Robinson R22
| Robinson R22 | |
|---|---|
 Robinson R22, Robinson Helicopter Company |
|
| Type: | Micro helicopter |
| Design country: | |
| Manufacturer: | |
| First flight: |
1975 |
| Commissioning: |
1979 |
| Production time: |
In series production since 1973 |
| Number of pieces: |
Over 4,000 |
The Robinson R22 , built since 1973, is a helicopter from the US aircraft manufacturer Robinson Helicopter . The concept envisaged a simple, light and inexpensive helicopter for training and monitoring purposes as well as private use. It is produced (as of 2010) in version R22 Beta II . The Robinson R44 is the slightly larger but similarly constructed sister model of the R22. With the Robinson R66 , Robinson has also been offering a turbine- powered model since 2010 .
description
The R22 is not powered by shaft turbines , as is common in helicopter construction today , but by a conventional piston engine from Lycoming . However, since a piston engine, in contrast to a free-wheeling turbine, cannot be started with a frictional connection with the rotor system, the use of a detachable coupling was necessary in order to separate the drive and load for the starting process. With the R22, this is achieved by a “stretching” tensioning device of the multiple V-belt drive between the engine and the main gearbox.
In order to achieve an acceptable power- to- weight ratio despite the piston engine , which is heavier than a comparable shaft turbine , the R22 is made of absolute lightweight construction. Everything was avoided that is not primarily necessary for operation. The reasons for choosing a piston engine were the significantly lower price and lower spare parts and maintenance costs compared to a turbine engine. Another advantage that results from this is that the helicopter can thus also be serviced and operated at airports that are not designed for the maintenance and operation of turbine aircraft or where no kerosene is available.
The widespread Lycoming O-360 , an air-cooled four-cylinder boxer engine , is throttled in its output in order to achieve the required service life and reliability despite the high thermal loads occurring in helicopter use. The lack of air flow and propeller wind due to the installation behind the airframe make forced cooling by a fan necessary, which also uses part of the available engine power. The R22 is designed for two people with small hand luggage, but without any other payload , and the standard version has no instruments for instrument flight . The double control is not implemented via two separate control organs, but via a central control stick on which a kind of bracket is attached and thus enables control from both seat positions. Panels in the interior were also dispensed with, as was full paneling of the fuselage . Only in this way was it possible to keep the power-to-weight ratio not significantly above 4 kg / HP for the fully loaded helicopter.
With a base price of just over 240,000 US dollars, it is not only a cost-effective alternative to classic turbine helicopters for flight schools , but also affordable for sports and private aviation in terms of acquisition and maintenance ( maintenance / consumption). Most of the R22 are procured from flight schools and media companies. In Australia, many R22 are used in cattle patterning, the modern variant of cattle drive. It is especially in this usage aspect that the R22 can show its greatest advantage over its usually larger and heavier competitors: its almost unrivaled maneuverability. To do this, he uses an advantage of the piston engine, which reacts to power requirements considerably faster than a turbine. The R22 can change to slow or hovering flight at a very short distance from full speed .
However, accidents involving the R22 and the similarly constructed R44 from the same manufacturer increased up until the mid-1990s , which resulted in intensive observation by the aviation authorities. According to the investigations of the BFU , the poor ability of the helicopter system to absorb the effects of a failure or operating error was one of the causes of the crashes in many accidents. Flight conditions with low load factors (low gravity) and hectic control inputs in particular led to fatal crashes because the rotor blades hit the tail boom and the aircraft then disintegrated in the air. In response to this risk, the training guidelines and the establishment of the operating limits of the types R22 and R44 had to be modified.
Furthermore, the behavior of the uncharged piston engine , which changed in altitude, was fatal for some pilots. The power of such a motor decreases with increasing altitude much more than that of a wave turbine, since the latter can better compensate for the falling air pressure. In addition, there was the problem of carburetor icing , which is unknown to shaft turbines (and thus for pilots who were trained on turbine helicopters) and thus the sudden engine standstill.
Another disadvantage owing to the very simple design of the R22 is the low kinetic swing energy due to the weight-reduced rotor blades, which can be stored in the rotor during autorotation landings in non-powered descent. This residual energy in the rotor's flywheel mass must be sufficient for the pilot to place the helicopter safely and softly on the runners after landing (reduction of forward speed by lifting the aircraft nose). The decisive factor is the altitude at which the pilot performs the flare maneuver. Therefore, landings by autorotation until touchdown should only be carried out by experienced pilots. In school operations, autorotations are usually dispensed with until touchdown and the maneuver is ended a few meters above the ground immediately after leveling out by increasing the engine power, for which the engine must continue to idle during descent.
Fatal cattle drive accidents in Australia, in which the machines are flown without a safe altitude, safety speed and by inexperienced pilots with breakneck flight maneuvers, made a seriously negative contribution to the overall crash statistics of the R22.
A well-trained R22 pilot can feel very safe in his aircraft, especially since Germany, Austria and Switzerland have the fewest crashes per flight hour worldwide (source: Luftfahrt-Bundesamt 2007). This fact is not only attributable to the flight training regulations applicable there (a helicopter license for the R22 costs around 25,000 euros), but also to the fact that the prescribed maintenance plans are meticulously adhered to in the three countries mentioned.
Technical specifications
| Parameter | Data |
|---|---|
| length | 8.75 m (28.75 ft) hull length: 6.30 m |
| Rotor diameter | 7.67 m |
| Main rotor area | 46.21 m² |
| Tail rotor diameter | 1.07 m |
| height | 2.71 m (8 ft and 11 ″ ) |
| Top speed | 189 km / h (102 kn ) |
| Cruising speed | 178 km / h (96 kn) |
| Engine (s) | 1 × Lycoming O-360 (131 HP takeoff power) or O-320 (160 HP takeoff power) (Beta II) |
| Maximum range | 556 km (300 NM ) |
| Service ceiling | 4,267 m (14,000 ft ) |
| Maximum hover altitude | 2880 m (9450 ft) |
| Amount of fuel | 112 l (29.7 US.liq.gal. ), Including optional additional tank |
| consumption | 26.5 to 37.8 liters / hour (7 to 10 gallons / hour) |
| Empty mass (variant Beta II) | 417 kg (920 lbs ) |
| Maximum take-off mass (variant Beta II) | 622 kg (1370 lbs) |
| Width over runners | 1.93 m (6 ft and 4 ″) |
| Seats | 2 |
| Base price (as of 2010) | US $ 250,000 |
Comparable helicopter types
- Bell 47 (no longer in production)
- Brantly B-2B
- Enstrom F-28
- RotorWay Exec (Similar Size Kit Helicopter )
- Swiss 300C
- Cabri G2
Web links
- The manufacturer's website (English)
- Type approval of the R22 - EASA-TCDS-R.120 (PDF; 209 kB)
literature
- Eduard Kus: Test: Robinson R22 . In: Flug-Revue June 1980, pp. 36-39
Individual evidence
- ↑ Investigation report of the Federal Bureau of Aircraft Accident Investigation on the frequent R22 and R44 accidents ( Memento of March 4, 2016 in the Internet Archive ) (PDF)