A couple or more more.

[Galvin]

Here is one I've had personal contact with.

1.) What is a C-112? What were all designations assigned to that particular design?

2.) What was it developed from and what were the major features that made it different from that predecessor?

3.) How many C-112s were built and who operated it/them?

4.) What happened to the prototype?

5.) What were the designations of all the production versions, both the predecessors and the developed versions, civilian and military?

6.) How many different types of engines were used on the basic design, including the airplane from which it was developed and its later derivatives? And, of course, list the various engines by name, type and designation.

[JimCasey]

C-112 Liftmaster Douglas 1946 prototype civilian DC-6/C-118 - modified C-54

[jetmex]

Jim got it started:

XC-112 was a modified DC-4/C-54, it was a larger aircraft powered by a pair of R-2800 engines. Service evaluation variant became the YC-112. Only one was built. It later became the prototype for the DC-6 series airliner and cargo aircraft.

C-112 -- military version of DC-6 with four 2100hp P&W R-2800-34. XC-112A, redesignated to YC-112A. After service trials, it was surplused onto commercial airline service.
The XC-112 designation was assigned to a projected development of the C-54B that was ordered in 1945 and was fitted with R-2800-22Ws and a pressurized cabin. The project was cancelled. XC-112A was originally ordered as a C-54 variant but became in essence the prototype for the DC-6. The single aircraft [45-873] flew for the first time on 2/15/46. YC-112A was a designation associated with either the pre-production aircraft which were not built or was XC-112 redesignated.

Service version was the E/M/VC-118 in USAF service, R6D in the Navy.

The DC-6 was basically a lengthened, pressurized DC-4. DC-6A was the cargo version with a strengthened floor and cargo door, DC-6B was the passenger version. The DC-6C was a one off Combi, and many of the passenger airplanes were later converted to cargo by various modifiers.

Here's a quick, dirty breakdown of the DC-4/6 variants:

www.uswarplanes.net/c54.htm

Engines, anyone?? ;D

[Galvin]

So far so good. The XC-112 was in fact a stretched and pressurized C-54 (DC-4) that started life as a C-54 and became the first article for a series of military transports that would later be called the C-116 and a civilian airliner called the DC-6 and designed to compete with the Model 49/749/C-69 Constellation. The design was later further modified to compete with the model 1049 Constellation by adding Wright R-3350s, becoming the DC-7 in the process. A bit of wing centersection was later added to make it the long-range DC-7C, counterpart to Lockheed's long-wing 1649 Connie, probably the most efficient piston engined airliner built.

Only one XC-112 was built, later becoming the YC-112 and even later becoming the prototype for the DC-6 series. It was later sold to Mercer Airlines of Burbank, CA and was used for years to carry passengers out to the desert and to other destinations under Mercer's Supplemental Certificate. I used to see it quite often and was friends with Jim Seacombe, the pilot who probably flew it the most. Mercer had some pretty weird airplanes back then (1960s and 70s), airplanes which included a mix of P&W and Wright powered DC-3s and one DC-2.

The C-112 had one feature which was never installed on any of the other aircraft in the DC4 or DC-6 series; Curtiss Electric props. This feature was its eventual undoing because on take off from Burbank one drizzly day it slung one of those Curtiss Electric blades from the No. 1 prop through the accessory section of No. 2 nacelle and the belly of the airplane, the resultant imbalance resulting in the No. 1 engine doing about three whatinhells followed by an OhmyGod and parting company with the airframe, ending up in the middle of the Burbank runway.

The wayward blade took out all the hydraulics which prevented the gear or flaps from being retracted and, as Jim found out to his horror after nursing the airplane back around to land on the runway and dodging the engine in the middle of it, taking out the brakes. He had no choice but to take back off on three engines and try for Van Nuys, a mere five miles or so to the Northwest.

The engines apparently begn to overheat from being kept at full power due to the drag of the inoperative gear and flaps and as the power began to fade away, Jim elected to put it on the golf course in the Sepulveda Flood Basin immediately south of the Van Nuys runway.

(This happens to also be the site of the local radio control field.)

