Vernier Mixture and Throttle

sj · Post by sj » Mon Sep 16, 2002 12:59 pm

Folks,

Sorry for the 170 newbie questions, but I have many:

Is there an STC for replacing the throttle with a vernier throttle? I like the big 'ol knob, but vernier would be nice.

Same question on the mixture, which is funky with that little metal gadget to hold it in (no doubt somebody thinks it is preciously cute and functional).

THANKS!

sj

Roesbery · Post by **Roesbery** » Mon Sep 16, 2002 3:10 pm

I took a vernier throttle control out and put in a standard throttle control. Because when I want to pull it to idle,I don't want to be pushing at the same time I'm pulling. Had a engine start at full power one time and might near pulled the panel apart pulling on the vernier control. My 2 cents.

sj · Post by sj » Mon Sep 16, 2002 3:11 pm

Hmmm Normally they have a button on the end to push in in order to do just that very quickly...

Post by **GAHorn** » Mon Sep 16, 2002 5:07 pm

sj, re-read Roosberry's post.
This engine's carb is so crude there's little to be gained by vernier controls. Verniers are designed for fuel injected, constant speed, and turbo-equipped engines that can effectively utilize minute adjustments (popularized by that snob-group who even refer to themselves as a "society"). Even so, most vernier throttles are only to "go along" with the vernier prop/mixture controls on those fuel-injected engines. I find vernier throttles are troublesome. You have to fiddle with that push-button anytime you want to do something at other than a snail's pace, and even on BIG Turbo-Compound-Super-charged engines that went all the way up to 75 inches of MP, they were hated and never used by the pros.
(I never liked the "twist" and thought it was stupid.)

N3243A · Post by **N3243A** » Mon Sep 16, 2002 6:33 pm

I got tired of the mickey mouse standard mixture knob too. It's tough to adjust precisely especially in turbulence so decided to get a vernier model. So, during an annual 2 years ago, my A&P installed an Aircraft Spruce generic model vernier mixture control. We ordered one extra long, then cut it to exact length for the install. He didn't think it was any big deal, no 337, no field approval, just a log book entry that read "installed vernier mixture control." Said he'd done it to many airplanes.

SJ, I agree with the others on NOT having a vernier throttle however. And I am even more surprised to hear a super cub pilot wanting one. I don't think you will ever see a bush plane in Alaska with a vernier throttle. I guess the reasoning being is that if you need to apply or retard the throttle NOW, you don't need the complications of the little release push button on the end. Do you have one on your super cub?

Bruce Christie, N3243A

sj · Post by sj » Mon Sep 16, 2002 10:56 pm

No, the supercub has the throttle in the right place - in the left hand so it is not an issue.

In fact the only thing I don't like about the 170 is that it is a yoke instead of a stick, but I knew that going into it. I may ask a lot of stupid questions, but I won't be asking about an stc for that conversion, don't worry...

I'll eventually just fly the 170 from the right like I do most other side by side planes (not twins or throwover Bo's), and then I will be more comfortable with it.

My AI at the time would not sign off a vernier mixture on the cub, he asked the FSDO and they considered it 337 material. Your local results will vary...

I appreciate your comments!

sj

Post by **GAHorn** » Tue Sep 17, 2002 4:17 am

There is a very nice engine control cable offered by Univair 888/433-5433 that works very well for mixture, getting rid of the metal lock-tab. It uses instead, a type of "ratchet" built into it that positively holds the cable in the position last set. I have one and like it very much. It is their A-740 model. Comes in 60 and 72 inch lengths which may be shortened by cutting.

sj · Post by sj » Tue Sep 17, 2002 12:17 pm

Thanks! That is the kind of advice I am looking for.

sj

N1478D · Post by **N1478D** » Tue Sep 17, 2002 1:51 pm

gahorn wrote:There is a very nice engine control cable offered by Univair 888/433-5433 that works very well for mixture, getting rid of the metal lock-tab. It uses instead, a type of "ratchet" built into it that positively holds the cable in the position last set. I have one and like it very much. It is their A-740 model. Comes in 60 and 72 inch lengths which may be shortened by cutting.

