MLU FORUM  

Go Back   MLU FORUM > MILITARY VEHICLES > The Armour Forum

Notices

Reply
 
Thread Tools Display Modes
  #61  
Old 11-10-18, 03:47
Dennis Cardy Dennis Cardy is offline
Registered User
 
Join Date: May 2017
Location: Surrey British Columbia
Posts: 107
Default

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.
Attached Thumbnails
LZA HUP-3  245 & 246  Aug 57.jpg  
Reply With Quote
  #62  
Old 12-10-18, 03:45
Bob Phillips Bob Phillips is offline
Registered User
 
Join Date: Jul 2010
Location: Ontario
Posts: 239
Default 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?
Reply With Quote
  #63  
Old 15-10-18, 02:54
Dennis Cardy Dennis Cardy is offline
Registered User
 
Join Date: May 2017
Location: Surrey British Columbia
Posts: 107
Default

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.
Attached Thumbnails
r-975-m4ankengine-107w-2.jpg  
Reply With Quote
  #64  
Old 16-10-18, 00:49
Perry Kitson Perry Kitson is offline
metal urgest
 
Join Date: Sep 2008
Location: London, Ont
Posts: 370
Default

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.
__________________
1942 C15A

Last edited by Perry Kitson; 17-10-18 at 02:26.
Reply With Quote
  #65  
Old 16-10-18, 03:46
Dennis Cardy Dennis Cardy is offline
Registered User
 
Join Date: May 2017
Location: Surrey British Columbia
Posts: 107
Default

Yes, exactly. Ground Hover torques the drive line to the max. In another question about the engine...In flight, it's sort-of level.
Attached Thumbnails
Hup-3.jpg  
Reply With Quote
  #66  
Old 04-11-18, 04:33
Bob Phillips Bob Phillips is offline
Registered User
 
Join Date: Jul 2010
Location: Ontario
Posts: 239
Default 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.
Reply With Quote
  #67  
Old 04-11-18, 05:45
rob love rob love is offline
carrier mech
 
Join Date: Feb 2003
Location: Shilo MB, the armpit of Canada
Posts: 5,840
Default

Bob
Interesting info on the two engines. I get so much conjecture and hearsay on these two pieces I don't know what to believe.
Reply With Quote
  #68  
Old 07-12-18, 07:13
Jordan Baker's Avatar
Jordan Baker Jordan Baker is offline
Registered User
 
Join Date: Feb 2003
Location: Hamilton, Ontario
Posts: 3,038
Default

Found this while doing some late night CAM reading.
Attached Thumbnails
0D6A54B0-1823-4679-B1C8-29164D3CFD25.jpeg  
__________________
Jordan Baker
RHLI Museum,
Universal Carrier MKI*, 1942
C15A-wire3, 1944
Willys MB, 1942
Dodge D23c, 1942
10cwt Canadian trailer
Reply With Quote
  #69  
Old 07-12-18, 20:05
Hanno Spoelstra's Avatar
Hanno Spoelstra Hanno Spoelstra is offline
MLU Administrator
 
Join Date: Feb 2003
Location: The Netherlands
Posts: 10,835
Default

Quote:
Originally Posted by Jordan Baker View Post
Found this while doing some late night CAM reading.
Excellent, Ram tank material!

If anyone is wondering what CAM magazine is, see this thread:
http://www.mapleleafup.net/forums/sh...ad.php?t=28361

H.
Reply With Quote
  #70  
Old 10-12-18, 02:08
Bob Phillips Bob Phillips is offline
Registered User
 
Join Date: Jul 2010
Location: Ontario
Posts: 239
Default 975-46

Great poster Jordan!
I should send all interested readers, to an excellent WW2 era report on the R975 recently posted on the Sherman Site. It is the most detailed history I have ever read and I only discovered it a few weeks ago. Many interesting bits of information including;
-many failures due to overheatine, hence C4 styled cylinders
-significant issues with excess fuel during shutdown , therefore degassr shutoff
valves
- over reving of engines (engine as brake) spells quick death to engine
- as C1 and C4 share 85% same parts many C1s converted to C4s during major overhauls
and much more!
BP
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +2. The time now is 14:54.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright © Maple Leaf Up, 2003-2016