He almost pulled it off but hit the cinder block starter's shack for the golf course, taking the nose gear off and shoving the crew up into the radio racks. The two fllight attendants and a kid that just happened to be along for the ride got out without a scratch but the three crew were immobilized and severely injured to the point that the airport fire department had to get a powered saw to cut them free of the smashed cockpit. They were not real familiar with its operation however and what transpired caused an awful lot of rethinking about its use and the precautions necessary.

I saw the video of what happened next. A fireman fired up the gasoline powered saw and began cutting, fuel vapor ignited almost immediately and said fireman was pulled free with severe burns. The fire department then got the fire out quickly but not before it had asphxyiated the three injured crew.

I had been working on my biplane in the San Val hangar up until midnight the previous evening and Jim, who had been teaching a ground school there, had come out after class and kept me company for several hours just BSing and handing me a tool now and then. You just never know.

Now, list ALL the engines and weird configurations of the four-engined Douglas series of DC-4, 6, and 7 airplanes.

[Britbrat]

The DC-4E, developed jointly by Douglas Aircraft Co. and several airlines, was the initial DC-4 varient. Powered by P&W twin Hornets, it turned out to be a too much airplane for its payload (52 seats) and what it was supposed to do -- it was sold to the Imperial Japanese Navy.

After extensive testing of the DC-4E, Douglas developed a smaller, faster, and considerably less complex model with a greater payload. In spite of being an entirely different airplane, it was still called the DC-4.
61 DC-4s were produced prior to Pearl Harbour & ~1200 of various varients were built for the wartime military. Post war another 71 DC-4 1009s were built for commercial use with a large number of surplus military units also serving as commercial carriers.

The U.S. Army requisitioned the entire DC-4 production. The first 24, which were in advanced stages of construction, were taken in their airline configuration and designated C-54 "Skymaster" in the Army's C-for- Cargo (and Transport) series. The C 54 was powered by the P&W R2000-SDGB Twin wasp.

The remaining civil DC-4s, plus others ordered by the Army, were reworked for military cargo missions as C-54A by reinforcing the cabin floor, adding a large double loading door, and putting extra fuel tanks in the cabin. Total C-54A production was 252, with 57 diverted to the Navy as R5D-1s.

The Army was so pleased with the militarized DC-4 that it placed big orders and had Douglas set up a second production line in Chicago, where 155 of the C-54As were built.

The C-54B was like the A except for additional fuel tanks in the wings; 100 were built in Santa Monica and 120 in Chicago. Thirty went to the Navy as R5D-2s.

The C-54C was a unique one-only - a C-54A modified as personal transport for President Roosevelt. The cargo door was deleted, a special VIP interior and extra radios were installed, and there was an elevator for FDR's wheelchair. Improved versions came through with relatively minor differences.

There were 380 Ds, all built in Chicago, with 95 transferred to the Navy as R5D-3.

The C-54E (125 built, all at Santa Monica with 20 as R5D-4 for the Navy) was a convertible model that could be a freighter, a trooper, or have airline-type seating for VIP or straight transport use.

The C-54G was configured as a paratrooper and was the last mass-produced model, with all 162 built in Santa Monica. There were no direct transfers to the Navy this time; all 83 R5D-5s were -2s and -3s re-engined and brought up to C-54G standards.

Higher designations to C-54M (38), a coal-carrying modification for the Berlin Airlift, were mostly single experimental variations. Designations from C-54N and up resulted from redesignation of Navy R5D-1s through -5s in the unified services designation system of 1962, plus subsequent modifications as high as C-54V.

Large Army orders were cancelled after V-J Day, so Douglas completed 79 partially-built C-54Gs as civil airliners under the factory designation of DC-4-1009. The C-54G & later C-54 models, plus the DC-4 1009, were powered by P&W R-2000-2SD13G Twin Wasps.

Three other significant DC-4 types were produced by Canadair. The Canadair C-4 was a cross-breed of DC-4 & DC-6, with the wings of the DC-4, a DC-6 Fuselage (or a DC-4 fuselage depending on the model) and was powered by Rolls Royce Merlin 266 engines. It was built in two varients-- both designated as C-4s. The commercial transport version was pressurized (DC-6 fuselage) & was built specifically for TCA (Trans Canada Airlines), but was also purchased in significant numbers as the Argonaut by BOAC in Britain. The inboard exhaust manifolds on the Merlins were routed back over to the outboard side to reduce cabin noise.

