HS 405 main rib woes

prestwich · Post by **prestwich** » Fri Mar 10, 2006 1:51 am

OK, it's time for my first significant screw-up. One drawback to taking so long is that I forget what I've already done.

The stupid instructions say to "choose which ribs will be used on the right and which on the left and mark them." To me, that makes the choice sound totally arbitrary. I forgot that the 404 and 405 had been previously worked on, which creates a definite left and right.

The 405 has four holes that I drilled in the front flange. One of these goes through the 710, one through the 714, and two through the aft flange of the 404. All of them also go through the front spar. Do you guys remember that step?

So now I'm ready to drill the spar, the stiffeners, and the nose rib using the holes in the main rib. But, of course, the holes in the 405 main rib are in the wrong place, because I grabbed the "right" one and marked it "left."

I think I should buy a new part, because the flanges have already been match drilled to the skin.

But, I've got another issue. I don't see how to drill the matching holes in the other parts using the holes in the forward flange of the 405 anyway. This seems totally backwards to me. If the holes were drilled from the leading edge, I could use my long drill bit and they'd be straight.

Why the hell does Van's want you to try to drill these from the back? With a long bit, you're still at a big, big angle. With my angle drill attachment, the chuck diameter still forces me to a big angle. What did you guys do here?

And, I'm thinking of buying two new ribs, and drilling them from the front like I think they should be. Is there a good reason not to?

Thanks as always --

Jon, aka p'wich

prestwich · Post by **prestwich** » Sun Mar 12, 2006 11:14 am

OK, I'm an idiot. Now that I've calmed down, I see that I created my own problem by "working ahead" in the instructions. I drilled the forward flanges of the 405 ribs a month ago, but, actually, that step comes right *after* the "choose left and right ribs" step.

I was able to swap the fake left rib for the real one, and even though the right rib had been match drilled to the left skin, it lined up with the holes in the right skin, so I don't even have to buy a new part!

Also found, by checking builders' sites, that I needed to remove the rear spar to drill the mating holes from the forward flange of the 405. I actually was able to drill them dead straight by flexing the 12" #40 drill, and then opening them up to #30 from the leading edge side.

Build on!

captain_john · Post by **captain_john** » Sun Mar 12, 2006 11:25 am

OH, jeesh Jon... I didn't mean to leave you hangin there!

I didn't have my plans handy when I read your post at school, the cookie cleared the thread and there it went! I totally forgot about it!

If you are all figured out, okay... but next time so I don't need to dig out plans, can you use terms like rib, flange, web and spar so I know what you are saying. If we need specifics then we can talk part numbers.

Sorry...

CJ

prestwich · Post by **prestwich** » Sun Mar 12, 2006 12:10 pm

No sweat, CJ. I hate those damn part numbers myself. I guess the build manual is written like that to avoid ambiguity, but it's a major irritation!

Hey, this thing is moving right along. Pretty soon I'm gonna have to learn how to rivet!

Jon

gsimatos · Post by **gsimatos** » Thu Nov 09, 2006 9:37 pm

I see it has been some time since you wrote the above but I am at this same step to locate and drill ribs 404 and 405 on the forward spar. I don't find it very clear how you position the fore and aft ends of these ribs for drilling against the spar. Does anyone remember this step? Any help would be appreciated Thanks Gary

prestwich · Post by **prestwich** » Fri Nov 10, 2006 12:44 am

Gary,

Not sure that I understand your question, but a quick look back refreshed me on this part. Your skin should already be clecoed on at this point, that's what holds the 404 and 405 in alignment for drilling. Remove the rear spar for drill access. Does that help? If not, give me more detail!

Jon

gsimatos · Post by **gsimatos** » Fri Nov 10, 2006 2:03 am

Jon Thanks
Yeaah i think with the skin on i should be able to locate the ribs against the spar. I have been packing the blueprints around for a couple of weeks but tonite I left them in the hangar. I am gonna pound again tomorrow. I will let ya know how I make out. How far along are you with your plane??G

dons · Post by **dons** » Fri Nov 10, 2006 3:10 pm

I used the 404 to determine the postion of the inside two holes (the ones that don't go through the 710/714. I located them to ensure edge distance and pilot drilled them in the 404 and then used that as a template to drill through the 702 and 405. I also only cut done the aft flange of the 404 as much as necessary to have clearance between the 710/714, if you go by the drawings you will have to move the center two aft 404 flange holes even more towards the center of the flange. Don't just go by the dimensions on the drawings.

