MetallicaJunkie

glow planes apc.... gassers wood and CF

ive used vess and xoar wood props under 16" on glow planes and they dont seem to perform as well as APC props

cutaway

Out of dozens of APC's I've had over the years, only a few turned out to be balanced to my satisfaction off the rack. I've been using a lot of 11x4's lately, and every single one was very out of balance. The MAS, wood, and other black nylon's like the Taipan's are no better.

HoundDog

My Feedback: (49)

Don't worry over it ... Fly ducted fans or turbines ... that will solve all the problems associated with PROPS ... LOL ... Then U can worry about over taxing your Credit cards .....

HoundDog

My Feedback: (49)

Ever notice that the Hole seems to be off center on APC?

Tarasdad

I've used both in he past but now prefer wood almost exclusively. They simply perform better on me engines.

cessna172av

My Feedback: (3)

Nylon props are the best because they don't break that easily if you have a prop strike.

Zor

HoundDog,

I can back you up on this one,

Out of 6 (six) APC props Ihave 4 had a center bore / hole as much as 0.010 (ten thou) off the center line of the blades. It was visible by eye.

My first question was "is the hub thinner (less radius) on one side vs the other side?
So I experimented.

I used my prop balancer and balanced one prop horizontally. It was nice and stable in one hoizontal orientation. If I would disturb itwould come back horizontal. If I would turn it 180 degrees it was unstable (CG above the support) would swing around, oscillate like a pendulum and stop horizontal in its first orientation. (CG below support).

I marked the heavy side and tried to put it vertical. It would rotate the heavy mark going down. If vertical in the other orientation (180 deg from previous with the mark on the other side; again the heavy mark would go down.

Give it a kick and make it rotate. Invariably it would end up horizontal with the mark under the supporting axis.

Some tricky measurements revealed one prop 0.010 inch out on one side obviously at 90 degrees with the tip to tip straight line.

I did the same with a second prop and found it 0.006" out.

I did not bother with the two others but I can tell just by eye that they also are out of center.

Who cares? Most never bother to balance their prop.

Zor

lkruse

My Feedback: (42)

Wood or composite, to paraphrase the late George Aldrich, propellers are known for vigorously defending their space.

HoundDog

My Feedback: (49)

Most props need some balancing the bigger they are the more ... to do it right the blades should be balanced first then the hub ... Good luck with it.

Altered1

I run an airboat, and a wooden prop is a big no no. Any water hitting the prop can turn a wooden one into lovely shards. APC for me.

MetallicaJunkie

[8D] he's a legendary amongst a few RC guys

i have a couple of his modded engines thanks to my dad....

airplanejunkie

My Feedback: (2)

I will try and whip anyone who uses a plastic metal or nylon prop and at my age that is a real issue. After 62 years in this wonderful hobby, the most serious accidents have been the loss of an eye with a dried out Top Flight pure nylon prop and multiple fingers lost with the extremely sharp APC reinforced plastic props. The most severe with the later APC. I am so againt them, I refuse to train or help anyone who has such as the above on their model. I even carry a variety of wooden props so I can help others. Yes the preformance may not be as good but does it matter if your sight or thumb is gone???????? Off My soapbox. Thanks Dave George AMA5129 RW 2500

pmerritt

My Feedback: (118)

I agree with Bozarth.  If you need a 60 tooth carbide tipped blade then that's what you use.  I don't know about the rest of you but I started with a 12v electric starter and won't fly without it. 

I don't think I've seen it mentioned but when I am in front of my plane starting it  (which is always in a tail chock)  I hold my starter right in front of the started engine between it and myself until I'm ready to get up and walk around behind the plane.  It's just a logical defense strategy that if for some reason the plane breaks lose or the prop spins off, hopefully it will hit the starter first. 
Home Depot sells some VERY inexpensive CLEAR (or UV tinted) safety glasses that will help save an eye I use when starting planes and then depending on if I need sunglasses or not I either keep on during flight or remove. 

12v starters are a lot less expensive than a trip to the ER. 

on_your_six

My Feedback: (11)

AirplaneJunkie,

Sorry to hear of the injuries as a result of propellers flying apart and prop hand strikes. I too have seen some damage done to a good friend. Always use a chicken stick or a FULL LEATHER glove. I use a starter all the time and have a great deal of respect for the prop arc. Largest engine currently is 55cc.

