Here I am! (Waving)

No, over here!

And there I am, suddenly back from Google's mysterious glitch. No explanation of course. But I poke my screen-name & password into the hole in the hollow tree, just the way I've been doing it for however long it has been. And suddenly there I am! The magic mirror is working again. Captain Midnight's De-Coder Ring whirls into action and all your Secret Messages come tumbling from the chute. Yes, you may use rocker arms of different lengths in the same engine. Then a pile of questions for which I don't know the answer... and tell them so. And another pile of airplane questions, most of which will take some time to answer correctly because I no longer trust my personal Memory Bank since my stroke and flying is one hobby that can get you killed.

Kinda like being knocked off the Internet.

Which produced a new email address for me: veeduber@chuggers.net

Yeah, it costs money. But the money buys you names and telephone numbers of people you can call when the system goes suddenly klunk! in the night and leaves you with nothing but a blinking cursor and a beige box that blows warm air on your shoe.

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I have a new hole in my back. It was put there on purpose by a Jason M. Miller, a physician who specializes in Pain Management. That is, in reducing it if you've got some, of which I do.

The hole was made by a tool the size of a knitting needle into my Epidural Space, which I understand is a fluid-filled void around the spinal column. The purpose of the hole was to inject Narcotics and Steroids into that space, causing the nerves which run through it to stop carrying their Pain Signals.

So howz it working out? Eh... sorta same-old same-old. But better, I think. The Killer Spasms haven't shown themselves but they are so painful that I'm afraid to risk their ire by saying they are gone for good.

There is still a limit to how long I can stand up and walk around. But the pain engendered by that activity is definitely less. It is still too painful to push it; when the Pain arrives I've got to sit down or I will soon find myself on my hand & knees. But the pain occurs lower down than before. And its intensity is definitely less. So I think it's fair to say that some Progress has been made.

Is this topic of any interest? It is to me, since the Pain is like a prison sentence. Were it not for the Pain I would be doing more things in the shop. But it may be of no interest to you. As it now stands the Pain is my excuse and explanation for not doing a lot of things I was doing before; things I shared with many of you and which I know you were interested in.

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Have you read 'The Ugliest Toolbox'?

It is the first article I uploaded when I created this blog. Somewhere in this blog are the illustrations showing how to cut & drill the pieces of metal which, when riveted together, become a clunky but serviceable toolbox, large enough to hold a tin-benders basic kit of tools. The late Jim Holland and I are guilty of showing local Boy Scouts how to make the toolbox, which was a bit of a scam since what we wanted to teach them was basic sheet-metal work, including riveting. And we did, for a couple of years back when I was still in the Navy.

I mention it here because there were two groups of guys making toolboxes when Google pulled my plug. I eventually got re-connected but a strange thing happened to one of the groups. They decided the toolbox was too basic and stopped working on them, which kinda reminded me of the Ugliest Toolbox.

I suppose there are such things that are too simple to justify our attention but the most valuable lesson contained in the Ugliest Toolbox is how to build an airplane, a house or anything else. And if that sounds impossible, it's not.

Wanna know the best kept secret of the ages? Wanna know how you can build your own airplane? Well... okay, I'll tell ya. But you got to promise to keep it a secret.

Here it is: Do something every day. That is, something leading toward the completion of whatever it is you're trying to do, such as building a house, overhauling an antique car, building an airplane from scratch... It doesn't matter what you're building. Or rather, trying to build. The secret of success is to do something every single day. It doesn't matter what it is... drilling a single hole, setting a single rivet or whatever, what matters is that you Do It! Every day. No exceptions nor excuses.

Here's why it works: Every project has a finite number of steps. If you do even one of those steps every day you will eventually run out of things to do; the project will be finished.

No, you can't make bargains with yourself, such as promising to do five things next Saturday instead of one thing every night for the coming week. That's not allowed. You have to do something every single day.

What you're doing here is developing the habit of doing something every day.

Yeah, it sounds kinda wacky. But it works.

-R.S.Hoover

BOB HOOVER... LIVE!

To All:

That's meant to be a kind of joke, see... because I have cancer I'm never too sure I'll wake up in the morning so I thought labeling a post as 'Live' would be something of a play on words.

