TruTrak Sorcerer trim up trim down in alt hold

Have the above Sorcerer installed on my RV-10 and when I hit Alt Hold when trimmed at altitude I get trim up and trim down commands, even the slight bump to correct trim is too much. Have ignored up/down commands and up/down commands still come. Have had some pretty drastic nose up and nose down pitches with Alt Hold ingaged as well.

If I am at altitude and trimed and engage auto pilot without alt hold the autopilot will hold altitude or have a slow altitude loss or less than 50 fpm, set a climb for 100 fpm up and will pretty much hold altitude or very slow climb. Set it for 200 fpm down give me a 500 fpm rate down.

Another issue is with the AI in cruise which shows a 20 degree turn with right wing low and does not seem to move with the plane. The AI will work fine the next flight. The vaccumm gauge reads low green but at last inspection by Walt Aronow tested the vaccuum pump to be working ok at the engine, so unless leak in line likely AI needs work. Not sure if AI connects to TruTrak in any way or not or if TruTrak has it's own gyro.

Any help on either would be appreciated. May be simple setting on TruTrak for at least 1st problem. I know some have put a switch to slow trim at cruise and would think this might be a solution if did not hold altitude as well as it does with alt hold off and auto pilot engaged.

Thanks

Gerald George
RV-10

Static leak

Greg,

Had a similar problem with the same system that turned out to be a static system leak. Fixing that solved the Alt Hold issue. I suggest you sort that out first before adjusting settings or trim speed.

The trim speed does not affect the altitude hold of the Sorcerer. It will, if you over trim, have a harder time holding altitude. Make sure you torque is at 100% on the pitch servo (push and hold ALT button to get into pitch settings). You can also change the activity and micro activity and static lag, but as was already mentioned, I would recommend you check for a static leak before doing these other things. Go to an avionics shop and asking them to hook up their static system tester and they will let you know if you have a static leak and how bad it is. You don't have to get them to certify it, just pay an hourly rate to have them check the amount of a leak you have. You may be able to find the leak without that too. You can open and close your fresh air vents to see if the altimeter changes at all, which would indicate a significant leak in the cabin area.

The attitude indicator has no bearing on the Sorcerer, so that is an independent problem.

One other things to check, since you mention drastic nose up/down pitch changes in altitude hold mode, is to make sure your pitot and static lines are connected to the proper ports on the autopilot. If you have the pitot line plumbed to the static port of the AP, it will cause a roller coaster effect in altitude hold.

static leak

Had the altimeter, encoder and static check done in October per Exp Aircraft in order to fly IFR. No problem found and Trutrak was acting up prior to that. Had worked rock solid in past so doubt pitot and static hooked up backward. Perhap static leak or input to Trutak came loose. Any other ideas or just recheck for static leaks?

Thanks for the ideas.

Gerald George
RV-10

Try pulling the sorcerer out of the tray and looking at the back of the tray and the back of the unit to see if the mating connectors for Pitot and Static look like they should be sealing well. If so, try reseating the programmer and tighten down well and try again.

Jesse said:

Try pulling the sorcerer out of the tray and looking at the back of the tray and the back of the unit to see if the mating connectors for Pitot and Static look like they should be sealing well. If so, try reseating the programmer and tighten down well and try again.

Click to expand...

And while doing so, use a free hand to put pressure on the Sorcerer as you tighten the jackscrew.