LIPNUR Belalang
The LIPNUR Belalang () was a military trainer aircraft built in small numbers in Indonesia by LIPNUR in the late 1950s. It was essentially a Piper L-4J Grasshopper converted to give it a low wing. The NU-85 prototype flew for the first time on 17 April 1958 and the first production of NU-90 took place in 1959. The aircraft was operated by Indonesian Air Force. Indonesian Army and Indonesian Civil Aviation Institute at Curug, Tangerang also used this aircraft. Design and development In 1949-1950 period, the Indonesian Air Force (then called AURI) received around 60 Piper L-4J Grasshoppers from Royal Netherlands East Indies Air Force as part of the transfer of sovereignty. AURI used them as liaison and primary trainer aircraft. In 1957, AURI decided that their ex-Dutch L-4Js, which were powered by 65 hp Continental O-170, were already ageing and needed to be replaced. The L-4Js also has high wing so its aerobatic performance is very limited. Nurtanio Pringgoadisuryo, head of AURI’s Air Engineering Maintenance Depot at Andir airfield in Bandung, decided to modified the ageing L-4Js as it can be developed rapidly and with low technology so that the production cost is cheap. An L-4J then is modified