Mcfarlane throttle

[Dutch]

I am looking in to the MCFARLANE Vernier-assist dual throttle for my ROTAX 912ul. I believe the part # is MCTV0005D048. Does anyone have any experience with this setup? I would appreciate any feedback both positive or negative.
Dutch

[kmach]

I have this exact model/part number. It is a quality setup, I have enjoyed it for 80 hrs now . I use the vernier feature for small adjustments on taxi and cruise.It was a good improvement from my older thicker cable setup that I had to keep the friction lock pretty tight in order to keep settings.

[Av8r3400]

Very nice! I missed out on that one...

[Wheels]

I also have the mcfarlane vernier assembly. I love it.
Follow the recommended instructions for install so that you don't pull the throttle cable out of its sheath, this is a small but fixable nightmare. The vernier assembly uses a set of springs and loose fitted roller bearings and if you pull the throttle handle out during install the bearings and spring become disassembled. Finding them might be a challenge, but there is a Youtube video for the reassembly.
Just don't disassemble it during install like I did and you will be fine.

[Dutch]

Thank you guys.For your feedback. Pulled the trigger this morning. Looking forward to smooth throttle control,

Dutch

[93EG]

Thanks for bringing this up as I have been trying to find a control like this for a while. I have always been lurking but never post but have built and been flying my 4-1200 912S for 14 years. Just finished up about 40 hrs of work on this years inspection. After 14 years many things needed attention.
I made a short test flight yesterday and love that throttle. I was able to set my idle a little lower and use the vernier to keep idle where I wanted it. I had always been pulling on the knob before on final to keep the rpms down.
I also replaced the battery with an Earthx it seems to crank 2x faster and weighs nothing. Also rewired the coils and engine harness so I could use the 6 plus 6 soft start module. I only used 1 and start on it and bring in B after running. My original 6-4-1 modules still working so I changed the connectors on them so I have a spare in my tool kit. If any one needs info on this I have it including where to get the connectors and pins at a great price.

Ed Grasso

[Mcslamma]

Same feelings here, I bought my 1994 model IV-1200 a few years ago, it had the 912 with Bellcrank throttle, could not ever balance consistently, so that it would stay balanced, last winter I changed the engine mount to the slightly beefed up improved one, and did all hoses etc, and put in that Mcfarlane throttle cable, did it and set up as instructed, and love it, works great, smooth, consistant and reliable, worth every penny!!

[herman pahls]

Where are you sourcing the McFarlane throttle.
I have been wishing for this item for years.
Is it a relatively new product or I have been missing out?

Ed
Please share the how to do the 6 x 6 soft start to a 6-4-1 module.
Thanks
Herman

[Dutch]

Herman,I ordered mine from Chief aircraft in Grands Pass OR.
They were cheaper than McFarlane.


Dutch

[93EG]

Herman, I purchased the throttle from McFarlane it came with new carb return springs that seemed to have a little less tension.

I’ll be at my hanger this weekend and take some pics of the connectors and post them with a parts list and wiring diagram next week.

Ed

[kitfox2009]

G`morning Dutch
I just looked on the Chief website and I don`t see the vernier throttle listed,just the standard friction lock ones. Am I missing something?
I have the standard friction lock supplied in the mid 90`s kits and am looking at up-grading.
Cheers
Don

[Dutch]

Don,
They don't have it in their catalog as of yet. But have access to all of MCFARLANE products. call 800-447-3408 & tell them what you need & they will have it shipped directly from MCFARLANE to you. Nice folks & like I said before.
Cheaper than buying it directly from MCFARLANE.
The kit includes all the hardware.Inluding new springs. cable ends, cable locks, & nuts, washers, & even a little hex wrench.

Dutch

[kitfox2009]

Thanks Dutch. I`ll do that
Don

[herman pahls]

Thanks Ed and Dutch
It is great that you guys share this information.
Herman

[Spook712]

How long does the cable have to be for a Modell 4 Speedster?

