Supercharged Micro Radial Engine: Making of (New Project coming soon!) 

1974 I made a twin opposing cox .049 . I single pointed the crank case bores in a southbend lathe turning the chuck by hand. Used the reed valve the same as Cox but engine only ran on prime then quit. I was 16 years old in trade school. This was so much fun the watch!

I built a 5 cylinder cox radial and I also had to make my own die. This was back in 2000. I got over 12,000 rpm on a 9x4 prop.

This is soooo impressive...! The pinnacle of traditional engineering.

As much trouble as we had with em as a kid I would only hope 5 at once would not mean 5 times more trouble! Thanks for sharing, very nice video and excellent piece of work!

You go man your living my childhood dream. I always wanted a Cox radial. I thought that up in the late 70 s but never did it

heh. That thing runs pretty good. And a nice, simple, robust way of solving the issue of scavenging on a radial two stroke where there would be no natural pre-compression. Technically speaking the engine is naturally aspirated; it draws heavy parallels with the Detroit Diesel 2-stroke truck engines and EMD 2-stroke locomotive engines scattered across America, mostly in how they breathe. Like this engine, they lack natural pre-comp, so they use a supercharger to force feed the cylinders, and are considered N/A when there is no boost device feeding into that supercharger. Can't wait to see it fly!

2 stroke cox radial....simply awesome building skills...my respect!

Sei un ARTISTA , non ho mai visto una opera tanto PERFETTA e FUNZIONALE . I miei complimenti 🎉. Continua SEMPRE così 👍👍👍👍👍

My goodness - what an extraordinary piece of work! The precise drawings were an encouraging sign from the beginning. I was concerned that if the crankcase volume were too great, there could be a risk of the downward movement of a piston failing to boost crankcase pressure sufficiently to send a charge through the transfer ports, but I guess the compressor neatly obviates that potential problem.

Ich freue mich schon diesen Motor in Action zu sehen! Hut ab von dieser genialen Arbeit!

Excellent engineering and construction!!!!!! Ya should market this !!!! Believe me it would sell !!!!!

What a wonderful piece of engineering and such a creative idea!….brilliant!

Congratulations. I thought I was in for another " look what I drew and got the cnc to make me" very nicely done. I like the supercharger

Beautiful craftsmanship!. Well done Sir.

What a sweet build. Fantastic.

That is a work of Art. Amazing. Well done !👍

Awesome! I envy your talent and skill!

AN ABSOLUTE MASTERPIECE!

this is genius ,, you did something really cool AMAZING it seems to be a runner

Incredible workmanship! Love it!

Marvellous work there! Great video too.

Beautiful work and video. Well, done!

Thank you for completing my childhood dream!! Awesome work!

truly amazing , congrats and thanks for the video

Un grand bravo! votre travail et votre savoir-faire sont tous les deux fantastiques, extraordinaires! Encore bravo pour ce magnifique moteur en étoile! Thibault

Hey! I didn't realize someone was doing the same thing as I am. My friend and I are working on this exact same kind of project!

Nice! Always loved the Cox engines!

Awesome job!!! Impressive result.👏👏👏

very nice work... not easy to pull that off. all radial 2 strokes with a master rod need that air-fuel pump to work... technically not supercharged (you cannot supercharge/turbocharge a 2 stroke from the inlet side), but here the pump is required for transfer and scavenging to keep the crankcase at a positive pressure to the combustion chamber ...

Complimenti, very beautiful work

Beautiful workmanship 👍.

Give it a shot in air, will love to see it fly

Wonderful effort! Very impressive.

Art in motion! Well done.

Great work! Can't wait to see and hear a V12 version of this!

Beautiful work!

Fantastic engineering!

beautiful project!!

I love everything about this. Even down to that kick ass Swiss VictorI knife.

Einfach nur klasse!

Это превосходно! Не просто прямые руки - а золотые!!! Побольше бы таких интересных видео и материалов в интернете а не всякие там котики или глупые челленджи.... УСПЕХОВ тебе МАСТЕР

Marvelous work. I tought a radial engine 3 stoke was not possible. Due to the canceling effect of the pistons on the crankcase not contributing to scavenge the fuel properly

Superb looking engine A+

Sounds great. Those little cox motors were fairly agrivating as a kid. Maybe it was the kid part but the multiple cylinders sure seemed to smooth them out.

Totally awesome mate 💪👍😄

Really well done. i love the idea with the compressor. i have built the V2 20ccm from VTH verlag but it has problems running. maybe ill give it a try with the compressor as well

Excellent project,

Wow fantastic!

