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  #61  
Old 11-10-18, 02:47
Dennis Cardy Dennis Cardy is offline
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Bob and David. Here's 246 airborne with 245...Two of only three RCN HUP-3's that Canada bought in the Spring of 1954. Piasecki only built 30 of the HUP-3's. So a pretty rare version. Note only 246 carries Labrador's sort of...kind of ..SeaHorse crest. It would seem from these photo's, that the R-975's were not that reliable. Not exactly sure when or where these photo's were taken. But can only have been a month or two into the voyage. BTW..Good notes about the cooling fan being charged over. The cooling fan has direct implications for AFV installations.
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  #62  
Old 12-10-18, 02:45
Bob Phillips Bob Phillips is offline
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A couple of quick points about the helicopter - engine application.
In researching the helicopters two interesting ideas showed up. First, one source claims that the reason the -46 engine was used was because the US military had a surplus of these available. I am not sure what other significant application rthere was for -46 engines in the 1950s, though radial engines were used in other versions of helicopters.
There was also comments about -46 engines having problems, but little clarification as to what the problems may have been. While I am not a radial engine expert my inclination is to believe that radial engines ( like many aero engines) are high maintenance machines. I have heard many anecdotal stories about engine failure in this type of engine ( oil leaks, blown out spark plugs etc etc, but not just Continetal Wright) can anyone add more information about reliability, or problems not associated with ground machine applications?
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  #63  
Old 15-10-18, 01:54
Dennis Cardy Dennis Cardy is offline
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Bob Phillips As you say...aircraft style engines are high maintenance machines. The case is thin aluminum castings with the steel cylinders bolted onto it. They are highly stressed and easy to break. For those installed in MV's, you have to keep the idle at 1000rpm to prevent main bearing failure due to lack of oil. They also break if they are over-revved. The allowable P&W R985 maximum rpm is only about 50 or a 100 rpm below what will hurt the engine. Oil in the lower cylinders ...aircraft or tank...has removed many a cylinder head..never mind entire cylinders. In answer to your question..aircraft type engines require far greater attention to handling. Many of the broken engines are the result of mishandling by the operator. Another hint...don't use the engine to slow your tank descending a hill. It can easily over-rev the engine and blow off a jug. According to the operators manual ...that's what the brakes are for. A lot cheaper to replace the brake pads... than replacing the engine.
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  #64  
Old 15-10-18, 23:49
Perry Kitson Perry Kitson is offline
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Helicopter gearboxes, and by extension engines, are exposed to far greater torque than an aircraft engine and prop pulling air. When a helicopter is hovering, and especially close to the ground, there is a horrendous amount of resistance to moving the air, which can result in "over torquing" the drive train.
I am guessing that helicopter radials could suffer the same fate as tank radials when loads were too great.
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  #65  
Old 16-10-18, 02:46
Dennis Cardy Dennis Cardy is offline
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Yes, exactly. Ground Hover torques the drive line to the max. In another question about the engine...In flight, it's sort-of level.
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