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Supercharger for a 2-stroke

Old 10-19-2003, 09:10 PM
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Thunderbird5
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Default Supercharger for a 2-stroke

All,
Myself and a friend are going to try something that I have never heard of done. We are going to add a supercharger to a 2-stroke .46 engine. We are using a fan from a computer fan and various parts. Has anyone ever done this? Any tips?

Jake
Old 10-19-2003, 09:34 PM
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jimsails
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Default RE: Supercharger for a 2-stroke

wouldn't using a scoop that took propwash do the same thing?
wait doesn't having the carb in front of the engine behind the propeller do the same thing?
Old 10-20-2003, 04:06 AM
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ZAGNUT
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Default RE: Supercharger for a 2-stroke

welcome to rcu guys, checkout the search function and you'll find loads of threads dealing with this topic.

instead of wasting your time you can use a couple mods that really do work on our engines:

properly adjusted tuned pipe
high nitro fuel
large bore carb with pressurized or pumped fuel supply

for these to work you need an engine with proper port design and timing or you won't see very big gains. the combustion chamber shape and compression ratio may also need to be modified, especially when going to very high nitro fuel.

dave
Old 10-20-2003, 11:26 AM
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adrian-RCU
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Default RE: Supercharger for a 2-stroke

this is how the big boys do it - properly
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Old 10-20-2003, 11:50 AM
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SpaceCase
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Default RE: Supercharger for a 2-stroke

Thats insane. Is that a turbo prop? Who made that? Ima impressed. I have a saito 72 I want to supercharge too. Could you tell me please where, how you made it.
Old 10-20-2003, 01:34 PM
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Default RE: Supercharger for a 2-stroke

Turbocharger on a 2-stroke model engine... well, I thought there's already enough fresh fuel exiting the exhaust without being burnt without such a device.

As said before, tuning your reconance pipe will do you better... without leaning out the engine and wasting fuel.

Here's an article on [link=http://www.twf8.ws]TWF8[/link] about [link=http://www.twf8.ws/new/tech/tip/setup/resonation.html]Tuned Pipes and the Resonance Effect[/link]. The two animations should clear up why a supercharger won't work as intended.

PS: The intake and exhaust port are open at the same time.
Old 10-21-2003, 03:44 PM
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Default RE: Supercharger for a 2-stroke

Wow adrian-RCU !

What about that Saito Supercharger? Who makes it? How effective is it? Additional weight? What does it sound like?

Speaking 4-stroke modifications, outside of adding nitro, what can we do to hop-it-up? Specifically, I would like to change my exhaust on my Saito FA-100.

Please Advise,
Old 10-21-2003, 04:13 PM
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Default RE: Supercharger for a 2-stroke

Hey H- trainer, I agree with you entirely and went back and forth in a previous thread about the inefficiency of super or turbo charging a two stroke. Then I see this and think I must be insane. These superchargers are made by the premier r/c car engine builder in France.


http://www.rbinnovations.com/newsite...percharger.htm

I want to know if they really work or is this a J.C. Whitney B.S. type gadget?

Max
Old 10-21-2003, 04:42 PM
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Flypaper 2
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Default RE: Supercharger for a 2-stroke

Carb is still on the wrong side of the supercharger.
Old 10-21-2003, 05:11 PM
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William Robison
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Default RE: Supercharger for a 2-stroke

Gord:

In the Rootes type blower pictured the flow is around the outside of the rotors, not between. The carb is indeed mounted correctly in the picture.

Bill.
Old 10-23-2003, 03:26 PM
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Default RE: Supercharger for a 2-stroke

ORIGINAL: maxtenet
These superchargers are made by the premier r/c car engine builder in France.
That is not true! Theses superchargers have absolutely nothing to do with R&B Engines. They simply ripped off the name!
R&B's original website is: www.rbproducts.com and there are no superchargers found on that site!
Old 10-23-2003, 03:36 PM
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Default RE: Supercharger for a 2-stroke

My error, I simply assumed that because the name was the same, they were the same company. Don't you have copyright laws over there. In the U.S.A. this would definitely be an actionable infringement and should be pursued right away.

Max
Old 10-23-2003, 03:49 PM
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Default RE: Supercharger for a 2-stroke

Not sure if you're insane or not, but why should that supercharger be different? Laws of physics don't change, the ports weren't touched, so the additional air/fuel mixture will just blow through the engine and out of the exhaust and the engine will run lean.

