What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Vernier Throttle

E

Ex Bonanza Bucko

Well Known Member
I heard that Van's would release a vernier throttle for the RV12 S-LSA pretty soon. Do you have any good info about that?

Thanks,
EBB
 
McFarlanes released a new design vernier-assist throttle some time ago that some builders have installed. Based on recent plans amendments, I have an idea that Van's may have switched to this in the current kits, although I could be wrong.
 
If you have an S-LSA you can't install anything to the airplane not approved by Vans because that would void the Special Airworthiness Certificate. If Van's approves the McFarlane throttle that would make it legal. If they didn't I can't use it.
Thanks,
EBB
 
Yes, that's right. Their standard throttle is made by McFarlanes too, so it may be worth asking them.
 
I really like the vernier throttle controlling the Rotax engine. I think it would be a great option to have in the 12 vs. the current one.
 
I have been flying with one from day one in my RV12. I had one of the first ones they produced. It is smooth and works great :D
 
My first ride in a 12 was with a vernier throttle, boy was I surprised when I picked up my SLSA with that "factory" throttle.
I voiced my disappointment to Van's but got some story how it wasn't approved by Rotax?..funny how many other LSA's and SLSA's have vernier throttles with rotax power.
Anyway I hope it becomes approved for SLSA's soon, I want one.
 
I have tried several weaker springs, and one set failed due to work hardening from forming a new hook after cutting down the length. I finally found a set at Home Depot that provide smooth action without creeping. FYI, the throttle cables were stiff enough to operate the carbs when the one set failed. There has been some discussion about the wisdom of replacing the springs, but I am happy with my current set up, and I found the previous failed set on preflight, not due to any rough engine or loss of power. Just passing on my operating experience. I am sure many still doubt the wisdom of going to weaker springs.
 
McFarlane's package includes weaker springs

RFSchaller said:
I have tried several weaker springs, and one set failed due to work hardening from forming a new hook after cutting down the length. I finally found a set at Home Depot that provide smooth action without creeping. FYI, the throttle cables were stiff enough to operate the carbs when the one set failed. There has been some discussion about the wisdom of replacing the springs, but I am happy with my current set up, and I found the previous failed set on preflight, not due to any rough engine or loss of power. Just passing on my operating experience. I am sure many still doubt the wisdom of going to weaker springs.
Click to expand...

I installed McFarlane's Vernier throttle on our RV-12 last year. The package from them included the weaker springs, which were basically required to properly work with the vernier.
 
I have had 3-4 RV12's install McFarlane throttles over factory to hold a better set point. It was easier to do a carb sync and make it stay in one place too.
 
Just flew 412 with Mike S

Just flew 412 on Friday and it had a new throttle and weaker springs.....it is not the push button type, but a friction adjustable vernier that is rotatable for smaller throttle adjustments. Seemed to work nicely and I think I heard it will be around a 180 option available thru Vans with weaker springs for builders looking at the newer section revisions. Hardly touched the friction adjust at all.

Also had the Skyview touch installed as well.
 
Last edited:
I installed the vernier throttle in N112VA (the Garmin G3X Touch airplane which I'm bringing to OSH) a few months ago. A vast, vast improvement over the standard throttle/spring arrangement.

Over my hundreds of demo flights in the RV-12, many folks have asked if there was anything I didn't like or would want to change on the 12. I always responded that the throttle was a weak area. It isn't now.
 
MLock said:
I installed the vernier throttle in N112VA (the Garmin G3X Touch airplane which I'm bringing to OSH) a few months ago. A vast, vast improvement over the standard throttle/spring arrangement.

Over my hundreds of demo flights in the RV-12, many folks have asked if there was anything I didn't like or would want to change on the 12. I always responded that the throttle was a weak area. It isn't now.
Click to expand...

Just to reiterate - that's a mod you can do AFTER the phase 1 flyoff, correct?
 
