What's wrong with this pic?

[captain_john]

Give up?

OK, I will tell you.

I drilled the right elevator stiffeners with fore and aft reversed! The FORE distance (see plans in background) is supposed to be 1/4" not 3/4" and vica-versa.

My question is now quite obviously, what to do!?

I am composing an email to Scott Risan once again and asking him if this is salvageable, as I DID drill the skin with it. I expect him to tell me that the trailing edge will be difficult to buck and to add another rivet on the leading edge the required distance from the spar. Aside from that it should be ok.

Am I on the right track? What do you think?

DAMMIT ALL! This stuff always ticks me off! I didn't catch it until I was deburring and thinking about how hard it will be to buck those trailing rivets!

CJ

[captain_john]

...another pic of me in the process of screwing up.

CJ

[Snap]

CJ,
That is a very pretty blue that you have. What is it? and who makes it?

[captain_john]

That Sir, is my right elevator skin, made of .020" thick 2024 T3 Alclad aluminum and the stiffeners (made of the same) are cleco'ed to it. It is made by Kaiser Aluminum and CNC'ed by Van's Aircraft. In it's most recent form, it is screwed up by ME!

I have one suggestion from a friend to use the parts as is, drill the specified leading edge hole 1/4" from the end of the stiffener and to pro seal the trailing edge to prevent it from cracking.

Does anyone have another option to salvage this material?

I should really pay more attention to the PLANS!

CJ

[darrylDog2000]

The real issue here is all about compromise. If you’re willing to cut corners here you might be more willing to cut corners later on something more important. The replacement cost of the stiffeners probably isn’t too stiff. And, Vans ships pretty darn quick too.

[captain_john]

New parts is always a safe answer, and I may do just that. I am looking for opinions and options for the sake of discussion.

If I do get new stiffeners, what of the skin? Could I keep it and putty the end holes when I paint it?

What is the real harm here? I see it as a potential crack failure on the trailing edge... probably the reason Van says to maintain 3/4" from the end.

Do you see anything else?

I dare say having a rivet this close to the trailing edge could IMPROVE handling due to a crisper edge, assuming it doesn't crack.

Another problem, and probably my biggest is the inerference of the shop head against the opposing stiffener.

I am leaning towads new parts now.

CJ

[Spike]

Buy the part and move on. If the decision is this difficult, theres a reason why.

[captain_john]

Well, it is in my nature to dwell in minutia.

Maybe it is why we build planes instead of buying them off the lot.

I like to ask, "Why?"

Why does Van say 1/4" or 3/4"?

Why does the part need a rivet here or a bend there?

Why... why... WHY!

CJ

[Spike]

Well since you asked, here is what I would say if I had to guess. Structurally I would think that being 1/4" from the edge would actually be better than 3/4" from the edge to reduce skin flexing relative to the edge of the stiffner. It would seem to me that less movement would mean less chance of cracking. However, that rivet is going to be rough to set. How about using a pop rivet in the outermost hole closest to the bend? On the other end of the stiffner put in an additional AN flush rivet (assuming you can meet edge distance and pitch requirements). That would be the solution that I would float by Vans. Either they say go or the say no go. The rest is up to you. Let us know what you decide.

-- John

[darrylDog2000]

I would say that 1/4 inch is just fine and here's why. Go pick up any of your ribs and measure the distance of the holes in the flange from the edge. I'll bet you can't find one that's more that 1/4 inch away.

[svanarts]

My question is now quite obviously, what to do!?

I am composing an email to Scott Risan once again and asking him if this is salvageable, as I DID drill the skin with it. I expect him to tell me that the trailing edge will be difficult to buck and to add another rivet on the leading edge the required distance from the spar. Aside from that it should be ok.

Am I on the right track? What do you think?

CJ

Yep, you're on the right track. This is the first of many screw ups. Once you get to a certain number of screw ups, you get used to it. You fix it and move on. I think you have the right answer. Use the stiffener you have, don't forget to curse loudly when trying to set that rearmost rivet.