But the title also emphasizes an on-going problem I'm having with Google and my memory, in that I often forget my User Name and Password, making it impossible for me to either SEND or RECEIVE messages. This morning for example, Google says my current User Names and Passwords will no longer be valid; that I will have to jump through various Google-hoops to make things right. But when you try to do that you get an ERROR MESSAGE saying to try again in a few minutes. The Mystery Time is not defined. Five minutes? No, that's not enough. Ten minutes? Ditto. Indeed, it appears that Google's error-handling procedure may well have an error of its own, in that, while it SAYS to do this and go there, it doesn't actually work. If the problem persists you're told to contact yet another address. Which of course does not work either.

But I am still alive! Honest! And people still send me email asking questions about their VW engines, converted for flight or otherwise. And I keep trying to respond because I assume you would like to receive an answer. But given the amount of errors, trying to stay in touch becomes horribly frustrating.

-R.S.Hoover

The Chugger

The above is a sketch of 'Chugger,' a minimum cost design meant to be fabricated using wood from the typical lumber yard. The engine is a Volkswagen, converted to put the propeller on the flywheel end of the crankshaft, where it will be immediately adjacent to the thrust bearing.

In American slang a 'chugger' is a person or machine that isn't very sophisticated yet manages to get the job done.

The minimum cost aspect of the design is achieved by using lumber that is locally available. This point keeps popping up, despite the fact the Government has not been in the business of grading wood since the 1950's. What you get when you buy 'aviation-grade' lumber is a piece of wood that has been graded by someone at the saw-mill. Or at the retailers. It will be nice, clear lumber, graded according to those standards of long ago but you won't find a government stamp on it. Most of it will be Sitka Spruce unless you have asked for something different, such as Douglas Fir or perhaps Northern White Pine. (The government inspection criteria covered more than two-dozen species of softwoods commonly used in the structure of lightplanes.)

I continue to receive more messages on this aspect of Chugger's construction than all others combined. I've nothing against the use of certified materials. For example, I still want you to use aviation-grade plywood, although not very much of it.

In recent weeks several prospective builders have swished past the earlier version of the drawings, some are even willing to fly it to the various fly-ins... if I'll give them a flyable copy of Chugger to keep as their own. I take that to mean they've found nothing fatally flawed in the design.

Except for the use of Blog Store lumber.

I think everyone is wrong in that regard and I believe I can prove it.

If you will click on the opening drawing it will expand to fill your screen. The firewall is 24" in height which should allow you to get a rough estimation of the length of the remaining sticks(*).

I will agree that it is difficult to find aviation-grade lumber long enough for spar caps or longerons but the drawing makes it clear that most of the required pieces are quite short. You will have no trouble finding sticks of that size by simply ripping a 2x4 or even a furring strip. Indeed, here in Southern California the decline of our economy has left the lumber department of most blog stores as empty as the Kalahari.. This aspect of wood-quality is equally true for the wing. The point here is that aviation-quality wood is available from local lumber yards. The only tricky part is that you must spend some time grading it.

The common myth that wooden airplanes are made entirely of wood is simply not true. Indeed, many potential builders prefer aluminum or rag & tube because such airframes require fewer tools and far fewer skills.

The second drawing, which should be wandering about near this paragraph is meant to serve two purposes, the first of which is to give the reader some idea as to the number and location of the metal fittings. The idea here is build this much of the fuselage as mock-up for the fitting & welding of the metal fixtures for such things as the landing gear, the wing-strut attach points, and the cabanes. Not shown are the Cub-type landing gear Vee, the control stick and the rudder pedals. These were not shown partly because I forgot to put them in but also because they are so simple they are easy to forget.


As the Chugger's drawngs are developed they are being posted in the Chuggers-alt Group. But nothing is in its final form. As I've said in the Introduction, the Files represent a series of experiments, conducted for the purpose of proving or disproving the practicality of building an airplane that draws most of its materials from local sources.

If you find the Chugger of interest please have the courtesy to read the Introduction.

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(*) The lumber carried by the Box Stores usually has too many knots to pass the old government standards in lengths of twelve feet or more. But it's not uncommon to find a knotty 2x6 that passes -- or even surpasses -- the old certification specs. Unfortunaely, the longest peice without a knot is only six feet or so.

