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Make My Own Throttle Quadrant?

David Paule

Well Known Member
Yeah, I'm thinking that would be fun. Why not?

I'm looking for two dimensions and a name -

1. The name and model of the unit you're measuring.

2. From the pivot to the handle for all three levers.

3. From the pivot to the cable attachment point for all three levers.

Thanks very much!

Dave
 
I machined my own quadrant. Not hard to do if you have a lathe and mill. Somewhere I have a Solidworks model of the whole thing, and have a separate Solidworks sketch to determine hole placement based on cable travel. If you are able to work with SW I can post the files if I can find them.

The throttle has trim, flap, and smoke buttons, which are out at the time of the pic. I milled a groove in the arm to run the wires, which connect to an Arduino. There is a UHMW top plate to guide the levers.

On the knobs I used candy powder coat applied with an airbrush and heat gun.

RvQrRtoWqhVwPeeEQwkkG4hPhH8UaLnJWhYiqw5ZFPEzgS-7ZGcq4KBSqJES4su6Ck-Nt50NzrX_ISmrXsFOxb9niBETPgMg4LmfIxtoTlnMZrnxZwBvkHhX_uBOF6TxI4cYNJzcmPWDpR-HyOAI-AeAdLhtchQl3QYmdmlIbWXVfPOzCI4EFX06ZFDJ84kUSFDC7D_1t_wX9b7dvocxChqFm2wyfjvywc_n9JibQfftjKyAR4V2hhqfFs5UiSGSIgIoDTkquCUqO7AikMsXzWL6We8xdQ8c-HWy-CFi92XLeunjlkjCOfqRsZqYIB-pdwNIlCfC6-hQnov_Ggr_nbdbnM6mwpVnVtLy99IMhoe7RgJOs0bXBa6SqkNJHfMvsbWSQ8JfXxJUZXhusPf1cJ6nSkUcRTz3wbZ59cJHKjx33W_6jv4JHkFhtc8QrP_1qmP4N2KjlmfJFykHtOjHyQO4J8mKxQn_JC0XGQXlVW3O4C-rXDxmcK9RJTWhNC3MpVENg0g-Yg3nLpvjjuTiuHHagt4xsE0fNs3FQCDTUXeMVMYj3B-2K_5tMFGE8eiumTku1RiKuo89edY6odjqxQs1PPh5VEJUeOq_6ePGAurWNcCRDTT2BhM2rfGSVc7B3l7X7URBabkL4pcnBKbQcYlihw=w400
 
I made mine

I made my quadrant for my -4..its relatively easy, and I have the exact look I was after. I can't post pics (my firewall doesn't allow host sites) but I could send pictures to Email if your interested. I Mine is a 2 lever with pushbutton on throttle for smoke. Getting the geometry correct for travel is simple math, made from scraps of metal and phenolic for friction blocks.
 
One thing that nobody has done right is to have the mixture and prop on one pivot and the throttle on a different pivot. This way, you can cinch down the mixture and prop with one friction knob but have the throttle easier to move.
 
One thing that nobody has done right is to have the mixture and prop on one pivot and the throttle on a different pivot. This way, you can cinch down the mixture and prop with one friction knob but have the throttle easier to move.

The simple fix to get this desired behavior is to put larger plastic washers between the prop, mixture levers and the inner side, and a smaller set of washers surrounding the throttle lever.
 
One thing that nobody has done right is to have the mixture and prop on one pivot and the throttle on a different pivot. This way, you can cinch down the mixture and prop with one friction knob but have the throttle easier to move.

Dayton Murdock (DJM) has done this - one pivot point, but two concentric shafts with two friction levers. Works really well!
 
Dimensions, Please!

Thank you for the various suggestions and links, they're interesting.

What I'm looking for, though, are dimensions.

Thanks!

Dave
 
If you have the ?arms? on your throttle body you can measure the maximum travel. Then the only other information you need is the maximum travel of your cables. After that it is simply a matter of making a very crude mock up to check where the holes should go in the arms. Ideally you want the maximum travel.
In one of the posts toolbuilder had lengthened the mixture arm. This would likely mean a longer cable travel distance and perhaps a longer lever. A longer lever may require more depth in the quadrant. Thus it makes a lot of sense to do your own measurements. All quadrants are not the same.
 
I'm looking for dimension for the quadrants that we generally use on RVs. I have the carburetor lever deflection data and comparison data from my Cessna, which uses non-quadrant controls.

But I'd like to find dimensions for quadrants. They're a bit different.

Thanks!
Dave
 
Dayton Murdock (DJM) has done this - one pivot point, but two concentric shafts with two friction levers. Works really well!

Building a new throttle quadrant is on my long list of projects for my RV-8.

The P-51 quadrant had two locking levers - I believe it was concentric shafts but I'll have to look at the plans for the quadrant.

I'd like to make a copy of the -51 throttle with the mixture control at the 9 o'clock - 5 o'clock part (lower left) of the quadrant. I will start by taking a standard 3 lever system, and flip the mounting of the mixture lever.
 
All quadrants are not the same.

Exactly Tom, that is one of the reasons why I modeled it in Solidworks. Different arms and cabling dictate throws, and takes a bit of work to get it all right to where the mechanical stops hit before the stops at the quadrant.
 
Exactly Tom, that is one of the reasons why I modeled it in Solidworks. Different arms and cabling dictate throws, and takes a bit of work to get it all right to where the mechanical stops hit before the stops at the quadrant.

And that's exactly why I'm looking for some dimensions, to see what others have done. There are no end of concepts and prototypes - I'd like to see the dimensions for what works. I don't want to reinvent the entire wheel.

Thanks!
Dave
 
2 lever from Van's

I pulled mine apart to measure it...
From pivot to clevis hole is 3" giving cable travel of 2.25".
Pivot to handle is 7" and 4.5" respectively.
The slots are 4" long.
Hope that helps you Dave.

