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RE: what mixture of fuel do you guys use?
ORIGINAL: supertib what are you guys running ? RTR small blocks or something ? you obviously don't race 1/8th scale or use any engine resembling a 1/8th race engine Also have you dyno tested said small engines ? do you have facts to backup your claims of them being the most powerful ? If you want to see one being used to set a world speed record then have a look [link=http://www.flyrc.org.uk/record/control_line.htm]here[/link]. |
RE: what mixture of fuel do you guys use?
holy crap, that is awesome! that motor is absolutely SCREAMING!
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RE: what mixture of fuel do you guys use?
ORIGINAL: downunder ORIGINAL: supertib what are you guys running ? RTR small blocks or something ? you obviously don't race 1/8th scale or use any engine resembling a 1/8th race engine Also have you dyno tested said small engines ? do you have facts to backup your claims of them being the most powerful ? If you want to see one being used to set a world speed record then have a look [link=http://www.flyrc.org.uk/record/control_line.htm]here[/link]. I would love to dyno a couple of those engines just to see for myself what kind of juice they have and how they compare to my race .21's, I am always skeptical of any power claims not backed by actual dyno tests with known references I can relate too..... I have a feeling our modern race .21's on 30% are far more powerful then you realize..... |
RE: what mixture of fuel do you guys use?
ORIGINAL: Nitrovein ORIGINAL: supertib ORIGINAL: Nitrovein ORIGINAL: supertib 40 years ago they ran chainsaws with 5 to1 oil mix...now they run 100 to 1 oil mix...go figure... All jokes aside, many things has gotten better over the years, oil, metal, design and so on. It´s just the users that´s left behind in yesterday sometimes... :) Plenty has to do with application... I run modified 1/8th race engines in high stress race environments.... But running the extremely high oil content fuel is not helping the beginner either... So when they get that as a recommendation from the LHS it´s not helping the newcomer... Just thinking here...on a no nitro fuel I guess they need to run a much higher oil content as they just can't pump the volume of liquid thru the engine that we can with 30%............... We have tested 30% nitro with as low as 4.5% oil and had excellent results ......Very shortly we are going to test an even lower oil content...in the range of 2% oil..........But I should say we have some very high grade oils that you normally don't see in the industry... |
RE: what mixture of fuel do you guys use?
it seems that your experience would help me.would try ,thanks.
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RE: what mixture of fuel do you guys use?
ORIGINAL: supertib ORIGINAL: downunder ORIGINAL: supertib what are you guys running ? RTR small blocks or something ? you obviously don't race 1/8th scale or use any engine resembling a 1/8th race engine Also have you dyno tested said small engines ? do you have facts to backup your claims of them being the most powerful ? If you want to see one being used to set a world speed record then have a look [link=http://www.flyrc.org.uk/record/control_line.htm]here[/link]. I would love to dyno a couple of those engines just to see for myself what kind of juice they have and how they compare to my race .21's, I am always skeptical of any power claims not backed by actual dyno tests with known references I can relate too..... I have a feeling our modern race .21's on 30% are far more powerful then you realize..... My little barstock .35 will turn 21,000rpm on the break in prop easily, but I'm sure it would go 45,000+ with less load and enjoy it. Most "sport" engines will turn the same prop in the 17,000rpm area, and this is on 15% nitro and 20% oil! Beyond 15-20% nitro is blown glow plug territory without a set of head shims. Here is a link to the prop power calculator: http://mvvs.nl/prop-power-calculator.xls It's in Excel format. This is the closest you'll get to a dyno for an aircraft engine. |
RE: what mixture of fuel do you guys use?
