Control Rigging

[Chris in Milwaukee]

So, since I've had the Maule, it's flown with a bit of a lean to the right and a half bubble off to the left. Having resolved to cure this problem, I took the bird to the shop today, along with the service manual, and turned it over to the mechanics for an inspection. The maintenance director turned it over to an experienced guy, and he set it up just as the instructions in the book dictated, and found some cool stuff.

* Dihedral was good on both sides
* Washout was .2" on the left, .5" on the right
* Aileron travel normal
* Left aileron drooping 3/8"
* Right aileron drooping 1/8" (ailerons should be 0 to -1/4")
* Aileron cable tension about 5-8 lbs low, controls a little sloppy (no yoke deflection with minor control surface movement)
* Flap travel normal
* Left flap drooping 1/8-1/4"
* Right flap normal position
* Rudder travel normal, cable tension normal
* Rudder position normal, rudder springs normal
* Elevator travel normal, cable tension normal

With that in mind, if the left side controls are drooping, then that explains my heavy right wing and being a half bubble off to the left (corrected with right rudder).

Mechanic is going to set cable tension and surface position, and we'll go for a ride and see if that straightens things up. Hoping that helps out before doing bigger stuff, like disconnecting wing struts and such.

Heck, with luck, might even get another MPH or so out of the deal!

[gbarrier]

Lean to the right might have been the more washout on that side. Drooping ailerons only mean that the yoke won't sit straight when the ailerons are aligned as they streamline in the wind, at least if they were manufactured straight.

Be sure the flaps are exactly the same angle. There are a lot of them hanging out there. With the wash the same it should trim up pretty straight with the ball near center. Hate to but if it doesn't you might need to tweek a flap a tiny bit.

[Chris in Milwaukee]

I'm thinking that, too, but will do it as a last resort. We'll see after the next flight, I reckon. Fingers crossed. Probably still have to adjust it.

[DeltaRomeo]

Make the washout the same on both sides; otherwise it will cause an unwanted stall effect...

[Chris in Milwaukee]

Two folks saying to address the washout is enough for me. Just called the shop and asked them to fix that as well.

Thanks for keeping me (and the ship) straight!

[Andy Young]

Yu may still need sme differential wash to get it to fly right. Every airplane is different, and none of them are perfect. But you need to start with everything at spec., THEN adjust as needed to get the desired effect. So yes, adjust that wash so they are the same, then go fly.

[crbnunit]

Good info. I need to check my rigging as well.

[Chris in Milwaukee]

Make the washout the same on both sides; otherwise it will cause an unwanted stall effect...

It does tend to drop the right wing first on stall, so probably another clue.

I did also notice when I was doing a quick geometry measurement that tailpost to wingtip trailing edge corner was about 3/4" off between the left and right sides. But that may not be a trustworthy measurement due to variations in fiberglass parts installation. The measurement would be more accurate if I took the wingtip off.

Not that I could square the structure up, anyway, without removing the fabric and heating longeron tubes to strategically shrink the steel and bring things back into perfect alignment. That's a rebuild/restore operation.

"Perfection is the enemy of completion."

[Andy Young]

And you're talking a level of perfection that was likely not achieved at the factory. Not being disparaging here; just the reality with most reasonably-priced light aircraft.

[Chris in Milwaukee]

And you're talking a level of perfection that was likely not achieved at the factory. Not being disparaging here; just the reality with most reasonably-priced light aircraft.

Oh sure, I get it. No concerns at all. Just an observation. She'll fly like a champion.

I'm building a Bearhawk and expect the same to be true. Handmade aircraft will always vary a little bit.

[DeltaRomeo]

There is a built in cant to the right in the vertical fin to account for the various forces in flight. All Maules have it. Maule mounts the engine square to the engine mount and does not have a thrust angle (usually slightly down and to the right in most aircraft).

[bobguhr]

Speaking of rigging, does anyone know of a mechanic with Maule Rigging experience in the North East? Any leads would be much appreciated.

[Chris in Milwaukee]

Flew the MX for the first time since it was re-rigged. Heck of a difference! It does barely tend to wander off to the right when hands off, still. But one finger on the yoke and it doesn't move. That's a lot better than it was before when I had to constantly hold the yoke with a fair amount of pressure.

It's still a half ball off under normal conditions, and I have to keep right rudder on to keep it straight. If I have the rudder trim pulled all the way out, it'll stay mostly on center.

I think I'll fly it for a bit and try to get a feel for what it needs. Perhaps, as suggested by others in the archives, I can adjust the tab on the rudder so it's located off to the right a bit at neutral aileron.

I didn't check for speed differences since I was mainly trying to feel for level. But when I was coming back toward the airport, I did notice about 105 MPH at 2200-2300 RPM.

[Andy Young]

Check that the tension is even on the rudder springs in the fuselage (behind the rear bulkhead in the cargo compartment). The clamp that holds the end of one of them is on an angled tube; the clamp can slide down the tube, relieving tension on the spring on the side, causing the rudder to deflect.

[Andy Young]

Check that the tension is even on the rudder springs in the fuselage (behind the rear bulkhead in the cargo compartment). The clamp that holds the end of one of them is on an angled tube; the clamp can slide down the tube, relieving tension on the spring on the side, causing the rudder to deflect.