DA100/Mejzlik prop

[Cracky]

Hello, I am buying a DA100 off of a friend of mine. Thinking of getting a Mejzlik prop for it but I am curious on the size. It will be going on a 35% Yak that should weigh 28lbs (stock muffs). Until Max's thread testing props on the 85 I had not heard about the "TH" line of props. I was thinking of a 26x12 or a 27x10 initially, but now I am wondering how the 27x10TH and 27x12TH props would act on that plane. What does the thin profile change in how they pull. Are they better for spinning up higher RPM's or are they just a narrower profile? How does the 27x10 compare with the 27x10TH?

Any information would be appreciated.

Thanks

[Vic3D]

I'm not experienced with the new TH props, but that plane is a little heavy and I would suggest you stick to 27'' props...

[Cracky]

	Quote: Originally Posted by Vic3D
	I would suggest you stick to 27'' props...

I am asking about 27" props......

[Dan_nO]

Hey Fick, you could call or shoot DA an email and ask them about the specific prop your interested in, they have that full line of them, maybe they could answer that question for ya.

[Cracky]

	Quote: Originally Posted by Dan_nO
	Hey Fick, you could call or shoot DA an email and ask them about the specific prop your interested in, they have that full line of them, maybe they could answer that question for ya.

I was going to do that, but I figured that probably more people than just me are interested in finding out about the "TH" props so thats why I posted it in the DA Support Forum. I'm sure that they are pretty busy right now with the 85's going out the door so we'll see if they get a chance to pop in here and enlighten us.

[DATech]

Hello
At 28lbs, you don’t want to over prop the engine.The engine needs to be allowed to develop some rpm/HP.
Recommending props is tricky… A lot of factors weigh in: Flying style, exhaust type, airframe weight, airframe drag/volume, altitude, weather, engine health, etc.
The 26x12 Mejzlik has been very popular on the DA100 lately. Quique uses it a lot and likes the broad speed range the 12” of pitch offers for his style of flying. He likes to go from super slow and low speed 3D to high speed high energy stuff in his freestyle routines. The higher pitch also helps on up wind IMAC maneuvers on real windy days
The Mejzlik TH series props have a different airfoil and plan form.
The 27x10 TH will really pull hard on the 100, but top air speed will be a little less than the 26x12 Mejzlik. RPM is about the same as the 26x12. Both of these should work well on your plane.
Haven’t tried the 27x12TH on the DA100, but I believe it will work well also.
The 27x10 and 28x10 Mejzliks have been the common props for the DA100 for many years and both work very well. Between the two, I would lean towards the 28x10 as there is little difference in load between them. The 28x10 seems to be a little “cleaner” which allows a little more diameter/prop disc with little or no load penalty. Hope this helps a little.
Thanks

[Cracky]

	Quote: Originally Posted by DATech
	Recommending props is tricky… A lot of factors weigh in: Flying style, exhaust type, airframe weight, airframe drag/volume, altitude, weather, engine health, etc.

I completely agree with ya on its tough because everyone is different. Sounds like I need to look at the 26x12 and the 27x10TH. Thanks a bunch!

[niccolo98]

Im sorry for intruding, but I have a question. I am going to fly IMAC with my Extra 260, I have a DA 100 on it (not yet started). Now, I called DA yesterday, and they said I could break it in on a 3 Bladed 25/12. I was going to use this prop for competition aswell. Is there a down side to 3 Bladed props? I heard they slow the planes down in down lines more than a 2 bladed. But the spool up is faster. Please give me your advice, it will be greatly appreciated.!!
Thanks,
nick

[krayzc]

yeah i am here to listen

[DATech]

	Quote: Originally Posted by niccolo98
	Im sorry for intruding, but I have a question. I am going to fly IMAC with my Extra 260, I have a DA 100 on it (not yet started). Now, I called DA yesterday, and they said I could break it in on a 3 Bladed 25/12. I was going to use this prop for competition aswell. Is there a down side to 3 Bladed props? I heard they slow the planes down in down lines more than a 2 bladed. But the spool up is faster. Please give me your advice, it will be greatly appreciated.!! Thanks, nick

Hello
There are basically 3 reasons to use a 3 blade prop: Sound reduction, improved ground clearance, and looks.
When compared to a comparable 2 blade, the smaller diameter of a 3 blade reduces the tip speed/noise. When combined with a pitch increase the rpm can be lower lower than the 2 blade which decreases tip speed/noise even more.
On the negative side, 3 blades generally are not as efficient as 2 blades. The best 2 blade setup will generally out pull the best 3 blade setup. On the positive side, if the plane is not too big or heavy, there will be plenty of performance with the 3 blade and the sound level can be much lower. Important for IMAC sound scores and preserving flying fields.
2 blades are generally prefered for 3D work, but there are many pilots now flying 3 blades for 3D as well.
As for down line braking, other than a few wide blade designs, 3 blades generally don't brake as well. Spool up can also be slower with the 3 blades.
Again, personal taste will be a big factor.

[Imac Kiwi]

I run a Mejzlik 28x10 on my 25lb Comp-Arf 2.6 Extra 330. After starting with a 27x10 Mej and trying a 25x12 Mej 3 Blade, The 28x10 is still my favourite prop.

The 3 blade was quieter and verticle performance was still good, but downlines were faster.

[niccolo98]

well, I think that I will order the 3 Bladed 25/12 Tomorrow with a carbon spinner. It will go on a 35% Dalton Aviation Extra 260! I will break the engine in on this prop, is this ok? or is it going to give me problems? Btw, the engine will be run with greeve's tuned pipes.
thanks
nick