Author Topic: venturi length (Read 9550 times)

Bootlegger · « **on:** January 13, 2017, 05:30:38 PM »

I have noticed on some of the foreign made engines that the venture is longer than other engines. What effect does this have on the way that an engine performs? Does this make the engine have more torque, or what other advantages does this give?

Thanks

Tim Wescott · « **Reply #1 on:** January 13, 2017, 06:57:03 PM »

Your venturi should be a minimum of three inches long. Please have one custom-made for your plane, and then post pictures.

Tim Wescott · « **Reply #2 on:** January 13, 2017, 07:00:16 PM »

In theory a right-length venturi will have a bit of a supercharging effect on the engine (see high-rise manifolds for cars, for instance). I don't know if that works for our engines, though, and maximum power isn't what you want for stunt anyway.

Probably more important, on a typical 2-stroke engine the intake port opens when there's still a bit of pressure in the crankcase, and closes after. This makes the engine want to "spit back" a bit of fuel/air mixture, particularly when we're using a non-stunt engine for stunt. A longer venturi helps contain this spitting back (as does a bit of fine nylon mesh over the venturi).

M Spencer · « **Reply #3 on:** January 13, 2017, 11:34:08 PM »

You Could Try various length Velocity Stacks , ON the Intake !

Your actually aiming for maximum ram effect , AT a Certain r.p.m.s , Variable to suit Tourque/ rpm requirement , for differant tracks or conditions .
Though it'd only be a percent or so power differance , Way Out ( of sync. ) could get stutter etc . probly effects the ' switch ' 4-2-4 .

Also Long Past Jet can prevent spit back / fuel expelling from intake . Possable in the 4 stroke mode perhaps .

One Thing that Bugs Me is that the 4 - stroke blokes havnt gone to ' tooned lengths ' for their Zorst Pipes .
The Old Hot Rod maximum was a crayon or paint line , down the pipe .
Itd scorch first at the wave length peak , tho actually youd cut the pipe at say the third Zap Out , Going for Tourque .

Pressue Cycles apply to the suck and the blow . One Intake per Cylinder is necessary for Optimiseation .

Theres actually negative pressure zones in a Ex System , to tap into for vacume . When ' Its on the Boil ' .

The book there ( By Phil Irvine ) should have the rudimetarys of Tuned Intake length Vs RPM for Two Strokes . Like the BSA Batman & Vespa .
The Forular Provided should be applicable .

M Spencer · « **Reply #4 on:** January 13, 2017, 11:42:27 PM »

Technically theres advantages in ' laminar flow ' with a ' trumpeted ' intake - With NO Sharp edges at the outer extremety . ( Should be a Full Radius )
A sharp Edge can cause turbulance and ' choking ' / Shock wave Constriction .

So that there snotter has a Real Intake !

Thus ,

Brett Buck · « **Reply #5 on:** January 13, 2017, 11:50:37 PM »

You want the inlet end to be as long as practically possible to better act as a flow straightener. I asked Dub Jett and Richard Oliver to make me a longer intake than the stock Jett venturi and even ~1/8" made a noticeable improvement in the (already excellent) run symmetry.

I think most of us can calculate the length of a half-wave resonator at 166hz, so any practical application of intake tuning is not, charitably, plausible. There was a lot of discussion of intake tuning back in the supposed "good old days" of 40FSR and the other "schneurle-of-the-month" engines and one trick was the application of magical "5 degree taper" long conical venturi supposed to tune the intake. It did make a difference in some case, but I am virtually certain that the effect was flow straightening, nothing to do with intake tuning. I would expect a similar effect with an air filter on a different, shorter venturi. The last thing you want, for stunt, anyway, is a short trumpet and any sort of attempt at super-smooth streamlined flow. I guarantee that it will not be super-smooth at all AoA and that will make it vary with maneuvering, both in terms of flow and flow restriction, but also in the way it atomizes the fuel.

Brett

Brett Buck · « **Reply #6 on:** January 13, 2017, 11:57:31 PM »

Quote from: Matt Spencer on January 13, 2017, 11:42:27 PM

Technically theres advantages in ' laminar flow ' with a ' trumpeted ' intake - With NO Sharp edges at the outer extremety . ( Should be a Full Radius )
A sharp Edge can cause turbulance and ' choking ' / Shock wave Constriction .