The thing is, if you're building a show plane, then get a new skin and start all over so that all the holes match up. If you just want a plane that has some character to it that is a kick in the pants to fly, make a note of your mistake so that you don't repeat it elsewhere and move on. That's the key, keep moving. Keep building!

[arffguy]

"Why does the part need a rivet here or a bend there?

Why... why... WHY!"

-Following standard aircraft building techniques usually. (edge distances etc.)

Really though:
If you don't mind lines of pop-rivets showing then I exactly agree with Spike:

"How about using a pop rivet in the outermost hole closest to the bend? On the other end of the stiffner put in an additional AN flush rivet (assuming you can meet edge distance and pitch requirements). "

[Heli-Wrench]

I hope I'm missing something when you guys say Pop rivets. There are real aircraft pull rivets called Cherry Max rivets. Yup, they come with an aircraft price tag, but they are actualy ment to hold a load.

P/N CR3212 are Nominal sized and counter sunk.
CR3242 are Oversized and counter sunk.

Oversized are very nice for those times you, "adjust" a hole but don't want to go up to the next rivet size.

[Spike]

Hmm, missing something like what? We are most definately referring to AN quality pull rivets. Not the typical rivets you would get at a hardware store. Is that what you mean?

-- John

[arffguy]

I hope I'm missing something when you guys say Pop rivets. There are real aircraft pull rivets called Cherry Max rivets. Yup, they come with an aircraft price tag, but they are actualy ment to hold a load.

I wonder if this should be a new thread here. Maybe it has been addressed on other lists but I don't know.

Van's puts "blind-rivets" in the kits but they are not Cherry rivets nor are they priced like Cherry rivets($$). They look alot but not exactly like hardware store rivets. The plans allow you to use them occasionally when you can't get an AN rivet in a hole. Also they are used to attach the fiberglass tips. They are driven with a regular home type puller instead of a Cherry puller ($$). When I tried to research them I couldn't find them in my aircraft mechanic books. (I have not really dug super hard). However I went to Sac Skyranch (aircraft parts house) they said they had never heard of or seen these type rivets-i.e. CS-4-4, LP4-3, MSP-42 etc. So does anybody know where Van gets his blind rivets? For that matter-another source?

[RV6junkie]

A Monel MK 319 BS steel shank pop-rivet would work well here. It's a simple mistake, fix it...and move on. There will be other mistakes - some you can fix - others that will require new parts.

Don't feel bad, I built two left ailerons and two right flaps for my -6. With all of the cracks in my rudder, I could use a new one of those now as well.

[captain_john]

I got the word from Scott Risan. He says:

John, the only real problem will be driving the trailing edge
rivets. It can be salvaged by adding a couple rivets to each
stiffener. You'll have to abandon the aft most rivet holes. With
these, set a flush rivet in the skin only (426AD3-3), then drill a
3/16 hole in the stiffener hole to clear the shop head of this rivet.
(you'll have to drive these 'skin only' rivets before you do the
final bend on the skins....otherwise you won't be able to access
them)
Drill the correct holes at 1/4" and 3/4" and treat it normally. The
spacing at each end will be close, but not noticable once painted.

the only other option would be new skins and stiffeners.

I like his idea and am proceeding with it. It makes perfect sense! The dummy rivet will alleviate any potential for cracking and the shop head will only protrude marginally, if at all over the top of the stiffener!

BRILLIANT!

Thank you all for your input! This made for a perfect learning experience for me and an excellent way to visually share the knowledge! Thank you for setting up the forum, Spike & Patti!

CJ

[Spike]

No problem CJ. Im glad that this can be of assistance. That was the goal when we started Hopefully we can be more help in the near future.

-- John

[captain_john]

BTW... assembled it tonight ala Scott Risan from Van's method.

As we say up here... Wicked AWESOME!

I am thrilled with the end product! The skin is formed and I am now onto the job of building the skeleton and the much talked about LEFT ELEVATOR AND TRIM TAB!

CJ