ORIGINAL: supertib ORIGINAL: Nitrovein ORIGINAL: supertib ORIGINAL: Nitrovein ORIGINAL: supertib 40 years ago they ran chainsaws with 5 to1 oil mix...now they run 100 to 1 oil mix...go figure... All jokes aside, many things has gotten better over the years, oil, metal, design and so on. It´s just the users that´s left behind in yesterday sometimes... :) Plenty has to do with application... I run modified 1/8th race engines in high stress race environments.... But running the extremely high oil content fuel is not helping the beginner either... So when they get that as a recommendation from the LHS it´s not helping the newcomer... Just thinking here...on a no nitro fuel I guess they need to run a much higher oil content as they just can't pump the volume of liquid thru the engine that we can with 30%............... We have tested 30% nitro with as low as 4.5% oil and had excellent results ......Very shortly we are going to test an even lower oil content...in the range of 2% oil..........But I should say we have some very high grade oils that you normally don't see in the industry... When there is less oil and a near 100% tune you put a completely different load on the oil during combustion, so some oil will burn without interference and some will interfere. I made a couple of mixes that worked well in the range between 10.5-11%, they were not as crisp, but would work well for buggy in lower range of racing. I have seen a couple of RTR engine ruined due to low oil, the poor fitment of parts would develop air leaks as the oil couldn't seal properly. One could argue for days if it was the fuel or the engine that was to blame... So if I were to blend fuel to a RTR engine, I would use the most oil that´s possible without getting to bad behavior as in difficult tuning and high temp etc, my Guess is 10-12%... (depending on oil used and owner using it) I think you're on to something there supertib, I have been thinking about what different fuel will do to pumping also. Air is compressible, fluid not so much... As long as the engine is "on pipe" i doubt there is much difference, but it might affect how the engine picks up... It sort of gets to a "flow vs pressure" thing... Just thinking out loud... :) |
RE: what mixture of fuel do you guys use?
ORIGINAL: 1QwkSport2.5r ORIGINAL: supertib ORIGINAL: downunder ORIGINAL: supertib what are you guys running ? RTR small blocks or something ? you obviously don't race 1/8th scale or use any engine resembling a 1/8th race engine Also have you dyno tested said small engines ? do you have facts to backup your claims of them being the most powerful ? If you want to see one being used to set a world speed record then have a look [link=http://www.flyrc.org.uk/record/control_line.htm]here[/link]. I would love to dyno a couple of those engines just to see for myself what kind of juice they have and how they compare to my race .21's, I am always skeptical of any power claims not backed by actual dyno tests with known references I can relate too..... I have a feeling our modern race .21's on 30% are far more powerful then you realize..... My little barstock .35 will turn 21,000rpm on the break in prop easily, but I'm sure it would go 45,000+ with less load and enjoy it. Most ''sport'' engines will turn the same prop in the 17,000rpm area, and this is on 15% nitro and 20% oil! Beyond 15-20% nitro is blown glow plug territory without a set of head shims. Here is a link to the prop power calculator: http://mvvs.nl/prop-power-calculator.xls It's in Excel format. This is the closest you'll get to a dyno for an aircraft engine. I can dyno a aircraft engine no issue.....I don't use any cooling on my dyno and often times have the wrap the engine...... in the past I tried using props for calculating power but found it very limited on what it could show.......so after messing wit pops for a bit I decided to build a real dyno and the rest is history |
RE: what mixture of fuel do you guys use?
Is there an industry standard as to how a R/C glow engine dynamometer determines its data? I mean, will your dyno give the same numbers (with climate taken into account) as someone else's? Last I checked, there was no standard for measuring power output of engines this small.... I am not beating you up just so you know. I'm just asking the question.
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RE: what mixture of fuel do you guys use?
i am new in the hobby, but with every engine i read specs on, the power readings are all in horsepower so i would assume his dyno is reading in hp just like the rest....
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RE: what mixture of fuel do you guys use?