   Theoretical advantages in steady-state flow VS restriction. If we flew stunt contest with engines bolted to a test stand in dead calm conditions and no propellor flailing away 1/2" in front of it, then yes, it might be an advantage. In flight, you don't care about that for stunt, you can get arbitrary quantities of power, far more than you could possibly use, from even a 40. But you do care a lot about it running the same through the maneuvers.

   And, as above - you *want* turbulence to mitigate flow variation with AoA. We put turbulation devices on there *intentionally*.

   Brett

Chuck_Smith · « **Reply #7 on:** January 14, 2017, 07:12:09 AM »

On a naturally aspirated engine the longer intake creates in more low-end torque, but it has nothing to do with the Venturi. It's mostly due to air having mass. If you look at carbureted racing engines (which have Venturis) the Venturi is at the front the engine intake and then the length of the intake risers after the Venturi gets tuned. A straight line or road racing motor will have long risers, NASCAR engine built for Talladega will have short ones. (Edited to include two-stroke outboards which are very relevant to what we do with CLPA engines.)

At high revs a longer intake becomes a horsepower robber. For a CLPA engine at a fairly steady 10K RPM the only non-placebo affect I've found to the longer Venturi is that it's easier to choke the damn thing through the hole in the cowl. I might be persuaded to accept that the longer Venturi gets better incoming air into the cowl too, because the opening isn't buried down under balsa but directly into the incoming air.

But it's not like we live in a day and age where stunt engines are underpowered and won't run consistently. The best stunt engines ever made are readily available today. We're living in the best days ever of powering a CLPA ship. (Or you can toss your man-card onto the fire and go electric.

)

Generally speaking, since air has viscosity the longer the Venturi inlet the higher the losses will be. If the Venturi was infinitely long the engine wouldn't run. On the other hand, some old-school engines like the Fox .35 and the Testor's .35 and .40 had short, bell-shaped cast Venturis and run great.

And don't forget, for non-sprinkler Venturis, we have about a .250" hole through which we pass a .125" tube...so the real Bernoulli effect is from the restriction caused buy the spray bar itself, not from tapering the intake. Others may have different information, but the original use of a taper seems to come from using interchangable inserts into the same machined hole in the casting.

The spray bar is placed at the base of the intake in order to keep it about half an inch above the mounting rails so it will have the same suction head inside or outside with the standard 1" thick stunt tank. If we didn't have this restriction it would be a lot of fun to try to tune the intake riser.

I've seen quasi-dissertations on Venturi intake length for stunt, and then in the next post read to put a piece of stocking over the intake to tune the engine run.

Sharp edges? Meh, many, many, trophies where won with the venerable OS.35S and it's sharp Venturi.

IMHO, YMMV

Brett Buck · « **Reply #8 on:** January 14, 2017, 10:48:30 AM »

Quote from: Chuck_Smith on January 14, 2017, 07:12:09 AM

Generally speaking, since air has viscosity the longer the Venturi inlet the higher the losses will be. If the Venturi was infinitely long the engine wouldn't run. On the other hand, some old-school engines like the Fox .35 and the Testor's .35 and .40 had short, bell-shaped cast Venturis and run great.

This is still considering the flow restriction and efficiency to be the critical issue. I don't think that matters at all in any practical situation in stunt, as long as you can stuff a piped 75 into a 625 square inch airplane and be able to control it. That will suck the chrome off a trailer hitch, and David's current engine setup uses a venturi the same size as we run on a 20.

What does matter is the way it runs in the maneuvers and specifically the corners, and the difference between insides and outsides. If that is the problem, anything you can do to make it insensitive to the external flow field is to the good. I have to say, between David and I, almost the only things we have changed significantly over the last 10-15 years have been associated with the intake and carburetion.

On that topic, there are two factors that affect the way the engine draws fuel, and the vacuum from the venturi is only one half of the equation. Once we had spigot venturis and diffusers, that problem was effectively solved. The other half is how hard it is to draw fuel through the plumbing, and we have found substantial improvement in that area, as well.

Brett

Chuck_Smith · « **Reply #9 on:** January 14, 2017, 12:11:27 PM »

Quote from: Brett Buck on January 14, 2017, 10:48:30 AM

...I don't think that matters at all in any practical situation in stunt, as long as you can stuff a piped 75 into a 625 square inch airplane and be able to control it. ...
Brett

Can I have an "Amen!" ?

