Thursday, July 10, 2008

Doing Your Vitals

'Way back when, a lot of teachers were also nurses. Mrs. Doyle was one such lady who returned to teaching Third Grade and serving as the School Nurse during WWII, when we simply didn't have enough pople to go around. But there was a war going on and rather than just talk nursing, Mrs. Doyle taught it, starting with basic health. She gained our respect by producing an antique sphygmomanometer from an equally antique Black Leather Bag and commenced to give the whole class a tune-up. Indeed, she was not satisfied until the whole damn class had learned how to determine Blood Pressure. But that's just the tip of the iceberg. When you say vitals the implication is that you are recording:

Blood Pressure
Pulse Rate
Respiration Rate
Body Temperature
Height
Weight... and so forth.

That last ...and so forth... looks unscientific as hell but it makes sense to a kid. Along one wall each student had a list showing our body weight, height, color of hair & eyes and several other data elements, some not specific to human vital signs but all of profound interest to a gaggle of eight year olds.

Even more interesting is the fact we collected the data ourselves. And if you think that's a Big Deal, it's not. In fact everyone should be able to not only define their vitals but should have no trouble collecting such data and recording it in a tabular fashion.

Because that's what you do when you get sick.

Ecept nowadays, most folks don't. In the modern world you simply plug yourself into your computer and let it collect your vitals automatically. That guarantees less chance of making an error when you collect the data but it also ensures more uniform reporting. It also guarantees the data will be communicated to whoever needs it.

Which is why you could have knocked me over with a feather when a local 'health care worker' shows up to 'record' my vital signs.

Mebbe when digging the Panama Canal but definitely not in the 21st Century. By the time the 'health care worker' has driven to your home, imposed themselves on you, recorded your vitals -- correctly, I hope -- you are looking at a significant cost in time and gasoline.

-R.S.Hoover

Saturday, July 5, 2008

Cancer

Yes, I've got it.

No, you can't have it. You have to grow your own. You don't catch cancer. It's not a head-cold or a case of clap. I've been working on mine for more than five years now. It's called Multiple Myeloma and it has lead me a merry chase, partly because the first symptoms appeared as a kind of transition variety and all those fancy, infallible scanners and CATZ and PETZ and sooper-dooper hi-teck never-wrong space-age machines were DEAD WRONG. Indeed, I was I was healthy as hell according to them... and they were right. Unfortunately I was in the process of developing multiple myeloma so that while I was healthy then, within a matter of weeks I was now not... even though I had just completed a series of expensive, time-consuming tests that said I was.

One of the trickier bits about Multiple Myeloma is that it likes to attack people who are about forty years of age or older. Need I mention that includes a lot of pilots?

If you just found out you've got it, you're one of about 15,000 others in the 40 - to - 65 age-group who joined that years club. After getting the good news an awful lot of these guys make it as far as the parking lot before blowing out their brains. I mean, after all... they've just lost their ticket, everyone is moving to larger airframes rather than smaller ones and career-wise our boy is on the lower cusp, for whom a lab report ...perhaps accompanied by a friendly tranquilzer... has just guaranteed the world as he knew it has ended.

Okay, stats vary and I don't want it to appear worse than it is but I've had the misforturne to see this scenario played-out twice, up-close and personal. My own situation aside, I'd rather it didn't happen again so howzabout following me through on this one?

The Biggie is that some forms of multiple myeloma are TREATABLE. Okay, so there's no ATR in your wallet when you get done but at least you are still there.

Treatable means you can't have my plane... go build your own. But we -- and I'm talking the aviation community, your family and what all -- we've still got you. That puts us miles ahead of the game. So don't get all teary-eyed on me. You've still got the Big C! (and so do I). It's awful. It F**king Hurts! It's NOT FAIR!!

So suck it up and let's get on with our lives.

-----------------------------------------------------------------------------

Like I said, some forms of multiple myeloma are treatable and I'm a living example of someone who ha
s just started through the process. I've done the wet hanky bit, hid in the corner for a major bout of boo-hoo's, then then did the Oh So Sorry me but my God that sonofabitch hurts!

Weak as a cat, too. (But I'm working on that.)

Kinda confused. Chemotheropy guarantees you're going to kinda dingy now & then but but trust me, I passes.

