frets24

My Feedback: (15)

Hey Rev,

Nice new toy, but don't count yourself out of the family...you've been a wonderful, helpful and enjoyed voice here in the group and like a retired soldier; once you've served you're always one of the family!

Cheers!!

BJ64

Don't have any/can't get any.

The gaps in the cut 90's seem to have silver-soldered shut ok.

Here's a makeshift test fit....

BJ

SrTelemaster150

Looks good. Too bad it's so hard to get those fitting there. They are very common here. Any Home Depot, Lowes or local well stocked hardware store would have them. It looks like the 3/8" branch "T"s would work like a charm.

BJ64

Yup - rare as rocking-horse doo doo down here.

So is anything above 3/4". And forget the 3/8 T's. Not a snowballs chance in hell.

So I had to make do with what I could get my hands on. The 1m length of 25mm (1") tube was about 20 bucks. The elbows/joiners 25. I scored a 1m length of what I thought would be 8mm I/D tube for a further 20. Only trouble is, the I/D was about 7mm, so the standard ASP headers wouldn't slide into it.

End result was a cobbled-together test piece with the headers inserted directly into the "pipe" at the joiners. I think I might be able to fashion something more useful out of the thinner pipe - maybe turn the O/D down in the lathe so that I can make my own flared-end header pipes.

All in all, it's turned out to be a pleasing little project. I'm not an engineer's bootlace, so getting it this far has been a fun and quite rewarding challenge.

Light was fading fast, and I just had to hear what this contraption sounded like. So I fudged some header entry points and pushed it all together and on to the motor for a quick test run.

It didn't quite have the deeper note I was hoping for. In fact, it was rather quiet - no real bark at all.

I might close-over the current header entry's and see what it turns out like with them hitting the "collector" at the midpoint along the straight sections. Nothing has been soldered-up yet apart from the cuts in the elbows...so I'm pretty much free to experiment a bit more. If it doesn't turn out the way I wanted it to, no harm no foul - the Keleo shouldn't be all that far away.

Here's what it looked like for the test run...

BJ

SrTelemaster150

The midpoint in the existing straight sections will be a smaller base circle. Your entry on the center of the el makes for the smallest overall outside dimension.

You can make longer straight sections to expant the base circle.

tim750r

How big is the outlet BJ? Can't see it in the photos...IIRC the outlet cross-section on the Keleo job is bigger than the cross section of the ring.

Reverend

My Feedback: (3)

What a nice thing to say Thank you!

...and I have a feeling there will be another FS400 some day. I really like the way the new ones are looking

But for now its the stearman with the Evo, the Zero with the Kolm and the next review Model is that lovely Hangar 9 Beaver 30cc! Really like that one... Imagination running wild with bush wheels, Landing lights and the works!

BJ64

It's a 35mm long 8mm wide slot milled into the rear of the straight section between the left hand cylinders in the front-on photo.

BJ

tim750r

I'm only guessing as I know very little about exhaust design, but maybe that's restrictive?

35x8=280 sq. mm, whereas a 1" pipe is approx. 506 sq. mm

Kmot

My Feedback: (24)

You get an "A" for Ingenuity, and an "A" for Effort.

But I am afraid you get only a "C" for Application.

No wonder it's quiet. I'm surprised it even ran.

Take out one of those straight pipes and insert a "T" fitting so that you have a proper exhaust outlet and then give it another test. And yes, do not jam the straight pipes in too far or that will create a lot of back pressure on each cylinder.

BJ64

The straight pipes into the 'collector' are only a temporary measure, and I made sure they were poked in only about half way.

The 10mm copper tube I got wont allow the supplied headers to slip inside them - and, of course, the headers are far too long anyways for this setup... and I don't want to cut them because my Keleo should be along shortly.

But I will still persevere with the 1" hack pipe in the mean time.

That slot I've milled into one of the straight sections is roughly equal to the same outlet size as all 5 headers combined - and they don't all fire at the same instant, so I would have thought it had plenty of escape to let it breathe... (?)

BJ

SrTelemaster150

It's not so much the lack of breathing as it is the muffling that the small outlet causes. it sounds (no pun intended) like you have created an effecient muffler.

