wera710

wera710

Well Known Member
I have a nearly new condition grip from an F4 Phantom (think OTTO B8 and you have the general idea) for the front stick and a NOS grip from a P-80 fighter for the rear seat, since I did not need a load of functions back there. The front grip is your normal military type with a cooly hat and four buttons for various functions, plus a two position trigger. The P-80 grip has a cooly hat, one PPT SW and the same two position trigger.

My questions are based on what I've read about Infinity installations. Everyone is talking about individual ground wires for each button. But in the grips I have the PPT and other 3 switches are simple Momentary On, Normally Open types with only one wire going in, one wire out (hot). No grounds at all. The Cooly hats have a common plus four wires for up-down-left-right. The triggers have one hot common plus two outgoing hot leads.

I want to hook up the cooly hat for elevator trim. Currently I have a Ray Allan RS2 for a trim switch. The military type grip has one wire for up, one for down, and a common (we are ignoring the two aileron wires for now).

Question 1. Is there any reason for grounds inside the grip as the wires going into the grip are all hots? I am assuming everything can be grounded down stream.

Question 2. What will I need to wire the cooly hat trim switch to the Ray Allen Co. system? I am told I may or may not need a relay. Any ideas which RAC relay I would need? Anyone ever do this and have a wiring diagram?

Question 3. I would like to wire the fuel pump to one of the red momentary button switches. Any recommendations on a relay that will allow the Momentary On, Normally Open switch to trigger the pump via one push = on, second push = off? I'd like to keep the existing right side panel switch as a pump master switch and just set the stick up to engage the pump.

Question 4. The Trigger. I would like it to operate a camera. It has a common wire and two hot wires. When the trigger is pressed half way back, one outgoing hot get power. All the way back and both out going wires are hot. Anyone have experience with converting motorcycle cams or av-cams to this type of trigger system? Idealy I would like the first step for momentary on (ex: press on and cam runs till I let off)...but I am wondering what would be necessary to use the second setting to turn the cam on full until clicked again- looking for click on...click off. This possible?

Any help would be greatly appreciated. Thanks!

Scott
 
Ray Allen has many sketches of trim wiring on their website. As to these switches and grounds, they are "switch legs". Some may end up going to ground and some not. I would not call them ground wires in the normal use of the word.

L.Adamson ---RV6A
 
You are going to need to build some sort of interface relay box to do some of things you have in mind.

I am ex-Air Force and have an F-4 stick grip as well and had the same thoughts. But, I decided trying to use it was impracticle. It is big and heavy for such a small stick and the base diameter is just shy of 1.75" which would not look acceptable to me sitting on the skinny stick. You are also need to build a custom plug to mate to the stick pins. Infinity was the choice for me.

Good luck.
 
The B8 Stick Grip

If you don?t mind wrapping your hand around the positive post of the battery during all your flying, I guess that?s ok.
I believe using the stick buttons as grounding switches activating whatever circuit they are wired to more practical and safer. I have seen many frayed wires and burned spots in surplus B8 stick grips. I put the power to one side of the activating relay coil and use the stick switch to ground the other side. When the wires in the stick break or fray (which the do)?..no harm done when you press them. Because trim relays, radio active/standby circuits and many other devices are controlled by grounding, wiring become less complex (in my opinion). Of course you still have to have power sitting on one side of the circuit which is being activated.
The wiring philosophy I use is to keep the hot wires as short as possible and let the ground side run to all the activating switches. The less hot wires I have running around (especially in moving components) the better.

Good luck with your project
 
Frank, that seems like a pretty wise method. Make 'em all grounds. Works for me. Had not got that far into the "how too" yet. Was still in the "can it be done" phase.

Being self employed I've not had a lot of time to surf for info but I guess I am going to have to screw off at work a bit to go surf RAC's site. I can always fire myself later. lol.

Thanks guys.
 
A Year Later...

Here it is a year later and I finally got around to installing the otto stock grip from the F-4. Gotta admit, I am one of those guys who would rather fly than tinker, so it took me a while. Anyway...On the sizing, I had a local machinist make a reducer to size the grip to the stick and surprisingly, it looks pretty good. Not much different than the infinity grip.

Set up will be:

Top Red momentary SW: Radio Transmit.
Coolie hat: Elevator Trim
Middle Push-On, Push-Off: Unassigned but eventually Smoke.
Trigger: Camera
Pinky SW: Fuel Pump.

Need some advice on the relay options.

I need a relay for the Facet Fuel pump (the 6 psi max model in Van's catalog). I am keeping the original pump switch on the SW panel to act as a master and want to use a relay to interupt the ground side through the stick pinky SW. Looking at Aircraft Spruce, I've no clue which to order or if something else would be more appropriate. Draw is 1 amp. Anyone with an electrical background got a link to an appropriate product?

The second relay would be for the elevator Trim. Using the original cooly hat in conjunction with the Ray Vin electric trim. Guessing I am going to need a relay and here I am totally lost. Last time I did a search I think there were half a dozen options. The SW has three wires, up, down and common. Any links to the most appropriate relay would be most helpful.

Sorry to be a bother. Figured some of you guys have researched the heck out of this sort of thing so rather than spend a month boning up on electronics, I'd go right to the experts.

