Hubbry Logo
Solar T62Solar T62Main
Open search
Solar T62
Community hub
Solar T62
logo
8 pages, 0 posts
0 subscribers
Be the first to start a discussion here.
Be the first to start a discussion here.
Solar T62
Solar T62
Solar T62
View on Wikipedia
from Wikipedia
T62
Solar T62T-27 engine used as auxiliary power unit (APU)
National originUnited States
First run1950s

The Solar T62 Titan is an American gas turbine engine used mainly as an aircraft auxiliary power unit (APU), conventional power generator, turboprop engine for fixed-wing aircraft or turboshaft engine for helicopters. A new turbine version was developed as the Solar T66.

Variants

[edit]
T62 Titan
The direct drive main production version.
T62T-2
80 hp (60 kW) at 56,700 turbine rpm for Boeing-Vertol CH-47A Chinook helicopters.[1]
T62T-2A
95 hp (71 kW) at 56,700 turbine rpm for Boeing-Vertol CH-47B / C Chinook helicopters.[1]
T62T-11
80 hp (60 kW) at 56,700 turbine rpm for Boeing-Vertol CH-46A Sea Knight helicopters.[1]
T62T-12
105 hp (78 kW) at 61,240 turbine rpm
T62T-16 / -16A1
95 hp (71 kW) for Sikorsky CH-3, Sikorsky SH-3 and Sikorsky CH-54A Skycrane helicopters at 56,700 turbine rpm, with 8,000 and 8,100 rpm outputs.[1]
T62T-25
Turboshaft - 80 hp (60 kW) at 56,700 turbine rpm
T62T-27
Turboshaft - 150 hp (110 kW) at 61,250 turbine rpm, with 1x 8,000 and 1x 8,216 rpm outputs.[1]
T62T-29
Turboshaft - 95 hp (71 kW) at 56,700 turbine rpm, for Lockheed Jetstar and Pan American Falcon business Jets at 56,700 turbine rpm, with 1x 8,000 and 1x 8,100 rpm outputs.[1]
T62T-32A
150 hp (110 kW) at 61,250 rpm. Military Ground Power Unit (GPU) often used by US Navy and Air Force.
T62T-39
T66
A free power turbine version for the US military.

Applications

[edit]
Auxiliary Power Unit
Turboshaft
Turboprop

Specifications

[edit]

Data from Bennett[2]

General characteristics

  • Type: Turboshaft
  • Length: 33.41 in (84.86 cm)
  • Diameter: 21.375 in (54.293 cm)
  • Dry weight: 142 lb (64 kg)

Components

  • Compressor: Centrifugal Impeller
  • Combustors: Annular reverse flow with six burners
  • Turbine: Radial inflow impeller
  • Fuel type: JP-4 / JP-5 / JP-8
  • Oil system: Wet sump

Performance

  • Maximum power output: 60 to 150 hp (45 to 112 kW)
  • Power-to-weight ratio: 0.42 to 1.06 hp/lb (0.69 to 1.74 kW/kg)

Notes

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Solar T62

View on Grokipedia
from Grokipedia
The Solar T62 Titan is a compact, single-shaft gas turbine engine developed by Solar Turbines (originally Solar Aircraft Company) in the early 1950s as a small auxiliary power unit (APU) for military aircraft. It features a centrifugal compressor and radial inflow turbine mounted back-to-back on a common shaft, supported by a forward ball bearing and an aft roller bearing, with power output ranging from approximately 70 to 150 shaft horsepower (shp) depending on the variant and configuration. Primarily fueled by JP-4 or similar aviation fuels, the engine employs an annular reverse-flow combustor with six vaporizing burners and a central atomizing igniter, delivering reliable starting power and electrical generation for aircraft systems. Over 10,000 units have been produced across more than 40 variants, with continued use in legacy military, experimental, and ground power applications as of 2023. Widely adopted in U.S. military aviation since the 1950s, the T62 serves as an APU in helicopters like the CH-47 Chinook and CH-54 Tarhe, replacing ground support equipment for engine starts and powering hydraulic and electrical auxiliaries. Variants such as the T62-T-2A (78 shp, higher input speed for CH-47 use) and T62-T-16A (adapted for lower temperature limits in CH-54) highlight its adaptability, while later models like the T62T-32 support 60 kVA 400 Hz generators for ground power units. Beyond military roles, it has been employed in experimental single- and two-seat helicopters, turboprop conversions, and marine applications, emphasizing its low-cost, reliable design over high efficiency.

