Scaled flight testing supporting the development of radical new aircraft

Henk Jentink, Royal Netherlands Aerospace Centre NLR (The Netherlands)
Floris Bremmers, Royal Netherlands Aerospace Centre NLR (The Netherlands)

Abstract

Scaled flight testing can contribute to valuable reduction of risk and cost in the development of a radical new aircraft. The role of scaled flight testing in the aircraft development process is described, where it is essential that the relationships between the small-scale and full-scale results are properly defined. The validity of results of scaled flight testing for predicting the full-scale aircraft properties is addressed next.

A 1:8.5 scaled version of a typical large passenger aircraft was built, tested in the wind tunnel and flight tested. During the flight tests an accurate flight test instrumentation system measured the scaled aircraft flight parameters. Results of the scaled flight testing have been compared with full-scale test results which validates the value of the scaled flight testing methodology. In a next step the scaled flight testing methodology is applied to investigate and demonstrated the benefits of distributed electric propulsion.

The scaled aircraft has been rebuilt in the same shape but the jet propulsion is replaced by propulsion with six propellers. The development, manufacturing, wind tunnel test and taxi tests are described, flight tests still have to be performed. Finally the role of the flight test engineer in the scaled flight test campaigns has been compared with the role of a flight test engineer in a typical full-scale flight test campaign. The roles were chosen very similar and that worked out very well in these scaled flight test campaigns.