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#1
11-10-18, 02:47
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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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#2
12-10-18, 02:45
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975-46
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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#3
15-10-18, 01:54
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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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#4
15-10-18, 23:49
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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. Last edited by Perry Kitson; 17-10-18 at 01:26.
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#5
16-10-18, 02:46
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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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#6
04-11-18, 03:33
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975-46
Related to Robs earlier post (37) I talked with Stew Robertson who was Bill Greggs mechanic about the two radial engined vehicles in the collection. While it was 30 years ago he recollected that the engine in the Sexton required a complete OH and so he tore it down and rebuilt it. This was a machine from England not one fron South Eastern Equip in Georgia. It was a long process especially trying to source parts from Toronto surplus yard, Levy Auto Parts. The Grizzly was running very roughly when it arrived from England and two cylinders, pistons, rods were replaced. Oil pressure was erratic but when repair work was completed it ran fine. This suggests damage from hydrostatic lock perhaps when attempting to start, but this is only a guess after 30 years.
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#8
30-01-20, 20:13
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HUP - but not of the CMP variant
Quote:
(I can post this here - a HUP is a HUP, eh?  )79371912_1014684562202085_541257787301167104_n.jpg Because of the drive-by nature of my own photo I added some more NMPs for clarity. 80325075_1014684612202080_3401083665675976704_n.jpg 79425522_1014753502195191_6632405540636983296_n.jpg
__________________
Regards, Hanno --------------------------
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#9
31-01-20, 02:10
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R975 rear main bearings
I think you make a good point Peter, clearly the large channel around the bearing exterior is an oil channel ( you can see the small holes leading to the interior) so sticking a notch which presumably holds something must restrict or enhance oil flow?? don;t know but at some point will pull a bearing out of a battered crankcase to see.
Hanno, in my book a HUP is a HUP and more importantly in this day and age they have both survived the scrap man! Thanks for the post! B.P.
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#10
25-02-20, 02:18
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R975 rear main bearings
To follow up my last post on rear main bearings I offer a photo of the -46 version, as I have done for most of the other main parts. Note the much heavier flange area. For those not familiar with workings of these engines, the bearing flange sits flush in the crankcase but the projecting threaded portion supports the camshaft.
bearing-46.jpg On another topic, a couple of photos of nine mystery boxes, dug out of storage after almost 70 years...what could they be?? mysteryboxes.jpg All export packed in waxed cheesecloth over heavy cardboard cartons... very nice indeed! mysteryboxes2.jpg Last edited by Bob Phillips; 01-03-20 at 13:19.
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#11
25-02-20, 02:35
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R975
A beautiful sight for a Sherman enthusiast!
Last edited by Bob Phillips; 01-03-20 at 13:12.
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#12
26-02-20, 03:27
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A beautiful sight, indeed! The military packing used back in the day was incredibly good quality.
We had a couple of visitors come by the museum from BAIV, a military restoration company in the Netherlands. When they saw our wrecked Sexton R975 on display, they said the cylinders are going for around 2000 euros each now! So good find. Malcolm
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#13
27-02-20, 03:06
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R975
Malcolm, your appreciation is very much appreciated! Also a very unique smell as they were packed with thick heavy grease inside and outside.
I want to share a few pictures with you, reminiscent of those showing your beat up Sexton engine. This was a motor I tore apart, it looked great on the outside but not so great inside. You can see half a fractured link rod that was laying inside the motor, the piston was smashed to bits, I took out a couple of handfuls of aluminium chunks and look at the smashed up crankcase and the hole/slot cut right through the cylinder base as the rod came out! I suspect this was hydro static lock up induced, as it was a bottom cylinder right beside the oil sump. Must have been noisy for a few minutes as it disintegrated! B.P. smashed1.jpg smashed2.jpg smashed3.jpg Last edited by Bob Phillips; 27-02-20 at 03:25.
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