(Note: Jeff Ethell came to Camarillo CA in Feb 1997 to fly the CAF So Calif Wing Curtiss C-46 "China Doll". Immediately after the flight, he gave the following commentary.)
The C-46 was a big surprise to me. After you fly the DC-3, B-25, and other aircraft considered to be "heavy twins", you appreciate that anyone who flew WWII airplanes probably had to be 18 years old and a weight lifter, because the airplanes are so heavy on the controls. It's not unusual for the B-17 or B-25 to have 100 pounds of control pressure to deal with. Particularly if you lose an engine, you end up wrestling the airplane to the limits of your strength. There's nothing to help you other than muscle power and maybe differential engine power.
It probably wasn't so bad in WWII because those guys were young and fresh out of Cadets. But to those of us who fly them now, they're heavy airplanes. Even though everyone told me that I'd enjoy how the C-46 felt, I was still surprised. From my perspective it was immediately pleasant. The controls never got heavy. The whole time we were flying, even in slow flight and with one engine out, the airplane was very nice to handle. I was surprised at how light an airplane its size was on the controls.
The C-46 was a pre-WWII design, intended to be a pressurized high altitude airliner. It never got there because WWII came along, and it never got its chance to do what it was designed for. But it was available for the massive transportation problem that came with WWII, when we had to move enormous amounts of material, and originally had no Transport Arm to speak of.
Airplanes were inducted into the military. The DC-3 was simply painted green, the seats taken out, and deemed ready to fly as the C-47. There were no self-sealing tanks, no armor plate, no help at all. WWII films taken over Arnheim, and D-Day, show that when a C-47 was hit it became a massive ball of flame. The plane went down immediately. There was no way out; everyone died. It's a terrible thing to watch.
The DC-4 became the C-54 the same way. In fact, United Airlines bought ten of them, but when Pearl Harbor happened they were told "No Delivery". Again, they were painted green and off they went into the Army Air Forces.
Fortunately the C-46 came along, and it had the power to out-perform even those airplanes with four engines. The C-54 out-performed the C-46 to some extent over the Hump, but Hump pilots told me the C-46 was THE airplane you could overload, climb to 20,000 ft (which was mandatory for the first time), go through terrible weather, get to the other side, off-load the equipment and come back. The C-47 couldn't come anywhere close to that. Hump losses were high. We lost well over 700 airplanes, mostly due to weather, while ferrying 650,000 tons of critical war supplies to forces in China. During the peak month of July 1945, there was an average of 1.3 flights across the Hump every minute!
Having flown the C-46 now, I can see what they're talking about. It's a four-engine airplane with two engines! It doesn't need the other two engines because it has two large R-2800s. Everything else had the smaller R-2000s, 1830s, or 1820s. The intention was to give the customer (it turned out to be the Army) a high performance airplane that didn't over-tax the pilot, could be loaded to its limits and would fly … even on one engine.
That was a revolution in the air-transport world. Quite frankly, WWII was a revolution all the way through. It probably advanced airline flying by 10 years because the airline pilot who came out of WWII knew what carburetor icing was, understood the problems of having to go through very tough weather fronts, etc. The C-46 was probably the only airplane until 1944 that could deal with these problems to some degree.
The C-46 comes off the ground like a shot. Of course we were flying it light, but even so, it was off the ground quick and was immediately responsive. Differential engine power was wonderful. There's lots of power in the throttles. You have large engines out there and a move on the throttles gives an immediate response. You don't have that in airplanes of lower horsepower. I didn't fly the C-46 in a cross-wind, so I didn't experience some of the things that could get a pilot in trouble. But it was wonderful throughout the regime I flew.
This pre-WWII airplane was ahead of its day, and held its own throughout the war. Without it there probably wouldn't have been the airlift operation we had; the "Hump" wouldn't have existed. It's certainly a great airplane, and a wonderful piece of history to keep flying. The CAF flies the only two C-46s that are displayed to the public ("China Doll" and "Tinker Belle"). Another 20 or so are still working in Alaska, Canada, and Central America.
