The Trener is a modified version of the LIBIS-18 single-seater Standard Class sailplane which first flew on 20 October 1964 and was designed by the Letalski Institut Branko Ivanus, Slovenija – LIBIS. Of wooden construction with cantilever shoulder mounted wings with tapered outer panels, the LIBIS-18 did not go into production.
The VTC Trener differs from it chiefly in having the all-moving tailplane mounted slightly higher on the sweptback fin and rudder, and an improved cockpit layout, the pilot sitting under a flush-fitting one-piece cockpit canopy. The Trener is also of all-wood construction, using beech and Swedish plywood, and has Wortmann wing sections giving a thickness/chord ratio of 18% at the root. The fuselage is a wooden monocoque with a non-retractable monowheel with a brake, andatailskid. An initial batch of 50 Treners is believed to have been ordered by the Yugoslav Aero Club, these being built by VTC at Vrsac.
Span: 49 ft 2.5 in Length: 22 ft 7.75 in Wing area: 139.6 sqft Aspect ratio: 17.35 Max speed: 136.5 mph (in smooth air) Max aero-tow speed: 93 mph Min sinking speed: 2.36 ft/sec at 48.5 mph Best glide ratio: 31:1 at 53 mph
This Yugoslav single-seater high performance Standard Class sailplane was designed by T.Dragovic and Z. Gabrijel, two young engineers at the Faculte des Siences Mathematiques in Belgrade, and the prototype, known as the Delfin 1, made its first flight in December 1963. It made its public debut at the 1965 World Championships at South Cerney in Gloucestershire, and went into production as the Delfin 2 at the Vrsac works of VTC – Vazduhoplovno Tehnicki Centar (Aeronautical Technical Centre).
The Mk 2, which first flew on 26 April 1965, differed from the prototype in having the plywood fuselage covering extended to cover the nose, a smaller sideways opening canopy, a rubber-sprung nose skid added and wooden instead of metal ailerons, and 27 of this version were built, four of which were later converted to Delfin 3s. The Delfin 2 achieved its first real competition success when it came 1st and 2nd in the Polish National Championships of 1966, no mean feat in view of the strength of opposition from the indigenous SZD designs.
The Delfin 3 first flew on 29 July 1968 and has a conventional tailplane instead of an all moving one, reduced fin sweepback and increased rudder area. It is of plywood-covered wooden construction; the cantilever shoulder wings have plywood-covered leading edges and fabric-covered rear portions, and wing tip ‘salmon’ fairings are fitted. There are metal Schempp-Hirth air brakes above and below the wing surfaces at 60% of the chord. The fuselage is a monocoque structure with a small cross-section made possible by putting the pilot in a semi-reclining position under a one-piece curved flush fitting cockpit canopy that opens sideways to starboard for entry and exit. The swept back fin is integral with the fuselage, and the fixed tailplane has a trim tab in the starboard elevator. Landing gear consists of a non-retractable unsprung monowheel with a mechanical brake and a rubber-sprung nose skid, plus a tail bumper.
Delfin 3 Span: 49 ft 2.5 in / 15.0 m Length: 22 ft 5.5 in / 6.85 m Height: 5 ft 3 in Wing area: 138 sqft / 12.82 sq.m Aspect ratio: 17.55 Wing section: NACA 633 618 Empty weight: 492 lb / 223 kg Max weight: 717 lb / 325 kg Water ballast: None Max wing loading 25.3 kg/sq.m / 5.18 lb/sq ft Max speed: 155 mph / 135 kt / 250 km/h (in smooth air) Max rough air speed: 78 kt / 145 km/h Stalling speed: 32.5 kt / 60 km/h Min sinking speed: 2.13 ft/sec / 0.65 m/sec at 46.5 mph / 40.5 kt / 75 km/h Best glide ratio: 31:1 at 54 mph / 47 kt / 87 km/h
This two-seater powered sailplane was developed jointly by VTC of Yugoslavia and Sigmund Flugtechnik of West Germany, under the design leadership of Dipl-lng Alfred Vogt and Dipl-lng Ivan Sostaric. The prototype, registered YU-M6009, made its maiden flight on 24 June 1972 in the hands of VTC test pilot A.Stanojevic; it was certificated in May 1973 and an initial order for 10 was placed by the end of that year. The SSV-17 is a low-wing monoplane of glassfibre sandwich construction with a conventional retractable undercarriage, seating two side-by-side; it resembles the Rumanian IS-28M2, but has a swept-back fin and rudder and a low-set tailplane; the fin spar is of steel tube. The wing has a light alloy main spar and Schempp-Hirth air brakes above and below, but there are no flaps. The fuselage is a semi-monocoque structure and the fuselage/wing centre section, 6ft 6%in wide, forms the cabin floor and also serves as the wing spar carry-through structure. The main wheels have coil spring shock-absorption and retract upwards into ‘knuckle’ fairings, remaining semi-exposed when retracted to minimise damage in a wheels-up landing. The tailwheel is fixed and steerable. The powerplant is a Franklin 2A-120-A two-cylinder horizontally-opposed engine of 60hp driving a two blade Hoffman propeller; but following the Franklin Engine Co’s cessation of engine manufacture the rights to produce and market this company’s range of air-cooled piston engines was acquired by Pezetel of Poland in 1975, to power such types as the Polish built PZL-110 Rallye. It is believed that only the initial batch of 10 SSV-17s was built.
