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Proper prop balancing

Old 02-16-2009, 07:45 PM
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skysfallin
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Default Proper prop balancing

Got a problem with a Big Stick60. Having had the engine shut off right after take off three times this past saturday, the last time resulting in the landing gear removing itself from the fuselage. Did some investigating and found air coming through the fuel line. I know the system is tight so I must assume the air is from vibration. No room to cover the tank in foam. I bought a little smaller tank today and wrapped it in foam . I hope this helps. My question is, Reduce vibration and thus reduce airation in the fuel. When it comes to props where should material be removed from? Front, back or tip. I have the magnetic balancer and it is quite sensitive. I was wondering how to balance the spinner as well. Any suggestions would be greatly appreciated . Love this forum.
Old 02-16-2009, 08:05 PM
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Default RE: Proper prop balancing

You can sand a little from the heavy side - front and back both. don't change the airfoil. usually it doesn't take too much. You can also paint the light prop with some clear paint. My experience is that the bubbles in the line are usually from a leak somewhere not from foaming duew to vibration. There can be a leak inside the tank just behind the stopper where the brass tube transitions to the tube going to the clunk.
Old 02-16-2009, 08:36 PM
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w8ye
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Default RE: Proper prop balancing

Remove material from the back side of the prop near the tip for balance

As said your air bubbles bubbles that soon are coming from the fuel line
Old 02-16-2009, 08:39 PM
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Default RE: Proper prop balancing

I use a little different method. I like to spray paint my prop tips to increase visibility while the engine is running. All I do is just add a quick spray to the lite blade until it balances.
Old 02-16-2009, 09:11 PM
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Default RE: Proper prop balancing

Here's the balancer I use
http://www3.towerhobbies.com/cgi-bin...&I=LXD712&P=ML
Old 02-16-2009, 11:20 PM
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Default RE: Proper prop balancing

Personaly i never sand the props, It's not really a good idea.I like dannys3 suggestion.You can buy Rust-Oleum clear Lacquer,that works really good, Just spray some on the back of the light side till it ballance's out and go from there.
Old 02-17-2009, 09:16 AM
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skysfallin
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Default RE: Proper prop balancing

I like the clear spray idea on the light side of the prop. I wish there was a way to check concentricity of the hub area or is that a mute point because its so close to the center line. Thanks for the ideas.
Old 02-17-2009, 10:47 AM
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w8ye
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Default RE: Proper prop balancing

The balancer from the Windsor prop company (MAS) sells a balancing system whereby you redrill the center hole in the hub of the prop on a new center to create a balanced prop

http://masterairscrew.com/propellerbalancesystems.aspx
Old 02-17-2009, 11:08 AM
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Default RE: Proper prop balancing

Has anyone used the Sig Manufactureing aircraft center of gravity/plane balancer/prop balancer combo tool? I need both and this would seem to kill two birds with one stone.

Bill
Old 02-18-2009, 09:55 AM
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skysfallin
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Default RE: Proper prop balancing

The sig balancer works great and is worth the money, nicely made. Does anyone have a phone number for Master Air Screw? I cant believe there web site has no information on how to contact them. I did notice the owner just died so Im wondering if they are still going to operate.
Old 02-18-2009, 12:45 PM
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Default RE: Proper prop balancing

Master Airscrew • Windsor Propeller Company, Inc.
phone (916)631-8385 • email: [email protected]

— Mailing Address —
Master Airscrew (MAS)
MASTER AIRSCREW/WINDSOR PROPELLER
PO BOX 250
RANCHO CORDOVA, CA 95741

— Additional Contact Information —
PHONE: 916-631-8385
WORLD WIDE WEB: http://www.masterairscrew.com/
Old 02-18-2009, 12:57 PM
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Default RE: Proper prop balancing

Does it happen with any propeller?

I have seen some propellers not having the hole and the plane of rotation perfectly perpendicular, which creates strong vibrations, regardless good balance.