Well, not even our nationality has copyright on it, or why do you think there is "Swiss Cheese" from Oklahoma? I'm sure Rody can't be bothered spending money on lawyers instead of development of the C6

Maximizes scavenging process of the two stroke engine
We can all imagine that the backpressure won't stand a chance against "10-20 times the normal amount of air", can't we?
Old 10-23-2003, 04:08 PM
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Default RE: Supercharger for a 2-stroke

Looks guaranteed to improve fuel consumption as well! By the way, Swiss is a type of cheese, not a brand name as RB is.

Max
Old 10-25-2003, 05:17 PM
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Default RE: Supercharger for a 2-stroke

By the way, Swiss is a type of cheese, not a brand name as RB is.
Cheese produced in Switzerland is Swiss cheese. In Switzerland, more than 50 different sorts of cheese (taste, smell and look differently with different ingridents and methods) are produced. Only a couple of them has holes. That's why I find "Swiss" better suited as a nationality than an adjectiv.
The US "Swiss" cheese is an insult to every Swiss cheese producer just like cheddar is an insult to every real cheese

BTW, the "supercharger" surely does reduce runtime... not because there's more fuel burnt... but more fuel wasted.
Old 10-27-2003, 09:21 AM
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apoc_metal
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Default RE: Supercharger for a 2-stroke

But shouldn't a supercharger work on a 4-stroke (the second picture above)? In a 4-stroke, both ports aren't open at the same time (right?)? I suppose this would not apply to the topic of the thread tho (supercharger for a 2-stroke)...
Old 10-27-2003, 07:18 PM
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Default RE: Supercharger for a 2-stroke

I don't believe ANY super chargers will actually give a net gain on a one cyl. engine. A semi-well known drag racer, explained to me, something about a roots blower needing hundreds of Hp just to turn the blower, yes , on an 8 cyl monster they take some of that power, and see a net gain, but I think unless your model blower is almost imposable to turn by hand, it will not be making any real compression, or adding a net gain. Or at least not the kind of Hp gain they get with 8 cyls.

What is the YS set-up anyway ?
bobbdd
Old 10-27-2003, 07:39 PM
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Default RE: Supercharger for a 2-stroke

If you use a blower of a size suitable to the engine, you can get a net gain with any piston engine, except a two-stroke with piston controlled ports.

Many of the Detroit Diesel engines are two-stroke, but they have poppet exhaust valves, allowing the exhaust ports to be shut while the inlet ports, piston controlled, are still open. They use the "Jimmy" blowers primarily for scavenging, the way our model 2c engines (and most other 2c engines) use the crankcase's pumping action.

One two stroke that uses a blower with piston controlled ports is the big Faribanks-Morse engine, as used in diesel-electric submarines. But they also have two pistons per cylinder, again, allowing the exhaust ports to close before the inlet ports.

And the "Hot" DDA diesels also have turbos pressurizing the scavenge blower's intake.

So, finally an answer to an earlier question - yes, our model 4c engines can be supercharged to good effect.

And the other question about the YS method - they use the crankcase as a pump, with a rotary valve to control the suction from the carb and the discharge into an air chamber, the big blob you see on the back of most YS engines.

Bill.
Old 09-01-2004, 11:37 PM
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ptechllp
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Default RE: Supercharger for a 2-stroke

Hello everyone,
The supercharged Saito 72 engine is my project. I have a picture posted on my website with some information on it. I will post more soon of it mounted on a plane. Glow engines are not easy to supercharge. a turbo system would not provide consistant enough displacement to maintain the compression pressure and ignition timing. This engine has an actual compression ratio of 7.85:1 The operating compression ratio is 9:1. This is where the engine and glow plug were designed to operate at. I have pumped more displacement into the engine, but have not changed its operating specifications. The platinum in the glow plug has reaction with the fuel being pressurized against it. This has been calculated so that this heat created will ignite the fuel at a specific point in the stroke. I lowered the compression ratio and increased the volume so that the pressure of the fuel against the glow plug would be in the same position as it would be normally asperated. There are many other features to this system. I will post them on my website. The supercharger is not for sale. The cost to research and develop it in 10 days cost my company over $3500. It looks sharp and you can hear the gears of the blower whine at a distance.
Thanks for your nice comments,
Troy Legner www.precision-technologies.com look under the cool jet engines link. I can't remember where I put it.
Old 09-02-2004, 12:38 AM
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William Robison
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Default RE: Supercharger for a 2-stroke

Troy:

I just figured out where the fifth bearing is in your blower.

