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-   Onroad Nitro Engine Zone (https://www.rctech.net/forum/onroad-nitro-engine-zone-71/)
-   -   Supercharged nitro engine (https://www.rctech.net/forum/onroad-nitro-engine-zone/971294-supercharged-nitro-engine.html)

Roelof 07-04-2018 05:37 AM

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.

RCTecher12 07-04-2018 06:00 AM

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.....

EdwardN 09-22-2018 11:39 PM


Originally Posted by fyrstormer (Post 14770494)
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?

There is something you have to take to consideration-sealing front bearing with ZERO oil leak would be unsolvable task. It will leeak like hell. As far as performance, we tried to do it in 1987 and 1988 with no positive results. We did it on runing in stand, turbine impeller was mounted directly on cranck shaff. We made shit load of different turbines, some of them was loading engine so badly, it couldn’t wind up to tuned pipe.
Many people around the world have tried and no one got any positive results, as far as I know.

fyrstormer 09-23-2018 06:49 AM

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.

fyrstormer 09-23-2018 10:09 AM

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

EdwardN 09-23-2018 08:18 PM


Originally Posted by fyrstormer (Post 15304560)
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.


You have valid point.

So little we know about those engines.
Are you talking from real knolowladge and expirience, or just use logics?
BTW, for the record, offset carburetor I made 10 years before Novarossi did. This is very well known fact here. https://www.rctech.net/forum/onroad-...-tus-21-a.html page 7

1/8 IC Fan 09-27-2018 08:44 AM

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

Broloff28 03-17-2019 06:00 PM


Originally Posted by fyrstormer (Post 15304639)
Anyway, I have to say I'm surprised this thread keeps popping up.

I just discovered this thread and it’s pretty entertaining to read. I’ve always wanted to attempt something like you were talking about. I even went as far as to buy a keychain turbo (not a supercharger but close enough) but it was never going to make boost so I gave up. I think this summer when I’m not so busy with school I might try to draw something up in cad. If you designed it right you could 3d print a turbine and make a centrifugal supercharger. Maybe I’ll try that on my magnum xl-52 four stroke

fyrstormer 03-17-2019 08:33 PM


Originally Posted by EdwardN (Post 15304928)
You have valid point.

So little we know about those engines.
Are you talking from real knolowladge and expirience, or just use logics?

Partly experience and partly logic. I have owned turbocharged cars before, and I've done work on them to get more horsepower, which involved learning about the ways in which supercharged/turbocharged engines operate differently than naturally-aspirated engines. I extrapolated from that experience and tried to apply my knowledge to our little nitro engines.


Originally Posted by EdwardN (Post 15304928)
BTW, for the record, offset carburetor I made 10 years before Novarossi did. This is very well known fact here. https://www.rctech.net/forum/onroad-...-tus-21-a.html page 7

Do you have a picture? The link to the Novarossi website doesn't work anymore.

fyrstormer 03-17-2019 08:38 PM


Originally Posted by 1/8 IC Fan (Post 15307097)
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.

fyrstormer 03-17-2019 08:47 PM


Originally Posted by Broloff28 (Post 15415526)
I just discovered this thread and it’s pretty entertaining to read. I’ve always wanted to attempt something like you were talking about. I even went as far as to buy a keychain turbo (not a supercharger but close enough) but it was never going to make boost so I gave up. I think this summer when I’m not so busy with school I might try to draw something up in cad. If you designed it right you could 3d print a turbine and make a centrifugal supercharger. Maybe I’ll try that on my magnum xl-52 four stroke

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.

Roelof 03-18-2019 12:13 AM


Originally Posted by fyrstormer (Post 15415628)

Do you have a picture? The link to the Novarossi website doesn't work anymore.

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



jimiaxplyr 03-18-2019 09:10 AM


Originally Posted by EdwardN (Post 15304928)



You have valid point.

So little we know about those engines.
Are you talking from real knolowladge and expirience, or just use logics?
BTW, for the record, offset carburetor I made 10 years before Novarossi did. This is very well known fact here. https://www.rctech.net/forum/onroad-...-tus-21-a.html page 7

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


jimiaxplyr 03-18-2019 07:16 PM


Originally Posted by SlowLST2 (Post 15416147)
Nevermind.

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.

Roelof 03-19-2019 12:41 AM

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.,


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