The Affleck affair
I was recently notified about a thread on the www.homebuiltaircraft.com site
that I might be interested in, concerning my Corvair crankshaft breaks. Below are the comments submitted to that
forum, and the email traffic that Mr. Affleck considers to be “extensive communication” with me back in
2007. Unfortunately for him, I don’t know how to use
the delete key when it comes to email…I save them all. I’ll
let you be the judge, after reading his diatribes, and my terse response at the
very bottom of the page. Almost
everything he said about our “extensive communication”
is either inaccurate, twisted, or an outright fabrication.
Most of the “education” he claims to have given me in the
emails below had already been published on my web page months prior, and/or
gained decades before. To give an
example, “beach marks” were covered in fracture mechanics and fatigue design while
I was earning a degree in mechanical engineering. The pattern on the crank was also referred to
as “beach marks” by an expert in aircraft crankshaft failure who recently
retired from Teledyne Continental Motors, when he analyzed the first broken
crank 18 months before Afflec contacted me. Apparently
he thinks the term “beach marks” is jargon only used by experts like him. That should give you some insight into his
comments below.
And I never “stated
4340 would be twice as strong at 5340 in a crankshaft”. My website still has the words he
“remembers”, but what I actually wrote was “I have no doubt that this crankshaft will fare far better
than the one depicted above, since the base material is already something like
50% stronger, and the radii will be much larger.” That’s a distortion of at least a factor of two, with a little
fabrication thrown in, but also incorrectly sites the original Corvair crank
material, which is actually 5140 rather than 5340. Only a few digits off, but you’re starting to
get the idea. If that’s not enough,
consider this line from one of his emails:
“I'm 64 years old, IQ 145,
Sat math 800, and I know
everything there is to know about internal combustion engines.” Note how he sends his phone number with
almost every email, and invites me to call so he can “answer all questions”. I never called him.
This guy is listed as
a retired electrical engineer in his Homebuiltaircraft.com
bio, with the following experience listed:
“Past Projects: engine overhaul. various major
maintenance. designing and building race car engines. extensive and thorough engineering study as applied to ICE. Design work on a 7 cylinder radial; including responsibility for
the cam disks.” So he’s done an
engine overhaul of some sort and flew some Cessnas. I wonder how many EGT and CHT probes those Cessnas had? Yet he argues with data obtained from 1130
hours of successful flight experience, as recorded by the EIS.
Notice that he sent me six emails
over the course of several days before I finally
responded almost three weeks later. Apparently
he wasn’t going to stop obsessing until I told him to go away! I’m not going to spend another minute trying
to explain any of the rants below, or highlight the BS…I think they speak for
themselves. CorvAircraft listers, KR builders, and people who know me will know that
what is spelled out below is a character assassination job done by an internet
troll who builds himself up by tearing others down. He was told to buzz off, and apparently
didn’t appreciate it. I’ve always known
that my efforts to thoroughly test, prove, and improve the KR and Corvair
engine was setting me up as a target, but I never dreamed that somebody would
twist the facts so much. The formatting
and every word of the bodies of the emails below appear exactly as written in
2007. See below, and you be the judge. A
preemptive aspirin or two might be a good idea…
John affleck
- January 10th, 2013, 04:29 PM
Re: Debate about Mark
Langford's 3rd crank failure
The people
getting interested in the new aftermarket crankshaft for the Corvair need to
read this; as it correctly states the facts. Mark Langford stated that 4340 would be twice as strong as
5340 in a crankshaft; this is ridiculous. He has a talent for getting the wrong
answer; I've communicated extensively with him by e-mail; I'm the only person
qualified to speak on this subject who has communicated with him; but he
decided not to listen. at that time he was in
love with his guru WW; who is a MECHANIC; and not an engineer. He's a good
mechanic and a disaster as a engineer; but that's what
you would expect. I'll explain exactly why his crankshafts broke on another
post here which you can look up; I'm not going to write the whole thing twice.
DO NOT BUY THE AFTERMARKET CRANKSHAFT; this is just more amateur screwing
around. Okay; this was intended to follow on the man's post to the effect that
only the modulus of elasticity is relevant; but I don't understand how forums
work; so this is in the wrong place.
John affleck
- January 10th, 2013, 05:23 PM
Re: Debate about Mark Langford's 3rd crank failure
Okay; trying to
reply to jsween. Do not buy an aftermarket
crankshaft. I have practically written a book about this damn crankshaft
already; the intention being to save people from significant injuries and
damage. I corresponded with Mark Langford via e-mail and with WW; to no avail.
First let's start with the picture; it's a duplicate of the picture of Mark's
first crankshaft failure; which inspired me to write to him in the first place,
(years ago). The picture is completely diagnostic. It leaves no room for doubt.