That must be what is in mine, I do not have a metal tab. As I pull/push the mixture it ratchets to that position very nicely. I think you would like it.

DHeal · Post by **DHeal** » Tue Sep 17, 2002 4:08 pm

We have vernier throttle, mixture, and prop controls in our company F33A. I've gotten used to them and like the way you can fine-tune the settings. Of course, "fine-tuning" a C-145-2/O-300 is a bit of an oxymoron... Also, some folks still don't seem to be able to get the hang of a vernier throttle - see this recent NTSB report: <http://www.ntsb.gov/NTSB/brief.asp?ev_i ... 1614&key=1>
----Dave

Watkinsnv · Post by **Watkinsnv** » Thu Sep 19, 2002 5:20 am

Since I'm putting a Lyc with C/S prop the STC came with a vernier prop control cable. I don't think its a good idea to mix the different control cables, so I am putting in vernier control cables on the mixture, prop and throttle with the 337 for the Lyc STC. Or If the FAA wants another 337 with the mixture, and throttle vernier contorls, key start switch and shower of sparks and on and on. Lance

Jeff Matthews · Post by **Jeff Matthews** » Wed Dec 11, 2002 12:57 am

I used to fly 180's for the forestry people--we had several of varying vintages, and the engine controls were not always standard. I hopped into one of them, took off, pulled the manifold pressure back some, and started twisting back on the prop vernier. After several twists, no change in RPM. After a couple more twists the engine ran rough, so I turned it back in, moved over one knob, and twisted back to climb RPM.

I prefer engine controls that feel different from one another. Nice smooth slidey feel for carb heat, rattccch for the mixture, and twisty for the prop. But it doesn't really make any difference now, since I don't have a fleet.

I got fond of the mixture controls on 172's of the mid '70's (and probably later, I haven't checked). They had a spring and ball detent ratchet that was smoother and lasted longer than the one I got from Spruce.

LBPilot82 · Post by **LBPilot82** » Sat Dec 12, 2009 1:13 am

I'd like to bring back this old post, if nothing else, just to pop the lid off this can of worms

I really want to get away from the spring tab on my mixture control. I don't want vernier so I would like to use the A-740 (ratchet style) cable George mentioned. Problem is, the one that Spruce offers (and I'm assuming the one from Univair as well) is NOT FAA PMA'd. Because of this, my mechanic won't sign it off. He did however suggest using a similar style cable from a 172 and cutting off and making a new knob (I want to keep it looking original). This would satisfy me as well as him by using a PMA'd part and installing it on my plane as a minor alteration.

So then I go looking at these in the Spruce catalog and about lost my lunch after seeing the price.

Any thoughts or recommendations????

Brad Brady · Post by **Brad Brady** » Sat Dec 12, 2009 1:45 am

LBPilot82 wrote:I'd like to bring back this old post, if nothing else, just to pop the lid off this can of worms

I really want to get away from the spring tab on my mixture control. I don't want vernier so I would like to use the A-740 (ratchet style) cable George mentioned. Problem is, the one that Spruce offers (and I'm assuming the one from Univair as well) is NOT FAA PMA'd. Because of this, my mechanic won't sign it off. He did however suggest using a similar style cable from a 172 and cutting off and making a new knob (I want to keep it looking original). This would satisfy me as well as him by using a PMA'd part and installing it on my plane as a minor alteration.

So then I go looking at these in the Spruce catalog and about lost my lunch after seeing the price. Any thoughts or recommendations????

Well, I didn't change any cable or anything else on my 172. But the knob broke off and I replaced with a John Deere Knob. the old knob was just red, this one says more. I think!

PC110016.JPG

LBPilot82 · Post by **LBPilot82** » Sat Dec 12, 2009 4:02 am

Thanks for the pic Brad. Is your mixture just a friction lock push/pull? If so, what year is your 172? Better yet, got a p/n???????

Thanks again.

The International Cessna^® 170 Association