Patrol Throttle Quadrant

[spinningwrench]

After struggling with how to get a two armed throttle quadrant into my Patrol project I decided to design one that would solve my packaging issues. The problem is getting two control linkages out of the quadrant past the 7/8" diameter fuselage tube immediately forward of the quadrant. I elected to bring one motion out from the top of the "throttle" lever and the other a reverse motion out the bottom of the 2nd lever. This allows me to safely get around the 7/8" tube plus allows good clearance to the outside fabric. I also wanted to match the cable throw that is used on my Citabria as it has really nice throttle response so this design gives me a 2.7" throttle cable motion which is identical to the Citabria. Off to the shop.

[JimParker256]

Interesting approach, Spin... Are you going to have a rear seat throttle/mixture control as well? If so, how will they work together? Still struggling with how to do this on my Patrol, which has doors on both sides (seaplane version of the fuselage).

I visited the Legend Cub factory yesterday, and saw how they did theirs. Front quadrant uses the "non-reversing" upper arm for the connections to throttle, mixture, and prop controls. Then the front and rear quadrants are connected by 3/8" threaded rods with forked ends, bolted to the "bottom" (reversing) part of the quadrant (like your mixture control, but all the levers extend down as well as up). The rear quadrant is mounted fairly low, and the rod runs parallel to the bottom of the sea plane door sill, then has an upward bend just beyond door opening to connect up with the lower arm(s) of the front quadrant. They put a small round piece of tubing that is an easy slip-fit for the rod welded to a plate just at the front of the door cut-out, right where the "bend" in the rod almost contacts it in the rear-most position. That allowed them to use the lightweight hollow threaded tubing, but still keeps the rod from just deflecting and bending when forward pressure is applied from the rear quadrant. They say they've been doing them like this for years, and have had zero issues. If I choose to go that route, I'll have to figure out where/how to mount all of that to my QB fuselage... (Here's where I wish I had some welding skills...)

[spinningwrench]

I’ll be doing the pushrod thing as well although I have just finished verifying that the front seat works out and doesn’t interfere with the flap handle. I think it should be fine. I’m doing the quick build as well and already I have welded on various tabs to anchor things. Just finished the engineering change to add the anti-vibration plate in the tail for the elevator tube. My e-mail is spinningwrench@me.com. If you send me an e-mail I’ll fire back some photos of the inside of a Citabria which has been my inspiration although they don’t do the reverse lever concept. I’m putting throttle and carb heat on the sidewall and prop vernier and mixture on the dash.

[Bdflies]

Sorta slow day on the forum, so I figured I’d toss this up as another approach. I did make a throttle quadrant in my Patrol and I’m VERY fond of it! Mine isn’t located behind the tube structure, but is on the 'cabin side'. I have 3 levers (throttle, prop and mixture). I do have rear seat controls for all 3, but I don’t have Jim's left side door. The Patrol is so wide, the quadrant enclosure is a non issue.
The quadrants I used were from Spruce, but I don’t think they still sell the exact ones I used. I think this is the replacement; https://www.aircraftspruce.com/catal...ttlequads3.php
All 3 are direct function with no reversal. I made coupling links (to connect front and rear) from 1/4” OD 4130 tubing. I formed some U's out of .050” 4130 to fit over the control cable clevis' and welded those U's to the links. Pictures attached...
The quadrant cover was pretty close to the original flap lever, but I could operate it - ON THE GROUND. Forces were too high to get 4 notches in flight. So, I made a new flap lever that was longer for more leverage and cleared the quadrant easily.
This system works great and I really like the ability to reduce throttle and Prop, by pulling both at the same time.

Bill

[spinningwrench]

That is a very neat approach. Am I correct in that you ran all the control cables "inside" the fuselage. i.e. they go to the right of the 7/8" diameter vertical tube directly in front of the quadrant. That is the bugger to get around. I have noticed that quadrant in Aircraft Spruce. What limits the range of your motion on the quadrant, it doesn't appear that there are any physical stops?

[Bdflies]

DADE392D-38C0-4067-839C-C5B61AD1B3CF.jpeg Yes, all the control cables are inside the 7/8” vertical. Nothing in the quadrant limits travel. The travel limits occur at the other end. You actually want to hit the forward stops and have about a quarter inch of spring back, to be sure that you’ve gone full stroke of the control. If the lever in the quadrant hits a stop, are you sure that you're really wide open throttle? Just my way of thinking.

Bill

[JimParker256]

Bill, that's exactly what I would do, if I didn't have the seaplane door on the left side. I think I'm either going to have to use reversing levers to join the front/rear quadrant arms (and run them very low, beside the pedal cables) or I'll have to use some form of a flexible cable to join the two. I'm pretty sure that if I use a standard Throttle / Prop / Mixture quadrant, it would be too wide and the most inboard control rod between the quadrants would interfere with either the rudder cables or the flap actuator. I may have to use a single-lever throttle, and keep the mixture, prop, and carb heat on a panel-mounted knob.

