An advertisement for the Learstar from the 1955-56 edition of Jane's All the World's Aircraft.

 

Artwork from the Learstar Flight Manual. (Source: 3)

 

 

INDEX

The Sales Pitch

The Scope of Works

Lear Personnel

What Makes it a Learstar?

Lear Supplemental Type Certificates

Lear Approvals

Subcontractors

Photos

The Australian Connection

Learstar Production List

Sources

 

 

One might not expect to find the Learstar on a website devoted exclusively to Australian Lockheeds but there is a connection. The prototype Learstar was formerly Trans-Australia Airlines' VH-TAZ and in all, three Australian Lodestars were participants in William P. Lear's enterprise to convert an already fast aeroplane into a high speed executive transport.

William P. "Bill" Lear (1902-1978) was a prolific inventor with numerous patents to his name, principally in the fields of electronics, radio navigation and aviation. Many aircraft of various types were fitted with Lear autopilots. One of his less memorable inventions was the 8-track stereo cassette but he is best remembered for later giving his name to the Learjet business jet.

As the Lockheed Lodestar became readily and cheaply available in the immediate post-war years, Bill Lear saw its potential for development. While the Lodestar was less attractive to the airlines because of its limited capacity, Lear was quick to recognise its value as a high speed corporate aircraft. Although other operators also engaged in enhancing the Lodestar, it was Lear who did so on an industrial scale with as many as sixty (60) conversions completed. The Learstar modifications were so extensive that it was certificated in the same category as contemporary airliners. The aircraft was approved as an extension of the Approved Type Certificate (ATC-723) for the Lodestar. Accordingly, the Learstar was also the most expensive of the Lodestar conversions on offer. A Lear price schedule (Source: 8) states that; "a combination package can be made available for a total investment ranging from less than $250,000 to more than $300,000." Nevertheless, the Lear order book surpassed those of cheaper competitors.

A production line was established in a hangar at Santa Monica, California and the prototype Learstar, N4848V (MSN 18-2612) flew for the first time on 10 May 1954 (Source: 13). Jane's All the World's Aircraft (Source: 12) states 10 May 1954 in the 1955-56 edition but the 1957-58 and 1958-59 editions state 19 May 1954. Source: 1 (Marson) also states 19 May 1954. This aircraft was later completed to production standard and delivered to Chance Vought Aircraft as N14L on 28 April 1955.

In January 1955 the Learstar Mark I was certificated by the Civil Aeronautics Administration in the Airline Transport Category. (Source: 12)

The first delivery, CF-BAO (MSN 18-2318) was on 26 February 1955 to British American Oil Company Ltd of Canada. (Source: 12)

The Learstar Mark II (external mods only) was granted a Supplemental Type Certificate (SA4-69) in July 1956 and the first delivery was N10P (MSN 18-2546) to Plymouth Oil. (Source: 12)

Initial deliveries were planned at two aircraft per month. (Source: 12)

Lear assigned a serial number to each Learstar and while not all of these serial numbers have emerged, the highest known number is 60. For a listing of Learstar conversions please refer to the Learstar Production List.

As the aircraft entered production, many options and variations thereof were available and it is likely that no two Learstars were identical except perhaps where an individual customer purchased more than one conversion. Curiously, Jane's All the World's Aircraft states that the Learstar was available in tailwheel or nosewheel configurations and yet a nosewheel option is not mentioned in Lear's publicity material and it would seem that Lear never produced a tricycle version although this was subsequently available from Howard Aero.

The following introduction to the Learstar is extracted from a contemporary Lear publication. (Source: 8).

 

THE SALES PITCH

 

