XP-72 ideas

[scooter]

Some ideas for XP-72 I've had kicking around (and I've probably batted around when talking about Jugs in general)...

Yank the corncob, and replace it with T56.  The space for the turbosupercharger can be turned into fuel, armor, avionics bay, chaff and flare dispensers.
4x M10 37mm autocannons in the wings
3 A-10-style main wet hardpoints and maybe 3-4 smaller hardpoints per wing.

[kerick]

Sounds like the turbo Mustang idea. I say do it!
You know you want to.........

[jcf]

The XP-72 had a shaft-driven mechanical supercharger rather than a turbo-supercharger. The impeller
was around 3' in diameter.



https://oldmachinepress.com/2018/03/05/republic-xp-72super-thunderbolt-ultrabolt-fighter/

[perttime]

I detect potential balance issues.
Allison T56 is half the weight of an R-4360. It is also about a metre longer.

You might have to give it a very long nose, especially if you want to place something heavy in the tail.

[kitnut617]

The XP-72 had a shaft-driven mechanical supercharger rather than a turbo-supercharger. The impeller
was around 3' in diameter.



https://oldmachinepress.com/2018/03/05/republic-xp-72super-thunderbolt-ultrabolt-fighter/

Now that's an interesting photo Jon

[jcf]

I detect potential balance issues.
Allison T56 is half the weight of an R-4360. It is also about a metre longer.

You might have to give it a very long nose, especially if you want to place something heavy in the tail.

Shorten the drive shaft between the engine and propeller gearbox.

Of course you'll still have a lot of length to deal with as the R-4360-13 used on the XP-72 was
only 50" long.

[jcf]

Seeing as the T56 already uses a driveshaft from the engine to the gearbox, install
the engine behind the pilot and use a longer driveshaft to a nose mounted gearbox.
Single exhaust coming out the side of the aft fuselage, or maybe a bifurcated pipe
exiting on both sides.
 
Perhaps shift the cockpit forward for a more modern "jet fighter" look with contra-props.

Maybe a 30mm cannon firing through the hub of a five-bladed propeller, P-39 on steroids.
That way you can keep the long nose for the ammo cans. 

[kerick]

Many times I've looked at pics of that engine and thought "why"...........

[jcf]

Many times I've looked at pics of that engine and thought "why"...........

Mounting options, rotate the gearbox 180 and you have an installation for a low wing aircraft.
T56 from a P-3.

[kerick]

I always wondered if the whole engine assembly was flipped for that. The thing I wondered the most was why that driveshaft was so long. Logical engineering reasons I'm sure.

[Old Wombat]

I always wondered if the whole engine assembly was flipped for that. The thing I wondered the most was why that driveshaft was so long. Logical engineering reasons I'm sure.

Airflow into the engine; air comes in via a chin (or top) intake, then has to be made to flow up (or down) around the driveshaft so that the air enters the engine relatively evenly across the face of the inlet; otherwise you end up with significant stresses all through the engine, from the compressor blades, through the combustion chamber & on to the turbine blades; which would lead to extreme vibration & then bits of metal being ejected at considerable velocity out of the fuselage, or out of the nacelle into the fuselage.

[kerick]

I guess I didn't realize the intake face was in that position but where else would it be?

[kitnut617]

I guess I didn't realize the intake face was in that position but where else would it be?

Well the PT6 intake is at the back end of the engine, exhaust at the front.

[jcf]

Intake for the Bristol Proteus is also at the rear, unlike the PT-6, it is also a full reverse flow
engine which exhausts at the rear. The installation in the Bristol Brittania, for example, has
an annular intake at the front around the full circumference of the nacelle.
You cannot view this attachment.

You cannot view this attachment.

[kitnut617]

And the A.S. Python also had the intake at the rear, plus the reverse flow idea with exhaust at the very rear with a similar burner arrangement.