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40 Size Props

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Old 11-15-2010, 04:34 AM
  #1
thailazer
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Default 40 Size Props

I've used Master Airscrew props for a lot of years but since getting cut pretty bad on one, I've switched to Thunder Tiger Cyclones. It is a much safer prop as it needs no filing or sanding to remove flashings, and it has much duller leading and trailing edges. Haven't noticed any real performance differences and am wondering if anyone else has been concerned with how sharp the Master Airscrews are? Am also wondering if there is any performance data out there on 40 size props.
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Old 11-15-2010, 06:12 AM
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Default RE: 40 Size Props

I use wooden props for the same reason.

Tom
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Old 11-15-2010, 10:02 AM
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Default RE: 40 Size Props

It's standard practice to scrape the TE of MAS props with a knife or razor blade (scrape, not cut) to remove the flashing left by the mold.

And NEVER flip a prop by hand!
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Old 11-15-2010, 10:05 AM
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thailazer
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Default RE: 40 Size Props


Quote:
ORIGINAL: MinnFlyer

And NEVER flip a prop by hand!
Hmmm, that is one of the reasons for this post. I hand prop with the Cyclone all the time as my OS 35AX starts so easy, but would never even consider it with a Master Airscrew. And that is after sanding the Airscrews well.
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Old 11-15-2010, 10:08 AM
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Default RE: 40 Size Props

That's like saying, "I feed my pet cobra by hand because he's never bitten me"

Just not a good idea
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Old 11-15-2010, 10:23 AM
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Default RE: 40 Size Props

I usually hand start my engines, but for glow engines, I always use some sort of chicken stick, usually rubber so as not to damage the prop. Gas engines I hand prop, but use a heavy leather glove. I also dull the sharp edges of the plastic/composite props.
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Old 11-15-2010, 02:40 PM
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Default RE: 40 Size Props

I have to agree, if you are hand flipping your prop, sooner or later it will bite you no matter what prop you use. I use Master Airscrew and always scrape the edge to remove the sharp flashing and always use a starter or chicken stick. Good Luck, Dave
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Old 11-15-2010, 05:46 PM
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Default RE: 40 Size Props

Imust be crazy or something, I flip my MAprops bare fingered without any problem...granted, Ionly do it when the engine has died on the flight line and Idont wanna drag it back to the table to where the starter is.. the only cuts I have gotten were from me dinkin around in the shop playing with one off the engine..
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Old 11-15-2010, 08:11 PM
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Default RE: 40 Size Props

All prop flippers hold up their hands.

Now let's count fingers.

;-)

Tom
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Old 11-15-2010, 10:41 PM
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Default RE: 40 Size Props

An engine this size can easily be bump started. Prime the engine with igniter off the plug, set to medium idle attach igniter and give the spinner a good twist clockwise. If the engine is a little wet it will bounce off the compression and fire, running in the correct direction. Fingers never cross the path of the prop.
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Old 11-16-2010, 08:18 AM
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thailazer
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Default RE: 40 Size Props

After reading some of the posts on this topic, I realized (hence my "hmmmm," MinnFlyer) that in my 20 years of flying prior to by decade long break I hardly ever hand propped. Didn't start doing it (albeit only occasionally) until this last year. So today I went back to using the starter 100% of the time. I've seen what cut up hands look like and it isn't pretty. Even with bump starting, everything has to be just right to be safe. The starter helps minimize the number of things that have to go right to keep the red stuff in the bag.
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Old 11-24-2010, 08:50 AM
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Default RE: 40 Size Props


Quote:
ORIGINAL: thailazer

I've used Master Airscrew props for a lot of years but since getting cut pretty bad on one, I've switched to Thunder Tiger Cyclones. It is a much safer prop as it needs no filing or sanding to remove flashings, and it has much duller leading and trailing edges. Haven't noticed any real performance differences and am wondering if anyone else has been concerned with how sharp the Master Airscrews are? Am also wondering if there is any performance data out there on 40 size props.

I've not seen any prop data wrt to max rpm, and thrust per rev or per 10,00rpm

Its generally thought thatr APC have the best efficiency / thrust ratio.

its generally thought that MAS is more flexible and a bit noisey

Its generally thought that RAM is underated

Iguess Bolly is also good although I have never tried one let alone seen one.

I use mostly JXF wood props and APCon the .46size engines and 12x6 on the .53-.55 engines. (OSAXrange)


Oh and I never flip a prop over with my fingers, not even for priming. I use an electric starter at all times.
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Old 11-24-2010, 02:58 PM
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Default RE: 40 Size Props

I don't have any data, but the quality wood and APC props do pull harder than MAS. I use those on smallish engines and APC on mid size, Wood on all larger scale.
Regarding flipping with fingers on those small 2 strokes-Use the APC's so when it does bite-It's a nice-Clean-stitchable wound
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Old 11-24-2010, 08:37 PM
  #14
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Default RE: 40 Size Props

Who gets fingers cut up from flipping the prop? Every injury I've seen that took more than one small bandaid, and the only one I've ever had, has happened AFTER the engine started running, not from starting it. The worst I've had from hand starting is a backfire that made a small cut once. Since then, I only hand flip wood props and use a chicken stick on composite props. But it's a mistake to think hand starting is the danger...the real danger comes after it starts running!

People have gotten bad injuries from props using electric starters...because it is not the starting that is most dangerous.

Jim
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Old 11-25-2010, 04:33 PM
  #15
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Default RE: 40 Size Props

These post remind me of an old u control saying, " the best thing that ever happened to MC COY engines was SULLIVAN starters " Think about it, it fits. ENJOY !!! RED
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Old 11-25-2010, 09:22 PM
  #16
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Default RE: 40 Size Props

For the best possible cuts from engines .049 and up, use the old Top Flite white nylon
or the old Tornado yellow or white nylon props.[sm=crying.gif] Back in the day my engines always
seem to run a little better once these props had a tint of red on them.

I always sand the flashing off molded props and I always sand the trailing edge if it needs
it or not just to be safe. And don't forget to check and/or balance your prop after you
touch them up. Back in the day MA props were pretty clean props and all you had to do
was hit the trailing edge a little and you were good to go. Whatever the new process is
that they went to about five or six year ago (the last time I bought props) you have a little
more work to clean them up. I like balancing props so the extra work is no big deal, just
part of the process. Wish I could find another Highpoint Balancer.


Ron
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Old 11-26-2010, 01:33 PM
  #17
jaka
 
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Default RE: 40 Size Props

Hi!
Generally APC is considered making better props than Master A.
But The Brittish RAM prop and Graupner Cam prop is even better in some applications, as for instance in Q-500 racing using 10x6 props and .40 engines. Here these props have the upper hand in comparacy to APC.
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Old 12-23-2010, 01:41 PM
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Default RE: 40 Size Props

I have been hand-starting engines since the 60's but will not teach someone else to do it because I don't want to be responsible if they get careless. I do wear a glove on the big engines, however. The key is NEVER flip against compression. Always flip against the stroke.

My advice to newcomers: Buy a starter.
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Old 12-24-2010, 09:59 AM
  #19
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Default RE: 40 Size Props

56 years ago, my Fox .35 (complete with nylon TF prop) bit me and I still have the scar. Since then it's been a chicken stick or electric starter. But I always sand the prop edges anyway.

Happy Holidays guys/gals.
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