It leaves no room for speculation; I don't speculate anyway, I'm an engineer, I deal in facts not opinions. Let's dispose of the
"torsional issue" first. It is not torsional failure. Period. There's
nothing more to be said about it; the fact that Mark is referring to
"beach marks" on the break face and trying to sound like he knows
what he's talking about; is due to my corresponding with him in the first
place. Without me, he wouldn't know a beach mark from a beach ball. I
pointed out to him that engine design is a subset of mechanical engineering and
that people have been studying this subject for the entire twentieth century;
and I gave him the title of a two volume textbook from MIT on Engine Design; to
his credit, he bought the book. He also makes the statement that all the breaks
originated in the shaft radius with the cheek; this is simply false; and
obviously so. THE CRANKSHAFT RADII ARE NOT INVOLVED IN THIS ISSUE. "Is the
Corvair crankshaft strong enough for aircraft use"--In many ways this is a
typical civilian question; it's so broad and so ill-defined it doesn't have any
"answer". However, considering my audience, here; civilians; I will
simply say, YES IT IS. There is a way of estimating the "strongness" of a crankshaft, obviously a very
imprecise concept; and I explained that to Mark and he looked it up in the
reference book and seemed to get something out of this. According to the
standard engineering criteria for crankshafts; the corvair crankshaft is
"stronger" than the Lycoming or Continental crankshafts. This is not
an opinion; I don't do opinions; I hate opinions. As I say, according to the
standard measurable parameters of crankshaft design it is stronger; period. end of discussion. Okay; so now you want to know; why do the
corvair conversions break crankshafts; and for those of you who don't know;
there are more of them then Mark's. Ok, by the way, when WW, "our
guru" told everyone they would have to nitride their crankshaft; I
immediately wrote to both him and Mark Langford and told them NO; this is not
the answer. Now they will fail at 700 hours instead of 70 hours. Look up the
actual numbers for yourself. this is not an accident;
this is not "luck" on my part; this is call shot pool; I am not an
amateur. Mark refused to listen; due to being hypnotized by his Guru. so he broke his second crankshaft. I've been waiting for the
third one, with the stupid front bearing to break; but I see I missed the
actual event. This is understandable because the only reward I got for trying to save these amateurs from themselves was to be
told "you're not a Corvair Expert" !! This reveals a sort of divine
idiocy. If you specialize in engine design as a subject in mechanical
engineering and have a SAT score of 800 out of 800; then you are a Corvair
expert; because the damn thing is an engine. Okay, back to why they crankshafts
broke; the picture reveals beyond a reasonable doubt as they say in court; that
it is a bending failure. What does this mean? Imagine a bobby pin; well maybe you're
not old enough t know what bobby pin is; imagine a
tuning fork; it has two legs and they vibrate relative to each other. Now look
at a picture of a crankshaft; could be a corvair crankshaft, if you like; see
that the structure comprising the rod jounal, the two
cheeks, and the main journals, resembles a tuning fork; as we say, it is
topologically identical. So, what the picture of the break is telling us is
that some force that was applied cyclically, to the ends of the U shapped structure caused the WEB to break; exactly where we
would predict it would and in exactly the correct orientation. It is a tuning
fork fracture. it's so common, it even has a name. The
provision of the front bearing moved the critical bending, (NOT TORSIONAL
BENDING), back to the second U shaped structure; not too surprising. Not
really, predictable; I mean I didn't predict this; as I did BOTH OF THE SECOND
AND THIRD failures. Okay, now are we all clear that it has nothing to do with
con. rod loads. rpm. loads, hmm? Is it straight in all our heads now? Because that's what NOT TORSIONAL means. Connecting rod load
shaft failures don't look anything like this; nothing; nothing at all. Nothing
reveals the commenters complete and total innocence
of knowledge more perfectly than looking at this break and than wanting to talk
about con. rod load, and cylinder size, and whatever
was hanging on the back end of the engine. You have only to ask yourself what
is attached to the crankshaft that bends it back and forth like a little tuning
fork 3,300 times a minute? the
prop. The Prop. is attached
to this end of the crankshaft; this should be a big clue, folks! And then, if
we were actually educated in this subject instead of just babbling at random;
we would immediately think of a little item called "Prop. Indexing". Prop. Indexing is a known and understood
subject in piston engine engine aircraft. Right now,
Mark is flying a Continental 0-300 engine in his new airplane; if he takes the
trouble to buy a factory overhaul manual for this engine he will find out that
Continental requires that the installer of the engine INDEX the prop. What does
this mean? It means the two bladed prop. only goes on
the mounting flange in a certain position; it has to be CLOCKED. In the case of
the corvair engine; which doesn't have a aircraft
application; you have to figure this out for yourself; which I have done for
you. Looking at the front crankpin of the crankshaft, install the prop. so that the blade is at ninety degrees to the tuning fork. if the front cylinder is at top dead center, or bottom dead
center, doesn't matter, then the prop. MUST BE STRAIGHT UP
AND DOWN. And that's it. that's the cure. Now
there are no more broken crankshafts. No Nitriding, No new front bearings
designed by mechancs; no; just this. This explains
why some break and some don't; because the great GURU, ww,
being unaware of this, doesn't specify a prop index. therefore,
they are clocked at random; the builders are innocent; nobody told them any
different; and from there it is strictly a matter of luck; is the propellor at ninety degrees to the little U shaped crank? or 60 degrees, or 15 degrees. Just a
matter of luck. DO NOT BUY THE AFTERMARKET crankshaft; Mark's statement
that the steel they have chosen is "twice as strong as 5340" is complete
ignorance. the REAL PROBLEM, is that these will be
manufactured by turning out of round stock, (ignorantly called "billet"by the amateur engine designers who do this),
on a lathe. The original factory product was a HOT FORGING. the
new replacement crankshaft will be TWICE AS LIKELY TO BREAK. I tell you t his in all seriousness, people; this is a serious
subject. Spread the word around. repost this. These
people do not know what they are doing. Now you know the answer; apply it and
fly in confidence; ALL OTHER OPERATING PARAMETERS of the Corvair crankshaft are
superior in the as installed flight application to either Continental or
Lycoming cranks. Period. this
is not an opinion. I wlll not be responding to any
comments; don't waste your time. you have the
knowledge, now use it. I've done my public duty. I'm not even faintly
interested in your opinions, and if you are; you are very foolish.
