C

chris mitchell

Well Known Member
Patron
Not quite sure of the best place for this query but since its going in RV8 I'll post it here.

I have an Infinity stick grip for the P1 stick. I was going to wire it with trim on the coolie hat, PTT on the trigger, flaps on the top, thumb side and start on the top, knuckle side, fuel pump thumb side half way down. This seems like a pretty conventional set up, and should allow me to keep my right hand on the stick just about all the time- which I would see as a big advantage. However, I wondered if anyone using this stick grip, set up in this way, has had problems with inadvertent activation of starter, flaps, or inactivation of fuel pump etc, for example during aerobatics or spin recovery? Do most people have a switch somewhere on the panel to disable the starter once the engine is running?

I know its real "wanna-be fighter-pilot", let's pretend it's an F16/Typhoon/Rafaele/Gripen (depending on where you are), and I guess I have to plead guilty, but I do like the idea of not having to change hands and fumble for a switch......

As ever, I'll be grateful to hear about other folks' experiences.

Chris
 
One way to do it...

I wondered if anyone using this stick grip, set up in this way, has had problems with inadvertent activation of starter, flaps, or inactivation of fuel pump etc, for example during aerobatics or spin recovery? Do most people have a switch somewhere on the panel to disable the starter once the engine is running?
Click to expand...

Chris, we took our initial lead from Bob Nuckolls regards the electric system design on our RV8. I personally did have some reservations about inadvertent actuation of whatever goodies were wired into the stick. Since I'm building an 8, I also wanted to be able to disable all stick buttons and switches on the rear stick if needed.

Here's how we assigned our stick functions:

1. Hat (PB1) – 4 way trim
2. Trigger (PB2) – radio xmit
3. Toggle switch (PB3) – Wing flap control
4. PB4 – Radio cutout
5. PB5 – Starter engage (front seat only)
6. PB6 – no assignment

Starter: We took the Nuckolls route here and used DPDT switches on the mags. One pole of those switches is used as a pass-through for the starter relay engage. The mag switches must be L-ON and R-OFF for the starter to work. Once they're both on, the starter will not engage.

Added notes: The reason for the starter on the stick is to make it easier to hold the stick aft and engage the starter with one hand while you manipulate the throttle/mixture with the other. This must be a point of discussion here on VAF, and since I'm still building I have no actual feedback other than my RV4 had the starter function on the ignition key and so I held the stick between my legs for startup.

Flaps: We're using the toggle switch suggested by Infinity for flap actuation. But, to alleviate ANY issues with a disagreement between flap switch position between front/rear seats, we designed a circuit that makes the front flap switch the "override" switch for the flap system. Without that, and using a standard relay deck, if one flap switch was positioned UP and the other DN, you'd either pop a breaker, or have smoke. Also the flap UP circuit is opened by a limit switch when the flaps are fully retracted. Just hit the switch UP and the rest takes care of itself. Down limit is mechanically done with the motor drive screw.

Radio cutout: I've taken another idea from my T37 days. In the Tweet, the instructor had a button on his stick (only) that could cut out the comm audio, so he could communicate with the student without any interference. I used it ALOT. And I had this in my RV4 and used it alot there too. With someone else in the plane, it sure is nice to be able to shut-out the comm audio and talk when you need to. Of course, you have to use this with discretion. We have this feature on both sticks in the RV8.

And again, we have a switch on the front panel that's "Rear Stick Disable". Switch it off, and ALL rear stick functions are outta-there.

Just our way of doing it, and you'll find lots of very smart thinking here on VAF. Pick and choose what you like, its what makes this so much fun!
 
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chris mitchell said:
Not quite sure of the best place for this query but since its going in RV8 I'll post it here.

I do like the idea of not having to change hands and fumble for a switch......

As ever, I'll be grateful to hear about other folks' experiences.

Chris
Click to expand...

Opinions only, but here is what I did (and would do again):

Trim and PTT as you propose.

Starter as you propose. I do have a "start enable" toggle next to the mag switches.

Instead of flaps on the "thumb side" I have the comm radio flip/flop. I use this all the time, especially in formation. I put the flap switch next to the throttle, where it makes more sense to me.

The left thumb button is the A/P disconnect.

The "reach-around" pinkie button is the transponder ident, which i very rarely use, and I would consider smoke or landing lights or something else.
 
