Archive for category Elevators
Trim Servo Installation (2/20/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 20, 2010
1.7 Hours -
My electric elevator trim kit finally arrived last night and I was anxious to get into the garage to install it. However, I was still confused by the plans (or lack there of). When I get stuck, I consult multiple on-line sources, primarily consisting of the forums at vansairforce.net and several builder’s sites. As usual, I was slightly relieved to find that many builders have had problems at this stage.
The first problem is finding dimensions on the plans. They were well hidden, but I managed to find them. The second problem is that many builder’s find the listed dimensions to be wrong. Following the dimensions in the plans will often result in the trim servo being mounted off center. The third problem is getting the servo to fit in it’s brackets without having to fabricate a spacer. Thanks to Brad Oliver’s build site, my servo didn’t need spacers.
The electric trim kit contains a servo, switch, position indicator, and associated hardware. Van’s also throws in the z-brackets that are used to attach the servo to the trim access cover, new control horns that don’t require trimming, and a bag of assorted hardware.
The electric trim kit contains a servo, switch, indicator, and associated hardware.
The trim servo is small and light.
The kit also included two z-brackets for attaching the servo to the trim access cover.
First off, I needed to find the dimensions for marking the trim access cover for proper alignment of the z-brackets. Once I located these on the plans, I drew corresponding lines on the access cover. I then clecoed the servo to the z-brackets and lined up the assembly with the marks on the access cover. As with many other builders, I found that following the plans would leave the servo out of alignment. In order to center the servo, I found that I needed to move it over a mere 3/16ths of an inch.
Following the dimensions given in the plans, the servo was slightly off center.
After moving the z-brackets over about 3/16", the servo lined up correctly.
Once everything lined up, I clamped the z-brackets in place and used them as a template for match drilling the trim access cover. Then, I deburred and dimpled the access cover and z-brackets. In order to properly seat the servo without spacers, I countersunk the two aft z-bracket attach holes for NAS1097 rivets rather than dimple them. By countersinking these holes, the shop head of the rivet will sit slightly lower than it would in a dimpled hole. NAS1097 rivets are used because the access plate is not thick enough to accept a standard countersink. The other four z-bracket attach holes were dimpled for standard rivets. (Thanks again to Brad Oliver’s build site for this tip.)
After getting everything lined up, I drilled the z-brackets to the cover plate. You can see the original line per the plans and my line, where I actually installed the brackets.
The trim access plate was dimpled before priming. I choose to use NAS1097 in the two aft holes per Brad Oliver's build site.
After everything was dimpled, I primed everything and then riveted the assembly together. The servo fit and alignment was perfect.
Primed, riveted and ready to be installed. I need a 9V battery so I can test it.
Finally, I switched gears and worked on the trim tab a bit more and final/match drilled the control arms to the tab. The next step in the trim tab is to start attaching the hinge and the plans had me thoroughly confused, so I decided to call it a day.
The control arms were drilled to the trim tab.
Trim Tab Bends Completed (2/15/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 15, 2010
1.0 Hours -
Although many builders complain about bending the trim tab ends, I was feeling confident after my success on the elevator tabs. However, when I went into the garage to tackle the trim tab, I quickly lost some confidence when I realized my newly constructed bending blocks were too small.
The blocks were not long enough…I didn’t even get the wedge to be as wide as the trim tab itself. I’m not sure how I could have managed to do this unless I used the outboard end of the trim tab as my guide. The outboard end is significantly shorter than the inboard side.
Fortunately, I seem to have a lot of extra wood around the garage now. So, I made a new set of bending blocks. This time, I made sure they were long enough and they turned out better than my first set.
Before bending the trim tab ends, I had to finish the edges of the trim tab. This would be almost impossible if I bent the ends first. As usual, this was a simple matter of using the Scotch-Brite wheel and some emery cloth.
Once the skin was prepped, I carefully aligned the bending blocks with the inboard trim tab end and clamped it all to the edge of the table. Using a wood block, I first bent the bottom tab down. Then, flattened it with my rivet gun and flat set. The whole procedure was repeated by bending the top tab up and flattening it.
To bend the tabs, a bending block is used to bend the bottom tab down. Then, the bottom tab is bend up. The bends are made crisp with a rivet gun and flat set.
The inboard bends are complete. The final result will be known when the blocks are removed.
