Boeing B-54B, the Half-Way Bomber

[jcf]

I've never seen pylon mounted turbo-props on an aircraft before. Certainly stands out.

Very appropriate too, the B-54B uses the same XT-40 engine as the XF-84H. But FOUR of them.................

Was the XF-84H the aircraft that made people physically sick when the engine was running ? If so what will 4 do ? 

The XF-84H issue has been exaggerated over the years. The physical effect only occurred if you were in the
plane of the propeller, if you were forward or aft of the prop there wasn't a problem. It was the frequency of
the sound rather than the volume that caused the physical reactions. The noise level was only a problem on
the ground and claims that it made the pilots sick were long ago dismissed by one of the program pilots. 

[jcf]

@PR19_Kit there's probably a good reason why you don't see turboprops on pylons.  We are probably all familiar with how dangerous the Avia S.199s with the HE-111 engines were.  What made them so dangerous was the large, wide prop blades combined with a very bad gear ratio for a single engine aircraft - this created an enormous amount of torque and made the plane prone to flipping over on takeoff if the throttle was advanced too quickly.  I imagine that turboprops would impose a potentially dangerous amount of torque on the pylon if they were so mounted, though that would be negated by having stacked contra-rotating props like this build does.  Something about it just doesn't seem quite right though, but that may just be me.

The potential issues have nothing in common with the S.199's issues, it's an apples and oranges situation.
Contra-rotating propellers cancel any propeller torque issues, and even with single rotation propellers it
would be easy to have the propeller and the engine rotate in opposite directions to reduce the effects.
It's a simple matter of gearing.

[zenrat]

@PR19_Kit there's probably a good reason why you don't see turboprops on pylons.  We are probably all familiar with how dangerous the Avia S.199s with the HE-111 engines were.  What made them so dangerous was the large, wide prop blades combined with a very bad gear ratio for a single engine aircraft - this created an enormous amount of torque and made the plane prone to flipping over on takeoff if the throttle was advanced too quickly.  I imagine that turboprops would impose a potentially dangerous amount of torque on the pylon if they were so mounted, though that would be negated by having stacked contra-rotating props like this build does.  Something about it just doesn't seem quite right though, but that may just be me.

The potential issues have nothing in common with the S.199's issues, it's an apples and oranges situation.
Contra-rotating propellers cancel any propeller torque issues, and even with single rotation propellers it
would be easy to have the propeller and the engine rotate in opposite directions to reduce the effects.
It's a simple matter of gearing.

With a single prop rotating in the opposite direction to the engine the torque on the pylon would potentially be less than that from a turbojet.

[PR19_Kit]

Did anyone ever build that configuration, with the prop going the other way to the engine? I can't recall it being mentioned anywhere, but I can see the advantages.

[jcf]

Did anyone ever build that configuration, with the prop going the other way to the engine? I can't recall it being mentioned anywhere, but I can see the advantages.

The Allison T56 is one example, the compressor and turbine rotors rotate clockwise,
the propeller turns counter-clockwise. When seen from the rear.

The Honeywell-Garret TPE331(T76) is available with prop final drive in either direction.

In the Pratt & Whitney Canada PT-6 the compressor and power sections are on separate
shafts and rotate in opposite directions.