If you find a stick like that, grab it! After you have re-sawn the stick into 3/4" by 1" sticks, even though it is liable to break at the knot you are still left with two perfectly good pieces! Indeed, if you'll examine the top drawing you will see that the longerons are quite short. While it may be necessary to scarf some pieces together to obtain the needed length, by building the splice right in to the design I should be able to find pieces of the required length without having to re-saw very many pieces.

-R.S.Hoover

Harvesting Data

Most guys call it blueprinting. You measure the part then check the measurement against the 'blueprint.' Which hasn't been a real blueprint since the 1930's. Nowadays it's just a file of dimensions and tolerances provided by the manufacturer, usually in their Factory Service Manual. Alas, the task isn't as simple as it seems. In many cases the factory manual cites only metric dimensions, leaving the conversion up to you. In other cases they cite both Metric and English units of measurement... and sometimes gets them wrong, requiring you to keep on your toes when they say one millimeter equals 0.3937" ...when they should have said 0.03937".

An even trickier bit is what happens when you depart from those stock dimensions. When you build a big-bore stroker you are literally designing a new engine. Cutting the heads to accept larger jugs requires you to measure the diameter of your new jugs and then add the anticipated thermal expansion to that dimension, and finally to add some small amount for your tooling wear.

This sort of thing -- the designing of a new engine -- is largely a desk job. No greasy fingernails. And yes, your computer comes in very handy. Not so much for the computation of things but simply for storing them, ideally with drawings.

So where do you come up with those figures that are not listed? Standard engineering manuals, such as Machinery's Handbook will give you the accepted standards for the thermal expansion of your parts but the particular alloy plays a role I'll mention in a moment.

Thermal expansion takes place in all three dimensions. The engineering manuals say that the intra-molecular space will INCREASE as the temperature of the part increases. Some call these dimensions -- the ones not listed for our particular engine -- the experience factor when in fact we've simply memorized the values of interest from tables found in various manuals. Pratt-Whitney and Machinery's Handbook sez 0.003" per inch for cast iron and .007" for cast aluminum... which works well enough for the alloys used by VW in their heads and barrels.

But if you don't know what alloy is being used, you'll be safer if you put the part(s) in an oven and raise them to their anticipated normal temperature. And learn to measure them quick like a bunny, before they can cool off and before they can heat-up your micrometer. That's enough to give you some idea of the problem, which is the fact your heads and barrels will expand at different rates.

Not everyone does it that way. In fact, a lot of 'experts' don't blueprint anything. Their engines usually end up in dune buggies but there's a few who build engines for airplanes. In doing so they follow the same procedures -- and use the same tolerances -- they have used for dune buggies. This entails considerable risk because there are significant differences between the VW engine in a vehicle and one that has been converted for flight. The most evident of these differences is the higher temperatures experienced in engines converted for flight. This higher temperature reflects the fact that a flying Volkswagen is operating at a continuous level of output at least fifty percent greater than that found in any vehicular engine.

The builders of dune insist there is no difference between their engines and those used for flight and that is substantially correct. But there is a profound difference in how the engine is USED and that is easily illustrated by the fact an airplane must sustain itself in the air. To do so demands a higher level of output on a continuous basis.

-R.S.Hoover

The Follower Phenom

Uh-oh. What's this?

In the military one of the targets used on the pistol range was a silhouette of the upper torso. To maintain our proficiency with handguns we would periodically go down to the Pistol Range and shoot holes in those Silhouette Targets. Now Google is putting silhouette targets on one of the pages supporting my Blog. Pistol target with 'Followers' underneath.

Little green Silhouette Targets on the Dashboard page, which I've not visited since... whatever. I dig around here & there... I haven't had much luck as a blogger. For example, I didn't know they paid you for blogging! I'm still not too clear on how it works. Sometimes Google sends me money. And sometimes they don't. After a while they apologize for not sending anything, promise to do better. And don't.

Then there are the things they simply whip outta thin air, full-grown, which they apparently expect me to be fully aware of, when in fact I'm barely aware of them, let alone the weird stuff they are continually creating, apparently having mistaken activity for progress. Like this 'Follower' business. I dig around trying to find out what this latest phenom entails but come up dry.

