Output power is extracted by a free turbine, which is mechanically independent of the gas generator rotor system. The photo on the left shows the bottom of the T58-GE-3 (this example is shown as it is stored on its side, nozzle down in the cradle). The performance charts (on the right) show power output of the early T58 engines.

I selected the T58-GE-3 gas turbine engine for its superior power to weight ratio (1,290 HP in a 309 lb. package or 1,044 KW in a 136 KG package) and because they are readily available as military surplus. The view on the right shows the top of the T58-GE-3.

According to my research this General Electric T58-GE-3 turboshaft motor originally powered a Bell UH-1F Iroquois (unofficially called the Huey) back in 1977.

Known as aircraft 66-1222 this "Huey" saw plenty of action while assigned to Det 2, 37ARRS
(Aerospace Rescue and Recovery Service), Ellsworth Air Force Base, South Dakota.

Then in 1982 aircraft 66-1222 flew for the Los Angeles County Fire Department and no doubt was involved in many a rescue mission.

The Los Angeles County Fire Department has been serving the community by providing fire suppression and medevac emergency services with various aircraft since 1962.

My research shows that in 1987 this engine was pulled for maintenance, preserved, and later sold.

I've not been able to determine the current status of aircraft 66-1222.

This is the view of my T58-GE-3 'in the crate' as it arrived. It's been in preservation for a few years just waiting for some action.

Here is the fuel control, oil cooler, tachometer generator, braided lines, and other components as received. This particular motor was in running condition, but had some parts removed when it was pulled from the aircraft.

The first order of business is to make some handling fixtures. I've cut some 3" angle to fabricate a cart. Have you seen the price of steel lately? I thought I bought 'angle iron' but I think they charged me for 'gold'!

I had some nice locking, swivel castors on hand that I had purchased earlier from the kind folks at the local recycle center. I used some scrap channel from my 'junk pile' for the wheel mount pads.

Some aluminum diamond plate will provide a solid work surface and dress it up a little.

I fabricated a "saddle" to correctly support the motor and here I add brackets to attach it to the cart. The engine is held in the proper location by wood blocks during fabrication. I left enough room on the cart for a pair of batteries and a fuel tank.

This cart will provide a strong support platform so I can roll the entire unit outside to perform run-ups and testing. While my neighbors don't seem to mind the noise from my Garrett GTP30-67 turbine they may be in for a surprise when I light off this baby!

The swivel wheels have adjustable brakes to prevent the motor from 'flying down the street' during high power. With an output of 1,290 HP that would definitely be one wild ride! Next I'll hookup all the lines and verify the correct routing. I'll also need to wire the start and indication systems

Thanks to several folks on Rec.Aviation.Homebuilt News Group for helping to identify this fitting as a 'For-Seal Straight Thread Run Tee' by Weatherhead as described in Eaton's Product Library. It's listed on page 12 of "Steel For-Seal® Fittings" under "Fitting Related Products".

The start sequence requires 200 psi of fuel pressure during runup and lightoff so I need to monitor the pressure. Since the fitting I needed is not commercially available, I cut the ends off another fitting and TIG welded it together so I could plumb a fuel pressure gauge into the fuel control circuit. After a few low power turns I'll replace this direct reading gauge with a sender for an electric (remote) indicator.

The starter leads needed some attention. After verifying the polarity I heat shrunk the leads with the proper color code.

I designed a terminal board out of some insulative material I had. The bottom layer matches the hole pattern on the intake of the motor and the top layer will give me a little more room to keep the terminals properly separated.

Now I have a secure place to connect to the starter leads. I've verified the fuel, lube oil, and air lines are all hooked up correctly (more photos soon). I've still got some instruments on order.

I removed some corrosion on the igniter box with my glass-bead blasting cabinet, then primed and painted it. Both igniters fired good on a bench check. That's quite a spark!

The oil tank cleaned up pretty nice (inside and out). I'll use this to lube the motor while running on the test stand then I'll fabricate a new one later to fit the contours of the boat hull.

I need to fabricate an intake screen for the 'bellmouth' on the right. It's fiberglass but looks a little like copper with a Hammerite paint treatment. I also need to design the throttle linkage, and install the tachometer.

This view shows the lube oil pressure gauge pickoff port (arrow A) on the side of the intake. I have a direct-reading gauge hooked up for troubleshooting.

I installed a high-capacity diesel fuel filter (arrow B) rated at 120 GPH and a Holley Marine fuel pump (arrow C) to supply fuel while on the test stand.

The fuel drain (arrow E) is located on the underside of the 'hot section' just aft of the Gas Generator Tach. Generator (arrow D). On shutdown fuel pressure is bled off from the fuel control.

On the T58-GE-3, a 'Flexicable' ("A") is driven off the underside of the Power Turbine ("B") by the Bearing No. 5 Sump ("C"). There are three different styles of Flexicables (from different manufacturers) and the parts are not interchangeable.

Here you can see where the Flexicable ("D") provides an input to the Fuel Control ("E") and also drives the Power Turbine Tachometer Generator ("F"). With two Tachometer Generators, the T58 allows the operator to monitor the Gas Generator RPM (controlled by the power lever or throttle) and the Power Turbine RPM (which varies with the load). No, the safetywire on "D" is not backwards, it's actually left-hand thread on that end of the flexicable.

Here's what the Oil Pump looks like (with the seal installed on Tach. Gen. drive shaft).

And here's the Oil Pump properly installed.

Here's an overview of the Fuel System showing the Flow Divider (as shown in Maintenance Manual NAVWEPS 02B-105AHB-2/T.O. page 2-13).

Here's a closer view of the Flow Divider from the same diagram

Here's the Flow Divider ("F") as seen on the motor (under the exhaust looking forward toward the gearbox). ("G") is the Fuel Control, and ("H") is the Fuel Cooler.

A quick check to verify all the lines are hooked up correctly before I turn the motor. This is the side view of the front.

Here's a larger view on the same side. The line left 'hanging down' is for the Fuel Control Drain. On shutdown I'll get about a pint of fuel drained off (as pressure is released and drained off from inside the Fuel Control).

Here's a view of the underside looking forward. You can see the Fuel Control (on the left) and all the fuel and sensor lines.

Here's a larger view of the entire underside. You can see the Power Turbine Sump (top center) and all the way forward to the Accessory Drive Gearbox.

Now that we've verified all the lines are correctly hooked up, it's time to 'turn' the motor. Here's the Left Side view on the cart, ready to 'windmill' (to check our pressures) before we start. You can see the Control Panels I fabricated for monitoring/controlling the motor while running on the cart.

Here's the Right Side view showing the Fuel Pump and Fuel Filter. That Racor Fuel Filter is rated at over 120 GPH as we'll need up to 110 GPH when this monster is running under load (at 100%). Power is provided by a pair of RV Deep-Cycle batteries.

Following my Turn Checklist, I cranked for up to 30 seconds and melted the post on one of the RV batteries. I must be pulling close to 500 amps (or more) during the start cycle. After a quick trip to the local Les Schwab tire store for a pair of 8D truck batteries, I'm now ready to try it again.

These monsters are rated at 1500 cold cranking amps (CCA). The red hose is a drain line to keep residual fuel (from the tailpipe) from draining onto the battery. While Kerosene and Diesel are both much safer to work with than Gasoline, I still don't like fuel spills.

Here's a closer look at the internal workings on the T-58. This gas turbine was torn down so a new 'hot section' could be installed. All internal parts are inspected to ensure they are within tolerance (as prescribed by General Electric and the US Navy).