Thanks ahead of time.
 
"Standard" relay scheme for control of a trim motor through grounding two-way switches on either stick. This drawing is mine but you'll find similar (and perhaps more clear) elsewhere:



Good source for relays, toggle switches, the good glue-lined heat shrink and some other basic electrical supplies here:

http://www.delcity.net/store/Relay-!-with-mounting-bracket/p_73576.a_1

For the fuel pump I'd just chase down a latching push-on, push-off switch to replace the momentary button currently in the stick grip. From there all you would need is a single relay, same type as above. The stick switch grounds a circuit through 85/86, pump power runs through 87/30.
 
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Just to be clear, Dan: the "73982 - Change Over Relay w/resistor, 15/20A at 24V DC (1 MIN)" is the best choice of relays because the snubbing resistor is built in. With a regular relay, external diodes (or resistors) would be required to protect the switch from the coil transients.

Vern
 
Sweet! Thanks guys. I've already replaced the momentary SW with an OTTO type from Spruce that latches on once pushed until pushed again to disenage.

My next concern then after the fuel pump will be how to wire the relay into the Ray Allan trim system. No happy with the rocker SW. anyone have a diagram for that one?
 
Fair point Vern. I didn't show protection in the drawing.

Curiosity question for the EE's: The base relay without resistor or diode has a coil current around 150mA maximum and the coil itself is small. I wouldn't expect much of an arc when you open the switch contacts, but I have no idea how to judge. How does a designer quantify the actual need for switch protection?

Scott, the posted diagram shows a hat switch (SPDT) on each stick, as I assumed you're still planning to use the P80 grip in the back. With one hat switch you still use two relays wired as shown.

The Ray Allen rocker is probably a DPDT with internal connections like the external connections on a flap switch.

For a rocker switch in parallel with one hat switch the simple approach is to get a (on)-off-(on) rocker and wire it in parallel with the hat switch, just like the diagram.

This is the one I used in the back seat of my -8:
http://www.delcity.net/cartviewitem?item=7500007&search=y
 
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Scott, any of the Vertical Power systems make this type of wiring really easy. The trim switch wires each go to an input pin (whcih runs the trim when grounded). The camera, pump, etc each also go to an input pin, which is then configured to turn on a device when that pin is grounded.
 
Vern - NOT the 73982 --

vlittle said:
Just to be clear, Dan: the "73982 - Change Over Relay w/resistor, 15/20A at 24V DC (1 MIN)" is the best choice of relays because the snubbing resistor is built in. With a regular relay, external diodes (or resistors) would be required to protect the switch from the coil transients.

Vern
Click to expand...

-- it's got a 24 volt coil operating voltage.

http://www.delcity.net/images/linedrawings/73982.pdf

Unless you have installed a 24 volt system in your RV...:)
 
DOH

Ok, now I am confused. lol...The fuel pump draws 1 amp. Its a 12V system. But if I am reading you right, I should get the 24V relay with resister that is rated 15/20A.

As you can tell, my experience with relays is zero (unless you count the one pound beast in my 48 Willys Jeep!). I'd have thought something in the 1 to 5 amp range for 12V. Just want to make sure the 73982 will work at at 12V and 1 amp.

Dan, thanks for the clarification. Currently I have the Ray Allen rocker mounted up front, on a panel above the throttle quad, along with a flap toggle. I plan on eliminating it completely and just using the hat SW on the stick. Have no immediate plans on enabling the hat SW in the back but eventually will do it when I figure out where to squeeze in a cut-out SW so the passenger can not accidentally (or on purpose - I have evil flying buddies) screw with the trim.
 
No- I said...

wera710 said:
Ok, now I am confused. lol...The fuel pump draws 1 amp. Its a 12V system. But if I am reading you right, I should get the 24V relay with resister that is rated 15/20A.

As you can tell, my experience with relays is zero (unless you count the one pound beast in my 48 Willys Jeep!). I'd have thought something in the 1 to 5 amp range for 12V. Just want to make sure the 73982 will work at at 12V and 1 amp.

.....
Click to expand...

...the 73982 is the WRONG part - it will not work in a 12 volt system.

Vern misspoke to put it in PC terms...:)

-----------------------

This one will work - the 74982

http://www.delcity.net/images/linedrawings/74982.pdf

Or this one, with a mounting bracket and 1/4 inch fast-on terminals - the 73994

http://www.delcity.net/images/linedrawings/73994.pdf
 
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My schematic for the pitch and roll trim controls:

G2%20Pitch%26Roll%20Trim%20Circuit.jpg
 
az_gila said:
...the 73982 is the WRONG part - it will not work in a 12 volt system.

Vern misspoke to put it in PC terms...:)

-----------------------

This one will work - the 74982

http://www.delcity.net/images/linedrawings/74982.pdf

Or this one, with a mounting bracket and 1/4 inch fast-on terminals - the 73994

http://www.delcity.net/images/linedrawings/73994.pdf
Click to expand...

What? You guys aren't using 24 volts? Actually neither am I. Here's a part number of a relay that I am using in my HR-II Project: Digikey 255-2161-ND.

Vern
 
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