Category Archives: Planning

Airfoils

Airfoil RibsThe last few days have been a bit of a blur. I am shaking off the last remnants of a frustrating head cold that lingered for way too long. This week was also the first week of an early class at SJCC before my spring semester classes begin on the 31st. With the cold and classes I haven’t gotten much of anything done at the day job and getting into the workshop was near impossible.

As a consolation, I managed to get in a bunch of pseudo-shop time in by working on the airfoil templates. All totaled up I put in 11 hours marking up the templates on contractor’s paper and cutting out the finished templates. It is surprising how much time can be spent on laying out even the smallest airfoil. Over 30 measurements are used to lay out the basic shape, and you still have to round everything out for a smooth form. Science and art in one operation.

The picture above shows all seven of the airfoils laid out on the kitchen floor. On top is the wing with its 58″ chord. Below the wing is the stabilator, and below the stabilator are the five airfoils that are stacked to form the rudder. There will be 30 copies of the wing rib, 8 of the stabilator and only on each of the rudder ribs. There are a total of five variations of wing rib and two variations for the stabilator, but they are all based of the basic forms. I will post more about the jig and duplication process when I get back to the airfoils. For now, since I am feeling much better, I move back to the bulkhead construction portion of the project.

This last week’s diversion to the airfoils is a good example of building flexibility into your project schedule so you are able to take advantage of available time when life strikes.

Until next time, blue skies and tail winds.
~FlyBoyJon

More on the subject of bulkheads

The day job and a clingy head cold have been less than accommodating this last week. That is not to say I have been idle on the project, though.

A day after my last post I got back down into the workshop and was planing on diving in with the rough cut on the firewall bulkhead, then I thought maybe I should get a little further ahead on the parts ordering. The weather has been funky as of late and I wanted to be sure I have small shop work to do that can stretch out over a couple of weeks, so I dug in with building out some parts lists. Sure enough the weather got colder and wetter yesterday and today.

The next part on my build list is the Stern Post. As far as materials go, it is a very simple part. Two pieces of Douglas fir laminated together on the narrow edge to make a wider board, then sandwich the laminate between two pieces of 1/8” plywood. The complicated part is in the beveling and drilling. The biggest concern here as far as the parts is the adhesive for laminating the wood. By far the most recommended adhesive was T-88. On to the order list it went.

The next assemblies in the construction are the spar/strut bulkheads, forward and aft. It really doesn’t make any difference which one I do first. The materials lists for each are very similar, and aside from the lumber and the T-88 for laminating, the only hardware I need is four aluminum bushings for each bulkhead. While that sounds really simple, there was a complication. Well, more of a learning opportunity than a complication.

6061 T6 aluminum Bushing StockThe bushings called out for in the plans are not an item that you buy, they are something you make. You could call up a machine shop and have them made for you, but where’s the fun in that. The plans call for four different sizes of bushing. They are paired two on top and two on bottom for the forward bulkhead and two on top and two on bottom for the aft bulkhead. Between the bulkheads, the bushings on the forward one will be subjected to greater loads than the aft and between the upper and lower bushings, the upper will be subjected to the greatest loads than the lower. Sounds complicated, don’t it?

I posed the the question what if I used the same sized bushing in all eight? on a couple of aviation forums. There were some legitimate questions, for which I had answers. I’m not going to go into all of the finer points, but all boils down to this, there does not appear to be any structural reason for four different sized bushings. In fact, using the largest/strongest bushing in all eight places reduces the aircraft weight rather than add to it. A net benefit I think. Aluminum for bushing stock, added to the parts order.

Parts OrderWhile I was at it I also ordered the bolts that will be going through those bushings. I will still need to order the washers and nuts, but there are some variables with them.

The lumber still needs to be picked up. Fortunately Doug fir and white pine are not hard to come by locally, nor is the plywood I will need for those parts. Once the firewall is roughed out and the bevels cut I will head out and pick up the remaining lumber for the bulkheads.

Sadly I have not made any sawdust so far this week. Hopefully I will be able to get at least one shop day in before turning this week’s time card over.