Infinity Stick

Chris,

I have built and flown two RV 8's. The setup I have on the second 8 is identical to what you are planning except for the starter on the stick. A couple of years back there was a lot of discussions on the starter issue with mixed opinions on the pros and cons. After weighing all the issues I elected to keep the starter standard (personal choice). As for the flap switch I agree with the right thumb location and it works well for me, the only firm suggestion I would make would be to make sure the switch is momentary up and down. I learned this the hard way after burning up a flap motor. I also seperated the controls between the fwd and aft sticks with a simple toggle switch on the panel which grounds the switches on each stick depending on position.

Pat Stewart
 
Pat Stewart said:
Chris,

As for the flap switch I agree with the right thumb location and it works well for me, the only firm suggestion I would make would be to make sure the switch is momentary up and down. I learned this the hard way after burning up a flap motor. I also seperated the controls between the fwd and aft sticks with a simple toggle switch on the panel which grounds the switches on each stick depending on position.

Pat Stewart
Click to expand...

Pat - another way to do it is what many of us have - momentary for down (you have to HOLD the switch to drop the flaps) but latching to up (on a go-around, flip it and forget it). The trick to making this work without burning up a motor is to have an "up" limit micro switch that stops the motor when the flaps are full up. Very easy to implement, and very intuitive. Just an alternative.

Paul
 
Infinity Stick grips

When I installed my grips I too used the coolie hat for the two trim functions and the red trigger for the radio.

The flaps are on the silver toggle switch (to the right of the coolie hat) but I have that silver toggle switch as a momentary for both the deployment and retraction of the flaps. I slow count to five for half-flaps deployment and five again to get to full-flaps. I also count a slow five to retract half flaps when doing a go-around rather than have the switch take out all the flaps at once.


Then, the fuel pump is on the blue "pinkie" switch at the bottom of the grip but I don't really like it. Since I still have the original pump toggle switch on the panel it can sometimes be confusing to know if the pump is on or not. Add to that - the co-pilot stick grip is also fitted with a pump switch at the same blue switch so the pump can be turned on at any one of three locations. Not my best decision. I think I'll redo it but I may leave it unassigned.

I use the black thumb switch located at the middle of the grip for my autopilot momentary disconnect, which I really like.

Last, I use the green switch (to the left of the coolie hat) for my smoke system. It is a push on, push off switch. I like that.

I hope this helps.
 
Chris,

For what it's worth, I'm doing just about the same as you are. I will have a switch for both the starter button and flaps on the panel but they will be "Starter Enable Select" and "Flap Enable Select" switches. For example, up for the stick, down for the panel switches.

If you haven't already, take a look at Danny Kings cockpit tour. It may help you make a decision.

http://http://www.vansairforce.net/rvtalk.htm
 
I have a second double momentary switch that flips horizontally not vertically on one side of the coolie hat. One way flip-flops my comm frequency and the other way flip-flops my nav frequency. With the GNS480 it could require 2 seperate button pushes to accomplish a freq change plus I wanted the ability to use HOTAS for high stress times such as landing in IMC. Since I have a push button start on my panel having it on the stick was not reasonable. The other buttons I have are the trigger for PTT, vertically mounted momentary on the other side of the hat for flaps, side thumb button for AP disconnect & CWS, and the pinky button switches between comm1 & comm2.

I have never flown an aircraft with a start button on the stick or yoke. Why is it so important for others to put it on the stick in their RV? I figure that if my engine stops it is a result of something that will not allow it to restart.

My recommendation and I see that others that have responded similarly is that what every switch or push buttons you decide to give a function to have some type of indicator so you are sure they are activated, deployed, on, off, etc without having to think about it.
 
Capflyer said:
I have never flown an aircraft with a start button on the stick or yoke. Why is it so important for others to put it on the stick in their RV? .
Click to expand...

In taildraggers with very high power:weight ratios there is some risk of a prop strike with a bungled (particularly hot) start. Proper technique requires stick fully aft, while simultaneously managing the engine controls.

This is possible with a conventional start button or key switch, but you have to hold the stick with your knees which is awkward.

I know of two local airplanes that were damaged trying to start vapor-locked injected engines. Starting "hot" usually means much wider throttle openings, and occasionally the engine will fire and rev unexpectedly.