What you need, right now and for a good while to come is your friends. And you can go ahead and count me in, if I'm not already on the list. Because with multiple myeloma the emphasis is NOT about grabbing your friends by the handles and dumping them in a hole in the ground, it is about getting BETTER; about HEALING. And I'm not standing here blowing smoke. Hell, I'm still making rigs for Chugger's wing ! (and no tranks in the pill compartment this morning).

(And I've still got three damn engines to finish :-)

-------------------------------------------------------------------------

So what about you guys who don't have 'chugger' waiting in the wings? Then you're going to have to get one...
or something damn near identical.

-------------------------------------------------------------------------

Plus you've got to learn how to SLEEP.

Deep, rich rewarding SLEEP. Because based on my limited (but growning experience as a cancer victim) sleep appears to be the catylyst for cure -- or at least for healing. The only problem is that everything is all so new (!) and there is so much to learn. To make matters worse you usually look like the dog's dinner and feel even worse.

Tough Darts.


About half the time, multiple myeloma is trying to kill you on purpose and the rest of the time it does a fair amount of damage through pure chance, all the while you are rattling like a goard from all the pills you've stuffed yourself with. Most of the pills are an effort to control the pain, others are there to help control the side-effects of the chemicals that are suposed to help you GET WELL and a very critical aspect of that effort is the need to maintain accurate records. The records are needed to maintain the proper balance between pain management and chemotherapy. Need I mention that if you aren't a good clerk at the outset you'll soon become one!

So what works? What's the Secret Weapon?

I haven't the foggiest notion.

But I do know that Jesus never owned a Cadilliac and Mohammad had never actually seen a real oil well although it's fair to assume both enjoyed a wealth of real friends, the kind you can't buy.

So let's start with that


----------------------------------------------------------------

29 June -- Home from the hospital, I pretty much lived in this chair for three days & nights because it simply hurt too much to lay down. We finally got that worked out .

You can't deal with the tumor until you've figured out some way to deal with the pain.
















Friday, May 16, 2008

Chemicals


The chemicals shown on the left are all you needed to assemble an early Volkswagen engine (ie, 1100 & 1200). The valves were so small that relatively weak springs were enough to close them. Since the springs put only a modest load on the cam & followers, a special break-in lubricant was not needed.

Except for its color -- German 'permatex' was black -- the standard American stuff worked fine for sealing. If the crankcase parting-line was badly corroded we'd spin a few strands out of a hank of silk embroidery thread and embed the strands in the thin layer of Permatex we had painted onto the parting-line of the left-hand half of the crankcase.

Permatex was also applied under every washer on any stud or stay that had oil on the the other side. Or on this side, which is the case for the four lower head-stay nuts in each of the heads. Oddly enough, although this has been a standard VW assembly procedure since about 1937 a surprising number of today's experts ignore this vital step. And wonder why their engines leak :-)

Ditto for the Loctite, which the German mechanics I learned from adopted as soon as it became available. Prior to then they used gasket shellac, but only after carefully cleaning the threads of all debris & oil, another of those 'unimportant' steps usually ignored by the modern-day expert.

Shortly after the introduction of the 1300 a wide range of thread-lockers and thread restorers became available, and not a minute to soon. The explosive increase in VW sales in the early '60's caused many engines to be damaged by unqualified mechanics. Having no experience with air-cooled engines it was common for American mechanics to assume the VW's torque values were incorrect and apply the Model T Torque Rule, which was as tight as they could get it... plus one turn. I'm sorry to say that's still the case with many VW 'mechanics.'



When the 77mm barrels of the stone-reliable 1300 engine were bored out to create the 1500 engine we began to see an increased frequency of case-shuffling and accelerated cam wear. Volkswagen was aware of the problem and began work on an aluminum-cased 1700 engine but it would not appear on the scene until 1968. In the meantime VW issued a number of SB's and SN's (ie, Service Notes and Service Bulletins) telling us to dope the cam & lifters of newly assembled engines with molybdenum disulfide grease, and to '...locally treat' various gaskets to prevent them from leaking.


To be honest, none of it did much good when they over-bored the 83mm jugs to create the leaky, trouble-prone 1600 engine. Then came the untimely death of Heinz Nordhoff and the engineers -- real car people -- lost control of the company, to be replaced by accountants more interested in short-term gains than long-term quality.


Nowadays it takes a bit more than a can of Permatex to assemble a reliable, durable leak free engine from VW components, especially so if you're building a big-bore stroker suitable for powering a light airplane.

