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Old Jun 18, 2015, 10:44 AM
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Help!
increase OS 46AX RPM for pylon racing

hi rc groups glow engine master!i come from indonesia,and i'm new in the pylon racing engine world,and my question is,how can we increase the OS 46AX rpm without dismiss the engine rule of FAI for pylon race?thanks for your any answer!

greeting from kudus,indonesia
Torabika
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Old Jun 18, 2015, 12:03 PM
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Use an Ultrathrust or Jettstream tuned muffler would be the cheapest option. You need to prop the engine so it runs in the powerband the muffler is tuned to run in though. On a .46, that would probably need to be a 9x7, 10x5, or a 10x6. Without nitromethane, the exhaust system is really the only modification that net the best results.
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Old Jun 18, 2015, 03:03 PM
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It depends on the rules. But if the rules allow it, you can use a tuned muffler on the engine. As 1QwkSport2.5r stated a Jett Muffler or Ultrathrust if you can find one would work. You could try making a Mousse can muffler as well, if allowed by the rules.

If the engine had head shims you could remove some to increase compression, but I don't think that the engine came with shims though. OS might have made a low to no nitro glow fuel head too. That is a head setup to increase compression. It might be something they sell in Europe as the Eueopeans don't normally use nitromethane in their glow fuel.
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Old Jun 18, 2015, 05:22 PM
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thanks for your attention and answer master... in Indonesia rule,nitro was allowed in OS 46 class... but it will not allowed to use tuned pipe... FYI,i use 9x7.5 APC prop,is it right choice?and how if i remove the muffler baffle? or make a mods with the crankshaft?will it increase the power?
Thanks for your answer sir!

greeting from indonesia,
Torabika
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Old Jun 18, 2015, 07:53 PM
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My thinking is to use the engine as it is, stock, no modifications. You can then have a reliable engine. Finishing every heat will likely land you into the top three finishing positions, on the points alone. Now then when you get really good and it finally boils down to you and some other guy fighting over who finishes first or second and it is happening all the time. Then you can start looking into getting some more power. But modifying the engine will merely result in it not being as reliable. Then you start failing to finish for one reason or another.

The guys that try to go the fastest usually wind up not finishing the heats. Plus the guy with the stock engine can turn more lightly in the turns too. So the guy with the stock engine can wind up being the winner a lot of times.
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Old Jun 18, 2015, 09:36 PM
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There are always small basic mods that will help marginally. The rod can be filed to more of a radius, or taper, then polished for strength. A piston can be turned on a lathe from the bottom inside of the skirt, and inside top of the piston. A bit of weight loss is always better. The closing time of the crank can be increased a little but no more than 60 degrees after tdc for sure. It is likely close to that anyway. The hole in the centre of the crank can be a bit bellmouthed, and the inside of the bore can be filled with epoxy (I use solder) and rounded for more stuffing. All these things combined, likely less than 1,000 rpm on a small prop. maybe nothing on a bigger one. Then there are rules too, A few thousandths of an inch off the top of the liner to give more compression, about .015" head clearance. maybe change the inside head shape. Buy a few heads and experiment........
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Old Jun 19, 2015, 10:40 AM
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Right,saturday morning i wanna to try to remove muffler baffle hope it success,,hehehe

Greetings from Indonesia,
Torabika
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Old Jun 20, 2015, 01:16 AM
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hi master....this is my report today...when i remove the muffler baffle,the RPM was increased a little bit than before... and my question are,
1)is my distance of my tachomer to prop. was right?

2)and,i dont really know,how to set the low speed needle of that engine for the best performance,would you teach me how to do it?i read the manual many times but i got nothing

Many thanks for your answer!

greeting from Indonesia,
Torabika
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Old Jun 20, 2015, 06:10 PM
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Getting the Most Power out of the Engine for Q-500 Racing

Quote:
Originally Posted by torabika View Post
hi master....this is my report today...when i remove the muffler baffle, the RPM was increased a little bit than before... and my question are,
1)is my distance of my tachometer to prop. was right?

2)and, i don't really know, how to set the low speed needle of that engine for the best performance, would you teach me how to do it? i read the manual many times but i got nothing

Many thanks for your answer!

greeting from Indonesia,
Torabika

================================================== =================================================


Hi Torabika,


Re: The Tach Question:

*** Try to measure from behind the prop, for safety reasons only. Approx. 8-12/14inches from behind the prop is fine. You can make sure it is calibrated by holding it up to a light bulb. It should read 3600 RPM.

