After 6 years my XL was certified in July, 2011. As of today (Jan 2012) it is over half way through phase I flight test.  I expect to complete flight test and enter phase II in the Spring.

I had a number of small problems in flight test.  Most of them have been resolved.  The primary issue was engine cooling (Jab 3300).  Other problems included the engine cutting out from a loose carburetor and a flat nose wheel from underinflation and damage to the tube when the tire rotated and deformed the stem.

The biggest problem now relates to the complete lack of yaw stability and similar lack of roll stability in flight.  That means the plane doesn't really want to fly straight.  My first attempt to deal with this was to add a white line on the top engine cowl to identify exactly where straight ahead is.  This helped.  My second attempt was to add a set of "Strakes" on the lower rear fuselage.  This also helped.  It still has no stability but the strakes seem to make it more natural to go straight ahead.  They also provide a surface to increase drag when a small forward slip is used on landing approach.

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Comment by Micahel Lynn Love on February 12, 2013 at 1:11pm
On my Ch601HD it has a nose wheel that is 1.5" X 8" cast aluminum with a 5/16 axile, and a Manco 2 ply nylon tire 4.80 - 8 max rating 745 lbs. Is there a replacement for this junk. It must fit the current fork and prefer same axile, I'd just like a split half wheel to make it easier to replace tire and tube.
email mllove@netzero.net
Thanks
Comment by Paul Mulwitz on December 16, 2012 at 11:51am

Phase I flight test completed 9/26/2012.  Phase II now active, but weather has prevented much flight.  The weather around here (Pacific NW rain forest) should clear up around May 2013.  I plan to do some real cross country flying at that time.

All problems fixed in Phase I except lack of yaw stability.  That seems to be inherent in the design.  There is no vertical stabilizer because of the full flying rudder and no portion of the fuselage side is parallel to the line of flight.  It seems the plane is just as happy flying +/- 11 degrees in yaw from straight since it presents the same cross section to the air flow in any of these positions.  This is more of an annoyance than a problem.  The plane flies fine - it just doesn't care whether the nose is going straight or somewhat left or right of straight.  The only time this is a problem is on landing when it is nice to have the plane pointing straight down the runway while flying straight down the runway too.

Air speeds for cruise can easily exceed 120 KIAS with full throttle on the Jabiru 3300 but this is not very comfortable unless the air is very stable.  Any turbulence is very uncomfortable at this kind of speed.  Normal cruise is more like 110 KIAS with engine set around 2700 RPM.  I found takeoff with half flaps to work best.  No flap takeoff works fine while using more ground roll but full flaps seems to lift off before there is good control of pitch and yaw.  Landings work best with full flaps.  No flap landings work fine but touch down faster and use more runway.  Final approach speeds around 60 KIAS or a little less work well.

The instrument panel has worked consistently during phase I.  Dual Dynons with HS-34 gives excellent flight and engine condition indications along with easy navigation with combination of Dynon HSI display and choice of either VOR from Garmin SL-30 or Garmin Aera-500 GPS driving course and deviation information on HSI.  Garmin transponder makes the plane suitable for VFR operation in any US airspace - at least until 2020(?) when ADS-B will be required.  Radio frequencies can generally be set into the Nav/Com radio from the GPS just by touching the line containing the frequency in the GPS database.

This should be a fine cross country travel plane with just the pilot and baggage or two full sized Americans and little or no baggage.  I haven't really checked fuel consumption yet but I expect around 5 GPH at 110 KIAS to work.  I didn't do a formal calibration of the airspeed indications, but the GPS seems to indicate the same ground speed as the airspeed indication when there is no wind.

I built and installed a Lift Reserve Indicator.  It seems to work fine, but stalls don't include any real break.  The plane goes into a steep sinking condition around 45 KIAS or a bit less but the nose doesn't drop.  The LRI does a fine job of showing safe airspeeds - especially in low speed turns as are common in the traffic pattern.

I don't know if I will keep the plane or sell it if the FAA approves the increased plane choices for those of us flying without a third class medical certificate.  If they go as far as the Australians with a gross weight limit rather than engine horsepower limit as proposed by EAA/AOPA then I might trade the Zodiac on a C-182.  That way I can actually take my wife and baggage cross country all at the same time.

Comment by Jacky Winters on December 16, 2012 at 11:13am

How did the remainder of the flight testing go and how was phase II?

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