Also check for a slightly bent shaft of the engine.
Old 02-18-2009, 08:23 PM
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Default RE: Proper prop balancing


ORIGINAL: skysfallin

The sig balancer works great and is worth the money, nicely made. Does anyone have a phone number for Master Air Screw? I cant believe there web site has no information on how to contact them. I did notice the owner just died so Im wondering if they are still going to operate.

Thanks for the feedback on the Sig balancer, sky, I'm glad I waited to buy.

Bill
Old 02-19-2009, 02:15 AM
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rambler53
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Default RE: Proper prop balancing

I just had a big debate with a local guy on this subject (non-RCU, non-PC in fact). He's got 26 years of RC experience, steady weekend flier, warm FL sun, year round so that's 52 years relative flying time for the northern modelers, in general.
He said he never once balanced a prop, and never experienced vibration, but was convinced his spinner was his problem tonight. I brought over my balancer and he said it's just a gimmick, and refused to let me assist, since I'm only back in the hobby 16 years, naturally he feels I can't give him any help. Remember, he doesn't even know what a forum is. 5 years reading on a forum is 26 years without!

I was searching for a thread to print out for him so he's aware it's not good to bury your head in the sand.
Funny thing is, the new moderator inspired trainer/beginner site discourages beginners to make prop balancing a concern, yet another says it's very important. [sm=spinnyeyes.gif]

Quote:

The next thing to consider is prop balancing. We both are in complete agreement on this - Don't worry about it.

We're not saying that you shouldn't balance your props, we're just saying that it is not a MUST DO item before you can fly your plane. Prop balancing will become very important if and when you ever start to fly planes with very large props (Over 16") or run extreme speed engines. But right off the shelf, most molded props are balanced closely enough for a trainer.


http://www.gettingairborne.com/engines.html

This conflicts with statements on this web page;

http://www.hooked-on-rc-airplanes.co...pellers.html#4

Quote:

Balancing the model airplane propeller is very import for several reasons. The most important reason is that the violent forces from an unbalanced propeller will destroy your engine very quickly! An unbalanced prop could also cause excessive foaming in the fuel tank in addition to damaging the radio equipment.


It is good practice to balance all of your props before taking them to the field. This way you don't have to mess with balancing the propeller when changing a prop at the airfield. It is always a good idea to remove any sharp edges from the propeller before balancing it.

Propeller Balancer

Many prop balancer tools are available. Top Flights magnetic balancer is the most accurate because the magnets eliminate friction in order to balance the prop more precisely.


Another statement for discussion:

The standard way to balance the propeller is to lightly sand the heavy side. It's not really important whether you sand the front or the back. But do not remove or sand the tip of the propeller because this will cause the propeller to be dynamically unbalanced even though it may be statically balanced.


Long live the hobby, and divorce lawyers.
Old 02-19-2009, 02:30 AM
  #15  
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Default RE: Proper prop balancing


ORIGINAL: nitro-pilot

I just had a big debate with a local guy on this subject (non-RCU, non-PC in fact). He's got 26 years of RC experience, steady weekend flier, warm FL sun, year round so that's 52 years relative flying time for the northern modelers, in general.
He said he never once balanced a prop, and never experienced vibration, but was convinced his spinner was his problem tonight. I brought over my balancer and he said it's just a gimmick, and refused to let me assist, since I'm only back in the hobby 16 years, naturally he feels I can't give him any help. Remember, he doesn't even know what a forum is. 5 years reading on a forum is 26 years without!

I was searching for a thread to print out for him so he's aware it's not good to bury your head in the sand.
Funny thing is, the new moderator inspired trainer/beginner site discourages beginners to make prop balancing a concern, yet another says it's very important. [sm=spinnyeyes.gif]

Quote:

The next thing to consider is prop balancing. We both are in complete agreement on this - Don't worry about it.

