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Some miscellaneous ramblings on the airbox.
As stated, your engine airbox depends on the year group.
My 1998 timeframe engine also has no brace. The only time a brace is nice on the non braced airbox mod (done sometime around 2010), is when using a thin silicone turbo discharge hose connected to the airbox. (The heavy double or triple braided black hose
supplied by Rotax on the old engines was quite stiff and combined with the carb sockets at the manifold and hose clamps kept the airbox on securely (nearly all the time with balanced carbs.) The issue with the airbox in the old days was it kept sliding off
the port carb due to oil accumulation. If you flew often, the oil thrown out of the turbo was but a wisp and if the engine was well tuned it stayed put. If you didn't fly often and the 2-inch hose became oil soaked, then the plenum hose to carb would slide
off (especially at full boost) and if the carbs were not well synchronized (read as "shaky engine") it slid off fairly often just when you didn't want it to. I found the used 914 I bought had carbs that were no longer a matched set any more due to some wear
in the piston throat, as the pistons were well out of sync. I bought two new matched carbs and with that carb change, proper tuning, and cleaning my airbox to carb rubbers, all stayed where put and the engine ran flawless now for 10 years. Even after I upgraded
the TCU to give me 40 inches takeoff power it stayed put.
If equipped with old oil soaked hoses or a thin silicone discharge hose, or you left your carb to airbox hoses get really oil soaked, it is prudent to clean your airbox to carb rubber hose with acetone or similar solvent to make them squeaky clean (or replace
them). (Washing your intake plenum out helps also.) To assist in security of a shaky engine, a couple of padded hose clamps and a piece of sheet metal could hold the airbox firmly to the ring mount to prevent slipping. Also, a couple of Adel Clamps and a
piece of tube and bolts could work also on the older manifold without welding on a bung like the new airbox has. In a pinch, a piece of safety wire on the port side to the ring mount frame at the upper block bolt was also OK at preventing the plenum from
slipping aft but only temporarily. A nicely made piece of .040 aluminum with a bit of a bevel for stiffness on the edges or a flute down the middle and nicely formed ends could in fact hold the box firmly in place and at the same time keep it from sliding
off. To remove the carbs for cleaning, or to flush the accumulation of turbo oil out of the plenum after setting a long time, it only required removing the bolt between the Adels the two carb clamps and it was free.
Once I had perfectly synchronized carb pistons and flew more often, I never again had an issue. Someplace in the shop I still have my Adel Clamps, a long bolt and tube just in case because I wondered about this new silicone turbo hose I added this year and
it's contribution to airbox security. Today my plane has sat for two years due to a wing delam repair and repaint, a number of upgrades and some other issues my old Classic has, however, today my procedure is to suck the oil out of the turbo cold side before
start if it has sat (for months) and it seems to run very well. I hope to get the motivation to fly it again this summer. It's too good of an airplane to just sit. My health is now pretty good, and I just flew a ride with a local instructor in a 172 and
will fly some more proficiency flights to get my air sense back and return to Europa Flying. My civilian CFI says I'm more than proficient enough, however, he has some learning to do.
There is a difference between currency and proficiency. I've only flown 2 hours in two years with 3 landings in the last 30 days which is not proficiency in my book. Now to take him out and wring out the 172 and get him
to understand why an airplane does certain things and as an instructor know how to rectify student mistakes.
Have fun guys, the flying season is now arriving. The spring storms will subside soon and adventure awaits...
Bud Yerly
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matronics.com> on behalf of Roger Sheridan <rogersheridan@gmail.com>
Sent: Saturday, April 6, 2024 8:21 AM
To: Europa List <europa-list@matronics.com>
Subject: Europa-List: 914 Airbox Support
--> Europa-List message posted by: Roger Sheridan <rogersheridan@gmail.com>
Hi Everyone,
I am refurbishing an XS 914 installation & am mildly concerned that the Rotax airbox/plenum seems to be only supported by the carb mount rubbers.
During a heavy landing there must be a lot of stress there!
On the 912S installation Europa support their lighter airbox with an aluminium strap to the engine frame.
Has anybody added such a support to their 914?
Grateful for any feedback from 914 operators.
Best regards,
Roger
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