ORIGINAL: 1QwkSport2.5r Is there an industry standard as to how a R/C glow engine dynamometer determines its data? I mean, will your dyno give the same numbers (with climate taken into account) as someone else's? Last I checked, there was no standard for measuring power output of engines this small.... I am not beating you up just so you know. I'm just asking the question. There is a standardized measure of what a horsepower is....However it would be nearly impossible to create a standardized dyno that would be accurate for all engine in all applications..........especially so for 2 stroke engines running tuned pipes......... You see the power a engine creates is very dependent on the load that is placed upon the engine.....To a certain point the power the engine produces will increase as the load placed upon it increases...So the more we load the engine the more power it will generate....Sort of like covering the top of a pop bottle with your thumb and then shaking the bottle, the longer you hold your thumb over the opening the more pressure is built up inside....... The power these engines produce is directly related to the pressure that is generated inside the combustion chamber....back load the engine and it can produce more pressure in the chamber then if it isn't loaded....... So this brings up some very big challenges when it comes to building a dyno......For a dyno to give any relevant information it has to replicate the load that will be placed upon it during its service life..... Not only do we have to replicate the load, we also have to replicate the spool rate...As in the rate the engine would accelerate during its service life....... So if a car took 5 seconds to go from idle to peak RPM the dyno needs to replicate a load that will take the engine 5 seconds to go from idle to peak RPM...........Now for aircraft the spool rate is much less of a concern, but for cars it is extremely critical for the dyno's spool rate to match the spool rate the engine will see in its service life..........Aircraft engines usually operate against a such a load that the engine is working against a dead stall usually at a near fixxed RPM........... So for testing aircraft engines we would want to use a brake style dyno that could could stall out a engine and give us the ability to measure the force it creates, by contrast for a car engine we would want to use a inertial dyno that can match the spool rate the engine would see during its service life........... typically speaking a engine will make more power working against a dead stall then it will during a spool up.......the dead stall load gives the engine more to work against.....So even tho the measure of a horsepower is clearly defined , how we measure and test that horsepower can give us very different readings........Dyno's really are a tuning tool and not always and absolute measure.... Only results from the same dyno system should be compared to each other.....As the mechanical involve can greatly affect the readings we see....especially so with inertial dynoes...... |
RE: what mixture of fuel do you guys use?
ORIGINAL: supertib ORIGINAL: 1QwkSport2.5r Is there an industry standard as to how a R/C glow engine dynamometer determines its data? I mean, will your dyno give the same numbers (with climate taken into account) as someone else's? Last I checked, there was no standard for measuring power output of engines this small.... I am not beating you up just so you know. I'm just asking the question. There is a standardized measure of what a horsepower is....However it would be nearly impossible to create a standardized dyno that would be accurate for all engine in all applications..........especially so for 2 stroke engines running tuned pipes......... You see the power a engine creates is very dependent on the load that is placed upon the engine.....To a certain point the power the engine produces will increase as the load placed upon it increases...So the more we load the engine the more power it will generate....Sort of like covering the top of a pop bottle with your thumb and then shaking the bottle, the longer you hold your thumb over the opening the more pressure is built up inside....... The power these engines produce is directly related to the pressure that is generated inside the combustion chamber....back load the engine and it can produce more pressure in the chamber then if it isn't loaded....... So this brings up some very big challenges when it comes to building a dyno......For a dyno to give any relevant information it has to replicate the load that will be placed upon it during its service life..... Not only do we have to replicate the load, we also have to replicate the spool rate...As in the rate the engine would accelerate during its service life....... So if a car took 5 seconds to go from idle to peak RPM the dyno needs to replicate a load that will take the engine 5 seconds to go from idle to peak RPM...........Now for aircraft the spool rate is much less of a concern, but for cars it is extremely critical for the dyno's spool rate to match the spool rate the engine will see in its service life..........Aircraft engines usually operate against a such a load that the engine is working against a dead stall usually at a near fixxed RPM........... So for testing aircraft engines we would want to use a brake style dyno that could could stall out a engine and give us the ability to measure the force it creates, by contrast for a car engine we would want to use a inertial dyno that can match the spool rate the engine would see during its service life........... typically speaking a engine will make more power working against a dead stall then it will during a spool up.......the dead stall load gives the engine more to work against.....So even tho the measure of a horsepower is clearly defined , how we measure and test that horsepower can give us very different readings........Dyno's really are a tuning tool and not always and absolute measure.... Only results from the same dyno system should be compared to each other.....As the mechanical involve can greatly affect the readings we see....especially so with inertial dynoes...... I know there is a standard measure of horsepower, but as to how it would apply to something running in the ounce-inch scale as opposed to pound-feet scale is what I was concerned with. I've ran an engine here in Minnesota that netted 1,000-1,500rpm less than the original owner got with it in California. Turns out nearly 1,000 feet above sea level needs extra nitro. I wouldnt mind comparing power numbers between a dyno and the prop-power calculator. In the aircraft community, nobody cares about how much horsepower the engine makes but the rpm it turns a given prop at. Of course one can extrapolate how much horsepower the engine makes with a +/- allowance. |
RE: what mixture of fuel do you guys use?
