Tension gas struts play key role in light aircraft certification

Citation

(2008), "Tension gas struts play key role in light aircraft certification", Aircraft Engineering and Aerospace Technology, Vol. 80 No. 1. https://doi.org/10.1108/aeat.2008.12780aab.007

Tension gas struts play key role in light aircraft certification

Tension gas struts play key role in light aircraft certification

Industrial Gas Springs has played a key role in helping a UK company secure the certification of its revolutionary microlight – believed to be the first use of gas springs in an aircraft control system.

The certification of the WT9 Dynamic two-seat sports aeroplane was already well behind schedule when the UK Civil Aviation Authority (CAA) test pilot decided that the mechanical flap actuation system was too heavy to operate. Built in Slovakia, the entire aircraft would have to weigh no more than 256kg to receive the CAA's stamp of approval.

Manufacturer Yeoman Light Aircraft Company Limited (YLAC) urgently needed to find a solution. After considering a conventional spring, then a rubber bungee, the company's designers thought that a gas spring might hold the answer. The idea was that this would increase the forces for the first part of the flap selection, then “pay back” in the key later stages – but it still did not solve the problem.

YLAC Chief Engineer Tomas Prihoda concluded that what they really needed was a gas spring that worked in the opposite sense to the usual ones. After some web searching, he found a tension gas strut that would reduce flap forces throughout the whole movement range.

Prihoda designed the theoretical optimum solution, but the next problem was to obtain a lightweight strut, which complied with his exact specifications and was sufficiently robust for use in an aircraft.

“After searching around on the web, we were starting to despair,” explains Managing Director Nick Marley. “When we found Industrial Gas Springs, we felt that our prayers had been answered. Right from the start, IGS had a `can do' approach. They had informative material on their web site to help Tomas perfect the design and most importantly, recognised the urgency for quick delivery of a test strut. Two custom-made struts were delivered within a week of our initial enquiry.”

The test struts were fitted to the prototype aircraft overnight and flown by YLAC Test Pilot Tom Porteous the following day.

“It was brilliant,” says Porteous. “The flap selection was much lighter and our problem was solved – the struts worked exactly as we intended.”

This view was confirmed by the CAA Test Pilot, allowing the dynamic to receive its certification. YLAC immediately placed its initial order for 15 tension gas struts for production aircraft, which again, was fulfilled, in record time.

“We were very pleased to be able to come to the assistance of YLAC in getting their project back on track,” says Steve Woolcock, MD of IGS. “While we have supplied gas springs for installation on both civil and military aircraft, this is the first time one has been used in a key control system, and naturally I am delighted at the recognition of the quality and reliability of our springs that goes with it.”

Details available from: IGS, Tel: +44 (0) 20 8646 6595; E-mail: sales@igsltd.co.uk, web site: www.industrialgassprings.com