There is no replacement for displacement.

Sometimes I look back at the .35 powered Nobler-derived ships we flew an wonder how in the heck we did it. Seems like we were always one click of the needle valve away from disaster.

Chuck

Brett Buck · « **Reply #10 on:** January 14, 2017, 12:46:35 PM »

Quote from: Chuck_Smith on January 14, 2017, 12:11:27 PM

Can I have an "Amen!" ?

There is no replacement for displacement.

Sometimes I look back at the .35 powered Nobler-derived ships we flew an wonder how in the heck we did it. Seems like we were always one click of the needle valve away from disaster.

They designed, trimmed, and flew it around the limitations they had. That's why it has a tiny thin wing and turned like a 18-wheeler on a go-kart track. That why, if I were dictator of stunt, I would get rid of Classic, Super 70's, and Nostalgia 30 entirely, and replace it with an event where you can design and build your own airplanes, but you have to use a period engine setup with period-like props. I can virtually guarantee that the airplanes would end up looking about the same as they did back in the day. The only real question is where you put the cutoff - somewhere around 1960, before they discovered the Veco 45.

Those guys were not stupid, for the most part, the good guys then were at least as competent as we are now, so they came up with the best solution they could pretty quickly. Unfortunately, some/many people figure that *nothing* should be different even now, and follow the rules of the 50's with religious fervor.

Now, as then, you don't have to outrun the tiger, you just have to outrun the other guys.

Brett

RandySmith · « **Reply #11 on:** January 14, 2017, 01:58:05 PM »

Quote from: Bootlegger on January 13, 2017, 05:30:38 PM

I have noticed on some of the foreign made engines that the venture is longer than other engines. What effect does this have on the way that an engine performs? Does this make the engine have more torque, or what other advantages does this give?

Thanks

Done tons of research on this, and not all depends solely on length, but the ratio is 3 to 6 times the diameter of the hole, depends on engine, many other things will affect that ratio, like crank timing, duration, when it closes, intake timing, etc....RPMs play a very large part on this with some engines, others, not so much , also you can make one too long and kill off the power, Tall venturie slow the cycling while short ones of exact same diameter, many times speed up the cycling.
Shape of the inside is not really critical on restrictions, but is much more important on true venturies .

Randy

Tim Wescott · « **Reply #12 on:** January 14, 2017, 02:50:23 PM »

Quote from: RandySmith on January 14, 2017, 01:58:05 PM

Done tons of research on this, and not all depends solely on length, but the ratio is 3 to 6 times the diameter of the hole, depends on engine, many other things will affect that ratio, like crank timing, duration, when it closes, intake timing, etc....RPMs play a very large part on this with some engines, others, not so much , also you can make one too long and kill off the power, Tall venturie slow the cycling while short ones of exact same diameter, many times speed up the cycling.
Shape of the inside is not really critical on restrictions, but is much more important on true venturies .

For those of us who are still flying 46LA's, is there much value in making up different-length venturis and trying them out? Or is that just a waste of time?

RandySmith · « **Reply #13 on:** January 14, 2017, 03:13:11 PM »

Quote from: Tim Wescott on January 14, 2017, 02:50:23 PM

For those of us who are still flying 46LA's, is there much value in making up different-length venturis and trying them out? Or is that just a waste of time?

The stock size venturie height seems to work very well, and I have tried them taller, lot taller and really tall, you just need to make the tall ones larger inside ID to run the same
There is a noticeable improvement using a PA NVAs , but remember you MUST run a larger ID with an Enya ST or PA NVA
If you can find any Bruline rubber filter holders and filters, that also very much worthwhile, if not use 1 layer panties hose

Randy

Bill Johnson · « **Reply #14 on:** January 17, 2017, 01:57:24 PM »

Quote from: RandySmith on January 14, 2017, 03:13:11 PM

If you can find any Bruline rubber filter holders and filters, that also very much worthwhile, if not use 1 layer panties hose

Randy

Does that help "make it insensitive to the external flow field"? It would make sense.

RandySmith · « **Reply #15 on:** January 17, 2017, 02:07:22 PM »

Quote from: Bill Johnson on January 17, 2017, 01:57:24 PM

Does that help "make it insensitive to the external flow field"? It would make sense.