Low Speed idle - Question: Screw the low speed idle out a few turns until it is flush with the edges of the carb itself. Then you can dab a little silicone on the screw to keep it from turning at all. These racing engines have "NO" need for any low speed idle setting screw. By Un-screwing the screw it allows the maximum amount of fuel flow thru carb.


Turning Out Top RPM's - Question:


First off it all depends on the rules and what they allow as to what you can do to the engine. But off the top of my head here are some points I can come up with.

Note: (The baffle being removed will help and increase the RPM's but it may , or may not be allowed.)



================================================== =================================================




The first thing that I would do (or say) is this and this is in my opinion the most important thing you can do, "Breaking In The Engine".....



Breaking in the Engine:


The correct break in procedure can vary from racer to racer and may make or break a racing engine. There are different ways that you can break in an engine. These different variations are what makes the racer have his edge (or thinks he has an edge) over another racer. Some guys will not tell you anything about how they set up the racing aircraft. The point is, this is usually a well kept secret amongst racers due to the fact the their engine secrets are what may make them win or loose a race. You can do some searches on Google and you will find some break in procedures out there on the web.


================================================== ================================================== ====

Engine Running Notes:



The "Break In Procedures" written below are based on using the following Sizes & Items :

1. Break in Prop as mentioned.
2. 10%fuel with 20% oil a mix of Castor/Synthetic blend fuel .
3. Using a 6 to 8 ounce tank.
4. Tachometer- to take readings at different stages.
5. An InfraRed Thermometer - To check the Temp of the head. The temps should be consistent. ( Optional )
6. Run the engine on a test stand.


================================================== ================================================== ====

Running the Engine to Break it In for Maximum RPM's:


1. We run Thunder Tiger .40's here in the US with APC 9x6 props.
"Break In Prop For The Engine"
I take a Master Airscrew 9x6 prop and cut the tips down to about 8-1/4"" long and balance it.


2. Run this prop on the engine at full throttle, but first set the needle valve to somewhere approx. 4 turns out rich. You want it running slobbering rich but turning high RPM's to seat the piston & sleeve. The RPM's will be high due to the smaller sized prop. The smaller prop keeps the RPM's where it would be if it was a regular 9x6 prop but with the excessive rich setting there's plenty of oil to lubricate the engine.

Note: Never Let The Tank Run Totally Dry, As This Will Let The Engine Go Over Lean And This Can Damage The Engine.
WHICH IS NO GOOD.....


3. You want the engine turning the high RPM's but very rich to oil it up all over the inside of the engine[/I].
Run it for about 2 mins. Shut it down and let it cool. Cool to the touch that you can wrap your hand around it without burning your hand. Start it up, run it for another 2 mins and repeat the process until the tank is almost empty.

4. When totally cool, run it again the same way as in step 3. Repeat the process. After about 3 to 4 tank fulls, proceed to step #5.

Note: All Runs on the Engine are Done While Running at Full Throttle:


5. After about 4 to 6 tank fulls run thru it, then start to lean it out a very little bit. Turn the needle valve in approx. a 1/4 of a turn. Let it run for about 30 seconds at this slightly leaner setting, then return it to where it was before you leaned it out and let it run for another 1 min. Then repeat , do this cycle until the tank is almost empty. Don't let the tank run dry....


Note: NEVER LET THE TANK RUN DRY, AS THIS WILL LET IT RUN OVER TOTALLY LEAN AND DIE. WHICH IS NO GOOD.....


6. Repeat step #5
But now turn the high speed needle valve in about a 1/2 of a turn. Let it run for about 30 seconds at this slightly leaner setting, then return it to where it was before you leaned it out. Now let it run for another 1 min at this richer setting. Then repeat, do this cycle until the tank is almost empty. Don't let the tank run dry.... Run approx. 4 tank fulls thru it this way as well.


Note: In both steps #5 & #6 when leaning it out, the object is to bring it out from the slobbering rich running speed in where it sound like it is 4 cycling to a 2 cycle running engine. Repeat this step.


7. Remove the Break in prop and put on an APC 9x6 prop and fill the tank up and start it up. It should still be running with the needle valve out at about 4 turns and should still be 4 cycling. Lean out the needle valve now until it comes out of the 4 cycling into a 2 cycling running sounding engine. Check the prop with the Tach. Run a full tank of fuel thru it again stopping after 2 min intervals like before and let it cool to the touch. Run a second tank of fuel thru it and again stopping after 2 mins and let cool to the touch. Every minute or so pinch the fuel line for approx. 2 seconds to let the engine rev up high.



