Supercharged nitro engine
 

Yes, I know bolt-on superchargers for nitro engines don't work, at least not well enough to justify the extra complexity. I'm just pondering something.

Nitro engines are designed so the exhaust port opens before the transfer ports do, to release exhaust pressure so exhaust doesn't blow down through the transfer ports and block inflow of fresh air and fuel. The side-effect of this is the exhaust port also closes after the transfer ports do, reducing the engine's compression, even with a tuned pipe on the exhaust to "bounce" the escaping fuel and air back into the cylinder before the ascending piston seals off the exhaust port.

But what if you engineered a nitro engine specifically to work as well as possible with a supercharger? If the crankcase were sufficiently pressurized by a supercharger, you wouldn't have to worry as much about exhaust blowing down through the transfer ports, so you could have an exhaust port that opens at the same time as the transfer ports, or even opens *later* than the transfer ports. (the exhaust port could be made wider to compensate for not being as tall, so it would still have the same flow-rate.) That would mean the transfer ports could stay open after the exhaust port closes, and the intake valve on the crankshaft could be adjusted to stay open for longer while the transfer ports are open, which would allow the supercharger to actually pressurize the combustion chamber properly.

Thoughts?

OS had one for a while.

Interesting. That's a four-stroke, though. I was thinking of a two-stroke valveless engine.

Also, it seems that my posts in Nitro On-Road Engine Zone don't show up in the search results when I search the forum for posts I've made.

If possible you should inject compressed mixture on the moment when the exhaust closes. A small oneway port directly connected to the turbo with an own (2nd) carburator just above the exhaust should make that possible.

Thinking about it, a few years ago there was a devellopment of (real) car engines using 2-stroke and 4-stroke technology...... so yes, my idea of small ports can also be translated to valves although high revs can cause floating valves and enough valve spring pressure will give a lot of resistance so it must be a rotating valve or an injector.

u guys are confusing a turbo and supercharger the os picture is a turbo, this is a supercharger and it works great!!https://cimg8.ibsrv.net/gimg/www.rct...bdb81047a3.jpg

Supercharger, Turbo or G-loader... they are power driven in different ways but all have the same goal, to power the air pump on the air intake.

OS used roots blower, they were not exhaust driven like a turbo, two completely different animals.

yes same goal but completely different ways of delivering that air u cant even compare turbos are so much more complex and what is needed to drive them ,,,,

I don't know what os has I was just referring to the os pic an that its a turbo setup..

No, that is not a turbo, that is a roots blower. To the best of my knowledge no one has ever tried to use a turbo on a engine of this size.
Just Google "OS Supercharged" and you will see pictures of it dismantled, here it is on the OS web-page, though not dismantled.
https://www.osengines.com/history.html

yes I just seen the video!! lol sounds really cool!! yes u really would not be able to do a turbo just the fact u need it to be oil cooled would be one of the many problems,,

The RB Innovations supercharger does not work. It will not create any boost of any kind. It will wiggle your whiskers at best though.

I have no idea if it works or not I was just stating that its a supercharger not a turbo....

Your post that I quoted has you saying it works great and I can tell you it does NOT work. I’ll also tell you there are two different kinds of superchargers. Roots type and centrifugal. The latter look similar to turbochargers.

There was a guy on RCU that was going to attempt to adapt a keychain turbocharger to a Nitro engine. I suspect it won’t work though.

I was joking when I said it works great...I would never have a need for one I only race onroad nitro I don't have any other nitro cars that I play around with …..

I always had the idea to try a kind of propellor in the bore of the crankshaft I even made a tool for it to make the blades but in a 1st atempt my machine was not solid enough....

The RB innovations does work but not as a turbo but as a mixture pump, videos shows a much better acceleration.

Those online videos show you what they want you to see. There is nothing scientific about them, so if you believe they work based on those videos alone - well.....

It would require a rubber seal with a spring around it to keep the seal clamped against the crankshaft as the seal wears-down, but that's hardly impossible. Every automobile engine already has seals like that. Also, a vacuum chamber ahead of the front bearing could be added, with a hose connecting it to the intake side of the supercharger, to recapture oil leaking past the front bearing.

If your test engines couldn't rev-up enough to reach the minimum RPM of your tuned pipes, then you needed pipes tuned lower. The power increase from turbocharging and supercharging is most evident in the mid-RPM range, so the vehicle could be geared higher and wouldn't require an engine (or pipe) that revs to the moon to generate power. It would be roughly equivalent to adapting a touring car to run on a truck engine nowadays.

