Thanks- the 2-1 setup I saw - did not work well -and the theory on making it work well escapes me -
The dimensions on the setup shown on the BME page certainly looks good -but fitting that all into a cowl is a bit of a puzzle.
We try all sorts of tuned.non tuned devices and even some new in cowl stuff.
So far - nothing we have seen, that is TOTALLY in cowl -is both quiet AND capable of zero power loss. You get one or the other .
We have only seen DA/ZDZ and 3W on these tests -and frankly will be surprised to see one which does both.
The setup Al welded up - was a group of the KS curves which, when all welded together made 22" -into a can using the rear of the can as a reflector - much as the Chapman -or from the pics of the set up on the BME site - likely used on that prototype - it works and works well
the problem is that it simply can't be hung onto an engine -like the current crop of "in cowl" devices - (mufflers)
simply too much stuff to hang --and some kind of a vibration isolator and additional support is required.
The Zenoah mufflers -(lawn mower look alikes) are not all that bad -
and better than some "model types " which are just a tube on a box.
A "rat maze" in a box seems to have real possibilities -as the maze can be constructed to make a long path , in a confined area.
The hook in all of this is that an in cowl tuned muffler , which works great on one timing setup ( exhaust dwell) falls flat on it's asp using a different port setup.
The difference can be pretty high.
Anyway - I hope this setup BME is trying - is a success .
We are setting up a rather different "in cowl" muffler which is an attempt to keep it all in the cowl - One thing we are stuck with tho - It just can't hang on the two exhaust bolts .
the engine vibes will simply kill it in a short time .
The best so far looks like the "muffler " will be as large as the engine .
And that's about as small as it can be - to get better -it gets larger.
Any thing that beats this size problem wil surely be a winner .