Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
How Does The Oiling System On Radials Work?  
User currently offlineBrons2 From United States of America, joined Sep 2001, 3007 posts, RR: 4
Posted (5 years 3 weeks 6 days 8 hours ago) and read 9828 times:

I'm curious about the oiling system on radial engines. With a number of cylinders pointing downwards at various degrees, how does the engine return oil to the sump? And where is that sump, being that the crankshafts are probably what's in the middle, with not much room for a sump. I assume that they would use a dry sump system. But I really don't know.

I'm most familiar with car engines, which let gravity do the work of returning oil into the sump from the heads, and the rods and pistons are splash lubricated.


Firings, if well done, are good for employee morale.
13 replies: All unread, jump to last
 
User currently offlineWingscrubber From UK - England, joined Sep 2001, 845 posts, RR: 0
Reply 1, posted (5 years 3 weeks 6 days 7 hours ago) and read 9822 times:

http://www.5bears.com/curproj.htm

According to this guy who's building one, they're dry-sump with an external oil tank, scavenge pump in the centre of the crankcase, and a pressure pump with hoses to everywhere else.
I wanted to find a diagram but google is holding out on me...



Resident TechOps Troll
User currently offlineJetMech From Australia, joined Mar 2006, 2684 posts, RR: 53
Reply 2, posted (5 years 3 weeks 6 days 1 hour ago) and read 9771 times:

Quoting Brons2 (Thread starter):



Quoting Wingscrubber (Reply 1):

Here is a good link on the R4360.

http://www.enginehistory.org/r-4360.htm

Apparently, the oil system is as descibed by Wingscrubber, that is, a dry sumped, pressure fed system.

http://www.enginehistory.org/P&W/R-4360/4360oil.jpg

Regards, JetMech

[Edited 2009-06-27 01:14:42]


JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineVC10 From United Kingdom, joined Nov 2001, 1406 posts, RR: 16
Reply 3, posted (5 years 3 weeks 5 days 18 hours ago) and read 9697 times:

JetMech
That schematic of the oil system is great except it shows all the oil returning via the scavenge system to the external oil tank, however with these old engines we know that a fair proportion of the oil was either burnt or leaked over the side to become the aircraft's anti corrosion treatment Big grin On the Wright 3350 [Connie fame] normal oil consumption could be 1 US gal per hour with a max allowable of 5 US gals an hour so the external oil tank had to be large and on the 749 was 55 US gals for each engine. On the 1049 they had a slightly smaller oil tank for each engine , but then they had a large central oil tank from which they could transfer oil to any engine in flight.

When coming to a halt after a flight the crew would go through a scavenge procedure so as to remove as much oil as possible from the crankcase, as any left there when the engine was shut down could drain down into the lower cylinders and so cause that cylinder to hydraulically lock on the next attempt to start the engine.

Those were the days

littlevc10  old 


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5722 posts, RR: 11
Reply 4, posted (5 years 3 weeks 5 days 13 hours ago) and read 9648 times:



Quoting VC10 (Reply 3):
lower cylinders and so cause that cylinder to hydraulically lock on the next attempt to start the engine.

Hydrolock is very common on radial engines, and is the reason that you'll often see a person hand propping the engine BACKWARDS three revolutions before starting.


User currently offlineJetMech From Australia, joined Mar 2006, 2684 posts, RR: 53
Reply 5, posted (5 years 3 weeks 5 days ago) and read 9561 times:



Quoting VC10 (Reply 3):
oil was either burnt or leaked over the side to become the aircraft's anti corrosion treatment

Ah yes, the old precision calibrated leak  Smile . I was never fortunate enough to work on any radial engines. The “oldest” thing I worked on was the JT3-D / B707. Apparently, there was a conveyor belt inside the pylon that moved the coal dust down from the wing to the engine  Wink.

I always found it funny when my mechanic would complain of a few drops of oil dripping from the sump of my car when I took it to him for annual inspection. I would always get a stern warning about the dangers to other vehicles and pedestrians from a few stray millilitres of multigrade. If only he could see the puddles of MJ-II left behind by some jet engines!

