The Eurofox Project
I think this was a first at YGC. The T21 is ‘a bit’ draggy and quite heavy with 2 pilots. With the air temp a pleasant 26 degrees, we towed at 55-60 knots IAS in the tug with 1/2 flaperon. Engine T’s and P’s stabilised at the top of the oil T green arc, and coolant/CHT 100 degrees C.
Take off distance off the short runway 24 was the same as a K21, but at the lower tow speed the rate of climb was noticeably lower, and the thermals were a big help. The lower RPM (at lower climb speed) means that power output is down on that pushed out at between the 5350-5400, and this was particularly noticeable with the T21 on the back.
The experience made a change from towing slippery competition ‘loads’, and we’re still learning.
The YGC EuroFox is coming up to her next 50 hour check after a thorough 150 hour check up last month by Inspector Mark. The 50 hour ‘cycle’ of checks means that the Rotax servicing requirements are easily fitted into the LAA system. Mark carried out compression checks and arranged gearbox torque checks in addition to cutting open the oil filter to check for nasties; G-MOYR got a clean bill of health and will get a new set of spark plugs when we do the 50 hour check this week (different plugs to the 80 hp 912 noted!).
We are achieving monthly hours of nearly 50 on our EuroFox, and are delighted with our (not so) new tug. She is a delight to fly and operate, and straight forward to work on and maintain in pristine condition. G-MOYR has now topped the 900 aerotow mark, and will probably account for over half the tows at Sutton Bank this year. Climb rates with the big 2-seaters are slower (30 secs to 1 minute to 2000 feet) but the retract winch and the fast descents made possible by the Rotax 912 make for noticeably quicker turn round times. 1000 foot training tows (glider circuit training) give launch rates quicker than winch launching! Next year’s cost review may well result in further reductions in launch fees.
…..and we have ordered another!
G-MOYR is living up to expectations, and “doing everything it says on the tin”. Integrating the EuroFox into our Pawnee/Super Cub tug fleet has worked out nicely. By chance, our Cub suffered an undercarriage collapse as we were completing the Permit flying, so EuroFox slotted straight into the gap! The new tug’s towing performance is better overall than the Super Cub - 30secs to 1 min slower to 2000′ but much quicker getting back on to the ground, leading to noticeably quicker turn round times between tows. Average fuel consumption for aerotowing a mix of 2-seat and single seat gliders is working out at 2.7 litres of UL91 to 2000 feet. YGC towing charges reduce on 1st April, and we are introducing EuroFox training tows to 1000 feet for 2-seat training and early solo flying. Towing pictures to follow when my camera comes back from the menders, it never recovered from being dropped on the workshop floor during the build!
The weather has slowed the conversion process down somewhat, but G-MOYR has risen to all the challenges thrown her way. With 60% of the airfield waterlogged and unusable much of the aero towing has been off a soft runway 24, or from the footpath side of runway 20 opposite the caravans. Neither run is longer than 600 metres but EuroFox tows the DG’s and K21’s very safely; as the instructors and glider pilots get used to the tug taking off before the glider, the whole procedure is becoming safer and more routine. The turn round time between tows is working out slightly quicker than the Cub/Pawnee operation.
In order to avoid carrying unnecessary mass into the air, we are recommending using the left tank as reserve with about 10 litres fuel and the tank cock off, and using the right tank (40 litres) as the main supply to the engine. That fuel load is good for about 15 tows, and 2 hours towing at a stretch is enough for anyone before a cup of tea becomes a safety essential!
As a result of feedback from our tuggies we are going to move the heel plates forward so that boot heels rest on the plate not the carpet (I think it must be me that’s deformed, having located the plate position during the build!), and remind everyone that there is no need to attempt to force the doors open during the pre-take off checks using the door frame; just a visual check of the latch at the bottom is all that’s required (’cos we’re getting a bit tired of ‘rebuilding’ the doors each week). Gorilla (Pawnee) flying techniques are not required, and the bigger tug pilot can remove the seat cushions to give more cockpit space if required, using a thin shock foam one instead.
Let’s hope the weather starts improving soon. G-MOYR can then really show us what she capable of as a glider tug, and to the tug pilots who have not flown EuroFox yet - you will love it!
10 of YGC’s tuggies have now converted to EuroFox, and are now finessing their skills on unsuspecting glider pilots! G-MOYR has just reached 25 hours on the engine, so it’s back into the workshop for her first check over. This photo was posted on the BGA’s Facebook page.
We also had a very interesting set of barograph traces sent in to the Office. One of which illustrated the dramatic effects of atmospheric wave action on an aerotow climb profile. The other was a ‘normal’ tow for comparison which appears to have avoided the wave completely (or managed to fly in the updraft!). The ‘wavey’ trace was from a EuroFox tow flown by a ‘first-timer’ - obviously working hard there, Les! These early days with our new tug have been a very good test for the EuroFox; towing the heaviest 2-seaters in light winds off soft, wet ground has been quite challenging, but she has coped really well.
The north eastern end of Sutton Bank is a soaking wet sponge, so we have been aerotowing from the footpath side of runway 20 which is the ‘driest’ part of the airfield. 2 more tuggies have now aerotowed with G-MOYR, and have returned commenting favourably on her performance and handling.
EuroFox’s light footprint is paying dividends on the soft turf - as the glider undersides get ‘artexed’ with black Yorkshire mud, the tug only gets easily removed mud pellets that flick off the tundras. Compared with the Pipers the ground ride is very comfortable, and the visibility from the cockpit is very good.
Now the builder has been banned from the left seat, it has been good to see our creation flying from outside the cockpit. The aircraft is amazingly quiet and looks super in flight. Early calculations indicate that the EuroFox tug ‘does just what it says on the tin’. Having bulked the aircraft with full fuel and ballast to MAUW, we topped off the tanks after a 45 minute flight test, 18 aerotows, and 20 minutes of famil flying with 45 litres of UL91. The tanks were probably about 10 litres down from full up after refuel, so 1 hour flying and 18 aerotows on 55 litres is jolly respectable - that’s roughly half of what you would put in a Pawnee after 12 aerotows!