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What to use.... Propeller question??

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What to use.... Propeller question??

Old 09-29-2010, 01:04 PM
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CGCINC
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Default What to use.... Propeller question??



I am planning on a maiden flight of my G.P. Escapade this weekend.
This will be my first nitro flight and I'm wondering what sizeto start out with for thepropeller?

Engine is an O.S. .40LA with the baffle removed from the exhaust (small increase in rpm's)
Propeller's I have:

10x4 Wood
10x6 plastic
11x4 Wood
11x6 plastic

What is the difference, if any, between the wood and the plastic/composite props?

Old 09-29-2010, 01:17 PM
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vpresley
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Default RE: What to use.... Propeller question??

Hi

First and most important, read the instructions for your engine. They will tell you what to do, how to do it, and what propellor to use. If you dont have them, you can find them online at the OS engine website, or at the Great Planes website. No substitute for reading the instructions.

Vince
Old 09-29-2010, 01:19 PM
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MinnFlyer
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Default RE: What to use.... Propeller question??

I would go with the 10x6 nylon
Old 09-29-2010, 01:54 PM
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Augie11
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Default RE: What to use.... Propeller question??


ORIGINAL: MinnFlyer

I would go with the 10x6 nylon
Ditto on the 10x6 nylon for a start. You can change sizes to suit your flying style after that. The 11x4 might give you better vertical and/or hover potential. The other 2 are probably outside the recommended range..... as the fellow said, check the instructions.
Old 09-29-2010, 02:02 PM
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Charlie P.
 
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Default RE: What to use.... Propeller question??

10X6 Nylon. If it lands too hot for your tastesswitch to a 11X4 (or an 11X5, which you don't list).
Old 09-29-2010, 02:11 PM
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CGCINC
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Default RE: What to use.... Propeller question??

I've read the destructions....Any of these props will work with this engine.... I just needed a general starting point for my first flight. It says in the manual from 10x6 to 11x6 so the 10x4 might not work so well.

I have the11x4 installed and I would likethe first fewflights to be on the slowside. It is a wood propeller, is there any difference besides the material used tomake it?
Also,when you goup an inch in size, do you automaticallygo down on the pitch? (just wondering why youwent from the 10x6 to the 11x4 instead of the 11x6?)
Old 09-29-2010, 02:13 PM
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daven
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Default RE: What to use.... Propeller question??

Wood tends to break easier, but like you said, all of those props will run on that motor. Kinda depends on your flying style and what you like. I'd probably go for a 10x5, or 11x4 personally, but I don't mind spinning them up.
Old 09-29-2010, 02:16 PM
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Default RE: What to use.... Propeller question??

I just checked the CG and I need to add around 8-9oz. to the nose to get it level. Is that normal?
Old 09-29-2010, 02:23 PM
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Charlie P.
 
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Default RE: What to use.... Propeller question??

That's a lot, and on a low-end engine for the airframe so they wereobviousy designing for a heavier engine. But, you've gotta do what you've gotta due to balance. Do you have the battery as far forward as you can place it? Throttle servo? Anything you can do to reduce added weight usually pays off in flying characteristics.
Old 09-29-2010, 03:05 PM
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Default RE: What to use.... Propeller question??


ORIGINAL: Charlie P.

That's a lot, and on a low-end engine for the airframe so they wereobviousy designing for a heavier engine. But, you've gotta do what you've gotta due to balance. Do you have the battery as far forward as you can place it? Throttle servo? Anything you can do to reduce added weight usually pays off in flying characteristics.
Battery, yes. Throttle servo... it's where it's made to gobut I bet I could move it a couple inches forward with a little coaxing.

I used the plastic engine mount instead of my Aluminum mount so that I could move the engine as far forward as possible... The old Aluminum mount was 3/4" shorter than the plastic one. I'll go through it all one more time and make sure it's all as far forward as possible.
Old 09-29-2010, 03:46 PM
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scooterinvegas
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Default RE: What to use.... Propeller question??

