RCU Forums - View Single Post - Top Flite B-25 - Wingspan Models Add-ons Build Thread
Old 07-10-2008, 11:30 AM
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RCKen
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Default RE: Top Flite B-25 - Wingspan Models Add-ons Build Thread

When we cut through the skin of the fuselage we need to make sure that the turret cylinder fits cleanly through the hole. There is a fuselage former that runs directly under the area we cut, and after I cut through it there was some trimming needed. Also, there are stringers that run right next to the hole that may need trimmed as well. Using a rotary tool with a sanding drum on it makes for quick work to trim back anything protruding into the hole. Trim these until the turret can be inserted into the hole without anything interfering with it.

Sometimes when working on projects like this I’ll get an idea and then before I finish I’ll decide that it’s not right, or that there is a better way of doing it. If you look at picture #5 you see exactly one of these moments. As I said earlier, the turret can be controlled with the radio, but because I didn’t have a spare channel I had decided to use a manual switch to control the top turret. My initial plans were to put a switch directly on FL1 and have a pushrod to control it, as you can see in the picture. The pushrod was to extend out to the side of the fuselage where I could switch the turret on and off. But the more that I thought about the rod extending out of the side of the fuselage the less I liked the idea. It just didn’t “feel” right. So I changed my mind and placed it elsewhere. As you’ll see further on in the build thread I put the switch extension so that it exited right next to the turret itself. So why did I have the moment of confession to my “mistake”. First to show that your first ideas may not always be the best, so keep looking for better ways. Second, simply to explain why the switch in these pictures changes later on. I had already taken the pictures with the first switch location and there was no way to go back and retake the pictures.

Back to the build now. If you look at picture #6 you can see that they board FL1 is a bit warped. Included in the kit is a piece of ¼” x ¼” balsa stock that is used to strengthen FL1. The plans call for one piece on the forward end of the part. But after applying that piece I still noticed that there was a bit of a warp in the piece at the rear of the part. Unfortunately there was not enough balsa stock in the kit to make a second brace so I had to use my own wood here. I cut a second piece and glued in place behind where the drive motor attaches. This took the warp out of FL1 and made it strong enough to support the turret.

FL1 can now be test fit inside of the fuselage. I did find that getting the part in to the plane was a bit like solving a puzzle. FL1 needs to be inserted through the back of the cockpit, but because of the size of the opening it will have to be inserted at an angle. In order to rotate the part into place the sides of the fuselage need to be “flexed” outward just a bit to allow the part to rotate in to place. Once I figured this out it was a very simple process of getting FL1 in and out of the fuselage.


Pictures
1. Trim off any parts of former or stringers that interfere with the turret being inserted in to the hole.
2. Trim off any parts of former or stringers that interfere with the turret being inserted in to the hole.
3. Test fit the turret to ensure it moves freely inside the fuselage.
4. Test fit the turret to ensure it moves freely inside the fuselage.
5. First placement of an on/off switch. See further on in the thread for new switch location.
6. Part FL1 is slightly warped.
7. Apply medium CA to balsa stock used to strengthen FL1.
8. Forward and rear stock added to FL1.
9. Test fit FL1 in fuselage
10. Test fit FL1 in fuselage

Until next time

Ken
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