For a nosewheel airplane, I wouldn't bother putting the switch on the stick.
 
Thanks for replies

Many thanks for the helpful comments.

I found a thread with a several comments that accidental flap deployment was never a problem. I was going to use a momentary down/latching up with a limit switch. I guess one could disable the flap switch in flight by pulling the breaker if any thing too violent was planned... In fact anything on the stick could be disabled that way. I was certainly planning to have warning lights for starter and fuel pump.

Didn't find any reference to accidental activation of the starter either. There are several solutions to preventing it, on being the Bob Nuckolls idea suggested by Bill Wightman, which I had thought about. Another - which I don't understand so can anyone please educate me is "A diode from the alternator can be installed in the starter circuit that precludes actuation after engine start" - sounds neat and simple but I don't understand how to wire it.
PTT and trim shouldn't be an issue. The rear stick will just be a grip with PTT - no trim, no flaps etc.

Chris
 
flap switch on stick

Has anyone tried connecting flap switches to buttons on stick or do they have to be on a toggle?
jeff
 
Infinity Stick

chris mitchell said:
I have an Infinity stick grip for the P1 stick. I was going to wire it with trim on the coolie hat, PTT on the trigger, flaps on the top, thumb side and start on the top, knuckle side, fuel pump thumb side half way down. This seems like a pretty conventional set up, and should allow me to keep my right hand on the stick just about all the time- which I would see as a big advantage. However, I wondered if anyone using this stick grip, set up in this way, has had problems with inadvertent activation of starter, flaps, or inactivation of fuel pump etc, for example during aerobatics or spin recovery? Do most people have a switch somewhere on the panel to disable the starter once the engine is running?
Click to expand...

Chris

My setup is like yours except I use the thumb-side half-way-down switch for the autopilot disengage. Assuming you have an AP this is a convenient place for the disengage.

After 200+ hours I have not had a problem with inadvertently pressing any of the buttons although I thought a lot about that when I was configuring the stick. In fact I removed the fuel pump button for just this reason but now regret that.

To prevent the starter from engaging I have a simple toggle switch (Radio Shack) on the panel which is engaged for start and then dis-engaged after the engine is running. I located this switch right next to the ignition (mag) switch as a reminder.

I highly recommend the start switch on the stick as it allows you to keep your right hand on the stick and left on the throttle during start.

Also, as mentioned by Paul, I put a micro-switch at the top end of the flap mechanism to act as a circuit break and prevent the motor from burning out. It works fine. As a check I always raise the flaps just before engine start to verify it works correctly.

Chris
 
What type of flap limit micro switches are you guys using - and where did you get them? Any problems with intallation / operation?
 
Micro Switch

pvalovich said:
What type of flap limit micro switches are you guys using - and where did you get them? Any problems with intallation / operation?
Click to expand...

I use a micro switch purchased at Radio Shack for a couple of bucks. It's positioned at the top of actuator arm and held secure with a worm-screw type clamp. You adjust it to close at the point where the moving element of the flap arm stops.

Chris
 
sticknrelays.gif
 
Here's a picture of the schematic I drew up with Design Works Lite. It wasn't easy to get it here. I had to print it, copy it, then upload it to imageworks. How did you get such a nice schematic Kahuna? You must be a Mac person.



The relay is from Radio Shack, part number 275-218. It has a plug in base, available separately. I don't have the part number for that handy. The relay just reverses the current flow to the motor. The full current still goes through the switch.

Here's a picture of my limit switch installation:



There are two of them. One for the AOA system, and one to limit the flaps.
I changed the installation a little from what others have done.
 
Flap Actuation in Throttle Lever??

I'm kind of planning the DJM throttle quadrant and wanted to know if anyone has or if it's an OK idea to put the flap switch in the end of the throttle handle? I'm wondering if putting so many function in the grip gets confusing. Seams like when in or near the pattern, you are already with your hand on the throttle.

Look forward to hearing from those with experience. This forum and all the info is invaluable for us coming along later!
 
But I did stay at a holiday inn express

I don't have a plane of my own (yet), but I do have an F-16 modeled setup for my computer with more buttons and switches than you can shake a stick (no pun intended) at.