Quoting VC10 (Reply 3):
hydraulically lock on the next attempt to start the engine.



Quoting AA737-823 (Reply 4):
hand propping the engine BACKWARDS three revolutions before starting.

Would it make a difference which way you hand propped the engine? Both valves are shut on the compression and power strokes, thus, to me at least, hydraulic lock should be detectable in two ways.

If one of the lower pistons stops halfway up the compression stroke, hand propping forwards could produce hydraulic lock. If one of the lower pistons stops half way down the power stroke, hand propping backwards could produce hydraulic lock.

Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineVC10 From United Kingdom, joined Nov 2001, 1406 posts, RR: 16
Reply 6, posted (5 years 3 weeks 4 days 23 hours ago) and read 9556 times:

Well the purpose of pulling through a prop, as i understand it, was to check prior to engine start whether you had a hydraulic lock or not, so allowing you to clear it prior to engine start.

Pulling the prop the wrong way only puts the offending oil in the intake manifold from were it goes back into the cylinder when you try to start. Perhaps thouigh it differs on different engines

The only way I found to clear a hydraulic lock was to open the cowlings, remove the bottom plugs so as to let the oil drain and with the plugs out just turn the engine over to pump out the last of the offending oil. In with the plugs and close the cowling and start the engine soon as possible afterwards.

If you were on your own it could be a bit of a hard job so you soon learnt never to leave the engines stationary for too long and it was best to turn them over on the starter once a day to try and pump any oil out into the exhaust before the amount got too large.



Quoting JetMech (Reply 5):
JT3-D / B707. Apparently, there was a conveyor belt inside the pylon that moved the coal dust down from the wing to the engine .

You are absolutly correct about the coal conveyor belt as that was one of the sootest engines I have seen and even to this day some 45 years later I still have a black soot mark where I cut my hand removing a cowling from the engine . However the drippy old radials used to look for a person with a white shirt on an no matter how careful you were some how or other the wind would get a drop onto that shirt, and the mark woul never come out

littlevc10


User currently offlineJetMech From Australia, joined Mar 2006, 2684 posts, RR: 53
Reply 7, posted (5 years 3 weeks 4 days 15 hours ago) and read 9502 times:



Quoting VC10 (Reply 6):
Pulling the prop the wrong way only puts the offending oil in the intake manifold from were it goes back into the cylinder when you try to start.

I see. It makes sense that you would not want that oil to drain into the inlet manifold.

Quoting VC10 (Reply 6):
I still have a black soot mark where I cut my hand removing a cowling from the engine .

Fixing planes leaves its mark on you doesn't it? For my part, I've been left with sensitisation to certain chemicals and no doubt, a small amount of industrial deafness.

Quoting VC10 (Reply 6):
no matter how careful you were some how or other the wind would get a drop onto that shirt,

I found the same thing with sealant.

Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineTdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 8, posted (5 years 3 weeks 4 days 13 hours ago) and read 9491 times:



Quoting JetMech (Reply 5):
Would it make a difference which way you hand propped the engine?

If you hand prop in the right direction, don't you run the risk of accidentally starting it?

Tom.


User currently offlineKELPkid From United States of America, joined Nov 2005, 6343 posts, RR: 3
Reply 9, posted (5 years 3 weeks 4 days 4 hours ago) and read 9427 times:



Quoting Tdscanuck (Reply 8):
If you hand prop in the right direction, don't you run the risk of accidentally starting it?

Tom.

Not really. If you've ever seen a radial start up, you know it's a miracle when two or three cylinders fire, and then you have to coax the rest to act in agreement that the engine should be in a state called "started"  Wink That said, yeah, there's the risk of one or two cylinders firing if one of the magnetos has a broken p-lead (magnetos are always "live" unless grounded-every flight instructor I ever had always taught me to treat any propeller as if it would start if it were pulled through in the right direction).

