RV 12 ELSA Dual Throttle On 912 ULS?

Captain Cowboy · #1 05-22-2018, 09:39 PM

We built a 12 ELSA with a single throttle per specs, then after FAA Cert. modified it with a Vernier Throttle. We now have need for a second throttle to the left of the pilot using the left seat. Does anyone have info/pics/data/suggestions as how to put the second one on the a/c using both Bing Carbs and syncing both throttles and the linkages. Thanks in advanced for your ideas! Doug Robison, email is--MarkPSU13@aol.com

hufise · #2 05-23-2018, 12:32 AM

The most people have a left arm to handle the throttle

And it works

Daniel #120383 500hrs

rongawer · #3 05-23-2018, 06:27 AM

Two throttle controls for the same engine? Even if you could come up with a “rube goldberg” type spring & lever assembly, which throttle control would be the master? Disregarding any means that it could be implemented, the words “fraught with peril” come to mind..

I suppose you could use some sort of fly-by-wire rheostat and servo assembly, I’d have to give that some thought.

I rarely am the naysayer, but on this one, I ask you to reconsider.

There’s a reason the throttle is universally in the center, for access to both pilots.

vic syracuse · #4 05-23-2018, 08:24 AM

Sure it could be done, but I think you would be complicating a system that really needs to be tight in order to keep the carbs sync'd.

But, just in case you are asking due to a handicap, a way to do it would be to make a bracket behind the panel which would hold a tube with 3 (or 4) arms on it. This tube would be the width of the 2 cockpit throttle locations, and each of those throttles would attach to their respective arm on the tube. Then, another arm (or 2) would attach the cable (s) to the carbs. You would need one arm on the tube if using a dual cable, and 2 arms if using separate cables.

It would be really easy to fabricate, and not add much weight. I'm sure someone on this forum could 3 D print it for you.

Vic

EXflyer · #5 05-23-2018, 08:25 AM

Thought way back when the RV6 came out there was some chatter about that. It would have been, well way back, before the internet. Yes there was a time that was true. Don't know but think there was a news letter back then for the three models they had. RV3,4 & 6.

rvbuilder2002 · #6 05-23-2018, 09:32 AM

Quote:

Originally Posted by vic syracuse

Sure it could be done, but I think you would be complicating a system that really needs to be tight in order to keep the carbs sync'd.

But, just in case you are asking due to a handicap, a way to do it would be to make a bracket behind the panel which would hold a tube with 3 (or 4) arms on it. This tube would be the width of the 2 cockpit throttle locations, and each of those throttles would attach to their respective arm on the tube. Then, another arm (or 2) would attach the cable (s) to the carbs. You would need one arm on the tube if using a dual cable, and 2 arms if using separate cables.

I agree with Vic. This would be the only way I can think of to do it.
It is the basic concept that may of the Zenith airplanes have used over the years. They have a throttle on each side because they used a central control stick between the seats. You could find someone with one of those airplanes to see how they do it.

Mel · #7 05-23-2018, 09:51 AM

Quote:

Originally Posted by rvbuilder2002

It is the basic concept that may of the Zenith airplanes have used over the years. They have a throttle on each side because they used a central control stick between the seats. You could find someone with one of those airplanes to see how they do it.

I actually did this when I built a Zenair 601HDS except I used pushrods from the "bellcrank" (forward of the firewall) to the carbs because I don't like the cables. This also removes the springs that pull the throttle to wide open. Movement of the engine is very minor and is sideways in nature so having the pushrods running from the firewall to the engine work well. This aircraft now has over 1900 hrs on it with virtually no problems.

Captain Cowboy · #8 05-24-2018, 02:46 PM

Thanks to all who responded, I had a stroke 4 years ago and can fly from the right seat easily, I thought that someone else might be in need of the info as it is easier to view/interpret the D180 data siting in the left seat using the left stronger arm for power control. Thanks Mel for your info as I may use some of it if and when I decide to modify my 12. Again, thanks to all, your thoughts/ideas are much appreciated!!! Doug Robison 120254