Friday, August 7, 2020

Started to install the F-7101 gear webs - 6 hours

I started the build session with making the new spacers our of 0.032" material. Easy to do as I have perfect templates with thicker material.


I then used AD426 rivets and scotch tape to hold/alight the spacers on the gear web so I could cleco in the F-902 bulkheads.

With everything set, I was ready to drill.


Spacers looked great!

The right side of the aircraft came out really good, but for some reason left side wasn't sitting correctly when I drilled. I noticed something was off when I tried to disassemble. Yup, sure enough, the alignment is all sort of off.  I believe I didn't have the keeper cleco in the left side gear web correctly and as a result I misdrilled the F-902 bulkhead. Darn...I gotta order that new part.

I decided that it's best I just prep the gear webs for final drilling to ensure a great fit. I spent some time really trying to get a good radius on the 0.063 material so it will nest well with the F-717 longerons.

Then I drilled the top line of the gear attach webs. It least this turned out well.




Wednesday, August 5, 2020

Test fitting the F-7101 gear web - 1 hour

I did some test fitting with the F-7101 gear web. I decided to drill one keeper hole on each side to help keep things straight and in line.

Once I had that figure out, I test fit the F-902 bulkhead and gear web and realized the 0.063" spacers I made are too thick. I will need to make them again out of 0.032" material.



Tuesday, August 4, 2020

Messed with the fit of the F-902 bulkhead - 1.5 hours

Tonight I didn't spend a big day in the garage. I took a good look at the fitment of the F-902 bulkhead with the F-717 longeron. The bulkheads seem to want to lift the F-717 just a bit so they do not sill parallel with the angle of the bottom skin. Both the bottom mounting tab and the flange impede the F-717 sitting where it should. So some very slight and careful adjusting of the bottom flanges are necessary.

Looking much better....The F-717 sits parallel to the bottom skin.


Monday, August 3, 2020

Worked on F-796 B,C,D, and made new F-713 longerons - 10 hours

Now that Van's has confirmed that it would be best that I made new F-713 auxiliary longerons, I now need to wait for new one's in order to move forward. Darn...Today is a holiday as well and I have both the time and the motivation to keep going.

I decided to at least start rough cuts to the F-796B angles and the F-796 C&D spacers. I won't be able to finish fitment of these until I get the new longerons in, but since I had all of the tools out. Why not get a jump on it.



Next I decided to make the spacers I need between the F-7101 gear attach web and the F-902 bulkheads.

I was still making really good progress and it was not even noon yet. I started thinking to myself. Why not just make the F-713 longerons. I have more than enough of the appropriate stock material. So I decided to bite the bullet and make them. The curve is easy enough to trace and cut out.

The time consuming part was to properly file down the web. It took a few hours but I managed to do a really nice job. By 6:00pm I was ready to start fitting them to the fuselage.

Learning from my previous mistake, I centered the line on the inside face of the angle. This time the fit around the F-902 bulkhead is excellent.

I managed to get it all carefully drilled through the engine mount bracket. Not a quick and easy process....slow and careful as well as tedious. But they are successfully replaced.







Sunday, August 2, 2020

Fitting the F-902 Bulkheads - 6 hours

Started the morning with drilling the bottom of the F-684 gussets.

Next step I drilled the #19 holes for the nutplates.

Now that I have everything fitted up. I double checked my edge distance on the lower engine mounting brackets and I have about 0.240" edge distance so well within min. requirements.


Next I fitted up the F-902 bulkheads and then I noticed that the F-713 Auxillary longerons do not sit nicely in the cutouts of the F-902 bulkheads. Its like the longerons are too low...




I cleco'd on the F-7101 gear attach web and that too needs to be trimmed along the top in order to sit correctly. I'm really scratching my head on this one. After a bit, It finally dawned on me what I had done... The instructions on page 8-8 have you "draw lengthwise centerlines on Auxiliary Longerons F-713-L&R...". I assumed they meant the backside of the longeron and I drew a line perfectly down the center. It now occurs to me that if I had drawn the centerline based off the inside face(s) of the angle and drilled according to that dimension then I would have the correct fit as the longeron would be offset the 1/16" from where I currently have it placed.

Makes so much more sense now. That's why I was having such edge distance issues on the F-684 gussets, they were being placed 1/16" too high.

What happens if I trim the bulkheads and gear attach web to accommodate the lower longeron where I drilled it?. I did some checking on this. I am going to run into an edge distance issue on the F-796B-L/R tank attach angles.






If I follow the plans, then edge distance for the AN3 bolt is ok (No room for error though). However if I maintain the longeron where I have it...the edge distance is blown. I did up a test piece to see how much material I had to work and its just not enough.

I called Van's and the advice was if I already had it riveted in, then I'd just have to go with it. But since everything is just cleco'd the best option is to redo the F-713 longerons. Crappy, but it is the right thing to do. Order was placed for new parts...we will come back to this another day.

In the meantime...I checked the fit between the F-902 bulkhead and the F-7101 gear attach web and I do have a bit of a gap. Seems this is fairly common among the various builders websites so I too will be making a space for both the Left and Right sides out of 0.063" material.
 




Saturday, August 1, 2020

Worked on the F-684 gussets - 10 hours


Spent the entire day working on the F-684 gussets. Ughhh these were not easy to work with! 

Things started off all right with making the gusset, however I didn't pay enough attention to where the 1/8" dia holes are to be drilled. I soon figured out that I drilled them in the wrong location and I was going to have edge distance issues on the firewall angle. Crap. 

Well...I have one sq ft of 0.063" material so I can easily make new gussets. But I decided that I was going to make a paper template first to double check all fit before I fabricated new pieces.  I drew up a template on autoCAD and clamped/cleco'd it to the assembly. 


After making a few slight adjustments to help with increasing edge distances. I cut out my new gussets.
 

It was an immense amount of work, but I am pleased with how they turned out. 

Friday, July 31, 2020

Installing the F-717 longerons to the Engine Brackets - 9 hours

Installing the F-717 longerons has been weighing heavy on my mind for some time now. Reading other build sites has noted that the edge distance at this location can be quite tight, and sometimes non existent if you follow the drawings.

Being mindful of this, I used a small piece of scrap aluminum angle to start measuring things out. Using an edge distance of 1.5 times the bolt diameter gave me a minimum edge distance of 0.28125" and marking the line on the angle at 0.500" (as per the drawings) leaves a scenario where theoretically it will work, but there is just no room for error, and for a guy doing this by hand in a garage. Its not great.




So taking the advice from other build logs, I moved the center-line of the bolts 1/16" inboard. The dimension is then 7/16" (0.4375") rather than the specified 0.500". This will allow me to have a larger margin of safety on the edge distance of about 0.373". Of course I called Van's before tech support closed, just to double check if they had concerns with my logic and the advice for me was build on.


Now its time to do the actual drilling. I started by marking out the lines and using a punch to set the center point of each hole.

Next step I drilled all of the holes to #40 so I can get a good look at the center lines drawn out on the mounting brackets below.

I then started drilling each hole to #40 and inserting a cleco. Then I started working my way up in drill sizes. #30, #25 #21 and finally ended with a 3/16" reamer for the AN3 bolt. Im really pleased with how it turned out. 



By the end of the evening, I had just enough gas left to finally complete the cutouts for the F-717 longerons. I hesitated to do these right at the beginning as I did fear I would mess up the longeron drilling. And who wants to keep cutting down multiple angles...not me.