'Assisted Scratch' from plans?

[davecove]

Let's say a guy ordered a RV-9A plans/manual CD and printed the plans 1:1 from the PDFs with the intention to scratch build most of the plane. Is building from the CD plans/manual allowed by Vans?

Let's also say that the guy found 10% of the parts too much trouble to fabricate himself. Would Vans sell him those parts outside of a kit (a la carte)?

Sort of an 'assisted scratch' approach.

[Mike S]

Dave, welcome to VAF

As for your questions----------a number of Vans employees are on this thread, I suspect you may get an answer from them.

Or, you could just call the factory and ask.

Sounds like you have a rather ambitious project ahead.

[davecove]

Somewhat ambitions... I am a computer/electronics nut besides being a pilot and am about 60% of the way finished with a 4'x8' CNC router table that would make the cutting/shaping of pieces and forms a whole lot faster than the traditional scratch method using snips.

What I am wanting to do is fabricate all of the 'flat' pieces myself and buy the more complicated bits from VANs.

[David Paule]

I am not building an RV-9 and don't have a set of those plans, but I seriously doubt that they provide anything like enough information to scratch-build the plane.

Basic things like the lengths of parts and the thicknesses of the materials isn't shown on the RV-7 or -8 plans, because the kit comes with those parts. You might be able to get sort of close, but I really doubt it. Since the kit is pre-punched, hole spacing probably isn't in the plans.

I'm building an RV-3B and that's plenty challenging enough. It has per-made parts and actual plans that are almost enough to scratch-build it and it's still a real project.

Dave

[BillL]

Sadly, if the 9 plans are like the 7, then they are completely inadequate to be used to scratch build an airplane. Dimensions, angles etc are needed to make the parts. Definition of materials and thicknesses are also incomplete. The plans, as provided, serve very well to assemble an airplane, and with sufficient dimensions to fabricate a few of the parts. It is my understanding that plans exist for the RV6 to do what you are wanting.

Is there some reason you don't just get the kit and then make any of the fabricated parts needed by your proposed processes? You would get a proven design and a taste of manufacturing.

[davecove]

make any of the fabricated parts needed

Can you add some detail to that? Not being a Vans builder (yet) I am not familiar with how (in)complete the kits are.

It is my understanding that plans exist for the RV6 to do what you are wanting.

From Vans? or from folks who bought a set and never used them?

[DaleB]

As noted by others, the plans are not adequate for making most of the parts. They show the shape and layout but not dimensions, thickness, etc. For example... look at the plans on CD. Pick any outer skin at random. Now figure out how you'd cut it to size, let alone plot the hole locations for CNC punching or drilling.

If I were designing an airplane to scratch build, the Van's plan drawings would be extremely helpful to see how it's done well. And of course they are pretty good for assembling one of their kits. That, however, is about as far as it goes. As for them selling you parts, I don't know. I've heard mixed reports from non-RV builders trying to buy parts.

As for CNC fabricating the parts Van's doesn't supply pre-made... there are some that you make yourself, often from angle stock. Cut, trim, drill. I suppose you could CNC them, but I have a CNC router and I have yet to see a part I couldn't make several times over in the time it would take to draw it up in CAD, generate a toolpath, and ruin one or two on the CNC machine until I got it right. The band saw and rill press aren't nearly as precise but they're a lot faster.

[davecove]

Dale, point well taken... I had planned to CNC only the sheet stock and maybe some of the formers, not the 'solid' parts.

[Vern]

I think you get many more 'specs' on the old hand drawn plans. The newer plans are basically an assembly diagram vs the old ones which gave many dimensions, which would work for your purposes provided legal hurdles are dealt with.

I built my RV-6A without any kits from Vans. I used leftovers, crash parts, abandoned parts, etc and a lot of creativity. There was an article on it in Vans newsletters years ago. It was a ton of work.

[DaleB]

Originally Posted by davecove

Dale, point well taken... I had planned to CNC only the sheet stock and maybe some of the formers, not the 'solid' parts.

Yeah, those (sheet stock, bulkheads, ribs) are exactly the ones that would prove most difficult given the available (lack of) data.