Show me your electric trim

[sub3]

would like to see some pictures of electric trim switches and indicators? I'd like to do a combo trim switch with a center push to talk but can't quite locate the right style..

something like this
https://www.otto-controls.com/-/media/products/literature/Trim-Switch-Overview.ashx

[stewartb]

My trim switch is on the top of a Tosten grip. It’s a 4-way switch with a blocking plate to limit it to nose up/nose down. The PTT is in the trigger. My trim indicator is on the G3X.

[wireweinie]

I'd like to do a combo trim switch with a center push to talk but can't quite locate the right style.

That's a bad idea. Keep trim controls on one switch and radio/audio functions on another. Don't mix functions on a single switch.

Web

[stewartb]

Call Kevin at Tosten and talk to him about what you want. He can configure grips in more ways than shown on his web page. Mine's a CS-6 and it's absolutely perfect in my Cub. WAY better than a rocker switch on the end of a tube that I started with.

[frequent_flyer]

Some people love the front seat grip on the FX-3 Carbon Cub. It has trim, A/P disconnect, and PTT switches. I have slim hands with a 9.5 inch span and I find the trim switch very awkward to use. When holding significant stick force I use my left hand to operate the trim switch as my right thumb doesn't reach it without changing my grip.

I suggest getting "hands on" time with the grip and switch combination before purchase. One size doesn't fit all.

[wireweinie]

Sticks and grips are like (women, partners, significant others, or whatever the word of the day is), they have to make you happy when you have your hands on them.

Seriously though, if you want a grip or a specific stick angle, play around with what you think you want. You may stick with that choice or you may end up changing your mind a couple of times. But verify before you spend money.

Web

[sub3]

I hadn't thought of a grip, I will look into it. My last cub was a regular stick with the PTT on top, I liked it that way, nice and simple, the problem comes with introducing electric trim and keeping with the KISS method.

[wireweinie]

The typical trim switch will be a 'china hat' style. Seems to work well in most installations but it was designed for a four way type of movement, i.e. left/right and fore/aft. If you only need the l/r or f/a, you can use a rocker or toggle type switch.

Decide what you need to control at the grip and then look around for a grip type that works for you and has mounting spots for switches in the correct locations. There are a bunch of aircraft out there flying with a trigger for PTT and a single china hat for trim. Simple setup and defined uses for each switch.

Web

[stewartb]

If you go with Tosten, the $20 add for Soft Touch is well worth it. Not cushioned at all, but warmer and more pleasant feeling than hard plastic. Kevin can make the 4-way hat switch work in single axis. No extra charge when I ordered mine. I could have added the AP disconnect, too, but left that in the panel.

Depending on your trim you may like the TCW Safety Trim. It provides runaway trim protection and lets you run the trim in two speeds. I really like electric trim in my Cub. More than I expected.

[sub3]

Good tip on the TCW safety trim, thank you. I'm looking forward to electric trim vs. a window crank.

[Marty57]

The typical trim switch will be a 'china hat' style. Seems to work well in most installations but it was designed for a four way type of movement, i.e. left/right and fore/aft. If you only need the l/r or f/a, you can use a rocker or toggle type switch.

Decide what you need to control at the grip and then look around for a grip type that works for you and has mounting spots for switches in the correct locations. There are a bunch of aircraft out there flying with a trigger for PTT and a single china hat for trim. Simple setup and defined uses for each switch.

Web

So, do you put the switch for the trim on one stick or both? If two, how's that work?
Marty57

[Gordon Misch]

Wire parallel.

[wireweinie]

In a nutshell, each china hat operates relays to control trim motors. If you use separate breakers for power supply to each china hat, the pilot can open the breaker to the back seat to stop that guy from interfering with the pilots inputs.

Web

[Mr. Ed]

I made a clay mold that fit my hand then reproduced that shape in hand carved maple burl. I took the grips to Pioneer Control Grips in Redmond, OR and they fabricated a switch plate and installed the switches, trim, push to talk and autopilot disconnect. They did a great job. They make their own grips out of wood or carbon fiber and can customize the buttons and layout to suit your needs. My grip fits on a control stick that is angled forward at the top so it’s more comfortable…to me.

[Marty57]

In a nutshell, each china hat operates relays to control trim motors. If you use separate breakers for power supply to each china hat, the pilot can open the breaker to the back seat to stop that guy from interfering with the pilots inputs.