Surely 'Follower' doesn't actually mean Follower! Because if it did, it would mean I have been promoted to Fearless Leader... like that guy in N. Korea with the bad comb-over. Is that how people see me? As a Nutsy Cookoo? Trouble is, the Korean Cookoo is desperately eager to be a Fearless Leader and I am not. So which is it?

Click the icon and sure enough, a page pops up with a list of people. I recognize a couple of the names but others are complete strangers. Which worries me even more. I'm happy to meet these people; happy they've found something useful in the material I've posted. But to me follower implies leader and that's the part that worries me. Is there something I should be doing to fulfill my new role?

I've tried to find more information about Followers but the only meaningful thing I've heard is that it's people who want to maintain closer ties to me. If that's the case, my email address is veeduber@chuggers.net.

However, if the 'closer ties' means telephone numbers and that sort of thing, when someone calls I generally can't get to the telephone before the ringer times out and the pre-recorded voice tells them to leave a message. I've got a cell phone but I don't know my number. The cell phone was a gift from my wife when I became ill. But I don't use it very often.

When my sister was ill I was expecting her to return my call. When the phone rang I tried running, hoping to catch it before it timed out. Bad idea. I managed to trip myself up and took a bit of a fall. Scared the hell out of my wife and made me feel like an idiot.

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So... welcome, all you Followers. As your Leader I'm not too sure what my duties are but I'll try to do my best.

Right now I've been studying the strength of various woods, trying to come up with a simple procedure. Turns out, it's not as simple as I thought. I began with the procedures described by the Forest Products Laboratory but if you use their sample sizes you will need some rather large weights, so that by the time I was able to make my samples fail, the patio looked like an annex of the FPL. Which caused me to try using smaller samples, such as 1 square inch rather than four. And most recently, 1/4 of a square inch.

Samples using a quarter of a square inch reduce the test to table-top dimensions but the tests also produce a lot of 'scatter' in their results. Which lead to my trying to use samples that were the actual size of the wood being used. That turned out to be a pretty good idea because in every test I've done, the part was STRONGER than it needed to be.

I've designed the 'Chugger' to have a maximum gross weight of 850 pounds (1870kg) and to withstand four g's. That is, the wing, tail, and engine mount are supposed to survive a momentary overload of 7580Kg or 3400 pounds. So far I've been able to verify this for everything except the landing gear, which I'm still working on.

-R.S.Hoover

On the Wearing Out of Things

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Strop my old cut-throat razor as good as I can, that ten-cent throw-away it's laying on will give me a better shave. Oh, maybe not for the first stroke or two. Well-steamed whiskers under a layer of hot lather, there's a velvet touch to that first stroke of the blade. But after that the edge on the throw-away will pull steadily ahead until you feel slightly foolish, bobbing and weaving against your image in the outside mirror while the other campers try not to stare.

Little boy whispers too loudly to his dad: "What's that old man doing?" It's called shaving, son. Yes, even with a beard you need to touch-up the trim-work now & then. So rarely that an old fashioned razor makes good sense. That is, I used to think it did. But since I started adding to the planet's land-fill I'm forced to admit that a throw-away gives me a better shave.

The reason why that is true has a lot in common with why a lot of home-builders are throwing away as much as twenty-five percent of their engine's power. 25%

Impossible! (I heard someone say. Probably the grandson of the fellow who said nothing would ever beat his cut-throat razor.) The reason it is possible is because the fellow has never flown -- nor driven -- a professionally-built engine. And before you start telling me that I have to be wrong I'd like you to take another look at that old straight-razor of mine. Sharpen it to perfection and within half a stroke you can feel it starting to drag. That's all it takes to turn the edge. You can restore it by a few judicious strokes on your finest strop but you will have to repeat the process, half a stroke then strop... half a stroke then strop... as your shave progresses. By comparison the machine-sharpened blade in that inexpensive throw-away is good for about one and a half shaves before it even begins to dull.

There's really nothing new in all that. Cutting tools dull in use, especially so when cutting metal. For example, when cutting the bores for the crankshaft and camshaft, they will start with multi-point cutting bar that creates a hole on the high side of the allowed tolerance. After cutting a certain number of crankcases they will gauge the bores, then cut a few more, gauge it again and keep repeating the process of cutting and gauging until the inspector tells the machinist it's time to replace his cutting tools.

