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  #11  
Old 11-18-2012, 06:57 PM
woodsideraff woodsideraff is offline
 
Join Date: Aug 2007
Location: Aiken, SC
Posts: 122
Default Now I'm really confused!

Is it just the friction lock that holds the throttle back counter-acting the springs, or is there a firm lock that releases when the throttle is pushed or pulled? If it's just the friction lock holding the throttle from moving, then I can't see how this is any better in keeping the springs from creeping the throttle up. One just gets the added feature of vernier adjustment, but would still have to override the friction to make course adjustments.

I'll call McFarland in the morning for a clarification.

Cheers,

Rafael
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  #12  
Old 11-18-2012, 08:37 PM
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Jetguy Jetguy is offline
 
Join Date: Aug 2008
Location: Texas, Fort Worth
Posts: 1,216
Default It works this way.

The McFarlane Vernier Assist Rotax throttle works this way. First you have to also buy, if not included, the McFarlane replacement Rotax throttle arm springs part number 6696. If you don't use the springs the Vernier Assist throttle will not work correctly. With the tension lock nut all the way tighten all this does is keep the throttle from creeping forward. It does not lock the throttle from moving. The pilot can still push or pull the throttle. At this point it acts like a regular throttle like on a C-172 or C-152/150. Also at this point if you wish to make fine adjustments all you have to do is twist the throttle to move it in or out very slowly. Hence the phrase, "Vernier Assist".
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RV12 N1212K
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  #13  
Old 04-12-2013, 07:58 PM
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Tony_T Tony_T is offline
 
Join Date: Dec 2008
Location: Seattle, WA
Posts: 1,171
Default McFarlane Throttle installed...

I installed the McFarlane Throttle and also the springs that came with it. I found a couple of installation issues that no one else has mentioned so here is my experience.

First, the throttle installs in a 3/4" diameter hole so you will need to open the stock RV-12 panel hole to 3/4". After doing so, I found that there is not a lot of clearance to the bottom of the instrument tray for the larger retaining nut on the new throttle control.


I had to file off the corners of the nice red anodized nut:


And make a flat on the lock washer, too:


After this shade tree mechanic work the throttle went in OK:


The throttle comes with matching springs, no doubt important to the proper operation of this vernier setup. Seen here installed with a comparison to the stock spring:


Once installed along with the matching springs, the throttle works very nicely. You use it much like the original by setting the friction as you like, but now it takes less friction. Then you can push or pull the throttle or turn the knob for small movements. It is really cool to turn the vernier and watch the throttle arms slowly move.


It was raining at the airport today so I did not do a carb sync or fly the plane with the new throttle but I expect it to be a nice improvement in quality of flying, and I consider it a safety improvement as well. No more "fighting the machine", as my pal Bob calls it.

Tony
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Last edited by Tony_T : 04-17-2013 at 09:43 PM. Reason: corrected spelling
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  #14  
Old 04-12-2013, 09:58 PM
NASA515 NASA515 is offline
 
Join Date: Nov 2011
Location: Hansville, Washington
Posts: 536
Default

Hey, "Shade Tree", you is 'da Best. Sorry I missed your, 'er, swearing session. After Monday, I will have rendered unto Caesar, and can resume doing my own thing. I'd like to watch/help you re-balance your carbs, etc etc.

Bob
N737G
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  #15  
Old 04-13-2013, 01:51 PM
aerofurb aerofurb is offline
 
Join Date: Jul 2009
Location: High Wycombe, UK
Posts: 278
Default

We've got 10 hours or so on the new throttle cable (35 hours before the mod) and it's a superb bit of kit that transforms the engine handling.

Remember this isn't a vernier control in the normal sense. The vernier action is engaged by turning the friction lock, slacken the friction lock and it's a normal push/pull action that isn't trying to countersink itself through the instrument panel the moment your grip twitches

If you do the mod then you will not be disappointed and I would hope that Van's adopt this control as the standard issue part - even if it is a few dollars more.

Only snags were the clearance issues during installation that Tony detailed above.

Okay, so the carbs need setting up but that's worth doing periodically anyway.

Well done McFarlane!
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  #16  
Old 04-13-2013, 03:19 PM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 2,523
Default Moving a hole

Instead of enlarging a hole concentrically, I have enlarged and moved a hole to the side using a file. I file the hole slightly under size, then final drill with the desired final size drill bit.
This same trick works on smaller size holes too. If the pilot hole is slightly off center, file it on one side, then final drill.
Joe Gores
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  #17  
Old 04-13-2013, 04:21 PM
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engineerofsorts engineerofsorts is offline
 
Join Date: Mar 2009
Location: Austin, Texas
Posts: 293
Default Lazy engineer's approach

When installing my vernier throttle, after enlarging the hole with a step drill, I took out the screws holding the center panel in, allowing me to tighten the (unmodified) nut, being careful to tighten it such that the top face of the nut was horizontal. There was enough clearance to then replace the center panel, with the bottom of the panel serving as a secondary locking mechanism.
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  #18  
Old 10-19-2017, 03:42 PM
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DonFromTX DonFromTX is offline
 
Join Date: Oct 2010
Location: La Feria Texas
Posts: 3,617
Default Review of Old Thread

I flew Jetguy's 12 with the MacFarlane and loved it. I have one to install on my 756TS plane, but standing between the wing and a whirling prop in my old age unsteady stance worries me. I can see no reason that I cannot measure the opening with a precision caliper, then adjust to repeat the previous measurements. Am I just doing wishful thinking, or is this feasible?
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  #19  
Old 10-19-2017, 04:06 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,972
Default

Quote:
Originally Posted by DonFromTX View Post
I flew Jetguy's 12 with the MacFarlane and loved it. I have one to install on my 756TS plane, but standing between the wing and a whirling prop in my old age unsteady stance worries me. I can see no reason that I cannot measure the opening with a precision caliper, then adjust to repeat the previous measurements. Am I just doing wishful thinking, or is this feasible?
If you are talking about taking measurements to make throttle adjustments normally completed while doing a carb. synchronization?

Yes, it is wishful thinking. No, it is not feasible.
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  #20  
Old 10-19-2017, 04:40 PM
BigJohn BigJohn is offline
 
Join Date: Nov 2008
Location: Gloversville, NY
Posts: 1,470
Default

Quote:
Originally Posted by DonFromTX View Post
I flew Jetguy's 12 with the MacFarlane and loved it. I have one to install on my 756TS plane, but standing between the wing and a whirling prop in my old age unsteady stance worries me. I can see no reason that I cannot measure the opening with a precision caliper, then adjust to repeat the previous measurements. Am I just doing wishful thinking, or is this feasible?
Don, you do not need to make adjustments with the engine running. Get someone to help you. You stay in the cockpit and take the readings on the Carbmate or the instrument of your choice, then shut down and have your helper make very small adjustments to the throttle lingages, and repeat the process. A few iterations and you are done!

BTW, have you made any progress with your medical/training issues?
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