Radial piston engine oil leaks, DC-4 thru DC-7 and Constellations
 

Any offers on why these engines leaked so much? I'm talking about the copious oil you would always see over the wings of all the Douglas airplanes from DC-4 to DC-7 and the Constellations.

I think this was the reason Delta got fed up and painted dark blue a large swathe of wing behind each of the 4 engines cowlings to hide the oil.

In actual fact, the amount of oil actually leaked was quite small, as just a small bit looks to the casual observer, quite a lot more.
The airflow spreads a small amount out quite a lot so it looks much greater.

By far, the greatest, was oil consumption.
The CurtisWright turbocompound engine, for example, used on the DC-7 consumed (burned) at least one half US gallon, per hour, per engine.
The limit (generally) was two US gallons/hour/engine.

And yes, gallons is correct...not pints, quarts or liters.

Just the nature of the beast. Had to have all that oil for lubrication and cooling and they (R-2800s & R-3350s, etc.) were not tight-fitting engines. That's why the oil tanks were so huge. 56 gallons as I remember. The 'G' Connie I flew could not carry a full load of fuel because the oil capacity was not large enough. A limitation (fuel/oil ratio) that may no longer exist; I don't know. It only burned about 5 gallons a hour!

Since you have such large pieces of metal heating up at different rates the clearances are fairly large which lets lots of oil loose.

DC-ATE - The ratios are still in part 25 if anyone wants to design a new large piston engine. Thirty to one without a tranfer system, 40 to 1 if you can transfer oil. Flew some converted T-29s that had to have an aux oil tank installed because the Air Force had larger fuel tanks than the regular 240.

Many long range aircraft had aux oil tanks for transfer to the engines. The L-1049 Super Connie had a 67-gallon bag tank in the port wing root - The WV-2/EC-121 radar Connies, because of additional fuel, had a second aux oil tank in the starboard wing root. These tanks and lines had electric heat so the stuff would flow when cold. The Douglas types with aux oil thinned it with gasoline so it would flow.

Some engines types were notorious oil leakers - the R-3350 BA series on the L-049/L149 Connies was one such, probably the worst engine ever on an airliner. Had old type hose and clamp seals on the pushrod housings (36 of them) which leaked all the time. Lots of connections for rocker box drains that leaked. In fact if you saw a really clean area on a BA engine, you immediately suspected an fuel injection line leak. Later models (BD, CA, DA, EA) were much better so far as leakage goes.

MarkerInbound -
I sure don't see that happening any time soon, but it'd be nice.:8

I wish people wouldn't refer to the Wright R3350 as a Curtis Wright machination!!

JO

Used to get a regular PAA DC7C daytime layover at my first aviation base. First order of business after chocks in was to put drip trays under all the engines and small collector trays that clipped on to some of the engine drains to keep the airport authority happy as they did not like the black gold all over their precious ramp. During the layover cleaners would wash down the upper wing surfaces behind the engines to remove the oil. There was even an oil slick on the tailplane from the inboard engines.
On start up later in the day the engines usually spat a good dollop of oil out the exhaust on to the wing straight away kinda ruining the cleaners efforts.
I once asked the PAA guys about the size of the oil tank on the R3350 turbo compounds and oil consumption and was told it held 56 gallons and that they didn't worry until consumption reached 4 gallons an hour. If it reached 6 gallons an hour with no obvious leak the engine was removed.

Why do the engines leak so much? The problem starts when the engine stops leaking. If a radial engine stops leaking, then it's out of oil, and that's bad.

When pushrod tube seals are clamped in place using band clamps over rubber hoses, when rocker box through-bolts are sealed with o-rings held against bolts with loose enough tension to only require castelated nuts, when there's no end of parts with the clearance to pass oil, when oil congregates in the lower part of the engine by virtue of gravity and design and gets blown out exhausts on start up...you're going to find oil dripping from the engine.

I've spent a reasonable amount of time piloting radial engine airplanes, and a lot more working on them. Whomever thought up the idea of white shirts for pilots around airplanes was an idiot. Especially in times of radial engines.

In motors like the R2600, typical consumption runs about three gallons an hour. Sometimes more, sometimes less. Some powerplants leak or burn less than others, and the type of operation has a lot to do with it, too.

Suffice it to say that when taking on fuel, nearly always one endevors to fill it up with oil, too. We often operated for three or four hours before fueling, and would end up putting in 40 to 60 gallons of oil while refueling.

Yup.....fill her up with oil and check the fuel!:8

So they used more oil than a 2 stroke .... multigrade 20-60 ?

wonder what the ratio leak:burn was !

Is the aviation gasoline available today still the same formula as used in the 50/60s? Sweet smell I recall much more aromatic than car gasoline - my mother used to tell me not to breath it when I wondered around underneath a DC-3 looking and touching everything until one day I burnt my fingers on very hot break disks.

