Propeller Stories
Feather Four
by Tony Vasko
The Curtiss Electric Props were relatively rare in American commercial service
although fairly common on some models of the Constellation used by foreign
airlines. Oddly, for I believe they were the only ones so fitted, United used
them on their Boeing B.377 Stratocruisers. BOAC procured them from United in the
mid-50's and among their immediate modifications was removal of the Curtiss
Electric props and substitution of the more familiar oil operated Hamilton
Standards. However, the Stratocruiser's props seemed to be snakebit no matter
what type and I will drop that issue.
Seaboard and Western Airlines had selected the Curtiss props for their Super
Constellations for reasons I never learned. The Curtiss props were more fun to
operate than the Hamilton props as you had very direct control of blade pitch. A
prop control switch located on the flight engineers panel was fitted for each
engine. The switch could be toggled to: INCREASE (increase pitch),
DECREASE (decrease pitch), OFF (essentially fixed pitch), and AUTOMATIC
(where it responded to the master motors commands). There was a guarded FEATHER
switch, which activated one of two voltage boosters under the cockpit. This
motor-generator raised the propeller operating power to 65 Volts instead of the
normal 28 Volts. This higher voltage speeded the prop's motion toward feather or
reverse as selected. There was a device carried in the engineer's desk that
looked like a set of brass knuckles. Four hollow pegs protruded that slipped
over the four prop control switches. It gave the flight engineer the ability to
move all four switches at once.
To complete the
system there was a master motor with four prop contactors fitted. The master
motor was electrically driven and its RPM was controlled by a master prop
control lever. A tach indicator on the FE panel indicated the RPM of the master
motor. The FE set the master motor RPM to its desired point, threw all four prop
switches to AUTO and listened to a lot of clicking and clacking of contactors.
Each contactor was synchronously driven by a prop alternator on its respective
engine. If contactor and master motor RPM did not coincide, the contactors were
displaced to activate the prop motor and the pitch (and thereby the RPM) was
adjusted. It was a mechanical system operating electrical contacts. It was noisy
but it worked.
One minor item might be noted. The prop control switches on BOTH the
Curtiss and Hamilton Standard props had an INCREASE and a DECREASE position.
Curtiss however referred to the pitch, Hamilton to the RPM. In
other words, the two systems had markings that said the same thing but
were directly opposite in effect.
We ran
a Seaboard Connie one midnight shift after a maintenance check. I rode the
brakes in the Captain's seat. Down below on the ramp, acting as fire guard was
Lex Kutter. He had injured his knee and so could only hobble. He leaned on the
big CO2 extinguisher and watched the engines crank. The fuel injected
R-3350's were less likely to catch fire than the carbureted types so he stood at
ease. The run commenced.
Riding brakes on a Connie during runup is dull and boring. All the controls
and most of the engine indicators are located on the FE panel. The airplane
rocks and the sound of the engines is soporific. The run ground on for several
hours as we had to pressurize, a slow and tedious process on the Connie. Finally
the high moments were reached with the mag and prop checks. My numbed brain
(midnight shift) only registered the highlights. The Seaboard Airlines
maintenance rep was in the cramped cockpit behind the Lead mechanic who was at
the FE panel. The rep was reading the steps to follow from the runup form and we
launched into exercising the Curtiss props. We ran at high power and the knuckle
buster was used to toggle all four props to INCREASE. The airplane bucked as the
prop pitch increased and the engines loaded up under the increased strain. Now
DECREASE and things lightened up. Down below I could dimly see Lex Kutter still
leaning on the fire extinguisher nursing his sore knee.
Now came the command, "feather four". This is somewhat ambiguous as the
"four" may be defined in two ways: "four" referring to the engine position OR
"four" referring to the number of engines installed. It is not truly ambiguous
however as the intent was to feather check the four engines BUT, one at a
time. This was midnight shift however and the lead mechanic, brain in slow
gear, reached out and raised the guards on all four feather switches and
indeed "feathered four!"*
The voltage boosters did their work. The 65 volts drove the props toward
feather. I dully realized the airplane was lurching and bouncing in a most
peculiar way. I looked out the window and saw the entire ramp was brilliantly
lit. I vaguely wondered what could be lighting up the ramp? It was easy! It was
us!
