Trim Tab


Trim Tab 4 (1.5 hours)

Tonight I set about making the rib-let for the elevator.  I started by lining the trim tab up with the elevator, and determining the amount that needed to be cut off from the elevator tabs.  My trim tab is not perfectly straight, so I made sure to match that line.  Without a square I don’t think anyone will notice.  (yeah, right…) Then I cut off the tabs.  This was pretty painful considering all the work that went into making those tabs.  This whole tab system for the trim tab and elevator is pretty painful, and compared to the rest of the kit so far, fairly difficult… and needlessly so.  I think there are a couple other ways van’s could tackle this that would be just as effective and far easier.  I bet the RV-14 trim tab won’t be done like this…  After cleaning up the cuts, I again lined up the trim tab to check the clearances.  The alignment and clearance is perfect.  My first rib-let came out darn close to perfect, but I can see a few improvements that I can make.  It only took 15 min, so I might as well bang out another one. I’m tired now, but I’ll post more details of how I made the rib-let later. 20130811-193750.jpg

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Here are the tabs marked for cutting. 20130811-193810.jpg

After cutting…20130811-193818.jpg

Cleaned up enough to check for clearance and alignment. 20130811-193825.jpg

Clearance looks good. 20130811-193832.jpg

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I meant to take pictures of the rib-let before I bent it, and with it installed, but I was caught in the moment.  Here’s I’ve unbent it by hand to read the measurements I had used when I make the next rib-let.  The measurements for width / angle were good, but I want to shorten the length, properly align the ends, and slightly change my bend technique.  I plan to knock this out tomorrow.20130811-193846.jpg


Trim Tab 3 (2.0 hrs)

Today I met Mike at the hangar as he had agreed to give me a hand with the trim tab. I was able to complete the dimpling and countersinking of the skin and the spar, and match drill the hinge to the trim tab. Mike has several different thicknesses of hinge at the hangar and we used a slightly larger width to solve my edge distance issue from yesterday. Finally we set up the trim tab to align it with the elevator as shown below in the pictures. Unfortunately my bends on the end do not allow for the proper clearance alignment. The inboard edge is sticking out by approximately 1/8 inch.

Afterwards we flew to a fly-in at Smoketown Airport in PA. (You can see Mike’s post here.) Great flight, good food, and several cool aircraft on the ground. We also got the opportunity to see two other trim tabs to consider my issue. After that it was very apparent that my error is on the elevator tabs. I’ve bent them too close to the tab. My solution will be to cut the tabs off and install a riblet. I’m hoping to tackle that later this evening or tomorrow.

Here is the trim tab in line with the left elevator. 20130810-163508.jpg

And the deviation…20130810-163518.jpg

Mike on the ground in his RV-7 at Smoketown.20130810-164219.jpg

On base.20130810-164229.jpg

Just for fun I used my MotionX GPS on the iPhone to track our flight. Here are the screen shots. 212mph max. The average speed is a little bit low because I recorded during taxi and takeoff. The GPS signal dropped off at spots.. but heck, its just a cheap iPhone app. Did the trick for my purposes today. 20130810-164607.jpg

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Trim Tab 1 (3.5 hours)

First an update on the left elevator: the parts will arrive Tuesday via FEDEX ground.  I should be caught back up in a weekend.

On to the trim tab.  The first project was to remove the blue plastic in order to begin work on the trim tab.  Next I used Mike Bullock’s brake to bend the trailing edge.  I used my hand seamers and a few rulers to complete the trailing edge bend.  After the fiasco of screwing up the tab on the elevator, I set about bending the tabs on the trim tab today.  After discussion with Jack during the setup for the Gathering tomorrow, I think I had the right approach in mind.  I bought some oak planks to use as my bending blocks.  Double sided carpet tape and two clamps held everything in place.  This is extremely easy to mess up and a severe pain in the butt.  In the end I was successful.  Both sides are bent the appropriate amount and in the correct location.  There are a few areas where its not the prettiest but its perfectly airworthy and I’m happy enough with the result.  This is one area that you should definitely take your time with and practice.20130712-203759.jpg

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I got a flat yoke from Avery tools.  This yoke doesn’t accept a die in the upper receiver but acts as the flat die itself.  This should allow me to finish up those few pesky rivets on the rudder and elevator that I could not access.20130712-203818.jpg