Oh ...and fabric elevators and rudder always puzzled me why fabric was used?

Worst oil leak I ever saw was on a RAAF Convair 440 Metropolitan when during the take off, the main oil line to the oil cooler split asunder and we lost the full contents of 35 gallons very quickly which resulted in a runaway propeller at 800 feet. Fortunately the oil tank had a stand-pipe with just enough to feather the prop. The oil leak soaked the wheel well, the brake units and all over the elevator area.

If I remember well, DC4 had a capacity of 20 USG per engine and a 50 USG tank for in flight transfer, while the DC6-B had respectively 40 USG per engine and a 26 USG oil tank ..... and great to fly ... these were the days!!!

MP

B377

We'd do straight 50 weight oil in the winter and 60 weight in the summer.

There used to be at least 5 grades of av gas -

80-87 was red
91-96 was blue
100-130 was green
108-135 was brown
115-145 was purple

And I seem to recall there was yellow down in the 70-78 range.

Now about all you find is 100LL and 80 UL, totally different stuff.

You touched a disk brake on a Three? All I ever had were drums and expander tubes.

Fabric is lighter.

Yup, still using about a gallon an hour! These days with turnarounds measured in days or weeks we get plenty of time to chase oil leaks. Done properly, this results in no more oil than you can clean away with a rag after flight.

We've recently used W100 and Phillips 66. In any given conditions the latter works best on 2800s for some reason whereas W100 always suited the C47/R1830. No idea.

BTW, new DC-6 forum over at www.thedc6.com/forum by the Air Atlantique people. Not much to see unless you register, but it's new so probably waiting for input from us lot.

Recall the tongue in cheek advice if you could jump over the puddle of oil on a preflight it wasn't a leak.

Leaky Radials
 

Don't think I ever encountered an engine which came even close to leaking as much oil as a Bristol Hercules Sleeve Valve. On manufacture joints were metal to metal, which was fine until some boofhead split components by driving a screwdriver between the surfaces. Even buckets full of Hermatite sealer could not keep the oil inside the engine. First action by the groundies when the aircraft stopped on the ramp was drain bucket under the nacelle drain tube and then the chocks in place. With sleeve valves to be lubricated plenty of oil also made its way out the exhaust ports. We jokingly called them "High powered Oil Pumps"

Radial Engine Oil Leaks
 

Oil leaks were bad on small radials as well. Flew a 600HP P and W around
PNG for a couple of years, It had a 9 gallon oil tank, used about .5 of a
gallon per hour. Had a close one with oil loss [DHC3]. Had a short flight of
15 min, 10 min into flight oil poured up windscreen, oil pressure a little low
but steady, landed ok. jumped out to find a couple of gallons on the ground.
Dipped the tank , only under .5 of gallon in tank. Couple of minutes more
flight and I would have been not here today. The problem was the HP
pitch control pump had been overhauled some 50 hours before hand and
the pressure adjustment bolt locknut came undone. Had a couple that
night.

99

MARKERINBOUND
They sure looked like disks to me. Mind you it these were two COLPET DC-3s ( in Colombia) sporting uncommon wheel spats that recieved plenty of TLC from company mechanics .. so had ungraded brakes perhaps? else I am wrong.

Still remember the clicking of the hot engine and exhaust metal after shutting down.

That is an amazing list of gasoline grades had no idea! How would you choose when filling up?

One of the things about having a plane operate for 50-60-70 years is a lot of work can be done on them. The Super DC-3s had disks from Douglas, I guess it wouldn't be too hard to get an STC.

The AFM or Pilot Handbook would tell you what grade to use. You could always go up, just didn't want to use a lower grade than what was approved.

MarkerInbound -

Lower grade fuel was approved in some cases, but you had to operate at reduced power.

I had disc brakes on my old DC-3, I believe it was called the 'Convair Brake Conversion'. On initial application the disc brakes did not seem to slow the aircraft as rapidly as the tube brakes, however, you never had the problem of the brakes fading either.

You can't really tell from this picture, however, I never thought I'd need a picture of the brakes on the DC-3.

http://i28.photobucket.com/albums/c2...6-2007_016.jpg

By the way, we didn't fly it that much and I had a mechanic (engineer) that just loved working on the old gal. He kept the oil leaks to a minimum. We ran the engines at least once a week and flew it once a month, even if it was just around the pattern. Fortunately the owner understood that we couldn't let it sit around and let me fly it when we needed to. It was fun to take to local airshows in the summer.

Sadly she is sitting all but abandon at some airport in California. The last picture of her that was sent to me she was looking in rather poor condition.

Goodyear disc brakes (Part No 9540385 :8) were originally fitted to British European Airways Dakota 3s (or more correctly, Pionairs) around 1955 and most British registered Daks have them as standard.
I'm a mine of useless information...