I sure would lie some information about the soft start module change.

Cheers Tuna

[mcomeaux53]

Chief Aircraft no longer sells throttle cables. I ordered over internet only to have them message me they no longer sell them and failed to remove from catalog....

[Av8r3400]

Aircraft Spruce (http://www.aircraftspruce.com/pages/ap/controls_1mcfarlance/vernierthrottle05-11277-80.php) to the rescue...

[efwd]

I got mine from Kitfox in my firewall forward kit. I wasn't expecting that. I had seen Desertfox1's throttle and new I was going to get that vernier throttle. Contacted the company and everything. I was pleasantly surprised to see that Kitfox supplies it in the 912is package.
Eddie

[mcomeaux53]

How did you set the cable up? Did you use the spring assist on throttles?
I hear some do and some don't use them. Any help? Forgot to mention going in a model 7 with rotax 912...

[Av8r3400]

These cables are designed to pull only, not push. The spring on the carburetor opens the throttle, the cable pulls it closed.

[mcomeaux53]

Thanks for the reply. It's always made sense to me because thats the way rotax sets them up. My last 7 did not utilize the springs and worked great.
I tried the springs on this one and it was like pulling a garage door shut on throttle. I see Mcfarlane provides less pull springs. The one I ordered is a MCTV0005D048 should be good to go.

[jiott]

I bought both the medium and the light McFarlane throttle springs for the 912. I tried both and definitely like the lightest ones the best.

[mcomeaux53]

Not sure what springs they send with unit do you have a part number for the lighter springs? Will I be able to set it up appropriate with springs they provide?

[jiott]

Not sure what you mean by "they" provide. Rotax provided springs are quite heavy. Don't have part numbers, but if you go to the McFarlane website for Rotax 912 parts, you will see that they offer two throttle springs-get the lightest one in my opinion.

[mcomeaux53]

Not sure what you mean by "they" provide. Rotax provided springs are quite heavy. Don't have part numbers, but if you go to the McFarlane website for Rotax 912 parts, you will see that they offer two throttle springs-get the lightest one in my opinion.

I ordered the throttle and was wondering what springs come with the Mcfarlane cable. It actually ships with 2 springs that have lighter pull than the Rotax and conduits. You mentioned even a lighter spring and that is what I was referring to. Thanks for your help here....

[mcomeaux53]

after flying with a push pull cessna type throttle and trying to find the sweet spot. this mcfarlane is the answer. i used the light duty srings to assist and what a breeze.Actually fly and apply friction and still use the veneer feature.
Super nice to find that sweet spot in throttle settings. Higly recommend. I purchased from CPS Chief no longer sells them. A bit more money but I got it.
Any questions ask...

[DesertFox4]

We installed a McFarlane vernier throttle in my 7SS project. It comes with a set of the lighter springs for the Rotax. Seems to be a very high quality item. Needed to trim about 1 foot of the cable shroud to fit. Use caution not to pull the throttle handle out too far before trimming cable shroud. Little parts will fall out of the throttle mechanism. Not hard to put back together as long as no little parts are lost.:rolleyes: Used a dremel with a cut off wheel to very carefully cut through the cable shrouds at the desired lengths and not nick the cables inside.

[fastfred]

Anyone interested in a Vernier throttle cable off a model 7? It has the push button and twist adjustment. I bought a different one . It worked but I was not used to the button. I see McFarlane has a rebuild kit for it available as it is about 14 years old.

[Esser]

If you would have asked me two weeks ago I would have been all over that as I just bought a cable in that time!

[Norm]

Anyone interested in a Vernier throttle cable off a model 7? It has the push button and twist adjustment. I bought a different one . It worked but I was not used to the button. I see McFarlane has a rebuild kit for it available as it is about 14 years old.

Yes I am interested in the Throttle Cable. I'll send you a PM

[Hockeystud87]

I'm about to purchase the McFarland throttle to replace my old 92 kitfox 4 speedster throttle vernier with the threaded rod and small steel ball on the inside.

