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Permalink Reply by Alan Lampson on September 6, 2024 at 1:16am

In the STOL CH 750 forum, search for flaperon adjustment.  Currently, the 5th spot down shows "after many days..." referring to "Sequence to a successful flaperon adjustment".  I have not tried it yet, but have printed it out for when I have to do this.  This sequence was worked out with the former Zenith engineer Caleb.  I hope it helps you.

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Permalink Reply by Fred Wellman on September 6, 2024 at 2:19am

I can't get onto the STOL 750 forum, and Roger is at an airshow for a week.  So unless someone can send me a link or the " password" to that forum, I am stuck. Very frustrating. Why each forum has its own "password" is a mystery to me. Can you copy and paste the sequence so that we have it on this forum?  Thanks.

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Permalink Reply by John Austin on September 6, 2024 at 10:39am

You can join as many forums as you wish - you're not limited to the Cruzer Forum.

This post explains how to join a forum.

John

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Permalink Reply by Fred Wellman on September 6, 2024 at 12:49pm

Thanks.  I always got the reply “You must be a member to participate and view”.  I didn’t notice the “Join” button.  I’m in now.

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Permalink Reply by John Austin on September 6, 2024 at 1:21pm

You're welcome!  ... and remember - no limit on how many forums you may join.  I learn something on every one of them!

John

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Permalink Reply by Kurt Van Hulzen on September 6, 2024 at 8:03am

Here is a copy/paste of what Alan refers to:

Sequence to a successful flaperon adjustment

• Posted by Blaine Schwartz on October 30, 2014 at 6:48pm in STOL CH 750
• Back to STOL CH 750 Discussions

After many days of making adjustments to the flaps and chasing the measurements, I worked with Caleb, who patiently guided me through the process. I was unable to find enough information in any of the documents we builders have available to us. I hope this step by step process helps those embarking on this adjustment.

1. Level the plane on both axis. Use the longerons and spar carry through on the cabin frame.

2. Run the flap motor up and down, measuring the angle on the short tube that is welded to the mixer tube and attaches to the bell cranks. The angles up and down should be the same (+ or- from level).

3. Run the flap motor all the way up. Adjust the horizontal control rod ends that attach to the torque tube and bell cranks to get the top of the bell cranks level.

4. Adjust the vertical rod ends that attach to the bell cranks on the bottom and flaps on the top to achieve the neutral position for both flaperons (as measured per drawing 75-ZA-7 near the outer edge of each flaperon).

5. Once neutral has been achieved, measure the angles for each flaperon and record the angle. This will be your reference point to measure deflection from.

6. Check the deflection for both right and left flaperons by moving stick from side to side and recording the resulting angles for both sides and for both up and down measurements (there will be four measurements).

7. Calculate the angles from neutral (example: if your neutral position is -3 degrees and your right flaperon measures – 16 degrees when you bank left, you are at -13 degrees (difference between -3 and -16 degrees). Do this for all four measurements.

8. Make adjustments to the horizontal control rod ends to achieve the + or – 13 degrees as shown on drawing 75-ZA-7. Write down what changes you made (i.e.: 1 turn in on right control rod) to help you determine if you are headed in the right direction. Make one adjustment at a time.

9. The previous steps all take place before you install the stops (PN 75-Z1-12). Once you have completed step 8, you should have equal movement of the flapeones up and down (+ or – 13 degrees from neutral). You should be able to move the stick beyond the 13 degrees, but when you install the stops, movement will be limited to the + or – 13 degrees. This is easier done with two people; one moving the stick and the other holding a level at the outer edge of the flaperon. Estimate where the stop should be located relative to the two AN3 bolts it will be attached to and drill the holes in the stops. Be sure to leave a little bit extra material on the inboard end that meets the tab on the torque tube allowing you to remove a little more material after you have installed the stops and get a better idea what angle the flaperon now stops at. This is an iterative process.

10. Bring back to neutral position and run the flap motor all the way down and check the angles on both flaperons and adjust the flap motor as needed. Remember to calculate your angles from the neutral position.