john affleck – posted January 13th, 2013, 05:32 AM
Re: Debate about Mark
Langford's 3rd crank failure
One person
actually said thanks; which is a polite response to the time and effort I put
in trying to explain this; so I'll try once more. First, Remember, I've already
been through this with Langford and Wynn; pages and pages and pages of it. It
makes me upset because peoples lives are at stake, here, I am a pilot, I put a
couple of thousand hours on a pair of Cessna aircraft that I owned; but that's irrelevant
as it does not teach you anything. First you have to go look at the picture of
the crankshaft break which you have a reference to here; at the top of the
page. the picture tells you a great deal. the reason steel has fatigue fractures is because it gets
bent a little over and over again;(this is in plain english
instead of technicalese;normal language is quite
adequate to explain the situation). the pattern of
marks at the fracture line tells you in what sense, or direction the bending
was occurring. That is why we have to immediately stop wasting time talking
about torsional vibration, or torsional bending. because
it is not involved in this series of failures, (they are all identical). You're
going to have to look up the picture as your part of understanding this.
Education is useful mainly because it alllows us to
eliminate possibilities. Torsional problems in the case of a crankshaft mean
loads that twist the shaft; so now we can stop with all the stuff about what''s hanging on the other end of the shaft and etc. Because it's not involved in this series of failures. torsional problems are notorious in recip. engine-propellor combinations; but there is no torsional component
here. If you imagine yourself holding on to the two ends of the propellor blades and pushing and pulling with your hands
then you will be generating the kinds of forces that caused this problem.
Notice that this pair of forces, tries to open and close the U shaped structure
formed by the rod journal the webs and the main journal. If you mount the propellor at ninety degrees to this U shaped structure; you
change the natural frequency of the assembly by a huge amount; an amount so
large and so significant that you can no longer excite the U shaped tuning fork
with the propellor "P" forces which are as
is well known somewhat lumpy as the prop. goes by the
wider part of the cowling and then the narrower part and so forth. Please
notice that the random clocking of the prop. which is
what is actually done in this conversion corresponds to the random nature of
the breakages. (some break; some don't). furthermore; the fact that the first break reported by Mark
Langford occurred so early in the operating history, (at low hours), is very
significant; it tells us something important. It tells us that this is a
"gross"; or large excursion in bending beyond what would be safe.
This is why I was able to confidently tell him, and WW. that
nitriding would not fix the problem. Because it is know, amongst those of us
who are educated in this field, that nitriding does "so much, and no
more". A crank that breaks at 70hours is an engine application problem; it
can't be fixed by nitriding. You see why I don't want to discuss this if you
look at the responses; "it's a combination of torsional and bending
loads". People just go on pretending that they know things that they don;t know and refuse; apparently
to even look at the photograph; or read what I wrote carefully. Of course crank
journal radii are important in crankshaft design; but the point I'm making is
that that is not a factor in this series of failures. Mark is just sailing off
into guessing land again with all the stuff and pictures about crank radii. If
you bend the material sufficiently back and forth 200,000 cycles per operating
hour; it will fail. if it bends less than the certain
amount; then it will not break. And you want to question my statement that a
Corvair crankshaft is "better" or "stronger" than a
Lycoming or Continental engine. we're using
simplified, civilian language here; "stronger" is not a precise term;
but never the less; as I told you, there are standard parameters of crankshaft
design that allow one to say; this crankshaft has a larger safety margin than
that one; and these parameters do show that the Corvair crank is "stronger"
than the others. I mean, there's a limit to what I can do here; I can't write
you a book. If you think about it for a minute you'll realize that general
motors has a huge engineering dept. and a huge budget compared to either
Lycoming or Continental; and they're manufacturing process at that time was
second to none in the world. The crank is a hot forging; the reason you not
supposed to buy the aftermarket crank is because all cranks turned on a lathe
from round stock are defective compared to cranks produced by hot forging. this is not controversial; it's common knowledge. If you
want to buy "The Internal Combustion Engine in Theory and Practice",
by Professor Charles Taylor, MIT, press; you can find out a lot about
crankshafts; they also have some nice pictures in there of breaks. Another
commentator on here begrudges me the exact angle recommended by Continental;
versus what I recommended to you for the Corvair Engine. If you read what I
wrote; I said they recommend a procedure for a specific engine; and I'm going
to give you a procedure for this engine. the reason
you want the prop. at ninety degrees to the front
journal is to make the maximum increase in critical frequency; this is not
controversial; advanced people in this field understand this. the other manufacturers have other things to take into
account; which are not your problem; your problem is simply a cyclic reverse
stress bending failure; and it will be eliminated by the procedure I
recommended to you. Why is the extra front bearing stupid? well,
do you consider fixing what's not broken, intelligent? there's
more about the WW conversion that's wrong too; but this is the most serious
issue. Another thing you definetely don't want to do
is to use a high volume oil pump; the oil pump drive on these engines is not
particularly robust; I would expect in flight distributor drive gear failures
if you insist on a high volume oil pump. this; of
course is just as bad as a broken cranshaft; it's
also being promoted by our favorite mechanic turned engineer, WW. I designed a
camshaft for the aero app. for this engine but I lost it a few computers ago;
it's only worth about 12 or 15 horsepower over the one they use now, which was
designed for a high rpm auto. app. Well; I have to
stop typing now. Either that or write a book about you should actually convert
a corvair engine for flight use and publish it. Oh, and don't use Mark's
cooling system either. Use the WW cooling system. He's an excellent mechanc and technician and I wouldn't hesitate to use a lot
of the parts he fabricates; on the other hand there's a conflict of interest
there. It's too bad he refused to listen; because as you can see the solution
to this problem is absurdly simple and costs nothing. My 70 year old fingers
are getting tired. goodby and
good flying weather.