Great reply supetib! :)
I know that some uses data log from on-road testing and program the dyno to replicate that, so they can run each gear on the dyno for development and testing. But this is full scale! But it´s cool to see how the same engine would do on different cars etc... As I have a couple of thousand hours my self on dyno runs I know that static rpm braking is a killer for most engines, kind of like running a boat. Do you (supertib) think it´s possible do subject a car engine to say.. 40.000 rpm under sustained braking? I understand that is a rather vague question, if no one has actually tested it, but what´s your thought... And I do agree that it would be fun to see what a airplane engine is actually putting out, might give some insight to how accurate a prop reading is. :) |
RE: what mixture of fuel do you guys use?
I am actually working on building another dyno...this time I want to add transducers that can data log the engines systolic cycle during operation....... I feel with that data I can better develop the engines efficiency...But right now it is only a theory.......... A few years back I had read an article about a Speedline guy from Germany who had built such a device to read the systolic cycle of the engines during operation...... I Am also looking to setup a very accurate RPM scales that will allow me to see the engines accelerations thru its rotational cycle..I believe I can better develop the balance of the engines with this data....Seeing how it accelerates and decelerates thru its rotational cycle would be quite interesting....................
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RE: what mixture of fuel do you guys use?
Ok.. I may be off-topic again, but what generally makes a glow plug go bad? I got a hotter plug and it went bad within about 10 minutes or less, I switched back to the other plug I had, which was a mid range plug but had also been previously used and probably on its way out anyways, and it quit as well... should I go to a "cold" plug?
The only thing that has changed on the car is that I put a new pipe and yesterday I switched the fuel from 20%/14% to 30%/11%. Is there anything I did that would have made this happen? |
RE: what mixture of fuel do you guys use?
ORIGINAL: supertib ....Seeing how it accelerates and decelerates thru its rotational cycle would be quite interesting.................... The next thing that was done was to determine the angular momentum of the prop used and when this was combined with the torque figures it gave a graph of the change in [link=http://sceptreflight.net/Model%20Engine%20Tests/instantrpm.html]revs[/link] of the prop for all angles of crank rotation. |
RE: what mixture of fuel do you guys use?
ORIGINAL: supertib I am actually working on building another dyno...this time I want to add transducers that can data log the engines systolic cycle during operation....... I feel with that data I can better develop the engines efficiency...But right now it is only a theory.......... A few years back I had read an article about a Speedline guy from Germany who had built such a device to read the systolic cycle of the engines during operation...... I Am also looking to setup a very accurate RPM scales that will allow me to see the engines accelerations thru its rotational cycle..I believe I can better develop the balance of the engines with this data....Seeing how it accelerates and decelerates thru its rotational cycle would be quite interesting.................... I have been looking for some other devices for doing testing in car, like getting good readings on crankcase pressure/vacuum during operation. But I´m having trouble finding anything good enough for that high cycling rate, while not breaking the bank... :eek: Many of the old test regarding delivery ratio might be worth testing again in CFD, well that my idea... Not that it has anything to do with dyno or fuel... :) |
RE: what mixture of fuel do you guys use?