Thats A LOT of weight to add to a 40LA powered plane. I would put a weighted prop nut with a 11x5 apc up front and wedge a flat 4 cell up with the fuel tank. Than will help a lot. That engine does not have much power, adding weight anywhere is going to slow it down. I replaced my 40 LA with a 46 AX, holy crap that woke up my superstar 40! Good luck.
Old 09-29-2010, 04:36 PM
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Default RE: What to use.... Propeller question??


ORIGINAL: scooterinvegas

Thats A LOT of weight to add to a 40LA powered plane. I would put a weighted prop nut with a 11x5 apc up front and wedge a flat 4 cell up with the fuel tank. Than will help a lot. That engine does not have much power, adding weight anywhere is going to slow it down. I replaced my 40 LA with a 46 AX, holy crap that woke up my superstar 40! Good luck.
I'm gonna try everything I can to move stuff around. If I have to I have to but I would like to cut the amount of added weight in half at least.
Old 09-29-2010, 10:51 PM
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Default RE: What to use.... Propeller question??

On your pitch vs. diameter question, the engine can only handle so much load before you're lugging it and it can't get into its power band. So if it runs well with a 10x6, it probably will be overloaded with an 11x6. But if you find yourself needing better vertical performance and acceleration, going to an 11x5 or 11x4 will give a similar loading. You're just making a trade off between pulling power vs. top end speed.

And now for the question no one has asked you yet. Are you planning to fly this plane without any RC piloting experience? If you've been flying electrics or park flyers, then feel free to disregard the warning, but if you're new to the hobby your first flight won't likely turn out well. Even if you do have some experience, it would be wise to get someone who's been flying nitro for a while to look your plane over and do the initial test and trim flight for you.
Old 09-30-2010, 07:00 AM
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Default RE: What to use.... Propeller question??


ORIGINAL: jester_s1

And now for the question no one has asked you yet. Are you planning to fly this plane without any RC piloting experience? If you've been flying electrics or park flyers, then feel free to disregard the warning, but if you're new to the hobby your first flight won't likely turn out well. Even if you do have some experience, it would be wise to get someone who's been flying nitro for a while to look your plane over and do the initial test and trim flight for you.
I've been flying electric trainers... Apprentice 15e and a cheapy foam Cessna from nitroplanes.
The only thing that I feel uncomfortable with is the fact that I've never flown a low wing plane besides in my Phoenix simulator..... But it's going up this weekend with me at the controls!!
Old 09-30-2010, 07:12 AM
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Default RE: What to use.... Propeller question??

Move the engine as far forward as you can. Get a longer engine mount if necessary.
Old 09-30-2010, 07:48 AM
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Default RE: What to use.... Propeller question??


ORIGINAL: gaRCfield

Move the engine as far forward as you can. Get a longer engine mount if necessary.
It's at the very end of the mount that was supplied.... never thought of a longer mount!?!?
I moved the gas tank about 1/2" forward, the Rx battery moved about 1/2" forward as well. There's just not much room to do anything else.
Old 09-30-2010, 11:34 AM
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Default RE: What to use.... Propeller question??

OK guys... Wondering if this will work for the weight situation?

I cut a piece of Balsa to fit the lowernose area and I'm thinking of drilling and glueing several round weights in in, then glueing it to the plane. (of course it will be white when I'm done)
This will help get the weight as far forward as possible... Yes/No???






Old 09-30-2010, 11:46 AM
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Default RE: What to use.... Propeller question??

That will work. On a World Models Sky Raider, my brother made a thin flat plywood plate and mounted the receiver battery under the engine. He extended the wires to reach the switch. This avoided adding any weight except for the plywood and glue.
Old 09-30-2010, 11:50 AM
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Default RE: What to use.... Propeller question??