Here is a link to some lovely photos of DC-3s with what looks to me like disc (disk?) brakes.

http://www.michaelprophet.com/VVC-airport.html

Exmek

I used to park a DC-3 in about that same spot, facing south so the UPS truck could back up to us! The Convair brakes had 3 pads, the Douglas DC-3S brakes had 4. I've seen those things glowing cherry red some nights.

SteveF, I think aviation is just one big trivia contest.

DC3 Brakes
 

"Seen those things glowing cherry red some nights". What used you use the old girl for, "circuit racing"? Or maybe you used to land in a tennis court!

Well that just proves that I did burn my fingers on something pretty hot during my DC-3 walkabouts as a kid.

Below is one or other of the two DC-3s in question behind the lucky pilots that flew it (top pic). Wheel spats can be seen. HK-1503 w/o in 2004, HK-1505 fate unknown to me.

Is draining fuel from the wings (via a valve or something seem to remember) to fill a cigarette lighter common practice? Seen it done.

photo date early - mid 60s , Coveñas

http://www.geocities.com/gabrielmore/tn_Foto187.jpg
http://www.geocities.com/gabrielmore/tn_Foto186.jpg

When you're taxiing for a mile or so with a 30 knot crosswind with one engine at 30 inches and the other at idle to keep it straight you do tend to ride the brakes.

Fill a cigarette lighter? You're not draining enough gas! We keep a few old coke bottles in the back. A converted C-47 has 6 fuel sumps. Working out of a small field, guys would drive right up to the plane to load their kit. I've seen guys sump a tank, walk over to their car and pour the fuel in, walk back to the next sump and repeat. They probably got a gallon of gas a night!

Fair to say that I did not see much oil leaks on these DC3s. They were probably cleaned regularly. Nothing like you see on some 6s and 7s.

With all that gas in wing tanks and sumps 'no smoking' signs had to be taken very seriously.

Like don't try your recently filled cigarette lighter .

AINT SHE A BEauty!!
 

nice one !! :ok:

PW R4360 Wasp major
 

Thanks for all the oil discussion. I'm still working on getting my R4360 running this summer. I've read this engine takes 100wt Mil spec oil and burns 130 octane gas. I'm not sure what size oil tank I will need to do ground running. I don't plan on running it for very long at each start and have been considering not installing an oil cooler. What size oil tank do I need to run the engine for 5 minutes or so at a time?

”two COLPET DC-3s (in Colombia).”
 

Hi,My name is Carl Hearn. I just stumbled upon your 6th March 2009 reference to ”two COLPET DC-3s (in Colombia).” I’m thinking these might be the same two DC-3s owned by the Colombian Petroleum Company, which were primarily used to transport personnel, equipment, and supplies to and from Cucuta, and the company’s oil camps. If so, I rode in the aircraft a number of times during the years 1948-50 when they were flown by pilots named Hightower and Parrish. I also went to school with the pilots’ respective sons, Jimmy and Michael. My dad, Carl Hearn Sr. was employed by COLPET until 1951 when he went to work for Royal Dutch Shell and we moved to Venezuela. I’m guessing the aircraft I traveled in would not have had disk brakes at the time I mention, but it is fun and interesting to read about aircraft that could be the same ones, just updated. It would also be fun and interesting to hear about your connection with these aircraft and the place and time? My email address is [email protected]

This is a beautiful and interesting discussion--- highly informative for a 'jet-age guy':D:D:D

PA

P&W R-985
 

Always got a smile out of the fact that the oil filler cap was in the cockpit between the pilots on the floor of the Dh2 Beaver, and the next time I do a raidal float endorsement, I'll be wearing full length oil proof overalls! great fun tho'!:ok:

Historical fact...the Douglas DC-6B was the absolute least expensive 4-engine piston aircraft to operate (per revenue seat/mile) because of its very reliable Pratt&Whitney R-2800CB16 engines.
And yes, I have about 1000 hours in the 'ole girl...a superb airplane to fly.
No hydraulic boost on any control surface, spring/balance tabs only.
Ahhhh, the good 'ole days.:ok:

The Lockheed Hudson engines (P&W 1830's?) leaked oil over the wheels on the ground. So much in fact, we placed car tyre inner tubes over the top of the wheels on over-night parking. Messy business removing them, too.

Leaking oil Radial Engines
 

It sure stops the rust from forming for awhile

Tmb

AAAaaaarrrrr, the good old days!!
Of PNR oil being more limiting than PNR fuel, and that was with oil transfer systems, aux oil tanks etc.
Tootle pip!!

We parked an old ACE connie on a new bit of concrete
at Cairo.
They had to send a chap out with a bucket of fuel and a
pile of rags when we left the next day.
You could see where we'd been parked for years after.

411A -
You got that right. Got my first Rating on the DC6/7.


Storminnorm -
Ha.....how do you think we found our Gate with the Connies?!?!:}