History

Development

The Solar T62, also known as the Titan, was initially developed by the Solar Aircraft Company in the early for a one-man application, later adapted as a compact gas turbine for use as an (APU) in such as the C-130. The design emphasized simplicity and cost-effectiveness through a single-shaft configuration with a radial and , aiming to provide onboard self-sufficiency for functions like main starting and ground power checkout. Key design goals focused on delivering reliable, lightweight power to overcome the limitations of contemporary engines, which were heavier, less efficient, and more vibration-prone for auxiliary roles in . Engineers targeted a high in a small package, enabling installation in space-constrained aircraft environments while maintaining operational reliability across varying altitudes and temperatures. Development evolved from earlier Solar prototypes, including the 50-horsepower Mars gas turbine introduced in 1956, with the T62 representing a slightly larger iteration rated at approximately 80 shaft horsepower (60 kW) in its initial T62T-2 model. The engine achieved its first operational runs in the mid-1950s, entering service shortly thereafter as a U.S. Navy-designated T-62T series unit for auxiliary applications. Significant engineering challenges included mitigating high- and in rotating components, ensuring starting reliability under extreme conditions, and optimizing , shaft dynamics, and airflow distribution to sustain performance. These were addressed through the adoption of technology, featuring a single-stage radial with blade tip sweepback angles of around 50 degrees. Subsequent production and refinements continued after Caterpillar acquired in 1981.

Production and service

The Solar Division of , which included the production facilities for the T62, was established following International Harvester's acquisition of Solar Aircraft Company in early 1960. In 1981, acquired International from International Harvester for $505 million, integrating it as a wholly owned focused on turbines. Production of the Solar T62 began in the late as an adaptation of earlier Solar gas turbine designs for auxiliary power applications. Manufacturing continued through various military contracts into the 1980s. The T62 entered widespread service in U.S. military fleets during the 1970s, powering auxiliary units in helicopters such as the CH-47 Chinook and CH-54 Tarhe, accumulating thousands of operational hours in ground support roles. Its use peaked through the 1980s and 1990s before a gradual phase-out in favor of more efficient successors, driven by demands for higher power output and improved reliability. Post-production support for the T62 extended into the 2000s, with third-party providers offering parts, overhauls, and time-between-overhaul (TBO) extensions up to 9,000 hours for variants. Surplus units have been repurposed in experimental projects, including homebuilt helicopters and ground test rigs, sustaining limited operational life beyond primary applications.

Design

Configuration

The Solar T62 gas turbine engine employs a single-shaft configuration, consisting of a single-stage and a single-stage radial inflow mounted back-to-back on a common rotor shaft, with power extracted from the shaft via a reduction gearbox to drive accessories or output shaft power. This architecture operates on the , involving the continuous processes of , compression, , and expansion, with fuel burned steadily in the to sustain high-temperature gas flow without intermittent ignition events typical of reciprocating engines. Air enters through the inlet screen and is accelerated radially outward by the , achieving compression before flowing into the reverse-flow annular where approximately 25% of the air supports and the remaining 75% provides cooling; the hot gases then reverse direction to pass through the radial turbine nozzles and blades, driving the rotor and providing power to the output shaft. Engine startup is accomplished using a hydraulic, electric, or air impingement starter to rotate the to sufficient speed (typically 20-30% of rated), at which point starting fuel is introduced via dedicated nozzles and ignited by spark or glow plugs, transitioning to main fuel flow as the lights off and self-sustains the cycle. Fuel delivery and engine operation are governed by a hydro-mechanical , which meters flow based on compressor discharge pressure, ambient conditions, and speed signals to maintain governed speeds, prevent conditions via a dedicated switch (typically at 110% rpm), and ensure stable acceleration without electronic control modules in the base configuration.

