Mejzlik Prop CHoices

[KrisW]

Hey guys .. Glad to see the DA line finally get in here. .

Here's my quandry. . .

I'm running the 28-10 Mejzlik on an engine, but can't use it in IMAC bacause the engine turns it so hard to pull the plane, so it rips very easily.

Soooo. . . I try the Biela 28-10. . okay, the plane is quieter, but MAN I have to really use tons of throttle to pull the plane, and the uplines SUCK. . .

So. . I'm thinking. . 28-12 2-blade Mejzlik. . turn a few less rpm than the 28-10, but have more speed and energy built up even at lower rpm, and allow the engine to spin a bit easier than the 28-10 Biela.

This is going on my MX-2 that weighs 30.5 lbs.

Like I said. . the 28-10 Mej pulls it great. . but it's way too loud. I also tried the Vess 27 a and b . . neither was right for the plane.

[Flyinrazrback]

Try a PT Models 28x10, they are lighter, pull as hard or harder, and are a lot more quiet than the mejzliks.

[KrisW]

	Quote: Originally Posted by Flyinrazrback
	Try a PT Models 28x10, they are lighter, pull as hard or harder, and are a lot more quiet than the mejzliks.

The Mejzlik is only loud because I have to turn up the rpm to get the speed necessay. If I do not have the speed, no matter what prop I use, being quiet is an afterthought, and any 10 pitch prop I run will have to turn that same rpm to geive me the energy the plane needs . .so any prop out there is going to rip.

So, I need speed and pulling power. . then I can back off the gas and use less rpm. I already have a "quiet prop" with the Biela, but it just does not pull hard or fast enough with a 10 pitch blade. That's why I'm considering the 12 pitch Mejzlik. I'll lose 300-400 rpm, but the speed will increase, so I can use the engines power, have lower rpm, but keep the speed up where it needs to be.

Besides, the PT prop only comes in 10 pitch. . I'd still have to rev it up, wouldn't I?

[SUPERFLYJAY]

BIELA PROPS MAKE GREAT PAINT STIRRERS

[KrisW]

NO BRAND WARS !!!!!!!!!!

[Plane Wrappers]

I have found the PT model's to just the opposite.
I replaced a 32X10 Mejzlick with a PT32X10 and found it to rip much easier.
The PT prop is much wider at the base and I thought I would be quieter. Nope.
I promptly put the Mejzlick back on.
It would be a big expense with purchasing a new spinner, but did you ever consider a 3 blade.
If quiet is what you are going for and keeping the same pulling power, That may be the best option.

[Shawn Berkheimer]

Kris, there are only 1 way to quiet prop noise and that is to reduce tip speed. Going up in pitch will load the engine more and bring the rpms down. The problem with that is you will most likely bring the engine out of it's optimal power band and thus loose vertical. the other way is to reduce diameter, this will have the effect of reducing tip speed and load so what happens is higher RPM and the same noise level unless you go up in pitch also. again this will load the engine and you are likely to loose some power here as well. The 28X10 Mej really is about the best all around prop you can get for the 100cc engines. IMO it is unrealalistic to think that you will be able to change to a quieter prop by increasing pitch without loosing some vertical. IMO again what needs to happen here is that you need to learn how to fly the throttle to the point where the prop is always loaded. When the prop ripps you are not making any more thrust then if it were backed off just enough to keep it from ripping.


Shawn

[Flyinrazrback]

You might consider an Engel 28x12, 28x14, or 29x12 . They pull awesome and are as quiet as any three blade out there even though they turn up well. I was running a 31.5x13 on my 150/157 and it is an awesome prop, my buddy has acquired it somehow from me and running it on his Dalton/157 combo. You can get them direct from europe, or from Hover Hobby in Sanford Fl. I am surprised more people here in the states fly them, guess everyone is stuck on menz and mejzlik. PS, the 3w carbon 27x11 is also a great imac prop and very quiet as well.

[KrisW]

well said Shawn. The prop is going on the BME 110, and then onto the 115 when it gets here. . so the power band will get stronger with the 115. Right now the engine is tach-ing about 6900 static with the Mejzlik, and probably unloads another 6-700 rpm in the air, going right into the "Rip Zone". Taming the RPM by 400 would keep the prop out of rip territory most of the time, yet with 20% more pitch provide much better dynamic thrust while flying above 25-30 mph. It would not 3D worth a damn, but I am not gong to be doign 3D with this plane. . Strictly PATTERN work, Folks. . Think lines, and 45's and graceful stuff that requires pull and speed and energy. . . not acceleration out of a hover.

As for the Engel props, they have very thin blades, and rpm well, but IMO do not have the pull of the Mejzliks.

3-blades are NOT an option. They are just too inefficient to use with a 100cc class engine on a 30 lbs plane.

Right now the prop rips terribly, and the plane still seems to want more speed. Soo. . . add some pitch. . . lose a few rpm to get rid of the rip, and maintain and possibly gain some speed and energy.

That's the theory, anyway, and since it's only theory, I'd reallylike Huff or Daves input on this one.

Think of this as considering the difference between a 32-10 and a 30-12 on a 150 IMAC plane.

[Vic3D]

Everyone just needs to come down here in PR and fly with us. No one complains about the noise. Mufflers and ripping props all day long!

[madmax]

Hi guys, pulling this into the engines forums as the conversation seems more appropriate here. thanks dudes.

[Flyinrazrback]

The engel 31.5x13 pulled harder for imac than the mejzlik 32x10 I tried. Not sure if that is the case for the smaller sizes of props, but what I noticed on the 150cc size prop. I would think an old style zdz 160 would be the ticket for this size plane considering its only a pound heaver than a DA 100, but thats just me.