From: John Affleck
To: Mark Langford
Sent: Monday, January 22, 2007 10:29 PM
Subject: Corvair conversion
I studied your original material up to your crankshaft failure and just now reviewed your updates, Basically, Wym. Whinn or whatever sp.is a mechanic and has no engineering knowledge by acting as a consulting engineer and "designing" these conversions he's done a lot of mischief. The "steel safety shaft" as you refer to it, is a perfect example of something which must never be done; putting threads inside the crank nose is a big no-no. This shaft provides leverage to "help" break the crankshaft. I have about twenty different things to tell you about engines that you don't know and you need to know. I just can't type that much. Here's one quickie, the spark plug you show as ,"detonating, if I didn't know better", was detonating during some periods of it's existence; you don't know better. The visual evidence is primary and direct; transducer readings; even if they were examined for every minute of operation are secondary. Your automotive compression readings of 175-185 psi reveal that this engine is not set up to operate on 93oct. The "compression ratio" so much paid attention to by amateurs, and many professionals; is relatively meaningless in determining ocane rating of the engine. Compression pressure is the determining parameter. 175psi is borderline possible for professionally tuned water cooled engine; It's "helping" a lot in putting your engine on the ragged edge of survival. In order to change this go to the OT-2 or O-20 or whatever in stead of the "little cam" from your supplier; and install it straight-up; check the compression again. I'm 64 years old, IQ 145, Sat math 800, and I know everything there is to know about internal combustion engines. I can't write you a whole book, I don't even know if you want to listen. The rest of the problem is caused by fuel distribution I would imagine, contrary to Williams assertion, it's notorious for this problem, The correct cure is efi; which is easily within your capabiliites. I design and build my own anlogue efi controllers for automotive applications and you can build yours also. This eliminates the plumbing, the carb heat, and the fuel distribution problems. You don't have to go to efi. You do Have to, and must, reduce the cranking compression pressure. The larger cam will delay closing the intake valve and thus reduce compression. Also, of course, you need to reduce the total ignition advance. A subject initself. I'm apilot also, retired now; and I had the exact same engine problem you did when doing your hot turn-around at the airport, engine vibration increasing rapidly,. becoming shuddering, loss of power; pulling back to cruise throttle setting and going to level flight<(at 25 feet above an enormous log pile for a lumber mill that lay under the departure end of the runway) allowed the engine to smooth out. This occured witha certified aircraft engine using fresh aircraft fuel from the airport. The "hot soak-quick turnaround" is THE stress test for your octane rating. If want to know a lot more about your engine and your project You should call me on the phone, you'll probably get the snswering service, but leave your numbere and a time to call. 808-929-8137 John R. Affleck Ps. If anyone asked me, I'd probably say your engine wasn't "actually detonating", when it threw up the big cht # and ran rough; a chief symptom of detonation is a sharp reduction in egt' which we don't see. Engineers call this "abnormal combustion", and it's almost certainly headingly rapidly towards "heavy detonation", which in turn leads to pre-ignition; a distinct problem; and then you fall down and go boom. In order to avoid the final stage of this process; cut off the side electrode of your (automotive) spark plugs. cut it off with a .040 abrasive wheel in an air cutter or with a cut off wheel in a dremel, even with the near edge of the center electrode' in racing land we call this "un-shrouding the spark". But you'll be doing it to pull the teeth of the dreaded side electrode heating and pre-igniting dragon. The shorter remaining leg has a much different thermal profile owing to the shorter path to the plug body; and I'm sure you'll understand at once. Of course, you have to round off the resulting sharp edges, and wash the very devil out of the plug; to get rid of the abrasive. Which reminds me; nextime you hone your cylinders; and you're ready to use them; wipe the inside of the cylinder with alcohol on a white paper towel; the gray stuff on the white towel is hone abrasive that you were going to install in the engine. Now take a green 3M pot scrubber and scrubb the I.D. of the cylinder by putting your hand inside with the scrubber. Apply yourself; have patience; do it for a while; apply pressure. What are you doing? Profilling the cylinder finish. Flattening the tops of the scratches. And by the way, the angled scratches, so beloved of everyone, are just an old wives tale. The famous 45 degree honing angles, whatever. It's been tested in an engine research laboratory; it's utterly meaningless. You should be able to figure this out; the rings make a labyrinth seal over the tops of the many little grooves under each contact face; they could give a shit what angle the grooves are at. You are not to be blamed for not knowing this; this kind of information is only available in