Throttle Quadrant for Rotax 503

Brian Jackson

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Jul 17, 2004
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Hamburg, New Jersey USA
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GyroBee Variant - Under Construction
Greetings.

Sorry I don't post as often as usual, but construction on the gyro is still happening. It's time to install a throttle quadrant but I do not know much about selecting one for the 503. Number of levers, cable travel distance, etc. If anyone has been down this path I'd be grateful for their input. There's usually more to things than their deceptive simplicity might suggest. Thanks in advance.

Brian
 

Aerofoam

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Az.
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Pteradactyl, AC 447/503, too many UAVs
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Over 3k....(From the ground !)
I'm drooling just a little bit...
What is the price range on those?
Mine is very stiff and has no choke....
 

All_In

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Airgyro AG915 Centurian, Aviomania G1sb
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Gyroplane 70Hrs, not sure over 10,000+ logged FW, 260+ ultralights, sailplane, hang-gliders
I'm drooling just a little bit...
What is the price range on those?
Mine is very stiff and has no choke....
$72.30 for the single lever.
$74.60 for the dual lever.
 

Capt'n Gator

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Sep 25, 2012
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554
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Goldsboro, NC
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Dominator Single 582BH N401JC
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150+
I am using these throttle quadrants on my Dominator and I Love it, I have a dual quadrant with one lever being long with a t handle (THROTTLE) and the other lever short with a red ball handle that engages my new GYRO TECHNICS hydraulic prerotator which works so much better than the original Rotor Flight Dynamics prerotator. I will post pictures this weekend.
 

Brian Jackson

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Hamburg, New Jersey USA
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GyroBee Variant - Under Construction
I am using these throttle quadrants on my Dominator and I Love it, I have a dual quadrant with one lever being long with a t handle (THROTTLE) and the other lever short with a red ball handle that engages my new GYRO TECHNICS hydraulic prerotator which works so much better than the original Rotor Flight Dynamics prerotator. I will post pictures this weekend.
Thank you everyone. Gator, sounds like the setup I'm envisioning for mine. Have been watching Denis' developments and will be calling about his prerotator kit. Looking forward to your photos. Cheers.
 

Doug Riley

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Jan 11, 2004
Messages
6,752
Brian, we cheapskates have been making them from scratch for decades. As you can see from the catalog pics, a quadrant throttle is simply a strip of metal (1/8" 6061-T6 will do) with a handle on one end, a pivoting cable fitting on the other, and a pivot in between. The central pivot should have adjustable friction, which can be supplied by nylon washers and pressure applied by tightening and loosening the central pivot's nut-bolt assembly.

To make it cool-looking, you can add any kind of fine hardwood or chrome knob that you like.

My Tandem Dominator came with a varnished wooden handle on its throttle that I'm certain began life on a hibachi grill. Probably bought at Walmart Aerospace.

Ken Brock's throttles were a bit more sophisticated. They used a pulley mounted on the handle, so that the cable wrapped around rather than being pulled in a straight line. This idea (borrowed from motorcycle twist grips) makes a very long throttle arc possible -- 180 deg. or more if you want. The simple version obviously has diminishing returns if the throw is more than 90 deg. or so -- and locks up and goes over-center if it travels a long enough arc.

T.M.I.?
 

Brian Jackson

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Hamburg, New Jersey USA
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GyroBee Variant - Under Construction
Brian, we cheapskates have been making them from scratch for decades. As you can see from the catalog pics, a quadrant throttle is simply a strip of metal (1/8" 6061-T6 will do) with a handle on one end, a pivoting cable fitting on the other, and a pivot in between. The central pivot should have adjustable friction, which can be supplied by nylon washers and pressure applied by tightening and loosening the central pivot's nut-bolt assembly.

To make it cool-looking, you can add any kind of fine hardwood or chrome knob that you like.

My Tandem Dominator came with a varnished wooden handle on its throttle that I'm certain began life on a hibachi grill. Probably bought at Walmart Aerospace.

Ken Brock's throttles were a bit more sophisticated. They used a pulley mounted on the handle, so that the cable wrapped around rather than being pulled in a straight line. This idea (borrowed from motorcycle twist grips) makes a very long throttle arc possible -- 180 deg. or more if you want. The simple version obviously has diminishing returns if the throw is more than 90 deg. or so -- and locks up and goes over-center if it travels a long enough arc.