NO it helps in this way, both keep the soft sleeve material in good shape , I have seen about a thousand that have many flights, and ones with filters are in much better shape, and it also keeps some of the sand dirt debris out of the engine, the BRULINE filter is also taller and trumpet shape, which helps, with "some" engines keeping fuel in them, and not letting it spill out of the top of the venturie, others don't need it near as badly as some, I was speaking of 1 layer of panty hose, you will need to add additional layers to make the venturie "act" smaller

Next thing I would like to test is L shaped intakes, I have rubber intake filters that are "L" shaped so you can run them , into the wind, pointing outboard, or pointed inboard
, I have a good idea what will be the results, but testing will verify
Randy

RandySmith · « **Reply #16 on:** January 17, 2017, 02:11:30 PM »

additional info, if you find Bru Line filtrs, the Black coarse filter does not change much of anything on the run, the fine green filter makes the venturie "act" like its a few thousands smaller.
Panty hose under the Bru Line filter makes the venturie act even smaller, and also helps stop fuel from going out of the top of the venturie, on engines where that is a problem

Randy

Ognyan Kumchev · « **Reply #17 on:** January 07, 2021, 06:49:35 AM »

Quote from: Bootlegger on January 13, 2017, 05:30:38 PM

I have noticed on some of the foreign made engines that the venture is longer than other engines. What effect does this have on the way that an engine performs? Does this make the engine have more torque, or what other advantages does this give?
Thanks

I myself do use long '"ventures''. As long as opening diameter I use is constant this is rather a nozzle or a sleeve. About sizes later on. Tube theory says , at an experiment like this. Imagine a tin can about a gallon volume. Make a round hole near the bottom about 0.3 inch diameter , sharp and clean tin edges of this hole/orifice. Plug this orifice, fill this can with water, unplug the orifice and measure how long time it will take the water to flow out through this orifice. Then prepare a piece of tube same inner diameter , long about 6 times the diameter - this makes 0.3 x 6 = 1.8 inches and mount it to replace the formerly made sharp edged orifice. Then fill the can again and measure how long time it will take the water to flow out through this tube. The time should be about 30% less. This less time is in effect between pipe length 4 to 11 times the diameter . Smaller length is not enough the water flow to get organized, longer length causes too much friction loss. So. a sleeve 5 to 7 times the diameter seems fine. Measured from where the spray bar is located.
Else. Theory also says every change of orifice opening area is a resistance to the flow. So ,considering a spray bar diametrical, it is better to change the area as little as possible. That is why I use an oval shaped spray bar . As long as a cylindrical and thin one is unpractical for strength considerrations.
Else. Best suction is believed to be when the fuel outlet orifice of a cylindrical spray bar is about ten degrees turned below the side position. I believe it is not hard to consider where the fuel outlet orifice should be at an oval shaped spray bar , or when two fuel outlet orifices are used at one oval shaped spray bar.
All this is what I myself use. Please let me know if anything may be considered better.
Ognyan.

Howard Rush · « **Reply #18 on:** January 07, 2021, 01:26:12 PM »

Quote from: Chuck_Smith on January 14, 2017, 07:12:09 AM

Or you can toss your man-card onto the fire and go electric.

Hey, you guys are the ones with the panty hose.

Chuck_Smith · « **Reply #19 on:** January 09, 2021, 02:55:02 PM »

Quote from: Howard Rush on January 07, 2021, 01:26:12 PM

Hey, you guys are the ones with the panty hose.

Howard,

What matters isn't that we use pantyhose, the important part is how we acquired it.

Paul Smith · « **Reply #20 on:** January 11, 2021, 11:58:20 AM »

In order to create suction and strong fuel draw you need to bring in all the air you can and neck it down at the venna conncocta. So any air filter will reduce the intake of air and thus the suction. That's one reason why serious competition engines never have air filters. The only exception is dune buggies and dirt bikes that really need filters.

Of course if you have power & suction to spare you can afford to filter out some air.

Brett Buck · « **Reply #21 on:** January 11, 2021, 11:16:12 PM »

Quote from: Paul Smith on January 11, 2021, 11:58:20 AM

In order to create suction and strong fuel draw you need to bring in all the air you can and neck it down at the venna conncocta. So any air filter will reduce the intake of air and thus the suction.

How does a choke work? How does putting your thumb over the venturi work? Seems like has tremendous suction with no flow at all.