For my propeller selection, I try to be more scientific about it than most. I have a static engine thrust indication system that I use to measure the pounds of thrust generated on the ground. By comparing several different prop types (Wood, APC, and Carbon Fiber), I can choose the best prop for the engine. Testing does not stop there. I also do some dynamic speed testing. I have two systems 1) a radar gun and 2.) an airspeed telemetry unit that can be installed in the plane.

I make two runs in opposed directions and average the speeds to eliminate the wind speed. Thus I can tell the better propeller for speed. Speed is not the entire answer however. 3D and aerobatics do not rely on speed, so a flatter pitch may be needed.

I have found that Xoar props are quite good for the price. The mejlick props are good. This in no way is an industry wide exhaustive analysis. It is a call for testing, if you want to determine the best for your given situation. Sure the cost of props increases as you try a couple. I would really like to see some variable pitch propeller systems for model planes.

OH, in case you can't find a static engine thrust system, try searching for fish scale.

Zor

An interesting post on_your_six.

I have two fish scale that measure quite well in agreement to each other.
I used them to measure the static ground thrust on my Skybolt.
Engine is a Saito 125 and the prop is a 3 blade Master Airscrew 15 x 7 .
I was not successful because the maximum the scale could measure is 8 lbs.

The thrust of 8 lbs was being reached at about half trottle stick on the TX.
I am guessing the full thrust is around 10 lbs .

From half stick position to full position does not of course double the thrust.

The Skybolt without fuel is just about 10 1/2 lbs.

I have pictures of the tests I made if anyone is interested.

Zor

P.S.: For unknown reason I cannot upload a picture at this moment.

Sunday 22 Jan 3012 at 11:04 EST ___Ya 3012 ___this is 2012 Hee Hee !!!
Fianlly was ableto add the picture.

Zor

Gray Beard

My Feedback: (-1)

I just scored a bunch of STUFF and while going through the boxes I discovered some of those way cool looking white with red tip nylon props. They did bring back memories but also why they no longer make a lot of the props we had in the early years. I even had some of those way cool looking clear plastic three blades we had in the 50s for a short while. Used them on my Fire Baby. They sold them, looked cool, what the hell did a kid know? Just for show I would still like to find one of the aluminum props we had for a while. Those were slick looking and polished out nice and bright. They didn't last long either. The props we have today don't tend to fly apart like the ones we had in the 50s and 60s.
When bad things started happening people wised up. Back then I started using wood when I saw a number of brand new props explode when just having the engine tuned. We have it pretty good today and if we just keep our hands out of the spinning slice and dice we are pretty safe. Wasn't always like that as the Junkie has pointed out.

on_your_six

My Feedback: (11)

You could set your fish scale up with a pulley arrangement to reduce the tension on the line to the fish scale so that you can use your equipment. Look it up in a physics book.

In our experiments, we measure several RPM and thrust readings. I was going to post a graph... alas RCU won't allow it at the moment. I change props and plot another prop. I also found that the readings on a cold engine vary from a warm engine. You would have to take any results like this as approximate for as altitude and air temperature change, so do the results. We record those variables as we conduct the test.

jessiej

Actually, no. Most serious accidents involving props occur after the engine is running. The method of getting it started has nothing to do with it.

Unlike saw blades different prop materials will cause different degrees of damage to flesh and, particularly, bone.

jess

VKGT

Depends on the size of the prop...

I run Carbon on my DA-150 but have a Vess drilled to go on there.

Always ran wood on my smaller gassers which works great. I keep the plastic props on my electrics

EJWash1

My Feedback: (3)

Wood. I prefer wood.

jaka

Hi!
No!
A 12x8 MA is too big for a .52 fourstroke!
A 12x5 or 12x6 RAM or APC are more suitable.

In some cases RAM props are better than APC! MA white tiped props are always worst, sharper edges, sound more and give less performance than every other prop available!

Bozarth

My Feedback: (15)

So do you use a wooden lawn mower blade just in case too? C'mon! Maybe we should all fly with nerf props.

Kurt

flyboy138

I like wood They seem to spool up better for 3D Flying.

WacoNut

I think the point that is trying to be brought up is wood props are safer. People can stick their heads in the sand and say it will never happen to me but once you get a finger or a hand in a prop you will understand. The harder and heavier a prop is the more damage it will inflict. This is why metal props on models were banned years ago.
There is a thread here on RCU somewhere called Prop Bitten, take a look it will scare the crap out of ya One guy is now missing several fingers and most of the function of one hand.
Anthony

Bozarth

My Feedback: (15)

A 10" propeller spinning 14,000 rpms is dangerous - wood, nylon, or composite. Period. Arguing which one is "more" dangerous is moot. Never mind anything bigger!

Kurt