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fuselage before wing

edward7048

Well Known Member
Has anyone built the fuselage kit before the wing kit if so how
did you handle filing the F-1203C stub spar receptacle and the F-1206C
rear spar receptacle to fit the spars after the side skins were installed?
 
I did (am). I handled that by taking the parts over to a different RV-12 across town and testing the fit. They fit perfectly and no trimming was needed. I ran the edges around the Scotchbrite wheel anyway to smooth them out. I anticipate no problems when joining with my wing. I'm betting that these parts are cut to a fairly high tolerance.
 
I did (am). I handled that by taking the parts over to a different RV-12 across town and testing the fit. They fit perfectly and no trimming was needed. I ran the edges around the Scotchbrite wheel anyway to smooth them out. I anticipate no problems when joining with my wing. I'm betting that these parts are cut to a fairly high tolerance.

It seems ironic to me that your name is Gamble, and that you are betting the parts are made to a fairly high tolerance... :eek:

The construction manual suggests the specific construction order for a reason. Checking on a different set of wings shows that you might be ok, but there is a potential for yours to not be the same.
The odds may be in your favor but you are betting just the same.
A few builders have pre-purchased the needed wing parts and done the check that way.

Personally I don't see understand the rational for deviating from the recommended build order... there is a significant jump in complexity between the wings and the fuselage. I think building the wings first helps prepare you for that.

YMMV
 
a great suggestion

It seems ironic to me that your name is Gamble, and that you are betting
Let's not get personal.
A few builders have pre-purchased the needed wing parts and done the check that way.
That is a great suggestion. A list of parts needed to build the fuselage first would be helpful to builders who want that option. For some builders, it is impractical to build the wings first because it will take them years to build the RV-12 and they do not have a place to store wings that is safe from mice and scrap metal thieves. And some builders are lucky their wives let them build in the living room. Storing wings in the dining room would be asking too much. LOL
Joe
 
For some builders, it is impractical to build the wings first because it will take them years to build the RV-12 and they do not have a place to store wings that is safe from mice and scrap metal thieves. And some builders are lucky their wives let them build in the living room. Storing wings in the dining room would be asking too much. LOL
Joe

Since the wings or fuselage will have to be stored for a period of time regardless which is built first, the wings are much easier to store than the fuselage is. They can be sling mounted close to a ceiling, hung on a wall, etc.
 
Devils advocate here!

Since the wings or fuselage will have to be stored for a period of time regardless which is built first, the wings are much easier to store than the fuselage is. They can be sling mounted close to a ceiling, hung on a wall, etc.

You can't sit in the wings and make airplane noises while building the fuselage!
 
Let's not get personal.

I wasn't meaning it that way....really.
I truly meant I saw irony in it.
A company designs a kit and produces what might be one of the most extensively developed construction manuals ever done, and builders decide that certain key points in the build process are not important.
I understand that it probably comes from one or two builders saying they did it and didn't have any problems. After many years in this business, I have learned that this doesn't always mean much. Some problems are not recognized because builders are not aware of all of the possible issues.

Example - a current thread about exhaust system interference with the cooling duct. It is entirely possible (not saying it is the cause, just possible) that the interference is the result of installing the cowl with a generous clearance to the prop spinner. This would have an effect on how far aft the cooling duct ends up being, with teh resulting posibility of interfearance with the exhaust.

There are lots of RV's that are flying around with problems and the builders/owners don't even know it. Reading one or two posts on VAF about something working OK is not a strong assurance that it is (I know this wont offend Doug, he is fully aware of this already)

I have now been directly involved with the construction of 3 RV-12 fuselages. Adjustments were made to said parts on all three. Some of them would have worked had nothing been done but they would not have fit as well as they could have otherwise. The fit of a couple of the parts probably would have caused wing install/removal issues.

So, I will add my suggestion to the pool of opinions.... With what I have seen regarding building RV-12 fuselages, this is not a gamble I would take. Even if parts fit great on someone else's wings, doesn't mean they will fit well on yours.
 
Joe Dallas Building the wing last

Vans engineers have designed a lot of great airplanes.
The EAA has many types of builders, some like to build and let some one else do the thinking.
The builders that think out of the box add to the advancement of the design, some good and some not so good.
For me I like the designing as much as the building and will have a hard time following the plans if I think there is a better way to do it ( any change will be well thought out )

I read all the posts on the RV10 and RV12 Sites to see what other builders have done and try to learn.