a very few specialized textbooks. Oh and by the way, you faith in Pefect Seal is touching, but thats a brand not a ring design; and I'm here to tell you that Childs and Albert make piston rings; the other people just fool around. What you want if they're made in a size you can use are C&A Zero Gap rings. zero leak down and unbreakable. Literally, unbreakable. Call me and give me a telephone time. I can"t write you a whole book;d and I have a lot more things to tell you.Needless to say, I find it amusing to read about people building engines, including very elevated professionals, and the absurd theories and popular dis-information they're operating on. But you're playing a dangerous game here; and you need some help; it won't be funny if your luck doesn"t hold out, so give me a call and take advantage of whatever part of my education you wish. Cheers, Jack
From: John Affleck
To: Mark Langford
Sent: Wednesday, January 24, 2007 8:08 PM
Subject: Corvair conversion/ engineering
knowledge
Your bigger cylinder project strikes me as strange. Where are you going with this? What are you trying to accomplish? You want a high performance aircraft, get a variable pitch propellor; still not fast enough, go to a gear red. prop. drive; too iffy? too "experimental"; you already broke a crankshaft and experienced in flight detonation; how could a prop drive be too experimental. My point; you're already expermenting and you don't know it. Your smarter than wn. Whinn' you had better answers before you met him then you did after you decided to listen to him. You expressed the thought that electronic ignition was reliable and useful on your volkswagen and that you planned to use it on your airplane . But you ended up with a distributor swith two sets of points inside. Weak ignition is one lead in cause of abnormal combustion' which segues into etc. etc. as above noted. Immediately, you say, I don't have weak ignition! How do y ou know? Are your coils designed for points and condesor operation? Are they designed for a condensor of the value you're using? Why did you think the engine design team at General Motors put the coil on the engine block? As they did on the chevy small block; and all other american stock cars. Because they were stupid and failed to notice that there's a lot of vibration and heat on the engine block? or because they knew something theat you and Wm Winn don"t know? Yeah, I'm afraid it's number two. Get the damn coil onthe engine, nowww. Don't do anything else until you do this. Then conduct ign timing tests by doing ground runups' try to find best power and then back off 9degrees. Find peak egt and back off 100 degreesF. One or the other. The last 7 degrees running up to mean best torque gets y ou 1&1/2 percent torque increase; and practically speaking doubles the peak cylinder pressure and peak temperature. You can't even measure this "loss" of power reliably; but this is the most expensive way in the world to "make power". These are the 7little degrees from hell that have killed more engines than any other single operating factor. You want more power? Fine, I can dig that. But you don't do it by spending your money on bigger cylinders. Go back to your computor simulation,(I use the same program), and look at the volumetric effeciencey and BMEP numbers; that's where your horsepower is going to come from. You yourself noted, at one time, how surprising the large increase in power of the Monza variant was, with it's four symmetrically mounted,vis vis the intake runners, carburetors. You absolutley right; it's very surprising. But you need to study this odd fact untill you understand it. The engineers at GM knew this was the first thing to do to produce the hig her output corvair; because they knew it had fuel distribution problems; the symmetrical carbs solve this problem. There's three things I can tell you about your big cylinder modification; one; the larger bore will have a lower octane rating; two, the modification won"t produce a one to one increase in torque, because the larger cylinder will make the already grotesque valve area/bore area ratio even worse then it is; three; it had nothing to do with breaking your crankshaft,(You keep repeating that you think this was a factor in the shaft failure; it wasn't) It's very important in engineering to only fix the part that's broke; because all human endeavors are characterized by a limited amount of money and time. Aircraft preformance at this point will come from a variable pitch prop; and inexpensive engine mods. The next place to go after that is a reduction drive; (hint: you're never going to get 160 hp by changing cylinders.) E mail me with your phone number, I have way too much to tell you to type it all. Yes I know all the factors involved in designing a reduction drive, and my name is not William. Let's open up a communications channel.Cheers, Jack 808-9298137
From: John Affleck
To: Mark Langford
Sent: Friday, January 26, 2007 8:23 PM
Subject: Internal combustion engines;
