Walfam

My Feedback: (1)

My mentor , a master flyer is flying an older EMC2 and at a contest last year we saw some guys using 3 blade and 4 blade props. The reason was that the extra blades slowed the plane down considerable at low rpm. He tried a 4 blade and it
made a world of difference, and on the upline when he hit the throttle that plane jumped to attention. Since I started in pattern last year (sportsman flying a home built tiger 60 and working on a safhir) I have been calling the pattern for my mentor and I just finished the judging school to learn more, and I have found pattern guys to be very competitive but even more important helping one another.

so with that thought in mind I hope this information might help.

Bob Pastorello

My Feedback: (198)

You're exactly right. I ran 3 bladers all last season on the Arresti's in Masters, and received lots of positive feedback about the downline. Down side is you need LOTS of motor to make it work right....the OS 1.60 is doing the job, so will the YS 1.60, some are even using the OS 1.40 RX w/ 4 bladers and having great success.

THey work - but MANY will not "experiment" because of the $100 it takes... a spinner and prop will get you there pretty quick....

miniCAP

My Feedback: (3)

I have been wanting to try a 3 or 4 blade prop. What would you guyz recommend for a CA Model Zafiro with a YS 110?

Xrod

My Feedback: (2)

On my Giles 202 with ST2300, I went from a 18x8 two blade, to a 16x10 three blade. This was mostly to get a little more ground clearance (broke a lot of props). My experience was that overall performance and power were similar, but the three blade did not slow down as much. I suppose due to smaller disk size. My thinking in using this size was that the MA 16x10 is affordable and the biggest they make. Two blade to three blade, go down an inch, 18x8 to 17x8, decrease diameter, go up in pitch, 17x8 to 16x10. This is probably the wrong way to select a prop.

Neo02

I fly a 15.5x12 4-Blade on my OS140RX, can't comment on the downline braking effect because I never tried a 2-blade prop, but 4-blade props are definitely quieter and my model made 89 dB in 3 meters' distance, measured during the last contest of 2004. Noise emission is quite a concern here in Switzerland and I must say that 4-blade props keep the noise at an acceptable level. Ground (and in my case, water) clearance was also an issue.

Regards
-Fabrizio

Jeff-RCU

My Feedback: (4)

I'm also using the 15.5x12 4 blade with my os1.40 on a bolly muffler. Very quiet and very good braking.

Surefire

My Feedback: (1)

What sort of RPM are you guys getting on the OS1.40 with the 15.5x12 4-blade?

Thanks

Jon Carter

patternflyer1

My Feedback: (11)

Hey Jon. If you want to try a four blade, I could let you borrow the 15.5x12's and tru turn that I inherited from Jevan. I'm thinking about trying them out this weekend on my 140l in the ariel to see how it reacts.. He tried it on the Zen and it was much quieter but he claimed he didn't have the upline power. I thought he did though. I would be glad to lend them to ya... You're flying the os 140 like he was aren't you? Are you still flying the Shadow this year? Do you have any idea when the schedule for this year comes out? I kno, lotsa q's. Sorry, not trying to hijack the thread. If the weather holds out and I try it on the Ariel this weekend, I will post the results I find. C ya, Krishlan

Neo02

Hi Jon,
to be honest, I have no idea but I will measure and get back to you as soon as possible. You might want to check out the other thread about noise abatement [link=http://www.rcuniverse.com/forum/m_2581760/anchors_2590692/mpage_1/key_/anchor/tm.htm]here[/link].

Regards,
-Fabrizio

Jeff Page

My Feedback: (2)

Wrong ..... its the disk area created by the prop diameter... 2 blades or 100 blades(as long as the relative wind is back driving the engine)

tl3

My Feedback: (2)

Hello, since we're on the subject of three blade props, does anyone have any direct experience with three blades and the 3m 170? I've got a Focus II / 170 combo I'd like to try a 3 blade on.
thanks in advance, Ty

www.rcaerobatix.homestead.com

ZDZ Engines, RC Showcase

rodney tanner

I have been using a 15x13 3B wide on my OS140 RX, which I find preferable to the 15.5x12 4B. The 3B seems to give more bite at this altitude (Mexico City 8,500 OSL) and better breaking on the down lines. Bur overall I have to say I prefer the 17x12 2B, especially in high winds.

rcacro

Is it the disc area or the total area of the the prop blades? With a 100 blades you would have a solid disk. I would think this would have more of a breaking effect than a 2 bladed prop. ie the more blade area the greater the breaking effect.

An old pattern flier who has not yet faded away

quist

My Feedback: (198)

One of the reasons for the 4 blade prop is constant speed. I tried one on my Rev Pro and I have to say not only was it a lot quieter then Jason Shulmans Electic but it slowed my plane down on all lines.

I am running the webra 160 with the es comp. 160 pipe. on 15% cool power. It tached at 7650. the guy that gave me the prop is running an OS 140 on cool power 30 pro pattern and it is the same rpm.

Troy Newman is running it on his YS 160 but I never asked him what it was turning.

Troy Newman

15.5-12 4blader

160DZ
30% Cool Power heli fuel
NMP (Central Hobbies) Header
ES DZ Pipe
YS Glow plug

I have one motor turns it at 8500. My other motor which is newer turns it at 8700.

Quique used this prop on the 160DZ at the NATS and is has some good attributes. There are some bad things too. It eats lots of power. You need a motor to haul it. Its a pretty good match to P-05 and F-05.

patternflyer1

My Feedback: (11)

Hey Troy....
So would you say that the it wouldn't do any good for me putting it on my 140L on the ariel to try the advanced schedule? I won't waste my time if it will put to much strain on the motor with no benefit... Thanks (as always) for your time!!!!!!!!
Krishlan

Surefire

My Feedback: (1)

Thanks for the #'s guys - I have been running the 15.5x12 4-blade and I wanted to do a sanity check on my numbers. My setup is an OS 1.40Rx, ES pipe and Magnum #1. With this setup I am getting ~7700RPM on the ground.

Troy - Man! That DZ must be eating it's Wheaties!

Thanks

Jon Carter

Troy Newman

Krishlan,

Hey dude! My opinion is its way too much load for a 140L. I'd say try the 14.5-12 or the 13.8-10. I ran the 14.5-12 on a pretty healthy 140L back in late 99. I was running Magnum #2 which is like 35% nitro and it was a bit of a load on a Typhoon 2+2 that was 10lbs. Now keep in mind I was at 5000-6000ft in Denver depending on which model field I was flying at that day.

Jon,

Yep the 160DZ's have some really good MO! I have been really happy with them this past year.

Wildstyle

Hi
A Question for the guys running 3 or 4 bladed props on their 140RXs, what size props are you using with what nitro percentage, exhaust system and at what attitude? RPM also would be helpful.

At the moment I am using a Bolly 590R muffler with 15% Nitro and a 17x10 2 blade APC on my 140RX, which runs very strong. Although the down lines and overall flight is quite fast, so I am thinking about going to a multi blade prop but don't know what size (I was thinking 15.5x13 3B).

Also what are the 3 or 4 bladed props like for vertical compared to 2 blade? Anyone like to comment on their experience.

Thanks Anthony.

Alfonso Garcia

Anyone test Master Airscrew 3 Blade 16x10 in a OS 140RX? My Larimar landing gear is a little bit shorter for the 17x12 APC.

Alfonso.