In other words, there isn't a single perfect size but a range of sizes that grow steadily smaller as the machinist produces crankcases. This difference in size represents the tolerance for that particular machining operation. (You will find all of the tolerances listed in the factory workshop manual.)

Machining the bores for the two shafts generates a third dimension and its related tolerance. That's the distance between the center-line of the bores. Since the two shafts are coupled together by a pair of gears you will also find a range of acceptable gear sizes, each having its own tolerance.

Volkswagen used nine different sizes of gears. To properly assemble a VW engine your first step is to determine the fit of the valve gear. Which begs the question: What size valve gear does your engine use?

When you assemble an engine using the wrong size of valve gear two things are immediately evident. One is that the steel cam driver gear will commence to chew up the aluminum driven gear, generating lots of swarf to block your filter and contaminate your bearings. The other thing is that the engine will not produce as much power as if would if fitted with the proper gearing. But worst of all is the culmination of those two errors. Not only is the bad to begin with, it will become steadily worse in use.

Engines are incapable of healing themselves. Start with a bad lower end and things can only get worse. But engines are capable of humor. Ask someone what size cam gear their engine uses and the odds are they won't be able to tell you, even though they have just spent half an hour expounding upon their experience as a builder of VW engines. And while they can't tell you what size gear they used -- many will even argue that only one size is available -- they are equally sure that, whatever size was needed is exactly the size they've used :-)

The reason I've mentioned all this has to do with the following scenario: Someone has just spent a sinful amount of money to assemble a 2180cc VW engine. But having done so, when pitted against a supposedly identical airframe and power-plant they have discovered their engine is not quite as powerful as they expected. Indeed, a few have had the unfortunate experience of having a similar airplane fitted with a smaller engine out-climb them. And go faster. And burn less fuel.

Obviously, something is seriously wrong. He's paid all that lovely money and done everything the various experts have told him to do but he's in much the same situation as the fellow with an old straight-razor who discovers he can get a better shave from an imported throw-away that costs only a dime.

Another aspect of this scenario is purely personal and may be an error on my part. As best I can recall, I used to be asked what's wrong with my engine three or four times a year. But since being diagnosed with cancer (June, 2008) it seems that question is popping up more frequently than before. (I can imagine what you're thinking. Believe me, pard, I've been thinking the same thing :-) But win, lose or draw, I think all we can do is play the cards we're dealt. So, whether the question has been coming up more frequently... or even if I'm just thinking it has, it seems worth addressing, which is the purpose of this article.

So how do you help someone diagnose an engine problem via email? It's a bit harder than it may appear because while you must address the engine as a system -- as something that must work together as an harmonious whole -- when the components are produced by a chaotic collection of manufacturers, you must begin at the component level and work your way up. Each component is blueprinted, then components are assembled into sub-assemblies and -- finally -- you can assemble the sub-assemblies into that harmonious whole.

The reason this difficult is not the blueprinting nor the assembling into sub-assemblies. Those tasks, while time consuming, are quite straight-forward. The difficulty arises from what you must do when a part or sub-assembly FAILS to meet its required specifications.

In a factory, any part or sub-assembly that fails to meet spec is simply laid aside to be re-worked, substituting parts until you achieve the desired goal. But the homebuilder is usually working with only ONE ENGINE'S-WORTH OF PARTS. If they are an experienced automotive machinist they may elect to re-manufacture the supposedly 'new' part. Or they can try to get the supply to ship them a replacement. Or whatever. The truth is, the MOST DIFFICULT part of assembling an engine today is simply finding one engine's-worth of parts.

Many of the fellows needing help have removed and dismantled their engine, looking for the Smoking Gun that is preventing them from flying as fast or climbing as quickly as those Other Guys.

But when the engine is still on the airplane, and has flown enough hours to establish a history -- say, a hundred hours or so -- you can leave it alone and assume it has been properly assembled. And yes, it is a risky assumption; a double-edged blade that can cut you both ways. Such as the fellow who casually asks: "You keep mentioning Compression Ratio... What is that, exactly?" Or the fellow who thinks a 300 fpm Rate of Climb is okay... in an airplane that normally climbs at about a thousand feet per minute.