Would all that work be worth the added complexity? Probably not, I mean you can always just install the aforementioned truck engine to get the same effect. But as a pure engineering exercise I think it could be made to work, if the will existed to do so.

Anyway, I have to say I'm surprised this thread keeps popping up.

Hence why OS went 4 stroke route, made it easier. I know I posted up a pic earlier of the FS-120S but here is some more to stoke the fire.https://cimg8.ibsrv.net/gimg/www.rct...0a3c8e4c89.jpg
https://cimg9.ibsrv.net/gimg/www.rct...0245ec5420.jpg


And here is a review:

OS FS-120 Surpass SP

That looks super cool. It's hard for me to gauge the size of the assembly in those photos; I see from a schematic that the engine mount holes are 58mm apart left-to-right, so I'm guessing the supercharger isn't more than 55mm wide, but I can't be sure.

Doing it over the summer when you're not busy with school sounds like a great idea. Let me tell you what will happen if you decide to wait until you're finished with school: Assuming your education has anything to do with your natural interests, it's entirely likely you'll never work on personal projects in that field ever again. I haven't written code for personal use in over a decade; I get all my code-writing kicks actually doing work nowadays, and I turn screwdrivers for fun instead.

In the meantime, you'll want to find some way to measure airflow so you can see how much air the engine pulls-in when it's naturally-aspirated, so you have some idea how much air your supercharger setup needs to be able to move. As a guideline, your supercharger setup will need to be able to pump 150% as much air as the engine intakes naturally, to generate 7.5psi/0.5bar/0.5atm of positive pressure inside the engine; if it can't pump that much additional air into the engine, the engine will probably experience a net power loss from driving the supercharger. You'll also need to move the carburetor upstream of the supercharger to avoid the additional complexity of needing a pressurized box surrounding the carburetor and a fuel tank capable of retaining the same additional pressure without leaking everywhere.

Unless you happen to have all the right equipment sitting in your garage, you're looking at months of occasional work to make this prototype. Best to start on the easy bits now.

Do you know how to google?
I know that is an unwanted reaction but with the hint you easilly could find pics...

VIR-TUS.21 Onroad - NOVAROSSI WORLD

Did you know that Novarossi patented the offset carb? This provides little detail but if you search for the patent in the EU, you can read the full patent: https://patents.google.com/patent/CZ...i&oq=novarossi

Don't know if this link will work: https://worldwide.espacenet.com/publ...=&locale=en_EP

Saw your original post. My point was that Edward invented this almost 20 years ago and Novarossi ripped it off. Maybe they didn't know, it's just interesting that they successfully filed a patent for something that was already on the market. Edward doesn't know who I am but I met him and his son at the Winternats around 2001/2002 and knew that everything he came up with was 100% original and new.

Novarossi was very busy to design engines different from standard like their weird bearings and indeed the offset carb. The offset carb is a solution to get the intake hole of the crankshaft in line with the crankpin which should give more balance in the crankshaft. We customers want to see improvements and so going outside the standard and giving it an interesting story will push people to buy the engine. And with patented designs no other can copy it with which you can make your own prices like the impossible bearing of the Virtus with a retail price of arround 115 dollar (!!!)

Look at their latest model:
MEPHISTO.21 ONROAD - NOVAROSSI WORLD

It is using the normal 14.5x26x6 bearing and a normal carburator.The cheaper OS, LM and Picco engines were getting more interesting for the market, not only with their prices but also performance wise which seems to me the reason to go back to normal designs with the result of lower prices du easier and more mass manufacturing and most of all with that, more satisfied customers.,

[QUOTE=Roelof;15416321 The offset carb is a solution to get the intake hole of the crankshaft in line with the crankpin which should give more balance in the crankshaft. [/QUOTE]

Not really. Wrong assumption. Offset carb was done to have better line up intake pass, balancing I can solve much easier.
Unfortunately I quite this beautiful hobby, I was in since 1975 till 2007. Now for 12 years I have different hobby.

Hm, I really do not know who you are. I guess we met at Winternats in 2004. My first show up, I came with PR12 engine, which had offset carb and sleeve with integrated intake ports and cooling fins, sort like it is done on real motorcycles 2 cycles engines. Next year I brought PS12 with Bi-metal sleeve, that year Tosolini was running my engine and he got second place. Than I joined Axial Racing and year later moved to different field.
Now my hobby is firearms. :D
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