Running a 912 UL

Is this the correct part? Anything else I need to get for this to work?

https://www.mcfarlaneaviation.com/products/product/MCTV0005D048/

[kmach]

That part number has cable ends.



The cable ends go into the bing 64 carb throttle arm cable bolt attachment.

[Hockeystud87]

That part number has cable ends.



The cable ends go into the bing 64 carb throttle arm cable bolt attachment.

And the 4' cable length is the appropriate size?

[cap01]

if you decide on the mcfarlane , send me a pm and ill give you some tips that may save some headaches . i had a couple of problems but mostly my fault .
great throttle and good customer service, i got mine from mcfarlane. a little getting used to after my old button type throttle .

[Hockeystud87]

if you decide on the mcfarlane , send me a pm and ill give you some tips that may save some headaches . i had a couple of problems but mostly my fault .
great throttle and good customer service, i got mine from mcfarlane. a little getting used to after my old button type throttle .

Currently I have the button but I have not used it a ton. The McFarland uses a friction lock with no button correct?

There should be no issues with throttle creep or anything like that with the McFarland correct?

My current one holds well just getting it initially set is frustrating if I move the throttle with the button.

[cap01]

i used the button all the time on the old throttle and liked it. with the mcfarlane the vernier only works if the push function is locked tight. the friction can also be light enough to allow both push and vernier but there is the risk that during a power reduction with the vernier that the friction will be removed to where the throttle will go to wot on its own. some thing to get used to

[efwd]

Well damn, that would be an interesting discovery should that play out on my first test flight! Thanks for that heads up.

[Hockeystud87]

i used the button all the time on the old throttle and liked it. with the mcfarlane the vernier only works if the push function is locked tight. the friction can also be light enough to allow both push and vernier but there is the risk that during a power reduction with the vernier that the friction will be removed to where the throttle will go to wot on its own. some thing to get used to

Having the throttled locked tight sounds like a scary way to have a throttle setup. I would assume the vernier is really only used in cruise then.

[PaulSS]

there is the risk that during a power reduction with the vernier that the friction will be removed to where the throttle will go to wot on its own.

Is this because of the 'pull' of the carburettor springs? In other words, would this happen with a 912iS, which don't have carburettors?

[efwd]

Yup, 912iS also has a WOT setting with a spring should the cable/connection fail.

[cap01]

i don't want to be misunderstood, i do like the throttle. its a vast improvement over the old one. mcfarlane has some really good customer service people.
they should put a link in the paperwork you get with the throttle to the video on how to reinstall the rollers. even with the precautions they suggest about the rollers , they can come out. its a lot easier to get them back in the second time.

[PaulSS]

Thanks, Eddie, I didn't know the iS had a spring.

[Hockeystud87]

I'll be getting this throttle very soon. I'll be needing to pick a bunch of your brains.

[little rocket]

I have the Mcfarlane throttle 2 cable setup on my 912 and it is smooth and works good ,But I had to go to allot lighter springs on the carbs.I just could not land the plane and work the flapperons at the same time.if you loosen off the friction so that you can control the RPM during landing then you can't let go of the throttle to work the flapperons without the springs pulling it to full throttle.
I went with the lightest springs that would pull the carb to full throttle with the cable Disconnected [which simulates a broken throttle cable].
I found that the Mcfarlane throttle Cables are stiff enough that they can push and pull the throttle without the aid of springs,but I put the light spring on for safety. My carbs stayed balanced with the lighter springs.

[Rodney]

I love my McFarlane cable. It only takes light finger pressure to control the locking mechanism. I got rid of the springs. My carbs stay balanced and I just don't have any problems with the springs gone.

Friend had an SLSA from Kitfox (no McFarlane cable) and it came with no springs on the carbs. So, decided to try it on my airplane.

Love having vernier control on approach to landing. On mine, I can keep light tension on the locking mechanism, so I can either push/pull easily or use the vernier - which ever is most needed at the time.