The new Learstar is the only production twin-engine, transport-category airplane that can cruise at over 300 mph TAS at 10,000 feet, the only one that can fly 3800 miles non-stop, the only one that can cruise at 270 mph TAS using only 100 gallons of fuel per hour, and continue at this rate for more than ten hours. In addition, the Learstar offers 2000 feet per minute rate of climb, exceptional single-engine performance, and the ability to operate with ease from pocket-size grass-runway airports. For the first time, there is available an executive airplane with abundant range for transcontinental - or for that matter, intercontinental flights, at speeds competitive with fastest airline schedules. Yet the Learstar, with its excellent small-field performance, offers vastly greater utility to the business user than any airliner with equal speed and range. Equally remarkable is the Learstar's payload. It is routine, for example, at a speed of 280 miles per hour, to travel 1600 miles non-stop with a crew of two, twelve passengers, and almost 700 pounds of luggage. In extreme long-range operation, the Learstar will fly non-stop for 3800 miles at a true air speed of 216 mph. In short range operation, the Learstar can hau! thousands of pounds of cargo - 4000 Ibs. for 1000 miles, for example. The Learstar's spectacular performance is matched by the scientifically planned Learstar interiors, researched and developed during many years of experimentation under actual conditions of executive travel. These luxurious interiors, accommodating up to twelve passengers, make for higher aircraft utilization, because Learstar passengers fly more hours without fatigue. Learstar executive airplanes are built to CAA-specified airline standards, and are designed for flight qualification under the identical CAA ''4b'' specifications required of such modern airliners as DC-7s and Super Constellations. Learstars are the only airplanes designed specifically for executive use that are built to qualify in this category. The Learstar incorporates substantial portions of the basic airframe of the Lockheed Model 18 Lodestar. A recent Civil Aeronautics Board report covering a five-year period indicates that the Lodestar led all other airline transport types in safety - from every aspect. Now, despite this enviable record, additional safety features have been designed into the Learstar. These include structural reinforcement of concentrated stress areas, simplified systems and controls, additional automatic operation features, improved aerodynamic characteristics, and modifications to provide ease of access for inspection and maintenance, The monetary savings resultant from designing and building the Learstar around basic Lodestar structures have allowed the cost of each Learstar to be kept to approximately half the cost of a comparable entirely new airplane and to an even smaller fraction of the cost of any existing airliner with equal performance. Thus, for a relatively modest initial investment, and at comparatively low operating costs, the Learstar offers speed, range, safety and comfort comparable to that which could be derived from private ownership of a DC-6 or Constellation - plus the ability to use hundreds of airports closed to such large airliners.

 

THE SCOPE OF WORKS

 

The Learstar was offered in Mark I and Mark II versions. The Mark I version encompassed a full airframe and interior conversion while the Mark II was intended for Lodestars with an existing “satisfactory interior” while not disturbing the existing radio and instrumentation.

The following extract from Source: 8 describes the extent of the modifications.

 

