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

[@rcdogmanduh4440]

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!

[@vumba1331]

Was the engine set up in a boxer configuration or did they run on the same bearing 9n the crankshaft, i.e. dounble throw versus single throw? If the latter it would've run only on the prime as there wouldn't have been any pulsing in the crankcase to operate the reed valve. Also they very very sensitive to the sealing on the front of the crank as that would also influence the gas tight seal. Well done on trying though, personally I was into the making of the RC gear from kitsets, that's how long I've been modelling!

[@davelowets]

Yes, with a double cylinder crankcase induction engine like that, sharing the same crankcase volume, there wouldn't have been enough volume change, and no "suction" to pull in any charge air, and no pulse to push it up into the cylinder. If you had made ot so that both pistons went to TDC at the same time, then it would have worked.

[@vespass225]

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

[@NoneNone-gk9wt]

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

[@K3Flyguy]

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!

[@guntherpommer6433]

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

[@davelowets]

A 5 Cox radial? Now THAT is the Shiznit! 👌😍 Very cool!

[@Del350K4]

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.

[@donchristianson3153]

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

[@ryancadwallader2049]

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

[@christiansprojects-cgmanuf1426]

Thanks!

[@CSHUNT83]

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

[@christiansprojects-cgmanuf1426]

Thanks man!

[@cliffcorbitt9494]

AN ABSOLUTE MASTERPIECE!

[@tanzanos]

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.

[@davelowets]

I bet you didn't.... It will NOT run unless you also built a supercharger along with it to get some airflow moving.

[@TestECull]

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!

[@tom5051666]

the engines you speak of have an exhaust valve in the head so it can stop the charger blowing unburnt gases out of the exhaust, like is happening in this video

[@TestECull]

@@tom5051666 Ye the supercharger would be wasting a tremendous amount of fuel/air charge in this engine, but it's also the only way a common-crankcase single row radial two stroke could function.

[@chrishenniker5944]

I want to see this one on a four stroke engine, where it’s supposed to be and where it would work.

[@davelowets]

​@@tom5051666These engines have sub piston induction. They will BENEFIT from supercharging. The exhaust port isn't connected to an intake transfer port like a typical 2 stroke is.

[@davelowets]

​@@tom5051666These Cox engines use sub-piston induction. There is no exhaust port connected to an intake transfer port like a conventional 2-stroke engine has. It WILL benefit from a supercharger.

[@scottobrien3484]

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

[@serpentcobra1717]

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

[@sailr]

Brilliant. I am anxious to see it on an airplane!

[@yashilghazi5948]

Beautiful craftsmanship!. Well done Sir.

[@gibbyrockerhunter]

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

[@christiansprojects-cgmanuf1426]

Thanks man!

[@mylesjarvis7571]

Incredible workmanship! Love it!

[@christiansprojects-cgmanuf1426]

Thanks man!

[@marcnissen578]

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

[@christiansprojects-cgmanuf1426]

Thanks!

[@jmt2727]

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

[@christiansprojects-cgmanuf1426]

That would be awesome.

[@antoniodellaragione6091]

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

[@brianbarnabee2317]

What a sweet build. Fantastic.

[@user-rs8zg8ey2b]

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

[@kennethconnors5316]

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

[@pierangeloquaglieri4860]

Complimenti, very beautiful work

[@skyshipam]

Awesome! I envy your talent and skill!

[@qownson4410]

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!

[@joseisraelramirez9251]

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

[@palacita135]

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

[@modelmakerz0690]

Beautiful work and video. Well, done!

[@yodasbff3395]

Beautiful workmanship 👍.

[@pedalcarguy]

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

[@christiansprojects-cgmanuf1426]

Thanks for the sub!

[@craigywaigy4703]

Nice! Always loved the Cox engines!

[@aileronmodelismo]

Awesome job!!! Impressive result.👏👏👏

[@faras5426]

Beautiful work!

[@miketee2444]

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.

[@Jimmyzb36]

Art in motion! Well done.

[@bac1995]

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

[@HenryL161947]

truly amazing , congrats and thanks for the video

[@parqld]

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

[@NicosProjects]

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

[@christiansprojects-cgmanuf1426]

Danke! Die PeeWees sind lustig. Die kleinen Wurfgleiter von Multiplex gehen ganz gut damit ;)

[@harrybobb6927]

@@christiansprojects-cgmanuf1426 hi I want to know if you can make me one like this is pay u to make me one

[@aSpyIntheHaus]

Marvellous work there! Great video too.