Until next time, blue skies and tail winds.
~FlyBoyJon

Post Holiday Ramp-Up

PlanningGreetings fellow aeronauts, intrepid adventurers, and aviation enthusiasts,

The holiday season is a busy time of year for just about all of us. With all of those family, friend, and work related events and engagements that need your personal attention, not to mention all of the holiday shopping for food and gifts, its a miracle we get anything else done! And after all of that is over there is still all of the after-holiday sales which have become such a big part of the seasonal consumer madness that seems to afflict us all.

For years now my family and I do our best every holiday season to stay clear of the holiday shopping blitzkrieg as much as possible.  We trying to keep pretty much all of our shopping to a minimum from just before Thanksgiving until after the New Year. One thing I did brave the wilds for was to get over to the home drome and my favorite local pilot supply emporium The Airport Shoppe at Reid Hillview Airport (KRHV) here in San Jose.

Remove Before FlightI have been in need of some reference materials for the hanger bookshelf and over the course of several visits this the month I managed to gather together a few of the important ones. AC-43.13, the 2011 FAR/AMT, the 2011 FAR/AIM, and all three of the aircraft mechanics handbooks, General (FAA-H-8083-30), Powerplant (AC-65.12A), and Airframe (AC-65.15A). I also picked up a new Remove Before Flight key tag, my old one was getting a bit rough around the edges.

Another acquisition over the holiday was a licensed copy of AutoCAD 2011. Autodesk has a great student license program that grants a three year license for several of its products to enrolled students. Now, I don’t have a clue about using CAD software, but I do know I want to reproduce my aircraft plans in a CAD format. With the plans in an editable digital format it will be a lot easier to produce accurate notes and diagrams for any changes that may come up as well as keep track of individual component parts, assemblies, and materials for said parts and assemblies. There are some AutoCAD classes that I can take at SJCC or Evergreen but my class schedule is full for this term so I will have to see if I can get into a summer or fall semester class. Knowing CAD would most defiantly be a boon for my build projects, and it certainly won’t hurt my educational and career goals ether.

Next on the list of things to do is actually getting some materials and start making some sawdust. Depending of how this years tax return works out, I just might be able to make a trip down to Corona in February for a plywood and spruce shopping spree. I just need to scrape together enough materials money to make the seven hour road trip worth while.

Until next time, blue skies and tailwinds!

~FlyBoyJon

Something about lumber

We Can Do ItIv’e spent some time sourcing materials the last two months and I found out a few things; the most important of which is that it is good to look for local suppliers of wood products. Having said that, I am going to be buying my lumber from Aircraft Spruce. “What the what?” you may be thinking, well here’s the thing, I have been poking around for spruce and doug fir as well as marine plywood. The 1/16″ plywood is a flat out no-go any where else locally. The 1/4″ and 1/8″ plywood can be found locally but the quality varies widely as does the price. I thought I had a supplier for a really low price, turns out the quality matched the price.

I had much better results in the Lumber search in that I could find good quality doug fir. The price for it matched or in some cases exceeded the cost of spruce, which I could not find locally, at least not in quantity or quality. So I am back to Aircraft Spruce, not that this is a bad thing mind you. The main reason I was looking to buy locally is I try to do that with everything. Buying locally improves the local economy, and buying from small business helps revitalize the vanishing middle class. At least I can say in this case that I will be buying regionally from a small/mid-sized company. Aircraft Spruce has a store down in southern California, it’s a seven plus hour drive from San Jose, but paying for gas is considerably cheaper than the freight costs having it shipped up to me. I plan on buying stock sizes and milling myself to keep the costs down and ensure ready availability.

Now that I am back to were I was last month as far as the materials quest goes, I am more prepared and knowledgeable in the area of aircraft lumber. I know what I can get and where to get it, as well as what substitutions I can make for specific applications. It looks like the plywood is going to come in just shy of $1,000 (materials and tax). I need to calculate the lumber requirements, that is this weeks project, but I am estimating that to be about $500. I will need a few odds and ends to have on hand, basic airframe materials, so I am planning on a $2,000 trip including the round trip fuel for the van and me. It’ll be a long day but a fun one I am sure.

The only tool I need to look into at this stage is a plainer which I am sure I can find at Harbor Freight in Newark. I also need to make a router table top and several jigs for cutting precisely duplicated wing ribs, all of the materials for this stuff I ether have or can find locally on the cheap. All-in-all I think I am getting really close to making a lot of saw dust.