I just picked up a new SLSA and am on the long flight home. my hand and fingers are really sore from having to use the throttle with almost full friction lock on to avoid the throttle moving forward rapidly if I take my hand off for a second.

when I ordered the plane I specifically took Mitch,s suggestion about the vernier throttle. van,s usual response is " I ,s still in engineering" however they did tell me that the "new springs" were are big improvement. I didn't,t get them because the original batch had metallurgical issues and had to be sent back however I can order them when they come in .

quite frankly the throttle , for me, is a huge pains in the rear and along with the rudder pedals being non adjustable is the biggest gripe I have. I saw Vans are saying they are close to producing a mod for the pedals as well as dual screens.

BTW..the Skyview Touch with ADSB in and out is great . I also have the Seattle sectionals installed and it's nice to be able to switch. Between the Dynon chart and the sectional chart to cross check.

Two more days......
 
Top Cat said:
I just picked up a new SLSA and am on the long flight home. my hand and fingers are really sore from having to use the throttle with almost full friction lock on to avoid the throttle moving forward rapidly if I take my hand off for a second.

when I ordered the plane I specifically took Mitch,s suggestion about the vernier throttle. van,s usual response is " I ,s still in engineering" however they did tell me that the "new springs" were are big improvement. I didn't,t get them because the original batch had metallurgical issues and had to be sent back however I can order them when they come in .

quite frankly the throttle , for me, is a huge pains in the rear and along with the rudder pedals being non adjustable is the biggest gripe I have. I saw Vans are saying they are close to producing a mod for the pedals as well as dual screens.

BTW..the Skyview Touch with ADSB in and out is great . I also have the Seattle sectionals installed and it's nice to be able to switch. Between the Dynon chart and the sectional chart to cross check.

Two more days......
Click to expand...

Cool, hope the rest of your flight home is smooth. I've got around 60-70hrs on my SLSA and I've gotten somewhat used to the throttle but I will still be first in line if Van's approves it for the SLSA!
 
Throttle

I couldn't agree more with you guys and I certainly understand how that long trip home with that thing is a real pain.

I think Van's has an urgent business need to fix the throttle; people are not going to buy the S-LSA very fast with that thing installed. Apparently the Experimental world can just fix it but we S-LSA guys have to wait and it's pretty hard to understand how the Experimental vernier throttle is somehow dangerous and can't be used on our airplanes.

I love my S-LSA but I certainly would love it more with a vernier throttle.....might be somewhat safer too.

EBB
 
You can always change your S-LSA to E-LSA. Then you can do what you want.
 
Ex Bonanza Bucko said:
I love my S-LSA but I certainly would love it more with a vernier throttle.....might be somewhat safer too.

EBB
Click to expand...

It is coming.

Unfortunately, it is a little more complicated to make a change for the S-LSA airplanes than simply handing them a different part and a different construction manual page for installing it.

Part of the delay was our discovery of a fatigue failure problem with the newer version spring being supplied by Mcfarlane (You can see the service Bulletin HERE).
 
The McFarlane SB calls for "locally annealing" the new spring. That is not good enough! And I now can see why Van's has this problem in engineering: They can't rely on S-LSA owners to "locally anneal" a spring. Geez! That might....MIGHT.....be OK for an ELSA builder but Van's has a Special Airworthiness Certificate on the S-LSAs that precludes this kind of stuff. Somebody needs to have a long talk with McFarlane.....if that hasn't already happened.


EBB
 
I believe the SB reference to locally annealing refers to a localized area of the spring. The new part number appears to be ready to install. Mcfarlane is a quality manufacturer of certified parts and appears to have been proactive in adressing the issue.
 
The SB states the following:

"McFarlane Aviation has addressed this issue by redesigning the part to require locally annealing the work hardened areas. For clarity, a new part number (6818) has been established. P/N 6818 may be easily identified by the presence of a blue or green stripe applied to the side of the spring coil."

To me that means that PN 6818 is required to be locally annealed in the work hardened areas. It also means to me that the new part is not ready to instal until it is annealed.
 
