Vertical Stab Bracket

[Justin Lewis]

I'm currently working on my vertical stabilizer bracket and I wanted to point out two things that might help.

1st, the template scale was off a bit. I rescaled the pdf making the template a bit larger. If you want a copy, let me know.

2nd, the tailboom has a dome rivit in the location that the bracket will attach. I intend on removing it but I'm working on a solution to either replace it with a flush or possibly include the empty rivit hole a part of the bracket bolt hole.

[Justin Lewis]

I was recently asked for a photo update of my vertical stabilizer bracket. Ultimately, I didn't like the idea of hammering on the steel in a vice and it's much too strong for a normal break. I got a little help from a machine shop which produced an outstanding result based on my templates. I've only done a little tweeking to get closer to perfection and I did have to heat and hammer the curve. I still have a bit more hammering to do but it's about ready to install. I'm away from my shop for a few days but I'll upload an image that can be used as a template when I get back.

The biggest issue I haven't solved yet is how I'm going to locate the lower bracket bolt through the airframe where the rivits are currently located. I may just accept an irregular shaped bolt hole but I'm concerned about a airframe crack in the longterm.

[homer bell]

Install a flush countersunk rivet, or just remove the rivet completely, your bolt will do what ever the rivet was doing before. Use a right angle drill to drill your hole thru the rivet hole into the bracket, not the other way around. Start with small hole.

[Justin Lewis]

Originally Posted by homer bell

Install a flush countersunk rivet, or just remove the rivet completely, your bolt will do what ever the rivet was doing before. Use a right angle drill to drill your hole thru the rivet hole into the bracket, not the other way around. Start with small hole.

Thanks Homer. I've already pulled one of the two rivits out. The other one is under the skin and apparently holds the stringer to the frame so I can't see or reach the head of that one. In the end, the two rivits are far enough apart that I can't include both of them in the single bolt hole AND they're too close together to try and avoid one of them all together. Currently, I'm planning on simply drilling like you said through the rivit that goes through the skin. I'll probably try to remove the back of the stringer rivit but the result will be a bolt hole with an edge that intersects the other rivit hole.

[Justin Lewis]

Originally Posted by Justin Lewis

Thanks Homer. I've already pulled one of the two rivits out. The other one is under the skin and apparently holds the stringer to the frame so I can't see or reach the head of that one. In the end, the two rivits are far enough apart that I can't include both of them in the single bolt hole AND they're too close together to try and avoid one of them all together. Currently, I'm planning on simply drilling like you said through the rivit that goes through the skin. I'll probably try to remove the back of the stringer rivit but the result will be a bolt hole with an edge that intersects the other rivit hole.

Here's the photo brackets so you can make a ballpark template.

[Sam Oliver]

OK, I find myself at this point today. Bending and installing the front bracket. And looks like I'll have pretty much the same problem you had. Did you end up leaving the rivet that is under the skin? After it is all said and done, Do you have a measurement or picture that would illustrate the distance your bracket is off the tailboom. I haven't seen anything in written instructions or videos that addresses this. As I struggled with geometry in school I'm trying to figure out the angles. Varying them can bring it in pretty close, or have it hanging out in the breeze. Within the limits of keeping the brackets off the existing rivets.
Thanks
Sam

[Charles Lewis]

Just a FYI all of my templates were printed wrong, twice. I finally got good ones lacking two not yet corrected. On small parts like the brackets you may not even realize why they don’t fit reall well. My templates were off a little over 1/16” per inch

[Sam Oliver]

yes, I scaled up the templates. I think they are correct after I scaled them up. And have fabricated a test one from aluminum as advised in the instructions. And just eyeballing it I'm sure I'm going to have the same issue as you had on the lower mounting point with rivets. But I'm also wondering how far the standoff is from the tailboom. I didn't actually get the vertical fin with my group 1. It's backordered until they don't know when. So I can't hold it up and kind of get an idea of how everything will go, not that it matters. If the first angles from the mount were 90 degrees say, then it would be easier to figure out. But looking at the drawings, construction video, and written instructions, it doesn't look as there is anything specific. Just make it vertical and bolted to the #4 bulkhead seem to be the only "for sure" part of the installation of that bracket.

[homer bell]

Bracket should end up within 1/8” of boom, less is OK. The bracket doesn’t have to be exactly like the template. I like to increase the distance between the bolts for extra strength. If you do this the bracket needs to be slightly taller between the bends. Bottom line is keep stress to a minimum everywhere you can.

The bracket should have nicely rounded bends. This bracket is .090 should be heated to bend the initial bends. Minor adjustments could be done to find tune it cold.

You keep trying to match that bracket perfectly and you going to end up making several brackets and doesn’t have to be.

[Sam Oliver]

Thanks Homer. Looking closely at Justin's pictures I can see the offset from the tailboom is pretty small. I'll just work with my aluminum test piece until i come up with a good fit.

Sam

[Fredy Irizarry]

Hi, New A600 builder here :-).

I have seen the reference many times to "use heat" when bending the tail fin brackets, but I am not sure "how hot" is right.

Does it have to be cherry red, just turning red, or can I use an infrared thermometer and heat to a specific temperature?

Another question is, the cool down, I just let it air cool slowly right?
Any advice would be greatly appreciated!

[homer bell]

Hot enough to bend easy . That will be a dull red color. Cool down is the important part, never cool to quick or you will harden it and make it brittle. Play the heat and take it away slowly.
Also, never make sharp bends like you would have in a brake, unless you make provisions for a smooth radius.

[Fredy Irizarry]

Thanks Homer!

I only need to heat the area around the bend line, right?, not the whole part?

And to cool it down slowly, would it work to put the part after heating to dull read and bending in a preheated oven (I think goes up to 450F), turn it off and let it cool?

[Al Behuncik]

Getting the radius not too small and letting it cool slowly is very important but also you need to heat the metal from the Inside bend side which will tend to thicken the metal in the bend area; heating the metal on the outside bend area will tend to stretch and thin the metal and weaken this area. Al