Until next time, blue skies and tailwinds,
~FlyBoyJon

Keep moving forward!

As you may have guessed, the day job got in the way of my preferred interests making it hard to get anything done on the airplane. But, now I’m back in the shop going over the construction plans trying to decide where to begin. Most builders seemed to start with the empennage. Building the vertical stabilizer and the horizontal stabilizer first. Because of my shop’s space limitations, I’m thinking about starting with the bulkheads; building the firewall bulkhead, forward spar bulkhead, aft spar bulkhead, and lastly the stern post.

VP-2After the bulkheads are built I can do a temporary fit of the cabin, building the seat components and cabin floor structure without permanently affixing them to short, temporary longerons. I can’t build the completed fuselage just yet, there is just nowhere to put it. Next I can move on to wing ribs, horizontal stabilator ribs, and vertical stabilizer ribs. With all of the ribs cut I can go ahead and start building larger assemblies. I should have enough room to easily store the completed vertical stabilizer. Then I can move on to the horizontal stabilator spar and the stabilator itself.

With the empennage components completed I can move on to other assemblies, forwards spars, aft spars, fuel tank, control stick, landing gear and such. By the time I get to this point, I should have access to a larger space for fuselage construction then I can put it all together. At least that is the plan for now.

As I’m sure you figured out by now, because of my space limitations I am looking to build flat components first, then flat and/or small assemblies. This should keep my space requirements to a minimum until absolutely necessary for the fuselage. The longer I can keep the build in a small space the better.

On another subject, I have been reconsidering the model this last week. The paper laminates that I planned on using as plywood substitutes for the 1:4 scale model just don’t provide enough structural support or hold shape well enough for me to consider them viable, especially the two-ply and four-ply laminates. I had thought about purchasing some balsa materials in the proper size but I almost fell over when I saw how expensive balsa wood has gotten. Another problem is the mechanics of milling small pieces of material from Douglas fir. That being said, I have decided to go with the VP-2 rather than the VP-1 and build it as a single place instead of a two-seater. Because I don’t need to compare the airframes, I don’t really need to do the model. If I run into a problem I can always model the assemblies involved if I need a solid reference.

Following the plan outlined above and building the bulkheads first all I should need to put together right now is a materials list for the bulkheads, source it out and figure what my cost are going to be. I already have some of the Douglas fir and I know where to get everything else I need, so this should be little more than an academic exercise, until I start making saw dust anyway. Oooo… sawdust… I am really looking forward to building.

Until next time, blue skies and tailwinds.
~Jon

Starting the 1:4

1:4 MaterialsWell, to start things off this post is a bit late. As I mentioned in a previous post, this time of year is very busy for my wife and I. I did manage to get out and pick up some supplies. A trip to Home Depot yielded some Gorilla Glue for the frame and some Titebond III to make the laminate that I will use as a plywood substitute and thinned a little it should work well as a sealer to replace varnish on the 1:4.

After looking over the wood at HD and finding all of their lumber riddled with knots, I decided to head over to Southern Lumber. Since I was planning to use clear vertical grain Douglas fir for the aircraft build I decided to use DF for the 1:4 as well. I have heard that DF is more difficult to work with so it makes sense to experiment a little with it before buying a bunch for the full size aircraft.

WorkspaceAfter I got home I set up a little workspace at my desk and set up an area for testing the ply material layup. I cleared the space and prepared the surface, laying out some 6 mil sheeting and taping it down to the desk top. After the work surface was ready I started the first piece of the paper laminate by covering a 1′ x 2′ sheet with Titebond III. Once the glue was brushed over the entire sheet I let it set until slightly tacky to the touch, once it was ready I added the second sheet and smoothed it out, making sure any air bubbles had been worked out, you can see these steps in the pictures below.

Later in the day I checked out how things looked. I was not pleased with the results.

let it dry under a little weightmake sure glue is spread out evenly spread the glueAfter all was said and done, the end product was wrinkled, warped and in general undesirable. Thinking back to my days doing some bookbinding I remembered that glued paper products need considerable compression and dry time. I am going to experiment a little more with the laminating process. I still have hope for the it working well as a stand-in for plywood.

