well if that is a proper camera, it has a directional mic so that doesn't say much
can't see the vid tho

Quote from Shotglass :

which im pretty sure it is with the profile oriented that way
unless im misunderstanding you

Use a rule. One way it's flexible, one way it's still. With the cheap ones (i.e. in most production engines) it's like two rules in the flexible orientation where it needs to be stiff. A proper conrod - as used in F1, GP2, F3, DTM, or any race series where forged conrods are allowed - has them so the two rules are stiff in the direction that needs to resist bending.

Quote from mcintyrej :

Either I'm explaining it wrong or I've completely missunderstood how the Audi works.

That layout will have an effect on the vibrations (but I can't be bothered to attempt to work out the second and third order vibrations of one, as it takes ages), but not so much the power delivery. The pistons aren't independant, and they don't move independantly. The 4 cylinder still has four seperate bangs, and your 5 cylinder has 5 seperate bangs.

What about this:
...
...
|111|.........|222|............|333|..............|444|
...
...

All 4 cylinder engines do that too. But the firing order is 1 & 3 and 4 & 2, but 1, 3, 4, 2 over 720° of crank rotation.

What a beast, here's an external shot of the same run, as you can see it really is drowning out the chopper.

http://www.youtube.com/watch?v ... tDNrk&feature=related

Quote from tristancliffe :

Use a rule. One way it's flexible, one way it's still. With the cheap ones (i.e. in most production engines) it's like two rules in the flexible orientation where it needs to be stiff. A proper conrod - as used in F1, GP2, F3, DTM, or any race series where forged conrods are allowed - has them so the two rules are stiff in the direction that needs to resist bending.



That layout will have an effect on the vibrations (but I can't be bothered to attempt to work out the second and third order vibrations of one, as it takes ages), but not so much the power delivery. The pistons aren't independant, and they don't move independantly. The 4 cylinder still has four seperate bangs, and your 5 cylinder has 5 seperate bangs.

What about this:
...
...
|111|.........|222|............|333|..............|444|
...
...

All 4 cylinder engines do that too. But the firing order is 1 & 3 and 4 & 2, but 1, 3, 4, 2 over 720° of crank rotation.

I'm not really big into the internals of engines, I've only just got my provisional through the post!

The only reason I'm actually saying what I am is because my dad told me. (sounds a bit childish to always belive your dad but he has rallied many cars before and owned two quattro's in the past, he turbocharged one of them "himself" (not sure what that quite means, bought the turbo and fabricated bits I'm guessing))

http://www.youtube.com/watch?v=AsXTS0hDxjE 1:10 in

Matra V12, that'll do nicely!

http://www.matrasport.dk/Galle ... ds/Misc/03_demo_MS120.mp3

http://www.matrasport.dk/Galle ... ds/Misc/04_demo_MS670.mp3

Quote from 5haz :

What a beast, here's an external shot of the same run, as you can see it really is drowning out the chopper.

http://www.youtube.com/watch?v ... tDNrk&feature=related

i really really hate to insist but if the mic on any camera is directional, even if you had a space shuttle launch behind it would barely pick it up :/

i am NOT saying that the engine is quiet. i am only saying that the fact you can't hear the heli doesn't say much.

besides, heli engines aren't particularly loud anyway.

Quote from mcintyrej :

I'm not really big into the internals of engines, I've only just got my provisional through the post!

The only reason I'm actually saying what I am is because my dad told me. (sounds a bit childish to always belive your dad but he has rallied many cars before and owned two quattro's in the past, he turbocharged one of them "himself" (not sure what that quite means, bought the turbo and fabricated bits I'm guessing))

Nothing wrong with learning from Dad! Anyone who says otherwise either has a Dad that doesn't know anything, or is an orphan

Quote from tristancliffe :

Nothing wrong with learning from Dad! Anyone who says otherwise either has a Dad that doesn't know anything, or is an orphan

Its only wrong when your dad thinks he "knows it all" but really doesn't!

Its quite hilarious when he seriously tries to diagnose medical issues in the family and wonders why the heck he's wrong when they find out the true diagnosis!

Quote from pearcy_2k7 :

http://www.youtube.com/watch?v=AsXTS0hDxjE 1:10 in

That's at Reims that is.



Regarding 5cylinders and 4cylinders, 4can go into 360 exactly, 5 can't. So a 5cylinder engine has to fire the cylinders independantly. Which means increased torque as you aren't missing a stroke. To my knowledge racing 4cylinder engines at least, fire in pairs. That's why they vibrate extremely and seem to idle on a 1-2 basis.

the closest thing to a 'perfectly balanced' engine that i've heard of is honda's V5 in their older motogp bike that is actually a v4 with another single cyl engine stuck on its side.

what you are guys talking about, however, "5 cylinders all independed" sounds complete yahoo to me.

got an animated gif? something? anything? i can't seem to find anything online.