Ex Bonanza Bucko said:
The SB states the following:

"McFarlane Aviation has addressed this issue by redesigning the part to require locally annealing the work hardened areas. For clarity, a new part number (6818) has been established. P/N 6818 may be easily identified by the presence of a blue or green stripe applied to the side of the spring coil."

To me that means that PN 6818 is required to be locally annealed in the work hardened areas. It also means to me that the new part is not ready to instal until it is annealed.
Click to expand...

I'm with Scott....what's McFarlane's problem I.e. Simply replace the defective springs with "properly" manufactured ones. To trust that "locally" annealing has corrected the problem wouldn't fix my pucker factor!!!
 
I suspect that McFarlane 's "locally annealing" refers to a spot on the spring the manufacturer "locally" annealed -- not having it done at your "local" annealing shop. ;)
 
If that is true we have yet another example of the need to require passing "bone head rhetoric" for any tech weenie to graduate from anything above the 4th grade. :)
EBB
 
Ex Bonanza Bucko said:
If that is true we have yet another example of the need to require passing "bone head rhetoric" for any tech weenie to graduate from anything above the 4th grade. :)
EBB
Click to expand...

Bruce,
I am not sure how you got the idea that owners would need to anneal their springs. My guess would be that you are not accustomed to reading aircraft Service Bulletins. The one in question is pretty typical in the way it is formatted.

It specifically says a certain part # spring should be replaced (and then destroyed) with a new part # spring that can be identified by a paint stripe on the side.
Pretty simple really.
I just pointed out the SB as an FYI.

Anyone not clear on what it means should possibly call McFarlane or consult with the mechanic they use for their RV-12 to determine if they are effected.
 
Last edited:
Thanks but:

It would be better if people who write this stuff assumed that the readers are not accustomed to reading the language of SBs; most of us just buy and fly the airplanes and usually don't work on them but we still need to understand what is said about them by vendors. It would have been a lot more plain had McFarlane said words to the effect that "We will locally anneal the part where it was weakened;" or "McFarlane will supply the new part number with the weakened spring in the spot that was weakened." Etc.

I think shorthand and insider language is potentially dangerous. At the very least the language chosen would provide fertile ground for a ambulance chasing lawyer in a suit over an accident caused by a broken spring. We don't need more lawyers but we need to remember that they passed bonehead rhetoric.

EBB
 
I am not in the position to defend how McFarlan chose to word their SB, but it seems reasonable to wonder why they would say they will supply a new spring ( with a new part number) but then expect the customer to go have it annealed?
If that were the case, couldn't they have just told everyone to have the springs they already have, annealed?
 
Scott:
That would have been reasonable and I probably should have tumbled to that. But I have gotten used to more misleading words than those here and other places inhabited by people who are not required everyday to be understood.

I think jargon is among the worst language we find on web pages and in ads directed at zealots and aficionados...and there is usually a lot of it.
EBB :)
 
Springs and Service Bulletins

In response to those confused by the McFarlane Service Bulletin SB-6 containing the throttle springs, I would first recommend you open a copy of the original document which can be found on our website here:

http://server1/Reference/default.aspx?ID=84744206&page=Content&Article=88

To be clear if you have a spring with a stripe on it from McFarlane and it came in a package labeled with part number 6818. It is already annealed DO NOT ANNEAL YOUR SPRINGS.

The talk of annealing is covered in the Background section of the service bulletin. This helps the end user understand the "why" and "what" happened involving the part, and it is a pretty standard format for service bulletins.

As you read further under the Accomplishment Instructions section, it tells you how to go about replacing your springs and it does not involve annealing in any way shape or form.

Just follow the instructions listed in the Accomplishment Instructions section in order and both you and your springs will be happy.

Thanks!
 
Last edited:
fyi

I just received an unsolicited email from Mcfarlane that new spring will be shipped tomorrow for my throttle cables on my Rans S19. This is what I call good service!
 
You must log in or register to reply here.
Back
Top