Next week I should have time to start the milling. I know what size pieces are included in the spruce kit so I can start with those. Once I have the lumber milled I can get started with the bulkheads. Hopefully I will have figured out the ply stock issue by then.

Till next time, blue skies and tailwinds,
~Jon

N49FB

This week has been a little hectic and next week will without a doubt be tougher. Every year there is a world wide event the Saturday before Halloween called Thrill The World, my wife and I organize the San Jose / Silicon Valley event. As you can imagine with the event coming up on October 23rd we are rather busy getting stuff ready. Our group Grave Mistake has only a couple more dance workshops before Thrill Day. This makes for a crazy day-job schedule to go along with the fun-stuff, and that doesn’t include the aircraft project! While I will be trying to get at least a little done, buying some materials at least, doing some milling at most, this week and next are a bit tight on time.

VP tailI do have something cool to report though. You may remember on September 21st I filed for an N-number with the FAA through there online system. For those that may not know what I am talking about; the N-number is an aircrafts identification number, it is also referred to as the tail number. They said it would take up to three weeks to get the confirmation letter. I put October 13th on my calendar as a follow-up date to check back with the FAA if I had not received my confirmation letter. Being excited about the project, I checked back every so often to see if the FAA had processed my request. The website says that they update the reserved N-number database weekly, so that’s about how often I checked back. The number I submitted kept coming back as available. Until… the 12th of October! I still have not received the written confirmation but the number shows up in the database as being reserved for ME! WOOT!

As you might have guessed by the title of this post and the little addition to the header graphic, oh, and the giant VP tail to the right, my N-number for this project is N49FB Fox-trot Bravo of course for Fly Boy. If I could have gotten Fox-trot Bravo Juliet I would have, but that does not fit in the numbering convention used by the FAA so Fox Bravo it is. I just like the way the short number sounds… niner fox bravo… if just sounds cool to me. Okay, I’m getting a little too AvGeeky even for me now.

On a builders note; I mentioned in the last post about doing some work with composites on my day-job. That is progressing and I have been reading up on the process as time permits. The more I think about it the more I think I will do the cowling myself. I am still not sure about doing the turtle deck. I have seen a number of VP-1 and VP-2 examples with and without the dome called for in the plans. That is way down the line, so I’m not going to burn a whole lot of cycles on it just yet. I also need to see how fast I can re-acquire my old rusty fiberglass skills.

Thats it for now.

Blue skies and tailwinds,
~Jon

Materials

Got out this morning and did another material sourcing run. It didn’t go as well as I had hopped, but that’s okay. I have made some solid decisions on materials and can now start buying what I need for the 1:4 scale project, as well as buying materials for the full scale airplane. Full steam ahead!

Full Scale

First and foremost, I’ve been able to source a majority of wood products locally. However, it looks as though I will have to run with one of the regular aviation suppliers for the 1/16″ plywood. I can find 1/4″ and 1/8″ but that’s as thin as local suppliers carry. 1/4″ AA marine is relatively easy to find, 1/8″ is tougher, 1/16″ is nearly impossible in any grade.

I found a local source for aircraft cables of the mechanical control variety; not electrical, which I suppose would be obvious to anyone who has been reading this blog since I don’t plan on installing an electrical system in the airplane. It looks like Orchard Supply carries aircraft cable as a regular item.

A local supplier for composite materials is TAP Plastics. I had a feeling it wouldn’t be particularly difficult getting some of the composite supplies locally. They don’t have all of the right fabrics, but they do have some. I am not sure about the resin and epoxy they stock, but for the basic materials to work with them, well those they have in spades. I will check out the chemical stuff later when I get to a point that I actually need to think about composites.

1:4 scale

I am rapidly coming to the conclusion that I will need to manufacture the ply products I need. The lumber is readily available, ply products on the other hand… With the full scale ply sizes being 1/4″, 1/8″, and 1/16″ the 1:4 sizes are 1/16″, 1/32″, and 1/64″ respectively. As I said earlier in this post, it is tough if not impossible to find ply this thin anywhere locally. So, I have resigned myself to the arduous task of manufacturing a replacement material.

