Thread Tools
This thread is privately moderated by mikejr83, who may elect to delete unwanted replies.
Aug 08, 2019, 08:55 PM
Scale Aircraft = Scale Crators
mikejr83's Avatar
Thread OP

2019 Xplorer X3 Build - Cutting Pushrod Exits

This is probably the hardest step. It's not technically difficult, but cutting holes in you brand new center panel can give you a bit of the hand shakes.

As with any task a little prep before can make the task much easier. Going back to the tools that I listed out in the earlier posts you'll want to have that diamond tipped cutting bit and a conical stone sanding bit along with your Dremel. You'll also need scissors, a felt-tip pen, a hobby knife, some scrap balsa sheeting, the top of a servo case (clear plastic will work), and one of your clevises.

Name: MVIMG_20190808_170442.jpg
Views: 33
Size: 942.9 KB

Cut the top off a case containing a servo. Most servo cases are clear so this generally is a good place to go to get a piece of plastic. Get a ruler and measure 2cm from the edge of the plastic. Place a dot there. Now take the ruler away and place your clevis so that its tip is on the dot. If the other end goes off the plastic that's ok. Make sure the clevis is sitting so that the pin would be parallel to the surface of the plastic, basically in the same position it would be as it was exiting the wing. You'll now take the felt-tip pen and draw a line around the clevis. The outer edge of the line should extend at least 2m, the width of the tip of the pen, from the clevis. Next remove the clevis and color in that whole area.

Name: MVIMG_20190808_170653.jpg
Views: 31
Size: 938.3 KB

You can now position this on your upper wing skin to see how the hole will look in the skin. Don't be too concerned. You haven't cut anything yet.

Now time to cut! The plastic! Cut out the darkened area. You can now pass your clevis through it and be double sure that you have the correct thickness. If it's too small trim a little bit so there is just a couple of mm on either side. If it's too big you can always use another side of the plastic.

Now make a dot in the center of the top. You're going to make a line that runs down the center of the opening and down the plastic. The idea is that your making a line that bisects the width of the clevis and will use it to center the "hole" on the wing skin where the clevis will exit and connect to the control horn.

Name: MVIMG_20190808_171125.jpg
Views: 14
Size: 647.0 KB
Description: Name: MVIMG_20190808_171133.jpg
Views: 16
Size: 687.7 KB

Notice how I have the hole in the plastic on the flight surface and not on the control surface. The line you drew on the painters tape that lined up with the control horn should now provide a great way to center the opening for the clevis with how it will exit the wing! Take your pen and color that section in. You can round the top, the edge of the hole towards the leading edge, so that it looks a little cleaner.

Name: MVIMG_20190808_171315.jpg
Views: 18
Size: 943.2 KB

Now grab some scrap balsa. I've used 1/16" thick. It doesn't really matter. It could be ply. What you're going to do is to make a jig to hold the control surface while you work on the wing. I cut two rectangles 10cm x 3cm and then another rectangle to cut up smaller to make the braces.

Name: MVIMG_20190808_172423.jpg
Views: 17
Size: 927.9 KB

You can now take the two larger pieces and set them at a right angle and use the smaller squares to brace it all up. This doesn't have to be pretty. Again, it's just making a right angle piece so you can safely secure the control surface. Get two small pieces of scrap and two small clamps. Put a piece of scrap on the top skin and the jig on the bottom. Use some small clamps to hold it in place.

Name: MVIMG_20190808_173119.jpg
Views: 19
Size: 808.0 KB

Now you're ready to start cutting!

I'm serious this time. I didn't have a camera person to help me take pictures of this step so I'm going to describe it. With the diamond bit you can trace around the skin to make the hole. Using this method works well but the biggest hurdle will be cutting the sub-spar. I find it best to cut the trailing edge to the sub-spar, stop and move over the skin to the other end and then work back to the sub-spar. From there you'll just gradually run the diamond bit through the sub-spar. I then tilt the wing up so that I can work in from the trailing edge. Take the sub-spar all the way down. You'll get to a white epoxy joiner between the bottom skin and the bottom edge of the sub-spar. This is a little thicker than you'll initially think. You'll want to grind it flush with the skin. You can switch to the conical stone sanding bit here and it tends to work better on the epoxy.

Finally finish up with some hand files to clean up everything. I leave just a shred of the pen mark when cutting and then use files to clean it that last little bit.

Name: MVIMG_20190808_174112.jpg
Views: 16
Size: 772.5 KB

It might take a little bit of deep breathing to get started on this part but if you take the time to prep with the template made from the plastic and line up the markings things should go just well. One word of caution. You may be tempted to go with a cutting wheel. I find these too big and aggressive for the small area. It's too hard to get right and you'll find yourself overshooting the length due to its arc. It's also pretty easy to go too deep too fast with them. Stick to the diamond cutting bit that's fairly thin with the sharp point and you'll do just fine!

Next we'll do servo installation!
Sign up now
to remove ads between posts

Quick Reply
Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Tiger Rag build - now for CAP 2019 FlyingTyger Vintage & Old-Timer Designs 27 Apr 07, 2016 07:07 AM
Discussion Molded Supra pushrod exits old dodger Thermal 16 Feb 03, 2008 09:45 AM
Gallery 11. SC Pushrod Exit Jack Stephens Your Plane Photos 0 Jun 19, 2005 11:32 AM