As most people are well aware, shed loads of development is done during war time, and, during both world wars, aircraft where the Main benefactors of this.
As I understand it, one big problem was performance at high altitude for aircraft, leading to all sides having " exhaust driven turbines" on several aircraft.... But opting for "externally powered turbines" due to reliability ( and I assume cost), likely for reasons you have outlined previously.
Perhaps someone who is familure with aircraft can enlighten us on the models etc.
I said ( possibly 1956, and issued a rider that I was not sure of the date), I would now go to say that it was "mid 60's" when several European manufacturers had Compressor's on 2 strokes.... Both driven of exhaust gas, or another power source.
Considering " exhaust gas powered turbines" where winning the Indy 500 in the early sixties, and running since before then) I fail to understand why it is so hard to accept that many factories where able to get working
examples of their own.....
I believe the badges are made in Vietnam.
Some people belive in god , they often have trouble like you are experiencing.
Show some evidence , rather than just speculating and demanding everyone follow your beliefs.
another difficulty with turbing a 50cc 2t is the need for a full flow oil supply around 5 to 10 l per minute. now you need a sump and oilpump
P38 was one of the first turbo supercharged aircraft, to get reliability the turbine was half exposed to the airstream, WW2 was very early days.
My neighbours diary says I have boundary issues
Nice attitude.
So the P38 was the first turbo supercharged aircraft...... And it worked........
Just because you cannot find something on the Internet, does not make it untrue. Just as just because you find something on the internet, does not make it true.
I have pictures of several engines ( 2 and 4 stroke) that where "way way way ahead of their time " ( so to speak, or perhaps that means some people are way way way BEHIND the times....)
Come on man, people rant and rave about synthetic fuels, and so on, but the reality is that almost every aircraft engine in WW2 was run off synthetic fuel...... Extracted from Coal...... You could make it today if you felt the need.
Internal combustion engines have been chuffing their way round the world since 1883..... The first one was made less that 200km from where I am sitting....
I'll make a deal..... If Teezee finishes his Plenum....and posts PRINTED dyno graphs, as well as a video of the runs, I will post 5 pictures of an Austrian exhaust gas propelled turbine boosted engine and 3 pictures of a German exhaust gas propelled turbine boosted engine,( I am starting to see why the termsTURBO and SUPERCHARGE where brought into use in the English Vernacular ) before 1966.
The one positive thing we can all take from the latest "shit talk" portion of this thread is that someone else is contributing..... Makes a nice change.
If the childish abuse continues, I'm more than happy to chuck everything in PD again, and infract the arse of anyone who continues with the crap.
Enough, eh?
Can I believe the magic of your size... (The Shirelles)
Kreidlers 50cc 1965 world record set at Bonneville used a mechanical driven supercharger of the vane type. It used two disc valves for induction.
http://www.elsberg-tuning.dk/images/65sckreidler.jpg
And from the other side
http://www.elsberg-tuning.dk/images/...dkreidler2.jpg
Sketch of the vane type supercharger.
http://www.elsberg-tuning.dk/images/...percharger.jpg
Great stuff Sonic, so now we know for sure, not turbocharged in 65, like I thought and unless there is some evidence to the contrary, not before that either I would think.
Your post and pic's have filled out the picture of 50's and 60's Kompressor bikes....................
Thanks for a post with supporting references that can be followed up. I just love the engineering that goes into those little Kreidlers.
I have been having a poke around on the site and its very interesting. http://www.elsberg-tuning.dk/
Ok we have fallen into a few traps for beginners. The flywheel on the left is 71mm ID and the one on the right 68mm, which means the poles are different sizes. And as magnetic flux and therefore voltage generated is affected by how close the pole is to the magnets in the flywheel a small pole in a large flywheel would give poor results if they were mixed up. We also added a smoothing capacitor for better measuring accuracy of the DC output with the digital Volt meter.
We have tried several coils and found we could get 100 turns of 1.0mm wire, 200 turns of 0.8mm or 410 turns of 0.6mm wire on a bobbin.
We need 0.8 mm wire with an area of 0.50mm2 and 420 turns for 14Volts DC at 2.5 Amps. So the only way to get anywhere near that, we will have to wind two bobbins with 410 turns of 0.6mm wire each, and wire them in parallel. That would effectively give us an effective 0.85 mm diameter wire for 0.57mm2 area, and hopefully that will give us the Voltage we want and handle the current needed.
Next week we will get Bucket to make them and see how it goes.......
Let us please not get off track this time.
many is the time that all tuners have fooled them selves (myself included) that just because an engine revs clean with out load, then if it is simply a matter of jetting to get it to run correctly under load.
This, in my experience is simply not true.
The reason I asked you to post a picture of your dyno graph is that with that, I can get a better idea of what is happening.
You just posted a series of seemingly random numbers that did not really help.
I have over a decade of dyno experience Teezee, in 3 different countries, and I believe I can identify many problems as long as I am given the correct accurate information .
I think you yourself conceeded that there was a possibility that the problem was "signal strenghth at the jet", something I alluded to when the subject of "blarrggghs" came up.
This onomatopoeia type description I can identify with, and, along with your description of when it is happening (midrange), is pretty much on par with what happens when you "over carb" an engine.
Which, a symptom of which is the same as your experiencing now, caused by a weakened signal strength at the main jet....... Which is why you have such massive main jet, when in all logic, just basing the jet size on realistic flow rates, there is no way in hell that jet could be flowing correctly, as you would only get a few laps on full throttle and run out of gas!