Under the load of the feathered props the four engines slowed to 200 RPM and
lumped over, protesting under the abuse and spouting raw fuel out the exhaust
hoods and every exhaust joint. It burned very brightly. In the light I could see
Lex Kutter with the fire extinguisher. His mouth was agape and he futilely moved
the wheeled bottle back and forth trying to decide which fire to attack. The
Seaboard rep was screaming at the Lead who now was thoroughly flustered. In
desperation he threw the four prop switches to AUTOMATIC but the master motor
wasn't running so the props stayed in feather.
The engine fire bell began to ring and soon all four engine Zone 1 fire
lights were brightly lit. The noise further addled the lead mechanic's wits. He
grabbed the knuckle-buster and toggled all four prop switches to INCREASE. The
rep began to pound on the lead mechanic's back driving him down on top of the
prop controls. It was getting serious as the engines continued to lump over
spouting fuel and flame. The FAA control tower saw the fire and dispatched the
crash trucks. The fourth person in the cockpit was Old Jim Lerwick. He was an
Inspector who accompanied us on the run to verify its proper completion. He had
been dozing on the 260 step and now came to life (The Constellation cockpit's
floor is lower than the cabin floor. The cockpit door is at aircraft station 260
and the step-down was known as the 260 step)
He pushed the frenzied rep off the lead mechanic, pulled the lead off the
controls and calmly toggled the four props to DECREASE while he added power. The
engines responded as the prop pitch decreased, the RPM went up and the fires
were blown out. Just then the crash trucks arrived having broken through the
taxi gates to get onto the Lockheed property.
We were the perfect picture of a Connie on runup as they pulled up. The four
engines were at power and the PRT exhausts spouted long blue flames just like
normal. The trucks stood poised but puzzled and then left after Lex assured them
there was no problem. Their Lieutenant stayed till the run was complete.
"No problem!" the lead mechanic explained. "The tower must have panicked over
a little torching".
We thoroughly inspected the engines and aircraft. No damage. No problem.
Feather "four" indeed!
*The correct procedure during a "feather" check was to feather one engine at
a time. You toggled the guarded feather switch and watched to see that the RPM
decreased rapidly indicating the prop was indeed feathering. You then returned
the feather switch to normal long before it actually reached feather and toggled
the control switch to "decrease" pitch and went back to normal operation. You
didn't actually allow the engine to reach full feather. You could, and I have
seen the engine run in feather, throttle open quite a bit and mixture leaned
back to prevent flooding. If you didn't add power the engine could stall and if
you didn't lean there was excess fuel with the results given above.
Hal Davey replies:
"I love that story; I had a similar experience in 1966. I was at that time a 707
simulator operator at LAX for American Airlines. I was working the late shift
and bored to tears. The check captain, Stan Clark, a crusty old ex-B-26 Marauder
veteran, was in the right seat giving a captain training before a check ride the
next day. We had a lousy intercom system in the old simulator. The captain was
struggling but doing OK. We were executing an ILS to 100 feet. On the missed
approach at 100 feet, Stan calls back and says "Kill two" Half asleep, I killed
numbers one AND two! The poor captain jams the rudder to the stop and is
sweating bullets, but manages somehow to make it to clean up OK. Stan just turns
around and looks at me with a smirk and waves his stoggie at me. The captain
passed."
What Are These Funny Red Buttons For?
by Tony Vasko
Seaboard and Western, later Seaboard World Airlines, operated four L-1049D
Constellation aircraft. These Connies were the only "D" models made and were
also were nearly unique among American operated L-1049 in that they had Curtiss
Electric propellers rather than the almost universal Hamilton Standard
Hydromatic propellers (although their later "H" models also had Curtiss). The
Curtiss electric props had good and bad points. Good in that you could change
pitch without running the engine or using the Hamilton's required feathering
pump. They were certainly cleaner to maintain as they did not use the engine oil
to activate the pitch change mechanism and never, but never required desludging
of the dome. Grease for the bull and bevel gears, brush blocks for transferring
the electric power from a fixed engine nose case to a rotating propeller and
checking and replacing the prop brakes were the main worry but the hollow steel
blades and the composition blade cuffs made them expensive to overhaul.
British Overseas Airways Corporation (BOAC) contracted with Seaboard to
operate the New York to Bermuda passenger flights for them. BOAC was short of
equipment as the Comets and Britannias were in trouble. The Bermuda run, being
short and well travelled used an all-coach airplane. Seaboard, with nice new
Super Constellations was contacted. The L-1049D's, while primarily cargo planes,
were indeed passenger capable as seats could be installed in floor mounted
tracks. Two lavatories in the rear were marginal for long flights but not for
the Bermuda run. One minor problem was that the curtains that stretched down the
sides covered mostly bare wall for there were only had four windows on each
side.
