Rotax 582 RPM

[Henni]

Hi everyone,

The original owner of my Mizer is of the opinion that I am far too conservative with regards to safe RPM usage of my engine.

1. What should my maximum static RPM be on the ground? (I can achieve this by adjusting the pitch on my prop)

2. What is the max RPM that the engine can safely be operated at continuously in the air?

Thank you for any information.

Henni

[Mogas]

Howzit Hennie
I don't operate a 582 so not sure of the rated max RPM, I'm sure someone will post it soon.
I just wanted to mention that you MUST adjust the pitch for max rated RPM. The 582 being a 2stroke has a definite power band and will not achieve anywhere near rated power if not in the powerband. If too much pitch is set you will not have all the power available for when you need it one day to get you out of the K K

[Rudix]

Hi Henni,

The 582 develops MAX HP @ 6500 rpm so you would want that to be your max in the air. Depending on plane (faster planes unload more) you would look at about 6200-6300 rpm on the ground. The "red line" is 6800 so there is a bit in reserve but you do not want to exceed that.

I agree with Mogas, you need to rev the 582, like most 2 strokes, at the correct rpm to get the rated power. The max continues rpm in flight is difficult, I would say about 6200 rpm but I am sure there would be people with more experience than me.

I found on my 618 it is quite happy to run at 6200 rpm for long periods but at 6200 the fuel consumption is BAD!! (about 22l/h)

I would love to see your Mizer fly, maybe we can make a plan for a few air to air photos ?

Have fun and fly safe,
Rudi

[John Young]

.... I would say about 6200 rpm ....

Agreed - 6200 rpm static and 5500 rpm cruise is optimum.

Regards
John ZU-CIB

[DieselFan]

It varies alot and also depends on gearbox surely? I get max 5800 on ground and 6000 at 90mph bar in. Cruise is around 4100rpm.

[Henni]

Hi guys,

Thanks for the info. I'm rather sure that I'm there as it is right now, even without being re-jetted yet from the coast. Also, in flight I try to keep it below 6000RPM which then seems to be about correct.

Whilst we're on the topic, would you please suggest jet sizes for operation at our elevation?

Rudi, I operate from Siera Romeo. My Mizer is the older MKII version, so not as impressive as the newer versions. But she really flies beautifully and I am satisfied for the moment.

But you're welcome for some photo shoots - never been there before.

Thank you in advance,

Henni

[Henni]

Hi everyone.

Seek and ye shall find!

Well, I searched & I found:

582
Jet Needle 11G2 - Circlip position #3
Needle Jet 2,72
Main Jet 165 at sea level
Main Jet 158 at Highveld
Idle Jet 45

Thanx Morph!

Henni

[Henni]

Hi all,

Another seek & ye shall find:

Posted: Thu Feb 01, 2007 4:20 am Post subject: 582 with 4:1 E box

--------------------------------------------------------------------------------

DF

I had a similar set up. Aerotrike Safari, 582, E-box with 4:1 ratio. Bought the aerie with 6 blade Ivo prop. I never really flew this prop, and replaced it with a 3 blade 72" NC prop. I can't remember the exact pitch, but it was around 25 to 27 degrees. Static run-up gave me 6,400 rpm, and would see 6,800 on climb out. Cruise, one up around 5,000 rpm, and 5,400 two up at Highveld altitude.

From what you are describing, you are not running your 582 anywhere near optimum, and most likely it is due to the prop pitched to course.

Reduce a degree at a time until you see around 6,400 on static run up. Don't make the mistake of thinking that you are saving fuel or running better at low revs. Two strokes are designed to perform at their peak at high rpm. Rotax specifies 6,800 for max 3 minutes and 6,500 max continuous on this engine if memory serves me right.

Best
Barry

Thanx Barry & apologies for asking what has already been discussed in detail.

I'm busy reading through all the older posts and am being enlightened in the process.

Regards to all on an otherwize very quiet forumn,

Henni

[DieselFan]

Hi all,

Don't make the mistake of thinking that you are saving fuel or running better at low revs. Two strokes are designed to perform at their peak at high rpm. Rotax specifies 6,800 for max 3 minutes and 6,500 max continuous on this engine if memory serves me right.

Henni

I will repitch a tad less, altho my fuel consumption is very good at moment with about 8-9l/h one up. Sunday at MTOW and after 160miles averaged out to 12l/h. Cruise was higher at 4500 as I was two up and full tank. I can't pitch for 6500 on take off as it runs too fast at my max straight and level. I've got a 4:1 E, Arplast 4 blade. Admittably my climb is not wonderful at around 800 one up and 600 two up.

[Hot Stuff]

Impressive Dieselfan, I further think is you changed the colour of the prop, the fuel consumption might improve some what. (Then again I could be wrong)

[DieselFan]

Impressive Dieselfan, I further think is you changed the colour of the prop, the fuel consumption might improve some what. (Then again I could be wrong)

But a car in red is always fast? Unless I make it black like the batmobile and adjust the compression so that fire shoots out the exhuast, then forget about propwash on a still day look out for burning leading edges.

Oh well, I'll leave that up to you to perfect You can practice with all the trikes which just sit in your hangar collecting dust.

[ICEMAN]

But a car in red is always fast?

Precisely why fire engines are red...... red is faster , everybody knows that

[Morph]

Henni,

do you have EGT probes and gauge on the plane? EGT's to me are the best thing since sliced bread on a 2-stroke. It really gives you a good indication of where you are getting the best cooling due to fuel/oil mix and RPM. I found that my little 503 would run very happily at full throttle and 6250rpm. She ran cooler than at 5800 for example. By using this I managed to find the best cool cruise rpm and the best climb rpm and I pitched for that.

Dieselfan, just remember adding pitch to a prop will reduce your max rpm , increase the cruise speed and decrease the climb rate and increase fuel economy, but at what cost. What is also does is adds loading to the motor and loading increases the EGT. Better economy also means less fuel and it needs the fuel in the oil to help keep cool. There is a happy medium that needs to be found.

Finally my EGT probes also told me I had a particular hot-spot at about 4800rpm. I thus used to reduce below or above that rpm on long cruise decents.

[Henni]

Morph,

Yes it does have - not sure whether it works properly. I will really monitor carefully on next flight. During previous flights I zoomed in on the water temp gauge as warned by Johan Froneman & previous owner, but water temp stays well within safe operating boundaries. I'll have to cultivate the habbit of waiting for proper operating water temps before take off though...

My biggest concern for high RPM would be crank failure - as I understand from an A/P this normally happens mostly at high RPM. Not sure if a happy EGT setting will guarrantee that this will not occur.

If so, it would be nice to run at higher settings as it would mean much higher cruising speed for me.

Regards,

Henni

[Morph]

Henni,

Yes crank is is likely to fail at very high RPM, but I suggest that the risk is above normal operating rpms. There is a document somewhere that details wear on a 2 stroke and by running at lower rpm's with a higher loading i.e. high pitch, dramatically increases the wear on the motor. Your best indicator IMHO on the 2 stroke is the EGT, the cooler the better. CHT in the 582 are masked by the fact that the engine is water cooled, so if you have a water temp guage you don't need CHT or vice-versa. I only used CHT/water temp to warmup before takeoff. Once at operating temps after that I monitor EGT's especially on climb out, cruise and very definately decents.

I'll try to find the document