Ian w Posted June 2, 2016 Share Posted June 2, 2016 If a two cylinder nitro engine (not a twin engine) is timed to run together ie: one is on the opposite stroke to the other, does that mean it is capable of twice the RPM of a single cylinder ?. Quote Link to comment Share on other sites More sharing options...
Rory Posted June 2, 2016 Share Posted June 2, 2016 I'm pretty sure the engine speed would stay the same, it's governed by friction, the increase would be in torque rather than rpm. Quote Link to comment Share on other sites More sharing options...
Daveyb84 Posted June 2, 2016 Share Posted June 2, 2016 yeah it wont effect the RPM, think of a normal car, rps stay the same regardless of no of cylinders, same with motorbikes etc. you would get more torque with it being a larger displacement engine 1 Quote Link to comment Share on other sites More sharing options...
Rory Posted June 2, 2016 Share Posted June 2, 2016 I think the Schumacher manic twin engines are joined are they not? A common crank ? Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 14 minutes ago, Rory said: I think the Schumacher manic twin engines are joined are they not? A common crank ? Not a common crank but are timed through a belt. If you strip the engine for service you need a special tool to time them up. It`s the manic that has prompted me to ask this question. When one piston is up the other is down. So my way of thinking is you are getting two power strocks in the same time as you would normaly get one ?? Quote Link to comment Share on other sites More sharing options...
atom3624 Posted June 2, 2016 Share Posted June 2, 2016 You're getting twice the number of power strokes from twice the number of cylinders. No change in RPM - all nitro are ~27-40k depending on tune, type, etc. Al. Quote Link to comment Share on other sites More sharing options...
Ziggy122 Posted June 2, 2016 Share Posted June 2, 2016 In 1 revolution of the crank you will get 2 power strokes = double the power (torque) Rpm will not be affected in the increased department, probably loweres due to double resistance from compression and double friction Itd be cool but probably not viable... in an rc Sent from my GT-I8190N using Tapatalk Quote Link to comment Share on other sites More sharing options...
Daveyb84 Posted June 2, 2016 Share Posted June 2, 2016 according to the manual, now dont quote me on this, im just going off what i see the engine looks like it strokes at the same time but i think the manic is 2seperate engines working together so you would expect this. on a vtwin motorbike say, the strokes would be 180 degrees out because its one engine with 2 cylinders Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 (edited) I have been running mine today and they definiatly stroke at different time ie: one piston is up the other is down. And you need a timing tool to time the engines. Timing tool is shown in your picture one piston is going up the other down. Edited June 2, 2016 by Ian w Quote Link to comment Share on other sites More sharing options...
Daveyb84 Posted June 2, 2016 Share Posted June 2, 2016 yeah i agree, going from this page, it looks like the crank is 180 degrees out. i didnt see this page haha. do you have a manic then? are they as rapid as they look in vids? Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 2 minutes ago, Daveyb84 said: yeah i agree, going from this page, it looks like the crank is 180 degrees out. i didnt see this page haha. do you have a manic then? are they as rapid as they look in vids? Yeah I managed to pick one up quite cheap from the bay a while ago. The biggest problen it has a fairly small fuel tank and it drinks a lot of fuel and the tyres expand at full revs. Quote Link to comment Share on other sites More sharing options...
Anthoop Posted June 2, 2016 Share Posted June 2, 2016 1 hour ago, Ian w said: Yeah I managed to pick one up quite cheap from the bay a while ago. The biggest problen it has a fairly small fuel tank and it drinks a lot of fuel and the tyres expand at full revs. What Rory said up there is correct...all you get is more torque...Schumacher missed a few tricks ( but also avoided problems) by combining the exhaust and carburettor....if each engine had a carb/exhaust then the total unit would be more powerful......but still under geared. Quote Link to comment Share on other sites More sharing options...
