What pitch to use on a 582 3 blade 68" Kiev 2.58 gearbox


19 posts in this topic

Posted

I got the engine running today.  The wooden propeller from the 532 wouldn't fit, so I started off with my new 68" Kiev three blade propeller.  The instructions said that the starting point for a 582 should be 11-14, so I set it at 12.  The old 532 Tachometer seems wildly off, so I have connected up a Tiny Tach.  I warmed up the water temperature, increased throttle to get the EGTs up and then pushed it up to wide open throttle, but only got to 3400 RPM.  I am running a 2.58 gear box.  I am not sure if it is the throttle assembly or the propeller that is giving me the issue.  So can anyone provide at least some idea of what pitch should be used?  I tried the test twice and still need to break in the engine.  I am currently running the gas at 100:1 in addition to the oil pump as recommended by Rotax in the 582 installation manual.

TIA

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Posted (edited)

Questions from one who knows nothing about Tiny Tachs, except that there seems to be 2 models of them:  Do you have the proper one for your ignition system, and is there a setting you change on it?  Does your engine sound like 3400 or 6800 rpm?   What does your TT show for idle speed?  I am sure that you may get some better comments than I can give.   EDMO

Edited by EDMO

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Posted

I wrapped it around both plug wires for a single cylinder and set it to 180, which is supposed to be for to sparks per revolution.  Since I am rebuilding this plane, am not used to a 582, I am not sure what 6800 RPM should sound like, but the engine doesn't sound stressed to me.

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Posted (edited)

I wrapped it around both plug wires for a single cylinder and set it to 180, which is supposed to be for to sparks per revolution.  Since I am rebuilding this plane, am not used to a 582, I am not sure what 6800 RPM should sound like, but the engine doesn't sound stressed to me.

I guess my best question was "What do you show for idle speed?" - Somewhere around 1500 to 2000?  or are you showing half of that?   These engines get shaky when idled too slow.   If your TT shows 750 to 1000 and the engine is running smooth, then you may be reading half the rpms.   If your TT is showing 1500 to 2000 idle, then you may have throttle - timing - prop pitch adjustments to make.   I don't know if that "180" setting is correct, since some 2-smokes fire 2 times per revolution - once at top stroke and again at bottom stroke, others fire only at top stroke?  I don't know much about Rotax engines!  ???  Probably any 2-smoke flyer on here can give you better answers.   EDMO

Edited by EDMO

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Posted

I would raise the idle speeds that you mention Ed to around 2500 for a smooth idle, maybe down to 2200 RPM.  At 1500 you would probably be getting lots of gear box chatter.  JImChuk

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Posted (edited)

I would raise the idle speeds that you mention Ed to around 2500 for a smooth idle, maybe down to 2200 RPM.  At 1500 you would probably be getting lots of gear box chatter.  JImChuk

I'm sure you can give him better answers about the Tiny Tach, Throttle and prop pitch than I can.  I just answered because nobody else was answering.  EDMO

Edited by EDMO

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Posted

It is currently reading in the 1300s at dead idle and I haven't adjusted yet....not very smooth there...but it has occurred to me that maybe it is firing once per revolution instead of twice...especially since 3400 * 2 would be 6800.  I am going to try and find someone with an optical tach today to verify.  I don't want to decrease the pitch of the propeller until I figure it out because that would be BAD.  The old tachometer was running off the lighting circuit and was reading awfully high, which I had attributed to the change in engine, but maybe it is more accurate than I had first presumed.  But if that is true and the engine is dead idling in the 2600s, it seems awfully rough for that rpm.  The investigation continues....

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Posted

The 582 spark plugs fire twice per revolution.   If you think you have the tiny tach set correctly, I would try wrapping the sense wire around just one spark plug wire to see what you are reading.  Although the optical tach should tell you what's going on as well.  I doubt very much that you are actually idling at only 1300 RPM or making only 3400 at full throttle.  I don't think I've ever seen a two stroke with a gear box and prop mounted that could idle that slow.   JImChuk

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Posted (edited)

I currently have the tiny tach wrapped around both just below the forward mag.  I thought this could be the issue yesterday, so I removed it and wrapped around a single plug wire closer to the plug and was reading the same RPM.  Additionally, I currently have it wrapped five times, because I read, I believe on this site to shoot for five, but according to the instructions, it said three to four times, so I tried that, also without any change.