Components

The of the Solar T62 is a single-stage centrifugal constructed from an , supported by a forward and an aft roller bearing, and capable of handling rates of approximately 1.6 lb/s. The features an annular reverse-flow design, consisting of a , liner, and shield secured by a V-clamp, with six equally spaced vaporizers connected to a circular manifold for distribution, and incorporates a drain . The is a single-stage radial inflow bolted directly to the rotor shaft. Both turbine rotors utilize high-temperature alloys such as nickel-based materials for the blades to withstand operational , while the shafting and supporting bearings are made from high-strength . Key accessories encompass a gear-type positive-displacement driven by the accessory gearbox to deliver at around 300 psi, a dry-sump lubrication oil system with a pressure pump, filter, scavenge pumps, and jets maintaining 15-25 psi using , and a single-stage planetary reduction gearbox that steps down the high-speed output to the power shaft. Overall, the Solar T62 employs lightweight alloys extensively, including aluminum for the and magnesium for certain housings like the gearbox, contributing to its compact dry weight of 142 lb while ensuring durability in high-stress environments.

Variants

Turboshaft variants

The Solar T62 variants represent adaptations of the core gas turbine architecture for delivering mechanical shaft power, primarily in configurations where output shafts drive transmissions, hydraulic systems, or electrical generators at adapted speeds ranging from 6,000 to 15,000 rpm. These variants maintain the single-shaft design with a and but incorporate gearboxes for power extraction suited to rotor or accessory integration, enabling reliable operation in demanding environments. The T62T-2 provides 80 shp at a turbine speed of approximately 56,700 rpm, configured for integration into the CH-47A Chinook helicopter to support propulsion-related accessory drives. Its output is geared down for compatibility with the aircraft's , emphasizing durability for intermittent high-load duties. An upgraded iteration, the T62T-2A, provides 80 shp while retaining similar turbine rpm ratings, serving the CH-47B and CH-47C Chinook models with enhanced power for heavier operational profiles. Key adaptations include a higher input speed tolerance and refined accessory drive housing to optimize integration with upgraded helicopter , allowing for more efficient power transfer at shaft speeds around 8,000 rpm. The T62T-11 delivers 80 shp at 56,700 rpm, tailored for the CH-46A Sea Knight helicopter, where it interfaces with the aircraft's drive systems to provide consistent shaft power for support. Its configuration features a compact gearbox for output speeds compatible with the Sea Knight's rotor transmission, prioritizing corrosion resistance and ease in naval environments. For broader applications like the , the T62T-16 and T62T-16A1 variants offer 95 shp at comparable turbine speeds, with geared outputs adapted for transmissions in heavy-lift platforms. These models incorporate lower input speed requirements relative to the T62T-2A, facilitating smoother integration into diverse rotor systems while maintaining high reliability for sustained shaft power delivery. The T62T-25 serves as a general-purpose option rated at 80 shp, designed for flexible propulsion adaptations without model-specific tailoring, featuring standard shaft speed reductions for transmission compatibility. Higher-power needs are addressed by the T62T-27, which produces 150 shp at 61,250 rpm, suited for heavier applications such as the Sikorsky S-65 series. It includes dual output shafts—one at 8,000 rpm and another at 8,216 rpm—for to advanced transmissions, enabling greater handling and operational versatility compared to lower-rated siblings.

APU and other variants

The Solar T62 series encompasses several variants adapted for (APU) roles and other non-propulsion applications, such as electrical generation and ground support, distinguishing them from propulsion-oriented configurations through features like integrated generator drives, protective enclosures, and compatibility with military jet fuels including , JP-5, and JP-8. These variants prioritize reliability in intermittent duty cycles, with enhancements in electrical output for powering or ground equipment, and often include self-contained and control systems for standalone operation. The T62T-12 serves as a foundational APU variant rated at 105 shp, designed primarily for ground power generation to support starting and accessory operation without external equipment. It features a single-shaft with a radial and , delivering shaft power for hydraulic or pneumatic needs in maintenance scenarios. The T62T-29, rated at 95 shp, was developed for integration as an APU in business jets, providing onboard electrical and pneumatic power for , lighting, and start during ground operations or short flights. This variant emphasizes compact packaging and quick response times, with a hybrid fuel control system to ensure stable performance across varying altitudes. A higher-output military ground power unit (GPU), the T62T-32A delivers 150 shp and is equipped with a heavy-duty reduction gearbox to drive a 60 kVA, 400 Hz generator, often producing 28-115 V DC output for aircraft servicing by the US Navy and . Enclosed for rugged field use, it includes accessories like fuel pumps and ignition systems tailored for reliable emergency power in forward-deployed environments. The T62T-39 represents an enhanced APU variant with improvements in reliability and durability for , incorporating advanced materials in the turbine section and refined bearing systems to extend under repeated start cycles. It supports extraction alongside shaft power, enabling applications in environmental control and hydraulic actuation on business and . The T62T-40 series provides higher power outputs up to 250 shp in later models, used in advanced APU configurations for larger . Beyond core APU configurations, limited-production adaptations of the T62 were explored for small unmanned or experimental vehicles, though these saw minimal deployment due to competition from dedicated engines. Additionally, the series powered stationary generator sets for remote power needs, leveraging its modular design for easy integration with alternators. The T62 lineage evolved into the T66 as a successor, introducing a free power turbine for greater flexibility in power extraction while retaining the compact footprint.