At this point I think it will be a laminated paper product. Layers of a a heavy water-color paper should do nicely, maybe a 25 sheet pad. With any luck the end product will be moderately stiff ply-board in the appropriate thicknesses. In 1:4 scale a 4’x8′ sheet of plywood is only 1’x2′ so it shouldn’t be difficult to find the paper stock large enough. I was thinking of using Gorilla Glue as the laminating adhesive mainly because it is very strong and you can use water to thin it for spreading a very thin layer evenly across the surfaces of the laminates. I was hoping to avoid this but ya gotta do, what ya gotta do.

Composites

In truth the only composite parts that I would need to build are the engine cowling and the turtle-deck faring which isn’t even a required part, though, I must admit, I am definitely warming up to the idea.

The EAA Chapter 62 meeting I mentioned in the last post got me thinking about composite materials and processes. I haven’t done any fiberglass work in a long time but that is going to change with a day-job project that I recently started. It has some fiberglass work that needs to be done, so I figured I could brush up on those skills and maybe put some of the new techniques into action.

I purchased a book on fiberglass repair and construction to refresh the old gray matter on the subject. It has nothing to do with aviation but it is all about the basic skills for fabrication and repair in the medium. The book was published in 1988 so some things might be a little different or out of date material-wise, but the skills should transfer reasonably well.

Till next time, blue skies and tail winds,
~FlyBoyJon

Aircraft Grade

Greetings Aeronauts,

This week has been interesting. In Monday’s post I talked about getting a copy of the VP-2 plans and the idea of building both the VP-1 and the VP-2 in 1:4 scale to compare the plans. Looks like I will begin working on an airframe sometime next week. I am really looking forward to start actually building. This weekend is jammed with Grave Mistake workshops and the Step Out: Walk to fight diabetes 5k that my wife and I participate in every year along with some friends.

Throughout the week I have been interacting with the great people in the Volksplane Yahoo Group and the fine folks at Oshkosh 365. I got several replies when I asked for some advice on adhesives for wood aircraft. The plans call for Aerolite which does not appear to be readily available. For the most part I got a lot of thumbs up for T-88. Other suggestions included, Aerodux which is a Resorcinol Formaldehyde Adhesive like Cascophen, and West System Epoxy. I am not sure which one I will go with but I am leaning toward the T-88. I need to get the MSDS for each of them as well as take a look at volume, weight, coverage, and relative strength comparisons, and yes, the cost comparison, too.

Another question I had was about Certified Aircraft Grade Lumber. It looks like there ain’t no such animal. In short, your aircraft lumber supplier checks the material to make sure it meets the standards of Aircraft Grade, those standards being MIL-S-6073 Military Specification, Spruce, Aircraft, MIL-P-6070B Military Specification, Plywood and Veneer Aircraft Flat Panel, ANC-18 Design of Wood Aircraft Structures, and of course the standards set in AC-43.13 1B Maintenance & 2B Alterations Aircraft Inspection, Repair & Alterations. They inspect the material, stamp it, and price it accordingly. It is not a federally recognized certification, it is a voluntary compliance to Military Specifications set back when the military used wood aircraft, with a little updating now and then. Don’t take that to mean that I think it’s all hokum; I don’t. The standards are there because they are appropriate to the application. If you are not sure how to grade lumber or are not sure if you can determine compliance reliably, buy lumber from someone who can make those assurances!

While Sitka Spruce is the de facto aircraft lumber, it is not the only species used. The main factor in choosing wood other than structural strength is grain, vertical grain (VG) to be precise. A VG Clear Douglas Fir (DF) is one of the closest quality woods to Sitka Spruce, in fact it is stronger than the spruce in most respects. The drawback with DF is its weight; DF runs about 26% higher in weight than Sitka. In this aircraft, a majority of the structural weight is in the plywood and not the lumber, so the impact on gross weight using DF instead if Sitka should not be that much. Without an electrical system, using minimal instruments, and other weight saving details like single occupant controls, I think the trade-off in favor of structural strength is reasonable, even wise, not to mention that as a Pocket-Change Builder I can’t overlook the cost of DF being significantly lower than Sitka. Having a supplier less than 20 minutes away doesn’t hurt.

