If you have ever climbed a high mountain or spent time above 10,000 ft above sea level, you'll notice that you will find it harder to "catch your breath; the same is true for any engine, in particular aircraft engines. Therefore, extra air has to be force-rammed into the carburetor from a turbo system. There are two turbo sources for each engine, an internal supercharger inside the engine casing, in which air is rammed in via an impeller, and the external exhaust/air-driven turbo. The second turbocharger is an external system, pretty much like one in most modern vehicles; all have the same purpose to "ram" air into the fuel system. This article will not be an engineering technical explanation, so I will stay on track with what was recovered, shown in highlighted green, and how and where it fits in the engine and turbo system with all accompanying accessories.
Starting with what was recovered concerning the turbo system:
Each engine has a turbocharger, all four were recovered. These were built by Allis - Chalmers Manufacturing Company
Type Designation B-22, Contract Drawing # WW-8456556. General Electric also made the turbo turbocharger.
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Turbocharger Intercooler, built by AiResearch Manufacturing Division
Outboard Intercooler
Contractor #15-7674. The outboard intercooler, sits tight vertically in the nacelle.
Turbocharger Intercooler
AiResearch Manufacturing Division
Inboard Intercooler
Contractor #15-7674.Inboard coolers have a slightly different design compared to outboard. They sit horizontally behind the wheel-well inside the nacelle since the landing gear takes up the majority of the room within the nacelle.
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Oil reserve for turbocharger
The turbo system provides the fuel system more air (into the carburetor) from air that enters through two avenues of air ducting from small openings in the leading edge of the wings, the air travels down through a filter that is open from take off till 8000 ft level, when they are then closed. The air enters the top of the turbocharger and gets compressed, and then, the rammed air begins its way to the carburetor first, flowing through the intercooler to bring down the temperature of the air. Fresh air also enters the intercooler directly from the leading wing air duct to mix with the air from the turbo. If the air is too hot for the carburetor, unwanted detonation will occur causing a variety of unwanted trouble. The pilot controls the waste gate from the cockpit, which when closed forces the exhaust to be routed through the turbine bucket, spinning up to 23,000 RPM, when less manifold pressure and compression are needed, the waist gates can be adjusted; of course, this is the simplified version. The accompanying components pressurtol, regulator amplifiers, junction box for interconnection, and wastegate motor were recovered.
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Amplifier, Turbocharger Waste Gate Motor
Made by Minneapolis – Honeywell Company
The amplifiers supplied power to operate the waste gate in response to signals received from the other system control units. There was one amplifier for each engine, plus a spare that could be rapidly replaced if one failed. The amplifier received electrical signals from the system control units and amplified these signals to operate the waste-gate motor by energizing one of the motor windings.
The amplifiers were located in the radio section and one in the forward cabin. Four amplifiers were recovered.
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Turbocharger Pressurtol
Part # G16A2CA1
Made by Minneapolis-Honeywell Company
Actuated by manifold pressure variations at the carburetor intake, the induction-system Pressurtol was the primary sensing device of the turbo supercharger control system.
Nacelle Junction Box
The nacelle junction box, located
within the engine nacelle, provided
interconnection for the Pressuretol,
governor, waste-gate-motor leads,
and the main junction box.
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Waste-Gate Motor
Made by Minneapolis - Honeywell Company
Part # G303A-Y2CA1
Its function was the operating unit that moved the turbocharger waste gate of the exhaust to the open or closed position, in response to signals from the control system. This forced exhaust back into the turbo system or by-pass the system and back out into the open air.
WRENCH, US, 3/8” – 7/16” INCH, MADE IN U. S .A
THIS WRENCH “KEY” WAS DISCOVERED INSIDE THE TOP OF THE TURBOCHARGER WHILE CLEANING IT. THERE WAS NO CLEAR DAMAGE TO THE TURBO FOUND. THIS COULD HAVE BEEN A FAILURE FOR THE TURBO. AT WORST, THE TURBO WOULD HAVE MALFUNCTIONED AND WOULD HAVE PUT THE ENGINE OFF-LINE, AND CAUSED POSSIBLE DAMAGE TO BOTH ENGINE AND TURBO. A POTENTIAL OF FIRE WAS ALSO PRESENT. OF WHICH THERE WAS NO EVIDENCE. IT IS WITH EXTREME LUCK THIS DID NOT GET MIXED WITH THE TURBO BUCKET WHICH SPINS AT 20,000 RPM.
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