Applications

Military applications

The Solar T62 gas turbine engine has served extensively as an (APU) in U.S. military helicopters, primarily to start main engines and supply hydraulic and electrical power while on the ground, thereby reducing reliance on external support equipment. In the U.S. Army, the T62T-2A variant powers the CH-47 Chinook, the T62T-16A equips the CH-54 Tarhe, and the T62T-40-1 is used in the UH-60 Black Hawk, delivering approximately 70 shaft horsepower in these roles. U.S. Navy applications include similar APU functions in helicopters such as the CH-46 Sea Knight and (military SH-3 variants), supporting operations in amphibious and anti-submarine roles. The engine's integration dates to the era, with widespread use continuing through the 1990s across and platforms. The T62T-32A variant powers mobile ground power units (GPUs) for U.S. Air Force and aircraft, generating 60 kW at 400 Hz to support pre-flight checks and systems activation without onboard . These units have been deployed in field operations for , enhancing logistical flexibility in austere environments. Key advantages of the T62 in military service include its compact design, ideal for shipboard storage and installation in space-constrained helicopters, and a simple, robust construction that ensures reliability under harsh conditions like dust, salt, and vibration. However, its relatively high fuel consumption—characteristic of early small gas turbines—contributed to operational limitations.

Civilian applications

In 2012, surplus T62T-32A units—originally from military generator sets—were retrofitted with (PLC) systems, including DirectLOGIC PLCs and HMIs, to automate startup, monitor parameters like exhaust gas temperature and oil pressure, and enable reliable operation in civilian power generation roles. In , the T62 series powered auxiliary power units (APUs) in commercial and business jets, as well as regional aircraft, supplying electrical power, for , and pneumatic starting for main engines to enhance self-sufficiency at remote airfields. Specific integrations included variants for wide-body airliners like the and Douglas DC-10, and the , with power ratings evolving from 62 kW in early models (T-62T-2, introduced in the ) to 280 kW in later ones (T-62T-45, produced in the 1980s). Limited conversions adapted shaft-output variants for propulsion, though these remained niche due to the engine's intermittent-duty origins. Experimental adaptations repurposed the T62 for homebuilt helicopters, such as integrations in (now Rotor X Aircraft) kits and the single-seat Mosquito Aviation design, where its 90-150 hp output drove rotor systems via reduction gearboxes. Plans for turbine-powered versions of the Revolution Mini-500 kit also centered on the T62-2A1 model, with at least one completed example featuring the engine for enhanced performance over piston alternatives. Military-derived variants were occasionally modified for these civilian projects, providing a cost-effective option despite requiring custom fuel controls and cooling. Today, with production ceased after the , surplus T62 engines support legacy systems and hobbyist endeavors, available used for approximately $15,000 and finding use in experimental modifications. While upgrades like electronic controls extend viability for off-grid generators, the engine's age poses challenges from evolving emissions regulations, limiting new deployments but preserving its role in low-cost, remote power solutions.

Specifications

General characteristics

The Solar T62 is a compact gas turbine engine developed by , a subsidiary of Caterpillar Inc., primarily configured for (APU) roles but adaptable as a or . Originally designed in the late for applications including one-man helicopters, it features a single-shaft layout with a and radial inflow , enabling ground-based or aircraft-integrated operation typically managed by a single crew member. Key physical parameters for the T62T-32 variant include a of 33.41 inches (84.9 cm) and a diameter of 21.375 inches (54.3 cm), contributing to its suitability for installation in confined spaces such as nacelles or . The dry weight is 142 pounds (64 kg) with gearbox, with variant-specific weights varying due to accessory integrations. The engine utilizes military-grade fuels such as , , or , drawn from the host vehicle's supply system, and incorporates a system with a usable oil capacity of 1.5 US gallons (5.7 L) to support reliable operation in demanding environments (for variants such as the T74-CP-702).

