National Aeronca Association Bulletin Board

Kelley's been really cool to give me a 24hr pass every once and a while; so I'm doing my best to put it to good use.

First up I trimmed the butt plates to final dimension, per the drawings.



Next we ripped the bevel; 10* on the front and 7* on the rear. Using the feather board to keep the spar pushed against the fence, two of us were able to run the boards; one feeding and one catching.

I was using a lower grade contractors saw with a brand new 80T blade, so the cut was smooth but care had to be taken to keep the spar square on the table. You can see how the throat plate sits lower than the table which can create the incorrect bevel. Little things to watch for.


nkh

Next, the spar doublers were glued and clamped together. Same as before; resorcinol on the plate and spar; clamp for 24 hours and then trim the top and bottom edge with a hand plane being careful not to dig into the spar.





In this picture you can see how the spar are setting on 4 saw horses that have been shimmed to make the blanks lay completely flat. Ideally you'd have a 20' dead flat table to keep the spars from bending and warping, but sometimes you adapt, improvise and overcome.



nkh

Time to drill holes......

I've talked about doing this for 2 years and finally the time came to put up or shut up. To be honest, I had to call in reinforcements to make it through the process.

Here are the much talked about drill jigs that Derek Landstrom drew up on AutoCAD The white painted ones are Version 1; which after getting cut out with the laser we realized a couple of the holes were off. So we came up with Version 2 (Green and red in subsequent pictures,) that had all the corrections needed... but we forgot to add a couple holes and burned the root fitting holes at 3/4" instead of 7/8". Luckly, between Version 1 and 2 we had everything correct at least once. Version 3 is being drawn up now.

If you look at the drill jig, you'll notice two 3/8" roll pins on the far left and right of the jig; these locate the jig to the proper height on the blank. Next you'll see several rectangle windows with a pointer; these alight the holes to the correct running dimension on the blank. So all you have to do is pull the tape measure once and mark the respective length on the spar, then slide the drill jig until the pointer lines up with the pencil mark. Clamp everything in place and drill some holes.







Talking advice from David Johnson, Georgia Mountain boy himself... I mic'd the brand new forstner bits and they were all oversize to varying degree. So I chucked them in the neighbor's lathe to trued them up, which was surprisingly easy because it was only cutting tip that was out of spec. On the same note... the bushings were all undersized. After drilling test holes before and after truing the bits, the bushings would press into the holes with a little resistance. Perfect.




The man himself, Derek Landstrom, trying out the jigs.



I told him if he F'd up we'd have some words...



nkh

By the end of the day (4:30am) I had all four blanks drilled out. We test fit the butt fittings and main strut fittings; and everything lined up great. You could push the bolts in by hand; no hammer needed!















Next I'll drill for the drag/anti drag wires....

nkh

Great to see it and very nice looking work!

When you going to answer my email???

How did the Maule checkout go?

Joe

crap... too many swords in the juggling act...

Hand off went fine. The guy tossed me the money and said "Lets go flying!" I did get a ride back to Deer Valley in his C208B Caravan; That was cool.

As for the Maule; not impressed, liked we talked about. It was nice to have 8 hours of fuel at times. I'll post some pics.

nkh

Very Nice. Bet it felt good to get something you been dreading behind you. My heart did skip a beat when I saw who was running the drill press though. Looks like Derek's drill jig idea is working out good. Good ideas for the rest of us! David J.

I'm wondering.....after all the pressure of drilling the spars, did you relax with some of the 'Georgia Mountain Dew' ?

MikeB

MikeB wrote:I'm wondering.....after all the pressure of drilling the spars, did you relax with some of the 'Georgia Mountain Dew' ?

MikeB

Mike,

Nathan stopped by my house while ferrying the plane out to its new owner in Arizona. I still have a "few drops" of the special dew that he brought to the Middletown 2008 fly-in. Offered him a swig or three of it just to take the edge off of his flying most of the way across the country but he declined.

As I remember things, we ended drinking iced tea! Must be getting old...

Joe A

Nathan,

Glad things worked out with the Maule guy. Let me know if you can work any magic on the STC situation we discussed.

Joe

PS really glad to see you back fussing with the Champ. Time will be dear after the twins arrive.

I was able to drill the drag/anti-drag wires a couple months ago, unfortunately I didn't take any photo's of the process.
But I did follow David's advice and chuck the bit up in an air-drill and spin it as fast as possible and bolt the jig onto the
correct side of the spar.


Here's a picture I snapped last night while laying out the tip cuts... notice anything wrong?



nkh

OK, I'll bite. Got her a little upside down Tater! David J.

David, you should be able to pick it out easily from all the wings you've built.

Take a look at the bushing and drag wire holes and their location on the spar. The pencil line depicts the tip cut.

nkh

Oppps, did you drill the drag wire holes the wrong direction, they should be closer together on this side..............

Hey guys!

Tell me you didn't....David J.

Nathan,
You don't need that extra drag wire hole to the tip. Unless you want it.
Paul