Quoting VC10 (Reply 3):
That schematic of the oil system is great except it shows all the oil returning via the scavenge system to the external oil tank, however with these old engines we know that a fair proportion of the oil was either burnt or leaked over the side to become the aircraft's anti corrosion treatment On the Wright 3350 [Connie fame] normal oil consumption could be 1 US gal per hour with a max allowable of 5 US gals an hour so the external oil tank had to be large and on the 749 was 55 US gals for each engine. On the 1049 they had a slightly smaller oil tank for each engine , but then they had a large central oil tank from which they could transfer oil to any engine in flight.

Indeed. I always marveled when I was a lineboy that flat engine oil was sold by the U.S. quart (same as automotive oil here-slightly less than a liter), and radial engine oil was sold by the gallon. Even a relatively "small" radial (like the one in a Stearman or Beech Staggerwing or Cessna 195) took oil in quantities that would blow the mind of a pilot of horizontally-opposed engines.

I washed more grease off of the bellies of radial-powered birds than anything else  Wink



Celebrating the birth of KELPkidJR on August 5, 2009 :-)
User currently offlineVirginFlyer From New Zealand, joined Sep 2000, 4537 posts, RR: 41
Reply 10, posted (5 years 3 weeks 3 days 20 hours ago) and read 9388 times:



Quoting VC10 (Reply 6):
However the drippy old radials used to look for a person with a white shirt on an no matter how careful you were some how or other the wind would get a drop onto that shirt, and the mark woul never come out

There was a C-54 parked at the airport I used to work at, and they'd fire it up periodically to keep the engines running. Was a fine sight seeing the oil smoke come off them as they struggled to life. When they weren't running, they had big trays under the engines to catch the oil and prevent it all leaking into the ground (which was already fairly oily). Anyway, there are a group of school kids at one of the flying schools, doing a school holiday course. An instructor takes them over to look at the C-54. One of them goes up to the engine, asks "what's this" and before anyone can stop him, gives a good tug on the drip tray with obvious results. I imagine his mother was less than impressed that evening...

V/F



"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh
User currently offlineNomadd22 From United States of America, joined Feb 2008, 1828 posts, RR: 0
Reply 11, posted (5 years 3 weeks 3 days 18 hours ago) and read 9370 times:

If the engine was locked by one cylinder on it's way up on the compression stroke then wouldn't turning it backward free it up since the piston going down instead of up would suck the valves open and allow it to move? Then on it's trip back up while still going backward, the intake valve would open. You'd get oil in the intake, but you hopefully wouldn't suck all of it back into the cylinder on the first stroke, allowing you to get it going in the right direction again.

[Edited 2009-06-29 08:34:35]


Andy Goetsch
User currently offlineVC10 From United Kingdom, joined Nov 2001, 1406 posts, RR: 16
Reply 12, posted (5 years 3 weeks 3 days 16 hours ago) and read 9337 times:

Nomadd,

What you suggest might work, but if it does lock up again when you try to start you could bend that connecting rod at the worst or have to get out and drain just as you are ready to go at the least.

The aircraft that I crewed on had a clutch between the starter and the engine, and this would slip as soon a cylinder locked up. On the initial start [ or pre- start] of the day we would turn the engine 12 blades [to ensure no cylinder would lock up] prior to trying to start the thing by switching on the mag. The rest of the sequence was PFM, " Pure F-------g Magic"

littlevc10


User currently offlineJetstar From United States of America, joined May 2003, 1638 posts, RR: 10
Reply 13, posted (5 years 3 weeks 3 days 11 hours ago) and read 9305 times:
Support Airliners.net - become a First Class Member!

All the radial engines that I worked on were dry sump engines. On the R-4360-59B engines that I worked on in my Air Force KC/C-97 days, each engine had a 27 gallon engine oil tank mounted in the QEC just behind the engine, (the Quick Engine Change is where the engine is mounted too and has all the hoses and plumbing and all the other accessories that are not directly mounted on the engine, the QEC is what is bolted to the airframe, the engine is mounted to the QEC). The engine oil tank shared the same outer housing as the turbocharger oil tank, which held if I remember correctly 3 gallons of lighter turbo oil. If the FE over serviced the engine oil tank and the turbo oil tank was not full of oil, the turbo oil tank would collapse.