Web

That sounds like a great solution; simple. Now ..... I just have to remember that tip when I wire everything up. I don't suppose you a solution to that problem, do you Web? If I could just find that notebook ......

Marty57

[wireweinie]

I'm always hanging around. Just give me a shout. I can draw it up or wire it for you.

Web

[frequent_flyer]

So, do you put the switch for the trim on one stick or both? If two, how's that work?

CubCrafters uses a trim priority switch and relay to decide who wins if front and back seat trim commands are in conflict. Not sure if the complexity and added failure modes are worth it but it has not given me any problems yet.

If you have an autopilot you also need to consider how it will behave in a runaway trim situation. An AP disconnnect with a large out of trim condition can be "interesting".

[Bill Rusk]

This is the simple version that works for me.


Put your PTT switch on the throttle ball.

Just one idea.

Bill

[hotrod180]

I had the opposite thought...
PTT on stick, trim switch near the throttle.

[Farmboy]

I too have enjoyed a Tosten on two different cubs, as well as friends. Seem to work quite well for me.

If you really want to explore grips, hats, switches and buttons, go search the vans airforce forum. Those guys have played with everything.



Sent from my iPhone using SuperCub.Org

[Cub Builder]

Purchased this stick grip from Chief Aircraft a number of years ago.
Have the same in the back seat with a relay deck so trim works from either seat.

[wireweinie]

Another scratchy drawing. This is a quick and dirty way of wiring two sticks to control a single axis trim system. Hold on to your hat for the explanation!

There are two spdt relays. Notice that both relays hold the common contact (c) to ground, through the normally closed contact (n/c). The upper relay is connected to the motor through the red wire and the lower relay is connected to the motor through the black wire. If either trim switch is pushed to the CW position, power is applied to the upper relay, moving the (c) contact from the (n/c) to the (n/o) contact. When this happens, trim motor power, from a breaker, is applied to the motor through the red wire. And since the lower relay still has the black motor wire tied to ground, the trim motor will turn in a clockwise direction.

If either switch is moved to the CCW position, the same, but opposite, function will take place. The upper relay will keep the red motor wire tied to ground but the lower relay will apply power to the black lead. This will cause the motor to move in a CCW direction.

Each relay coil is tied to ground through a 'bump switch'. This is the travel limit switch. They need to be mounted where the surface being moved (like the horizontal stab) will hit the switch when it is at maximum travel, one in each direction. When the switch is contacted it will open the ground path for the relay coil and the relay contacts will return to the (c) to ground through the (n/c) contact. This prevents continued travel in that direction but still allows for travel in the opposite direction.

A separate breaker needs to feed power to each trim switch. If the pilot needs to prevent the opposite stick from operating the trim, simply pop the breaker for that switch.

If there is a runaway, either, through malfunction or someone frozen on the other trim switch, the pilot can simply push his trim switch in the opposite direction. This will energize the relay previously providing ground, thereby removing the ground path for the trim motor. This action prevents the motor from moving in either direction, and allows the pilot time to pop circuit breakers without the danger of electrical or mechanical damage.

Fire at will!

Web

[Marty57]

Another scratchy drawing. This is a quick and dirty way of wiring two sticks to control a single axis trim system. Hold on to your hat for the explanation!

There are two spdt relays.....

Web

I think I have it figured out .... I had tested mine with a single switch and a couple of diodes but this seems to eliminate the need for the diodes and allows for two switches. Can you specify a specific spdt relay; there seems to be a lot of 12V relay options.

I set up my limit switches to contact the trim yoke. I used the trim motor and yoke from Javron. Lots of ways to locate the limit switches.
Marty57

[wireweinie]

Most any relay will work as long as it's sealed, the coil is the right voltage (12 volts here), and the contacts handle the amps that the motor draws in the worst case scenario.

This is a pic of the style I really like, but they are expensive. There are at least three brands of similar relays so make sure the specific model meets your criteria for your install.

Web

[wireweinie]

Even fog light relays will work for this.

Web

[Marty57]

Even fog light relays will work for this.

Web

The range in price is from $5 -$200; how do we decide on what is a good relay?
Marty57

[wireweinie]

The range in price is from $5 -$200; how do we decide on what is a good relay?
Marty57

How hard will it be to replace the relay if it fails?

Web