Edited by TSoftware
Correction

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Posted (edited)

My best guess is that your tach is not set right.  I've only used the tiny tachs that you couldn't adjust.  I did buy one of the adjustable ones, and couldn't get it to work right, and ended up sending it back.  Maybe I just got a bad one.  If you are able to sit in the plane and use the brakes, are you able to hold the plane from moving at the 3400 RPM?  Doubtful  that your brakes are good enough to hold the plane in place at full power or probably even close to that.  They probably can at a normal/actual 3400 RPM.  JImChuk

At full throttle, tied off to a scale, you would probably be showing over 300 lbs of static thrust with a 582.  I've seen reading of 305 to 310 with several different props.  Got a scale?  :-) 

Edited by 1avidflyer

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Posted

I had everything blocked when I tested...I have a guy with an optical tach coming out today and will see what it is actually turning at.  I am just hoping that I haven't done any damage if it is the tach that is the issue.  I did two warm ups / full power tests based upon the tiny tach, so, if this is the problem, I would have warmed the engine up way too quickly.  I guess we will see.

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Posted

Well, verified the tach.  I had to back the prop back down to a 3 to make RPMs, but have it in the 6400 - 6500 RPM range now.  The Kiev instructions suggested a starting point of 2-4 for a 503 and 11-14 for a 582.  Think I will go do the break in on the 582 now and maybe I can get ahold of the prop guys and the engine guy to figure out exactly what this means.  I am afraid that it means that my "new" 582 is making closer to 50HP instead of 64, but we shall see.

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Posted

Just a FYI, as the subject has been well covered before.Dont be tempted to fly a 2stroke If the prop is under pitched,make sure your revs are actually what the tacho says. A fine pitch and a cool day can send your EGT's into meltdown territory,If you ever experience this,a little choke will drop the temps enough to get you safely back on finals.A little much pitch will just mean the engine isn't producing the maximum power,possibly the safer option?

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Posted

Most people running 2 strokes suggest running a static RPM of 6250 or maybe even a bit less.  The engine/prop will unload in level flight and RPMs will go up from there.  Like Dusty said, lightly loaded prop = high EGTs.  And then maybe silence.  (terrible sound)  I would rather make a bit less HP and be a bit safer.  JImChuk

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Posted

I am set at 6100 (static) and it works great.  If you havent dont it yet, manually verify your gearbox ratio.  Whats is stamped on the outside isnt always what is on the inside.

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Posted

My question is actually about what setting you used on the protractor.

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Posted

What are the EGTs at wide open throttle?  This will tell you A LOT about how the engine is loaded.  If you have the proper jets per the chart and your only getting EGTS of under 1000-1100 you have too much pitch in the prop.  Watch them in the mid range as well.  On a 2 stroke you really need to be able to correlate the RPMS and EGTS to get a better picture of how the engine is being loaded.

I would turn the idle up a little as well unless you running a clutch.  If you have a clutch then your golden at 1400 or so RPM at an idle.  If you dont then you need to get the idle above the point that you have that nasty gear box chatter and vibration.  Dropping down a jet size on the idle will help you as I dont know of an engine that has ever burned down at an idle. 

:BC:

 

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Posted

The EGTs got up to 1200.  My issue is that the directions for the prop indicate that a 582 should start at 11-14 and a 503 should be between 2 and 4.  Since the prop is set in the 503 territory, I am wondering what that says about how much power the engine is making.  That is why I am trying to find anyone else who has this prop installed and attempting to find out what  they have the prop set for with the protractor.

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Posted

If they got up to 1200 I would say you need more pitch.  Set it for around 61-6200 static otherwise you are going to have run away EGTS when that prop unloads as soon as you start rolling.  Run the break in procedure then go from there.  I would target 1100 on the EGTS and make sure the water temps dont go over 180 or so during the break in. 

Final pitch will be set once you start flying and figure out what it likes in the air.  I keep mine around a MAX of 6500 once I start rolling and on climb out.  Anything more than that and your falling back on the Tq curve and just beating the air.

:BC:

 

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