A. GENERAL 1. The aircraft is completely disassembled, thoroughly inspected, and overhauled to CAA Specifications governing an 8000 hour check. 2. All modifications from the standard Lockheed configuration to a Learstar configuration are performed in accordance with CAA approved engineering drawings. All work is performed by competent personnel, and all repairs and modifications are accomplished with the use of approved type parts and materials of best quality. 3. A complete weight, balance and loading schedule is furnished with the aircraft upon delivery. B. AIRCRAFT TEARDOWN 1. The following parts and equipment are removed from the aircraft as the initial step in the overhaul and conversion.   a. Wing outer panels   b. Control surfaces   c. Empennage assembly   d. Landing gear assemblies   e. Engines and nacelle assemblies   f. De-icer system and boots   g. Anti-icer system   h. Heating and ventilating system   i. All radio, instrument, and electrical components, wiring, panels, ''J'' boxes, antennas, etc.   j. All systems (hydraulic, fuel, oil, etc.) complete with components, wiring and plumbing.   k. All rigging and pulleys   l. Cabin entrance door   m. Escape hatches   n. Crew compartment door   o. Baggage doors and liners   p. Cabin and cockpit windows and frames   q. Complete cabin, cockpit and lavatory interior   r. Forward cabin bulkhead   s. Cabin, cockpit, galley, and lavatory flooring     2. The exterior of the fuselage, wings, empennage and control surfaces are completely stripped of paint. 3. A thorough interior and exterior inspection is made of the complete aircraft for corrosion, scratches, damages or wear and all discrepancies are corrected.   C. FUSELAGE MODIFICATIONS 1. Leading edge fuselage skin laps not parallel to the line of flight are faired with an aerodynamic seal to minimize skin turbulence and drag. 2. Baggage compartment doors are reworked for flush type handles. 3. Tumblers in main cabin door lock and #1 baggage compartment door lock are identical. 4. Two adjustable taxi lights of 250 watts each are installed in the nose cone. 5. A newly designed pilot's control pedestal is installed to allow additional foot room for easy entry into the cockpit and for accessibility to controls. The following controls are mounted on the pedestal: autopilot control head with approach coupler and altitude controller indicator lights; start, boost, and prime switches; visual autopilot trim indicator; carburetor air door control switches and position indicator; oil cooler door control switches and position indicator; cowl flap control switches; electric prop control switches and indicator; landing light switches; super-charger control switches and indicator lights; throttle controls; mixture controls; landing gear control; wing flap control; fuel boost pump switches and indicator lights; fuel selectors; ignition mag. switches; aileron elevator and rudder trim tab controls and indicators. 6. The front spar beam is lowered approximately 9 in. to the same level as the cockpit floor. The covered box that was originally installed just forward of the spar on the cockpit floor is no longer used, thus allowing easy access to the cockpit section. 7. New baggage liners in baggage compartments #2, #3, #4 are made of fiberglass ''V"' board approxi mately 1⁄16" in thickness. 8. The new flooring for the cockpit and cabin areas is of cellular aluminum construction offering superior strength with extreme lightness. 9. The original fuselage to stabilizer fairing saddle is removed and a new saddle of fiberglass construction is installed. This fairing extends approximately 7 ft. farther forward offering considerably less drag in this area, plus an excellent flush antenna location.   D. WINGS 1. The wings, ailerons, and flaps after being completely stripped of exterior paint, are thoroughly inspected, and all discrepancies are corrected. 2. The outer panels are completely rebuilt forward of the main spar in order to incorporate 240 gallon capacity integral tanks in each panel. In addition, the leading edge air foil from Station 228 to the tip is redesigned to a ''droop snoot'' configuration. 3. The wing tips are replaced by new reworked tips of Lear design. 4. All control cables and pulleys are inspected and serviced in accordance with standard 8000 hour overhaul practice. 5. The wing flap track extensions are cut off to limit wing flap travel to 55%, the Bat wings are removed, and the trailing edges of the wings and flaps are feathered and sealed.   E. EMPENNAGE 1. The stabilizers and control surfaces, after being completely stripped of exterior paint, are thoroughly inspected and all discrepancies are corrected. 2. All control cables and pulleys are inspected and serviced in accordance with standard 8000 hour overhaul practice. 3. The angle of incidence of the horizontal stabilizer is increased to eliminate the necessity for down elevator in high speed flight. 4. The hinged lid between the two elevators is fastened down permanently. 5. New horizontal stabilizer tips of fiberglass construction and Lear design are installed. 6. All leading edge skin laps not parallel to the line of flight are faired in with an aerodynamic sealer.   F. CONTROL SURFACES AND RIGGING 1. All contro! surface gaps are sealed with nylon brushes to prevent recirculation of air. 2. The flap operation is redesigned to incorporate a follow-up system which causes the flaps to stop at any preselected position. 3. An elevator spring tab system is installed, This modification allows the first movement of the control column to deflect the elevator tab before the elevator itself is moved, thereby reducing control forces. 4. A rudder spring tab system is installed. This modification allows the first movement of the rudder pedals to deflect the rudder tab before the rudder itself is moved, thereby reducing control forces.   G. CENTER SECTIONS A complete new nacelle assembly is installed, including new structure, new skin, mechanically actuated doors which completely enclose the main gear in the ''up'' position, and new stainless steel fire walls.   H. POWER PLANT SECTION The power package is completely redesigned (and as with all redesigned structure, manufactured from production tooling) to include: 1. New engine mounts which move the thrust line 3'' outboard. 2. New stainless steel diaphragms and dishpans. 3. NTSO 1425 h.p. Wright engines. 4. New Lord dynafocal mounts, Number RC-27A. 5. Aeroquip hose for all plumbing forward of the fire walls. 6. New AiResearch elliptical oil coolers and viscosity valves. 7. New elliptical oil cooler scoops, air exit flaps, and Lear electrical actuators. 