Tire Changes for Zenith Aircraft

Several Zenith aircraft have wheels with one-piece rims.

Changing the tire of such a wheel is difficult, since there is no easy way to clamp down the rim. We have that case for the 8 in. wheels of our Zenith 601HDS, where the rim has delicate cast spokes. 

This post describes a fixture that makes the task easy. It holds the wheel in place while we remove or install the tire with two spoons.
Here are the steps for making the fixture.


Use 3/4 in. plywood. Make the piece large enough so that you can hold it down with your feet or knees.

Three Support Blocks

Cut three triangular support blocks shown in the above photo from a short 2x4 piece. Attach them to the platform from below with one drywall screw each.

Glue a patch of rubber shelving material on top of each support block. The soft material assures that the blocks do not scratch the paint of the rim.

Center Bolt and Spacers

The center bolt has the same diameter as the axle holding the wheel in the airplane.

For the mounting of the rim,…

Rotax 912 Engine: 2,000 Hours in 25 Years

The Rotax 912 engine in our plane, a Zenith 601HDS, has reached an important milestone. Over the past 25 years, it has run 2,000 hrs without major repairs.
It's appropriate to reflect about this performance and muse how this is possible. After all, when we bought the engine, in 1994, the suggested TBO was 1,200 hrs. 

Since then TBO has gone up, first to 1,600 hrs, and more recently to 2,000 hrs. Of course, those increases apply to later engines, not to our early model.

Let's see how the engine performs after all this time.

Performance after 2,000 hrs

Compression is 78-80 lbs/ on all cylinders. Oil consumption is less than 1/2 qt per 25 hours. 

During each oil change, we cut open the filter and look for metal. There is almost none, just three or four tiny specks. Essentially, the engine shows no sign of wear.

The engine performs well up to the legal limit of 14,000 ft MSL for flight without oxygen.

When flying without passenger at 14,000 ft, the plane can still climb at 250 ft/mi…

The Illusion of See (Other Aircraft) and Avoid (Mid-Air Collisions)

Until recently, collisions between aircraft were rare, supposedly because pilots used See and Avoid.

But now ADS-B information displayed in our cockpit on the iPad reveals that this explanation just wasn’t correct. There were hardly any collisions because the odds of two aircraft meeting in the air were next to zero, due to the small volume taken up by two aircraft and the comparatively huge volume of available air space.

But “next to zero” does not mean “zero,” as we found out during a recent trip, where in two instances, on the same day, we were mighty close to a midair collision.

So how did we avoid these potential collisions? We saw those airplanes on our iPad, since we now have both ADS-B In and ADS-B Out, and thus are continuously served with the location and speed of all aircraft within a so-called hockey puck surrounding our aircraft. It has a diameter of 30 miles and extends above and below us for 3,500 ft.
The ADS-B systems sends to us not just information about aircraft that al…

Faulty Rotax 912 Alternator Wiring

During repair of the motor mount, a major project, we discovered that the wiring of the integral alternator supplying power to the ignition module and the voltage regulator/rectifier had badly corroded.

The above photo shows fragments of the wires going from the stator of the alternator to the voltage regulator/rectifier.

Next is a photo of the wiring going from the stator to the ignition module. Here, too, the insulation has broken off and the wires are badly corroded.
Surely the damage must have been building up during several years. How could we have missed it during the annual inspections?

The Answer

There are two places where the wires are visible: At the voltage regulator/rectifier, and at the ignition module. These wires looked okay until a recent major repair of the motor mount, where everything firewall-forward had to be removed.

At that time, the wiring had to be disconnected from the voltage regulator/rectifier. Right then, the insulation turned out to be brittle, broke off, and …

Make Your Own Labels Free and Without a Label Maker

You can make your own custom labels, displaying any text, even pictures, without use of a label maker. The labels have a waterproof surface, are self-adhesive, and stick to virtually any surface. The cost of each label is just a few cents.

The above photo shows a label we made in 2016 for our airplane. It shows no sign of aging. In the meantime, we have become more adept at the process and produce a more accurate label boundary. We include the example since it is the oldest label we have made with the method.

Another label, made in 2019, explains the readings of the Hobbs meter in our airplane. 
The label tells that one must add 1,950 to the indicated Hobbs time to get the total in-service time of our airplane.

Here is a panel label for Piper Cubs. Years ago, we saw a Piper Cub with that text taped to the panel. Clearly, the owner had a great sense of humor.
Needed Equipment

The only equipment needed for production of such labels is a computer with Microsoft Word and a printer. Yes, that…

uAvionix TailBeacon: Installation and Testing

The uAvionix TailBeacon is a low-cost device that satisfies the ADS-B Out requirement kicking in on January 1, 2020. 

The TailBeacon piggybacks on any Mode C or S transponder, and thus avoids purchase of a much more expensive ADS-B transponder. 

There are two TailBeacon versions: the TailBeacon TSO for certificated aircraft and the less expensive TailBeacon EXP for experimental aircraft. 

We bought the EXP version for our Zenith 601HDS, N314LB.

uAvionix also offers an alternate ADS-B Out module: the SkyBeacon. It uses similar technology, but is installed in a different part of the airplane. Details on this below. There are two versions: TSO and EXP.

This post covers why we selected the TailBeacon and how we installed, tested, and evaluated it using the FAA ADS-B Performance Report. It's easy to adapt the process for installation of the SkyBeacon.

ADS-B Out Requirement

Starting on January 1, 2020, every airplane in the US must have ADS-B Out if flight is conducted

– within class A, B, or C…