Greetings all you aviation types out there!
After much debate, a few false starts, and some gnashing of teeth, I am actually starting to build the real full-scale VP-2. I was looking for the least expensive assembly to get the ball rolling and decided to start with the bulkheads. The firewall bulkhead seemed like as good a place as any to start. There are a some good reasons to start here too, first off it is frequently station 0 for all of the location references and weight and balance data. The firewall is also the forward most airframe structure, and this assembly doesn’t require any “aircraft grade” lumber in its construction.
There are of course other aircraft grade materials needed for the assembly, but they are relatively inexpensive. In this case it is 10 bolts with corresponding nuts and washers. I ordered the bolts, nuts, and washers from Aircraft Spruce on the 29th, and I already have the doug fir. All I need to do is pick up “a good sound piece of (3/4“) D.F. exterior ply”.
With hardware en-route (I expect it this afternoon!), board lumber in hand, and plywood a short drive and a few bucks away, I started studying the fine details of the firewall bulkhead assembly. I have been going over the plans for the bulkhead with a fine-tooth comb looking at every minute detail, arc, and dimension. This bulkhead is solid unlike the forward and aft spar bulkheads or the stern post. The other bulkheads all have doug fir and white pine cores with aviation plywood (1/4” and/or 1/8“) webs. The firewall is a slab of ply with doug fir reinforcing members bolted on the aft starboard and port sides.
A challenge presented itself with the hardware specifications. The bolts were spec’d on the plans, but the washer and nut were not. With a little detective work I found a vague reference in the “General Assembly Procedure” text in the back of the plans set. The only references to the firewall bulkhead don’t say anything about what hardware is going to be used. There is a brief note that lists a few pieces of hardware but it has no references to assemblies so you are left to your own devices to figure it out. I found the reference after looking up hardware in the Aircraft Spruce catalog and figuring it out there. There needs to be an updated, cohesive plans set for newbies without aeronautical engineering degrees. After I take an AutoCAD class or two I think I’ll get on that.
On several occasions I have heard that when building an airplane on your own you should try not to look at the Big Picture too often. Taking the construction one assembly at a time and looking at the Big Picture only when between assemblies to decide what to do next and for interconnectivity issues. I have been scouring over the whole plans book in detail for a while now and I am starting to see the whole as a collection of smaller independent projects.
I can see now why a lot of builders that jump in feet first without a lot of thoughtful review find themselves feeling in over their heads after a while. I can also see how experienced builders can switch from one area of the aircraft to another or have a couple of completely unrelated assemblies going at the same time. It seems that the secret to keeping a project going and making regular and significant progress is that ability to compartmentalize the structure and focus only on the areas that are currently in progress and always have something to work on. Keeping build time for focused building and planning time for the strategic organizing and advance ordering of materials that may take a while to arrive. The whole process is really three distinct jobs. The Project Manager, the Materials Procurement Specialist, and the Builder/Mechanic. For a project to be efficient and run like a well oiled machine a builder has to keep all of those jobs going independently and up to date while keeping it all synchronized.
As the project manager I have been reading the AMT handbooks and scouring the internet for various upgrades/mods for the VP-1/2. Yesterday I found some drawings from builders for things like landing gear mods, break systems, various trim devices, canopies, fairings, and more.
As the Materials Procurement Specialist I think it’s time to head out an buy a piece of 3/4” plywood, that is if I want the Builder/Mechanic to have something to do tomorrow.
Until next time, blue skies and tailwinds!
~FlyBoyJon
ETA: The delivery came from Aircraft Spruce while I was out picking up the plywood so everything is in place for a sawdust party tomorrow.