BJ64

Small??

Hell - I can make that sucker as big as I want.

Was thinking more along the lines of having one each side - for outlets into each of the TopFlite FW190's 'exhaust ports'.

Soooo..... how big do you guys reckon I should go?

As I mentioned earlier, only the knicks in the joiners have been soldered-shut yet. The rest is still in "trial mode" - so I can pull it apart and make exhaust outlet mods etc.

BJ

Carosel43

I am loving the half built nature of this device. if lego was made from copper pipe then this is what would result. don't like it?? take it to bits and make it again!! the big thing that no one seems to have pointed out is that you score a big F on this project as there is no video for us to watch

Regarding the 'suffocation' of the engine the easiest test of that will be if the rpm you get with the ring is the same as without. if you get it right you may even get more rpm!!

SrTelemaster150

While I like the idea of having the outlets @ the FW 190A scale locations, if you are after a deep sound, I think 1 large outlet would be more likely to achieve that.

BJ64

Bugger about the "F" then...

The truth be known... I was uber-conscious about that...and got the video camera out to get some pic/sound of it running for you blokes.

Alas... I found out that the reason it pissing fuel/oil all over the place on the first tankful was that the choke managed to click itself shut on me (probably something I did while trying to beat the failing daylight in order to get at least one fire-up after a long day on the gas-axe/lathe/mill/mitre-saw).

Which probably accounts for the disappointing less-than-a-roar sound I got out of it. But... it started on the first flick of the lekkie Align starter.

After the tank refill, I could not get it started again. I'm guessing here that I could have really fouled the glowplugs up with masses of oil and crud etc. That... and/or the glow battery might have already been a bit low by then. It didn't make a single "pop" during the second start-up attempt. I could have fished a glowplug out to see if the battery still had enough life left in it, but light and my enthusiasm were by then pretty much faded.

I'll still persevere with trying a few different things with this 'mechano' exhaust system. It may not be pretty. It may turn out to be not all that functional. But it was a lot of fun trying to construct something without having to figure out how to make a neat, tight circle out of 1" copper tubing.

And like I said before - I'm not an engineers bootlace. But that wont stop me from trying new things...

BJ

BJ64

@Tele...wondering if I should stick with the original twin 'squashed pipe' outlet idea (like the single bottom-end Keleo)...or you reckon maybe run a solid 1" diam pipe out both sides instead...?

Either way... I would still need to run some kind of lowest-point 'breather' to allow the over-run exhaust lube to drain out of, yah?

BJ

Carosel43

Believe me, I frequently suffer from a loss of enthusiasm so no worries.

SrTelemaster150

Since you are utilizing "lego" construction, why not try both? Use 1" on the sides & squish it down to an elongated oval W/ a small outlet on the bottom for drainage..

Kmot

My Feedback: (24)

I think your Pentagon shape is not only unique but rather interesting too.

tim750r

Here's a guy 'playing' with the exhaust note on his Moki 400

Interesting how the note gets more throaty with the long fat pipes...

http://www.youtube.com/watch?v=vPq1Aa715Jk

BJ64

Bloody Moki 400

That's cheatin! (and the sound I'd love to get )

BJ

vasek

My Feedback: (4)

Hey, I have a NIB AR 160 twin and when turned by hand (no plugs), there's a noticeable click sound in the crank at TDC or the max bottom travel of one cyl (hard to tell since they move in opposite direction). Should I be concerned ? I imagine the basic build is similar to AR400.

Thanks,V.
BTW is there a good thread related to the twin ?

EQ1

Hi Vasek,

although offtopic: I have two of them and they do not have this behavior. On the other hand, my ASP 120 does sound awful when turning it, but runs OK. Same for my Evo 9-99, makes this "click" sound on everey so turn, but runs OK so far. Looks to me that there is more play in the gears than should be. In German we say (concerning valve clearance): Wo Luft ist, ist auch Leben (Where space is, there is life)!

SrTelemaster150

The ASP 160T is a boxer twin & both cylinders are @ TDC or BDC @ the same time.

If you are running castor lube that clicking noise could be the exhaust valve popping off the sticky seat.