The passengers were vocal for they did not like staring at a blank wall. They
tore the curtains down as if they could find windows under them. BOAC was upset.
No one had lied or misrepresented anything. They simply hadn't asked.
Nevertheless the word came out. No windows, no contract. Seaboard was faced with
a dilemma. They searched for a Super Connie but they were in demand. They
finally found that CUBANA had an L-1049E-01 available. A slightly higher gross
weight version of the E model it was perfect except for having a standard first
class and tourist configuration instead of the desired all-coach set-up.
Not to worry. The maintenance company I worked for, Lockheed Aircraft Service
International at Idlewild Airport in New York (Now JFK Airport) would do an
interior conversion to all coach and do it in stages with no interruption to the
schedule. The airplane was duly delivered and registered as N1005C. After a
maintenance check it was ready for its initial flight as a Seaboard aircraft..
The crew conducted an extended preflight which seemed to entail a lot of
discussion about the props but finally boarded. The Connie had a crew door on
the right forward fuselage just aft of the Flight Engineer's (FE) panel. When
starting engines, the mechanic would position himself down below it and signal
up to the FE. I stood there waiting to give the engine start signals but instead
got a call from above.
"Could you come up here please?" said the FE.
I retrieved the crew ladder and mounted. The FE looked very confused.
Nowadays, the FAA would require an airline conduct extensive "difference"
training when an "E" model of anything was integrated into a fleet of "D"
models. In the 50's nothing much was apparently required.
"What are these red things?" asked the FE pointing at the feathering buttons.
"Why don't the props work when I move the control switches, I can't hear the
master motor and I don't see a master prop tachometer?"
I rose to the occasion. "This aircraft has Ham Standards, not Curtiss
Electric props. Those are the feather buttons. Push to feather and the light
comes on inside to tell you the button is pushed. The feather pump runs and
feathers the prop and when the pressure builds up enough the button pops out to
tell you it is fully feathered. To unfeather, pull the button until you get RPM
on the engine. There is no voltage booster for feathering or reverse, the
feather pump does the job instead".
"The last airplane I flew with feather buttons was the DC-4 but it didn't
have prop control switches", yawned the Captain.
"No", I responded. "The DC-4 used cables to control the prop governors and
had manual synchronizing. This one is electrically controlled and will
synchronize automatically".
The FE nodded. The Captain looked bored. I continued, "The prop control
switches on this airplane signal the synchronizer box which doesn't make
grinding and clicking noises like a master motor. To set RPM you have to be in
governing range. The props will all follow the prop control lever if each switch
is in the middle position. There is no "off" or fixed pitch position like the
electric props. You can control individual props with their switch".
"That should do it", said the Captain. "Lets get this thing on the gate. I
don't want to blow the first departure".
I left the cockpit and descended the ladder. Pulling it I made twirling
motions to the FE. The big R-3350-DA-3s belched smoke and we waved them out to
taxi the terminal.
NOTE: N1005C, after its flying career, was placed on top of a diner in
Pennsylvania. It is now on display at the AMC Museum painted to represent a C-121C military transport. They used the engines, props, landing gear and rear cargo door from a NC-121K 141292 that was being scrapped at Florence, South Carolina for the restoration since the items had been removed during the restaurant conversion and the aircraft never had a cargodoor.
N1005C History
N1005C images in the many color schemes it carried throughout the years.
Additional Musings
by Tony Vasko
I have on theory on why Curtiss props were
unpopular. I think it was mainly because you had to "operate" them. Ham Standard
control was much simpler and unless you reversed it or feathered it you were
between the governors high and low RPM settings and couldn't escape. Basically,
a Ham was always in AUTO. You couldn't overspeed it as the governor prevented
that.
Ahh, but with the Curtiss you could! Once out
of AUTO, you had an adjustable prop that stayed where it was put. On the old
systems with the governors on the engine, if you went to AUTO you went to where
the governor was set. On aircraft like the Connies and DC-6 with synchronizing,
the Master Motor had to be running. If it wasn't, you went to AUTO and it stayed
where it was. No signals to change RPM.