Almost random notes; the ten lbs./insq. that you refer to in your lament about your oil pressure, is not an engineering data point. It originated with Smoky Yunick's book about his experiences building chev.V8'S for the nascar circuit in the sixties. Be advised that Mr. Moroso, headf of Moroso performance products, routinely operates his aftermarket chevy. small block with zero oil pressure indicated at idle' and about 40psi at 8000 rpm at the end of the dragstrip. Oil pressure is irrelevant except as a predictor of oil flow rate thru the crank system bearings. Oil pressure per se, is simply irrelevant to the operation of hydrodynamic bearings. However, flow rate is proportional to the square root of the gauge pressure. What you need to do is get rid of the oil filter, and it's plumbing; and replace the lines to the oil cooler with -10 hoses and "hard elbows".Your oil filter is bypassing and supplying unfiltered oil to the engine on take=off/(cold,cool), and it has no function in prolonging the life of your engine. Put an air outlet behind the oil cooler on the fuselage. Sorry, I'm referring to your careful attention to "ten lbs,/psi per thousand rpm", which consideration is unknown amongst graduate engine designers. Mr yunicks remarks appllied to a particularly horrible engine that is no longer used; they have been faithfully repeated thru the magic of plagiarism. Where most of your "Knowledge" comes from. The entire engine performance lanscape is filled horizon to horizon with bullshit. The real ansers have been known and understood since 1929, conservatively. How would you like to have a 650 watt electric heating element in your oil pan to insure that your oil temperatures are high/borderline? Well, not to worry; you already do. The ball and sled rockers need to go away, they are the heating element. But not to be replaced with aluminum rockers, which loaded heavily in reverse stress as they are; have a lifespan, and then they break. Aluminum is a very very poor structural material. The roller rocker you want is called a Pro Magnum rocker and it's made by Comp. Cams. who have a web site and catalog. Have I seen them break? yes. Are the people who sell them to you wonderful people who care more about your lifespan then their plrofits?; No, You can't afford the kind of failure that's inevitable with an aluminum rocker in an airplane. Take heed. I have nothing to sell you. The Pro Magnum rockers are investment castings in stainless steel' are they too heavy? no. They're designed by engineers' not by Wm. Winn. They will not fail. This is what you must concentrate on if you want to play propulsion engineer for a man carrying aircraft; the simple fact that they will not fail; ever. You need race bearings and not the passenger car bearings that you have now; trust me. Look up your part numbers and order them up. You mention that you're going to do breakin with straight 30W; You should never have enything but straight 30W in the engine; plus STP oil additive. These are not opinions; I don't deal in opinions; I'll be happy to explain this reccommendation when you make contact with me. Your opinion that nitrited crankshaft offers an acceptable margin of safety in an environment where a non-nitrided crank broke; is false. Your critical new data is indexing your propellor; which one of your experts got you to do when you were examining your breakage issue. If Wm. Winn did not tell y ou to index the propellor in his book; t hen he is immediately known as a fool and a dangerous fraud. Propellor indexing is required; for instance in the Continental Aircraft Engine cos. family of flat sixes; the procedure is mandated and explained painstakingly in the engine overhaul manual. Please see Charles Taylor, "The Internal Combustion Engine in Theory and Practice", in two volumes by MIT Press. Available at Borders; etc. This is where the engineers at G eneral Motors learned enough to design automotive engines; specifically; this course material; this professor; this is a historical fact. It contains diagrams of air propellor torsion vibrations, and a sobering commentary to the effect, that this is one on the most difficult and problematical engineering problems; the air propellor attached to the internal combustion engine. The Indexing you did is what allows you to operate; unfortunately, the propellor is on the wrong end of the crankshaft. Once again, this is not an opinion. It's possible you can run like this for a long time; I don"t know. But you;ll never have the excess survivability, the big green area betweeen daily operations and the ragged edge of the envelope; that you would have if you stopped feeding the thrust pulses thru the length of the crank to mix and match with the torsional pulses, on their way to the thrust bearing; Which is on the other end of the Crank!808-929-8137 Contact me, cheers Jack.
From: John Affleck
To: Mark Langford
Sent: Saturday, January 27, 2007 6:45 AM
Subject: corvair engine
There aren't usually any book cams; catalogue items that maximise performance for a particular application. Custom
grinds are available and usually produce very significant gains. Your idea that
the overadvanced cam was good because your simulation
numbers went up is incorrect. In this case, of excessive advance or retard
showing good gains, what you should understand the computer is telling you is
its time to re-design the camshaft. Apparently you want your horsepower at 3500
rpm. You plugged in stock manifolds/mufflers, I suppose to duplicate the
factory numbers' ; when I designed this camshaft for
you I elected small tube headers/open exhaust as being more representative of
your application. At a compression ratio of 8.5 to one; more realistic than the
9 .5 you plugged in; Somehow you ignored the 98Oct.