Span: 55 ft 9.25 in Length: 23 ft 11.5 in Height: 9 ft 3.75 in Wing area: 199.1 sqft Aspect ratio: 15.65 Empty weight: 943 lb Max weight: 1,472 lb Max level speed: 155 mph (power on) Cruising speed: 99.5 mph (power on) Best glide ratio: 29:1 (unpowered) Min sinking speed: 2.79 ft/sec (unpowered) Take-off run: 820 ft Range: 497 miles
A tandem two-seat kit-built monoplane developed in Venezuela. First flown in January 1997.
Overlapping pusher propellers are mounted close in to the fuselage and the wingspan can be extended for special applications. Can be flown with or without the cabin doors. An optional ag-spray kit was available. The kit did cost US$24,995.
Top speed: 100 mph Cruise: 60 mph Stall: 22 mph Range: 250 sm Rate of climb: 1200 fpm Takeoff dist: 100 ft Landing dist: 200 ft Service ceiling: 15,000 ft HP range: 52-100 Fuel capacity: 24 USG Empty weight: 700 lb Gross weight: 1400 lb Height: 7.5 ft Length: 22 ft Wing span: 32 ft Wing area: 160 sq.ft Seats: 2 Landing gear: tailwheel
Engine : Walter Minor 6-III, 116 hp Length : 21.982 ft / 6.7 m Wingspan : 25.098 ft / 7.65 m Wing area : 96.876 sq.ft. / 9.0 sq.m Max take off weight : 1455.3 lb / 660.0 kg Weight empty : 1124.6 lb / 510.0 kg Max. speed : 167 kt / 310 km/h Cruising speed : 140 kt / 260 km/h Initial climb rate : 2165.35 ft/min / 11.0 m/s Service ceiling : 26247 ft / 8000 m Wing load : 14.97 lb/sq.ft / 73.0 kg/sq.m Range : 189 nm / 350 km Crew : 1
After a two year construction period the XPBS-1 prototype first flew on 13 August 1937. Initial testing with 1050 hp engines revealed a top speed of 227 mph. Stability problems traced to turbulence generated by the wings resulted in the addition of dihedral to the horizontal stabilisers. After being delivered to the Navy in October 1937, the XPBS-1 began competitive trials with the Consolidated XPBY2-1 in mid-1938. Consolidated won a construction order and the XPBS-1 was assigned to Patrol Wing 5 at NAS Norfolk, Virginia, to evaluate long-range patrol-bomber operations until shortly after the US entered World War II. In the spring of 1942 the aircraft was reassigned to VR-2 out of California for transport duties between the West Coast and Hawaiian Islands. On 30 June 1942, while returning from Pearl Harbor, the XPBS-1 struck a log in San Francisco Bay and sank. All on board escaped safely, the passengers including Admiral Chester W. Nimitz, Commander of the Pacific Fleet.
In December 1939, American Export Airlines approached Sikorsky (then operating as Vought-Sikorsky Divistion) with the proposition of creating a commercial variant of the S-44, with the option of acquiring three aircraft as VS-44As.
The VS-44A was a commercial version of the experimental XPBS-1 patrol-bomber flying-boat, which had been built for the US Navy and flown in 1937. Accommodating 40 passengers over short ranges or 16 with sleeping bunks, it was developed by Michael Gluhareff for American Export Airlines. Power was provided by four 894kW Pratt & Whitney Twin Wasp engines.