Not according to the experts, of course... those wunnerful folks will look you right in the eye and swear all Volkswagens leak. Or at least, all the ones they've ever built :-)

At the time Volkswagen of Germany stopped making air-cooled engines there were a lot of Service Notes and Bulletins that hadn't been incorporated into the Factory Workshop Manual and in so far as I know, they never were.


Do you like barbecue? Most folks do. Of course, there's half a dozen different styles of 'barbecue' and a different sauce or rub for each, with variations based on the type of meat. The picture above shows the ingredients for one style of barbequed pork. To have it come out right you not only need to know which ingredients to use but how much of each, and -- believe it or not -- the sequence in which they are mixed and the method the sauce is applied.

All of which are considered unimportant details by someone who doesn't know how to cook.

A VW engine converted for flight is an airplane engine. It's not a dune buggy engine nor a hot-rod engine nor something to take to the drag-strip. The sad thing is, a lot of people don't know that.

-R.S.Hoover

Sunday, May 11, 2008

Rudyard Kipling

My grandfather thought Rudyard Kipling was the worst sort of bigot even while admiring him as a man of letters. He had quite a few of Kipling's books that we children were encouraged to read. I imagine my dad had to run the same gauntlet. In fact, one of dad's favorite expressions was, "An engine can't lie to you," which I later learned was probably taken from Kipling's "The Secret of the Machines."

...We are not built to comprehend a lie,
We can neither love nor pity nor forgive, ...

I'm guilty of using the same expression, especially when someone insists their VW engine converted for flight produces some prodigious amount of power. Pointing out that engines can't lie... but people selling them can... usually gets me an angry message or two from someone insisting their converted VW really does produce a hundred horsepower or more. And the surest proof of that is the fact they own it... because if it didn't produce that amount of power it would mean they had been cheated, which is impossible because they happen to be a physician. Or an airline pilot. Or some wealthy champion of industry. Or whatever.

But such messages also tell me there's a lot of folks out there who have never read Kipling :-)

The Secret of the Machines

(MODERN MACHINERY)

Rudyard Kipling


WE WERE taken from the ore-bed and the mine,
We were melted in the furnace and the pit—
We were cast and wrought and hammered to design,
We were cut and filed and tooled and gauged to fit.
Some water, coal, and oil is all we ask,
And a thousandth of an inch to give us play:
And now if you will set us to our task,
We will serve you four and twenty hours a day!

We can pull and haul and push and lift and drive,
We can print and plough and weave and heat and light,
We can run and jump and swim and fly and dive,
We can see and hear and count and read and write!

Would you call a friend from half across the world?
If you’ll let us have his name and town and state,
You shall see and hear your crackling question hurled
Across the arch of heaven while you wait.
Has he answered? Does he need you at his side?
You can start this very evening if you choose,
And take the Western Ocean in the stride
Of seventy thousand horses and some screws!

The boat-express is waiting your command!
You will find the Mauretania at the quay,
Till her captain turns the lever ‘neath his hand,
And the monstrous nine-decked city goes to sea.

Do you wish to make the mountains bare their head
And lay their new-cut forests at your feet?
Do you want to turn a river in its bed,
Or plant a barren wilderness with wheat?
Shall we pipe aloft and bring you water down
From the never-failing cisterns of the snows,
To work the mills and tramways in your town,
And irrigate your orchards as it flows?

It is easy! Give us dynamite and drills!
Watch the iron-shouldered rocks lie down and quake
As the thirsty desert-level floods and fills,
And the valley we have dammed becomes a lake.

But remember, please, the Law by which we live,
We are not built to comprehend a lie,
We can neither love nor pity nor forgive,
If you make a slip in handling us you die!
We are greater than the Peoples or the Kings—
Be humble, as you crawl beneath our rods!—
Our touch can alter all created things,
We are everything on earth—except The Gods!

Though our smoke may hide the Heavens from your eyes,
It will vanish and the stars will shine again,
Because, for all our power and weight and size,
We are nothing more than children of your brain!


Friday, April 11, 2008

The Apprentice's Toolbox




They were told to be there at 0730 and, with rare exception, they always were, at least on that first all-important day. There was never less than thirty-two of them, never more than thirty-six. The youngest had just turned fourteen, the oldest was a day shy of eighteen. There were no exceptions to this rule.

It was always a mixed bag that stood nervously outside that hangar door, with an occasional turban or fedora among the cloth caps. Especially nervous were the Africans, knowing they were in a country where lynching members of their race was still considered an acceptable form of behavior. A sprinkling of Orientals rounded out the racial mix but often confusedly so since some were lanky six- footers. The confusion was compounded by native- born Chilean named O'Hara who spoke better German than Spanish and a Chinese boy whose mother tongue was Portugese.