Performance

The Solar T62 gas turbine engine provides a power output ranging from 70 to 150 shaft horsepower (52 to 112 kW) across its variants, achieving a power-to-weight ratio of approximately 0.42 to 1.06 hp/lb (0.69 to 1.74 kW/kg). The single-stage centrifugal compressor delivers a pressure ratio of 3.5:1, with airflow rates of 1.5 to 2.5 lb/s (0.68 to 1.13 kg/s) under standard conditions. Turbine inlet temperatures reach 1,450°F (788°C), supporting efficient extraction in the single-stage radial inflow . Specific consumption is typically 1.0 to 1.3 lb/hp-hr (0.61 to 0.79 kg/kW-hr) when operating on approved fuels such as or . Operational limits include gas generator rotor speeds of 56,000 to 61,000 rpm and an output shaft speed of 6,000 rpm, with a of 1,000 to 2,000 hours before overhaul.

References

  1. https://apps.dtic.mil/sti/tr/pdf/ADA136220.pdf
  2. https://www.militarynewbie.com/wp-content/uploads/2013/11/US-Army-aviation-course-Gas-Turbine-Engines-AL0993.pdf
  3. https://planeandpilotmag.com/diesel-power-to-pistons/
  4. https://gasturbineworld.co.uk/solar-gas-turbine-apu/
  5. https://asmedigitalcollection.asme.org/GT/proceedings-pdf/GT1985/79382/V001T04A002/4456412/v001t04a002-85-gt-124.pdf
  6. https://www.solarturbines.com/en_US/about-us/history.html
  7. https://www.caterpillar.com/en/company/history/history-timeline/meet-the-family-of-brands.html
  8. https://www.nytimes.com/1981/05/15/business/caterpillar-to-acquire-harvester-s-solar-unit.html
  9. https://apps.dtic.mil/sti/tr/pdf/ADA158514.pdf
  10. https://www.wpsturbines.com/WPS-West_Performance_Systems/FAQs.html
  11. https://library.automationdirect.com/gas-turbine-repurposed-with-plcs-issue-24-2012/
  12. https://www.globalsecurity.org/military/library/policy/army/accp/al0993/le7.htm
  13. http://www.technologie-entwicklung.de/Gasturbines/Solar_T-62/Engine_Details/engine_details.html
  14. https://www.redbackaviation.com/the-cobra-predator-turbine-powered-homebuilt-helicopter-engine-history/
  15. https://apps.dtic.mil/sti/tr/pdf/ADA178084.pdf
  16. https://www.laehelicopterscyprus.com/ultrasport496/engine.html
  17. http://www.chinook-helicopter.com/Publications/Theory_Of_Operation/CH-47_Theory_of_Operations.pdf
  18. https://www.tinker.af.mil/Portals/106/Documents/Technical%20Orders/33-1-37-3.pdf?ver=pXaNBrFylqC-5aJpf8spzw%3D%3D
  19. https://sikorskyarchives.com/home/sikorsky-product-history/helicopter-innovation-era/sikorsky-s-65/
  20. https://www.airresearch.com/features/stcsearch.php/holders/65250
  21. http://www.users.zetnet.co.uk/gas/t62t32.htm
  22. https://www.turbineaero.com/about-turbineaero/
  23. https://www.aircraft.com/aircraft/21996485/n700kl-1980-hawker-700a
  24. https://www.researchgate.net/figure/T62-40-1-Gas-Turbine-Engine-APU-from-UH-60-Blackhawk-Helicopter_fig2_267499225
  25. https://www.airvectors.net/avs61_1.html
  26. https://aviationconsumer.com/aircraftreviews/engines/small-cheap-fast/
  27. https://www.researchgate.net/publication/236342053_Centrifugal_compressor_of_a_100_kW_microturbine_Part_2_-_Numerical_study_of_impeller-diffuser_interaction
Add your contribution
Related Hubs
User Avatar
No comments yet.