Russell
685wl3.jpg
 
You may want to wait and measure the governor arm throw after it is installed. I had to drill another hole on the throttle quadrant lever to accommodate the PCU5000 movement because I was not able to get full throw. I am sure it was due to my geometry.
 
And that's exactly why I'm looking for some dimensions, to see what others have done. There are no end of concepts and prototypes - I'd like to see the dimensions for what works. I don't want to reinvent the entire wheel.

Thanks!
Dave

I think you're going to find that other's dimensions will get you close but in the end you will have to determine if you are getting the requisite throw.
 
And that's exactly why I'm looking for some dimensions, to see what others have done. There are no end of concepts and prototypes - I'd like to see the dimensions for what works. I don't want to reinvent the entire wheel.

Thanks!
Dave

I think what people are telling you is that there are endless mechanical details that would make providing you "dimensions" worthless. My throttle pivot is at the floor, so the total travel of the lever dictates the ratio needed to move the throttle arm on the servo. The hole I want to use on the arm (and I even lengthened mine) then dictates the available travel of the cable assembly (which itself is a variable among manufacturers). Everything is dependent on everything else, so a custom solution is going to have to be figured out from the ground up.

I wanted as long a throttle lever as possible to minimize the perception of an "arc"... You may have other goals. Start with what feels good, then work the ratios from there. Easy stuff.
 
Well, thanks everyone. Especially the guy who PM'd me with data about his, and Russell, who not only provided the data I wanted but a disassembled look at the innards, too.

I'm hoping to incorporate a feature not found in commercial quadrants. I don't expect to save money but if I do, so much the better. I'm building an RV-3B more for the project than to have one, and the quadrant might make a nice part of the project. As I see it, since once in a while there's a hiatus while I'm waiting for something to happen (a machinist to finish something, epoxy to cure, parts to arrive, whatever), this will make a satisfactory fill-in task while giving me something I want anyway.

I already have all the device throw lengths from the carb and governor; thanks for reminding me about the governor, Axel. And I have comparative cockpit control movement distances from my C180, along with an idea of what I'd like to see carried over or changed with the RV-3B.

Michael, it was your quadrants that started me thinking about this. Yes, of course mine will need to be individually designed to suit, especially so for an RV-3B. In this thread I was simply hoping for an idea of the basic geometry of the commercial quadrants, more for comparison than from any plan to copy them.

Thanks again, and if anyone has similar data for any of the other brands of quadrant, I'd sure like to get it.
Dave
 
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Keep in mind that much of what drives quadrant design is "comonality"- the WW-II designs were often just a common OTS item. I have one of these vintage pieces laying around and you can flip data placcards to suit the airplane its mounted to. In other words, its kind of a one size fits all. When you "roll your own", you have the opportunity to taylor the ergonomics and kinematics to suit your particular situation. The short throw and exagerated arc of the typical military and "little airplane" quadrants is probably a nod to manufacturing a compact, inexpensive solution. And for me its entirely unsatisfactory.

So be cautious about copying the existing design elements - they all have built in compromises. Optimize every element to fit YOUR airplane, flying style and body motion.
 
One thing that nobody has done right is to have the mixture and prop on one pivot and the throttle on a different pivot. This way, you can cinch down the mixture and prop with one friction knob but have the throttle easier to move.
Not True Ed
I have a new Formation Quadrant that isolates the prop, mixture friction from the throttle friction, It will be on my web page soon
 
Dayton's Single Pivot, Concentric Shafts(friction adj)

This is what I'm looking for! Is this available somewhere? All those on DJMs site have a single friction adjustment....?

A diagram of the construction would be OK too; I don't mind building it myself...
 
Not True Ed
I have a new Formation Quadrant that isolates the prop, mixture friction from the throttle friction, It will be on my web page soon

Would you please supply a pointer to your web page? Or is it the "Builder Log" you list? I checked there but didn't see any "products"

thanks!
 
Hi Dave,

I'll probably be an early customer when Dayton has his new quadrant available. When that happens, you're welcome to take a look at my existing quadrant and/or use it for the basis of your own design. I'll keep you posted.

I'll be watching for Dayton's new offering as I don't have the skills or the time to fabricate my own. I'm hoping his has a throttle control that is slightly larger than the mixture and prop controls. I also like the idea of tightening the friction independently. A button or two might be nice, but not a dealbreaker.
 
I’m working with Flyboy’s to replace the classic wood slide quadrant on my -8.

I take it most choices are made by DJM?

The Flyboy model looks very nice and Blake offered to make me one for my fixed pitch, two lever.
https://www.flyboyaccessories.com/product-p/2110.htm

Is the new DJM website with current offerings up and running. I’m finding only broken links.
Axle, what model is yours?

I’m installing new cables at 600 hours now and working to make it better for formation, any other advise?
 
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Is the new DJM website with current offerings up and running. I?m finding only broken links.
Axle, what model is yours?

I spoke with Dayton. He has not updated his webpage. I have the 3 lever, round top, dual adjustment knob.
 
I plan to use McFarlane's Mixture Cable

I'd originally figured on making my own throttle quadrant mostly to incorporate a fine adjustment to the mixture control. I still plan to make my own throttle quadrant with either just the throttle or that plus the prop control. I wanted to follow up on this thread about my plans.

For the mixture control, I'll use one of McFarlane's propriatary vernier-assist cables. I called them and it has a resolution of about .063 per turn, which I think might be fine enough.

The throttle control will be fairly normal and not include a fine adjustment feature.

Andy Hill used a vernier prop control mounted on the left spar bulkhead side, I think, and reported that the location was good. After I figure out where to locate the mixture control, I'll decide about that.
 
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