(Note: John Deakin flew C-46s for Air America in SE Asia. He's currently a 747 Captain for JAL, and one of the pilots for the CAF So Calif Wing's C-46 "China Doll".)
The one thing the C-46 is really famous for is lousy directional control on the takeoff and landing roll. Its rudder is extremely ineffective at low speeds on the runway, even after the tail is up on takeoff. Even under ideal conditions with the wind right down the runway, or with no wind at all, the airplane might suddenly, for no reason whatsoever, head for the side of the runway rather briskly. If you slam in full rudder to stop it, that rudder is totally ineffective. The only solution is to yank back the opposite throttle to stop the nose. And when the nose starts back, you have to get the throttle back up again to get the beast under control. That particular quirk has bitten more potential C-46 pilots than anything else.
The C-47 doesn't have the same problem. The rudder area on the C-46 is about 30 percent of the vertical surface area, leaving about 70 percent for the vertical stabilizer. The C-47 is reversed, giving it better directional control than the C-46 at low speeds.
Also, the C-46 is a very fat airplane, so when it's moving down the runway the fat fuselage blocks a lot of airflow over the vertical surfaces. The small rudder doesn't get much airflow, which limits its effectiveness. The C-47 has a much narrower fuselage, which allows more air to flow over the vertical surfaces, and it has a larger rudder to boot.
You can easily taxi a C-47 at moderate speed, 10 knots or so, and have rudder control with the free swiveling tail wheel. The C-46 rudder has absolutely no noticeable effect when taxiing.
The C-46 has monstrous ailerons, consequently the adverse yaw effect is much greater than on other airplanes. The result is that if you roll the wheel to the left for a left bank, the nose actually goes to the right if you don't apply a fair amount of rudder to resist it. In most airplanes on a crosswind takeoff, you use the ailerons into the wind to help a little bit. With the C-46 it's absolutely crucial to use the aileron very heavily to roll it into the wind.
It's quite comical to watch when a jet pilot gets into this airplane and doesn't instinctively use the rudder. They're not used to not using the rudder at all, because most of the jet transports have dampers and other mechanisms that let you keep your feet on the floor when your're hand-flying them.
The airplane does a job that no other airplane can do even today. A perfect example is the Everts operation out of Fairbanks AK. They haul 12000-15000 lbs of gasoline and other liquid fuels in 55 gal barrels into and out of 2500 ft gravel strips day after day … an astonishing feat. I'd love to try that for two weeks and really get sharp with the airplane again. Five C-46s fly for Everts, and they're restoring one or two more.
The C-46 has big, fat, soft, low pressure tires, so it operates well off rough, soft, mud, or grass strips. Its footprint is fairly light for a huge airplane. At the time it was built it was the largest twin-engine airplane ever made. It's bigger than the B-17 and B-24 in all dimensions except that the B-24 has a 2 foot longer wingspan:
|Height (ft)||Wing Span (ft)||Length (ft)|
The rudder throw, i.e., the distance the rudder pedals move, is the greatest on any airplane I've ever seen. It's quite difficult to set your seat so you can get full rudder on one pedal and get your other leg out of the way of the control yoke. There's a real trick to it.
I hesitate to say it performs well on one engine, because these days we're spoiled by jets and other high performance airplanes, where the loss of one engine is a no-brainer … it's just a little unbalanced thrust. You have better performance on one engine with any of the modern twins than on both engines with the C-46. Nevertheless, for its era, the C-46 had remarkably good performance on two engines, and pretty good performance on one engine.
It has enough rudder control to handle an engine out, but you have to get it all in there. You have to be aggressive with it. It's got sufficient power on the remaining engine to get around the pattern even with the max gross weight of 48000 lbs on a fairly warm day.
The airplane can do a good three-point landing on short fields. Most people who fly large airplanes are stunned when they see the airspeed indicator sitting at 60-65 kts and it hasn't stalled yet. You make the landing approach at 65 kts, fairly steep, in fact scary steep, and at the bottom when you approach the runway, you yank the power off and haul the nose up and it squats down on three wheels, and you're so slow with so much flap out it slows down very quickly. That's how you get it onto short, rough fields. There aren't many other airplanes that can do that.
