SonexBuilders.net

TaxMaverick wrote:Sonex says their plane will do 170 MPH at 8,000 feet with a Jabiru 3300. Rotax cruisers seem to top out at about 130 or 140 MPH (S-19, RV-12 and CH 650). Of course these planes are all bigger than the Sonex and the speed difference is not huge.

This European tandem with retractable landing gear claims to cruise at 250 KPH (150 MPH) with a 912 ULS. http://www.shark.aero/index.php?lang=en. In case you are interested in this plane, they are asking USD 180,000 in the U.S. Rotax offers different gear ratios. So, this tandem may be using a gear box optimized for high speed.

The honesty of Sonex I have seen called into question on the internet almost as often as Jan. I won't believe their 170 MPH number unless I see it.

I only read in a couple places that direct-drive engines are better for cruising. It seems logical to me.

Please excuse my ignorance if I am saying something completely wrong.

I'm the guy with with the first Viking on a Searey LSX. I also had an RV-12 kit that I intended to complete with a Viking engine.

I worked with Jan Eggenfellner for about 9 months and even brought my kit to his shop and allowed him to design and install the Viking/Honda mounts and wiring harness on my plane. I had great expectations for the success of the engine and made several efforts to get Jan to work more closely with the Searey factory engineers to enhance the process. He did come to the Searey factory while my plane was being completed there and discussed issues with Searey personnel, but ultimately he did things his way.

From the first flight it was obvious the engine made the plane SERIOUSLY aft C.G., to the point that I had to fly with 30 lbs. ballast in the nose and full nose down trim to fly straight and level. When I landed on the water it was necessary to immediately push the stick forward to keep the plane from bouncing back into the air. The same was true for grass strip landings. The engine with necessary accessories weighs 25 to 30 pounds more than a Rotax 914. That weight is primarily aft C.G. on a Searey. Jan Eggenfellner wanted me to raise the engine, move it forward on the root tube 3 inches and use a prop spacer. The Searey factory advised against these changes, saying they would not satisfactorily solve the problem.

A thrust test during the build process, at the Searey factory, and before installation of the wings, windshield, canopies and everything else that obstructs air flow to the prop, showed 475 lbs. of thrust; however after the plane was completed and flying, several different degrees of prop pitch were tested and the best thrust developed under nearly identical conditions (at the factory) produced only 425 lbs. thrust. An 80 hp Rotax, on a Searey, was tested immediately after my test an developed 435 lbs. thrust.

I never flew with more than myself (174lbs.) and 12 gallons of gas in the plane and never achieved satisfactory climb out performance. Average was around 500 fpm. The Searey is heavy (998 lbs. empty) and has lots of drag.

I also had several occasions when the engine "burped" and the last one when it ran very rough for long enough that I had to engage the back-up ECU to stay in the air. Three times Eggenfellner flew over and adjusted the ECU by connecting his laptop computer. Each time he said it was not a big deal and not to worry about it. Well, I did worry about it and the last time he adjusted the ECU was the last time I flew the plane with the Viking Engine.

Eggenfellner had a long list of changes he wanted to make to my newly completed plane to continue his R & D process, but I'm not a test pilot and it was apparent that the R & D was going to be an extended process and turn my show plane into something I would no longer be proud to show.

With all that in mind I decided it was in my best interests to return the engine and install a Rotax 914. Eggenfellner did an about-face, from friend to enemy; refused to refund my money (contradicting his advertising and our agreement) and even attempted to obstruct my efforts to sell the engine, by telling a potential buyer it needed $2000 in upgrades and they would be better of to buy an new one. I explained my reasons to Jan and suggested that not living up to his promises was bad for business, but he became irate and said I didn't deserve a refund. Luckily for me, the buyer bought it for $8000, in hopes that he could get it upgraded. My loss was over $4000 and I had to sell my 90% completed RV-12 kit to get $$$ for the Rotax 914.

That pretty much sums up my experience with Viking Aircraft.

I'm completing the installation of the Rotax 914 and look forward to flying my Searey with the tried and true engine for which it was designed.

The Onex has a straight firewall. We designed a mount for the Viking. The Viking will fit 100% inside the cowl, not partially outside like the VW.
I believe there will be 90% viking engines in the Onex. The airplane is rated for 216 mph Vne and is built like a tank. It needs power.


Jan

SouthernMage wrote:I agree it will fit inside the cowl , but how does it look? Does it flow with the aircraft lines or does it look like an afterthought?
The picture of the Sonex cowl around the Viking eng dosnt look good and i doubt the smaller Onex could look any better with a fat square nose.
Dont get me wrong I like the engine. You just cant put a square peg in a round hole .

Joe