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I’m a bit confused with the operations we need to do on the wing attached blocks. Are we supposed to drill them to 3/8 inch while on the spar (they start out at 1/4 inch), remove them to drill the blocks to 1/2 inch? That would leave the home on the spar at 3/8 inch. What’s confusing to me is that the directions car to use the drill guide to make the 3/8 inch hole, implying that the starting hole is larger than that.

Am I supposed to drill out the hole in the block 1st to 1/2 inch?

it also seems like this drill procedure should be done after the wing spars are mayed because that way you ensure the Spar pin holes will be aligned.

Hi there.....HALT right there! I can only speak for the 'A' model, but the holes remain small, in my case at 1/4" diameter right up until mounting the wings to the fuselage. The idea is that you spend hours (in my case) fluffing around checking, double checking then doubting your self and then do some more checking to get your wings aligned as perfectly as you can in respect to equal dihedral either side of the fuselage, centred within the fuselage and the angle of attack correct to the fuselage and then once happy, well maybe go and make another cup of coffee first. And THEN proceed to drill the whole assembly, both wings and fuselage while clamped in position all at the same time up to the final bolt size in baby increments. Don't go for gold on your first go. Do one hole at a time, put a bolt in and then work your way slowly and carefully through the rest of the holes. I am sure that if John Monnet was watching over my shoulder at the time he would have told me to just hurry up and get on with it, but I fluffed around for two days in total just to drill 4 holes. Good luck, my inner OCD just made me bloody slow.

Amen brother! Proceed with extreme caution! <Follow the direction to the letter!!This is your last best chance to get a straight and true airframe. I bought some piloted double margin drill bits just for this task.

I'm a big fan of drilling the spar to size on the press, and then using a bushing to locate the hole in the fuselage. I thought that became standard on the B model?

Hey guys, thank you for the very enthusiastic words of caution!

I am appropriately nervous on drilling these blocks. Just to clarify, I’m on page SNB-w08, not SNB-f02. Well, technically I am onSNX-wc02 since I’m doing a conversion.

Just making sure I don’t muck this up. Actually, reading through the wing rigging notes, it seems like really the best thing to do is to drill the wings and the wing attach holes in the fuselage together to 1/2 inch

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Bryan Cotton wrote:I'm a big fan of drilling the spar to size on the press, and then using a bushing to locate the hole in the fuselage. I thought that became standard on the B model?

That's how I did it too, much easier and accurate. My Sonex has 190 hours now and counting.
Cheers

Hi, I am at WXB-W08 as well. I am having pretty much same confusion.
It seems that Sonex now wants us to do rigging without the fuselage for the B model.
I am worried with this procedure since the provided drill guide is not even concentric

alphapapafoxtrot wrote:Hi, I am at WXB-W08 as well. I am having pretty much same confusion.
It seems that Sonex now wants us to do rigging without the fuselage for the B model.
I am worried with this procedure since the provided drill guide is not even concentric

PXL_20240121_065627484~2.jpg

It definitely doesnt look concentric. I can see swarf. I would first clean that up with a round file to make sure it isnt just the swarf making it seem non concentric. If it's then not concentric, dont use it. Ask Sonex for a replacement. Or purchase some bushing stock.

When I used this method on my A model, it was at the time frowned upon Sonex, but believe me it is a lower risk method than the piloted drill method. That would be why they changed the procedure. I used bushing stock 3/8" OD x 1/4" ID bushing stock.

I made my own drill bushing and purchased long bits. I also made an alignment pin from ground stock. If anyone wants to borrow them just email me and I'll get them to you.

Ed Grasso

alphapapafoxtrot wrote:I am worried with this procedure since the provided drill guide is not even concentric

That should be concentric. Like Steve said, I'd deburr the end and have another look.

Nice job Ed! My A-model alignment bushings are out there somewhere... They have done a few airplanes. My neighbor made them for me.