In short, the Curtiss gave you too much
control. A pal of mine here at Piedmont Triad International airport, Ronnie
Macklin was the Director of Quality for Piedmont Airlines. He was, very briefly,
Jimmy Dolittle’s crew chief in North Africa on B-25s. But more to this point, he
was in Martin B-26s before that when they were very new. He recounted the
run-down battery theory to me years ago before I saw it anywhere else. He swears
that the main trouble was an undernourished generator system and people starting
and checking the aircraft out on battery power and running it down. On takeoff,
props in AUTO and full DECREASE (pitch), the aircraft would accelerate and the
prop revs would start to increase due to airspeed picking up. The governor would
signal overspeed, contacts closed and the electric power went two places, to the
brake release and to the motor to increase the pitch. With a weak battery, the
brake would release but the motor wasn't getting juice enough to overcome
centrifugal twisting moment. The prop would go flatter and RPMs would wind off
the clock. "One a day in Tampa Bay". Actually, I don't think Ronnie was in
Tampa, it was before that but the result was still the same. That was weakness
that the Ham Standard never had.
I seem to recall that late in the use of Ham
Standard props on Connies they added a pitch lock in the distributor valve. That
would lock the prop at some increment of overspeed which would occur only if the
dome seal blew or the nose case had a reduction gear failure. No oil pressure
and maybe the oil passages were kaput so no feather either. There were
flyweights inside that extend out and locked things up. You were stuck with the
pitch the prop was at but that was far better than it going flat, which it
otherwise would.
Berge Jermakian replies:
I read Tony Vasko's mussing on the
Curtiss Electric Prop. It brought back memories of my time working line
maintenance at KLM (Idlewild International).
KLM had Curtiss props on all their
Connies from the O49 thought the 1049G. KLM liked the Curtiss for the additional
control, plus the props required less maintenance and were cleaner to work on.
The Hamilton Standards needed to be regularly de-sludgged by removing and
dismantling the dome, then scraping out the built-up hard sludge in the dome.
With the Curtiss props, occasional line problems were usually fixed by
adjustment of the motor brake.
Removing the dome from the engine
while on the airplane sometimes got a bit exciting. That was when the small
expansion plug (looked much like a miniature of the critter you find on engine
water jackets) that kept the hundred or so tiny ball bearings the dome nut rode
on. If you were unaware of this plug, or were weren't paying attention, or it
was loose and fell out while you were unscrewing the nut, then quick as a flash
all the bearings poured out like water and bounced all over the floor. You
couldn't see the plug till you had backed out the nut a ways. By then your
attention was on supporting the loosened dome. Fortunately our floor was kept
clean as the several mechanics working on the prop, plus anyone else in the
vicinity were on all fours hunting up the errant ball bearings. We did manage to
find them all.
Another Missing Bearing Story
On the Berlin Airlift Boeing C-97G I'm helping restore, I noticed the crew was having a problem getting the propeller lifting fixture on the prop that had to be removed. I also noticed a trail of small ball bearings on the ground leading to the engine from which they were to remove the propeller. Having seen this story before, I went over to see what was going on. The retaining nut, which is the same as on a prop dome, was cocked and would not engage the threads. I had the men remove the tool and upon checking, it was found to be missing most of its ball bearings due to a lost plug. We found enough dropped bearings to place in the ring and made a plug with tape so remain correctly orientated. After the prop was removed I set about to repair the lifting fixture. The bearings (144) were easy to find, but the plug was another issue. The plug is small, about 3/8 " diameter and I couldn't find any vendors that sold Welsh plus that small. In my search I learned how the plug got its name. There was an early 1900s car manufacturer called Welsh Bros. Motor Co. In early engines, the holes left in casting water jackets of engine blocks were closed with a threaded plug. The Welsh Brothers devised a concave plug that we are all familiar with today that could be installed in the place of the threaded plug. This reduced the cost of making blocks. The company, H D Hubbard Spring Co. who made the plugs for the brothers makes plugs of all sizes and materials to this day and still calls them Welsh Plugs. Thank you to Hubbard sales, who were kind enough to send me a few as samples so I could fix our prop lifting fixture dome retaining nut.
