Po'boy's exhaust throttle for thin wall cylinder

David, I can see that it's pretty COLD where you are.

I see your hand shaking.. while holding-tight to that little engine. There seems to be a lot more throttle-resolution now. Have you thought about making bench-mounts for running your model engines? I enjoy making engine-mounts and test-fixtures.

balogh wrote:Great result Roddie  (cookies included   ). Too bad there are no milled flats on the top fin for the wrench. Like on my old stock 051 cylinder. These cylinders tend to bake into the crankcase and removing them without the wrench is not easy. I have never managed to remove a cylinder with the leather strap no matter if I preheated the aluminum crankcase..not that it needs to be removed so often. But the exhaust throttle will not make it easier either.

Will you bench test it? One of the claim points in the Proportional Exhaust Throttle patent by the inventor Mr. Roger Freiheit was the bimetallic throttle and cylinder combo, that will allow more blow-by thru the throttle when the engine runs hot and the brass throttle expands more than the steel cylinder, and better fit for throttling when idling with the engine temperature dropping lower...so fitting it tight when cold is just good the way you did it Roddie..

Hi Andras! Yes.. the cookies I make a double-batch of the Nestle original Toll House cookie recipe (it's written on the package) except I also add a 10 oz. bag of Reese's peanut butter chips. One pound of salted butter sticks.. softened in the microwave.. 4 eggs.. 3 cups of sugar (half light-brown) pure vanilla extract X2 tsp. 4 1/2 cups of all-purpose flour.. some baking soda.. some salt.. and a Kitchen-Aid Mix-Master.. to do the tough job. I used to mix by hand before Lynne bought me the machine.. and I used to make cookies maybe once every 9-12 months. Now I make them every week..   just kidding.. but I've made them twice in the last few months.

Regarding the exhaust-throttle..  I never thought about the cylinder-removal.    I also have a few different strap-wrenches that I can try. I guess I've been lucky not to have any Cox  cylinders that were stuck-tight in a crankcase.

I'd hoped to run an engine, with my "brass-band" po-boy exhaust-throttle tonight.. but I got distracted by another model-engine accessory that needed maintenance; a bench-mount for twin Cox .049 product-engines that I'd made; having a single-tank/dual-feed arrangement for running two engines simultaneously. It "did" work.. and I posted a hideous video a while back; running a pair of DAL brand 5"d. X 4"p. 2-blade drone-propellers "right-hand" and "left-hand" rotation. Those engines were tested for.. and are now mounted on my P-38 Lightning.

I think that the po' boy exhaust throttle idea has merit Andras. We will make it so.   You may remember my A Cheap Sport Muffler thread.. We may be able to incorporate an effective exhaust-throttle with noise-reduction.. with a little experimentation..  

Last night I found the twin-engine bench-mount while dragging-out my power-panel. The twin-mount utilizes a plastic (translucent) 35mm film-canister having dual (gravity) feed-lines and is mounted on top of a small "T"-shaped fixture. The canister (tank...) was mounted with a single small wood-screw through the bottom.. with something I'd used for a gasket. Well.. upon inspection, the gasket material had deteriorated.. and needed replacement. I used some thin butyl-rubber to make a new gasket.




The cap of the film canister has a small hole drilled in it for a vent.



I know it's show & tell.. but it's all I've got for tonight..

That is a very neat installation! Using a circlip as a spring is a good idea, and using the gap of the circlip and the tabs on the aluminum as a non-slip is genious. Congrats