ORIGINAL: downunder ORIGINAL: supertib ....Seeing how it accelerates and decelerates thru its rotational cycle would be quite interesting.................... The next thing that was done was to determine the angular momentum of the prop used and when this was combined with the torque figures it gave a graph of the change in [link=http://sceptreflight.net/Model%20Engine%20Tests/instantrpm.html]revs[/link] of the prop for all angles of crank rotation. thanks for that info...I have been unable to track that down........gotta love how how high the instantaneous torque is......its like we are running tiny impact drivers..... |
RE: what mixture of fuel do you guys use?
ORIGINAL: bikeordie092 Ok.. I may be off-topic again, but what generally makes a glow plug go bad? I got a hotter plug and it went bad within about 10 minutes or less, I switched back to the other plug I had, which was a mid range plug but had also been previously used and probably on its way out anyways, and it quit as well... should I go to a ''cold'' plug? The only thing that has changed on the car is that I put a new pipe and yesterday I switched the fuel from 20%/14% to 30%/11%. Is there anything I did that would have made this happen? A hotter plug has a thinner wire so is more susceptable to damage if used incorrectly...but that is not to say you should use a cold plug. Use the correct plug for your engine/conditions/fuel. Here is a general plug guide- http://www.osengines.com/glowplugs/index.html |
RE: what mixture of fuel do you guys use?
Yeah, actually the idle was a little too rich... I switched to a cooler plug and adjusted adequately, and now to motor runs much better than it ever has, at least in the time I've had it. Runs right around 225-230°f and idles smoothly with a crisp throttle response, not to mention its pretty quick, plan on really getting to open it up tomorrow at my buddys house... that's if I can find a set screw for the front d-cup since the one that was in there rattled out while I was messing around earlier.
P.S.- I am running byrons 30%nitro/11%lubrication fuel.. the car runs much better on it than the "black ops" fuel I had been running that was 20%nitro/14%lubrication. |
RE: what mixture of fuel do you guys use?
http://www.rcuniverse.com/magazine/a...article_id=284
We can always revert back to this ;) I live in a High Altitude region of the country Rocky Mountains and it really does not matter what manufacure fuel I am running tuning is almost daily thingbutthe air temps vary mostly in the spring and fall. Summer time I can almost run the same tune between the weekends I go out to play and way up here it is almost aways meansa richer fuel mix because to the lack of oxygen.When the temps drop or rise I have sometimes had to make a 1/2 turn in my adjustments to the fuel air mix. I use a temp guage as a reference point only because I do not want my engines to over heat. Like to run an engine between 220 to 260 degrees and feel out the sound and smoke trail in between these temp ranges. I fry glow plugs if it hits 300 degrees in most cases from past experience. I have found in my area the higher oil content fuels keep the engines cooler where I live.This is not the same everywhere. When I lived in Georgia I used to love Byron Fuels and of course the Trinity Monster HP. I started out running Trinity MonsterHPFuel 30 % when I first moved out here 8 years ago and they do not sell it anymore from what I can tell because I cannot find it on the shelf anymore. It was my favorite fuel. I used a few others up here like SideWinder and my engines just ran too hot because they had less oil content or less Castor oils. I tried other fuels and my LHS only carries two fuel blends Traxxas Top Fueland Losi Nitrotane these days. They used to carry all kindsof different fuels and it would change all the time now they standerized on what they have onthe shelf. I am going to try the Losi Nitrotane this spring to see how it runs. I do not see much of a performance difference between 20% and 30% nitro and recently dropped down to 20 % nitro because the fuel prices were a huge difference almost $10.00 per gallon. I always have run Medium heat plugs and that is a totally different discussion but you can read this link if your interested found it a very good read. http://www.oneten.co.za/showthread.p...lugs-explained |
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