Rhetorical questions, of course. The answer is that only a fraction of the suction is due to Bernoulli effects, the rest is due to upstream flow restrictions, meaning, also, that adding a restrictive filter (or your thumb) generally increases the suction, rather than reducing it.

Brett

Dave Hull · « **Reply #22 on:** January 12, 2021, 01:20:19 AM »

Yeah, I remember an old chivvytruck I had to drive when I was a kid. The windshield wipers were driven off the manifold vacuum. It was an early version of intermittent wiping--if you wanted them to move, you took your foot off the gas. So in a heavy rain storm it all worked out ok. First you stomped on the gas to go, then you dropped off the petal to wipe. Kind of a rhythm thing, tapping your foot, and to the other drivers maybe it looked like galloping. So you never got going fast enough to hydroplane. It was a feature.

If you talk to engineers about engine design they will always include a benchmark of WOT--Wide Open Throttle. At that point, with no restrictions by any controls on the inlet airflow, you will get the least vacuum but highest flow. And still the fuel goes in.

The bottom end of the engine is a pump. It will draw air; that's not an issue. But if your spraybar setup is marginal the fuel delivery into the airstream might not be as consistent as you'd like for an engine that is just sipping fuel. A pee tube works pretty well, but a side dribbler might not be the best choice for some circumstances. I would imagine that a filter actual catches some of the excess fuel and provides an additional method of atomizing it. It is enlightening to look inside the toilet bowl on the front of a speed engine when it turns up on the ground. I've seen the fuel blobs dancing around in there like crazy. WOT, baby!

I wouldn't worry so much about the venus concubus, which I think Botticelli came up with back in the day when he was watching the orchestra blowing their horns....or something like that.

The Divot

Brett Buck · « **Reply #23 on:** January 12, 2021, 09:42:57 AM »

Quote from: Motorman on January 12, 2021, 07:54:07 AM

Will we ever figure out the venturi?

It's been figured out (for any practical purpose) for a long time, problem is, people don't want to believe the answer because it conflicts with their pre-conceived notions. Just like almost everything else in stunt.

Moreover, also like most things in stunt, about the time we figure it out, something fundamentally different comes along and displaces it.

Brett

FLOYD CARTER · « **Reply #24 on:** January 12, 2021, 01:39:08 PM »

Duke Fox was well known for experimenting with many engine configurations, modifications to "improve" the stunt engine.

Yet, the lowly Fox 35 stunt had a short, almost vanishing venturi.

Surely, Duke had experimented with venturis of all sorts, and yet the Fox 35 is what it is.

If we credit Duke with exploring all options, we have to conclude that venturi length isn't all that important.

DISCLAIMER> I do not own any Fox motors, nor am I planning any such thing in the future.

Brett Buck · « **Reply #25 on:** January 12, 2021, 02:41:14 PM »

Quote from: FLOYD CARTER on January 12, 2021, 01:39:08 PM

If we credit Duke with exploring all options, we have to conclude that venturi length isn't all that important.

So, if it wasn't on a Fox 35, it isn't worth anything? Duke Fox didn't do anything relevant in the field of stunt engines since 1948, and the few attempts the company made - long after he was gone - were 10 years out-of-date the day they hit the market.

Brett

Chris Wilson · « **Reply #26 on:** March 21, 2021, 06:52:19 PM »

Quote from: Bootlegger on January 13, 2017, 05:30:38 PM

......what other advantages does this give?

Thanks

Added length can be used as a protective device and witness the so-called " Dork tube" on combat models that are made flexible enough to fold over upon impact thus preventing dirt ingress that would otherwise damage an engine.
Chris.

Chris Wilson · « **Reply #27 on:** March 21, 2021, 08:45:08 PM »

Quote from: Brett Buck on January 13, 2017, 11:50:37 PM

I think most of us can calculate the length of a half-wave resonator at 166hz, so any practical application of intake tuning is not, charitably, plausible.

Brett

Hi Brett,
Have you considered a side branch resonator much like the RC boost bottle?
Obviates length issues but I am not sure what exactly these thing do, I know the claims in a throttled environment but with a fixed throttle .... Hard to envisage what advantage they might have.
Chris.