More Thoughts on Props
by Tony Vasko
I
read Berge Jermakian’s recollections regarding the Hamilton Standard props with
great amusement. Exactly the same thing happened to me. As he says, the prop
dome is attached to the hub by means of a retaining nut which is retained on the
dome by means of lots of ball bearings riding in internal grooves machined in
the dome and the retaining nut. They were fed in there through a hole on the nut
which was sealed, as Berge says, with an expansion plug, I think they were
called Welch plugs. Boy would those ball bearings pour out if the plug came
loose. Then there was Hell to pay.
Not so bad if
it was a prop change as overhaul could take care of it but usually it wasn’t. If
it was only being pulled for a dome desludge or an engine change with the old
prop being reused, you had to find all of the little bitty balls that came out.
Usually too, there were always a few that remained jammed in the nut by the
weight of the dome which was quite heavy. They had to come out too so you could
count them. You could find the required number of balls in the Illustrated Parts
Catalog (IPC) so it was a matter of finding all the spilled ones and getting the
rest out of the dome nut and then counting them up. I know we couldn’t and ended
up robbing an unserviceable removed prop dome to make up the shortfall. Finding
ball bearings out on an asphalt ramp at night was not easy.
Desludging
domes was a nasty task. Aside from having to remove the prop dome thereby
releasing several quarts of thick, blackened oil you had to carry it down the
stand and then hump it into the cleaning shop. You took the dome shell off the
stationary cam and revealed a thick, oil covered mass of sludge. The prop, of
course, spins and nicely centrifuges the sludge from the oil. Some engines were
notorious sludge makers, like the BA version of the R-3350 used on the Lockheed
049 Connies, but they all made plenty of it. The sludge was like thickened
modeling clay but was composed of decomposed oil, combustion products and lead
ends from the fuel. It had to be chiseled out by the handful and all the
surfaces scraped clean and then the whole assembly washed with mineral spirits (Varsol).
It was a filthy job and you could tell how you stood with the Lead Mechanic if
you got assigned to it a lot.
Berge is right
about the Curtiss Electrics being cleaner. Their hub was filled with grease but
since it never mixed with the engine oil it was relatively clean. It was a
regular thing to measure the brake pad on the end of the motor. I replaced a lot
of them as it was a critical element. The brushes transferred the electric power
from the stationary nose case to the slip rings on the prop. They were mounted
in a brush block that was easily, but very carefully removed. Brushes were very
brittle, wore down, sometimes stuck and the carbon bits that wore off had to be
washed away regularly. It was not nearly as bad as desludging a dome though.
The steel
blades usually found on Curtiss props stood up pretty well from a line
maintenance standpoint. They didn’t nick as easily as aluminum blades but also
were not as tolerant of damage. Aluminum props were more easily damaged but you
could dress damage out with files and emery paper as the limits were quite
large. The Ham Standard steel blades originally used on the Boeing 377
Stratocruisers were a disaster and were replaced by aluminum blades.
The
Aeroproducts props used on the Lockheed Electras had steel blades. When I came
to Eastern as a mechanic in 1964 I worked phase checks on them at JFK. I was put
on the job of cutting inspection windows in the blade cuffs. Using a template to
accurately locate the position and shape, I marked the location on the backside
of the cuff. I then cut through the outer covering into the foam filling. I then
carefully chiseled a tapered square hole down to the blade shank. It had to be
cleaned of paint and primer. This allowed inspection for a crack in the shank. I
had to coat the foam and seal it to keep the elements out.
I always
wondered why Curtiss and Aeroproducts went away. Curtiss apparently was just a
prime example of beancounters triumphing over engineering. They certainly had a
good product that seemed to be made to order for the turboprop engine.
Aeroproducts had the advantage of being associated with the company that made
the engine they were fitted to. Yet both faded away. It seemed though that
Hamilton Standard was in it for the long haul and still goes on.
One final word,
the Hamilton Standard governors fitted on the piston engines were actually
Woodward governors. You could see their nameplate on the units. Woodward is an
old line company, still very much in business but one that started life building
governing devices for waterwheels back when only birds, bats and a few fish were
flying.
The Curtiss Electric Props were relatively rare in American commercial service
although fairly common on some models of the Constellation used by foreign
airlines. Oddly, for I believe they were the only ones so fitted, United used
them on their Boeing B.377 Stratocruisers. BOAC procured them from United in the
mid-50's and among their immediate modifications was removal of the Curtiss
Electric props and substitution of the more familiar oil operated Hamilton
Standards. However, the Stratocruiser's props seemed to be snakebit no matter
what type and I will drop that issue.
