Worn out Coolie Hat....

[Ironflight]

As I was getting ready to launch for Oshkosh last week, I discovered that my nose down trim wasn't functioning. "Great!" I thought, "I just put new relays in a couple of months ago, and they are the NEW ones that aren't supposed to fail!" Well, I hadn't started the engine yet, so pulled off the headset and listened for the relay and the motor. Sure enough, the relay wasn't working when I pushed the coolie hat - unless I pushed it HARD forward. OK - after 1000 hours, the Infinity Grip switch was becoming intermittent.

I headed north, planning on not trimming the airplane too far from neutral until I got back (this works fine), and while wandering the vendor area, ran across Infinity. I told them of my problem, and was told that I had probably collapsed the membrane switch. OK, so I fly a LOT - I expect some wear. They offered me a replacement, and I enthusiastically accepted - they had a box of spare parts right there. It was interesting that they asked if I waned one or two - I expect I won't need another spare for 1000 hours (I hope!). They charged me $16 for the new one - a reasonable price for a complex switch I guess. Installation will have to wait until I get home in a few days.

File this in the "accelerated life testing department" for those using the Infinity Grip. It's good to know that they do sell replacement parts.

Paul

[Dean Pichon]

I had intermittent trim control and blamed the coolie hat switch on my Infinity stick grip. I replaced the switch only to find the problem persisted. It turned out that I had bad relay. If you still have problems after you replace the switch, you may wish to look at the relays.

Dean Pichon
Bolton, MA
RV-4

[AlexPeterson]

I had my MAC stick switch fail in one of the trim directions a couple months ago, at a bit over 1000 hours. I bought a new switch assy, only to find that the problem was a small piece of junk that had worked its way up into the stick and had gotten under the actual button. This button transmits the finger movement to the microswitch. Oh well, now I have a spare.

[Ironflight]

Originally Posted by Dean Pichon

I had intermittent trim control and blamed the coolie hat switch on my Infinity stick grip. I replaced the switch only to find the problem persisted. It turned out that I had bad relay. If you still have problems after you replace the switch, you may wish to look at the relays.

Dean Pichon
Bolton, MA
RV-4

I've already done the relay dance Dean, and have troubleshot this problem a couple of times, on different airplanes - the reason I brought it up this time is the problem was more unique - you get function if you push hard enough - clearly a problem at the switch. I talked to the relay guys yesterday at KOSH, and they swear that the problems were only with certain years of the REL-1, and the REL-2 is fool proof. (Just wait until they invent a better fool....)

Paul

[RNewman]

These are some of the exact reasons why we came up with Safety-Trim. It limits trim travel to 3 seconds max and has an emergency reverse feature. If you have a failed trim switch in the stick (either failed open or closed) you can always drive the servo back into trim with our reverse switch. Also we a fully electronic solution, so no relays to fail. (Safety-Trim also is a speed controller, with two speed levels that are automatically selected based on the aircraft's airspeed) For all the details check out our web site: www.tcwtech.com and click on the Safety-Trim controller. Also note we have a group buy going on right now through VAF and Stein Air.


Best regards,
Bob Newman
TCW Technologies, LLC.

[Ironflight]

Originally Posted by RNewman

These are some of the exact reasons why we came up with Safety-Trim. It limits trim travel to 3 seconds max and has an emergency reverse feature. If you have a failed trim switch in the stick (either failed open or closed) you can always drive the servo back into trim with our reverse switch. Also we a fully electronic solution, so no relays to fail. (Safety-Trim also is a speed controller, with two speed levels that are automatically selected based on the aircraft's airspeed) For all the details check out our web site: www.tcwtech.com and click on the Safety-Trim controller. Also note we have a group buy going on right now through VAF and Stein Air.
.

Sounds like a nice product, but I'm not sure it does much good for this failure. The airplane gets parked in "landing" trim (because at shutdown, I am too lazy to set it for take-off or cruise until the next preflight). That is very nose up. Now you go to set it nose down, and if the switch doesn't make contact, you're stuck. This was'nt a runaway, it is a non-function. I certainly didn't want to drive it MORE nose up - that would be dangerous.

I have actually not wished I had the speed control in the -8, but in Louise's -6....THAT might be another matter - the gearing seems a bit different, and getting "Mikey" in trim at cruise speed is tedious!

Paul

[RNewman]

Our product actually does resolve this issue. If one of the switches in the coolie hat actually still works, then using the momentary reverse switch on the power switch that provides power to our controller will acutally drive the trim in the opposite direction. Our power switch for the controller is a maintained closure for Normal operation and a momentary closure for reverse action. It is used as follows: For example: if the "up trim" switch in the coolie hat has failed open, then pressing the still good "down trim" button on the coolie hat along with pressing the momentary reverse pwr switch will actually drive the trim motor up. And vice-versa if the down switch fails.

Now if the coolie hat trim switch fails in a shorter manner, then the run away trim prevention feature turns off the trim motor in 3 seconds. Afterwhich time you can drive the trim back to neutral by simply hitting the momentary reverse power switch. After the plane is trimmed to neutral, return the power switch to the off position.

Bob Newman
TCW Technologies, LLC.
www.tcwtech.com