The Little World

As a kid interested in mechanical devices and particularly in aircraft and cars, there were a number of remarkably stupid ideas in my mind at the time. I would look at some fabulous machine and admire the external styling without the slightest notion of what might be going on inside. That’s pretty standard for a kid, but I managed to carry on the ignorance for a very long time afterwards.

For instance, the helicopter. The only one of these that ever explained itself to me by the external appearance was the Bell Model 47 – because I could see the aero engine set upright under the rotor shaft and did not have to imagine the transmission system. Even then I had no real understanding of the pitch control of the blades that let the thing actually move back and forth in the air.

My concept of what might be going on inside a Sikorski or Piasecki machine was just a blank. I knew the Sikorsky must have had something big under the domed nose in front but what it was ( it turned out to be a radial aero engine – surprise…) and how it made the blades on top turn was beyond me. So I was more than happy that Amodel decided to include a small representation of the insides of the Piasecki HUP Retriever – enough to finally educate me.

The engine is placed in the centre of the aircraft as it is the heaviest part of the thing. The bent housing is the main rotor drive shaft and the offshoot is the driveshaft for the front rotor – they have elected not to include the entire length of it.

But the real education comes when you consider that the aero engine is air-cooled and it is buried deep in the fuselage. That’s what the big opening in the front part of tail is for – to let the downblast from the main rotor flow in, over the fins of the motor, and out the round hole in the bottom of the fuselage. Logical. They interpose an oil cooler just under the engine as well.

Which means there is no firing this one up and idling it without the rotor turning – there needs to be air moving through the fuselage from the start. A dangerous machine to be around.