The RCAF military North Star was unpressurized (enlarged DC-4 type fuselage) & the Merlins' inboard exhaust stacks were left pointing at the cabin -- probably the noisiest transport aircraft ever.

The third Canadair varient was the C-5 -- again featuring DC-4 wings & a DC-6 fuselage, but was powered by P&W R-2800-CA15 radial engines. The C-5 was used as by the RCAF as a VIP transport & was appropriately fitted out in luxurious style.

[Galvin]

Excellent. Still looking for one more major mod and possibly one more (proposed?) engine type.

[jetmex]

I think you might be talking about the last Douglas piston transport, the DC-7, which was basically a stretched DC-6B (does anyone see a pattern here? ;D ). The stretch allowed the addition of another row or two of seats, and, to keep up with TWA and their Constellations, it was equipped with the Wright R-3350 engine in various configurations. Unfortunately, it neither outperformed, nor was it more reliable, than the DC-6, and had the poor luck to start service at about the same time jets were arriving.

Then again, I could be wrong. NAAAAAHHHHH!!! ;D

[Galvin]

Nope, we kind of covered the DC-7s. I'm thinking of a major conversion of the basic DC-4 design that saw much service in a niche market for years. (Hint: Not in the U.S.)

The other engine conversion I was thinking of was a turboprop version given a separate Douglas suffix letter but I am not sure if it was built.

[jetmex]

Ah, then you're probably talking about the ATL-98 Carvair, modified from a DC-4, which had a bulbous forward fuselage designed for ferrying cars across the English Channel. The vertical fin was lengthened for additional stability.

When you mentioned turboprop, the first airplane that came to mind was the Canadair CL-44, but I think that was basically a Bristol Britannia.

[Britbrat]

I completely forgot about the Carvair -- I bet you're right.

The CL-44 was indeed a re-engineered Britannia. Some had swing-away tails for loading large cargo pieces.

[Galvin]

And Jaime gets the (winner of the Ugly as a Mandrill's Ass award) Carvair, the car ferry conversion of the DC-4 that served with the Bristol Frieighters ferrying people and their cars across the channel for years. Now they have the "Chunnel" and a different way to risk their lives just for the priviledge of driving their own car on the wrong side of someone else's roads.

The CL-44 was used extensively by Flying Tigers as a freighter in the sixties. My friend Howie Harder was an engineer on one that cracked up in Alaska and I found out the details in a rather odd way. I was at the local Benihana restaurant in the San Fernando Valley with a date and we were watching the Japanese chef do the Benihana trademark show of rapidly cutting up the shrimp and steak (shrimp one way and fingers the other) when another couple was seated.

We struck up a conversation with them and when I found that the gentleman was a Tigers pilot, I asked if he knew my friends who were working there. It turned out that he knew all of them. When I mentioned Howie Harder he said yes, he sure did know him and that if it wasn't for Howie he wouldn't be sitting there.

He was the captain on the CL-44 that had crashed after control was lost on an icy runway and Howie had pulled him from the wreckage of the inverted cockpit after all the pieces had stopped bouncing. He said that when they touched down they immediately knew that they had a problem. The airplane began to skate to one side of the runway, a main gear went into the ditch, the airplane slewed around the stuck main til they were going the opposite way, breaking off a wing and the tail in the process. The forward end of the airplane came to rest inverted off the runway. I asked what happened then and he said "at that point I lost control of the airplane."

The CL-44 was unique in that it had no hard linkage between the control column and the respective aileron or elevator controls, their movement being accomplished by the use of control tabs. I remember seeing them taking off at Burbank, the ailerons and elevators drooping until the speed was high enough for aerodynamic forces to start streamlining the controls. I always had it in the back of my head that this type of control setup was a 'get hurt' arrangement if I ever saw one and is probably the root of my distrust of the newer, but just as isolated from human control or interference, 'fly by wire' systems of today.