And English, of course. English was another rule for which there was no exception. English was the language of aviation.

At exactly 0730 the door opened and a man bearing a clipboard stepped out. Without greeting or preamble he called the first name, got a startled reply from the surprised boy who was told "One-one," and saw his name ticked off the alphabetized list. The man went on to the next name and the one after that before he noticed the first boy was still there, a picture of worried indecision.

"Table one," the man said slowly. "Table one, place one. Inside," the man gestured abruptly with his pencil and went on to the fourth name who became 'one-four'. Number five became 'two-one' and the mystery was revealed as soon as the boys entered the building.

The tables were right there, impossible to miss since they occupied half the extensive space. Varnished maple tops a solid two inches thick, four feet wide and eight feet long, supported on steel legs painted grey. The ten tables were clearly marked with their numbers and the four places at each table was also marked. But the boys hardly noticed.

The remaining half of the space was occupied by an airplane. The boys immediately recognized it's make and model although few had never seen one in the flesh. Having their eyes fastened to the plane made it difficult for them to find their places at the tables but all eventually did so, even though their heads remained cocked toward the airplane. The airplane was why they were there. It was a dream come true, a thing too exciting to ignore.

But as soon as they were all at their places the man, who said simply "I'll be your instructor," explained sorrowfully that they would all have to go back outside. Someone had created a bit of a mess - - two cigarette butts -- and it would have to be cleaned up.

First one then the other of the guilty boys confessed their crime and moved toward the door but the man would not allow it. It had to be all or none. That's how things were done here. And so long as he was in charge, it would be all.

Brooms and dust-pans were found and the area in front of the building given a brisk but effective sweep-down. But by the time the brooms were put away several boys had forgotten their numbers. And again, it was all or nothing. Rather than look up their numbers individually the man called the entire roll.

Each table held four drawers and the space under each table was marked off into four sections. Inside each drawer was an identical kit of tools and an inventory sheet. Each boy was required to inventory his tools as the instructor called them out, marking them off on their inventory sheet which the boy then signed. Lining up by their numbers, the boys were conducted to a room on the far side of the building where they turned in their inventory sheet and received back three shop coats of a size appropriate to their build. Or nearly so.

The shop coats were glorious things of white cotton twill, embroidered across the back with the winged symbol of their employer. They were told to reserve one of the shop-coats for special occasions and to keep the other two properly washed and mended, for it was now their daily uniform.

Properly frocked and tabled, the boys were then addressed by an older man in a three-piece suit and gold-rimmed glasses, obviously someone important from the Front Office. The man spoke in a friendly, familiar fashion, smiling often and making it clear he thought them a welcome addition to the company, which is why the company was willing to go through the expense of training them for three years, providing them with their shop coats and working space, their basic kit of tools and of course the all-important toolbox to keep them in...

At which point the Instructor leaned near the Important Man and told him they were out of toolboxes at the moment but just as soon as some came in...

The Important Man didn't care for this news. Not one bit of it. He frowned and when he did so all the warmth went out of that wonderful airplane- filled space. He reminded the Instructor that the apprenticeship program was costing the company thousands of dollars and that there was a right way and a wrong of doing things and any attempt to properly train an apprentice who did not have his own toolbox was obviously wrong. They would have to send the boys home and reschedule the start of their training... at least, for any who were still qualified, for some later date. Insert here a dramatic pause, during which apprentices had been known to faint, burst into tears or lose control of their bladder.

"I suppose I could have them make their own toolboxes," the Instructor mused in a tentative way.

The Important Man gave the Instructor a scornful look. "That wouldn't do. They'll have those toolboxes for the rest of their lives. Everywhere they go people would see those toolboxes with our logo on them. We couldn't allow any shoddy goods... "

"Oh, they wouldn't be shoddy," the Instructor assured him. "Built to spec, every one of them."

Here the Important Man turned toward the boys. He didn't look pleased. "Are they up to that? Some of them don't have any training at all... "

"I'm sure they can do it if we give them the chance," the Instructor coaxed. Thirty-six rigid faced boys silently screamed 'Yes! Give us a chance!'