T.M.I.?
Thank you, Doug. Good to hear from you my friend, and great info. If going the DIY route I'm guessing the first thing to consider is the linear travel distance of the cable itself. Once known it will be easy to work out the geometry. Will have to measure the engine throttle's mechanical range as the basis for lever length, etc.

I should post more pics of the gyro build but have kinda held back on the photography a bit lately. Figured people have already seen enough lathing and milling pics. Some big money-shots coming soon though. Cheers.

Brian
 

Doug Riley

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6,752
Exactly right, Brian. The carb's total cable travel, and the arc you'd like the handle to cover. And how much non-linearity you can tolerate at the ends of travel. That's if you use the simplest setup in lieu of Ken Brock's pulley design.

Bit o' trig involved, but all in good fun.
 

Brian Jackson

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Hamburg, New Jersey USA
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GyroBee Variant - Under Construction
Exactly right, Brian. The carb's total cable travel, and the arc you'd like the handle to cover. And how much non-linearity you can tolerate at the ends of travel. That's if you use the simplest setup in lieu of Ken Brock's pulley design.

Bit o' trig involved, but all in good fun.
Good to know, Doug. Sounds pretty straight-forward. Will model it up a few different ways and get a better feel of which way to go (pulley or linear). There's a plate that runs under the seat tank I've left long on the left side of the seat for mounting a throttle quadrant. Would be nice to simply slot it for levers and let the plate itself be the quadrant. Will flesh it out and share the design idea here for critique.
 

Capt'n Gator

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554
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Goldsboro, NC
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Dominator Single 582BH N401JC
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150+
ok, as promised here are some pictures of my new Baxter Throttle Quadrant (888-573-2580) and my new Gyro Technics Hydraulic Prerotator. If you order direct from Baxter you can get options versus if you order from Aircraft Spruce. I ordered what they call their large quadrant which gives a longer throw on the handles which you will need for the prerotator and also I ordered the attachment plate for feeding the cables through and i also ordered the larger hole in the side of the quadrant which makes it easier to attach your cables to the handles. Also ordered it with the tensioning knob. Denis makes a fantastic prerotator and I have the first one that attaches to the hydraulic motor. I also attached my radio bracket to the front of the quadrant.
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Brian Jackson

Platinum Member
Joined
Jul 17, 2004
Messages
3,374
Location
Hamburg, New Jersey USA
Aircraft
GyroBee Variant - Under Construction
ok, as promised here are some pictures of my new Baxter Throttle Quadrant (888-573-2580) and my new Gyro Technics Hydraulic Prerotator. If you order direct from Baxter you can get options versus if you order from Aircraft Spruce. I ordered what they call their large quadrant which gives a longer throw on the handles which you will need for the prerotator and also I ordered the attachment plate for feeding the cables through and i also ordered the larger hole in the side of the quadrant which makes it easier to attach your cables to the handles. Also ordered it with the tensioning knob. Denis makes a fantastic prerotator and I have the first one that attaches to the hydraulic motor. I also attached my radio bracket to the front of the quadrant.
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Beautiful setup, Capt'n Gator. Thank you for posting the photos and for the great descriptions. Curious what brakes you're using in that last photo.
 

Resasi

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100+ gyro, 16,000+ other
ok, as promised here are some pictures of my new Baxter Throttle Quadrant (888-573-2580) and my new Gyro Technics Hydraulic Prerotator. If you order direct from Baxter you can get options versus if you order from Aircraft Spruce. I ordered what they call their large quadrant which gives a longer throw on the handles which you will need for the prerotator and also I ordered the attachment plate for feeding the cables through and i also ordered the larger hole in the side of the quadrant which makes it easier to attach your cables to the handles. Also ordered it with the tensioning knob. Denis makes a fantastic prerotator and I have the first one that attaches to the hydraulic motor. I also attached my radio bracket to the front of the quadrant.
View attachment 1155461
img_0661-jpg.1155462
View attachment 1155463
That looks sweet, nice set-up Gator.
 
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