Anthoop Posted June 2, 2016 Share Posted June 2, 2016 Oh and there are ways to get the engines timed together without the need to buy suff but it is a bit involved... Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 1 minute ago, Anthoop said: What Rory said up there is correct...all you get is more torque...Schumacher missed a few tricks ( but also avoided problems) by combining the exhaust and carburettor....if each engine had a carb/exhaust then the total unit would be more powerful......but still under geared. Yeah but by doing that you are back to the problems of tunning each engine and hoping to get the same tune so you may as well stick to 2 totaly seperate engines and hope you are getting the same tune. The only mistake that Scumacher made was not having a shared crankshaft. After all a few years ago before fuel injection and multi choke carbs most 1/1 cars only had one carb and one exhaust. I would rather use a proper tool then hope to get timing right Quote Link to comment Share on other sites More sharing options...
Anthoop Posted June 2, 2016 Share Posted June 2, 2016 4 minutes ago, Ian w said: Yeah but by doing that you are back to the problems of tunning each engine and hoping to get the same tune so you may as well stick to 2 totaly seperate engines and hope you are getting the same tune. The only mistake that Scumacher made was not having a shared crankshaft. After all a few years ago before fuel injection and multi choke carbs most 1/1 cars only had one carb and one exhaust. I would rather use a proper tool then hope to get timing right If you share the crank then both cylinders (combined) can produce more rpm ( thus power) but sharing a crank is not easy...especially given the size/rpm of a RC car glow engine. 1:1 cars and fuel injection/single choke carbs are very different...they are four strokes...slow and lazy but can be more efficient....here we deal with two strokes...totally inefficient but nearly twice as powerful in comparrison. Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 2 minutes ago, Anthoop said: If you share the crank then both cylinders (combined) can produce more rpm ( thus power) but sharing a crank is not easy...especially given the size/rpm of a RC car glow engine. Sorry now you have completely lost me I don`t see the difference between 2 cyliders connected by a crankshaft or a toothed belt apart from the crankshaft being a bit more solid. So if an engine that uses a shared crankshaft can produce more RPM why can`t an engine connected by a toothed belt do the same?. The manic engine runs as a multi cylinder engine not 2 seperate engines. Quote Link to comment Share on other sites More sharing options...
Rory Posted June 2, 2016 Share Posted June 2, 2016 The power will be shared via the belt, although there will be more frictional losses with this setup than having one .36 engine. But its different and interesting and thats why we like it , right ? Maybe you should put 2 manic 36 twins in a car, just to be REALLY different Quote Link to comment Share on other sites More sharing options...
Anthoop Posted June 2, 2016 Share Posted June 2, 2016 4 minutes ago, Ian w said: Sorry now you have completely lost me I don`t see the difference between 2 cyliders connected by a crankshaft or a toothed belt apart from the crankshaft being a bit more solid. So if an engine that uses a shared crankshaft can produce more RPM why can`t an engine connected by a toothed belt do the same?. The manic engine runs as a multi cylinder engine not 2 seperate engines. The Manic is two .18 engines tied together by a belt...nothing solid...tie two cylinders by a single crank then you produce more power simply because the tolerances are lower...let alone the friction... Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 3 minutes ago, Anthoop said: The Manic is two .18 engines tied together by a belt Yeah but working together ie: timed driving through one clutch. Any way I think my question has been answered. 1 Quote Link to comment Share on other sites More sharing options...
Anthoop Posted June 2, 2016 Share Posted June 2, 2016 6 minutes ago, Ian w said: Yeah but working together ie: timed driving through one clutch. Any way I think my question has been answered. You still do not get it though......with a belt/chain/gear there is a certain degree of error...with a crank there is a certain degree of error...tolerance...the crank will/should always have less tolerance the rest. If you really want to think about multiple cylinder two stroke engines then look at how development happened in the motor bike racing world. 1 Quote Link to comment Share on other sites More sharing options...
Ian w Posted June 2, 2016 Author Share Posted June 2, 2016 Mate I do get it 2 working together has got to be better then 2 working against each other or one working by itself. The Manic almost got it but not quite. I am not talking about M/Bikes I am talking about nitro engines in RC cars. Quote Link to comment Share on other sites More sharing options...
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