On the FE’s panel was an engine oil quantity gauge with a rotary switch for each engine, in the lower forward cargo compartment was a built in 55 gallon oil tank and the FE could top off the individual engine oil tanks in flight. A low time R-4360 could normally use 1 to 2 gallons and hour of oil, older engines could use over 3 gallons an hour.

The belly oil tank was serviceable in flight and on long trips extra oil was carried on board and the belly tank was often serviced in flight. Some units even modified their airplanes and installed a 55 gallon drum with an electric pump so they could easily top off the belly tank.

The KC/C-97 had over 10 hours range, easily flew from the west coast to Hawaii, so on a long flight sometimes oil was the limiting factor, if the airplane had 4 higher time engines they had to make sure they had enough extra oil on board.

On our base, we had a 500 gallon oil truck to service the oil tanks on the airplanes, the engines used SAE 50, 100 weight oil so in the cold winter days engine pre-heating was required. The oil truck was filled from 55 gallon oil drums lifted up using a fork lift and in the winter the oil was like molasses.

Before engine start we would walk the prop through in the direction of rotation 12 blades to make sure none of the lower cylinders had any hydraulic lock. On cold winter days it sometimes took 2 people to walk the prop through, fortunately the engines were low enough to the ground to no ladders were needed.

One funny story, I was on board a flight as an additional crew member when we flew to a civilian airport in Florida to pick up a high level General. The belly oil tank needed to be topped off so we asked the lineman of they had gallon cans of oil, we needed 55 gallons. He said that all they carried was quart cans, so he came back with 10 cases of engine oil, 24 cans to a case and in those days using an oil spout topped the oil tank, one can at a time. After emptying almost 200 cans he thought he was done, then the FE topped off the engine oil tanks with the internal pumping system and used up almost half the oil in the belly tank. The FE then told the lineman he needed to get another 5 cases and the look on this poor lineman’s face was incredible. The FE then told the lineman he was kidding, we had enough oil to get back to our home base.

Unfortunately for the lineman, this oil and the fuel was charged to a military credit card so there was no way we could give him a tip, which he so well deserved.

JetStar


Top Of Page
Forum Index

Reply To This Topic How Does The Oiling System On Radials Work?
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
How Does The Air-Conditioning System Work? posted Wed Jun 20 2001 04:06:04 by United Airline
How Does The Tcas Work? posted Mon Feb 2 2004 13:41:31 by Sfilipowicz
How Does The Earthquake In China Affect ATC? posted Mon May 12 2008 11:06:26 by Ryu2
Why Does The Captain Sit On The Left? posted Fri Mar 18 2005 19:31:16 by JAM747
How Does The NavData Update If A/c Is Airborne? posted Thu Oct 31 2002 21:56:38 by BA777
Information On The Brake System On An Aircraft posted Sat Apr 6 2002 14:50:19 by SOHK
How Does The TU-154 Navigate? posted Thu Apr 4 2002 00:56:09 by AdamHarvard
Does The ND Of A Real Plane Work Like The In Fs? posted Mon Nov 6 2000 16:39:20 by Sushka
What Does The Nav Function On The AP Do? posted Tue Oct 24 2000 00:17:36 by TWA717_200
How Long Does It Take To Be In The Cass System posted Sun Dec 9 2007 12:30:21 by Tuhlhorn
How Does The Airmap / Airshow Work? posted Sat Apr 10 2010 03:25:07 by Thai744
How Does The Tcas Work? posted Mon Feb 2 2004 13:41:31 by Sfilipowicz
Does The Main Gear On A 747 Turn? posted Tue Jun 14 2011 09:28:28 by axelesgg
How Does The Earthquake In China Affect ATC? posted Mon May 12 2008 11:06:26 by Ryu2
Why Does The Captain Sit On The Left? posted Fri Mar 18 2005 19:31:16 by JAM747
How Does The NavData Update If A/c Is Airborne? posted Thu Oct 31 2002 21:56:38 by BA777
Information On The Brake System On An Aircraft posted Sat Apr 6 2002 14:50:19 by SOHK
How Does The TU-154 Navigate? posted Thu Apr 4 2002 00:56:09 by AdamHarvard

Sponsor Message:
Printer friendly format