And so it was. The boys were trooped to another building where four sheets of sixty-thou 17ST was sheared into strips sixteen by forty-eight inches. In another shop each boy was given a piece of one- by-one by eighth-inch aluminum angle along with a paper cup half filled with rivets. In the Steel Shop each boy received a section of piano hinge, two luggage latches, a small hasp and a piece of 3/8" cold-rolled steel bar ten inches long. Juggling this crazy assortment of stuff, cutting themselves on the sheet metal, dribbling rivets, they scurried back to their classroom. It wasn't yet nine a.m. of the first day of their apprenticeship and things seemed to be going to hell in a hand basket. Or in a toolbox.

---------------------------

It was all a bit of a show of course.

Over the next two weeks each of the apprentices, save those who slipped quietly away and never returned, used the materials to build his toolbox. The sheet of aluminum -- when properly cut -- provided enough material to fabricate a toolbox approximately sixteen inches long, eight inches wide and ten inches deep. The corners of the box were reenforced with angle while the steel rod was bent to form the handle. The box was assembled with eighth-inch rivets having a one-inch pitch.

For many of the boys it was their first exposure to metal-work. For others, it was their first use of feet and inches and all those confusing fractions, so unlike the innate simplicity of their native metric system. And for most, it was their first experience with dust pans and brooms and working alongside a total stranger from exotic lands such as Nigeria or Oklahoma.

If the truth be told, a few of the toolboxes were less than spectacular when it came to workmanship. But each was built to spec. And each passed a rigorous inspection, not only from the Instructor but from the student's peers for here again, it was All or Nothing.

The resulting box was acid-etched with name of the apprentice and with the logo of the particular school. The details of the toolbox -- and of this story -- vary from school to school, with a Northrop toolbox being distinctive from a Spartan, as a Loughead differed from a Fleet. But the principle remained the same for all: With the manual arts, you learn through experience. Building your own toolbox was simply the first step on that path. But there was a far more subtle lesson being taught, one having to do with the nature of airplanes and teamwork.

Many a mechanic... and not a few executives... still have their 'apprentice box', often prominently displayed on their Trophy Wall among their photos, diplomas and other tokens of accomplishment.

-----------------------------------------

How about you?

Ever used a cleco? (or know how they got their name?) Ever made a buck-head? Have you been properly introduced to Mr. Smiley?

Building the basic box is akin to building the basic airplane in that you first fabricate the parts then assemble them into subassemblies and the subassemblies into the whole. Along the way you must do some accurate cutting and filing and drilling as well as figuring out half a dozen problems built-in to such a project, such as 'How do I get all twenty pieces of sheet metal out of this 16x48 panel?'

Frankly, it's a lot of work. And nowadays work is considered a bit old-fashioned, especially if it involves something you've never done before.

But the concept behind the Basic Box applies equally well to composites, welded steel or even wooden construction practices -- the Basic Box is meant to provide the means to an end rather than an end unto itself.

Want to build the Basic Box from fiberglas? No problem. There are at least four acceptable methods of arriving at the desired finished product. Howabout wood? The same applies to wooden construction. Or to steel. And in each case the object is not to provide you with a toolbox, it is to teach you welding or wood-working or many possible variations when working with composites.

So you do the work and in doing so, learn the required techniques. But it isn't some Quick & Easy, smear a little epoxy on the table sorta thing. Nor do you weld half a joint and skip off to the next booth to get a three minute 'education' in scarfing plywood. Under the Old Rules you not only acquired an in-depth knowledge of the required techniques and procedures, you made a useful thing, something that would last your lifetime, something better than anything you could buy... and something that could only be made by human hands.

Want to buy a 'prentice box'? I'll be happy to sell you mine. For ten thousand dollars :-)

-R.S.Hoover

Thursday, April 3, 2008

AV - Vapor Lock

Re: Vapour Lock (Question for Mr. Hoover)

--- In volksplane@yahoogroups.com, Stefan Vorkoetter wrote: > Can you tell me (and the group I guess) what vapour lock is?

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Gasoline, or whatever passes for gasoline nowadays, has a low boiling, typically between 80* and 90* on the Fahrenheit scale, the range depending on the formulation of the fuel, in that 'gasoline' containing a higher percentage of alcohol boils at a LOWER temperature. And to make matters worse, the boiling point decreases as the air pressure is reduced.

Heat your gasoline to its boiling point, it starts to do just that. Not like your tea kettle, but the liquid gasoline is still rapidly turning into gasoline vapor.

Did you get that bit about pressure? Reduce the pressure on your hot gasoline and it will start to boil at temperatures well below 80 to 90F (I forget the Celcius). Higher you fly, the lower the boiling point.