8. Lear electrical actuators to operate the two speed engine superchargers. 9. Three zone fire detection systems of the thermal overheat type with 25 sensing units strategically located in each nacelle. 10. Carburetor alternate air doors with Lear actuators. 11. Augmentor type exhaust systems with three outlet troughs in each nacelle, exhausting one siamese and one single stack from each exit trough. 12. A new 4-section speed ring cowling mounted directly to the engine. 13. Carburetor air intake scoops which are removed from the upper side of the engine cowling and installed inside the upper speed cowl ring. 14. Cam-Loc fasteners for all accessory cowling. 15. Cowl flaps at two exhaust ports electrically operated by Lear actuators. 16. New Hamilton-Standard props type 33D50 with squared tip 6511A-12 blades. 17. Double capacity prop governors incorporating type 5U electrically operated control heads. 18. Individual starter and prop feathering pump units. 19. Engine accessories which will be either new, or overhauled and certified, at Lear's discretion.   I. INSTRUMENTS AND VACUUM SYSTEM The instrument system is redesigned and manufactured to include: 1. A new instrument panel manufactured to Lear design and laid out to customer specification. 2. Instruments which will be either new, or overhauled and certified, at Lear's discretion. 3. Panel lighting controlled by three rheostats. 4. Instrument dial lettering in accordance with Spec. AN-L-1A. 5. A vacuum warning system. 6. A cockpit fire warning system which will include both a warning bell and red indicator lights.   J. HYDRAULIC SYSTEM 1. The main hydraulic system is redesigned. All plumbing is new and fabricated on a production basis. 2. The main hydraulic system is supplemented by a complete emergency system with pressure supplied by an electric emergency pump. By means of a placarded cockpit selector valve, it is possible to divert emergency pressure as desired to the flaps, landing gear or brakes. 3. The brake hydraulic system is modified to incorporate an additional power brake valve with emergency plumbing to a shuttle valve located directly adjacent to each brake. 4. Electrically actuated fire wall shut-off valves are installed. 5. Pump failure warning lights are located on the instrument panel.   K. ENGINE OIL SYSTEM 1. The engine oil system is redesigned. All plumbing is new and fabricated on a production basis. 2. Overhauled and certified oil tanks are installed and incorporate liquidometers, hoppers for cold weather dilution, and a standpipe to insure a sufficient quantity of oil for prop feathering operations. 3. Electrically operated fire wall shut-off valves are installed.   L. FUEL SYSTEM 1. All fuel tanks are completely desealed and resealed with EC601 or EC801. 2. The outboard auxiliary fuel cells are complete with liquidometers and fuel dumping provisions. 3. Fuel capacity now consists of the original 644 gallon inboard tanks, plus an additional 240 gallons in each outboard tank, making a total of approximately 1124 gallons. 4. A dual fuel system is installed to make all tanks except the two inboard forward tanks selective to either engine. 5. Constant reading fuel quantity gauges are installed for all six tanks. 6. Flush type fuel sumps are installed in all tanks.   M. LANDING GEAR, WHEEL, AND BRAKES The Aircraft's landing gear system is redesigned to include: 1. Specially modified new Goodyear 12.5 x 16 wheels. 2. New Goodyear single disc, three spot brakes. 3. New tires and tubes. 4. A new hydraulically actuated mechanical landing gear uplock and downlock system incorporating sequence valves to eliminate the possibility of applying either ''up'' or ''down'' hydraulic pressure to the retract struts until the gear is unlocked. 5. New mechanically actuated main landing gear doors which are closed when the gear is either up or down. a. A fully retractable tail gear fitted with doors which are closed when the gear is either up or down, b. A new fuselage tail section to house the retracted tail gear. c. A streamlined fiberglass closing tail cone with provisions for identifications lights and T.V. antennas. d. A tail wheel swivel lock which is automatically released when the control column is pushed fully forward and is spring loaded to lock upon pulling the yoke back approximately 1⁄4''. e. An emergency tail gear mechanical hand crank located in the lavatory section for use in case of electrical failure.   N. ANTI-ICER SYSTEMS The system is redesigned to include: 1. All new plumbing throughout, fabricated on a production basis. 2. A modified windshield anti-icer system. 3. A new 15 gallon capacity carburetor anti-icer tank installed in the right hand engine nacelle. Alcohol is supplied to both carburetors from an electric pump adjacent to the tank. 4. A new 15 gallon capacity propeller and windshield anti-icer tank installed in the left hand engine nacelle. Alcohol is supplied to both propellers and the windshield from two electric pumps located adjacent to the tank. These pumps are rheostat controlled from the cockpit to deliver the desired amount of alcohol. 5. Electric shut-off solenoids mounted at the fire wall for the carburetor alcohol system.   O. CO2, SYSTEMS 1. A completely new engine CO2, system is installed consisting of two 11.66 lb. capacity CO2, bottles located in #2 baggage compartment. It will be the Walter Kidde electrically operated two-shot type with selector switches allowing for one bottle to either engine or both bottles to either engine as selected. 2. Nacelles and power plants are plumbed for protection to zones #1, #2 and #3. 3. A heater CO2, system of the Walter Kidde one-shot electrically controlled type is installed in the nose baggage compartment.   P. HEAT AND VENT SYSTEM A janitrol 100,000 B.T.U. heater system is installed and includes: 1. Hot or cold air which may be controlled from a panel in the cockpit as required for windshield defrosting or cockpit heat. 2. Cabin temperature controlled by a Barber-Coleman automatic system. 3. A ground blower for ground operation of the heater or for circulation of ambient air while on the ground. 4. A heater ram air inlet located in the center of the nose cone for minimum drag. 5. Individually controlled cold air outlets at each crew and passenger station. 6. Special lining in the heat ducts under the floor so as to prevent radiation heat loss. 7. Individual hot air outlets adjacent to the passenger chairs and divans.   Q. OXYGEN SYSTEM 1. The oxygen system is of completely new design using all new components and new plumbing fabricated on a production basis. 2. This system is the constant flow type automatically regulated and requires no adjustment when altitude changes are made. 3. Oxygen outlets are provided at each passenger and crew station.   