IMO, its extremely useful and I've never had a problem with inadvertent button pushing. The buttons are generally in locations you have to move your thumb or fingers to use from thier normal rest positions. Excitement just makes me push the buttons a little harder. :)

I'm not sure what the DJM throttle quadrant is, but from your description I'll take a stab at the question. It'll probably be fine, but remember that your throttle end will rotate and "up" will become "forward" as you move from idle to full power.

I plan on putting any/every function on the stick that'll be of use during busy times that I can. I've even thought of using my computer stick and throttle when the time comes. (and replacing the innards with good quality switches)
 
dbuds2 said:
I'm kind of planning the DJM throttle quadrant and wanted to know if anyone has or if it's an OK idea to put the flap switch in the end of the throttle handle? I'm wondering if putting so many function in the grip gets confusing. Seams like when in or near the pattern, you are already with your hand on the throttle.
Click to expand...

The DJM throttle grip is fairly small, so you'd have to find a mini toggle switch that would fit in there, and work out a way to secure it. I think a mini toggle would be a bit flimsy for that location. For one thing, you'll almost certainly bump into it a few times as you climb in and out. Also, in the operation of the airplane, you might actually bend the switch stem or, worse yet, inadvertently extend or retract the flaps as you're operating the engine controls. Mini toggles don't have much actuation force.

The panel is so close in front of your throttle hand, you might consider putting the flap switch on the left side of the panel someplace. That way, you won't inadvertently bump it or actuate it. It's just not that critical to have everything under your fingers in this airplane, "cool-factor" notwithstanding. :)

Take it from a guy who's used to having 9 switches under his left hand and 7 under his right. :D
 
Getting too complex?

I've enjoyed reading all the comments and have been reassured that my concerns appear not to be justified. I originally started this thread because of the "getting too complex when trying to be cool" aspect. I have heard one report of a VERY highly experienced pilot accidentally running the flaps out, mid-spin. A couple of ex-air force fast jet pilots have pointed out to me that in military jets, the HOTAS technology exists to facilitate time-critical actions when cockpit workload is very high. Much as I love the "cool" aspect and acknowledge the "wannabe fighter pilot" banter, I think that getting too many knobs and switches on stick and throttle is unnecessary for our peaceable sort of flying - and might it begin to impact on flight safety?

To prevent the starter from engaging I will do exactly as Chris Pratt suggests "have a simple toggle switch (Radio Shack) on the panel which is engaged for start and then dis-engaged after the engine is running. I located this switch right next to the ignition (mag) switch as a reminder."

I've spent some time sitting in the (half built) cockpit gripping the stick with both hands and imagining I'm bouncing around in a spin and I don't think my thumb will stray up on top, but if I ever find its a problem then I'll think about disabling the flaps by pulling the breaker as part of my pre-aerobatic check. I'm still thinking about what to do if I discover that I'm accidentally turning off the fuel pump. Have another switch up on the panel? It begins to negate the point of the stick grip.

Just a few thoughts.

Chris
 
Right on the mark... keep it simple

Chris,
I didn't read through the complete email string but the KISS really does play out well in design...

Example of not doing so :) ... I have 7a... spent several hours wireing the stick to turn the autopilot off... bad choice for me... It can be a little "disturbing" to be flying along in a milk jug (solid ifr )... lay something on top of the stick or just hit it with the hand which turns the ap off and see how quickly the RV can react to changed input controls....

Think next time the floor pans are off this will be disconnected.... but it sure did sound cool when building to put that functionality on the stick...

Dou
 
Wise choices, Chris

Chris,

I think you're spot-on with your last post. HOTAS is a requirement for pilots who simply cannot afford to take their eyes off target even momentarily.

But I wanted to remind you of a very neat way to handle the starter safety function: If you use two separate DPDT switches for the mags, then you can simply wire one side of those switches to control starter "enable". With this done, the left mag MUST be ON and the right mag MUST be OFF for the starter to work at all. Once the engine is running, you turn on the right mag and that leaves the starter disabled. No need for a separate switch to disable the starter, and it ensures you have the mag switches properly positioned for start.

This is shown in Bob Nuckoll's book, the Aeroelectric Connection. I highly recommend it.
 