Thanks for the email and the link. Your site is interesting, if you weren't a manual shop you could probably build and sell several of the blower kits. But then you'd have to make a larger one for the 1.20 and the 1.50 and the... No end.

And you'd still get requests for two stroke versions.

Bill.
Old 09-02-2004, 05:11 AM
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Default RE: Supercharger for a 2-stroke

Superchargers and turbochargers cannot work efficiently, only in the simple two-stroke engines that we use for models (and weed trimming, chainsaws, Etc..).

More elaborate two-strokes; almost invariably Diesels, employ both to give outstanding power outputs.

These are engines that have sleeve-valve intake ports, masked and unmasked by the reciprocating piston and usually four poppet type (normal valves) exhaust valves, all placed in the cylinder head.

Since these engines have a lot of control over the 'overlap' period and since they ingest only air, there is nothing to prevent the effective operation of any type of supercharging device; be it exhaust driven, or crankshaft driven.

In all true Diesels, fuel is injected into the combustion chamber, at very high pressures, when the piston is close to TDC, at the end of the compression stage.

It immediately self ignites to produce the power-stage, pushing the piston down.

Such are the Allison-Detroit-Diesel engines that are in many busses, trucks and military vehicles (M113 APC - not what you think, Armored Personnel Carrier).
The Orbital Diesel engine is also similar in operation.


This technology cannot be used to make supercharged model two-stroke engines, since its cost will be very, very high.
Old 09-04-2004, 04:52 PM
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Default RE: Supercharger for a 2-stroke

ORIGINAL: DarZeelon
(M113 APC - not what you think, Armored Personnel Carrier).
wrong! it really means Aluminum Piece of Crap...and the engine had a wonderful tendency to shred the blower belt at the worst possible time leaving you with lots of smoke but no "go"


dave
Old 09-04-2004, 06:54 PM
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Default RE: Supercharger for a 2-stroke

This is very true. Actually I have done all three but individually. PLus I think my two Jett's .50 & 90 cover all three or darn close. With just the fuel alone is a big boost with 30%nitro.
ORIGINAL: ZAGNUT

welcome to rcu guys, checkout the search function and you'll find loads of threads dealing with this topic.

instead of wasting your time you can use a couple mods that really do work on our engines:

properly adjusted tuned pipe
high nitro fuel
large bore carb with pressurized or pumped fuel supply

for these to work you need an engine with proper port design and timing or you won't see very big gains. the combustion chamber shape and compression ratio may also need to be modified, especially when going to very high nitro fuel.

dave
Old 09-04-2004, 10:30 PM
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DarZeelon
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Default RE: Supercharger for a 2-stroke

ORIGINAL: ZAGNUT

wrong! it really means Aluminum Piece of Crap...and the engine had a wonderful tendency to shred the blower belt at the worst possible time leaving you with lots of smoke but no "go"


dave
Actually, we were told it broke its supercharger shaft, it you advanced the throttle too quickly...
And yes, It is Aluminium and it could be perforated by M-16 bullets, at close range...
Old 09-04-2004, 10:44 PM
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Default RE: Supercharger for a 2-stroke

What I don't understand is why do we constantly read about this issue? I agree it took me a while to ingest the information about why 2 strokes are not able to be Supercharged or Turbocharged. I am not a physics genious but I do understand the facts. Nor am I a gear-head, but after seeing the engine jewelery I would not mind having one of these "turbo/superchargers" on my plane for the sound and the conversation brought on buy this mechanism. It is goofy isn't it?

Lets rest the issue. Give me the $200 bucks you would spend on this supercharger just so I could tell you to buy a YS110 or 140 Dingo and run them on 30%nitro! Thats all you'll need. Then I'll put your $200 bucks to better use by sitting in Hooters drinking brew and eating chicken wings.

The Turbo prop rig shown in the picture is for/from the Turbo Raven correct? Is it CS with variable pitch?

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