Helio Courier

Helio Courier
restored H-295 Courier with the markings of a U-10D of the 5th Special Operations Squadron
Type:	Light aircraft
Design country:	United States
Manufacturer:	Helio Aircraft Corp.
First flight:	April 8, 1949 (Helioplane)
Commissioning:	1954
Production time:	1954–1974, 1981? - 1984

Helio Courier refers to a family of STOL - light aircraft of the US manufacturer Helio Aircraft , developed since 1948, and except for private pilots, especially in Special Operations units were used for military purposes.

history

U-10B of the 5th Special Operations Squadron in Vietnam in 1969, s / n 63-13093

U-10D of the California Air National Guard

H-295

Helioplane as a prototype

The starting point for the Courier development was the Helioplane designed by Otto Koppen. With this, he pursued the goal of building a light aircraft in which all known aids for increasing lift are combined in order to achieve slow flight characteristics and high spin safety unmatched in this class. As the basis for building the prototype, Koppen used a two-seater Piper PA-17 Vagabond , which was heavily modified in the process. The wingspan was shortened by 23 cm and the hull was lengthened by 1.14 m. In addition, the machine received an additional door and a heavily revised tail unit. The landing gear was moved further forward and automatic slats were installed. In order to increase the effective area of ​​the landing flaps , the ailerons were set up in such a way that they could be lowered together with the flaps if necessary, which is now known as flaperon . Regardless of their position, however, the ailerons were always operated using the control stick. The rudder was split in two; the lower half was moved together with the ailerons, while the pilot controlled the upper half conventionally.

To compensate for the increased resistance caused by the large landing flaps during take-off, the Helioplane was fitted with a large Aeromatic propeller with a diameter of 2.75 m. Thanks to a belt drive with a reduction ratio of 2.3: 1, the propeller only turned between 1080 and 1200 min ⁻¹ . In addition, the aim was to increase the aerodynamic efficiency of the landing flaps due to the slower but greatly increased volume flow of the propeller. Koppen received a patent for a specially developed silencer that used the cooling air flowing out of the engine.

The prototype equipped with a Continental A65 ( aircraft registration N9390H) was built by EW Wiggins in Norwood (Massachusetts) and flew for the first time on April 8, 1949. The subsequent testing extended over 10 months and comprised 100 flight hours. Here, the expected very good short take-off properties could be achieved, which were far superior to any other contemporary fixed-wing aircraft. At the start, the Helioplane only needed 100 m to fly over a 5 m high obstacle.

Another prototype was built in 1950 for the subsequent four-seater version and named the Helioplane-4 . This was equipped with a 145 hp Continental engine and had the registration number N74151. The original Helioplane prototype was then named Helioplane-2 .

H-391B Courier and H-392 Strato Courier

The Helio plane 4 then sat Helio Aircraft under the designation H-390 Courier as a demonstrator for the marketing of the aircraft a. With the landing flap system and the automatic slats extending over the entire span, the Courier took over the high-lift aids of the helioplane. During the transfer to a planned demonstration in Canada, the machine crashed, the pilot William Dean was killed. The first series model of the four-seater version, built in 1952 and flown in 1953, was named H-391 Courier and was acquired by the US Army. However, it is doubtful whether two more H-391s were built, as a source claims.

The US Civil Aeronautics Authority (CAA) approved the model in September 1953. The series production was originally planned by Aeronca Aircraft Corp. in fact, the Courier was acquired by Helio in July 1956 and based in Pittsburg, Kansas, Mid-States Manufacturing Corp. manufactured. After the H-391, which was only built in one copy, the final series version followed with the H-391B Courier. The first H-391B made its maiden flight in 1954. A Lycoming GO-435-C2B2-6 with an output of 260 hp, together with a two-blade propeller, is used as the engine for the H-391B. The four-seater machine can be used as a five-seater thanks to an additional temporary seat instead of a luggage compartment. From 1956 a float version was also offered. By January 1959, Helio had built 110 Couriers, 94 of which were used as business aircraft and in industrial flight (today mostly seen by helicopters). Another source gives 102 copies as total production, so that probably no more H-391B were built after 1959.