ORIGINAL: carrellh

That will work. On a World Models Sky Raider, my brother made a thin flat plywood plate and mounted the receiver battery under the engine. He extended the wires to reach the switch. This avoided adding any weight except for the plywood and glue.
Thats an idea!! I have plenty of extension wires. Hmmmmm...... back to the planning board!
Thanks..

Will the heat mess with the battery, or the Nitro?
Old 09-30-2010, 12:22 PM
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Default RE: What to use.... Propeller question??

There was a small air gap between the engine and battery so heat was not a problem. Not sure if oil/fuel would bother it but he wrapped the pack in thin foam, then wrapped that with clear plastic tape to keep raw fuel and oil away from the batteries. I think he used a little dab of RTV silicone caulk to seal the hole where the wirewent through the firewall.
Old 09-30-2010, 05:58 PM
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Default RE: What to use.... Propeller question??

OS 40LA's love 10x6
Old 09-30-2010, 06:34 PM
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Default RE: What to use.... Propeller question??

Go with the 10-6 like most everyone uses. It turns right in the sweet spot for the LA .40.

I would use a black Master Airscrew plastic as it should be heavier than the APC and it chips less if your landings aren't too good.

Get a Harry Higly or Great Planes brass heavy hub. They add weight right out at the end of the crankshaft where it is most effective.

I don't know what your instruction manual says for CG, but reach underneath and pick your plane up by the main spar on both sides. That location is a good gestimate as to the CG.

Have you added something extra to the tail area like a different tail wheel or heavier wire? I would not think that your plane would require 9 ounces.
Old 09-30-2010, 08:42 PM
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Default RE: What to use.... Propeller question??


ORIGINAL: Ed_Moorman

Go with the 10-6 like most everyone uses. It turns right in the sweet spot for the LA .40.

I would use a black Master Airscrew plastic as it should be heavier than the APC and it chips less if your landings aren't too good.

Get a Harry Higly or Great Planes brass heavy hub. They add weight right out at the end of the crankshaft where it is most effective.

I don't know what your instruction manual says for CG, but reach underneath and pick your plane up by the main spar on both sides. That location is a good gestimate as to the CG.

Have you added something extra to the tail area like a different tail wheel or heavier wire? I would not think that your plane would require 9 ounces.
I agree, 9 ounces IS a lot! But I think it's the motor. The motor they recommend is about 6oz. heavier the my little .40LA
I haven't added anything to the plane except aswitch/charge port but that is real close to the CG area on the wing, a tad to the rear.
I bought a G.P. brass nut today which added 2.5oz's and I drilled the wood and added about 6oz's to it and the plane balances just a hair nose heavy with a full tank of fuel.
ended up buyinga few more props today as well.... The wood props were really light so I bought all Master Airscrew plastic's.
I've had this engine running with the 10x6 And the 11x6 on it and they both sound close to the same in rpm's, of course the 11x6 was put on after I removed the baffle in the muffler.
Bought a tach today so I will be able to check and get a "real" reading instead of my ear.

They say for "run in" on this motor to use an 11x5 prop. For trainer/sport flying they say 10x6~ 10x7 OR11x5~ 11x6
Old 09-30-2010, 09:45 PM
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Default RE: What to use.... Propeller question??


ORIGINAL: CGCINC

the plane balances just a hair nose heavy with a full tank of fuel
Balance with out fuel!! No fuel is close to landing weight, so you take off with the plane nose heavy, and land closer to the CG. If you bal with a full tank of fuel, the plane will become VERY tail heavy in flight.
Old 09-30-2010, 10:04 PM
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Default RE: What to use.... Propeller question??


ORIGINAL: scooterinvegas


ORIGINAL: CGCINC

the plane balances just a hair nose heavy with a full tank of fuel
Balance with out fuel!! No fuel is close to landing weight, so you take off with the plane nose heavy, and land closer to the CG. If you bal with a full tank of fuel, the plane will become VERY tail heavy in flight.
OK... makes sense. Of course I'll be adding more weight to balance if I empty the tank

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