The pressure factor is really important if you have a fuel pump anywhere in your system and is of CRITICAL important is you're using the typical two-chamber automotive type pump, such as a stock VW mechanical fuel pump. That's because when the pump's diaphram is pulled down it effectively REDUCES THE PRESSURE on the fuel that appears in the inlet-pipe of the pump. And if the liquid fuel is close enough to the boiling point, the drop in pressure fills the lower chamer with gasoline VAPOR instead of liquid fuel. (This is the classic definition of Vapor Lock, by the way. Which never happened on the early Fords because they used a gravity-fed system.)

Wanna know the main difference between gases and liquids? (They're both 'fluids,' by the way.) You can COMPRESS a gas whereas liquids are virtually incompressible. And that's exactly what your fuel pump does -- it compresses the bubble of vapor in the lower chamber. The bad news is that compressing the bubble of vapor does NOT allow any gasoline to be pumped.

The really bad news here is that an automotive fuel pump (and most others) are not positive displacement devices. The outlet pressure of the typical fuel pump is generally less than 1 psi. If the lower chamber were filled with LIQUID, 1 psi would be more than enough to push the check-valve off its seat and force liquid gasoline into the upper chamber, where it would bet fed to the carb according to the position of the carb's float-valve. But when the lower chamber is filled with vapor, the pressure of the return spring under the diaphram simply compresses the bubble. Some of the vapor may get into the upper chamber but the bottom line is that within three or four cycles the fuel pump stops delivering fuel to the carb, the engine burns off the fuel in the bowl (if its a real carb) then dies.

That's the typical 'vapor lock' scenario. But there are others.

If the hot gas is in a pipe at atmospheric pressure, you're going to get SOME amount of vapor formation. In a properly designed fuel delivery system, your fuel pipe should ALWAYS have some degree of slope toward the carb, even when the airplane is climbing at its steepest angle. The reason for that is to allow any vapor to travel UP the pipe and be vented from the tank and for any debris that got past your finger-strainer to travel DOWN the pipe and end up in the gascolator. (Your fuel line is always sized to PERMIT the down-hill passage of any debris large enough to get through the strainer in the tank.) Sounds like plain old fashioned Common Sense but you'd be surprised what a rare commidity that has become :-)

One of the other vapor-lock scenarios is when the body of the carburetor becomes so hot that the flow of gasoline through the carb is not enough to cool it off. The gasoline boils and since the bowl is vented to the atmosphere, escapes. But in some cases, especially with automotive carburetors, the bowl is vented into the throat of the carb resulting in a mixture so rich that it can kill the engine. The Tillotson and, I think, most of the Zeniths, are vented directly from the bowl to the atmosphere so this type of 'vapor lock' but the Solex (all models) and most other automotive carbs dump the boiled-off vapor into the manifold.

As you can see, the root-cause of vapor lock is pretty simple, which makes its prevention a no-brainer. Unfortuantely, in the case of the VP, in an effort to keep the costs down the fuel system violates a lot of rules, such as mounting a Solex carb on top of the engine, forcing you to use a fuel pump. Which is fine for a car, where you can pull over and park, but it's not real smart on an airplane. (Yeah I know, Rotax does it too. Of course, when you pay twelve grand for a 1300cc engine you expect it to come with fully insulated fuel lines.)

-R.S.Hoover

PS -- a lot of modern vehicles use positive-displacement pumps with pressures as high as 135psi. (Under that kind of pressure you don't have to worry about vapor lock.) A pressure-regulator controls the feed to the injectors and any excess is returned to the fuel tank, which is usually fitted with a vapor recovery device and electronically controlled venting system, hilariously complex, ridiculously expensive and not repairable at all; replacement only. Which is one reason my daily driver is forty years old :-) (Runs fine, thanks. And its emissions are barely a tenth of the legal minimum.)

(the above was posted to the Volksplane Group in 2005)

Monday, March 24, 2008

Other Ribs


A two-place Primay Glider may appear to be a contradiction of terms but having such a beast on the flight-line can be the difference between a Group devoted to pancake breakfasts and one having a successful flight-training program for youngsters.

Since cost is always a factor in real grass-roots aviation, the two-place was built almost entirely from materials that were locally available. The 68" ribs were routed from doorskins and fitted with a grooved cap-strip. Airfoil is an early Eiffel, I think one of the '400' series.

R.S.Hoover
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