[@interman7715]

Fantastic engineering!

[@johntenhave1]

Wonderful effort! Very impressive.

[@donlawrence1428]

Very nice work. You are very talented

[@christiansprojects-cgmanuf1426]

Thank you!

[@reginaldluycx6700]

Fantastic work and no cnc used !

[@АлексейМышевский]

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

[@christiansprojects-cgmanuf1426]

Thank you!

[@davidcameron8819]

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

[@didierneeferc]

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

[@ahmedalmuhana6686]

Où puis-je trouver ce design mon ami .. si possible répondre

[@dangamsby6612]

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.

[@juliocesarmonsalvo7442]

Excellent project,

[@thehanger3436]

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

[@jdsstegman]

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

[@tonywright8294]

Superb looking engine A+

[@JB-br4zs]

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

[@user-rs8zg8ey2b]

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

[@homienat3374]

Nice job mate well impressed 🤙🤙

[@craigcoghlan546]

Lovely work mate, can I suggest a flat 4 next

[@christiansprojects-cgmanuf1426]

Thanks! Why not... I have a few other projects now but a flat 4 is a good idea as it will be lighter.

[@zoegnappe]

beautiful project!!

[@Africatwin93]

Einfach nur klasse!

[@avitekw]

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

[@Surestick88]

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?

[@christiansprojects-cgmanuf1426]

Correct. It wouldn't run at all without any pump.

[@michaelmcfeely6588]

Thank you for asking. I was going to ask this.

[@fromgermany271]

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

[@Lozzie74]

Nein!

[@randyleazenby2351]

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

[@christiansprojects-cgmanuf1426]

My plan is to buy a cnc-mill by next summer and then, we will see ;)

[@rigididiot]

@@christiansprojects-cgmanuf1426 If that ever happens, I would be willing to run glow fuel again (gasoline only nowadays) and definitely buy one.

[@GoingtoHecq]

obviously this is amazing.

[@alexgoldstein7553]

Wow fantastic!

[@TestECull]

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.

[@michaelrehmus]

The taps are available but I paid $60 about 6 years ago.

[@outlawflyer7868]

Now that's very cool...

[@josealfredoespanolyapor3751]

Impresionante,felicidades,muy habil.

[@christiansprojects-cgmanuf1426]

Thanks!

[@OkiThumper]

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!

[@chrisbirtle2124]

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?

[@jtuttle11]

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

[@stardust6066]

Totally awesome mate 💪👍😄

[@doglegjake6788]

Excellent video

[@rigididiot]

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

[@rockcrawler3119]

For the right price ANYTHING is for sale....

[@rigididiot]

@@rockcrawler3119 I bet it is... but what is the right price... :p

[@rockcrawler3119]

Depends how bad you want it haha.

[@rigididiot]

@@rockcrawler3119 True...Or how badly he wants to keep it :D

[@bojangle3712]

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.

[@rondaniels9974]

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?

[@halseyknox]

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?

[@christiansprojects-cgmanuf1426]

Yes, typical nitro RC-pre-mix with plenty of oil and some nitromethane to help cool the engine.

[@renaissanceman5847]

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 ...

[@rigididiot]

Yes you can, it is done all the time, and up to 3 bar boost pressure even. Not in this small size though...

[@renaissanceman5847]

@@rigididiot you cannot boost a 2 stroke from the inlet side... when the crankcase transfer ports open up to the combustion chamber, the exhaust port has already opened letting the burned mix out. when the piston is at bottom dead center... both the exhaust port and the transfer ports are open, while the inlet port from the carb is closed. when the piston is moving back up the transfer ports close first... then the exhaust port last. this is why we use tuned exhaust pipes. they provide a back pressure pulse of some of the air fuel mix that escapes out the exhaust port (pushing it back into the combustion chamber) just before the exhaust port closes, effectively adding more fuel air to the combustion chamber under pressure. look it up yourself as to why you cannot effectively turbo/supercharge a 2 stroke.

[@rigididiot]

@@renaissanceman5847 Aehm... I am a marine engineer, and having worked for decades with turbocharged 2-strokes (and with a degree in engineering) I seriously beg to differ... Google "turbocharged two stroke". The turbocharger acts not only as a charging device, but also as a backpressure device, resulting in some serious boost pressure (personally I have worked with up to 3 bar boostpressure).

[@renaissanceman5847]

@@rigididiot show me the link...