What you're running into here is the fact that in many cases the person seeking advice is unable to evaluate good performance from bad performance because they have only one airplane's-worth of experience. Or the fellow who's engine has more than an eighth of an inch of end-play. But it starts at the first flip of the prop and never gives any problems... So why should he change things?

(Yeah, I'm smiling too. But I'm also serious. I get a lot of questions you really would not believe.)

So the root of the Decision Tree is bifurcated into Component Level Questions and Hundred Hour Questions. For the purpose of this article I'm going to start with the Hundred Hour Questions and do so by starting with the Lower End -- crankshaft, camshaft, con-rods, pistons & jugs, cam gearing, valve timing and so forth: the foundation of the engine.

Ninty-nine times out of a hundred the search ends at the cam gear. There is simply no reason to continue when we lack the basis for setting the valve-train geometry. And when you can't set your valve train geometry the probability of giving away as much as 25% of your power is very real indeed. As is the likelihood that you would not be aware of it. In fact, there is no accepted standard of success when it comes to the conversion of Volkswagen engine for flight. The fellow has assembled an engine and the thing actually ran! Even more amazing, it produced enough power to fly the plane! Clearly, we are dealing with the epitome of success. To have someone come along and imply that things could be even better...

The only down-side to the supposition that any engine which runs and produces enough power to fly the plane is a success is the specter of catastrophic failure. One of the most compelling reasons for the use of an Otto Cycle engine is that it provides a number of easily recognized precursors well in advance of any mechanical failure. But that is only valid when the engine was properly assembled to begin with.

-R.S.Hoover

Cure!

Gotcha!

Well... sorta gotcha. It's actually 'cure'. Lower case and quotes... because it is a magazine.

Yup, they seem to have one for everything nowadays. It's a quarterly and as you may have guessed, it's a freebie... if you've got the Big C... or have had the Big C... or know someone who has. Or had. Or whatever. If for some incredible reason you don't qualify for a free subscription -- such as living on the planet Logoff -- then it's twenty bucks a year. So... on the up-side it's another source of information for me to add to an already mind-boggling work-load but the down-side is that it appears to be just another outlet for pharmaceutical PR. Still, I have got to read it.

Some of you won't understand the absolute imperative there so lemme run it by you.

Mention car, firearm, airplane or half a dozen other things and all you'll get out of me is a nod; yep; got all that; let's move on. In those areas I am adept. Not a tinkerer nor a casual user but someone who can build you a car. Or an airplane. Or a mechanical clock that keeps reasonably good time. No sense in our discussing those things nor in my reading about them because the odds of encountering something truly new is vanishingly small. Skim it to the point of identifying a linkage to my existing knowledge in that particular field and if you listen very hard you'll hear the gates of my biological copy of Babbage's falling into place. Next topic please. This ability is probably a sex-linked trait as I've only met a handful of women who have it. Oddly enough, while a lot of men -- probably a majority -- have it to some degree, most are not aware of it. Acquisition of this uniquelly male trait has been through peer-group osmosis rather than a conscious effort. Then too, you would probably have to interrogate them rather closely to have them regurgitate the specifics for making steel. But it's all there, mixed up with the inherent male inability to remember dates deemed important to the feminine mind, or to admit to being lost when we haven't got a clue, and the inability not only to lie gracefully but even wanting the native wit to understand the absolute necessity of lying when harmonious interpersonal relationships with opposite sex is the goal. (What does the color of furniture have to do with anything?)

But when it comes to me and cancer, I'm not even up to novice-grade in the knowledge department. Which means if it has ANYTHING to do with cancer, I HAVE to read it. I've no choice in the matter. I was diagnosed with multiple myeloma in June of 2008. At a guess I've probably acquired less than 1% of the available information and even that has to be qualified as meaning information in digital form.

It doesn't matter that the new magazine is a gimme, it's value somewhere between a bathroom wall and a bumper sticker, it is a source of information about cancer so I must at least scan it. But even that takes time.

Maybe I'll send them an article about... some damn thing.

-Bob Hoover