About
the General Electric T58 (series) Turbine Engine
The
T58 (series) is a free-power, axial-flow turboshaft engine.
The compressor has 10 stages with variable inlet guide vanes
and variable stators on the first three rows. The compressor
has a compression ratio of 8.3:1 and flows approximately 13
lb. of air per second at 26,300 rpm (at the gas generator).
The combustion chamber is of the annular design. The compressor
rotor rear shaft is made from 17-4 Precipitation Hardening
Stainless Steel. Two turbines drive the compressor, and one
turbine drives the load through the rear output shaft at 19,500
rpm
This
high reliability turbo-shaft engine was designed specifically
for powering helicopters. Initial development began in 1953,
with the first T58 engine tested on a modified HSS-1 helicopter
in 1957. T-58 production ended in 1984 with over 6,300 engines
produced.
Designed
of the free turbine principle the Gas Generator and Power
Turbine sections are not coupled. The engine weighs approximately
350 lbs and produces between 1200 and 1400 shaft horsepower
(depending on the exact T58 model and what agency designated
the power rating). Specific fuel consumption is 0.64 lb/shp/hr.
This
high power-to-weight ratio, together with its compact size,
makes the T58 engine an ideal power plant for helicopters.
As a matter of fact, the first
U.S. Jet Helicopter was powered by the General Electric
T-58. Currently the U.S.Navy overhauls the T58 at NADEP
Cherry Point . The US Coast Guard flew the T58-GE-6 in the HH-52A Helicopter nicknamed the 'flying lifeboat'. The Sikorsky S-62 was T58 powered also.
The
T58 turbine engine features:
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Type;
Axial Shaft (turboshaft)
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Number
of compressor stage; 10
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Number
of turbine stages; 2 low pressure,1 high pressure
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Combustor
type; Annular
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Max
rated power output; 1350 shp (Sikorsky S-61A-1)
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Specific
fuel consumption at max power; 0.6 lbs per hour per
HP
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20.2"
diameter
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55"
Length
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305
lbs dry weight
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Overall
pressure ratio at max power; 8.2
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The
T58 gas generator produces approximately 4200 horsepower,
of which about 1200 to 1400 horsepower is available
at the power turbine. Nearly two-thirds of the total
gas generator output (approximately 2800 horsepower)
is required to sustain engine operation. Here's an excellent introduction
to turbine engines presented by General Electric.
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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.
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The
T-58 gas generator consists of a 10-stage compressor, annular
combustor and 2-stage turbine. Efficient and stall-free operation
is ensured by use of the variable stator principle in the
compressor. The inlet guide vanes and stator vanes in stages
1, 2, and 3 are variable. A hydro-mechanical and electrical
fuel metering unit provides maximum engine performance without
exceeding safe engine operating limits.
The
power turbine section consists of a single stage turbine and
exhaust section. A reduction gearbox can be mounted on the
power turbine section, if required by the installation.
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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.
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The
T58-GE-3 was installed in the UH-1F Huey helicopter
The
United States Air Force awarded four contracts to build a
total of 150 UH-1F aircraft (equipped with a single T58-GE-3
motor) from 1963 through 1966. This particular T58-GE-3 turboshaft
engine was assembled by General Electric and delivered to
the Military in aircraft 66-1222 in 1966. Incidentally, the
very last UH-1F to roll off the assembly line was two aircraft
later (aircraft number 66-1224) in November 1966. The next
generation Hueys were powered with T53 turbines.
Considered
to be the most widely used helicopter in the world, the Huey
is currently flown by more than 40 countries around the globe.
Still rolling off the assembly line today (at $4.7 million
per copy) more than 9,000 aircraft have been produced since
the 1950s.
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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.
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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.
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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.
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My
T58-GE-3 Turbine Engine
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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.
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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.
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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.
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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
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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-SealŪ 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.
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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.
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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!
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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.
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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.
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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.
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I
took a little 'time out' (while I was waiting for parts) to
fabricate a TIG
welder cabinet so I can weld my brackets.
While I was
at it I made a few improvements
to my shop.
Specific
details of the T58 engine
Many
of these T58 details were posted in response to specific questions
I received. Contact me if you have a T58 question and I'll try to locate the answer.
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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.
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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.
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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
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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.
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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).
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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.
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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.
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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.
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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).
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GE
T58 Turbine Engine
Fuel and Lube Oil Requirements
Since we're discussing big motors in small vehicles, be sure
and check out Rob's V-6
powered Fiat Spider.
And you'll want to take a look at Dino's T58
powered boat project.
Thanks to Skagit
Media for donating the site hosting.
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