Re: the Fatal Flaw engine

I tried to make a connecting rod but not perfect lets say i Will do bether wit the second one I will continue to work on this piece To repair the hole that I missed I could use a brass bushing The first time it's never perfect

I knew it wouldn't be easy that's why I wanted it The higher the difficulty level, the better But I immediately wanted to have it because this engine model is different, that intrigued me It’s Not all the same parts its weird that with the .15 models, there is a difference between the parts of al the different models. Larger cylinder larger piston i dont understand that the rc aluminium exaust model is Not the same size as the rc ring ?? And the précision throttle control fit m'y sportsman .15 cylinder Who are too small tread To fit this rc médalion

David long shot but check out and see if still for sale

https://www.rcgroups.com/forums/showthread.php?4014611-Cox-Medallion-15-Runner%21-Complete


ooops it sold already....sorry

It is this piston model that I want to reproduce as closely as possible to the original that I can Also add some modification improvement to the original design
It is this model of piston which should be found in this engine

Due to the extremely cold temperature I was unable to work in the garage Here is the temperature indicated on my little duratrax thermometer -54°c The fingers would stick on the handles of the lathe

David, you may want to bid this one:

https://www.ebay.com/itm/2203-Cox-15-Medallion-Model-Airplane-Engine-Cylinder-Piston-15-AlsoTee-Dee-/224785953877?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=711-127632-2357-0

strange its Not there Not avalible ? Looks like he's already gone? I don't know it's strange no sale price

davidll1984 wrote: strange its Not there Not avalible ? Looks like he's already gone? I don't know it's strange no sale price

That's Bernie's alternative eBay store so it might pay to contact him and ask why it was withdrawn.

I sent a message but I don't know if it is still available  I would only use the piston I would like to find a piston alone no nead of a new cylinder m'y is new I was working on à conecting rod To day
But if I can find the right piston I prefer to install the right part than to do wit what I can find that fit i found a enya .15 piston that fit Somehow in the cylinder but I would have to modify it a lot to be able to use it which is out of the question in the worst case I modify all the engine to use piston made of aluminum I am thinking of inserting a new sleeve I have measured it is possible and feasible but this cylinder is new and if i do this I'll swap it for an old broken rc .15 cylinder If anyone has an old broken and defective cylinder for a rc .15 mabe i have a new rc cylinder To trade  It's hard and almost impossible to find just a piston This is the kind of piece that we find in pairs That if I buy a replacement the cylinder will surely come with its piston so I think for now I'm going to put this engine aside and wait and see

davidll1984 wrote: I think for now I'm going to put this engine aside and wait and see

I think that's best. By rushing you may end up wasting a lot of time and possibly damaging irreplaceable parts. It may take some time, but I'm sure that if you are patient then you will eventually find the correct piston and rod.

Posible one day mabe It's not like I don't have another engine to play with I got this engine at a good price, it's not that bad I found another new one that seems to be still available It’s sure that I’m not going to wait for years otherwise that's what I'm going to do my best to give her life no matter what hapen To it its just for the fun

Well here we go again my brain hasn't stopped working on the problem of this engine with different pistons but a predominant idea that doesn't stop To come back I put it aside then come back as an obvious sign That I'm going to have trouble finding such a rare piece and that this cylinder must remain as it is So I decided to tempt to make a cylinder liner made of aluminum to insert inside a cylinder made of chrome plated brass from another engine which has nothing to do with Cox engines by the way It was while talking about these engines that the idea came But seemed wacky to me ... but I imagined it differently, in other words it was just a start The spark that started it all in m'y brain I also found some special points of this engine that I had never seen in this way a small simple modification
That I had never noticed on other smaller motors On the crankshaft a small notch which leads to the cavity this smaller part of the front the place for oil To lubricate crankchaft I wonder if another different medallion model has this little detail.???

I said to myself well that's what I needed to fill this cavity with pure Castor oil on the first start. I have this habit that came to me a long time ago I used to put a few drops of pure oil in the venturi then with the finger I blocked the air inlet I turned in the opposite direction several times then the excess I brought out and emptied it directly into the fuel bottle we can see that less oil comes out
Ok back to the main idea the idea is to build a new upgrade for these .15 I believe this could work well But I face several challenges the first is to make the treads of the base of the cylinder But nothing is impossible at this point I recovered some materials for the manufacture of this project  
      I also have another project in the shadows to hide from view an engine which will be very special I don't think anyone has seen this prototype engine at least not with this configuration of parts

today the temperature allowed me to work in my garage I made some modifications To a .15 ae engine
She's made very thin now

I even made a little video next the cylinder It will end in several video step by step

Here is the cylinder in production

It will be bigger but lighter in the end

Today I have a good day to work on the new cylinder the temperature is warmer my garage is very poorly insulated only a smal section for the machine room is insulated I was able to drill the hole in the center and enlarge it with a boring bar its Not finish and it would already be over if I could receive the die faster i have received the handle die holder

During this time the piece is stuck in the chuk to keep the geometry and Not of set the hole or the tread i have To made Perfect first time It's a long wait .

Finaly in time
We're going back to work, let's go, I'll make another video soon

Good progres To day

Let's say that I'm almost finished but there are still some details to be worked out I can't wait to test to see the result As I anticipated the engine should be lighter It's not finished but already lighter than the original Remaining holes to be drilled And the depth of cooling fins

I'm almost done in this form the motor could run but I want To instal a tune pipe so y have To make a exaust collector I also have to find a shim for the Front trust washer Cause if I push on Back and forth it move its not good for the connecting rod Because it's not loose enough and has no ball joint at the end
Like the original cox engine has so far everything should be fine once finished I can't wait to test it

I see you have ported the cylinder , do you have a fit that the liner want rotate ?Looking good !

Yes the liner cant rotate Its lock in place with the screw of the motor head plus it is very tight To inserts Not just wit hand I am working on an exhaust system I would need a profille pipe I can use a car pipe for tests Another stage where I scratch my head Thinking what I can do to come up with a viable system that does something Several small modification not mentioned some Who would get too technical to explain The crankcase is original unmodified but everything else yes

some well planned, beautiful machinework there. outstanding!

À Litle update on this engine it work Ok ok no too hasty excitement I have to finish this just have the motor in one hand with the glow driver on the other But what I thought I don't know But let's say it's less worse than you might think As you can imagine it would be hard to do this without injury or damage. Let's say that a small injury on me is not serious On the other side the glow driver and the propeller Won't fix it on their own like me m'y thumb is ok Just a little burn cause I put my finger on the exaust hole i was trying to prevent the motor from gaining more rpm speed Never again is it too scary That's not all I had to stop it with the other hand which held the glow driver firmly. Who finally stopped the engine Here the result of my very not brilliant idea

But I'm very happy with the result anyway. It's not a small burn that will make me cry the prop on the other hand