For me building the wing last makes a lot of sense.
I called vans and we talked about this before ordering my first kit.

I think the main Question! How
did you handle filing the F-1203C stub spar receptacle and the F-1206C and did it fit the first time is a good question.
Builders Answering this question will be a great Help.
Joe Dallas
www.joesrv12.com
 
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I was half tempted to not even answer the original question, knowing full well what the result would be. I'm just sharing an experience here, not advice.

It seems ironic to me that your name is Gamble, and that you are betting the parts are made to a fairly high tolerance... :eek:
I have the wing parts now and they fit fine. No one is more relieved than I am!

Don't worry about the irony of my name being taken personally - trust me (and anyone else that has a verb or a noun in their name), I'm used to it. You should hear the response in Vegas! :)

The construction manual suggests the specific construction order for a reason.
While this particular case is an admittedly imperfect example, I'd have to take off my shoes in order to count the number of times that following the specific order suggested in the manual will result in nothing but frustration. Having just spent the better half of a Saturday on page 28-06, Step 1, I find myself wishing that I had done that one a little out of order. Somewhere in Section 22, I think.

I'm also pretty happy to have deferred all of section 23 until after sections 27 and 28. I understand that the manual is broken down so as to keep distinct systems all in one place, but that's not really how the airplane is best built. That's not to say that it's wrong to have the precise order laid out the most logical way; I'm just saying that the lost logical isn't always the most efficient. But you're right in saying that there is a huge difference between installing a bulkhead fitting out of order and changing the order of entire kits.

In my personal situation, what I build and when I build it is a balance between weather and location. I opted for the fuselage first because it is small enough to do in the preferred location. The wings will have to be done in my hangar, and that is a spring/fall project.

I probably would have decided differently if there was a brief note on the order form stating that the fuselage kit requires parts of the wing kit to be completed. Something as simple as that would go a long way towards helping others decide; the fact that the question was even asked here indicates that I am not the only one that got it wrong.
 
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While this particular case is an admittedly imperfect example, I'd have to take off my shoes in order to count the number of times that following the specific order suggested in the manual will result in nothing but frustration.

I never meant to imply that the RV-12 construction manual was perfect. It has been evolving because of input from early builders. In this instance, it isn't changing from a problem with the construction flow. It was choosing to skip a specific step, not defer it until later or do it in a differen t way.

I'm also pretty happy to have deferred all of section 23 until after sections 27 and 28. I understand that the manual is broken down so as to keep distinct systems all in one place, but that's not really how the airplane is best built. That's not to say that it's wrong to have the precise order laid out the most logical way; I'm just saying that the lost logical isn't always the most efficient. But you're right in saying that there is a huge difference between installing a bulkhead fitting out of order and changing the order of entire kits.


I never meant to imply that the order couldn't/shouldn't be switched around. Only pointing out that disregarding a specific instruction to do a fit check between critical parts that come in two different kits is not a good way to build an airplane. "Hoping that it fits", on parts that will be extremely difficult to change later, concerns me. Other than that, yes, lots of things could be done in a different order with proper planning.
 
Wing Last

What would you do if you bent up a wing and have to build a new one

Lets try to find a way to make this work for the guys that want to built the fuse first

Thanks
Joe Dallas
www.joesrv12.com
 
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The real issue

The build order can be varied from the plans although doing so might make some steps more difficult. Conversely, changing the build order can make some steps easier. The important thing is to follow the plans and do each step as instructed, whether it is done in order or postponed to some time in the future. Following the plans will ensure a safe aircraft without getting hit by "shooting arrows". :D
When my plane is completed, I will go back through the plans, step by step, to be sure that everything is completed as directed.
Joe
 
What would you do if you bent up a wing and have to build a new one

Lets try to find a way to make this work for the guys that want to built the fuse first

Thanks
Joe Dallas
www.joesrv12.com
I think if you had to build a new wing, you would be in the same situation. If the new parts didn't fit, it seems that your choices would be to either also replace the matching parts in the fuselage, find a way to shape the parts in the fuselage from outside the slot, or file a few millimeters from the spar tab. The best case would be that the damaged wing was not damaged at those tabs so you'd be able to re-use the originals.
 