Note: Allow the engine to cool down to the touch allows the metals in the engine to expand and contract and get the best fit with each other.


8. Run another tank full thru it again for 2 minute runs and let it cool to the touch, but now lean it out a bit more. Tach the engine and lean out the engine until you get about 800 to 1000 RPM increase. Run the engine only for 2 mins. Then shut it down and let it cool. Repeat this until the tank is almost empty. You should get almost 3 - 2 minute runs on it.

9. Repeat the above running one tank thru it, but now lean the engine until you get approx. 16,000 RPM 's out of it.

10. Run one more tank and max out the RPM's to get the most that you can get out of it. Again only make these runs for approx. 2 minutes long. The 2 minutes is approx. the time you will be up in the air racing at full throttle.


11. Throw it on the airplane and go get some practice runs in on the engine. Richen it up a bit for the first flight or two. Then Tach it up to get the most as possible out of the engine then back it down 300RPM's. This is where you want to be give or take an 1/8th of a turn on the needle valve or so for racing.



There are many variations of the above. You can use this as a guide with other ideas from other break in procedure that you may find. This and other procedures will give you an overall idea of what direction to go in. Also remember we run these engines for racing only and that is for approx. 2 min runs. So now Sunday flying around the field for 5-6 mins at full throttle. That's the best way to ruin the engine. after all the hard work and time breaking it in and tweaking the plane who want's to go down that road.




I hope this helps......


"Keep the Throttle Down , the Wings Level and always Pull hard thru the Turns"



Thanks

ElectricEddie
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Old Jun 21, 2015, 03:48 AM
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Superb Suggestion master ElectricEddie!4 Thumbs Up!

a little question master,

Quote:
The smaller prop keeps the RPM's where it would be if it was a regular 9x6 prop but with the excessive rich setting there's plenty of oil to lubricate the engine.
if i break in the engine with 11 inch prop not with the racing prop,will it cause a problem?will it affect the engine RPM after the break in process?because today i alreay break in up my new engine with 11 inch prop

anyway,Thanks for your detail solution Master!
greeting from indonesia
Torabika
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Old Jun 21, 2015, 07:52 AM
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The purpose of the higher rpm/smaller prop is really to break in the rod. The piston and liner breaks in on its own as the engine runs. Running too big of a prop will usually not cause too many problems on a regular run of the mill sport engine such as the AX46. On a performance engine, it could mean the engine ends up down on power or have problems with the rod or both.
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Old Jun 21, 2015, 08:28 AM
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Quote:
Originally Posted by 1QwkSport2.5r View Post
The purpose of the higher rpm/smaller prop is really to break in the rod. The piston and liner breaks in on its own as the engine runs. Running too big of a prop will usually not cause too many problems on a regular run of the mill sport engine such as the AX46. On a performance engine, it could mean the engine ends up down on power or have problems with the rod or both.


Hi Guys,

Yes I agree. I would only add this. Keep Racing Engines for racing only and remember when not racing and practicing for races, only fly for 2-3 mins at most . This resembles the amount of time you would be racing. This keeps the Engine use to these kinds of runs, so it runs good out on the course on "Race Day".

Ed
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Old Jun 21, 2015, 09:07 AM
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I don't know that that would make a difference - running an engine for races only... It is just a sport engine. What I would agree to is when tuning your main needle to peak, make sure if you go past peak (rpm sags), you Richen a half turn, note rpm before the sag, and shut down until engine cools. Engines leaned past peak need to cool down as they get a little over hot.
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Old Jun 21, 2015, 09:19 AM
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Quote:
Originally Posted by electriceddie View Post
================================================== =================================================


Hi Torabika,


Re: The Tach Question:

*** Try to measure from behind the prop, for safety reasons only. Approx. 8-12/14inches from behind the prop is fine. You can make sure it is calibrated by holding it up to a light bulb. It should read 3600 RPM.
Not 100% sure, but to the best of my knowledge, Indonesia has a 50 Hz grid, so that would be 3000....

Brgds, Bert
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Old Jun 21, 2015, 09:22 AM
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Quote:
Originally Posted by torabika View Post
hi rc groups glow engine master!i come from indonesia,and i'm new in the pylon racing engine world,and my question is,how can we increase the OS 46AX rpm without dismiss the engine rule of FAI for pylon race?thanks for your any answer!

greeting from kudus,indonesia
Torabika
Just a quick off topic question: where exactly are you flying?
My wife and me have a small home in Rancamanyar, close to Bandung... I know there is an aeromodelling club in Bandung, only haven't found it yet....

Brgds, Bert
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