Engine bay
Instrument panel
Towrope winch conduit and guillotine

by John Gwyther on behalf or the eTug evaluation sub-committee: R. Dorning, P. Carey and R. Pugh
Photos by Robert Dorning

As part of its longer term strategy to secure more affordable launch capabilities, GCV is negotiating for a 12-month trial of a Pawnee fitted with General Motors LS1 V8 347 Cubic inch (5.7 litres) capacity, all-alloy automotive water cooled engine driving a three blade composite 84 inch diameter propeller.

Known as the eTug, VH-CUR has been developed by a syndicate in NSW with a goal of using automotive engines and fuel for glider launching. With much cheaper engines and lower cost fuel and burn-rates, it offers the potential for significant launch cost reductions if it does what it claims on the box. A water-cooled engine also offers the opportunity for shaving time off the descent as there is much less chance of shock-cooling the cylinders. More information about the eTug project can be found at: [GFA Website].

On its first trial at Benalla on Saturday May 2 the tug performed a series of tows whilst the owners oversaw the endorsement of Bruce Salter into the aircraft. On one of those tows, the eTug towed an IS28 to 4,800 feet and returned to the airfield in 9 minutes.

The eTug has operated as a tug at Lake Keepit Soaring Club over the last few years and has accumulated over 300 flying hours to date. It has recently had modifications made to the fuel system and has been issued with a fresh 100 hourly maintenance release by engineers at Scone NSW prior to delivery to Benalla.

The reason CUR has been made available to the GCV is that the owners would like to accumulate further hours and data for the type certification and also, in the words of the eTug Group "to see the aircraft flown at a club with GCV's profile and reputation. We think that such a demonstration of eTug's capability and economy is most valuable."

The aircraft operates in the Experimental category with a Special Certificate of Airworthiness that was issued in 2007 by Steven Dines Aviation Services, so some operating restrictions will apply; tug pilots and members will be advised shortly.

Our goal for the trial is to evaluate its operating effectiveness, efficiency, reliability and performance. If it achieves what Lake Keepit has experienced, then we could expect to shave 1 - 2 minutes off the typical 2,000 launch with some improvement in launches per hour.

The committee has debated how to charge for this during the trial, given its much apparent lower operating costs. In the end, we've decided to charge the same tow rates as the other Pawnees and to direct any surplus over our normal targeted operating profit margin into a future launching asset account. Members should get an immediate benefit in slightly shorter tow times. The Club will incur some set up costs; for example, it runs on 97-octane so we will need to acquire fueling equipment, which will be funded from this account.

At the end of the trial, the aircraft will return to its owners and we will have to decide whether we would order one ourselves. There is a lot of work the syndicate has to do to be able to offer us one and we would probably have to send them one of ours to convert. We will also use the time to look in more detail at other launch options, such as Light Sport Aircraft experiences at other clubs and the PIK-27 tug design, one of which is being built in Queensland.

This is a very interesting trial and we look forward to seeing how well it performs. Basically, we want to accrue as many hours as we can during this time so we can feel confident we know exactly how it will perform and what it will cost to run. Whether or not we proceed with buying one is probably 18-24 months away.

The eTug at Benalla