sonex trim systems

[onex28]

Dale could you post a photo(s) of you installation or direct me to web photos, I'd like to see how you designed/mounted the trim control handle. Thanks.

David

[daleandee]

Hi David,

I installed the standard Sonex plans trim system.

http://websites.expercraft.com/daleande ... g_id=55209

http://websites.expercraft.com/daleande ... g_id=66633

I have read where some builder's have increased the size of the trim tab slightly. From my flight testing so far I haven't found a need to do that. But I still have gross weight testing to do.

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
22:30 hours - Phase One
Status - Flying

[onex28]

Thanks Dale, that helps a lot.

[ihab]

Hi there,

[ resurrecting an old thread ]

I have, since I posted my pix, re-done my trim system to be about 75% lighter and quite a bit smaller. It functions the same way, with the panel mounted indicator.

1. Do you have pictures of your new trim system?

2. Has anyone thought of using a mixture knob as a trim control? It would allow quick, large adjustments; it can be rotated for fine adjustments; and the position should be very clear just by looking or feeling. Though I guess one would have to make a mark on the rod somewhere to indicate the neutral "takeoff" position.

Ihab

[n502pd]

Let me dig it out of the to do box, as I have not completely installed it yet. Still working on wings. I will post photo too. The bowden cable from the cockpit to the elevator trim tab is per the plans. the indicator is not designed/built yet,but will be connected by another bowden cable to some sort of top of glare shield indicator, mostly because my round gauge panel is full! Might take a day or to to get the pix and post back.

[n502pd]

I forgot to clarify..my system isnt 'new' per se, but just my clone of the original Sonex method. I didnt intend to mislead. The newer and lighter is in reference to my original clone, which was too large for the afore mentioned full panel.

[ihab]

Let me dig it out of the to do box ....

Thank you! I look forward to seeing it!

I also wonder, idly, whether some arrangement that uses a reduction gear attached to the main shaft, driving a pointer that could either spin on the same bearing as the shaft or on a separate little bearing beside it, would be a good indicator. It would require a lot of mods to the system but it would probably not be too expensive if Sonex added it to their Dial-a-Trim.

Ihab

[Bryan Cotton]

I personally see no benefit to being able to move trim quickly. The only lever type trim systems I have flown were in gliders, and due to the small speed range for normal flight there was limited trim authority. The Pawnee had a spring system run by a window crank. It had an indicator but you could also tell where it was whilst on the ground by where the spring put the stick. You don't really need an indication of trim position while in flight, at least in most GA airplanes. You fly the airplane and trim away pressure.

[ihab]

I personally see no benefit to being able to move trim quickly.

Fair enough, makes sense.

The Pawnee had a spring system run by a window crank.

Sounds pretty good actually....

You don't really need an indication of trim position while in flight, at least in most GA airplanes. You fly the airplane and trim away pressure.

In my own flying (which admittedly has been so far only in the C162 "Flycatcher", with its awful annoying rudder return spring of death from hell, but that's a rant for another thread...), I have a checklist item to to set takeoff trim. In a pinch, if I forget, I can overpower it and just put the nose where it belongs, but it's a bit of a scary feeling....

Ihab

[radfordc]

I personally see no benefit to being able to move trim quickly.

I really liked the lever trim in my old Sonex. When you lowered the flaps there was an immediate strong nose down force. It was nice to be able to trim off most of the pressure with just a quick tug on the lever. Some of the guys with the dial-a-trim just don't bother since it takes so long to trim.