Propeller Installation Question
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Propeller Installation Question
I have a question about installing a prop. on an OS engine (0.55AX). The engine is installed on an airboat so I'm not very familiar with the best way to address this issue. I figured the rc plane guys would be the best experts. I'm installing an APC prop. with a tru-turn aluminum spinner. I can't get the adapter nut to be tight enough so that the prop. doesn't spin on it's own while the motor shaft remains stationary. I believe the nut is bottoming out on the motor shaft and that's why I can't get the prop to stop moving. Does anyone have any suggestions on what I could use as a safe spacer? Thanks
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RE: Propeller Installation Question
do have the thrust washer? It should be spinner back plate, prop, thrust washer. then nut...the thrust washer is about the size of the prop hub in diameter
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RE: Propeller Installation Question
Yes, I have the engine hub with the knurled face against the spinner back plate, followed by the prop, and finally the washer with the nut fitting into it's center. The propeller that is have an an APC 10x6 and imprinted on the packaging is that it's for 50-60 2 cycle engines. It does have a narrower hub than the master airscrew 3 blade prop. that I also have on hand.
#6
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RE: Propeller Installation Question
The APC 10-6 C-2 is almost 1/16 th narrower than the APC 11 inch C-2 hubs. That prop is to light in diameter and or pitch.
If you really want to run that size then your options are to use an additional washer behind the spinner with this presenting the possibility of slippage problems or to run an eleven inch APC cut down to that diameter.
An ideal prop for that engine is an eleven inch and either seven or eight inch pitch (yup eight inch pitch).
John
If you really want to run that size then your options are to use an additional washer behind the spinner with this presenting the possibility of slippage problems or to run an eleven inch APC cut down to that diameter.
An ideal prop for that engine is an eleven inch and either seven or eight inch pitch (yup eight inch pitch).
John
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RE: Propeller Installation Question
Thanks for the feedback. Not sure what's the best prop. option, so I have either 10 or 11" diameters with different pitches and also numbers of blades. Have done some reading and it seems like everyone would have their own opinion as to what prop works best in their situation with an engine this size. Figured I would just start plaing around, but came across this prop. slippage issue as soon as I got started. I was thinking another washer might work, but wanted some other input before I started experimenting.
#9
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RE: Propeller Installation Question
ORIGINAL: albietz
Have done some reading and it seems like everyone would have their own opinion as to what prop works best in their situation with an engine this size.
Have done some reading and it seems like everyone would have their own opinion as to what prop works best in their situation with an engine this size.
Yup thats right but try reading the manual for that engine (OS has an opinion too) you might just be surprised.
John
#14
RE: Propeller Installation Question
I just looked at the OS page and the picture of the 55AX. I do not see how your nut would not go down all the way. The picture shows the nut to within 1/8" if the thrust washer with no prop at all.
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RE: Propeller Installation Question
I would guess it is the spinner adapter nut that is bottoming out. Maybe a regular nut and then the spinner nut would work, or the "long" version of the Tru-Turn nut?
Jim
Jim
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RE: Propeller Installation Question
Hey Al what i do is take my dremel put a carbide cutting wheel on it trim 1/4 inch off offof the shaft , problem solved.Not all guys will agree but I do it all the time.
#18
RE: Propeller Installation Question
ORIGINAL: JohnBuckner
Yup thats right but try reading the manual for that engine (OS has an opinion too) you might just be surprised.
John
ORIGINAL: albietz
Have done some reading and it seems like everyone would have their own opinion as to what prop works best in their situation with an engine this size.
Have done some reading and it seems like everyone would have their own opinion as to what prop works best in their situation with an engine this size.
Yup thats right but try reading the manual for that engine (OS has an opinion too) you might just be surprised.
John
#19
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RE: Propeller Installation Question
When we talk about different prop sizes for planes we are working within the engines rpm range too. By changing lengths and pitch it effects how well the engine pulls the plane. The manufacture of the engines gives us a starting point of sizes then we test different pitches and lengths to decide what prop works best for the plane/engine combo. Going too small takes the engine over it's working rpm range, too big and it lugs the engine down too much. This is what you will see when plane guys are talking about prop sizes. A 10 inch prop with the small pitch on a .55 engine could over rev it and cause problems. Running more blades like you are can compensate for a bigger prop. Check to see what rpms your engine is running just to be safe.
#20
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RE: Propeller Installation Question
One important point here is to undersatand that the manufactuers specs list HP at a certain RPM. For the most part, this RPM is not a typical nor a nominal RPM for that engine. Smaller engines will operate at higher RPMs than larger engines.
Noise does not equal power.
Having a prop that allows a high level or RPM, although it may reach the theoritical nominal for that engine (what the manufacturer states, in other words) is usualally not a practical operating RPM for that, or any engine.
A .55, for instance may say 2.2 HP at 15000 RPM (this is not what they say, but is just an example) a practical max RPM for that engine may be 11,000 RPM. So, select a prop that will give you the best performance at that RPM.
This takes trial and error and a little time to organize the stats for your particular engine and then select the prop to work with it.
CGr.
Noise does not equal power.
Having a prop that allows a high level or RPM, although it may reach the theoritical nominal for that engine (what the manufacturer states, in other words) is usualally not a practical operating RPM for that, or any engine.
A .55, for instance may say 2.2 HP at 15000 RPM (this is not what they say, but is just an example) a practical max RPM for that engine may be 11,000 RPM. So, select a prop that will give you the best performance at that RPM.
This takes trial and error and a little time to organize the stats for your particular engine and then select the prop to work with it.
CGr.
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RE: Propeller Installation Question
He may be OK with the 55AX and a 10X6 4 blade. It will not see over 14k static (calculated) and the engine will never fully unload on the airboat (it'll blow over first if it's a traditional Everglades design). The prop will most likely break if it contacts solid water at speed.
A better choice is the 3 blade Master Airscrew 10x7. The 55 with stock muffler and baffle was 11,700 (tested) and with a "tuned muffler" it jumped to 14,000 backed off 300 rpm rich on 15% fuel. The wide blades of the M.S. should offer a lot of punch to get the boat on top of the water quickly. They are more forgiving for impact than APC.
A better choice is the 3 blade Master Airscrew 10x7. The 55 with stock muffler and baffle was 11,700 (tested) and with a "tuned muffler" it jumped to 14,000 backed off 300 rpm rich on 15% fuel. The wide blades of the M.S. should offer a lot of punch to get the boat on top of the water quickly. They are more forgiving for impact than APC.