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Century Helicopter . MTA Hobbies . Model Rectifier Corp

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Speed - Performance - Drag Race > It's HERE
 
 
KenJ
Veteran
Location: Ohio, USA

Other items first?

Actually, the engine and most of the drive train seems to be holding up well!

I have only had one failure, my own fault,

RB innovations recommends lubricating the bearings in the supercharger and I never have. One of them seized up on me last week and froze the SC, burned off the belt, and the heli went SUPER rich!

I was able to get it in without mishap and went to the LHS and picked up a couple of bearings.

Guess I will lube them from now on.

As far as the power hurting the airframe, I don't think that the power increase is that great as to cause something else to destroy itself.

I actually have a modified OS 61 in an R-50 running a tuned pipe and the airframe has held up quite well.

LUBE THOSE BEARINGS!

Team JR
08-06-2003 Over year old.
HOMEPAGE  
 
 
ecoliburger
Senior Heliman
Location: NORCAL

Dont waste your time. 2stroke ic engines are notoriously difficult to run any kind of forced induction. That is why you have never seen a commercial example, ever see any moto-x bikes with superchargers?? Tune pipe's will do the same thing but cost less. I admit it looks cool but it wont work worth a s.... Sorry to put a damper on the excitement, I dont like to see people waste their money. Go ahead with the flames. I should let you know that I have actual experience with forced induction so I am not just repeating crap that I heard some where.
08-06-2003 Over year old.
 
 
patternfly
Senior Heliman
Location: ChicagoLand

ecoliburger, what expirience?
turbocharged honda civic? ?
08-14-2003 Over year old.
HOMEPAGE  
 
 
helicoop
Senior Heliman
Location: North West Ohio

ecoliburger Go check out some of your local fire engines as some have supercharger 2stroke diesel engines.
08-14-2003 Over year old.
 
 
DrGonzo
Heliman
Location:

I would have to agree with ecoliburger. I'm not familier with fire engines which have supercharger 2stroke diesel engines, but i'll look into it. As far as a 2stoke engines working, there are so basic things to know. Most important to this discussion is that the exhaust port and the intake port are open at the same time. In fact the exhaust port closes after the intake port, making pressurizing the combustion camber impossible. Which is the reason for having a supercharger or a turbo. More air and fuel = power. Now this works in a 4 stroke engine because the exhaust valve closes before the intake valve opens, allowing the combustion cumber to pressurize. The only benefit of this product is it maximizes the scavenging process (like tune pipes).

I'm not trying to rain on anyones parade.

more info on 2 stroke http://science.howstuffworks.com/two-stroke2.htm
10-10-2003 Over year old.
 
 
DrGonzo
Heliman
Location:

Ok, i found some info on supercharged 2stroke diesel engines. They work entirely different then a typical 2stroke engine. Most importantly the have exhaust valves, and ur average 2 stroke doesn't.

very neat though, maybe some day they will be more common.

http://auto.howstuffworks.com/diesel-two-stroke1.htm
10-10-2003 Over year old.
 
 
JEraptor
Senior Heliman
Location: Kankakee IL

Port timing

hmmmm that is very interesting, I always knew of the supercharging effect of a tuned pipe but I never thought about it before that the intake port (transfer ports) close before the exhaust port.
It would seem that with the extra pressure given by the supercharger you may end up with a stronger pulse coming back from the pipe into the cylinder. If that were the case then the supercharger would still cause a gain in power but probably not to the extent that it would on a 4 stroke.

In order for the supercharged 2 stroke to be most efficient then a new cylinder would need to be used with better port timing.
It would seem like maybe the roof of the exhaust port could stand to be lowered then. And the supercharger forcing a fresh charge into the cylinder under pressure that would certainly overcome the loss in flow through the now smaller exhaust port. It also seems that the roof on the intake(transfer) port could be raised some.

I have often wondered what kind of timing the ports were at on these engines versus motorcycle 2 stroke engines. It would be neat to compare the numbers in degrees before or after TDC or BDC.

I have also heard of Detroit 2 strokes before, often refered to as a "screaming jimmy" due to their unique exhaust sound.
It is my understanding that they would NOT run without the supercharger and it only puts out about 2 pounds of boost.
But I don't think it is uncommon for those engines to have a blower AND turbo.
I have seen a bare cylinder sleeve before from a detroit deisel and it had intake (transfer ports) all around the cylinder near the lower middle part. I believe the head also had 4 exhaust valves per cylinder but it has been a while and I may be mistaken.
10-10-2003 Over year old.
 
 
DrGonzo
Heliman
Location:

I never considered the extra pressure giving an even stronger pulse back into the cylinder. I guess every bit of power you can gain counts. A good pipe + the supercharger might have a bigger increase then I thought at first. Does anyone know of a web page that might demonstrate the supercharger in action?

Has anyone seen the supercharge installed on a 4stroke? Things like lowering the compression ratio come into play. Maybe adding a couple shims under the head would lower it enough. Forced induction on a carburetor might be a challange. So many questions.

10-11-2003 Over year old.
 
 
supercharge
Heliman
Location:

2 stroke supercharging/turbocharging

I came across this 2stroke supercharger discussion by chance.. Have a look at TS3. I found this on Altavista, and it describes a 2stroke "blown" engine of unique design. You might also want to look at listings for opposed piston 2 strokes (most of which use two crankshafts). Supercharged 2strokes are usually referred to as "scavenged", rather than supercharged, but may be compound blown with a turbocharger as well as the scavenging supercharger. Can't imagine one of these engines in a model helicopter though.
02-05-2004 Over year old.
 
 
RotorX
Key Veteran
Location: London

I thinksomeone poosted this pic a long time ago and every one said it was a fake - looks real to me ?



well cool
02-19-2004 Over year old.
 
 
2 pages [ <<    <     1     ( 2 )    >    >> ]10647 viewsPOST REPLY
PowerHelis . JR-Spektrum . Gyro Hobbies

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Speed - Performance - Drag Race > It's HERE
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