Aileron control rod/bell crank rigging

[Skippydiesel]

Have just come from trying to rig my aileron control rods/bell crank angle. Phew! no easy task its very "tight" inside the wing.

I am hoping that some kind person (s) who has been down this particular track, can advise me of the easiest way to achieve the 25 degree bell crank angle, while connecting the control rod from it to the aileron (which must be held in the "neutral" position).

I should mention - the first builder of this aircraft has fitted ball joints to both ends of all control rods (Sonex plans show ball joint on one end only).

Of particular interest is how to hold the bell crank, without moving, at the desired 25 degree position. If I can achieve this, most of the other dimensions/requirements should not be so hard to achieve.

[Bryan Cotton]

If they made one rod end left hand threads, then it's easy to adjust. You twist the rod to lengthen or shorten.

[Skippydiesel]

If they made one rod end left hand threads, then it's easy to adjust. You twist the rod to lengthen or shorten.

"IF" only Bryan. Twisting the rod results in equal screw in/out. I have to remove one end to make adjustments (I wish the first builder had followed the Sonex plan).

Still got to find a way of measuring/clamping the bell crank to 25 degrees. Might have to make up a 25 degree spacer - but how to "fix" bell crank while making the adjustments???

While on the subject of clamping - as an interim measure (before fine tuning, I assume that clamping the aileron to the flap, will deliver neutral aileron position - is this correct?

[Skippydiesel]

FYI - Set your outer (short) control rod length to 480mm center to center.

Connect the rod to the aileron

Clamp your aileron to your flap - use a strait edge to check your trailing edges are level (this assumes the resulting position is aileron neutral, as per Sonex instructions).

Connect to bell crank.

Measure angle (see Sonex plans for detail) as best you can - should be fairly close to 25 degrees. Any adjustment will be small.

Remove clamp.

If all OK, tighten lock nut (s) while securely holding ball end in correct alignment.

(Clamp - I made mine from two large "fender" washers, wrapped in electricians insulating tape. Long narrow bolt, I used a 4mm, passed through both washers secured with wing nut. Take care not to screw i too tight, just enough to hold both flap & aileron in alignment)

[DCASonex]

If they made one rod end left hand threads, then it's easy to adjust. You twist the rod to lengthen or shorten.

If anyone does build it with right and left hand threads, like an extra long turnbuckle, be sure to safety wire those ends. That "easy" adjustment is not something you want happening in flight.

David A

[Bryan Cotton]

If they made one rod end left hand threads, then it's easy to adjust. You twist the rod to lengthen or shorten.

If anyone does build it with right and left hand threads, like an extra long turnbuckle, be sure to safety wire those ends. That "easy" adjustment is not something you want happening in flight.

David A

Very true. Sikorsky helicopters use this extensively and they are safetied.

Still important to safety when only one end adjusts.

The OPs issue still seems easy. Fix one end, adjust the other. When adjusted, if you don't like one end, turn both sides the same number of turns until you are happy.

[Skippydiesel]

If they made one rod end left hand threads, then it's easy to adjust. You twist the rod to lengthen or shorten.

If anyone does build it with right and left hand threads, like an extra long turnbuckle, be sure to safety wire those ends. That "easy" adjustment is not something you want happening in flight.

David A

This is not a turnbuckle.

Please excuse my ignorance but how do you safety wire a ball end joint ??

[peter anson]

It is possible to get nuts that have a lock wire hole and I have seen rod ends that are drilled for lock wiring but it's a sure bet that your aircraft doesn't have that type. All my control rods are fitted with right hand rod ends at both ends and just locked with a lock nut. It's possible to check many of them when doing the daily pre-flight and for anything to shift, two lock nuts must come loose. I don't recall it being difficult to rig. Clamp the aileron in place; set the bell crank at the correct angle and adjust the control rod ends until the holes line up.

Peter

[Skippydiesel]

It is possible to get nuts that have a lock wire hole and I have seen rod ends that are drilled for lock wiring but it's a sure bet that your aircraft doesn't have that type. All my control rods are fitted with right hand rod ends at both ends and just locked with a lock nut. It's possible to check many of them when doing the daily pre-flight and for anything to shift, two lock nuts must come loose. I don't recall it being difficult to rig. Clamp the aileron in place; set the bell crank at the correct angle and adjust the control rod ends until the holes line up.

Peter

The rod (ball joints) ends have a "witness" hole drilled through - this is to make sure your threaded (male) end goes in at least as far as the witness hole. I suppose I could drill another two holes and purchase lock nuts with a hole in but Sonex dont call for it and I am inclined to go with your approach.

On my Sonex its impossible to tighten the lock nuts in situ - the rod must be adjusted as best I can, very carefully removed, placed in a padded vice, first lock nut tightened, second carefully tightened, so ball end at 90 degrees to the first.- replaced and bell crank angle checked. I did this at least 6 times to get the angles correct. As mentioned above I measured the first assembly and used that measurement to do the second set up in just about 3 repeats.

The difficulty is getting the 25 degrees -Its hard to measure in such a confined space and once measured, easy to knock out of position. I have done it now but to double check will get my Son to make up a 25 degree spacer in his 3D printer.

Not having flown a Sonex I suspect that the bell crank angle is key to effective aileron differential movement and when turning (using just aileron), minimal/nil initial yaw.

[peter anson]

You don't necessarily need to tighten the lock nuts with the control rod in situ. I would suggest adjusting it to the correct length and then removing the rod to tighten the interior lock nut. If you need to make any further minor adjustments you can do it on the external rod end. As far as preventing the bell crank from moving from its 25° position, it should be possible to clamp the far end of the long push rod against the spar using a G clamp and some suitable padding.

Peter