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But I wanted to remind you of a very neat way to handle the starter safety function: If you use two separate DPDT switches for the mags, then you can simply wire one side of those switches to control starter "enable". With this done, the left mag MUST be ON and the right mag MUST be OFF for the starter to work at all. Once the engine is running, you turn on the right mag and that leaves the starter disabled. No need for a separate switch to disable the starter, and it ensures you have the mag switches properly positioned for start.

This is shown in Bob Nuckoll's book, the Aeroelectric Connection. I highly recommend it.
Click to expand...
Nice way of doing it... except for those of us (and maybe Chris ;) ) with dual Impulse mags - standard Superior fit.

Bit of a shame to lose the point/benefits of the second Impulse Mag for a fancy extra stick button :confused:
 
If anyone is still interested this is what I ended up doing with my Infinity stick grips:

1. China Hat - Trim
2. Trigger - PTT
3. Top Inside Thumb - Flaps
4. Middle Thumb - Auto Pilot Control Wheel Steering
5. Inside Pinky - Transponder Ident (or GNS430W Acknowledge if I can figure it out)
6. Top Outside Thumb - Active Radio Flip Flop

This is based on the functions that I use while flying IFR and on approach.

I will not put the starter button on my stick for one simple reason...and its not because I'm worried about pushing it accidently at the top of a loop. Heaven forbid I ever have to try for an emergency restart at 10,000 feet, I do not want to worry about any special circuits or the prop windmilling (generating power) and disabling my starter. If it's on the panel and it cranks the starter every time I push it no matter what else is going on I'm happy.

- Peter
 
infinity stick, revisited

I currently have a simple wooden stick grip with three buttons: a 4-axis trim button--right thumb position, a PTT switch--left thumb position, and a recently installed smoke momentary switch (high index finger position).

I am looking into the functionality of the infinity switch and trying to decide "is it worth it?"

Looking at the switch setups which most of you have recommended, I am not so sure.

Here are the funtions that I would want to have available on the stick, and I am not sure these are possible
--scroll through the Dynon 180 display screens
--cycle through right big knob on Garmin 430 (nav-->wpt-->aux-->nrst)
--cycle through right small knob on Garmin 430 (various pages of each of the above)
--Garmin 430 range in/out.
--PTT
--Smoke momentary switch
--A/P disconnect

I am pretty certain the ability to control the Dynon or Garmin avionics functions are not possible with the infinity stick, else others would be programing those features.

If I had the above abilities, then I would get really greedy and want a TDC switch (like we had in the F-15E--I think it stood for Target Designation Control or something like that) which works like a computer mouse which would be good to use to control the cursor on the Garmin 430 (or better yet, 496).
 
Troy,

The funactionality that you want isn't so much a factor of the Infinity Grip - it is a function (or in this case non-function) of the avionics. I'd like to do what you want with the 430 as well - if someone can find me the pins on the 430 diagram to connect, I'd love to see them! ;)
 
Andy Hill said:
Nice way of doing it... except for those of us (and maybe Chris ;) ) with dual Impulse mags - standard Superior fit.

Bit of a shame to lose the point/benefits of the second Impulse Mag for a fancy extra stick button :confused:
Click to expand...

I need the starter on my stick so that I can hold it back during the start-up sequence. For the interlock, I am using a progressive transfer switch from B&C as a master switch, with the center position as BATT/START and the top position as ALT. In operation, start-up is performed with the Master switch in the BATT/START Position. Once running, it is in the ALT position for the remainder of the flight. All this cost is a wire and relay, but no extra switches.

Vern
 
Holding The Stick Back

vlittle said:
I need the starter on my stick so that I can hold it back during the start-up sequence.
Vern
Click to expand...

You know, I see that quite a few -8 builders go through an awful lot of trouble designing an elaborate stick mounted start button with interlock switch system so that they can "hold the stick back" during start.

I installed my starter key switch in the "stock" Van's suggested location on the right instrument sub-panel in my -8. It's very easy to hold the stick back with my legs while starting. To me, installing a stick mounted starter switch and interlock circuit has absolutely no value what-so-ever in these planes and just adds complexity and weight. Keep it simple!

Skylor
RV-8
Phase 1 Complete
 
As simple as pie..

I put the start switch on the throttle...left hand stays on throttle where it belongs while right hand holds stick. Ergonomic, easy to wire, no interlock switch required just a shroud to protect against accidental start activation.
9pm8hh.jpg
 
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