Mods
 2005.10.21
 

At Oshkosh 1992 I saw a fellow wearing a pale blue maybe turquoise VariEze RACE shirt and talked him out of one. (This Oshkosh it was autographed by Mike Mellville and Brian Bennie). Rob Martinson has since opened many doors to me, including his Denver home for a stopover on the way to Jackpot. He is another fellow I decided I wanted to be like when I grew up.

Rob asked if I was building or flying. When he found out about my garage full of new-to-me VariEze parts he hustled us over to Charlie Airesman and his pristine VariEze. For the next hour or so Charlie threw back the curtains on a whole new world of creative possibilities.

To that point I was sold out to Burt’s original intent including the A-75 engine. But that was pre-Martinson and Airesman. The only really negative experience with them since has been to chase them from Denver to Jackpot. I wasn’t worried how many minutes I was behind, but rather how many states.

Now sometimes when spotting Charlie the first time across the ramp at a fly-in he hollers “How fast are you now?”
I holler back “Three hundred knots!” “…On paper.”
“Good,” he replies, “I’m still thirty knots ahead of you…on paper.”
And probably in reality.

Besides Rob and Charlie I bumped into Bruce Tift, Gary Hertzler, Ken Swain and his scimitar prop, Mike Mellville, and others, and had been able to get their opinions of some improvements I had in mind. With the early appreciation of what Burt had accomplished with weight and efficiency, no mod was approached lightly.

If the plans for the first little 390 lb VariEze would have been offered I would have jumped on that one. The plans for N95BJ were ordered while I was flying for the Marines in Japan, on the day they were first offered. Fifteen years later I turned 40 and realized that yesterday I was 20 and tomorrow I would be 60. Time to move. I had been frustrated waiting to build, the typical otherwise happy guy, living in quiet aviation-deprived desperation. Once the parts were in the garage I was fine.

This pile of boxes had original shipping dates of 1982. Evidently three guys in California bought kits together and two got started and flew. The third set of parts passed through six or seven hands on the way to my garage. It took three months at the kitchen table pouring over the plans to update and get familiar with everything. The number of unknown parts got smaller and a box of not to be used parts got bigger. Nose forks and gear retract rods and other such improvements. I had kept notes of builder and flyer pros and cons heard over the 15 years that resulted in some “modifications” as they are referred to, leaving “improvements” to RAF.

The initial intent on lightness and simplicity came to include operational functionality, ideally with no penalty. Like that free lunch.
Removing or fitting the cowls was often mentioned. At an Oklahoma fly-in one fellow wrestled with cowl fit for a good while and finally just put two screws in his pocket before departing. Flying helos, especially doing maintenance test flights on them, I liked to see everything. Same if I built a plane, it would need easily installed and removed cowls.

My first set of cowls had overlapping flanges. They were secured with internal canopy type hinge groupings around the perimeter with pins on cables. This worked well but the metal hinges did start to show signs of wear. And it occurred to me one night, after enough epoxy fumes, that the cowl attachment didn’t need all the complex multiple locks, just one long one.

New cowls now have a tube perimeter flange. Using observations from the first set, the cowls now slide in place and the interlocking flange takes advantage of lift and pressure. Several robust rods ensure sound attachment, and several stainless pins hold the cowls in place on the ground before air loads take over.

At the time the plane was painted last year there was a list of about 35 unique elements on the plane. The biggest are the slightly lowered (LongEZ) cruise attitude, the extended strakes, level wings, downdraft cooling, rear seat sump and 35 gallons total fuel.

The consoles are condensed (closer to the walls) and the leg holes in the instrument panel are the same as the LongEZ. It would be really hard not to have the front seat elbow room that the extended strakes provide. These and others are described in more detail in Featured Aircraft on the home page.

Recent changes
When considering the replacement 0-290 I jumped at the chance to address two areas of interest:
Lean of peak cruise, and
To head off expected high oil temps.

With the new engine the main gear strut was remounted with the axles now two inches aft at the LongEZ location. Minor CG change, with about the same ground balance and nose rotation speed as before. Also gives a lower drag strut angle.

The carb location is transparent so far.
Plenums and CHTs are good, as before.
LOP cruise tests at altitude are yet to be done.
The oil temp is stabilized but still too high.
As with the airframe before, cosmetics haven’t yet been addressed on the new engine components. Several elements proved their worth and have been further optimized. Several others have been ceremoniously banished to the dusty memory box.

With the previous 0-235 the downdraft conversion immediately gave good CHTs. But on warm days the normal oil cooler setup required that the power and climb be “managed”. In other words sometimes the power had to be pulled back before I wanted to, and step-climbs had to be used to allow the oil to cool off several times on the way to 12K

The 0-235 temps were finally tamed and the plane could be run as long as you wanted at full power, low level or climbing to 12K. I thought I was just getting to where everyone else was.
A friend converted to DD Plenums and after flying them a few hours, mentioned that he thought I was lying about my cool CHTs, until he saw his doing the same thing. A couple more stories here, maybe later.

The final oil temp key was a little cool air inlet into in an aluminum fence enclosure around the oil pan. That success led to the lower plenums.

Expansion of the 0-290 envelope this summer has shown good indications overall. Minor distractions have kept me from dancing an appropriate jig over the things that have proven good. That’s coming.

Eight years ago I had a full building experience but a well proven broken-in engine. This time it was my intent to be fully involved with the engine. To say that I am ready to be back to the 15 to 20 sunsets a month would be an understatement. Interestingly, immediate suspicion of the new engine setup for causing erratic operation has been inefficient. Components unrelated to the mods have taken more than their share of the time. Two examples:

Several bad oil temp gauges provided misleading indications. Becoming overly adept at calibrating new temp gauges was not one of my objectives but it does go faster with practice. Aircraft Spruce was fair with me.

In the early summer a leaking intake valve guide caused fouled plugs and power fluctuations. It was taken in for repair and I then eliminated the guide and fouled plugs as a factor, too soon. Naturally when erratic power showed up again a number of other causes were also looked at, with the problem being found in the last place you look.

Yesterday, after conferring with several A&Ps, the cylinder was taken back to the shop again to confirm the condition of the guide and to check that the correct guide had actually been replaced the first time. Fortunately my first flight experience with the 0-235 was smooth and provides a good pattern. And hope.

Several folks have said the temps just get high in hot weather, that’s just the way it is, and that I shouldn’t even try, just give up on it….
Probably not.

Along the way to getting the oil cooling work done and written up, am making a note and maybe an image or two on the cowl attach detail, and some thoughts and observations with the downdraft cooling.
One experience already waiting in the wings has to do with the first test flight with the 0-290, a strange erratic whirring noise, and the finely honed troubleshooting skills used to resolve it. Ha.

Some of my favorite experiences in the VariEze have to do with the carefree wide open power use with the 0-235. I won’t go into them just yet, rather,

I will just hope for all of us, more fun flying with the impression of being fast and intelligent, with the outcome so good that we don’t even have to say anything.

Still trying to catch up with you guys…
Bill James, Fort Worth VariEze

Contact Contact Bill
  EZ Home