For the "speed" heads
09-27-2011, 09:12 AM
#10
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RE: For the
But their whole nitrous injection system weighs 6 ounces and that is not ideal for 1/2a models but im sure you could trim a couple of ounces off that.
09-28-2011, 11:12 AM
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RE: For the
Like this...
http://www.rbinnovations.com/CEN_CT5_CT4S_Thunder_Tiger_TS4N_Supercharger_p/rbk10553.htm
some old 2 stroke spk engines had super charger type things on them
09-28-2011, 02:27 PM
#15
RE: For the
They use the NOS in the RC cars and trucks to get a extra short time boost for certain situations. You only get a few seconds or so with them. I do not think anyone has tried it on a 1/2a engine yet. I doubt the ball and socket rod and piston 1/2a engine designs could handle the boost as well.
I suppose if you were trying to set a 1/2a speed record for your local flying field, it might be worth it for the big power dive and run through the speed traps, but otherwise the few seconds you get with it before the cartridge runs out doesn't give you too much time to try it.
I suppose if you were trying to set a 1/2a speed record for your local flying field, it might be worth it for the big power dive and run through the speed traps, but otherwise the few seconds you get with it before the cartridge runs out doesn't give you too much time to try it.
09-28-2011, 05:52 PM
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RE: For the
ORIGINAL: nitroairplane
Like this...
Like this...
http://www.rbinnovations.com/CEN_CT5_CT4S_Thunder_Tiger_TS4N_Supercharger_p/rbk10553.htm
some old 2 stroke spk engines had super charger type things on them
09-28-2011, 09:17 PM
#17
RE: For the
When I was in the Army, they had a "tow truck" built to carry the big battle tanks that had a 2 stroke V12 engine that had a pair of turbochargers that fed either 1 or 2 blowers. The engine was about the size of a 9 passenger van. I don't know if it was just a 1 of a kind for test and evaluation or if it ended up becoming a regular part of the Army's inventory.
It was called the "HET".
They also had "Gamma-Goats" which were a 4 wheel drive cab coupled via a U joint to a single drive axle trailer. I think they were 2 stroke turbo diesels too....they really screamed.
It was called the "HET".
They also had "Gamma-Goats" which were a 4 wheel drive cab coupled via a U joint to a single drive axle trailer. I think they were 2 stroke turbo diesels too....they really screamed.
09-28-2011, 11:13 PM
#18
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RE: For the
2 stroke diesels don't work in the same fashion as induction ported glow engines, they're fitted with induction valves on the head, and no transfer ports. Therefore you can actually force a charge into a stroke diesel without it squirting out the exhaust ports.
09-29-2011, 06:55 AM
#19
RE: For the
Squirting the charge out of the exhaust port of a 2 stroke model engine is a good thing. That's what makes a tuned pipe work.
If a blower can force more fuel mixture into the same process, evidently it must work or they wouldn't be selling this stuff to the car guys.
If a blower can force more fuel mixture into the same process, evidently it must work or they wouldn't be selling this stuff to the car guys.
09-29-2011, 09:59 PM
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RE: For the
ORIGINAL: combatpigg
Squirting the charge out of the exhaust port of a 2 stroke model engine is a good thing. That's what makes a tuned pipe work.
If a blower can force more fuel mixture into the same process, evidently it must work or they wouldn't be selling this stuff to the car guys.
Squirting the charge out of the exhaust port of a 2 stroke model engine is a good thing. That's what makes a tuned pipe work.
If a blower can force more fuel mixture into the same process, evidently it must work or they wouldn't be selling this stuff to the car guys.
Yeah, having a read of their thing, there's an unwritten caveat that I read to say 'without a pipe this won't work' as it's really the pipe ensuring that all your fresh charge doesn't just squeak out into atmosphere, so really it's still the pipe doing the work, right?
09-30-2011, 12:36 AM
#22
RE: For the
I've never seen a blown 2 stroke model engine run, all I can do is speculate. For a speed airplane, the bar has been set pretty high without the added weight and complexity of blowers and nitrous apparatus.