This setup is so much better than the original.


Regards
Rodney

[GuppyWN]

I have the Mcfarlane throttle 2 cable setup on my 912 and it is smooth and works good ,But I had to go to allot lighter springs on the carbs.I just could not land the plane and work the flapperons at the same time.if you loosen off the friction so that you can control the RPM during landing then you can't let go of the throttle to work the flapperons without the springs pulling it to full throttle.
I went with the lightest springs that would pull the carb to full throttle with the cable Disconnected [which simulates a broken throttle cable].
I found that the Mcfarlane throttle Cables are stiff enough that they can push and pull the throttle without the aid of springs,but I put the light spring on for safety. My carbs stayed balanced with the lighter springs.

Which spring? The light McFarlanes?

[little rocket]

No ,I went with springs that I bought from Lordco automotive store,but last week as the temps started to be cold in the mornings I started having problems with it running rough on startup at idle.Put the carb mate to check carb balance and found that the springs were letting a tiny movement of the throttle arm at idle and I could not get it to balance at idle but balance was perfect above idol all the way to full power.Finally had to put the heavy springs back on to get it back in balance at idle and above.I hate the heavy springs though.

[Wheels]

I would be suspicious that the throttle spring tension has ANYTHING to do with carb balance. Unless you have worn out carburetor linkage, the springs don't contribute to balance other than to seat both carbs on their respective stops.
Your Comment about the colder weather has implications though. When its cold, many pilots close the gap on the spark plugs to the minimum gap. This gives a nice solid spark and helps the "fire" burn immediately on those cold winter days.

Movement on the carburetor arm at idle would indicate loose linkage. could you send a close up pic of the carbs set up? I want to see the cockpit throttle position at idle and the carburetor arms at rest and under tension.
P.M. me if you cant upload the pics and I"ll get you my email.

[Av8r3400]

The springs on a 912 pull the throttles open. Without spring pressure, the cables may slacken causing the carbs to go out of synch.

The braided throttle cables most of us use are designed to pull only. They do not have the rigidity to push, therefore maintaining synchronization without springs is almost impossible.

I have gone to gapping my plugs at .020-.022" all the time. The ignitions are not that strong and my engine seems to run much better at this gap.

[Wheels]

I should have specified, that. Sorry, Av8r300.
I also use the Mcfarlane throttle. Some operators are removing the safety springs for full throttle return to solve the control creep during landing phase.
I did this. I have no problem with pushing the throttle to the stops WOT. I have been doing it for about 350 hours.
I also remove my top cowl at the end of the day. I inspect the engine compartment as part of my pre-flight/post flight. It is a 30 second job at most.

So I don't think I'll have a broken cable in my future but, that said, the springs are for the potential broken linkage in a dual carb engine. Removing them defeats a primary safety device in the unlikely event of a broken carb control.

But controlling the plane in a tight landing situation requires full control as well. I prefer not having to fight my plane to the runway.

The smoothness of the throttle operation without the springs is a remarkable plus for throttle control.

[jrevens]

I should have specified, that. Sorry, Av8r300.
I also use the Mcfarlane throttle. Some operators are removing the safety springs for full throttle return to solve the control creep during landing phase.
I did this. I have no problem with pushing the throttle to the stops WOT. I have been doing it for about 350 hours.
I also remove my top cowl at the end of the day. I inspect the engine compartment as part of my pre-flight/post flight. It is a 30 second job at most.

So I don't think I'll have a broken cable in my future but, that said, the springs are for the potential broken linkage in a dual carb engine. Removing them defeats a primary safety device in the unlikely event of a broken carb control.

But controlling the plane in a tight landing situation requires full control as well. I prefer not having to fight my plane to the runway.

The smoothness of the throttle operation without the springs is a remarkable plus for throttle control.