and 99Oct. fuel ratings on your GM test reports; 133hp is available at 3500
with the present disp. and very poor heads; changing to the 140hp head valve
diameters; at 8.5 compression we get 140Hp. at 3500 rpm. This cam can be
ground; it's perfectly feasible. It uses solid lifters; one more set of moving
parts you don't need and don't want are the bits and pieces inside the
hydraulic lifter. Your statement that the output curves would be greatly
affected by the manifold arrangements is false. I realize your parroting what
you've been told; but you might as well know what the facts are. There's no
practical manifold you can put on a corvair engine that will change the peak
torque rpm by even 150rpm. I eliminated the restriction in the intake manifold
that you plugged in; you're not using the stock carbs; but what you are using
may be worse. What you need is four little stubby air valves located and
mounted a la
From: John Affleck
To: Mark Langford
Sent: Saturday, January 27, 2007 4:22 PM
Subject: aerocorvair
More on camshafts and engine performance. I think somebody probably told you that the bigger,140Hp. heads were'nt good for your 3500rpm application; unfortunately, this is completely false.The heads I see described in your GM test report have a higher air capacity, significantly higher, than the ones you have now. What's done with that capacity is up to the engine designer; me for instance. Your computer will quickly teach you this if you allow it to;
the Dyno Sim Pro program may be my only ally here'; but that's all right; you can get 160 horsepower at 3500 if you go find yourself a pair of these heads and this includes 95mm barrels. It's perfectly clear that if you obtain these heads; fuel inject them; and use the correct camshaft you can get 140 Hp. at 3500 rpm., and 8.25 to one Comp. I'll give you the Comp Cams lobe numbers, inter=lobe angle and cam blank number, this is what you use to order the cam made. Typically the charge is the same as a catalogue cam using the same core. This will be a solid tappet camshaft using the same springs you have now. By far the most important thing you can do in your search for horsepower is to obtain a set of these heads. Remember your simulation program. "speaks engine", and so do I. I'm afraid there might not be very many people you can find who understand this matter correctly, but me and your computer outvote everyone else. The 140 hp. quote is for the short block you have now; I hope you can withdraw gracefully from your big bore program; its the wrong thing to spend money on. 808-929-8137 Jack
From: John Affleck
To: Mark Langford
Sent: Saturday, February 17, 2007 6:31 PM
Subject: Aero Corvair 808-929-8137 Hawaiin Standard Time
ref. your page showing the outputs from
your EIS. The spread in EGT's shown here is not
acceptable; assumiing only that I was able to
interpret the colors of the lines properly. This is deeply related to
"in flight detonation", as well as your puzzlement over the less than
ideal results in your page on "tear down/inspection". I am repeating
now; this engine does not have good fuel
distribution;(cylinder to cylinder equality). This is revealed in the EGT spreads. All carbureted aircraft engines share this
characteristic to some degree. There's an interesting site on the web for a
company that has ATC'd a fuel injection install for a
Jacobs radial engine, reading it will give you an idea of the bene's that come from port injection. I repeat, again' that
you yourself commented on the large difference in output obtained with the
From: John Affleck
To: Mark Langford
Sent: Saturday, February 17, 2007 8:01 PM
Subject: fuel injectiion
I forgot to mention two things; one you need to drill holes
in the intake manifold to stick the injectors in. If I can do it; you can
certainly do it. It's not a high precision process; the only requirements are
correct diameter, good surface finish;(which seems to
be a gimme using a low speed portable electric
drill), and a chamfer on top. The injectors are self limiting as to depth; the
hole is not counterbored. They seal with an O ring. Farmers have done this
successfully. HotRod magazine carried a picture of an
Oldsmobile V-8(old kind) that a farmer and his son converted to EFI; They even built their own manifold and painted it up;
actually these conversions are becoming rather common. Also you need a piece of
"fuel rail", from Holley at Summit Racing. This is an extrusion which
you cut to length. it has a round hole in it, through
the length of it, which is correct for tapping 3/8NPTF, which you do after you
cut it to length. Then you locate your injector tops on the bottom of the fuel
rail and mark it and drill through to the fuel hole with a 5/16 drill. Then go
back and drill for the O ring,(counterbore), same as
the bottom. There's enough meat, room, in the extrusion to drill through 5/32
so you can fasten it down to the manifold; or cylinder head; With a STEEL
STRAP; an aluminum strap might vibrate, and then it would break, so use
1/16" galv, strap from the hardware store, say
by 1-1/2" wide for instance. This you invent to suit your engine; you'll
have two of these on each rail with the bottom of the strap screwed to
something. On one end of the engine a crossover is installed, consisting of
appropriate fittings and -6 braided line. At the other
end, there's a fitting and line going back to the fuel pump on one side, and a
pressure regulator on the other side, whose outlet goes to the return line. You
can fake up an OEM regulator if you wish; or you can buy a regulator from
From: Mark
Langford
To: John
Affleck
Sent: Saturday, February 17, 2007 8:44 PM
Subject: Re: fuel injectiion
John,
I
have been working with a EE on a truly impressive fuel injection/ignition
system for about the last year, which I was going to flight test and use
myself, but unfortunately he got super busy with a job he couldn't refuse, and
has basically shelved the project until he runs out of work. So I am
clearly not aversive to fuel injection, but wanted to
iron out the rest of the airframe and engine before I went there. After
400 hours, I'm ready to try it. You also don't have to convince me that
my engine has a fuel distribution problem. I've been saying that since
the beginning. I'm convinced that much of it is due to the Ellison
"carburetor" and hoaky induction system.