Curare · « **Reply #28 on:** March 22, 2021, 06:00:39 PM »

Quote from: Chris Wilson on March 21, 2021, 08:45:08 PM

Hi Brett,
Have you considered a side branch resonator much like the RC boost bottle?
Obviates length issues but I am not sure what exactly these thing do, I know the claims in a throttled environment but with a fixed throttle .... Hard to envisage what advantage they might have.
Chris.

In my opinion the advantage is taking money off off slow-learning RC car types.

Until I see some data, I'll consider it a waste of time

Chris Wilson · « **Reply #29 on:** March 23, 2021, 12:19:03 AM »

Quote from: Curare on March 22, 2021, 06:00:39 PM

In my opinion the advantage is taking money off off slow-learning RC car types.

Until I see some data, I'll consider it a waste of time

Plenty of data about these on two stroke motorcycle engines, notably Yamaha.
But they all seem to offer a slight improvement filling in midrange power deficiencies.
A fixed throttle has no range hence my doubt about them for stunt use.

Chris Wilson · « **Reply #30 on:** March 23, 2021, 04:42:29 AM »

Quote from: Curare on March 22, 2021, 06:00:39 PM

In my opinion the advantage is taking money off off slow-learning RC car types.

Until I see some data, I'll consider it a waste of time

Greg, knock yourself out.
http://www.dragonfly75.com/motorbike/YEIS.html

Brett Buck · « **Reply #31 on:** March 23, 2021, 03:40:55 PM »

Quote from: Chris Wilson on March 21, 2021, 08:45:08 PM

Hi Brett,
Have you considered a side branch resonator much like the RC boost bottle?
Obviates length issues but I am not sure what exactly these thing do, I know the claims in a throttled environment but with a fixed throttle .... Hard to envisage what advantage they might have.
Chris.

No, we have plenty of control over it with just the exhaust. Recall that the point of the exercise is to kill the excess power, rather than make more of it. I have considered the use of a plenum (tuned or not) before the metering to, just like the longer intake and diffuser, reduce the effects of the changing direction of the external flow field.

Note that a "side branch resonator" is overdetermined - a resonator is a resonator, no one ever said you had to have a straight line with conical tailcone, or have the flow direction aligned with the direction of the gas flow. Whistles, flutes, and jugs make resonances, too. A jug (as in "hillbilly jug band" per my upbringing) is a good analog of your side-branch resonator.

Brett

Chris Wilson · « **Reply #32 on:** March 23, 2021, 04:42:17 PM »

Quote from: Brett Buck on March 23, 2021, 03:40:55 PM

No, we have plenty of control over it with just the exhaust. Recall that the point of the exercise is to kill the excess power, rather than make more of it. I have considered the use of a plenum (tuned or not) before the metering to, just like the longer intake and diffuser, reduce the effects of the changing direction of the external flow field.

Note that a "side branch resonator" is overdetermined - a resonator is a resonator, no one ever said you had to have a straight line with conical tailcone, or have the flow direction aligned with the direction of the gas flow. Whistles, flutes, and jugs make resonances, too. A jug (as in "hillbilly jug band" per my upbringing) is a good analog of your side-branch resonator.

Brett

Hi Brett,
I know that the point of the exercise is to kill off excess power rather than make more of it and run on a negative power slope.

Draw the parallel to tuned exhaust pipes or really anything else in 'tune.'
The original thinking came from application, racing motorcyles wanted to go faster - all of the hard work was done in this application.

Then along came some original thinking in 'this' application to operate the engine beyond the state of tune as a limiter.
The same can be said of resonant intakes, in this application it may be practical to operate in exactly the same way as a pipe, being that of a limiter or more precisely put place the gain where its needed to make where its not more pronounced - or exaggerate and more highly polarise the load change.

Also added volume below the jets and before valving has been proven in the Team Race world to create better fuel atomisation.
I will look this up again but the name De Riddier comes to mind as the inventer of such a system and it was promptly banned, and thats about as good a clue to its effectiveness.

I just think that not enough effort and research has been placed on resonant intakes primarily because everyone thinks length, nah that aint going to work because of the practicalities of housing and containing a workable length.
But plenums side step the issue because they primarily work on volume and that volume can be remotely located.

Interesting topic, considering lengths and volumes as the whole two stroke concept is a resonant system and when you consider that it only has 3 moving parts it is paradoxically and overwhelmingly complex to fully inderstand.

Chris.