11. You will likely need to readjust your neutral positions later by adjusting the vertical rods.

12. Note: every adjustment you make has an impact on the other angles so keep checking and recording all measurements.

13. Have patienceJ

14. Celebrate with your favorite beverage after successfully completing the adjustments.

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Permalink Reply by Fred Wellman on September 6, 2024 at 7:21pm

If anyone is interested…

I had been dreading rigging the Flaperons because I read on the Zenith forum that people spent days getting them properly rigged. It seemed like it should be a simple enough job, but the forum had me worried. I began rigging the ailerons and within an hour or two I had neutral set, and the 13 degrees up and down set. When I checked the flap deflection, they went to 22 degrees, the plans called for a maximum of 15 degrees. I spent the next few days trying every combination of rod/bellcrank adjustment possible, always ending up with 22 degree of flaps. At that point I decided to think logically about the problem.

The Flaperons are controlled by rods connected to bellcranks. As long as the bellcranks are set at the same angle (roughly horizontal) and the rods are the same length at neutral, then the only thing regulating the aileron up and down movement are the aileron stops. Once those are set, the only thing left to do is set the flap deflection. The only thing controlling the flap deflection is the flap motor connected to the mixing arm. The more the flap motor moves the mixer, the more flap deflection you get. So it stands to reason that if I get 22 degrees then the flap motor is extending too far.
No one on the forum seemed to know of any adjustment inside the flap motor to shorten the stroke of the flap motor.

I guessed there had to be limit switches inside if the motor, so I decided to take the motor apart. Before taking it apart I measured the stroke at 22 degrees flaps (165 mm), 15 degrees flaps (108 mm) and zero degrees flaps (64 mm).
Then I took apart the flap motor. There is a micro switch limiting the stroke out, and a micro switch limiting the stroke in. I hooked up a battery and ran the flap motor to the 108 mm (115 degree) position. I moved the micro switch to that position ( easier said than done) and put the motor back together. I mounted the motor in the plane, tested it, and viola! 15 degree of flaps. Had I known this from the beginning I could have saved 3 days of frustration. Silly me thinking that the factory would have the flap motor set correctly.

So, if you are able to get everything properly set ( neutral, 13 degree up/down aileron deflection) but can’t get the flap deflection right, check the stroke of your flap motor.  Below is a photo of the limit switches in the flap motor.  The are held in place by a slot in the housing and a bump in the bottom slot. If you move them you will need to Dremel the bottom of the wafer to go between the bumps.  I moved the forward one back to where they were nearly touching each other.

Attachments:

• 20240906_125058.jpeg, 968 KB

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Permalink Reply by Richard Pierce on September 8, 2024 at 6:26am

Thanks for the information. I had the same issue with the flaperons on my Cruzer except they went to 18 degrees. I found the same style motor assembly that is used on a handicapped chair lift and disassembled it to see if the the limit switches were adjustable but they weren't so I assumed the one used for the Cruzer was the same. I ended up mounting a micro switch that is activated by the flaperon motor to an LED on the instrument panel next to the flap switch and set it to go on at 14 degrees. I may have look into removing the flap motor and resetting the limit switch once the wings are reinstalled and the flaperons are hooked back up.

Attachments:

• IMG_4418.jpeg, 3.2 MB

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Permalink Reply by Fred Wellman on September 9, 2024 at 6:53pm

I was going nuts trying to get the flap deflection to 15 degrees before I realized that it is the stroke of the flap motor that determines the flap deflection.  Make sure you measure the stroke at 15 degrees so that you can set the switch to stop the motor at that length.  Not difficult, just take your time with the placement and dremeling the bottom corners of the wafers to fit between the bumps.  Once you put it back together it will be locked in place.  You could probably add a drop of superglue, but I did not.

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Permalink Reply by charlie rosenzweig 7 hours ago

WOW, Never heard of this.    Wish I had know about this before.    I too have a bit more travel on my flaps than I would like, but the thought of removing that motor is a bit more than frustrating.  But THANK YOU for sharing.  I would have moved those limit switches outisde of the housing and placed them in a way to connect with the swing arm so they could be adjusted and repaired if needed..   

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