drifter rpm warning?

[Guest nunans]

saw this placard on a 503 drifter on the bay.

 

does anyone know what its about ive never seen a warning like that befor does it apply to all 503s?

 

AUSTFLIGHT AVIATION

 

Avoid continouos operation between

 

5800rpm and 6400rpm.

 

 

[fly_tornado]

Is the cruise speed on a 503 5800rpm?

 

 

[facthunter]

It's not unusual to avoid operation ( continously) at certain revs, or a range. I believe these sorts of warning should be displayed more often where the problem exists. Pilots could inadvertently be running at exactly the wrong RPM setting. Nev

 

 

[Patrick Normoyle]

It's out of the rotax manual, max RPM 6400, no more than 5 min continuous for take off etc. cruise RPM up to and including 5800, the Rotax 582 says the same thing. Tats what is says in my Rotax manual anyway.

 

 

[Guest nunans]

Ah ok. so its just a warning taken from the engine manual. no worries, i read my manual to be 6800 max 5 min and 6500 cruise. in other words avoid continuous operation between 6500 & 6800.

 

depends on the engine type no doubt

 

 

[fly_tornado]

I know with the 503 the single carb has a lower RPM rating than the dual carbs.

 

 

[facthunter]

Some of these engines had crankshaft failures (drive end). I don't think the warning is issued for nothing. Nev

 

 

[ausadvance]

my aircraft runs smoothest at 6100 rpm, on Wayne fishers advice, he said it is fine to operate their wand that was issued early in the peice fudge to harmonics though was found not be be an issue, engine has now has 200 hours on it in that rev range and no issue, nor any sign of issues forming

 

 

[Guest Maj Millard]

Nunans...flew 650 hard hours on a 582 well within that rpm range, with no problems and no nasty harmonics. The 503 didn't have a history of crankshaft failures, but the early 582s did. Don't know if 'harmonics' within certain RPM ranges had anything to do with that. They beefed up the crankshaft, but we kept operating the same way and the failures stopped. The twin carb 503 Vs the single carb runs much smoother, and many of the earlier 503s ran 3-blade props Vs the four blade Broglas that are common now. A four blader will run smoother than a three-blader generally. I would suggest that those RPM operating ranges suggested in the Rotax manual were more for elimination of heat buildup than to eliminate destructive 'harmonics.'..........................................................Maj...

 

 

[Rotax Service Centre]

saw this placard on a 503 drifter on the bay.does anyone know what its about ive never seen a warning like that befor does it apply to all 503s?

AUSTFLIGHT AVIATION

 

Avoid continouos operation between

 

5800rpm and 6400rpm.

Hi To all..With regards this placard concerning RPM operating range.during the 90's we experianced quite a few crankshaft problems with both the 503 but more so with the 582 engine.Rotax identified detrimental vibration harmonics at various RPM range,depending on whether the engine was fitted with a pull start or electric starter(addition of ring gear added weight and changed inertia of crank).The crank was nitrided,centre gear for rotary valve modified and later vibration damper fitted..We placed placards at the time to avoid continues operation within these critical ranges,however I dont believe I have noticed any current warnings by Rotax..In the case of the Stutbraced Drifter the aircraft is so heavy that operating out of this range would be difficult to say the least.

 

As usual these are my opinions based on my experiances and not necessarily those of the Factory..Regards Richard..

 

 

[ausadvance]

thanks for the advice richard!

 

 

[Turtle]

Hi To all..With regards this placard concerning RPM operating range.during the 90's we experianced quite a few crankshaft problems with both the 503 but more so with the 582 engine.Rotax identified detrimental vibration harmonics at various RPM range,depending on whether the engine was fitted with a pull start or electric starter(addition of ring gear added weight and changed inertia of crank).The crank was nitrided,centre gear for rotary valve modified and later vibration damper fitted..We placed placards at the time to avoid continues operation within these critical ranges,however I dont believe I have noticed any current warnings by Rotax..In the case of the Stutbraced Drifter the aircraft is so heavy that operating out of this range would be difficult to say the least.As usual these are my opinions based on my experiances and not necessarily those of the Factory..Regards Richard..

Great to still have good advice from someone who knows thanks Richard

 

 

[facthunter]

There's a minimum front seat mass on the 582 strut braced, and probably on the others. Any time you have a tandem seat and a pusher especially you are looking at Big C of G possibilities . You rely on balancing the engine with a person and persons are different from each other. Nev

 

 

[Head in the clouds]

... and persons are different from each other ...

Do you have a reference for that?

 

 

[facthunter]

It's in the POH. A weighted cushion is used under the front seat "occupant' If they are too thin.. I was going to indulge in some levity, but in aviation that affects balanced conversation/discussion. Nev