In Vietnam we'd go into short, miserable strips surrounded by unfriendly people who enjoyed shooting at airplanes. We'd make a very tight descending spiral with a 45 deg bank turn at 65-70 kts, and make a real tight final turn. Just as the wings rolled level, we'd touch it down at a full stall and slam on the brakes and get it stopped before running off the far end. Only a C-46 will do that with a huge load. The C-47 is good at this also, but can haul only half the weight the C-46 does. A tail wheel airplane is definitely superior to a tricycle gear plane for getting into a short, unimproved strip, and the C-46 really excels at it.
In most airplanes, especially the larger ones, there's a considerable delay between moving a control in the cockpit and having something happen out on the wing, particularly with the throttles or props. With the C-46 you just pop a little throttle on it and you get instant power response. You wouldn't think the big prop would speed up that fast, or that the engine could respond so quickly. When the airplane suddenly veers into one of it's wild excursions, you just pop a little power to it and you get instant response. The most effective directional control on the airplane is differential power. It'll get you out of trouble quicker than any thing else.
I never flew the airplane under icing conditions, but its reputation is excellent for fighting ice. It was used heavily on the DEW Line, where it flew in miserable Arctic conditions, and of course across the Hump where its bad-weather exploits are legendary. I flew C-46s mostly in SE Asia, where the only ice was in our scotch.
It has a good range with regular tanks, which hold 1400 gals. That will take it 10 hrs easily, and if you really go into fuel conservation, you can get 12-13 hrs flight-time out of that much fuel. It will do 150 kts at low power settings and perhaps 125-135 gals/hr. It you really push it, it'll go up to 180 kts at maybe 180 gal/hr. Figure roughly 1 kt per gal per hr, which makes fuel planning fairly simple. At 150 kts, the range is 1500 to 2000 miles … it depends on how slowly you fly and the load on board.
For a WWII era aircraft of its size and type, the C-46 is pretty fast. Even though it looks fat, it's a streamlined airplane. It has a red-line speed of about 230 kts, whereas the "Gooney Bird" is well below 200 kts. At airshows it's impressive to dive down the last 500 ft at full power and go roaring along the runway at red-line speed! Everybody's impressed by how the big, fat, clumsy airplane can really move along.
The C-46 is a stiff wing airplane. Most airplanes are designed with lots of flex in the wing to absorb the turbulence. In theory the wing on this airplane is built like a bridge, and is actually designed not to flex. Don Downie (former Hump pilot and co-author with Jeff Ethell of "Flying the Hump") said "Even in the most violent turbulence, it was impossible to see any flexing of this rigid wing structure. By comparison, the C-47 had a very flexible wing designed to bend under loads. Many times from the cockpit of the C-47, you could see the engine nacelle flex downward as the wing tip flexed upward, much to the consternation of those of us accustomed to the brick-house rigidity of the C-46."
(Note: Ellis Meaker flew C-46s for various commercial airlines in the 1950s, and for Air America from 1965 to 1968. He also flew "China Doll" for many years, retiring recently with 2650 hrs of C-46 flying time.)
I had some Air America and commercial experience with this great workhorse. There were at least 50 non-scheds flying the C-46 in the late 40s-early 50s, carrying passengers and cargo throughout the states. Both Flying Tiger Airlines and Slick Airways freight lines began with surplus C-46s, and operated them even after more modern airplanes became available.
One man could maintain the airplane. It required no more maintenance than the C-47, but could carry twice the load. I liked the big, friendly cockpit, where both pilots could reach everything, unlike a lot of WWII airplanes. There's never a need to put both hands on the controls. Sometimes you might want to in a stiff crosswind when you're putting in max aileron, but normally you can handle everything one-handed.
One reason the airplane can land so slow is that the wing stalls from inboard to the tip. Most aircraft stall at the tip, and give a sharp roll from one side to the other depending on which wing tip stalls first. When the C-46 stalls, it will mush straight down from whatever attitude it's in.