All the bigger jet is doing is making it easier for the fuel to come through the larger jet (which offers less restriction for the air/fuel mixture), as the weakened signal strength is too low to force the fuel through the smaller jet.
The amount if fuel that does actually get through is more or less the same with either the smaller (correct size) carb with the smaller jet, or the (too big) sized carb with the massive jet.
I have seen literally dozens of people turn up to a dyno with massive carbs and try to get me to jet it......the end result is always the same..." erm, now let's try a carb 10mm smaller", straight away, it carburates correctly, and changing the main jet actually has some effect, as well as needle settings.
I still believe you problem is the same, and since your whole concept is about over coming the carb size restriction, Why is it so hard to see that there is every possibility that the plenum is simply too big?
It won't take much work to quickly reduce the size of the Plenum a pair of bucket racers socks jammed in the plenum will do for a test run.
The amount of oil you talk about in the Plenum, if I am right, will diminish anyway, as if the engine carburates correctly, such things (standoff) are reduced, and in any event, take a look at a pre 95 Honda RS125 (no air box) after one race the back of the frame is coated in oil, from where the engine "blargggs" it is even worse when it is ridden by a novice and spends too much time under 8,000rpm.
Thank you for taking an interest in the plenum, gives me a chance to talk about it again……
BMEP - the professional engine developer and tuners yard stick...........
Brake Mean Effective Pressure (BMEP) is a very effective yardstick for comparing the performance of one engine to another, and for evaluating the reasonableness of performance claims.
The definition of BMEP for a 2-stroke is: the average (mean) pressure, which if imposed on the piston uniformly from the top to the bottom of each power stroke, it would produce the measured (brake) power output. For a 4-stroke you have to take both cycles into account.
Note that BMEP is purely theoretical and has nothing to do with actual cylinder pressures. It is simply an effective comparison tool. You can even use it to compare a 125cc 2-stroke's performance to a large 4-stroke diesel train engine. BMEP is a universal yard stick for piston powered internal combustion engines, a quick Google will turn up heaps of information on BMEP, the way to use it and the science behind it.
Brake Mean Effective Pressure (BMEP)
2-Stroke BMEP = (HP x 6500)/(L x RPM)
4-Stroke BMEP = (HP x 13000)/(L x RPM)
L = Displacement in Liters i.e., 80 cc = 0.08, 125 cc = 0.125 Liters 1 ci. = 16.39 cc
As you know, a graph is not possible with Johns dyno.........................
And so I was surprised that the value of the data was not recognized or appreciated when I posted those numbers. They were published so you could make a valid comparison between the conventional setup and plenum using the BMEP approach, the way professional engine tuners might if that's all there was to work with.
and also, so you didn't have to just take my word for it.
So in an effort to not fool ourselves, lets leave the twin sisters Faith-Based and Hope at home, give their big brother Dogmatism the slip and bring our good friends Open-Minded and Science to the party so they can run the numbers I gave you from the plenum dyno session (the engine setup was ex opening at 86deg ATDC, 24/28 diffuser carb and Honda RS125 chamber).
BMEP of my 125 at 21 hp and 9,500rpm = 115 psi Conventional Carb Setup (Inlet closing 85deg ATDC)
BMEP of my 125 at 20 hp and 8,500rpm = 122 psi Plenum Chamber Setup (Inlet closing 35deg ATDC)
The difference in inlet timing came about because I mistakenly thought shortening the inlet duration was what was required to cure the blarrrrs. But the problem was cured by lengthening the inlet tract inside the plenum. And I did not have the time or energy to change the inlet timing once again before I went to Johns to dyno the bike with the plenum fitted.
So for my bike 115psi BMEP conventional and 122psi BMEP plenum and both using the 24/28 diffuser carb. Now what does that tell you............
The better BMEP number for the plenum suggests the plenum has potential and could be a winner if the inlet duration is extended. Only suggests mind you, it could be the better filling at the lower rpm or the shorter inlet duration suited it, or the pipe was more suited for the lower rpm. But I suspect that a later inlet closing point with the plenum will release some more power, more power than could be made with a conventional carb setup.
I will have to test to find out, and along with the new bike and engine I am making a plenum setup that can be quickly interchanged with the conventional setup and both will have adapters to try different carb options for true back to back tests on a dyno.
You can chose which Dyno I use if you pre-pay them for all of the time needed and I will FedX you printouts of all of the results …………..
In the mean time there is a video clip of the bike being warmed up, bearing in mind what you said about the RS125 carb spit back, I think the clue as to why the 24/28 diffuser carb needs a bigger jet when fitted to the plenum than when its fitted conventionally is there, look carefully and you might be able to see it too? http://www.youtube.com/watch?v=YxiEo8cgopg its also impressive how quickly the throttle can be opened without the motor stumbling too.
Your thoughts?.............
I have paired the original post down and highlighted it so others, who maybe less experienced than you can more easily see that the data was there, and check the maths if they like.
I am surprised an accomplished engine tuner would think using BMEP as an evaluation tool is wiffle……........ and there was a lot of information in that original post.
Ok, I would Like to graph it out, and compare it with your non plenum run, as well as some others I have.
can you please post the data you have as it come from Johns computer, and I will convert it to a x and y graph myself, then over lay each one, so I can get a better picture of the shape of your curve ( since we are talking about BMP)
The P4 we use has a facility to graph out a curve based on the type of data Johns prints out, so I will just have to enter in the data, and can print out a graph for you. That is the theory anyway, I have never tried it, it will be a first, but I am told it will work.
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