The inboard bends look good!
The inboard end looked good, so i moved on to the outboard end. Both ends have small dings in them from the rivet gun, but I’m probably the only one that will notice these…especially if it is painted. Otherwise, the bends are nice and crisp with no waviness.
The entire process is repeated on the outboard end. Looks good, no complaints from me.
The final bends are nice and crisp. I'm happy with it.
Finally, I wrapped up the day by finishing the edges of the trim tab spar. I hope that trim kit gets here soon so I can move forward.
Trim Tab Started (2/14/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 15, 2010
0.8 Hours -
While waiting for my electric trim kit to arrive, I’ve been itching to work on the plane. I need the trim servo before I can move forward on the left elevator, so I decided to start working on the trim tab and get as much of that done as I could prior to the trim kit’s arrival.
First off, I had to complete the trailing edge bend of the trim tab. To do this, I simply placed it into the same bending brake I used for the elevators and bent it until the skin could be easily attached to the trim spar.
I quickly assembled the trim tab skin and spar to check my trailing edge bend.
The trim tab ready for bending
Next, I made a set of bending blocks for bending the ends of the trim tab. These are bent in essentially the same way that the tabs on the left elevator were bent.
Finally, I ordered and received the infamous $9 drill bushing from McMaster-Carr. This bushing will be used to properly align a hole that needs to be drilled through the elevator horns when it comes time to attach the elevators to the horizontal stabilizer. The bushing will help me center the drill bit while protecting the center bearing of the horizontal stabilizer. As with many other builders, I found the outer diameter of this bushing to be slightly too large. To fix it, I chucked it in my drill press and used some emery cloth to slowly decrease the diameter until it would fit through the horizontal stabilizer’s center bearing.
The infamous $9 bushing from McMaster-Carr.
The diameter of the bushing is slightly too large. To reduce it, I chucked it in the drill press and took some emery cloth to it.
Bent Left Elevator Tabs (2/7/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 7, 2010
1.0 Hours -
Thanks to a refund check from Uncle Sam, I ordered my electric trim kit from Van’s (yes, I’ve tossed out the idea of manual trim). Unfortunately, this puts much of my left elevator work on hold while I wait for the trim components to arrive. According to the plans, it is easier to install the trim servo prior to riveting the left elevator. This way, you still have access to both sides of the servo. Once riveted, you only have access through the trim access panel.
With this in mind, about the only things I can do are to bend the elevator tabs and start the trim tab. I opted to bend the elevator tabs today.
First, I placed my bending blocks into position. I used double-sided tape on the angled sides to hold everything in-line and clamps on the entire assembly to make sure everything was nice and tight against the table. Once the blocks were set, I used another wood block to start bending the bottom tab down.
My bending block setup for the elevator tabs.
Once the bend was as bent as I could get it with the wood block, I pulled out my rivet gun, put in a flush set, and turned the pressure way down to 10 PSI. The flush set was, more or less, used to beat the bend into submission. Before the rivet gun, the bend was about 75 degrees. The rivet gun allowed me to reach the final, 90 degree angle.
This was then repeated by bending the top tab up. The top tab has to be over the bottom tab in order to prevent water from entering the elevator. The final result was pretty descent, although, the rivet gun did leave a few dents, but these won’t be visible once the trim tab is in place.
I used a wood block to start the bends. My rivet gun, with a flush set, turned way down to about 10 PSI, was used to finish the bends.
For now, I’m happy with the bends. However, I’ll wait to place my final judgment until the elevator is riveted and I can see how flat the bends are. I really thought this would be harder and take longer since so many builders have problems with it. In all honesty, I expected my bends to look horrible, leaving me no option but to cut the tabs off and replace them with a homemade riblet. Looks like I may have to wait even longer to use my bending brake.
Not bad. A few dents from the rivet gun, but I'm happy with it overall. Does this mean no riblets?
To wrap up the day, I started to rivet the counterbalance skin to the main skin. As with the right elevator, two rivets are set in both the top and bottom now so that you don’t have to use blind rivets later.
As with the right elevator, two rivets are set on both the top and bottom now to avoid pop rivets later.