The H-392 Strato Courier, presented in 1957, differs from the standard Courier mainly through the use of a charged 340 hp Lycoming GSO-480-A1A6 engine that drives a three-bladed Hartzell propeller. This version was intended primarily for aerial photography at great heights. But probably only one of the H-391B was converted.

H-395 Super Courier and H-295 Super Courier

The H-395 variant was introduced by Helio in 1958. It differs from the H-391B only in the use of a Lycoming GO-480-C1D6 with an output of 265 hp, which acts on a three-blade propeller with a diameter of 2.44 m. The improved six-seat H-295 Super Courier had its maiden flight on February 24, 1964. The Super Courier was used almost exclusively for military purposes. All that is known about civil use is that allegedly seven examples were produced with a reduced-power engine.

H-250 Courier Mk. II (ex Caballero)

In March 1964 Helio presented the H-250 Courier Mk. II, which was initially also offered with the additional name Caballero . This was a simplified, lighter six-seat version of the Courier. It was priced at $ 33,400, about $ 7,000 less than the Courier's price. The machine was redesigned in such a way that with a take-off weight increased by only 10 kg, a payload increased by 33% could be transported. The gearless 250 hp Lycoming O-540-A2B allowed a cruising speed of 254 km / h and a landing speed of 50 km / h and enabled a range of 1160 km. The take-off distance over a 15 m obstacle was 254 m. 41 of the H-250 had been made by the end of production in 1974.

H-700 and H-800

In 1967 a new company, the Helio Aircraft Company (HAC), acquired all rights to the Helio designs. The headquarters was set up at the previous location of the Helio production in Pittsburg (Kansas). The company began producing new versions of the Super Courier with the Model 600 (400 HP Lycoming IO-720) and Model 700 (350 HP TIO-540).

In 1969, Helio became a division of the General Aircraft Corporation (GAC) based in El Segundo, California . Lynn Bollinger acted as Chairman and Chief Executive Officer of GAC and initiated the planning of a STOL-capable 36-seat short- to medium-haul turboprop airliner. Contracts were still awarded to build a full-scale mock-up of the project known as the GAC-100, but the program was not completed. At the beginning of the 1980s, HAC also produced another 18 copies of the Courier under the names H-700 and H-800.

Currently (2017) Helio Aircraft LLC in Prescott (Arizona ) owns the rights to build the Courier.

Military variants

The US Army acquired the first serial Courier, the only H-391, and put it into service for evaluation in 1953 as the YL-24 ( US Army serial number 52-2540). Due to a lack of budget funds, no further purchases were made at short notice. It was not until 1958 that the USAF showed renewed interest in the model and bought three H-395 Super Couriers, which they tested under the designation L-28A . Although the machines were able to meet the expectations of the military and in some cases even exceed them, there were no further orders.

When the US Army and USAF faced the demands of the war in Southeast Asia in 1962, the L-28's STOL properties were once again seen as important to support operations in the jungle. Between 1962 and 1966 the American military procured a total of 195 H-395s with nine different orders. Of these, 29 were ordered as L-28A and put into service as U-10A in 1963, after the aircraft designation system was changed . 27 copies went to the USAF and two to the US Army. In 1963 and 1964, 78 more machines were delivered as U-10B, of which the USAF received 57 and the US Army received 21. From 1964 to 1965, 88 U-10Ds were purchased; the USAF received 36 and the US Army 52 machines.

The U-10B differ, apart from an increased fuel capacity, only in equipment details of the U-10A; the U-10D had six seats, further enlarged fuel tanks and a door that opened up to make it easier for paratroopers to drop off. Since the U-10 was able to operate from auxiliary areas the size of a football field, the Air Commando Squadrons , later renamed Special Operations Squadrons (SOS), received the USAF aircraft. Their areas of activity included visual reconnaissance, freight transport, dropping light goods from the air, missions in the context of psychological warfare , search and rescue missions and forward air controller tasks.