Thanks for sharing! ~25 years ago I was flying U-control 1/2A with 3 up combat with a super simple basically indestructible home brew planes with 049 black widow motors. My third black widow motor I got was a dud, would barely get 14K rpm, where my other two 049's was in the 18K rpm range with 10% nitro, thimble drone 5x3 prop. Troubleshooting the dud, a friend showed me how to lap sand the case at the carb/tank mount (1500 grit sandpaper put on glass and sprayed with wd40 and sanded in a figure 8 pattern), it knocks off the bulge of the 4 course carb/tank mounting screws (a black sharpie put on before the sanding will show the progress). This did not seem to help the dud motor,,,,but I got an idea. Why not try it on where the cylinder screws in (effectively changing the timing). I passed my idea by a buddy that road raced the two stroke Yamaha RD400 (and was a auto/diesel mechanic), he said I should raise the exhaust ports (so not remove material, but add to it), so I made a 0.010" base gasket, this made it a super dud motor, lol. To scientifically gauge what I was about to attempt I measured the height of where the cylinder screws in to the case (see picture of the red lines where I measured - from case to where cylinder screws in), I call this deck height, my normal two good motors was 78 thou (0.078"), the dud was 84 thou, instantly a big grin appeared. With the precision these cox motors are built to, wth was going on with this spec, 0.006" too tall. I started by taking 5 thou off (glass/sandpaper/wd40, same as I mentioned above) and retesting, result was better, another 5 thou, even better, another 5 thou and was getting hard to start. Then I thought why it was hard to start, hmmm, way to much compression, perfect, the head gaskets were 5 thou, I can compensate with head gaskets, so for every 5 thou I removed from the deck, I added 1 more head gasket. After continuing this process a few more times (I went down to 53 thou from 84), it turns out, 15 thou off the good motor (was 78 thou, now reduced to ~63 thou with 4 head gaskets (1 original +3)) was the best. Results are with 10% nitro, Thimble Drone 5x3 balanced prop and plastic reed valve. Bone stock good motor with 78 thou deck height = 17-18K rpm, Bone stock dud motor with 84 thou deck height = 14K rpm, Best was reducing to ~63 thou deck height (on all motors), with a total of 4 head gaskets, 25Krpm and one hit 26Krpm. A gain of 7K rpm! For pictures and discussion, google search coxengineforum black widow tuning

A work of art I should say a running work of art

Great job 👏

Nice job mate well impressed 🤙🤙

OK this is absolutely amazing!! really 👍👍 thumbs up 10 out of 10 Instead of the music I would actually just rather hear you talking about the machining process maybe some of the parts that gave you some trouble or things that you may be had to do twice because you made a mistake but really absolutely astonishing great craftsmanship and I’m glad there are still machinist in the world

Good that the shape of the compressor rotor is hidden behind an aluminum case. 😂

Brilliant!

Excellent video

Die guten alten Cox-Motoren! Hab auch noch 2 PeeWee zu Hause. Tolles Projekt!

Very nice!

Awesome! A 4cc five cylinder radial engine! Instant subscribe!

Now that's very cool...

put this beauty on an plane!!! its awesome!!!

Cool I saw a 5 cylinder home made cox radial bring $1,800 on ebay about 2 or 3 years ago.

beautiful.

Very nice work. You are very talented

really cool AMAZING

Impresionante,felicidades,muy habil.

Fantastic work and no cnc used !

very cool build. I would try and use dave sullivan heads and better glow plugs and you may get the reliability that you seek. I remember using them with throttle rings on mine .....and I could slow em down to make the sound of an electric fan!!!!!! then open er up and let the black widow scream.

obviously this is amazing.

I like it!

Amazing

Very nice.

AWESOME!!!!!!

Awesome!

Very nice job thanks for sharing

Well done!

I would definitely buy one. The look of it is so cool

I've got a few of these little motors laying around including ones that were 'Factory built throttalble'

you deserve more views

Good job, like 7

+1 Christian - Excellent project and had to leave a 667th like as _666_ likes has scary connotations. Haha! A suggestion is to try to find some earlier 1960s era Cox cylinders that don't have the horribly restrictive exhaust ports. The previous version had 2 large slots (one on either side) and were much more powerful than the anemic ones you have. I'm sure they would provide quite a power boost to your little radial. The trade-off would be they're much louder, which is probably why Cox revised that design way back when. Merry Christmas from Thailand!

No way. Just came across my feed. Im half done with the same build. Never thought about supercharged tho....

Ventom cylinders/pistons and high compression heads are the way to go.

EXCELENTE SERVIÇO 👍👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻👏🏻 🇧🇷

Lovely work mate, can I suggest a flat 4 next

Absolutely brilliant chap, Well Done. You need silencers or the people would complain, its like a symphony to me but others would moan! Is it all en 8 did you have to use any v155 on it?

Just curious, but have you made any further progress in putting this engine to use in an aircraft. I found your video posted on Cox Engine Forums dated Dec. 28, 2020. If you have, we'd all be interesting in hearing about your endeavors. Thanks for sharing!

What an absolute BRILLIANT piece of engineering... If it were for sale, I'd buy it... (but I know it's not for sale... :( )

Very cool, amazing, nice. BUT...what is the power to weight ratio? Looks heavy. Looks like it would fit another cylinder. And yes, I'm a critic who would be hard pressed to build an engine that cool.

Did you consider using the master rod assembly as half of a scroll compressor?

I think there would be a moderate market for such items. Especially for upgrading Guillow and dumas kits. Give it a shot!

That is friggin cool....even the making of a tap was impressive in its own right....just curious what keeps the main bearing oiled, pre-mix like typical two stroke?

Very cool project! I'm curious as to why all of your connecting rods float in the main con-rod carrier. Doesn't one con rod usually serve as a master con-rod to control the rotation of the con-rod carrier?

Nice work, excellent result! Do you supply the project?

5:50 "ein Schelm, wer Böses denkt" :-)

Impressive build. What performance are you getting? What fuel blend are you using? Would like to see the model you fit this to. Perhaps, a WWI Sopwith Camel, Waco or Stearman?

Amazing work! Is sounds very smooth? Its there much vibration?

Beautiful and impressive without any CNC! Congratulations. One question: how you made the master connecting rod not rotating with respect to the spider plates? Thanks and cheers from Tuscany

1:05 I live in the not-metric part of the world and I wouldn't be able to find one either. Leroy Cox used a really bloody oddball threadform for those cylinders.

I'm guessing the forced induction was necessary as there's no pumping from the pistons going up and down with the cylinders firing one after the other like that giving you a constant crankcase volume?