The DC-3 turbo prop conversion begs to differ says my friends at Basler.

I can't see where the statement about the height of the props due to "Short" landing gear makes sense. The prop tips are neither too close to the ground or the fuselage. As far as I know, the landing gear was never changed to a longer length.

Too bad it didn't work. Those were beautiful planes.

The propellers used with the YT-34 engines were Hamilton Standard Super-Hydromatic Constant Speed Propellers.
Use of Constant Speed Propellers allows the Powerplants to operate at a Constant Speed while then propellers pitch is changed to increase or decrease thrust, Throttle Lage simply doesn’t exist for these engine/propeller systems.

I've always wondered why this wasn't done more in the early fifties. I was in the Air Force in '71. At tech school we trained on both turboprop and reciprocating engines, at that time there were still many older reciprocating engine cargo aircraft in service. I became a C-130 crew chief, It was great duty because we flew with aircraft. I didn't realize how loud the were until a couple years later.In the early 70's I was in a weather squadron flying out of Ramey AFB, PR. We had '58 B model C-130's. We flew 12 or more hour slogs up and down the East coast, very loud inside when flying. We didn't have external fuel tanks so I shared the cargo bay with a huge internal tank, Benson tank, I had a bunk. Later In Thailand I flew to a new assignment on a C-118 aircraft. It was a four reciprocating engine plane. That ride was so quiet and smooth, I'll never forget the comparison. When you see movies depicting troops talking inside a C-130, that's nonsense, we practically had to use sign language if you weren't on headset! Turbo props at the time were very noisy.

Constellation always had long landing gear.

Some of these photos appear to be the original L-749 short body with the T-34 Turboprops.  There is also a photo of the "Elation", an L-1049 body with Allison T-56 turboprops, the engines used on the L-188 Electra and L-382 Hercules

At the same time Lockheed had trouble with the gearboxes of this Constellation the Soviet Union build the Tu-95 with four new engines with about 12000 hp and counter-rotating propellers. These have been improved and are still in use nearly three quarters of a century later.

It worked converting piston Convair 340's to turbo prop 580's.

Not sure why these Hamilton Standard turboprop propellers had squared tips. The square tips create more drag and propeller noise.

Yep, the cures were decades away. Just think of the latest versions of U.S. C-130's with their curved blades (& many more blades). They are so quiet now compared to the 4 fat, square edged blades older versions run. I live under the flight path of a former military base that still uses 1 side for military aircraft & the sound reduction is significant! Paul, from S. Central Tx..

GREAT TECHNOCAL INFO. I AM GETTING INTO
ANTIGRAVITATIONAL PROPULSION SOURCE. PLUS DESIGN OF THE CRAFT

It worked with C-47 air frames. Apparently Connie's airframe was more stretched without right rigidity margin for the turbo-props

This begs the question, Why not reduce the Horsepower of the engine?

Lockheed later built the 4 engine turboprop L-1011 Electra. The problem could have been solved by keeping the propeller diameter the same and increasing the number of blades to 4 or 5.

We only have a few pictures, so we will show each one about 10 times..no one will notice......

Retroffitting Radial Engines can be done,   refering to the Convair 512 and the Basler.

Convair did it with the 240 series

What was the weird noise at 3:44?

I'm surprised that they didn't try the engines from the Lockheed Electra, which were 4000 hp Allison 501 gas turbines.  These went on to power the Lockheed C-130 as well, and neither airplane had issues with supersonic blade tips.  I see they had at least one airframe with these engines.  I guess they realized that turboprops weren't going to be the future.

Great video!

The propellers on the L-1249/R7V-2/YC-121F were unique:  https://youtu.be/Nja8D4QpsMs