The problem of having insufficient rudder at low speeds is aggravated by the old Hayes expander tube brakes. You can't hold these brakes at fast speeds because they fade exceedingly fast when they get hot, and then the airplane will whip one way or the other. When they made a transport category conversion out of it, they switched to disk brakes, which were a big improvement.
You can land most multi-engine airplanes with one wheel first in a crosswind. But if you try that with the C-46, it's usually going to veer, and you don't know which way until it's happening! So it's better to just touch the wheels simultaneously, even in a strong crosswind. The C-47 lands nicely on one wheel first.
One of my more memorable C-46 moments took place at 5am one morning in 1965 in Saigon, when check pilot Jim Russell and I were in the dark cockpit doing a pre-start checklist. There's a sound-proofing mat on the cockpit sides and overhead. When you test the engine-fire warning system, a red light comes on immediately and a VERY LOUD bell rings. Suddenly 6 or 7 rats came out of the sound-proofing mats and ran around squealing just a foot over our heads! When the bell stopped ringing they disappeared! The check-pilot watched me through the whole thing and said "Don't get excited unless the rats leave the ship!" Our plane carried a lot of rice, and the rats were living on board.
Following WWII the Air Transport Association (ATA) set up regulations and requirements for future transport aircraft. Scheduled airlines wanted to seriously consider the C-46 in their expansion plans. It could carry 45-50 passengers and was available for $20,000 to $25,000 apiece as surplus.
However, one of the requirements was a 250 ft/min rate of climb with gear up if an engine failed immediately after takeoff. The C-46 could barely meet that; the DC-3 couldn't. But since the airlines owned and had to keep operating their DC-3s, they were exempted from this requirement for their remaining years of service. The C-46 was thoroughly tested and squeaked by. In the ATA's summary of their findings, they stated that the C-46 was beyond the capabilities of the average airline Captain! None of the major scheduled airlines ever used the C-46 to haul passengers.
(Note: Merrill Wien flew C-46s for Wien Alaska Airlines in the 50s and 60s, and later for Everts Air Fuel. He currently flies "China Doll", and is an FAA C-46 check pilot.)
The C-46's fine handling and light control pressure on the elevator and rudder were developed after WWII. The original military airplanes were hydraulic controlled and had lots of problems until the hydraulics were removed and spring tabs substituted. Hydraulic ailerons are still used on some aircraft.
The brakes are there to use when needed, but only after ailerons and differential power have proven insufficient. If used properly, the brakes will not be needed until a slow speed is reached on landing and should not be needed on takeoff at all. But pilots used to flying modern aircraft are not used to using ailerons and differential power for directional control. Nose wheel steering does it all.
I flew C-46s for Wien Alaska Airlines in the 50s and 60s, flying cargo and construction materials for the DEW Line and in support of North Slope oil exploration. The airplane performed well on small frozen lakes with one or two feet of soft snow. As we outgrew the DC-3, the C-46 was used as our primary passenger carrier.
The passenger airplanes were converted to transport category requirements, which included better engine cooling, a better firewall, and an engine fire warning and suppressant system. We even had smoke detectors for the belly compartments. In place of an auto-feathering system, power loss lights were installed to provide warning of engine power loss. A crude anti-skid system was installed but on gravel runways and snow and ice it was better to turn it off because the release time was too long, using up too much runway. It worked better on paved runways.
I never really appreciated what the airplane was capable of until after retirement when I did some flying for Everts Air Fuel in Alaska and operated into fields we used to go into with the smaller bush aircraft. Putting 14,000 lb loads onto 2,500 ft runways (sometimes shorter!) was common. It was physically demanding work. You had to load/unload your own cargo … manhandle a whole bunch of 55 gal barrels up the incline, chain them down, then unchain them and roll them out when you got to your destination.
The airplane handles better in three points with a load than empty . A light airplane becomes very unresponsive due to the low airspeed in the three point attitude. The first time I retracted the flaps I almost ran off the end of the runway. Leaving the flaps down on the landing rollout on short runways is essential to stopping since the flaps provide a good deal of aerodynamic braking. It's truly an STOL airplane. It will be a long time before there's a replacement for the C-46 in Alaska. However, spare parts are in short supply.
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