [Item 0524] is 195 ftlb. 1.289" bore 2.440" OD
Requires bearing. The 206K bearing weighs 0.43 lbs.
Questions; 
What is min. and max. speed
Weight
Price
Delivery
Design & Engineering specs.
Note: The 207 is 57% stronger (325 ftlb) than the 206 but it, the bearing, the spacer and the larger housing OD will increase the weight by exactly 1 # per side.
Idea
Consider moving overrunning clutch as far away as possible from planetary gears so that their 'floating' will have as little angular misalignment affect on the clutch as possible.
Warner  Sprag and Roller/Ramp Clutch:
Calculations re: Selection of Warner Overrunning Clutch (Cat P956 8/98, page 12)
Will accept up to 0.025" of misalignment. Where did this come from?
na_{max} = 625 RPM Maximum outerrace drive speed. OK
ni_{min} = 400 RPM Minimum innerrace overrunning speed. OK
1/ Torque to be transmitted: (213 to 229 to 262 ftlbs )

25 HP: in blue 
30 HP: in green 

229 ftlb. 
262 ftlb. 
2a/ Reduced load cycle rate:
10^5 / (600 rpm * 60 min.) = 2.777 hours
1000 hours will be: 1000 *600 * 60 = 36,000,000 load cycles
The load factor fK is there fore 0.6875

= 229 * 0.6875 = 157 
= 262 * 0.6875 = 180 
2/ Service factor: of 1.75, for Gasoline engine and light steady load (low starting torque)
3/ Design torque:
157 * 1.75 = 275 lb.ft. Reduction for load cycle.
229 * 1.75 = 400 lb.ft. No reduction for load cycle.
180 * 1.75 = 315 lb.ft. Reduction for load cycle.
262 * 1.75 = 459 lb.ft. No reduction for load cycle.
4/ Shaft size: 1.375" diameter or less; which is less than the bore of all for clutches.
5/ Overrunning speed: 600 rpm * 1.2 = 720 rpm. (Inner race)
6/ Selection:
Model: 
Torque capacity: 
Bore: 
Weight: 
AS40 
168 lb.ft. 
1.57" 
0.86 lb. 
AS45 
196 lb.ft. 
1.77" 
0.97 lb. 
AS50 
210 lb.ft. 
1.97" 
1.08 lb. 
AS55 
280 lb.ft. 
2.17" 
1.46 lb. 
ASK60 
295 lb.ft. 
2.36" 
1.10 lb. 
This will be used if;
1/ roller ramp overrunning clutch advances around mast during use, or
2/ accurate positioning of azimuth is required.
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Last Revised: February 8, 2005