With war clouds gathering, on July 15, 1940, the new Civil Aeronautics Board granted AEA a certificate to operate between New York and Lisbon, despite protest of Pan American. AEA promptly exercised its December 1939 option on three all metal VS 44A flying boats, powered by four 1,200hp (895kW) Pratt & Whitney Twin Wasp engines, at a total cost of US$2,100,000.
The aircraft were designed to carry 26 passengers on shorter trips, but only 16 over the North Atlantic in sleeper berths. Passengers would enjoy comfortable seats convertible for sleeping, modern lighting and heating systems, and even a galley where stewardesses could prepare freshly cooked meals. It possessed a 3100 mile range, fully loaded, that would allow it to fly the Atlantic non-stop.
The three VS-44 Excalibur passenger flying boats for American Export Airlines were completed as XJR2S-1 for the Navy, but flown by AEA under contract. Civil registrations NC41880-41882 (ATC 752) were allocated, as well as USN s/ns 12390-12392. 04396-04398 were cancelled and possibly refer to the same aircraft. The designation JR2S-2 was used as an alternative.
Vought-Sikorsky VS-44A NC41881
Vought Sikorsky completed the first of the ‘Flying Aces’, named Excalibur, in January 1942. A day later, AEAs chief pilot, Charles Blair, eased the flying boat down the ramp and into the icy Housatonic River. Only taxiing tests were planned but, Blair insisted later, the huge airplane “accelerated like a startled greyhound” and lifted off without his permission. Blair brought the willful ship back down, took off again and made a low pass over the Sikorsky plant.
The Excalibur was soon joined by the Excambian and the Exeter, all named for American Export Lines steamships. As the Naval Air Transport Service had taken over the order by then (and contracted with AEA to carry military and government personnel and equipment), the VS 44As were decked out in blue camouflage, with American flags emblazoned on the port and starboard bows to fend off aggressive Allied pilots and anti aircraft gunners. To maintain them, AEA hurriedly erected a tent city at Port Washington on Long Island to house a temporary base until a hangar could be completed at New York LaGuardia. Even that would prove inadequate as the Navy’s requirements necessitated a larger fleet one that would consist mostly of Consolidated P12Y 3R Coronado flying boats, which beat out Sikorsky for a Navy contract. Charlie Blair commanded the Excambian’s initial crossing of the Atlantic on May 27/28, 1942, on the first of two survey flights. Those flights were designed to assure safe operations between Port Washington and Foynes, a flying boat port on the River Shannon, with a fueling stop in Botwood, Newfoundland.
When the Excalibur inaugurated passenger service on June 20, 1942, with Blair again in command, the eastbound flight was uneventful. Travellers relaxed as purser Bill Scouler and Dorothy Bohanna, enjoying her role as the world’s first trans Atlantic stewardess, dished up drinks and hot entrees.
On the return flight to the new LaGuardia base two days later, the crew faced strong headwinds and fog that had socked in Newfoundland, the refueling point. Assessing their grim fuel outlook, co pilot Bob Hixson remarked at one point, “Glad this is a boat.” To stretch mileage, Blair brought the VS 44A down to skim just above the waves. When the flying boat touched down on Flushing Bay 25 hours and 40 minutes later, AEA publicists could claim the first Foynes New York nonstop flight. But only 45 minutes worth of fuel remained.
Eastbound flights were almost always easier, with nonstops of 3,000mls (4,800km) possible in 20 hours or less. On one flight, with the help of hurricane driven tailwinds, Blair crossed from New York to Foynes in a record 14hr 17min. To avoid winter headwinds on westbound crossings, crews had to detour far south of the favored Great Circle route. After mid October, the Sikorskys sometimes flew a circuitous South Atlantic track, via Bathurst, a West African port near the equator much farther from New York than Foynes, their departure point. When they crossed the Atlantic westbound, crews often flew as low as 500ft (150m) to avoid higher altitude headwinds. “There were times when we flew so low that the windshields were spattered with salt spray,” Blair recounted in his book, Red Ball in the Sky. While low flights made for slow trips, they sometimes afforded spectacular views. Pan American Captain Mike Craig, whose father Jim succeeded Blair as chief pilot of AEA, once noted that passengers and crew members “often had memorable flights viewing such sights as seals bathing in freshwater pools atop icebergs a scant few hundred feet beneath their windows.”