We're not saying that you shouldn't balance your props, we're just saying that it is not a MUST DO item before you can fly your plane. Prop balancing will become very important if and when you ever start to fly planes with very large props (Over 16") or run extreme speed engines. But right off the shelf, most molded props are balanced closely enough for a trainer.


http://www.gettingairborne.com/engines.html

This conflicts with statements on this web page;

http://www.hooked-on-rc-airplanes.co...pellers.html#4

Quote:

Balancing the model airplane propeller is very import for several reasons. The most important reason is that the violent forces from an unbalanced propeller will destroy your engine very quickly! An unbalanced prop could also cause excessive foaming in the fuel tank in addition to damaging the radio equipment.


It is good practice to balance all of your props before taking them to the field. This way you don't have to mess with balancing the propeller when changing a prop at the airfield. It is always a good idea to remove any sharp edges from the propeller before balancing it.

Propeller Balancer

Many prop balancer tools are available. Top Flights magnetic balancer is the most accurate because the magnets eliminate friction in order to balance the prop more precisely.


Another statement for discussion:

I'll bet you can dig up a pretty convincing piece on the internet that might help convice him otherwise. Spin anything at 10,000 R.P.M. and common sense should kick in. Does he balance the tires/wheels on his automobile? Maybe that's a-lot of hoo haa to him also.

Bill

The standard way to balance the propeller is to lightly sand the heavy side. It's not really important whether you sand the front or the back. But do not remove or sand the tip of the propeller because this will cause the propeller to be dynamically unbalanced even though it may be statically balanced.


Long live the hobby, and divorce lawyers.
Old 02-19-2009, 08:54 AM
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Default RE: Proper prop balancing

What a difference a day makes! Back on the vibration source...the prop AND spinner were both off. Has anyone had trouble with those Great Pains aluminum spinners that come with the ARF?

There are bubbles in the tank on this plane as well, with a balanced prop/spinner, it didn't change, so the tank is coming out next, not to hijack the thread, just thought I'd just say you told us so, and you're right. Air is getting in the tank from full the pick up fuel line (suspect) during the whole bench run. It was interesting the engine didn't seem to pulse or drop rpm (by ear).
Old 02-19-2009, 10:11 AM
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Default RE: Proper prop balancing


ORIGINAL: nitro-pilot

What a difference a day makes! Back on the vibration source...the prop AND spinner were both off. Has anyone had trouble with those Great Pains aluminum spinners that come with the ARF?

There are bubbles in the tank on this plane as well, with a balanced prop/spinner, it didn't change, so the tank is coming out next, not to hijack the thread, just thought I'd just say you told us so, and you're right. Air is getting in the tank from full the pick up fuel line (suspect) during the whole bench run. It was interesting the engine didn't seem to pulse or drop rpm (by ear).
This is a typical scenario though
Old 02-19-2009, 11:49 AM
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Default RE: Proper prop balancing


ORIGINAL: nitro-pilot

What a difference a day makes! Back on the vibration source...the prop AND spinner were both off. Has anyone had trouble with those Great Pains aluminum spinners that come with the ARF?

There are bubbles in the tank on this plane as well, with a balanced prop/spinner, it didn't change, so the tank is coming out next, not to hijack the thread, just thought I'd just say you told us so, and you're right. Air is getting in the tank from full the pick up fuel line (suspect) during the whole bench run. It was interesting the engine didn't seem to pulse or drop rpm (by ear).

Yeah, there is a fuel set up that has been spoken of here where a small secondary tank is connected to the main fuel tank and the system is presureized by the muffler. The theory follows that though the fuel supply in the main tank may foam up the fuel in the secondary tank can't because there is no air in it. Sounds brilliant to me. Come on you long timers do a better job for me.

Bill
Old 02-19-2009, 12:43 PM
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w8ye
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Default RE: Proper prop balancing

It's called a header tank
Old 02-19-2009, 02:30 PM
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Default RE: Proper prop balancing


ORIGINAL: w8ye

It's called a header tank
Thank you w8.

Bill

Old 02-19-2009, 05:54 PM
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w8ye
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Default RE: Proper prop balancing

Some times a prop is so far out of balance that a mere scraping of the the back side of the heavy blade or painting of the light blade will not suffice.

You must remove more material, perhaps from the top of the heavy blade also also.

And then you will find that you must remove material from one side of the prop hub to ever get it to balance

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