Experience with Vans standard throttle/mixture cables?

Hello all,

I am curious to see what people?s experience has been with the standard push-pull throttle and mixture cables that Vans sells and see if there are any alternatives out there.

I recently converted an RV-6A from quadrant to the standard push pull. I had some issues doing this. Mainly once I got the correct length of cable, the throws on both didn?t seem to be quite adequate. For the throttle I had to use the very top hole of the throttle arm to be able to get full deflection. For the mixture, I was limited to one hole and it doesn?t quite give me full deflection of the mixture arm and has much less throw than the throttle (which is probably normal but still not enough). It seems that adding a little more throw would cover a lot more applications and not have this issue. Has anyone else experienced this?

Finally, once I got them all in and fired up the motor, the throttle has to be held (or locked) at idle. If the friction is taken off, the throttle will creep quickly to about 30% forward which is frustrating and requires diligent locking. The friction lock on the standard Vans throttle is not linear enough to hold it while still allowing for manual movement. It?s either locked or drifts forward with even the slightest amount of ?unlock?.

Just seeing if this is common, some workarounds, and if there are better cables out there that maybe have smoother friction locking action vice all or nothing.

Thanks all!

Charles

cables

I used all stock Van's cables. I've been flying only 10 hours on my RV-7A and here are my findings.

1. The throttle is either too loose or too tight. If I tighten the lock wheel it gets too tight to NOT easily moved for landing. So for landing I loosen it completely. But it is very nice in cruise to lock it and know it will stay where I put it. Also on climb I have noticed the throttle will pull out o its own if lock wheel is loose. So I'm learning to keep my hand on it. I even loop two fingers behind the lock wheel which is helpful at both holding the cable in and feeling how far in or out it is. I'm getting better at adjusting the lock wheel with a finger during climb and descent.

2. The Prop cable works great. I pretty mush just turn it. Only time I pull / push is on run up before take off. I don't see a need to do fast or quick prop changes so turning works fine.

3. The mixture cable seemed to be working correctly, but on last couple of flights I'm not sure I'm getting full rich. I need to examine my setup and see if I have it rigged correctly. I mostly push or pull it, rather than turn. But I have noticed there is about an 1/8 inch when fully rich that I need to turn in. That's what I need to double check.

The other cables for heater and aux air work fine.

I am basically satisfied and like the Vans cables. I transitioned from a Piper Cherokee that had the quadrant.

I hope this is useful.

Have been using the stock Vans cables for 7 years and 500 hours. Regarding your second concern, absolutely no complaints. I just set the friction control so that it's clearly providing some resistance to the knob. Enough resistance to keep the knob from moving in or out, but not so much that I can't easily override it. That's how mine is set pretty much 100% of the time and in all flight phases. Again, no issues, no complaints. Maybe you have some from a different batch that don't work that way. Having said that, the exact same approach was used with no problems when I flew Cessnas with similar controls.
Hope this helps, even if it rules out part of your issues.

Yeah, unfortunately the friction is more like sgylnn is talking about where it?s almost all or nothing. If the throttle is let go at idle on the ground it?ll quickly travel to about 1/3 throttle up, way too much for ground taxi ops. I?m trying to think of a way to incorporate a little more friction into the system, possibly having the cables travel through a short piece of hose that?s slightly clamped to it. I?ll have to play around with it. As it stand, the throttle creep is not acceptable.

alpinelakespilot2000 said:

Have been using the stock Vans cables for 7 years and 500 hours. Regarding your second concern, absolutely no complaints. I just set the friction control so that it's clearly providing some resistance to the knob. Enough resistance to keep the knob from moving in or out, but not so much that I can't easily override it. That's how mine is set pretty much 100% of the time and in all flight phases. Again, no issues, no complaints. Maybe you have some from a different batch that don't work that way. Having said that, the exact same approach was used with no problems when I flew Cessnas with similar controls.
Hope this helps, even if it rules out part of your issues.

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Make sure your cable routing allows a straight exit from the body and that you don?t have any short/severe bends or loops anywhere along the run.

It is also possible that you simply have a bad cable assembly.

I agree that the throttle is either too loose or tight. Anyone come up with a solution for this? I was thinking of adding a spring between the bushing and the tightening base inside the cable

I would try a drop of lubricant on the pilot side of the throttle cable shaft. Then cycle the throttle a few times and play with the friction setting. (it took me a while to come up with a way of saying that without using "work the shaft"..haha)

Ha! If we were in the Air Force we could just use "so to speak" on this thread.

I was thinking a spring as well. It wouldn't be so bad if the throttle didn't creep up so rapidly. It's nothing I can't handle but this is on my girlfriend's plane and she's having a much harder time simo-manipulating throttle and lock and having to apply force to keep it at idle.

WingsOnWheels said:

I would try a drop of lubricant on the pilot side of the throttle cable shaft. Then cycle the throttle a few times and play with the friction setting. (it took me a while to come up with a way of saying that without using "work the shaft"..haha)

Click to expand...

WingnutWick said:

Yeah, unfortunately the friction is more like sgylnn is talking about where it?s almost all or nothing. If the throttle is let go at idle on the ground it?ll quickly travel to about 1/3 throttle up, way too much for ground taxi ops.

Click to expand...

My throttle control was like this when new as well, however, by the time I had 20-30 hours on it flying with the friction set all the time and moving the throttle anyway, it really "broke in" and now the friction can be set to any desired point pretty easily with good repeatability. Maybe they are still like this i.e. need to be broken in a bit?

I just gave up.

Originally I used a standard throttle quadrant but found that a single friction control for three levers was unsatisfactory. I did a lot of formation work and wanted the throttle to be easily moved but then the prop or mixture would creep. The solution was to remove the prop and mixture controls from the quadrant. This is the setup for most aerobatic airplanes and works for me.

My Mastercraft ski boat throttle is set up to always have tension on it, for precise control of boat speed during slalom course runs, similar concept to the spring on the stick the Blue Angels fly with. Since we aren't competitive and 95% of our use of the boat is away from a slalom course, a crude but effective friction lock was to put a wire rope clamp around the throttle cable:

My experience with the cables supplied by Vans for the -6 or -7 is that they are just long enough and are shy on total travel. I ordered same type of cables to my length and travel requirements.