Rereading
I
also have two 140 horsepower "dual inlet" heads, but I'm saving
those for some other testing. I now have a "spare" 2700cc
engine that I can ground test things with before moving to the air,
so sure, I'll take you up on your offer of building and testing your
injection system. I also have a few spare heads that I don't mind
putting holes in for injector bosses or other experimentation. I have a
mill and a lathe, so I can probably fabricate the stuff I need to make. I
already have a fuel pressure regulator made for injection systems. Send
it on, and we'll see how it works out...
Mark Langford,
see KR2S project N56ML at http://home.hiwaay.net/~langford
email to N56ML "at" hiwaay.net
From: John Affleck
To: Mark Langford
Sent: Sunday, February 18, 2007 1:46 PM
Subject: corvair conversion
No the fuel distribution problem is not caused by the
plumbing and carburetor; its a function of the
manifold design. In your pages on corvair engines, and test data etc., you have
a reprint of a Hot Rod mag. article, and also your comments on it. Probably,
you thought these improvements only apply to higher RPM ranges. For the second
time, now; this is a false asumption. What the fourhole head gives you is air capacity; what's done with
the air capacity is up to the engine designer. Certainly there can be excess
air capacity; but in this case, at 3300-3600 Rpm that is not the case. What I'm
offering you is a complete development path to your goal; if you refuse to use
your four hole heads; then I can't help you. The delta
40 horsepower that you need to be sure of getting to 200MPH, (as much as I can
understand what your goal may be), will come from; a.)four
hole heads b.)fuel injection
c.) the correct camshaft d.)reduction
of the compression ratio to 8.0 to one Electronic ignition is vitally
important because that, combined with fixing the fuel distribution problem,
will allow you to run lean of peak at cruise;(lean to lean miss, and bump
back), which will go a long way towards making engine safe to use. Repeating;
leaning to Stoich. and
leaning to Peak EGT are both incorrect. Stoich. is the mixture strength where
abnormal combustion/detonation is most easily provoked,(break out your
From: Mark
Langford
To: John
Affleck
Sent: Sunday, February 18, 2007 8:53 PM
Subject: Re: corvair conversion
You wrote:
No the fuel distribution problem is not caused by the plumbing and carburetor; its a function of the manifold design.
I didn't say anything about "plumbing" being the problem, I said "induction system", which I believe covers the manifold as well. You must think I'm a moron. I also know for a fact that a slide carb leads to different mixtures in each leg of a siamesed manifold, and the lean and rich sides swap places at various rpms. It's been proven by everybody that flies a Corvair with a slide carb and split manifold. I'll be the first to agree that the currently common implementation of the intake tubing is not optimal, which is why I started out with a Weber carb mounted on top of the engine, and another reason I'm planning to implement fuel injection.
One reason I haven't replied to your emails is that you seem to twist things around a little trying to make me look like an idiot, and yourself as the brilliant teacher. I don't appreciate that, and can see this is going to painful. Your comment that "I know everything there is to know about engines" pretty much says it all, and that line was in your first or second email. It was at that point that I was convinced that you were on some kind of arrogant power trip, and that any relationship with you was going to be annoying.
What I'm offering you is a complete development path to your goal; if you refuse to use your four hole heads; then I can't help you.
What I said was I was going to save it for later testing, and by that I meant that once the fuel injection is tested on a single port manifold (highly modified, and may have THREE ports, not just one or two) and data points are taken, I'd then modify the 140 heads to a similar configuration, thereby proving the value (or lack thereof) of the bigger valves. I have no qualms about milling the entire manifold log off a pair of 102, 95, or 110 hp heads, but I'm not going to start prototyping on a pair of expensive and hard to find heads just to make you happy. Besides that, larger valves in a Corvair head are a definite liability due to their propensity to drop seats because of the lack of aluminum between and intake and exhaust seats, and should not be undertaken unless there is a real advantage.
I'm not interested in fuel injection as a pathway to squeezing the maximum power of this engine, but instead I'm interested in fuel efficiency, smooth running, and clean combustion chambers. I'm convinced that the Corvair crank is nearing it's limits at the power output we are now asking of it. I don't want a 200 hp version of a Corvair. If I did, I'd turbo the thing and get high altitude capability as well. I don't like being a glider pilot in a plane that's not designed for it, and I'm not going to let anybody force me into that situation again.
This is for climb out; it's probably the only way you can operate this air-cooled engine that was designed for 99Oct. fuel safely on 92Oct.
You keep saying stuff like this, ignoring the fact that I have 400 hours of flying on 93 octane fuel with no problems other than the time the plane was filled with 87 octane on one of the hottest summer days I've ever flown. And this was with a compression ratio of 9.3:1. Do cold, hard facts based on actual experience mean nothing at all to you?
If you want to work with me on fuel injection, that's fine. I don't need any demands "use my cam design, manifold, this, that, and the other, or no deal". Contrary to what you think, you are not the world expert on aircraft engines, their applications, or Corvair engines in particular. If you're not willing to concede that this is my engine and I'll build it the way I want it done, then I don't need your help. I'd rather work the issue myself without the hassle...
Mark
Langford,
see KR2S project N56ML at http://home.hiwaay.net/~langford
email to
N56ML "at" hiwaay.net