PROBLEMS WITH EUROPA XS 912ULS INTAKE WATER INTRUSION
As many of you know, I install very few 912ULS engines as I believe that the 914
is the ideal engine for the Europa XS. That said, for the pilot not interested
in flying high and fast but a little lower, with lower up front costs and
fewer maintenance headaches, the 912UL and 912ULS are very acceptable
substitutes.
Particularly the 912ULS of 100 HP when equipped with a constant speed propeller.
It is only slightly slower in cruise, lighter, has excellent takeoff
performance when operating at density altitudes of less than 3000 feet, and is
reasonable at cruising altitudes of 7000 feet or below. Granted it has been
eclipsed by the new 912iS engine, but it is still much more cost effective than
the newest Rotax injected computer babies and can be maintained with simple
hand tools.
I recently had a second hand owner of a nicely built Europa XS powered by a
912ULS,
which was built in accordance with the Europa manual, have to store his aircraft
outside on the airport ramp for a year in central Florida. Time passed
as he was busy with debilitating medical difficulties. I saw the aircraft
derelict
and looking like a mildew experiment. I decided to do some checking.
I last saw the aircraft around Christmas time, however, weve had some 30 +
inches
of rainfall and extremely warm weather since then.
I received the OK from the owner and airport and on initial inspection, I could
not pull the prop through. I opened up the cowl, and found the #1 and 3
cylinders
had water in them, the airbox had some black mildew on the starboard side
which plugged the 1/8 inch drain hole completely. This resulted in the
starboard
carb float bowl filling with water. The entire 1/3 carb had a redish brown
film. The redish brown film was a fungus common here in Florida which grows
on the inside surface of fuel tanks in the steamy summers. Further inspection
showed the intake manifold slime covered also. The owner agreed to allow me
to transport the aircraft back to the shop to dry it out and perform an engine
and airframe condition inspection. After washing the exterior, upsetting many
insect colonies, removing the carbs, pulling the plugs and lower oil return
line, I removed a half cup of water from the cylinders and about the same from
the bottom of the crank case. Luckily, the water in the crankcase simply flowed
to the bottom and was covered by the settled oil. The bore scope revealed
the pistons valves rings and cylinder walls were remarkably clean. His gearbox
on removal showed no sign of water intrusion and looked like new. He got
lucky.
I am now looking into what can correct this from happening to others with stock
installations. Many of you owners have had similar comments over the years
about
the NACA duct opening on the Europa XS 912 UL/ULS allowing water to flow
into the intake box. For short time outside tie down, the drain holes of 1/8
inch should be fine to drain most of the water that could possibly seep in. But
to prevent water intrusion totally when tied down, the solutions were many
and varied. For some builders you simply:
1. Never leave your aircraft outside in the rain. Obvious, but not always
possible.
2. Cover the aircraft with a rain proof cover when tied down. Obvious for
lengthy
tie downs. However, for the average cross country flight, these covers can
be quite bulky. The Europa does not have a sail locker in the bow. The covers
are a bit pricey also.
3. A plug can be devised to block the inlet and most of the water. An
inexpensive
fix if done right.
4. Tape over the hole for tie down.
5. Fabricate a 914 style inlet and ducting to avoid the NACA rain inlet
problem
completely.
6. Make up some sort of water catch to drip the water away from the filter
inlet hole.
For the diligent builder who follows the instruction without modification or the
second hand owner who must tie his aircraft down in a rainstorm, is there a
solution other than plugs and tape that can be easily done during an annual
condition
inspection to relieve him of the fear of a waterlogged engine?
Nev and I consulted on this some years ago and I've had a few changes in how I
do it but my ideas are not the only ideas.
I will provide some construction background and diagrams on why this is an issue
and perhaps some ideas of my own soon, but I am interested in your solutions
also.
Best Regards,
Bud Yerly
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