SonexBuilders.net

After seeing the new "B" model at Sun N Fun, I knew I just had to do the upgrade. Luckily I was early on in my build so the required changes are minimal. Sonex says that the B model Waiex they built weighs exactly 700 pounds as it sits with paint and all of the options and avionics they installed. Since I am doing polished, I am hoping to be about 25 pounds lighter ( using the numbers stated in Jeremy's weight and balance video from a couple of years ago) plus the options but I'm about to describe. I also understand that the Jabiru 3300 that I intend to use is almost the same weight as the turbo aeroVee so I'm thinking I've got a pretty good comparison. While in Oshkosh a couple of weeks ago I went ahead and purchased the Rotec liquid cooled heads, Mark II throttlebody, "real" alternator conversion and secondary electronic ignition. I have been weighing each and every component of all of these additions and I've calculated and estimated additional weight with fluids of about 20 pounds For all of the Rotec options with certain assumptions based on documentation for the deducted weight of the heavier air cooled cylinder heads and the removal of the stock alternator. I am also looking at the lightest 500X5 4 ply tires and the 6 inch tail wheel with hopes of still being at or about 700#. I am sure I will be a little forward CG of the factory Waiex B because I am exchanging paint weight for engine upgrades and I will install the earthx battery in the tail to help offset this. Oh, and before I get crushed for going with LCH, my decision was based on many conversations with 3300 owners and the comments they made about the difficulty in maintaining CHTs when climbing at max rate for substained periods of time. I accept the additional weight as an acceptable compromise to being able to not be "vertically challenged" in flight.

Any thoughts or suggestions from the folks would be appreciated

Hi chris ,
Nice to meet u chris on the flightline. Good luck w all the mods. The only one i never researched was the rotec alt kit. Will it clear the mount? I know the camit was designed to clear a legacy sonex jab mount. Bravo on the b conversion. I
have the plans and wing conv. Kit.
WaiexN143NM
Michael

Also chris,
A little wt. up front will help. Before you run all the battery wires to the back and install battery back there, try a w&b with the battery up front. Calculate with your wt. the cg location. If u can i'd keep the battery up front. Putting two full sized adults in, and now 20 gal cap tank, watch your gross wt. ! 40 lb max baggage, well maybe solo. Keep an eye on cg location. As fuel burns off cg is moving aft. Pitch gets lite w 2 adults.

WaiexN143NM
Michael

Good call on doing the B conversion. Micheal is right, hold off on going through the effort of putting the battery in the tail until you do your W/B. You might be pleasantly surprised.

Hold off on putting the batteries in the tail until you run all your weight and balance calculations and you are for sure certain you need to do this.

The CG situation for my Viking Waiex was such that I needed to install the batteries in the tail. I can tell you that this is not an easy modification as the control mixer assembly takes up a good portion of the available space in the tail cone.

If you need to move your battery aft I would suggest locating it just behind the baggage compartment. If you need to move the CG further aft then add some ballast at the end of the tailcone between the stabilizers. The farther aft you move the battery the more difficult the job gets because you run up against the control mixer assembly.

If you do move the batteries aft, you might consider using the lightweight cable from Perihelion Design.
http://periheliondesign.com

Aft mounted batteries on my Waiex was one of the most difficult and time consuming aspects of my modification program. I would recommend you think twice before going this route. It can be done but it isn't easy.

Details on my web page. http://www.mykitlog.com/donbowen

My Sonex TD after upgrading to heavier CAMit 3300 up front was just a tad nose heavy. A 2.5 pound lead diver's weight in tail was all that was needed to stay within aerobatic limits, and could remove that when wanting more baggage (traveling with wife). Converted from Odessey PC-680 to EarthEx 900 and saved 10.4 pounds, plus removed the lead weight so saved about 13 pounds.

Battery in tail would require long heavy cables that only add weight and do little for balance. Opposite of conventional tail draggers, Waiex tend toward tail heavy. As others have said, do weight and balance before moving battery to tail.

The new hollow spinner should also be a help, as that little bit of weight saved is right out on the nose.

David A.