I'm only concerned about having the engine controls in the back seat so that I can do my flight reviews in the Patrol. Our local tailwheel instructors are "OK-ish" with no brakes in back, but they want engine control of some kind. I can't blame them for that... I would, too!

[Bdflies]

Jim, you mentioned the Legend Cub. I flew some very enjoyable hours in a Legend, with 2 doors. Those doors folded down and cleared the strut. To do that, the door sill is a good bit higher than the Patrol. Is the left Patrol door a mirror of the right door? The swing-out low doors on the Patrol make for really easy entry and egress, but a rear quadrant will be challenging for sure!

Bill

[JimParker256]

Yes, the left-hand door on the "Seaplane" Patrol is identical to the right-hand. Great for entry/exit, a bit tough for routing controls. Mark G put all the power knobs on the panel (or a sub-panel), and nothing in the back, which would be quite easy. But most CFIs don't like that much...

[Mark Goldberg]

Just to provide a little additional info on throttle quadrants in Patrols - Bob has worked up an installation for a single lever (throttle) quadrant for the front and rear seats. Without the left side door. We thought "standardizing" a throttle installation would be helpful to builders who are happy with just a throttle on the left. And the other controls on the panel. All the Patrols kits coming from the factory are now set up for this installation. Baxter throttle quadrants made some special throttle quadrants for this. Again - this is just the throttle. Mark

[JimParker256]

Mark, do you have pictures / drawings for that? I think I could sell that to the CFI. The main reason they want some form of throttle (I think) is for simulated engine failures, or to be able to initiate a go-around if things get really hairy...

[spinningwrench]

I talked to Dennis Reynolds last night and he wished they had put the throttle quadrant further to the outside so the cables run to the left of the 7/8” vertical tube just in front. As it is the quadrant is too close to the flap lever. BDFlies compensated for inboard mounting by making a new flap handle.

[Bdflies]

I found the original flap handle a bit too short for my liking. The LARGE flaps on the Patrol work really well, but I was never able to pull the 4th notch in flight. To be fair, my quadrant enclosure did pose a hindrance to accessing the handle. The handle I made employs an offset, to clear the quadrant and is as long as I could make it to clear the instrument panel. Pics attached.

Bill

[spinningwrench]

That worked well, quite a bit longer. Actually electric flaps would probably work well here and actually simplify matters.

[Wyo Johnson]

Bill,

That quadrant is a Andair part...same guys that made your fuel selector valve, out of the UK. We just put a similar model in a Lancair and I recognize the machining and layout.

Andy

[jim.mclaughlin924]

I wanted to have the throttle similar to my Citabria, but could not get all the levers on one quadrant. My panel space is crowded as is, so I used push-pull cables. The throttle cable runs between the skin and the frame. The flap handle is standard and clears with no finger pinchers.

[spinningwrench]

Some nice thinking there, elegant throttle. My dual arm quadrant (throttle and carb heat) is going to fit nicely also running between the skin and fuselage, prop and mixture will fit on the dash. I really like vernier control of the prop.

[bergy]

As part of my Patrol building project, I have been trying to maintain my taildragger-flying skills. I have throttle-management problems.

I did my pilot training back in the '60s and finally got my ticket in the spring of '70. I flew a Champ a bit back then too and had no problems. Now almost 50 years later I want to get current again. I went for a ride in a Citrabria about 4 years ago and it went great. I only did one landing that day, it was on asphalt, and I greased it. "No problems", I thought.

Now a couple years later I cannot do a satisfactory approach under anything other than ideal conditions. My problem is that I confuse operation of the aircraft with a farm tractor; I have a lifetime of embedded muscle-memory from thousands of hours on farm tractors and such over the past 70 years (I soloed on a tractor at age 5). All farm tractors I've owned or operated have a throttle which one pulls on to add power. I have no problem keeping the difference in mind when flying at altitude, but on final approach there is not really time to think, any more than a guy riding a bicycle tells himself "Oh... I am tipping over. I must turn the handlebars to the right".

So the obvious solution is Practice/Practice/Practice. But I don't what to spend my Social Security $$$ on aircraft rental fees. So this is what I did today...

I fashioned a tractor-throttle extension for the left side of one of my tractor's instrument panel. It is located quite a bit forward of where my Patrol throttle-quadrant will be located, but at least it will allow me to push/pull the throttle in the correct direction. It will help me when I drive the tractor too. This past summer after going for a one-hour jaunt in a Citabria, then coming home to hop
on tractor found myself killing the power to the tractor engine when I starting bogging down in a soft spot.

TractorThrottleMod-2014.jpg