Most likely I will end up going with the VP-2 airframe. It is intended for a higher gross weight and a higher useful weight. With two occupants taking up 170 pounds each, that gives me 340 pounds to work with as a single pilot. While I won’t need all of that, I sure as heck am not under 200, nor have I been since 6th grade. I wrestled in the 220 class in Jr High. The extra airframe strength and the VP-2 load capacity provide a significant safety margin over the VP-1 design which is why I am leaning in that direction.

Something fun thing to add to this week was my first EAA Chapter meeting. There are two chapters here in San Jose with a couple of others less than an hour away giving me a lot to chose from as far as finding a good fit. Thursday night was Chapter 62’s monthly meeting. I am not sure if I am going to join 62 yet, but I did have a good time there. The chapter is more of a flying and activities chapter than a building chapter. As it turned out, last night was a great night for me to go to a meeting there because the speaker was Zeke Smith, author of Advanced Composite Techniques.

Zeke demonstrated his process for vacuum forming a leading edge to be used on an an ultralite project. The end product has a thin outer skin and foam strengthening with plenty of room for similarly light ribs. I was amazed at the strength of the leading edge without any support and the incredibly light weight. If I was working on a composite project I would be buying this book right now. I may still get it for this project to use his techniques to form the engine cowling and turtle deck of the VP. That might even give me more weight advantage for the DF…

Only slightly off topic, I can easily see myself building a composite VP-2. In fact I can see some of the layups for Zeke’s vacuum process in my head now. To quote Red Leader Stay on target.

For anyone interested in helping out the FlyBoy, I need to get a print copy of AC-43.13 1B/2B. Contributions to the Pocket-Change Builder’s Fund are always greatly appreciated.

Until next time, blue skies and tailwinds,
~FlyBoyJon

VP-1 or VP-2?

Decisions decisions… I purchased the VP-1 plans set last week and acquired a set of VP-2 plans this weekend, now I have to make a decision between the designs. Which one should I build? I am estimating the VP-2 would cost between 5% and 7% more for the materials. I don’t think there would be much of a difference in the build time. The gross-weight bump and the extra seat are certainly good reasons to lean in the direction of the VP-2, but ultimately the decision needs to be a combination of practicality, mission, and my own comprehension of the plans. If one set of plans proves to be significantly more difficult than the other for some reason, that will affect the decision as well.

Evans Volksplane VP-1The idea of building a scale model before starting construction of the full scale plane had come up in a previous post. Now it looks like that might be the best way to decide between the two designs. If I build both of the aircraft as scale models first, that should give me a better parts list and I could evaluate the difference in material costs more accurately. It will also give me more insight in the build process for both airplanes.

Cost estimates for a 1:4 scale model of the VP-1 came out to about $45. Building two 1:4 scale models should come in less that $60. A question more important than cost is 1:4 or 1:8 scale. The 1:8 scale becomes problematic as the smaller plywood sizes in that scale would have to be balsa wood, which would increase the cost significantly, or be laminated paper stock, adding a lot of time in material fabrication. The idea with doing the models is to decrease the overall time and address problems with fabrication, not create materials and a whole new set of issues. Another problem with the 1:8 scale is hardware. In 1:4 scale I shouldn’t have a problem locating scale hardware.

Evans Volksplane VP-2With 1:4 scale the only real problem is that the product is on the large side. For the VP-1 we are talking about a 6′ wingspan, 4’6″ long, and a 1’3″ wide tail. The tail being the widest part of the structure with the wings detached. The VP-2 has a 6’9″ wingspan, is 4’9¾” long, with a 2′ wide tail. These are some big model airplanes and the only thing they are missing is the engine and maybe the rigging.

In the end I know that building the scale models is going to help save me a lot of time in the long run. I also know that the 1:4 scale makes more sense for dealing with potential build problems. With the models I don’t have to worry about Aircraft Grade materials and I can devote my time to building rather than sourcing. I also think that the models will give me a better estimate of the build process, and allow me to modify my build order and schedule.

It’s hard to say what direction things will take. I have my own ideas about the build process, when things will happen, how they will happen and all of that. No matter how much I plan, since I haven’t done this before, I just don’t know the path things will take.

Till next time, blue skies and tail winds,
~FlyBoyJon