Left Elevator Skeleton Riveted (2/6/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 6, 2010
0.8 Hours -
This afternoon, I spent almost an hour riveting the left elevator skeleton together. Overall, this was fairly simple. However, as with the right elevator, the elevator horn didn’t seem to want to line up properly. After a little squeezing, twisting, etc, I managed to get it riveted on. Not many pictures of this assembly as it is almost identical to the right elevator.
The left elevator skeleton is riveted. Once again, the elevator horn was an issue, but simple overall.
Left Elevator Skin Finished (2/3/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 4, 2010
1.0 Hours -
I’m finally finished deburring, dimpling and priming the left elevator. Well, I’m done except for the trim tab components!
Finishing up the elevator skin was straight forward. Just a lot of deburring, followed by dimpling a bunch of holes that could all be reached by my pneumatic squeezer…simple! Next, time for more priming.
The left elevator skin is primed and ready for assembly.
Tonight, I also made my bending blocks for bending the tabs on the elevator skin and also on the trim tab. The blocks are just a piece of wood that has a wedge cut out. The wedge mimics the final bend angle of the elevator skin. If I’m unable to get a good bend, I’ll cut the tabs off and make riblets instead.
Simple wood bending blocks are used to bend the elevator and trim tabs. If this doesn't work, I'm making riblets!
Left Elevator Skeleton Ready For Assembly (2/2/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 2, 2010
1.2 Hours -
Tonight, I finished deburring and dimpling all of the left elevator skeleton parts. Once deburred and dimpled, it was primer time once again. As usual, I roughed them up with a Scotch-Brite pad, cleaned them with acetone, and sprayed them with NAPA 7220 self-etching rattle can primer.
That's right! More primer. Here, the left elevator skeleton is ready for assembly.
Deburr, Dimple, Countersink, etc. (2/1/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on February 1, 2010
1.3 Hours -
No pictures again. Deburred, dimpled, edge finished, and countersunk for over an hour. All that is left is to dimple the main spar, dimple the skin, and prime everything.
Left Elevator Continued (1/31/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage, Tools on January 31, 2010
1.0 Hours -
Once again, my time to work on the plane was limited by other things that needed to get done. While I did have to go to work and do some necessity shopping (can’t build an airplane on an empty stomach), I have to admit that I was being a little lazy and just wanted to veg in front of the TV a bit too.
My 1.0 hours of project time was well spent though. I finished drilling the left elevator skin to the skeleton, disassembled the elevator, and started working to deburr and dimple all the parts. No pictures of this as it is essentially the same as the right elevator (and numerous other pictures I’ve posted about deburring, edge finishing, and dimpling). This should keep me busy for another couple of days as well.
On another note, I’ve been spending a lot of time looking at other build sites to see how people handled the bends on the elevator skin tabs and the trim tab ends. Some people construct a wood bending block per the Van’s instructions and have no issues. However, a lot of people cut the tabs off and make riblets instead. In anticipation of struggling with this, I bought a cheap Harbor Freight bending brake. Even if I’m able to bend the tabs per plans and forgo the riblets, this tool will easily justify it’s $35 price tag. Just bending a small piece of scrap aluminum was kind of fun (yes, I’m easily entertained!
I bought this bending brake in anticipation of making riblets for the left elevator and trim tab.
Continuing the Left Elevator (1/30/10)
Posted by Ethan Jacoby in Construction, Elevators, Empennage on January 30, 2010
1.5 Hours -
After getting a few thing done this morning, it was time to head into the airplane factory and continue working on the left elevator.
This time around, I decided to finish the edges of the skin before putting in the final bend. I thought this would give me a little more space to work, but, in the end, I’m not sure unbent was any better than bent. The edges were finished with a combination of using a vixen file, dove-tail deburr tool, emery cloth, Scotch-Brite pad, and Scotch-Brite wheel.
Once the edges were finished, I pulled out my homemade bending brake and put the final bend in the skin. I was much less nervous the second time around and the bend turned out just as good as the first one.
I wasn't nearly as nervous making this bend the second time around.
The elevator skin after bending.
Once everything was clecoed together, the bend looked pretty good!
After bending, I clecoed the skin to the skeleton. Once the skin was on, I clamped and final-drilled the elevator horn.
Finally, I clamped and final-drilled E-606PP to the skeleton and skin. This is another part that is only on the left elevator. It is a short spar that located where the trim tab will attach. It will hold the forward portion of the trim tab hinge.
E-606PP is another piece on the left elevator which is absent on the right.
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