Pilatus B4 - PC 11

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Pilatus B4, inverted

The Pilatus B4 is probably the best-known Swiss glider world-wide. Less known, however, is the fact that it was originally designed in Germany. In the mid-1960ies a trio of young engineers designed it for a German businessman named Gert Basten; hence the "B". He had two examples built; one with fixed and one with retractable wheel. The original German type certificate is from November 1970.

Pilatus acquired the rights to the design and developed it for series production. There, it was given the designation PC 11. The Swiss type certificate was awarded in June 1972.

The original design was not stressed for aerobatics. Pilatus reinforced the wing roots and the empennage, so their series version was certified for "basic" aerobatics and cloud flying. In the following years,the versions PC 11A, which is certified for rolls and inverted flight and PC 11AF, which may also do flicks, were developed. The Swiss Federal Aviation Office granted type certificates for these two versions on 31 January 1975.

The B4 enjoyed an ever increasing popularity due to its rugged construction and ease of maintenance. Between 1972 and 1978 Pilatus produced a total of 322, many of which still fly on all continents.
In 1980 Pilatus sold a licence to the Nippi Corporation in Japan, which produced a total of 13 gliders. In 1983 the Japanese even tested a B4-two-seater!

B4T

When Pilatus terminated the technical support for the type in 1994, Dietmar Poll took over the entire stock of spare parts. Holder of the type certificate, however, is still Pilatus AG.

Compared to the newer aerobatic glider types, the B4's operating limits are rather restrictive. At the relatively slow roll rate of the B4 and with its VA = 163 km/h and VNE = 240 km/h, figures with rolls on vertical or 45 inclined lines are difficult to fly within the limits.
Unlimited sequences as they are flown today are simply beyond the scope of this glider.

In Advanced, the B4 is still competitive, but the pilot must always be aware that his safety margins are much narrower than for instance with a Fox.
In 2010, the young Swedish B4-pilot Johan Gustafsson won the first World Advanced Glider Aerobatic Championship against 30 competitors who mostly flew Foxes. The following year, he was still able to finish 8th against a much stronger competition flying Swifts and Foxes.

B4 SE-UME

Jochen Reuter, one of our aerobatic instructors with many years of experience on B4s, has written down some useful hints for new B4 pilots. Here we have a translation for our English-speaking friends.

 

Technical Data

wing span 15 m
wing area 14,05 m²
wing section NACA 643-618
length 6,57 m
empty mass 240 kg
flying mass 350 kg
safe loadfactors +7,0 / -4,7
manoeuvre speed VA 163 km/h
maximum speed VNE 240 km/h
minimum speed VS 60 km/h
best glide ratio 35 at 85 km/h
minimum sink rate 0,64 m/s at 75 km/h

Sources:
"Segelfliegen" 3/2012
German LBA-Specifications Nr. 266 dated 16.09.1982
Swiss specifications No. S 43-02 by the Eidgenössisches Luftamt, dated 30.11.1979

 

last updated, 03-2017

 

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