MBB Bo 105 Bo 105M (VBH)

The Bo 105M is the military liaison and observation version of the Bo 105 for the Heeresfliegertruppe, the German Army's aviation branch, which designated it VBH (Verbindungs- und Beobachtungshubschrauber, liaison and observation helicopter). The Bundeswehr ordered the type in 1974 as a light liaison and observation helicopter, a year before also selecting it as an anti-tank platform; 100 VBH and 212 PAH-1 were delivered to the army aviation units. Although it shares its family designation with the Bo 105P, the German Wikipedia stresses that the M was an entirely independent, unarmed series rather than a simple offshoot of the anti-tank helicopter.

Technically the Bo 105M was derived from the civil Bo 105CB, but with an uprated main gearbox and a tail rotor of higher thrust than the standard one. That dynamic system and the avionics later formed the basis of the PAH-1, which added a strengthened airframe, the Doppler radar and the weapon system. The FS 110 main gearbox (Flugsondergetriebe; the 110 refers to its 2 x 55 kpm input rating), initially fitted to the military M and P versions, eventually found its way into the civil CBS-5 in the 1990s. In army service the Bo 105M replaced the Alouette II in the liaison and observation role.

The data sheet displayed with the aircraft at the ILA Berlin Air Show gives its figures: five seats; two Allison 250-C20B turboshafts of 400 shp each, with the main rotor turning at 424 rpm; four manually foldable main blades and a two-blade tail rotor; a maximum speed of 270 km/h, cruising speed of 220 km/h and marching speed of 200 km/h; a ferry range of 320 km when empty; a climb rate of 8 m/s; an overall length of 11.86 m with rotors turning, a fuselage length of 8.56 m, a height of 3.02 m, a main rotor diameter of 9.84 m (76.05 m² disc area) and a tail rotor diameter of 1.90 m; an empty weight of 1,670 kg, a take-off weight with external load of 2,400 kg, a payload of 691 kg and 290 kg of fuel. The 250-C20B engine, rated at 298 kW, weighing 70 kg and measuring 1,036 mm in length and 485 mm in diameter, was built in Germany by MTU between 1979 and 1983 for the military variant of the Bo 105.

Until German reunification the VBHs served with the staff squadrons of the army aviation commands, the helicopter squadrons of the divisions, the Army Aviation Weapons School and one army aviation regiment. After reunification and the restructuring of the Bundeswehr they were redistributed among the medium transport helicopter regiments, Army Aviation Liaison and Reconnaissance Squadron 400 and the Weapons School, where they served as training helicopters for future pilots. They carried the tactical serials 80+01 to 81+00.

The Bundeswehr's Bo 105Ms were retired in 2004, which opened a capability gap in liaison and training. Since the PAHs still in service had accumulated fewer flying hours, it was decided to convert them into VBHs: between 2006 and 2014 Eurocopter converted 67 Bo 105 PAHs by removing the weapon system and refitting the rear bench seat, under the new designation Bo 105 P1M; these flew until their withdrawal at the end of 2016 at the International Helicopter Training Centre in Celle. Twelve surplus airframes were meanwhile remarketed as the Bo 105E-4: according to the German Wikipedia this is the commercialised version of the Bo 105M, technically different from it, whereas the English Wikipedia describes them as overhauled Bo 105Ps. In early 2000 the Federal Office of Defence Technology and Procurement (BWB) and Eurocopter signed a framework agreement for their return and remarketing; the first E-4 (s/n 5087) flew at Donauwörth on 25 January 2007 with test pilot Rene Nater and inspector Bernhard Röper, and on 24 April 2007 the first two of the twelve landed in Tirana after a delivery flight, to serve in Albania as rescue, VIP and liaison helicopters.

One Bo 105M survives as a monument: since 2011 it has formed part of artist Alfred Gockel's installation at the Kamen motorway interchange (Kamener Kreuz), stripped of its interior and painted in the characteristic yellow of ADAC rescue helicopters.