The outside two are the ones you really have to be careful with as there is an edge distance issue on the 710/714 as well as the 405. What I did was mark on all three parts the minimum edge distance and then make sure by trial fit and a lot of measuring that the holes were going to meet the edge distance rule on all pieces.

A couple of things I ran into ... 1) The edge distance on the most forward top/bottom holes of the 405 can not be met in the direction towards the front of the plane. I actually spent a lot of time worrying about this one, but if you carefully measure the raw parts you will discover it is just designed that way. 2) Keeping the 702 properly aligned with the skin is very very important while match drilling the 404/405 to the 702 and skin. If you haven't done this yet, put a line down the flange of the 702 where there aren't any holes yet and nake sure that line stays in the center of the skin holes while you work on the 404/405/702 alignment and match drilling.

I have a LOT of work to do on my documentation of what I did, but here are a few pictures that may be of help. It is just a rough page I put together out of sequence of what I am working on. link

gsimatos · Post by **gsimatos** » Fri Nov 10, 2006 9:23 pm

Joh and Don, Your info and descriptions have been a big help. I think I got the left side marked and drilled corectly. i am going to try to put some pics in now tho not sure if it will work. First is the famous elevator bearing and the second is my attempt at positioning and drilling ribs 404 and 405....here goes and thanks Gary/Users/garysimatos/Desktop/PB100002.JPG/Users/garysimatos/Desktop/PB100002.JPG

gsimatos · Post by **gsimatos** » Fri Nov 10, 2006 9:27 pm

Sorry you guys, gonna have to rethink how to attach the pics. Just glad to learn how to attach the RIBS!!!! Thanks again for your help G

prestwich · Post by **prestwich** » Sat Nov 11, 2006 2:15 am

gsimatos wrote:How far along are you with your plane??G

Well, uh, I'm on track to beat Spike's two year empennage record! It took me 13 months to build the HS, one month to build the VS, and for the last five months I've mostly been chasing that other variety of tail.

Time to get back to it? Yes, and also to remind myself that it really isn't a race, and that during that first year I was doing a lot of things that many others do before the build: Acquiring tools, learning how to use them, doing the practice kit, setting up my diminutive shop.

gsimatos · Post by **gsimatos** » Sat Nov 11, 2006 3:12 pm

Yeah, ya really need to spend time getting the shop and tool organized. yesterday after working all week in my shadow I decided to hang a flourecent light over the table. got it all hung then the tube dropped out and smashed into a million pieces which took 2 hours to clean up and I still sat on busted glass this morning. Back to the 404-405 rib issue I think I got it all lined up and as you guys noted you sure gotta watch the hole placement to keep them all legal and not too near any edge. The left side is shaping up nicely. does this mean I should have fewer problems with the right side?? Who knows. While I have ya on the phone, how do ya put a photo on this site. Now I gotta a "honey do" list for the rtest of the weekend so no more rv work foro a couple of days Cheers G

Post by **Spike** » Sat Nov 11, 2006 6:31 pm

prestwich wrote: Well, uh, I'm on track to beat Spike's two year empennage record!

Yeah, life gets in the way. I defy you to beat my record though. Dont do it, its not fun. On the other hand, just in case you do beat my record, Ill probably end up with another one for the wing.

prestwich · Post by **prestwich** » Sat Nov 11, 2006 11:19 pm

gsimatos wrote: While I have ya on the phone, how do ya put a photo on this site.

Gary, you have to host the image somewhere online yourself, then post a link to it here. Click the image tag twice, then insert your image URL between the tags. To check to see whether it's working, click the preview button before you click submit!

gsimatos · Post by **gsimatos** » Sat Nov 11, 2006 11:53 pm

Thanks for the info you guys, Cheers Gary

Snap · Post by **Snap** » Fri Nov 17, 2006 4:41 am

There I was today at work on my day off. Working away on the Emp at the same stage as this thinking, now how do I do this????

I even got the Engineer to have a look and he says 'Where are the dimensions for the placement of the 404?' Yep, I did read this but didn't remember it. Now I will remember it. I love you guys. Where would I be without you all?

cjensen · Post by **cjensen** » Fri Nov 17, 2006 9:51 am

Snap wrote:I love you guys. Where would I be without you all?

Probably having a frontal lobotomy with a bottle in front of you!

Glad you figger'd it out!

svanarts · Post by **svanarts** » Fri Nov 17, 2006 3:36 pm

Not bad blokes for Yanks, eh?