[@rigididiot]

You could google it for yourself, way more convincing, but if you insist: www.snowmobile.com/trails/polaris-working-on-turbocharged-2-stroke-snowmobile-engine-65385 www.snowmobile.com/blog/wp-content/uploads/2020/06/Polaris-two-stroke-turbo-patent-US20200182139.pdf www.ski-doo.com/2021-whats-new-ski-doo.html But you could also google for "MAN B&W two stroke" or "Sulzer two stroke"

[@davethrussell6794]

beautiful.

[@modellboerse]

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

[@Jimbo-in-Thailand]

+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!

[@christiansprojects-cgmanuf1426]

Thanks for your comment! That's a great Idea. I think these cylinders are still available from coxengines.ca

[@bannisterengines]

Very nice job thanks for sharing

[@sunfishensunfishen2271]

I would like to build a 5 cylinder twostroke radial to serve as a bicycle wheel motor. Are there other options for building the crankcase pressure such as using an impeller?

[@eskayler66]

Very nice!

[@iandaly8786]

Christian where is your flying video please? How did you calculate what propeller it would spin?

[@crankhandle]

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

[@christiansprojects-cgmanuf1426]

Thanks. Surprisingly not. It runs much smoother than a comparable single cylinde engine. It's quite heavy which helps and it seems that I got the crankshaft counterweight just about right.

[@terrygoyan]

Are those TeeDee 0.049 pistons and cylinders? The cylinders we used did not have the webbing across the exhaust ports. That may limit the scavenging...... Beautiful job! Now a tuned pipe on each cylinder, would be amazing. What size prop were you spinning?

[@christiansprojects-cgmanuf1426]

Hi. These are regular BabyBee cylinders. Maybe I'll upgrade to TeeDees one day. The Prop is a 12x5.

[@terrygoyan]

We used to work on TeeDee’s to get maximum rpm out of them. The connection of the connecting rod to the piston often had some slop. There’s a tool that we used to tighten the ball joint to remove the play. There was some variation on the intake milling and going through multiple cylinders could make as much as a thousand rpm. The best cylinders were milled to the point of almost cutting into the mounting threads. Dropping the glow plugs slightly into the cylinders also could improve the output. I love your project. I’m sure you could get significant improvements on power output with a little work. Thanks for bring back some old memories!

[@BensWorkshop]

Very nice.

[@kevintheblacksmith]

Amazing

[@peterg2yt]

Terrific and unusual project. I am hugely impressed. As a matter of interest, do you have any idea of how much power the compressor added, compared to the normally aspirated engine? I'm sure there is scope for improving the power, but there really wouldn't be any point served in doing that... objective achieved very well. Thanks for poting this video!

[@notanotherrcchannel]

As I understand it, the engine wouldn't run at all without a compressor! The 2-stroke design requires crankcase pressure to force the fuel/air mix through the transfer ports when the piston is descending. On a single cylinder, or boxer twin, the piston itself creates this pressure as it plunges into the crankcase. In the radial configuration, each piston is in a different phase of stroke; one going up while another goes down, etc. The relative volume of the crankcase stays pretty much constant, so you need forced airflow. Large 2-stroke diesel engines work this way as well.

[@peterg2yt]

@@notanotherrcchannel Hi Bryan, yes, when thinking about it you are obviously right. Thanks for pointing that out. Brain fade on my part!🥴

[@gamajulio1]

Great job 👏

[@derekinbritishcolumbia1449]

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?

[@christiansprojects-cgmanuf1426]

Hi. I have never measured rpms. I use a 30% nitro, 5% castor and 15% synthetic blend. If I get it to run more reliably, a Stearman woul definitly be an option.

[@jpia5784]

Did you get your new mill? I'm finishing my 3rd radial for a 100 yr old WW2 fighter pilot.

[@billfrederickfrederick2791]

Beautiful machine work and excellent outcome...but that music ...had to turn the speaker off !!!

[@homefront3162]

Those steel pistons should holdup well

[@adanmirapedrol8703]

really cool AMAZING

[@Canyonman44]

I don't suppose you would have a set of plans for sale? I would love to have a set! Excellent Job, BTW!

[@christiansprojects-cgmanuf1426]

I do have some plans but they are very rough as I never intended to sell them. There's only the main dimensions on them as I made many details on the fly. Also, they are in metric. Are you still interested?

[@Canyonman44]

@@christiansprojects-cgmanuf1426 Yes Please

[@LCMNUNES1962]

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