R. ELECTRICAL The electrical system is completely redesigned to include: 1. All new wiring conforming to MIL-S-5086 and MIL-S-7078. 2. New batteries of an 88 amp. hour capacity. 3. A special Learstar raceway and conduit system. 4. A master electrical junction pane! mounted in the nose compartment of the aircraft. 5. New firewall junction boxes. 6. AN3161P circuit breakers. 7. Console switch and circuit breaker panels mounted below the instrument panel on both the Pilot and Co-Pilot sides of the aircraft. 8. A circuit breaker panel aft of the Co-Pilot's seat which will have all radio and autopilot fuses and circuit breakers, plus electrical circuit breakers not having to do with necessary in-flight systems. An AC frequency meter and an AC voltmeter with phase selector switch is also located on this panel. 9. All cockpit lighting controls mounted in the instrument panel. 10. High speed electric trim servos for manual use when the autopilot is shut-off. 11. Instrument panel lighting which will employ the Grimes eyebrow type fixtures. 12. Landing lights controlled by a three-way switch.   TYPICAL INTERIOR SPECIFICATION   A. COCKPIT-GALLEY AREA In order to offer the maximum features of safety and comfort in the ''front office,'' the new Lear design includes: 1. A wrap-around, panoramic windshield. 2. Special sliding cockpit windows. 3. Special cockpit chairs to allow maximum fore and aft, vertical, and reclining movement, upholstered in durable fabrics and leathers. Ash trays and cigarette lighters are included for pilot's and co-pilot's use. 4. Immediately aft of the co-pilot, a desk for pilot files, manuals, charts, and calculators. 5. Immediately aft of the pilot, a special stainless steel galley unit containing hot and cold running water, an ice chest for cold storage, a hot box for hot food storage, a hot cup and timer unit, and ample working space.   B. AIRCRAFT CABIN INTERIOR This is the ''living room" area, with the following features designed to insure maximum comfort during the long range flights possible in the Learstar: 1. At the main spar, Station 188, a bulkhead with special ''French doors"' to close off the cabin from the cockpit. 2. Immediately aft of this bulkhead, in the main cabin area, there are two lounges with removable cushions, safety belt attachments, and oxygen outlets for three or four passengers. These lounges are constructed of foam rubber, plus inner spring suspension for maximum comfort, the provisions underneath for a large amount of storage. 3. An alternate arrangement allows installation of a single 70° reclining seat with folding ottoman and and folding desk in place of either divan. 4. Immediately aft of each divan, there are two armchair-high storage cabinets. One cabinet houses provision for TV and FM-AM radio controls; the other serves as storage for blankets, pillows, etc. 5. Aft of the two storage cabinets is the club lounge area, featuring a large picture window on each side. Flanking these windows is a foursome grouping of the latest type Hardman fully reclining executive chairs. 6. Centrally located at each picture window is a Lear folding card table. The tops of these card tables enclose cigarette lighters, card storage, and a control panel for an intercommunications telephone. 7. Immediately aft, on the right side, is a cabinet containing complete bar facilities. 8. Opposite the bar cabinet is a matching storage cabinet to house blankets, pillows and miscellaneous articles. 9. These two cabinets back against the cabin-lavatory area bulkhead, which also features French doors. 10. Windows in the main cabin are of double thickness, with the inside pane of tinted glass. 11. The draperies when in closed position extend the full length of the cabin area on both sides. Above the drapes is a hand rail - air duct. This air duct is covered in durable plastic and houses reading lights and air vents for each passenger location. 12. Hidden from view in the upper portion of the air duct hand rail are indirect cabin lights. These lights extend the full length of the cabin on both sides. 13. A headliner is installed in continuous strips extending the full length of the cabin to give the appearance of greater length. Radio, TV, and intercommunication speakers are mounted under the headlining. 14. The wainscoting which extends the full length of the cabin on both sides is vertically pleated, padded with fiberglass insulation, and covered in a durable fabric. 15. The complete aircraft flooring is covered with a high quality carpet and a one-half inch layer of polyester foam under-rug designed for maximum soundproofing and resiliency. 16. Heat enters into the cabin area through small mushroom type units conveniently placed under the chairs and divans. 17. Miscellaneous items include rheostat controls for indirect lighting, ordinance lights, heater controls, and utility outlets.   C. LAVATORY AND VESTIBULE AREA This is the ''powder room'' area which contains: 1. A large wardrobe storage space, padded and covered in a durable fabric, with draw drape, and a shelf for hats, etc. A step light is also installed in this area. 2. A complete lavatory - upholstered and padded in durable materials for easy cleaning. The lavatory contains a wash basin, Kleenex dispenser, lighted mirror, magazine rack, paper toweling, an emergency call button, a 24V shaver outlet, and other necessary facilities.   TYPICAL RADIO SPECIFICATION   The following is an outline of a typical complement of radio equipment designed in accordance with current airline standards. A. NAVIGATION 1. Primary Navigation System, a) Omni Receiver b) Glide Slope Receiver c) MN97F Omni-Mag (combination cross-pointer and Omni bearing selector). Individual cross-pointer and Omni bearing selector may be used. d) Radio Magnetic Indicator 2. Secondary Navigation System. a) Omni Receiver (switch-over from Primary Communications Receiver) b) Omni-Mag or separate cross-pointer and Omni-bearing selector. 3. Low Freq. Navigation System. a) Dual ADF System (Lear ADF R-14) b) Dual ADF Indicator (ADF information may be supplied to RMI) 4. Marker Beacon System. Three-Lite Marker Beacon Receiver with HI/LO Sensitivity Audio Control (Lear 2200B Marker Beacon Receiver)   B. COMMUNICATIONS 1. Primary Communications System. a) VHF Receiver (installed with a switch-over system for use as a secondary navigation receiver) b) VHF Transmitter 2. Auxiliary Communications System. a) VHF Transceiver (Lear LVTR-36--36 channel VHF transceiver) 3. Audio System (Cockpit). a) Dual Channel Isolation Amplifier for both Pilot and Co-pilot Audio Selection