I sure do agree, Wheels. The length of extended unsheathed cable at full throttle seems to be short enough, and the cable stiff enough, to work just fine for me. I’m not recommending that anyone else run without those springs, but I know that Paul at Stick & Rudder and many others are running without springs, but he does use a larger diameter, stiffer “heavy duty” cable assembly. The possibility of a broken cable seems to be a rather unlikely event. And anyway, how many other aircraft engines use a spring to pull the throttle in the open direction? I think it’s more likely that the real reason is as Av8r3400 said - to put tension on the flexible cables to remove the hysteresis and help maintain accurate synchronization. I’ve found that my synchronization seems to remain really good throughout my throttle range of movement, and I have the standard type cables, not the heavy duty ones. BTW, I use a CarbMate to sync and check them. I’ve thought of perhaps impregnating that short section of exposed cable with something like super glue, to stiffen it if necessary, but it doesn’t seem to be necessary at this time. My engine is very smooth, and I also recently balanced the prop to 0.05 ips. IMHO, having those springs was a real potential safety of flight issue for me... I hated them.

[Av8r3400]

Help me out here. What exactly is a "heavy duty" throttle cable?



I have had conversations with the McFarlane tech folks looking for a better mouse trap on this front and I was told they do not offer any different core options on their cables.


I currently run one of their non-vernier cables and have a ton of drag on it to maintain position. I don't like the system at all. I have run the "lighter" springs only to have the first set fail and break. While they were on, it worked much better than the OEM springs. I have not bought another set (yet).



Playing with my setup, if I remove the springs the carbs will go out of sync and start the engine vibrating and the whole thing snowballs out of management. (Caveat -I have not tried this since going to the large diameter cross tube modification)


I don't know the answer. For me, removing the springs makes things far worse.

[jiott]

I have been using the lightest McFarlane springs for 700 hours now and they haven't broke or worn out. I am surprised yours broke so soon; you should try again. I have found the lightest springs to work quite well, not requiring too much friction to hold the throttle in position. On landing I back off the friction to the point that maybe the throttle might creep a little, but that small creep is not a problem for the short while my hand is working the flaps.

[jrevens]

Help me out here. What exactly is a "heavy duty" throttle cable?...


I'm not sure who supplied them, but they were definitely a larger diameter wire. Perhaps John McBean or Paul Leadabrand could shed some light on that. Maybe a different brand than McFarlane? Also, I wonder if McFarlane could provide solid wire cables (although they told you they didn't offer other core options)... if the routing bends were not too severe that might be an option.



I wonder why mine seems to work so well and yours not, Larry. Perhaps it's the geometry of your cable routing and/or support vs. what I have on my 7SS? I do know of at least 2 other Mod. IVs that are not using the springs. Maybe I won't be able to keep mine like that, but I sure like it much better than those springs, even the lighter McFarlane ones. Operation is very smooth and nice. A vernier throttle would probably solve the "issue" if a builder wanted to go that way.

[HighWing]

I sort of hesitate posting this, but the McFarlane style cable has always seemed a little Iffy to me. Two long cable runs with possibly different lengths and bend angles through the runs and hoping for exactly the same movements at the carburetor has always seemed, in my mind, to be a bit too much to hope for. I installed the fittings on my second Model IV to duplicate the behind the panel splitter that came with my 1993 kit. A single hard wire from the throttle to the wide bell-crank splitter, then the two short cables in a straight run to the carburetors made more sense to me. Also, I was awed by Guy Buchanan's modification - read improvement - of that design when he installed the wide bell-crank on the engine which eliminated any possibility of deviations being inserted by the engine mount dampeners. He had a long single wire cable from the throttle to just forward of the carburetors, then the splitter from that to the short cables back to the throttle arms. Then, probably the greatest motivating factor to go with the 1993 design, was the easy insertion of a counteracting spring between the heavy wire cable behind the panel that totally eliminated the bump to full power effect of the throttle springs. Then add one more thing, the quarter inch (in or out) thumb screw adjustment on the left straight-run carburetor cable that allows for instant adjustment of carb balance while seated with the engine running. Granted, it is a more complex system from the get-go, but in my mind it makes the split cables available seem fraught with too many potentially challenging issues by comparison.