One possible solution

I think if you had to build a new wing, you would be in the same situation. If the new parts didn't fit, it seems that your choices would be to either also replace the matching parts in the fuselage, find a way to shape the parts in the fuselage from outside the slot, or file a few millimeters from the spar tab. The best case would be that the damaged wing was not damaged at those tabs so you'd be able to re-use the originals.

Thanks for your constructive replay

I will build the Fuse first and possibly two sets of wings

One set per plans.


And one with Fuel Tanks in the wings.
Im still working on the design of the fuel tanks and will built them if the Numbers all work out

I will make templates of the F-1206C & F-1203C Stub Spar Receptacles and match the wings to them.

One possible solution

Joe Dallas

www.joesrv12.com
 
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Order two sets of spar stubs

I will make templates of the F-1206C & F-1203C Stub Spar Receptacles and match the wings to them.
joedallas,
Order an extra set of spar stubs along with the first set of wings. You can make sure that both sets are identical. No templates and no worries.
Joe
 
second possible soiution

joedallas,
Order an extra set of spar stubs along with the first set of wings. You can make sure that both sets are identical. No templates and no worries.
Joe

Mitch I think you ment with fuse not wings.
That should work.

I will order two sets of the F-1206C & F-1203C Stub Spar Receptacles with the fuse, match them and use the second set to match all wings.

Thanks Mitch
Joe Dallas
www.joesrv12.com
 
Mitch I think you ment with fuse not wings.
That should work.

I will order two sets of the F-1206C & F-1203C Stub Spar Receptacles with the fuse, match them and use the second set to match all wings.

Thanks Mitch
Joe Dallas
www.joesrv12.com
Here's are the wing parts you would need if you wanted to do the fuselage first:

(2) W-1207B REAR SPAR DBLER.PLATE $11.30
(2) W-1208B STUB SPAR DOUBLER $4.15
(1) W-1208C-L STUB SPAR CHANNEL $20.60
(1) W-1208C-R STUB SPAR CHANNEL $20.60

The 1208Bs get riveted to the 1208Cs to create the full thickness of the front spar stubs. The 1207B-s are already full thickness. With these parts you can determine if you need to do anything to get the matching fuselage parts to fit correctly. You can match the parts that come later with your wing kit to these and set them aside as spares.
 
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Two sets of males and one set of females

I think you ment with fuse not wings.
No, I meant to order two sets of the wing male spar stubs and one set of F-1206C & F-1203C Stub Spar Receptacles for the fuselage. Then you will be sure that both sets of wings will fit perfectly into the fuselage and you will be following the plans exactly. (Except for putting fuel tanks in the wings) :D Matching parts against templates or other parts not actually on your airplane is what prompted Scott's original posting above. If you end up with an extra set of wing spar stubs, Van's might even take them back if within one year of purchase. The plans have you shape the receptacles, not the wing stubs. If you shape the receptacles for the first set of wings, the second set of wing spar stubs purchased at a later date might be too small or too big. If too big, you could file them down to fit, although that is not what the plans say to do. But if the new wing spar stubs are too small, how will you make them bigger? These parts should fit with close tolerance to prevent the wing from rotating. You need to be able to hold the parts together and view them from the side to make sure that they fit like a glove around the entire circumference.
Hope that helps.
My user name, Mich48041, is where I live, in Michigan. My name is actually Joe, like yours.
 
This will work (Thanks All )

I will order two sets of the wing male spar stubs and Two sets of F-1206C & F-1203C Stub Spar Receptacles for the fuselage

That way I have both ways covrved.

Thanks Joe from Michigan

Joe Dallas from Florida

www.joesrv12.com
 
Ok, so I think I've convinced myself that I've got this right, but want to double check before filing away...

I believe the parts are in their correct orientation in the top part of the pic below, correct? (It just gave me pause that at first glance they seem to fit better the other way around, at the bottom of the pic.)

XTHKWqll.jpg


Next, is how to determine the relative angle between the two... I'm thinking the small flat on the inside bottom radius of the F-1206C receptacle should be co-linear with the bottom of the stub spar assembly? Makes sense from a gravity on the ground standpoint, when installing the wings, but under loading they'd want to go the other way, so just want to be sure.

S0mSrQRl.jpg
 
Small Flat

The orientation of the small flat is in the plans. Unless I?m missing something what?s the issue?
 
Looking at the plans, I think I see what the problem is. The parts on the left are the W-1208B stub spar doubler and W—1208C stub spar channel. The part on the right is the F-1206C rear spar receptacle.