 

LEAR PERSONNEL

 

Driving the Learstar program was a veritable tour de force of engineering and management talent. A lavish Lear brochure, appropriately titled Capabilities and effectively a prospectus for the Learstar, lists them by name and qualifications (see below). Amongst them are people who had worked for (in no particular order) Lockheed, Boeing, Douglas, Chance Vought, Stinson, Bell, Howard, Vickers-Supermarine, Hawker, Goodyear, North American, General Motors, Raytheon, Consolidated Vultee, Ryan, Curtiss-Wright, Northrop, Hughes, Aero Commander and Martin. Some of the aircraft that these people had worked on included; C-74, C-124, DC-6, KB-29, F-86, C-123 and the boundary-pushing X-3. Is it any wonder that this team would later give us the Learjet?

 

 

Surprisingly, on 14 November 1956, Pacific Airmotive Corporation of Burbank, California announced the acquisition of one hundred percent of the shares in Learcraft Conversions Inc retroactive to 1 November 1956. The purchase price was not disclosed but the deal included 70,000 shares of Pacific Airmotive stock. The announcement also stated that; "Effective immediately, the former Lear subsidiary will be known as PacAero Engineering Corporation and will operate as a completely separate corporation. Vernon B. Benfer, former General Manager for the Lear Division, has been named President of PacAero Engineering. ... To date, 20 Learstars have been delivered and are in operation." (Source: 14)

From this point the aircraft was marketed as the PacAero Learstar. Seemingly, Lear had lost interest in the Learstar but no doubt they were clearing the decks as a protostar formed in the inventive mind of Bill Lear. This new star in the aviation firmament evolved as the little jet that was to bear the Lear name and enter the vernacular as a generic term for a business jet.

Other organisations persevered with executive conversions of the Lodestar and also the PV-1 Ventura. These conversions are mostly beyond the scope of this article but included the following providers, listed alphabetically:

 

The Other Players	Production
Aero Accessories	1
Dallas Aero Service Inc., Dallas, Texas	7
Executive Aircraft Services Inc., Dallas, Texas. (Gulfstar conversions for Gulf Oil Corp.)	5
Hamilton Aircraft Co., Tucson, Arizona	1
Howard Aero Inc., San Antonio, Texas	48
Oakland Airmotive, Oakland, California	3
Wiplinger Aircraft Service, Minneapolis, Minnesota	6

NOTE: The above figures should be regarded as approximate
as some Lodestars received modifications from more than one provider. (Source: 1)

To further cloud an already complicated picture, one conversion (MSN 18-2222) by PacAero was even further modified by Howard Aero, emerging as a Howard 250. The file for one Howard conversion (MSN 18-2140) confirms that the aircraft was fitted with a PacAero saddleback fairing. Many Lodestars have been photographed with extended noses and other Lear type airframe modifications but It is not clear if these components were supplied directly by Lear or other providers or if they were removed from retired or damaged aircraft that had been modified by the major operators.

 

THE NOSE

Seemingly, the most popular Lodestar enhancement was the lengthened nose which provided more space for baggage. Apparently, this was an option available from all providers of Lodestar enhancements. However, the first Learstar conversions retained the original Lodestar nose profile but with a transparent nose cone housing dual pitot heads and dual landing lights. The pitot heads were previously located on dual masts under the nose and would have been relocated for drag reduction. In the apparent absence of an STC for a lengthened nose, It would appear that this was approved as part of the original Learstar Mark I certification. The compiler can find only two Supplemental Type Certificates relevant to a lengthened nose, SA4-29 and SA4-72, both apparently held by Lear/PacAero and both for a "Radar nose Bendix C-Band or X-Band and RCA C-Band radar." Presumably there were subtle differences between the two. This STC probably represents the further extension of the Lear nose to incorporate a radome as illustrated below. The introduction of the lengthened nose with radar displaced the pitot heads and landing lights from the nose cone. The pitot heads were relocated to small streamlined mounts either side of the upper nose at approximately Station 54.5. The port location was just above the door to the nose compartment. The landing lights returned to their original location in flush retractable mounts under the outer wings.

