SonexBuilders.net

DCASonex wrote:Clockwise viewed from the rear is same as CAMit and Jabiru engines but I think is opposite that of AeroVee engines.

David A.

Correct you are. The VW & Corvair both turn counter clockwise viewed from the cockpit and require left rudder for take-off.

Between my helicopter time and all my Waiex time I'm going to be all screwed up if I ever get behind a lycasaurus again.

Bryan Cotton wrote:Between my helicopter time and all my Waiex time I'm going to be all screwed up if I ever get behind a lycasaurus again.

Doubtful you'll have a problem. I've had folks ask me how I deal with an engine that turns the "wrong way." My reply is that I look out the window and tell the plane what I want it to do ...

Dale
3.0 Corvair/Tailwheel

daleandee wrote:

Bryan Cotton wrote:Between my helicopter time and all my Waiex time I'm going to be all screwed up if I ever get behind a lycasaurus again.

Doubtful you'll have a problem. I've had folks ask me how I deal with an engine that turns the "wrong way." My reply is that I look out the window and tell the plane what I want it to do ...

Dale
3.0 Corvair/Tailwheel

Agreed! I think it must be very close to instinktive, to keep the aircraft straight on TO/CO. Most pilots will correct any tendency to yaw/turn with the appropriate boot/input.

Murray Parr wrote:

Skippydiesel wrote:Hi Murray.
In comparison - my Sonex requires corrective right boot only during TO/CO.

How much rudder do you need, anything like the 3/4 of the way to the floor like mine needs?

Made it to the New Year :)

Have another hour or so since I last wrote - Murray: it's hard for me to quantify the amount of corrective rudder on TO/CO - subjectively it doesn't feel like very much ie what I would expect. I think, on my role/initial acceleration, I start with quite a bit boot, progressively lessens with speed/rudder authority. Still having some corrective boot throughout climb. Sorry to not be more objective. Wet weather inhibiting flying opps - will keep trying to observe my TO/CO actions.

I am pulling back (for the moment) from installing Barry Controls PN 22001-14 (stiffer mounts) and going for an interim modification: letter to Sonex-

"I may have a KISS solution, that does not involve stiffer mounts (at this time) with the added bonus of being both relatively quick & low cost, to implement.

Given that my particular installation Rotax 912 ULS + Airmaster CS and now 70 hrs engine time, there seems to be an issue with lateral movement, particularly in the rear/aft mounts.

My agriculture interpretation of how the Hutchinson Barry Controls 22001-13 mounts work (please feel free to correct me):

(For the purpose of discussion, I am separating & exaggerating, the function of the upper t & the lower mount. Realise that when correctly installed they work together)

• The upper part of the mount is responsible for vibration control.
• The lower part (donut) for movement control.

If I contain the lower mount (donut), in a “cupped washer” ie flat washer with vertical sides of suitable dimension. The donut movement would be better restricted ie resist the lateral movement of the mount and thus the rotational movement of the engine?

The Barry 22000 Snubbing Washer PN 9810145-01804 is 1.56” (39.624mm) x .391”(9.9314mm) x 0.90” (2.286 mm) - I can source the metric equivalent locally (40 x 10 x 2.6mm). To this I can weld a ring 8mm high (donut is .485” (12.319mm) high/thick), thus making a Cupped Snubbing Washer.

Alternatively:

The pre installation dimensions of the donut, is 1.31” (33.274mm) diagonally – I can make a Cupped Snubbing Washer, using a smaller 35 mm OD washer. This would, on installation/tightening up, restrict the sideways spread of the donut, resulting in some pre load/compression, that may further reduce the movement of the lower mount.

From my perspective the beauty of this is, it utilises the exiting mounts, just changes the way the lower donut is contained, can be installed without lifting/removing the engine and is low cost, it does not require a step into the engine mounting unknown."

Sonex refuse to comment.

Can you blame them? They have not tested your solution. That is the beauty of experimental aviation, you can experiment all you want! I say give it a try and see.

Bryan Cotton wrote:Can you blame them? They have not tested your solution. That is the beauty of experimental aviation, you can experiment all you want! I say give it a try and see.

Yes I can & I do - I am no looking for them to tell me what to do, just give me the benefit of their knowledge/experince.

It's up to me (the builder) to decide what to do/system/mods to implement.

Moving forward!

Cupped Snub Washers have been installed and the engine run - everything looks good so living in hope. It would be great if I could send photos but never had any luck posting on this Forum - if you want photos, I can email them to you.

If weather Gods are with me, I will fly tomorrow.

I expect I will need to do quite a few hours with engine stop / starts, before I will know for sure if this very simple, low cost, nil risk modification(KISS) actually works to reduce engine lateral movement.

Up Date:

2 X 1.5 hr flights, including about 6 touch & goes, same day (made the most of a break in the wet weather).

Bottom donuts all stayed in place, thanks to the Cupped Snub Washers.

Checked for excessive engine movement - Unfortunatly still too much.

Will purchase the next level stiffness of Barry Mounts PN 22001 -14.

Thinking I might start by replacing the -13 bottom donuts with the - 14 ie retaining the upper part of each - 13 mount, to preserve most of the original Sonex supplied installation.

If that doesn't have the desired effect, will replace all of the Sonex -13 Barry Mounts with - 14's

FYI: The Hutchinson/Barry Controls 22001 series only goes to - 15