[Wheels]

Yeah, Guy Buchanan had the cool rig, and I wonder if the mangy fox isn't suffering because of the original splitter behind the firewall. The added weight of the hardware would be heavy on a non spring equipped system. I don't have that set up. I took mine off with the 5 lbs of diamond plate the original owner had installed on the rudder pedals for his big feet. :D
Does the Mangy Fox have the original splitter?

[Av8r3400]

The Mangy does not have that horribly designed, Rube-Golberg throttle bell-crank system. My previous IV-1050 did. The first thing I did to that plane was to remove it, as soon as I tried sync-ing the carbs. It was replaced with a McFarlane double-cable.

[Av8r3400]

Lowell, I have great respect for your opinions and fabricating skills, but I don't agree with your assessment of the double cable.



The only way a cable such as this will insert a variation in the two throws is if the core itself stretches. Bending, turning and even coiling will have no effect on the throw movement.


The addition of more joints, springs and linkages all add more variation at every connection and pivot point.

[mr bill]

On my 912ULS, I use the McFarlane vernier double cable and it works well for me. I had replaced the original throttle spring with one from McFarlane and have now replaced that with a torsion type spring from Vans aircraft, instead of the extension (tension) type spring. With the vernier open, the spring will gently and more slowly open the throttle.

[Av8r3400]

Can you expand on the Vans torsion spring?

[jrevens]

Can you expand on the Vans torsion spring?


I think it's a spring that circles around the end of the throttle shaft and "winds up" when the throttle is retarded.

[Av8r3400]

I think it's a spring that circles around the end of the throttle shaft and "winds up" when the throttle is retarded.


Does anyone have a source or web-link for these?

[Guy Buchanan]

I ran out to the airport to get some pictures of my throttle system and what did I find? NO AIRPLANE! Dang.

So I dug up some pictures from the build. It's a short rigid cable vernier push/pull throttle cable going through the firewall to a bellcrank that goes from the cable to the carbs on both sides. The bellcrank supports come off the cylinder head water exit on each side. Each end of the bellcrank is supported by a small sealed bearing. The connections from bellcrank to carb are a combination of threaded female rod and two rod ends. That's so I can adjust each strut's length. The idea was that once sync'd, nothing would move and the carbs would remain sync's forever. (Theoretically, of course.)

[mr bill]

Details of the torsional spring install on the carburetor can be seen in Vans service bulletin 18-03-06.

[Av8r3400]

Here's a link to the Vans SB. Link (https://www.vansaircraft.com/pdf/service_bulletins/sb18-03-06.pdf)

Now for the $68 question, will VANs sell these springs to the general public or do you need an RV-12 serial number to get them?

[GuppyWN]

Kitfox has a lighter spring. I put them on a couple days ago and it is MUCH better. Still have to crank a little friction on the throttle but 1,000,000 times better.

I’ll try this setup for a bit before deciding on the McFarlane throttle or just removing the springs altogether.

[jiott]

I'm pretty sure Van's will sell to a non-RV builder. Since they are here near me, I have bought quite a bit of stuff from them during my build.

[colospace]

My McFarlane throttle came with a set of lighter springs. Does the Vans Service Bulletin imply an issue with the McFarlane supplied springs?

[kmach]

I have been using the McFarlane vernier throttle for 300 + hrs, with the McFarlane supplied lighter springs.

In 2015 when first installed with a new engine install, at the 25 hour engine inspection, I found a broken spring, McFarlane sent me a new set. They have been working since.

My throttle works great, smooth push , pull. l set the friction just so the vernier feature starts to work , never had creap of rpm at idle or on approach with it.

Back in 2015 when I talked with McFarlane , it was mentioned vibration as a big spring breaker, and I was asked if I had an RV12, we discussed the RV12 , seems they had quite a few of their carb springs break. They also said nicking the spring with pliers on install or such was a common reason for the spring to fail.