Many Lodestars have been photographed with a lengthened nose that cannot be attributed to the known providers of Lodestar modifications so presumably Lear made parts available for fitment by the customer.

 

THE INTEGRAL WING TANKS

Another significant feature of the Learstar conversion was the installation of integral fuel tanks in the outer wing panels. These tanks each provided for an additional 348 gallons of fuel and hence an increase in the aircraft's range. Although performed under a Lear STC (SA4-57), the actual installation work was performed, seemingly exclusively, by Aircraft Tank Service Inc at Burbank. Evidently, this company had a small stock of converted Lodestar outer wings which were supplied to Lear at Santa Monica as required. Thus it would appear that most, if not all Learstars did not retain their original wings when they emerged from the Lear production line.

With the increase in range from the added fuel tanks, it became necessary to also increase the oil capacity. This was achieved under Lear STC SA4-58 which provided for larger oil tanks of 22.8 gallons each.

 

SPEAKING OF WINGS,
THE BAT WINGS - NOT A LEAR MOD

THE SADDLEBACK FAIRING

 

The original sheet metal "intersectional fairing" blended the fuselage into the leading edge of the raised tailplane as seen here on Lodestar VH-TAY (MSN 18-2613) at Brisbane, Eagle Farm in June 1952. This feature was more commonly referred to as the saddleback fairing. (Picture: Henry W. Pryor)

The outline of the Lear fibreglass saddle fairing is well defined in this photograph of a deteriorated Learstar C-FOZO in outdoor storage at Winnipeg on 11 June 2016. (Picture: George Trussell, Air-Britain Photographic Image Collection)

As discussed under Bat Wings above, early flight testing of the Lodestar resulted in a requirement to reposition the tailplane twelve inches higher on the fuselage. Raising the tailplane resulted in a noticeable step in the rear fuselage (as distinct from the Model 14 and Hudson) which featured a contoured sheet metal fairing which became known as the saddleback or saddle fairing. During the Learstar conversion this fairing was replaced with a longer fibreglass "horizontal stabilizer intersectional fairing" which removed the step and also became known as a saddle fairing. The new fairing extended approximately 7 feet farther forward than the standard Lockheed fairing and thus provided a flat level surface suitable for mounting an antenna or a rotating anti-collision beacon. Also during the Learstar conversion, the angle of incidence of the tailplane was increased by one degree to eliminate the necessity for down elevator at higher cruising speeds.

FAA files suggest that Howard Aero used the PacAero saddleback fairing STC on their conversions.

THE TAILCONE

Another distinctive feature of the Learstar is the extended tailcone. This began as a necessity to accommodate the retractable tailwheel but evolved, seemingly in three versions. Versions 1 and 3 are pictured below but Version 2 is more difficult to define. Indeed, its existence is only implied by the figures in the following table derived from the CAA airworthiness file for MSN 18-2613 N14WS pictured here.

 

LEAR TAILCONE INSTALLATIONS AND REMOVALS N14WS
VERSION	DRAWING #	WEIGHT lbs (rounded up)
Original	Lockheed	28
1	600371	10
2	6003113	28
3	6003147	51

 

Lear Inc at Santa Monica removed Version 1 from N14WS on 28 June 1956, just over one year after the aircraft was converted to a Learstar. This implies that the removed tailcone could not have been the original Lockheed Lodestar tailcone. An entry in the file for another aircraft (MSN 18-2182) records the removal of the "standard tailcone" weighing 27.5 lbs (presumably the Lockheed tailcone) and replacement with a Lear tailcone weighing 51 lbs. Also on 28 June 1956, Version 2 was installed on N14WS by Lear Inc. Several years later, in February 1968, Aerodyne Engineering Corp of Dallas removed Version 2 and replaced it with Version 3 in accordance with Lear Supplemental Type Certificate SA4-366. While dimensions are unknown, it will be noted that each version is progressively heavier

.

The original Lockheed tailcone on Lodestar VH-XUS at Wanaka, NZ (Picture: Ron Cuskelly)

Version 1 - The original Lear tailcone as fitted to N16L (MSN 18-2318).(Source: 7)

Version 3 - The ultimate Lear tailcone as fitted to N5056 (MSN 18-2500) photographed at Melbourne Tullamarine, probably on 4 April 1974. (Picture: John Hopton - The Collection p4600-0108k-790)

 

THE FLAPS & WING TO FUSELAGE FILLET

 

 

VARIATIONS ON THE THEME

While it is probably true that no two Learstars were identical, some of the aircraft received custom modifications that set them apart from the others.