AEA’s flightdeck crewmembers, all Naval reservists, dressed in civilian uniforms to avoid problems in neutral countries. Like Blair, the other eight original captains had abandoned secure jobs with domestic carriers such as Eastern and United for the challenge of flying the Atlantic in some of the world’s most exciting aircraft. They were joined by a number of co pilots who had flown Curtiss P 40 fighters in China with the American Volunteer Group.
The second VS-44A, Excambian, was delivered in May 1942, and the third, Exeter, in June. Shortly after all three became operational, they were formally impressed into the Naval service designated JR2S-1.
Excalibur was lost soon after it entered service in a setback to the new airline. A relatively inexperienced pilot, trying to take off from Newfoundland’s Bay of Exploits, forced the reluctant flying machine into the air, causing it to stall and plunge back into the bay. Eleven of the 37 on board were lost, along with AEA’s beloved flagship.
AEA’s two surviving VS 44As would make more than 400 trans Atlantic crossings before the war ended. As early as 1942, when the first VS 44As were being delivered, the CAB had agreed with Pan Am that the Civil Aeronautics Act of 1938 prohibited shipping lines from starting or acquiring airlines. American Export’s airline division would have to be sold, although the ship line could retain a minority interest.
Determined not to let his airline be swallowed up by its arrogant competitor, John Slater, executive vice president, sounded out American Airlines executive Ralph Damon about acquiring AEA. Damon advanced the idea with AA’s wartime president, Alexander ‘Ned’ Kemp, who announced in March 1944 that AA had contracted to acquire control of AEA through a stock purchase. The deal was contingent on government approval, and would be argued along with a case to sort out which US airlines could fly trans Atlantic routes after peace was restored. In the debate that followed, both the Board and Congress rejected Juan Trippe’s efforts to establish Pan Am as the sole US flag carrier for all international service. On July 5, 1945, the CAB gave American permission to purchase 51.4% of AEA’s capital stock from the steamship line for $3 million. AEA’s last flying boat service departed from Foynes on October 22, 1945, with Blair again in command. Both flying boats were sold in 1946 and flown to South America. In mid-1947 Exeter was destroyed during a night landing on the Rio de la Plata River in Uraguay operated by Skyways International, loaded with guns and ammunition intended for Paraguayan rebels, leaving only Excambian.
Blair, still restless, leased that survivor for charter work with his Associated Air Transport, while he flew for American Overseas Airlines. AAT used the VS 44A in summer 1947 to support the construction of the US base at Keflavik, Iceland, flying on one occasion to Stockholm. After retiring from Pan Am, which ultimately acquired AOA from American in 1950, Blair created Antilles Air Boats, a Caribbean commuter service in the Virgin Islands. With business booming for his ‘Streetcar Line of the Virgin Islands’, Blair purchased Excambian in January 1968 from Catalina Air Lines (formerly Avalon Air Transport) of Long Beach, California, for $100,000 to handle the traffic between St Thomas and St Croix. The aircraft was so severely damaged in a landing just a year later that it could not be economically repaired. It remained beached for years at St Thomas until Blair reluctantly turned it over to the National Museum of Naval Aviation at Pensacola, Florida, in 1976. However, as the Excambian was never technically a Navy aircraft, officials waffled about restoring it. It was still vegetating outdoors at the base when Blair died in September 1978 in an aircraft accident. Maureen O’Hara, who stepped in to take command of Antilles Air Boats after Blair’s death, knew something had to be done to save the aircraft. She finally asked the Navy to turn Excambian over to the Bradley Air Museum (now the New England Air Museum) on a permanent loan basis. Sikorsky veteran Harry Hleva mobilized some 130 volunteers to restore the derelict to like new condition at the Stratford plant where it was born. With the restoration accomplished over an estimated 200,000 man hours, Sikorsky trucked the aircraft in parts to the museum’s civil aviation hangar. Even in that cavernous building, the giant nearly touches the ceiling.
Vought-Sikorsky VS-44A NC41881 Wartime paint
JR2S Wingspan: 124’0″ Length: 76’2″ Top speed: 227 mph
VS-44A Engines: four 1050hp R-1830 Twin Wasp Wingspan: 124’0″ Length: 79’3″ Useful load: 27,300 lb Max speed: 210 mph Cruise: 175 mph Stall: 67 mph Range: 4900 mi Ceiling: 16,600′ Passenger capacity: 35