As part of Operation Farm Gate, the first U-10s moved to South Vietnam in 1963 to gain operational experience under combat conditions. For Psy-War operations (psychological warfare), the U-10 dropped propaganda material or wore loudspeakers on the sides of the fuselage to broadcast corresponding announcements. From 1964 the SOS U-10 flew hundreds of missions from bases in the highlands of Vietnam and from Laos and Thailand. The USAF withdrew the model from Vietnam in 1971 and in 1973 there were no more machines in their inventory.

In the service of the US Army, the U-10 were mainly used from 1965 to 1972 to support the Special Forces in Southeast Asia. A small number were stationed in Europe and the USA during this time. Although most of the U-10s in the active Army units were replaced by helicopters in the course of the 1970s, the reserve units of the Special Forces did not retire their last U-10s until 1985.

The mentioned production figures are based on ER Johnson (2013, pp. 419–421) and sometimes differ significantly from those in Andrade (1979, p. 172) and in an internet source.

Production figures given in the literature

source	U-10A (USAF / US Army)	U-10B	U-10D	Total
Johnson (2013)	29 (27/2)	78 (57/21)	88 (36/52)	192 (120 USAF, 72 US Army)
Andrade (1979)	29 (3 L-28A + 26 U-10A)	57	36	122
secretprojects.co.uk	25th	86	44	155

Technical specifications

Parameter	Helioplane-2	H-391B	H-395
crew	1
Passengers	1	3-4
length	6.80 m	9.15 m	9.37 m
span	8.70 m	11.89 m
height		2.69 m
Wing area		21.46 m²
Wing extension		6.6
Empty mass	385 kg	853 kg	924 kg
Max. Takeoff mass	611 kg	1362 kg	1778 kg
Top speed			283 km / h
Cruising speed		261 km / h at 2590 m	274 km / h in 2500 m (75% power)
Minimum speed		less than 50 km / h (30 mph)
Service ceiling		7040 m	7160 m
Range		1120 km, 1560 km with additional tanks	1355 km
Engines	1 x Continental C-85 ; 85 hp	1 x Lycoming GO-435-C2B2-6 ; 260 hp six-cylinder boxer engine with gearbox, constant-speed two-blade propeller	1 x Lycoming GO-480-C1D6 ; 295 hp six-cylinder boxer engine with gearbox, constant-speed three-blade propeller, 2.44 m diameter

Preserved copies

The Helioplane prototype, handed over to the National Air and Space Museum by Helio Aircraft in 1963 , is on display at the Paul Garber Facility in Suitland, Maryland.

See also

• List of aircraft types

literature

• ER Johnson: American Military Transport Aircraft , McFarland and Co., 2013, ISBN 978-0-7864-3974-4
• Howard Levy: Helio Aircraft - Database . In: Airplane Monthly February 2004, pp. 69–81
• John M. Andrade: US Military Aircraft Designations and Serials since 1909 , Midland Counties Publ., 1979, ISBN 0-904597-22-9
• Karlheinz Kens: Aircraft types - type book of international aviation , 4th edition Carl Lange Verlag, Duisburg 1963, p. 298
• Leonard Bridgman (Ed.): Jane's All The World's Aircraft 1950–1951. Samson Low, Marston & Company, Ltd., London 1950, p. 241c
• Devon Francis: Scoop-Wing Plane leaps off Lawn . In: Popular Science, October 1949, pp. 106-112

Web links

Commons : Helio Courier  - collection of images, videos and audio files

• Production list
• Designations and production list

Individual evidence

1. ↑ ^{a b} Brief historical outline of the development of the Courier
2. ^ ^{A b c} Leonard Bridgman (Ed.): Jane's All The World's Aircraft - 1959–60 , 1959, pp.
3. ↑ 's corporate website (English) ( Memento of 8 March 2019 Internet Archive ) (accessed on 11 January 2017) Courier at Helio Aircraft LLC
4. ↑ Photo of the YL-24
5. ↑ Helio model designations
6. ↑ ^{a b} Helioplane in the National Air and Space Museum