 

APPROVALS REFERENCED IN SUBSEQUENT LEARSTAR CONVERSIONS

 

 

MSN	REGN	LEAR #	DATE	DETAILS OF MOD
2069	N44L (#2)	-	15NOV56	Elevator push pull rod.
2069	N44L (#2)	-	20JUN56	Extended tail cone.
2137	N80Q	-	26MAR57	Revised hydraulic system reservoir.
2147	N420L	-	03AUG56	Installed Aero Commander jump seat in galley aft of pilot per PacAero DWG 6003124.
2147	N420L	-	23MAR57	Electric carb heat actuators.
2199	N28L	-	11DEC56	Bendix dual ADF flush loops.
2234	N760AC	-	19SEP58	Grimes Rotating Anti-collision Light.
2238	N770AC	-	14SEP56	Revised aileron servo cable.
2238	N26L	-	24JAN56	Aft oxygen bottle 5 off.
2251	N37500	5	-	Stall warning system.
2311	N12L (#1)	-	01OCT54	Goodyear wheel and brake mod.
2311	N80A	-	21NOV55	Gross weight increased to 24,000 lbs. (See 2504)
2344	N80E	-	06DEC55	Revised pitot static system.
2421	N12L	8	29JUL55	Carb heat. Forward oxygen installation.
2467	N200L	-	25JAN57	Relocate prop feather throttle arming switch. Propeller vibration dampers. Electric engine blower actuators.
2478	N9980F	-	12JUL56	Bendix X Band per STC #SA4-72. Inverter system.
2504	N42LZ	-	10OCT55	Gross weight increase to 24000 lbs. (See 2311)
2504	N42LZ	-	10DEC55	Manual tailwheel lock.
2508	N16L (#2)	-	20JUN55	First PacAero conversion.
2508	N16L (#2)	-	04MAY55	Autopilot.
2508	N16L (#2)	-	01MAY56	Engine baffles.
2508	N16L (#2)	-	25JAN55	Electric propeller governors.
2573	N665	-	12NOV56	Rudder trim servo.
2573	N665	-	20NOV56	Electric elevator trim system.
2606	N44L (#1)	-	20JUN56	Extended fiberglass tail cone assembly Lear DWG 6003113.
2612	N14L	-	27APR55	Aft oxygen bottle 3 off.
2613	N24W	-	17APR55	Auto-feather and prop vibration dampener kit.
2613	N24W	-	05APR55	Rotating beacons bottom fuselage Station 286 and top fuselage Station 577.
2613	N24W	-	26APR55	Aft oxygen bottle (2 off?) see MSN 2612.
2613	N24W	-	27APR55	Bendix C-Band radar per STC #SA-11-29.

 

KNOWN LEAR/PACAERO SUBCONTRACTORS

 

The following table lists some of the subcontractors that appear in the CAA Form 337s. It is not necessarily complete.

 

COMPANY	SPECIALTY
Aerodex Inc, Miami FL	Engines.
Aircraft Propeller Service, Santa Monica CA	Propellers.
Aircraft Tank Service Inc, Burbank CA	Installation of outer wing integral fuel tanks, seemingly exclusively.
Curtiss Wright Corp, Caldwell NJ	Engines.
Durham Aircraft Service Inc, Minneola NY	Engines.
Grand Central Aircraft Co, Glendale CA	Engines and propellers.
Spartan Aircraft Co, Tulsa OK	Propellers.
Steward-Davis Inc, Gardena CA	Engines.
West Coast Propeller Co, Hollywood CA	Propellers
William R. Heydet, Yonkers NY	Engines and electrical.

 

 

LEARSTAR PHOTOS

 

The Learstar production line well underway at Santa Monica. (Source: 7)

The empennage of Learstar N16L (MSN 18-2318) showing the reprofiled tail cone which was to accommodate the retractable tailwheel. Later conversions had a further extension of the tail cone. Also shown is the reduced span of the tailplane tips outboard of the fin.(Source: 7)

The data plate from Learstar N5056 MSN 18-2500 pictured above. (Source: Peter Marson Collection)

Learstar N14WS (MSN 18-2613, formerly VH-TAY) was photographed at Fort Lauderdale on 4 October 1977. Note the further extension to the tail cone. The modified windshield and cockpit side windows were installed in November 1963 in accordance with Business AirCraft Corp STC SA2-766. (Picture: Geoff Goodall)

Learstar C-FOZO (MSN 18-2209) photographed just outside Winnipeg while under tow to the Royal Aviation Museum of Western Canada in Winnipeg. The damaged port propeller is a result of a partial undercarriage collapse at Naniaivik, NWT on 12 August 1984.(Picture: Robert W Arnold Collection)

Learstar C-FOZO (MSN 18-2209) photographed just outside Winnipeg while under tow to the Royal Aviation Museum of Western Canada in Winnipeg. Some of the recovery crew are pictured with the aircraft (L to R) Vic Poole, Robert Arnold and John Datzkew. This image provides a good view of the modified Learstar engine cowling. It is speculated that C-FOZO could be the last Learstar in existence.(Picture: Robert W Arnold Collection)