What throttle setup do you use?

[gregpro50 64]

Just curious what throttle setup you prefer for a dual carb motor?

Right now I've got a vernier throttle that attaches to a metal push-rod with two individual cables going to the individual carbs.

I don't think I like the push-button throttle setup.

Digging around on the internet I found this throttle setup that seems like the best of both worlds.  It eliminates the metal push-rods and goes right to the carbs to simplify things.

Anyone using this?  What do you think?

http://mcfarlaneaviation.com/Products/?CategoryID=343&PartNumber=MCTV0005D048&

[efil 01 74]

i'll use original avid, imo the throttle you want was not created when avids were new... it seems good, but i guess the travel will be inverted .. after that , it is a question of money 

 

Manu

[Av8r3400 1179]

I have the old or standard style McFarland throttle and choke cables on my Mangy project. They are expensive, but IMO worth every penny. They are extremely high quality units. 

The vernier one would be even better!

Edited 8 Dec 2015 by Av8r3400

[dholly 718]

I never liked the idea of a throttle belcrank on these planes. My 912uls has the Euro version equivalent of McFarland's dual cable vernier with throttle lock and I think it is superior in every way. Very smooth operation. My A+ will have one as well!

[wypaul 448]

I went with the ACS 05-06387 which is friction lock and about $60 less than the McFarlane.  Not a fan of the vernier with the pushbutton personally but it does have some advantages for some folks.  Not sure if I ended up with the 4 or the 6' for mine. Ran mine without the full throttle spring setup for about 250 hrs and liked that but now have a very light weight spring that will still allow it to creep to full throttle without making the throttle jerky on the ramp.  That is probably why I didn't like the vernier/push button setup. 

[gregpro50 64]

So how could I bypass the bellcrank so the throw is not inverted? 

[Av8r3400 1179]

So how could I bypass the bellcrank so the throw is not inverted? 

I don't understand the question.  

[Emory Bored 61]

I have seen that McFarland and liked it.  Dholly speaks for me on the spring tension and throttle setup.  What I don't like about the long belcrank setup is that all the small tolerances add up and make it just a little tougher to sync the carbs.  

[wypaul 448]

The original "bellcrank" did not invert or reverse, so the cable works just right, push to full throttle.

[efil 01 74]

 paul  : i've just intalled throttle on my avid and see clearly that when i push, the bellcrank pull the cables to open carb

[Emory Bored 61]

You can swap the levers on the carburetors to either pull or push, or build a new bell crank with all three arms on the same side of the horizontal rod. 

[gregpro50 64]

So how could I bypass the bellcrank so the throw is not inverted? 

I don't understand the question.  

Right now when I push the throttle it pushes on the bellcrank and two cables pull the throttle open.

If I hookup the new cable directly now I would have to push for idle and pull for throttle.

Its probably an easy fix by swapping arms or something but the plane is at the hangar and I just can't figure out the mechanics in my head right now without looking at it.

As mentioned the small tolerances add up with the current setup and makes it difficult to get a good carb synchronization.  I'd like to bypass it and cable directly to the carbs.

[Av8r3400 1179]

The 912 has a great design in that there are springs to pull the throttles open and the cable pulls a against them for idle.  If a cable breaks, you still have power to manuver, using the ignition to stop the engine for landing.  

By reversing this (spring to idle), if you loose a cable you have a much greater power off emergency. 

These types of cables are NOT designed to push. 

[wypaul 448]

 paul  : i've just intalled throttle on my avid and see clearly that when i push, the bellcrank pull the cables to open carb

 

 

True for the 582 but the 912 is rigged different if it was sold with 912.  See Larry's explanation above.

So how could I bypass the bellcrank so the throw is not inverted? 

I don't understand the question.  

Right now when I push the throttle it pushes on the bellcrank and two cables pull the throttle open.

If I hookup the new cable directly now I would have to push for idle and pull for throttle.

Its probably an easy fix by swapping arms or something but the plane is at the hangar and I just can't figure out the mechanics in my head right now without looking at it.

As mentioned the small tolerances add up with the current setup and makes it difficult to get a good carb synchronization.  I'd like to bypass it and cable directly to the carbs.

If you have the manual handy look in Section IV D-912 Chapter 4 page 3, this is how the throttle arm is rigged, as Larry has discribed with the springs pulling the throttle open when you firewall the throttle open. A picture of the belcrank is on page 8 of chapter 5.  If your's is not rigged as discribed let me know and I will take a closeup of the throttle arms for you today while at the hanger.  I may have posted section IV for the 912 on this forum if you do not have it, I will look and let you know.

[wypaul 448]

The 912 chapter that I posted is in the "Files and Forms" section.  

 

 

Here is the complete Mark IV 912 Rotax  installation Manual Section IV Chapters 1-7 from Avid dated 11/2/1992.  These are in the tiff format.

Sect IV Ch 1.tiff

Sect IV Ch2.tiff

Sect IV Ch3.tiff

Sect IV Ch4.tiff

Sect IV Ch5.tiff

Sect IV Ch6.tiff

Sect IV Ch7.tiff

[tcj 150]

I sense some confusion about reversing the push throttle.  Rotax two strokes require a bell crank to reverse the standard aircraft push throttle to pull the carb slides open.  To eliminate the bell crank on a two stroke set up a throttle like the one at the top of this page would be needed http://www.aerocontrols.net/Throttle Quadrants.htm#THROTTLE_QUADRANTS

You would still need a splitter to convert to two cables.  Without oil injection, two cables  http://www.aerocontrols.net/ac__200__series.htm

or with oil injection, three cables  http://www.aerocontrols.net/ac__300_series.htm

I know nothing about the 912 engines,

[Emory Bored 61]

The 912 has a great design in that there are springs to pull the throttles open and the cable pulls against them for idle.  If a cable breaks, you still have power to manuver, using the ignition to stop the engine for landing.  

By reversing this (spring to idle), if you loose a cable you have a much greater power off emergency. 

These types of cables are NOT designed to push. 

This is true of course but I wonder how often these cables break in flight and what could be done to mitigate that possibility?  Preflight inspection?  Inspect at oil change?  In any case do the cables break as often as airplanes equipped with spring to open throttles take off across the ramp banging into stuff?  Friction locks fail too in my experience.  I dunno.  Just asking.  

[wypaul 448]

Sorry Greg, you have a Kitfox so that may be different but if you refer to the Avid manual you can see how it is setup.  Also the photo offer stands.

[gregpro50 64]

Never mind.  I was making a big deal out of nothing.  I think I was looking at the bellcrank for a different setup in the manual.  After looking at the plane today mine does not invert the setup.  The cable change will just be a plug and play.  I'm going to go ahead and order it.