The only blower I've been able to visualize for a 1/2A speed plane would be directly driven by an electric motor and mounted behind the fuel tank
The only blower I've been able to visualize for a 1/2A speed plane would be directly driven by an electric motor and mounted behind the fuel tank
09-30-2011, 01:19 AM
#23
RE: For the
The fuel pressure is another issue. If the blower/compressor really works then you will also need to have a proper pump for the fuel.
Simply pressuring the tank with air from the intake, as it looks like in the links above, is not going to be enough at full throttle.
Simply pressuring the tank with air from the intake, as it looks like in the links above, is not going to be enough at full throttle.
09-30-2011, 12:48 PM
#24
RE: For the
The pressure coming off the fat part of the pipe delivers a surplus of pressure and it ramps up with demand.
I don't know what volumetric efficiencies are possible with a 1/2A supercharger, but I'd be surprised to see fuel demand exceed supply. As it stands, I'm working with fuel system pressures on 1/2A engines that require the needle valve to be nearly shut.
I don't know what volumetric efficiencies are possible with a 1/2A supercharger, but I'd be surprised to see fuel demand exceed supply. As it stands, I'm working with fuel system pressures on 1/2A engines that require the needle valve to be nearly shut.
10-03-2011, 08:27 AM
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RE: For the
Actually in a 2-stroke diesel (all early detroit diesels) have a intake port in the side of the cylinder, and a rocker arm actuated exhaust valve in the head.
They ALL have at least a roots type supercharger many have a exhaust driven turbocharger as well feeding the super. (this is actually where early hot rodders got their blowers...6-71, 8-71 etc are all detroit engine models. Mill the tabs off the bottom, swap the rotors around, and add a manifold and different drive/endplates and put on your olds v8 (: )
These engines actually will not run without a supercharger, as there is no upstroke with the exhaust valve open, or intake transfer pressure to blow it out, So the supercharger's function is actually mostly to replace the exhaust gases with fresh air for the next compression stroke. As far as efficiency, remember that there is no fuel in the air at this point so it really doesnt matter if you blow excess out the exhaust. Fuel doesn't come until TDC and at that point it is more like fire shooting out of the injector because the aircharge is already super hot.
This is a loose laymens explanation, as I havent wrenched on one in a few years . Pretty cool engines though with some other neat features, like having a common high pressure fuel rail and using a cam eccentric to manually open the injectors, and all have 2 sets of starter, camshaft, and fuel pump holes and you can replace these 3 components with ones calibrated differently and put them in the other holes and make the engine run the opposite direction! They push a lot of oil out the exhaust though...we always affectionately referred to them as "Slobber" Todd
They ALL have at least a roots type supercharger many have a exhaust driven turbocharger as well feeding the super. (this is actually where early hot rodders got their blowers...6-71, 8-71 etc are all detroit engine models. Mill the tabs off the bottom, swap the rotors around, and add a manifold and different drive/endplates and put on your olds v8 (: )
These engines actually will not run without a supercharger, as there is no upstroke with the exhaust valve open, or intake transfer pressure to blow it out, So the supercharger's function is actually mostly to replace the exhaust gases with fresh air for the next compression stroke. As far as efficiency, remember that there is no fuel in the air at this point so it really doesnt matter if you blow excess out the exhaust. Fuel doesn't come until TDC and at that point it is more like fire shooting out of the injector because the aircharge is already super hot.
This is a loose laymens explanation, as I havent wrenched on one in a few years . Pretty cool engines though with some other neat features, like having a common high pressure fuel rail and using a cam eccentric to manually open the injectors, and all have 2 sets of starter, camshaft, and fuel pump holes and you can replace these 3 components with ones calibrated differently and put them in the other holes and make the engine run the opposite direction! They push a lot of oil out the exhaust though...we always affectionately referred to them as "Slobber" Todd