Quote from BlueFlame :

4can go into 360 exactly, 5 can't.

WAT

Quote from george_tsiros :

the closest thing to a 'perfectly balanced' engine that i've heard of is honda's V5 in their older motogp bike that is actually a v4 with another single cyl engine stuck on its side.

what you are guys talking about, however, "5 cylinders all independed" sounds complete yahoo to me.

got an animated gif? something? anything? i can't seem to find anything online.

This isn't an Inline engine, but it still proves the theory.... not...
http://mechanicalgalaxy.blogsp ... sternmotor-animation.html

Quote from BlueFlame :

4can go into 360 exactly, 5 can't.

erm..... yes it can. It's 72. And even if it couldn't (say with 7 cylinders) the rotation of a driveshaft is an analogue value. It's not like it flicks from position to position in 1 degree intervals.

Quote from Crashgate3 :

erm..... yes it can. It's 72. And even if it couldn't (say with 7 cylinders) the rotation of a driveshaft is an analogue value. It's not like it flicks from position to position in 1 degree intervals.

Oh, well my maths failed, at least I'm honest and didn't use the windows calculator so I can wing it and pretend I know :P. I thought I knew, but nope. Not even I can argue with mathematics!

Quote from BlueFlame :

That's at Reims that is.



Regarding 5cylinders and 4cylinders, 4can go into 360 exactly, 5 can't. So a 5cylinder engine has to fire the cylinders independantly. Which means increased torque as you aren't missing a stroke. To my knowledge racing 4cylinder engines at least, fire in pairs. That's why they vibrate extremely and seem to idle on a 1-2 basis.

But it isn't independant - they are all connected to the same crank, and therefore go up and down in the same sequence, firing every 720 degrees. Yes, you get more bangs per rev, but if that was the be all and end all we'd all be driving W1000 engines.

Next person to use the word independant in this thread, with regards 5 cylinder engines gets a cookie, and has to eat it.
a poisoned cookie

Quote from tristancliffe :

But it isn't independant - they are all connected to the same crank, and therefore go up and down in the same sequence, firing every 720 degrees. Yes, you get more bangs per rev, but if that was the be all and end all we'd all be driving W1000 engines.

Next person to use the word independant in this thread, with regards 5 cylinder engines gets a cookie, and has to eat it.
a poisoned cookie

We are talking about during 1 full rotation of the crank. Of course each cylinder fires more than once when the engine is running.

what does 'independent' cylinders mean, anyway!!!???

Quote from tristancliffe :

Use a rule. One way it's flexible, one way it's still. With the cheap ones (i.e. in most production engines) it's like two rules in the flexible orientation where it needs to be stiff. A proper conrod - as used in F1, GP2, F3, DTM, or any race series where forged conrods are allowed - has them so the two rules are stiff in the direction that needs to resist bending.

i think you may want to look up the moment of area for a double t beam cause right now youre making yourself look like you failed mechanics for 12 year olds

apart frem the much more complicated ones you can find on wikipedia the simplest rule of thumb that i found in some german lecture is that the stiffness in the direction you claim the beam is solid is only about 2/7th of the one in the direction that its actually stiff in (ie the one standard conrods are built for)

The Mazda Rotary Engine.




Yeah. You heard me.

f430, this is just pureseks

Best Engine hands down is the honda K series only followed by they're B Series

Quote from Shotglass :

i think you may want to look up the moment of area for a double t beam cause right now youre making yourself look like you failed mechanics for 12 year olds

apart frem the much more complicated ones you can find on wikipedia the simplest rule of thumb that i found in some german lecture is that the stiffness in the direction you claim the beam is solid is only about 2/7th of the one in the direction that its actually stiff in (ie the one standard conrods are built for)

I think we're getting wires crossed. When I get out of bed, and before I pack my race gear and load the race car, I'll draw a little diagram and draw some pictures. Hell, I might even do the second moment of area calculation to show what mean.

But it's relatively simple, and even the janitors in engine shops know that cast conrods are wrong. If you can't see it, either you don't understand engines very well, or German engineering is on the decline (or I'm doing a terrible job explaining what I mean on a phone)

Pictures to come in a bit...

Quote from Intrepid :

Parilla 125 Sudam. Max HP 55 approz 10-15kg



Italian and simple = beatiful

If thats the old air-cooled JICA or ICA engine, it only has a 100ccm.
The new KF3 ones has 125ccm watercooled.

This is what we're talking about. Wrong on the left. Correct on the right.

Sorry, just realised what the time is, so don't have the chance to draw and calculate stuff right now... Maybe later.

Quote from Dennis93 :

If thats the old air-cooled JICA or ICA engine, it only has a 100ccm.
The new KF3 ones has 125ccm watercooled.

lol no its a Parilla Sudam..... look it up! 55hp with dual carb and tuning! http://buller.net/cat--125cc-P ... am-Engine--eng_sudam.html

The Formula K motors used to have 135cc