The stub spars attach to the F-1203C stub spar receptacles, not the F-1206C rear spar receptacles. See drawing 21iS/U 13 for F-1203C. It has a bevel to indicate the top of the part. The W-1207B rear spar doubler plates attach to the F-1206C receptacles.

Drawing 21iS/U-01 provides a good overview of both receptacles in relation to the entire mid-fuselage assembly.
 
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Looking at the plans, I think I see what the problem is. The parts on the left are the W-1208B stub spar doubler and W?1208C stub spar channel. The part on the right is the F-1206C rear spar receptacle.

The stub spars attach to the F-1203C stub spar receptacles, not the F-1206C rear spar receptacles. See drawing 21iS/U 13 for F-1203C. It has a bevel to indicate the top of the part. The W-1207B rear spar doubler plates attach to the F-1206C receptacles.

Drawing 21iS/U-01 provides a good overview of both receptacles in relation to the entire mid-fuselage assembly.

YES! That's it, thank you!! Lol

The plans say, Step 8: File the rear stub spar rounded ends of both wings..."

I focused on the "stub" part, so I went for the "stub spar assembly." Plans could be clearer here, but perhaps if I had built the wings first it would have been more obvious? Oh well, all good now.
 
Now that I think I've got the right parts, the rotation question remains...

The spars don't appear to have a top and bottom at this point, but they can still rotate within the receptacle.

So do I file the spars to fit orientation A or orientation B? (I think it's A, but you can see they already fit quite nicely in B, so I don't want to screw it up)

aoa0xUFl.jpg
 
Now that I think I've got the right parts, the rotation question remains...do I file the spars to fit orientation A or orientation B?

That's the part of your original question I was wondering about, too. If you don't get an answer in the forum, let us know what you learn from the factory.
 
That's the part of your original question I was wondering about, too. If you don't get an answer in the forum, let us know what you learn from the factory.

Response from Van's:
The angle at which these two interface is predetermined by their relative positions/orientations in the airframe. Your positioning ?B? look better but is probably turned a little too much and should come back a little.

I basically split the difference and it ends up fitting through a good portion of the rotation.
 
Well, after reading this recently revived old thread: https://vansairforce.net/community/showthread.php?t=47846, I am once again concerned/unsure about the filing of the stub spars.

Specifically this exchange [Text in brackets are mine]:
In this case, the manual does not say to file on the stub spars if/as needed. [When attaching/fitting the completed wing for the first time]
The only time the manual says to do any filing on these parts is during [fuselage] construction. Even then, it says to do only enough to get a close fit between the parts so that they fully mate together.
Scott, Beg to differ a bit. The general instructions, tell you to remove the machining marks/nubs from the parts to eliminate any stresses. In this case, that is all I did. Yet still needed a small shim.
Maybe in this case, a special instruction in the plans is needed to ensure the builder removes ZERO material from these areas. When I fitted the parts per the plans, they fit just fine. Now I realize, a loose fit here would NOT be detected.

The step says: "File the rear stub spar rounded ends of both wings to closely fit the recessed machined curve of the F-1206C."
I didn't file away extra material all will-nilly, but I was focused on getting the best "closely-fit" I could get, because there was no other guidance given.
The instructions do not stress the importance of removing only the absolute bare minimum necessary.

It's been a while since I did this step, so I can't really say how much I removed, but based on Marty's experience it sounds like any filing here could be too much?

Something else in that thread prompted me to go look at the maintenance manual, which has this to say about the Condition Inspection: "If the W-1207B rear spar doubler has been trimmed too much, the finished airplane may exhibit some play at the rear spar junction. This is usually discovered by hearing a “click” and detecting in/out movement when the wing is installed. Increasing the length of the spar doubler is not possible, so it must be removed and replaced with a different, slightly longer, part."

If this fit is indeed so delicate, then I agree with Marty, it should have been stressed in the KAI.
The other thing here is that there is no mention of using a shim, just says must remove and replace?

I haven't built the wings yet, so I guess I'll just order another set of rear spar stub-doublers, either to just compare my filed parts to, or maybe just toss the old and use the new, being extremely careful during deburring. Thoughts?

And lastly, what about the forward stub, where you are supposed to file the recessed socket to "closely fit" the stub? Is that connection just as finicky?

...Or am I massively overthinking this and should just finish the *&^%! build and then shim if needed? :rolleyes:
 
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