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WHAT IS BEST FOR MY TRAINER???

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WHAT IS BEST FOR MY TRAINER???

Old 03-03-2008, 11:57 PM
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shd3920
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Default WHAT IS BEST FOR MY TRAINER???

The following questions are for my Kadet Mark II with a GMS2000 .32 for power:

1] What nitro percentage (10% or 15% mixture) is best for this trainer/engine combo? What oil content is best?
2) What glow plug is best?
3) What break-in size propellor is best and how long do I need this propellor before I can switch to a larger size?
4) After the break-in what size propellor would be best?

If it matters, I will be flying in a grass field with very short (if any) grass.

I am going to purchase them from Towerhobbies so if you can suggest something from them it would be great.

I am starting to get things organized to FINALLY fly this year and I am excited about it, the house situation I had (foreclosure) seems to have finally been solved so I can get back into the flying I was supposed to start last year.
Old 03-04-2008, 05:41 AM
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Mr67Stang
 
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Default RE: WHAT IS BEST FOR MY TRAINER???

Here is a link to that engines owners manual which answers most of your questions.
http://www.toprc.co.nz/GMS%202000%20ENGINES%20OWNER'S%20MANUAL.htm

A quote from the manual:
BREAK-IN
Your GMS engine has a closely fit piston which requires only 15 to 30 minutes running before it will idle reliably. No special fuel or propeller is necessary, but it is recommended you use the fuel and propeller you intend to use in your plane. Take care that the engine is not run overlean (leaned in to the point that it loses power).
The recomended prop range for this engine is 8x6 to 9x6 and me being who I am would even try a 10x5 based on those numbers just to try to get a little more pull with less top speed on a trainer. If it loads your engine to much (not getting full RPM out of it or slow spin up) you could try a 9x5 or a 10x4. This manual also says something about not using nylon props due to excessive vibration... I think that is a load of horse stuff but it's your engine. As far as fuel is concerned I like 15% nitro and 18% Synthetic oil with a splash of Sig castor oil for good measure (roughly raising the oil content to 20%)... That is me though.

Another quote:
GLOW PLUGS
This series of engines all use the long thread glow plug. We recommend medium heat range plus.
As far as glow plug I like OS #8's.

Another quote from the manual:
FUEL TO USE
Model airplane fuels are a mixture of methanol, oil, and various additives to improve ignition, add power, and cut down carbon deposits. It is important to use fuel with a castor oil and/or synthetic lubricants, otherwise, your engine life will be drastically reduced. Nitro is another fuel ingredient that is often used. Its function is to "advance the spark". To determine if you need any, or more nitro, start your engine, open the throttle wide open and set your high speed needle for maximum power, then back it out slightly. Do all this with your booster battery connected. Now remove your booster leads - if your motor slows down, more nitro is indicated. Conversely, if your motor speeds up, there is probably too much nitro. We recommend high quality commercial fuel with 10~15% of nitro.
There description of what indicates a need for more or less nitro can also be and more likely be an indication that your tuning is off or your glow plug is going bad.
Old 03-04-2008, 10:15 AM
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shd3920
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Default RE: WHAT IS BEST FOR MY TRAINER???

As quoted by Mr67Stang:
". . . This manual also says something about not using nylon props due to excessive vibration... I think that is a load of horse stuff but it's your engine."

As quoted in engine's manual (link given to me above):
". . . We urge that you do not use nylon propellers because their flexible nature causes more vibration."

Any other opinions on this?


Thank you MR67Stang for the info
Old 03-04-2008, 11:01 AM
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Missileman
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Default RE: WHAT IS BEST FOR MY TRAINER???


ORIGINAL: shd3920

As quoted by Mr67Stang:
". . . This manual also says something about not using nylon props due to excessive vibration... I think that is a load of horse stuff but it's your engine."

As quoted in engine's manual (link given to me above):
". . . We urge that you do not use nylon propellers because their flexible nature causes more vibration."

Any other opinions on this?


Thank you MR67Stang for the info
I agree, that is total BS.
Old 03-04-2008, 11:09 AM
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mclina
 
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Default RE: WHAT IS BEST FOR MY TRAINER???

If you haven't already purchased them, I'm curious why you chose the GMS .32 . I realize it's right in the middle of the range for recommended engines, but the GMS .40 is the exact same price. I think it is pretty typical that .40 size engines are cheaper than .32 size engines, simply because they sell more of them. There shouldn't be a big difference in either weight or fuel consumption, and a little extra power never hurts. Plus, there will be more airframes that you can transfer a .40 size engine to than a .32.

Good luck with your Kadet. It's a great choice.




****Edit - I stand corrected. According to the specs, the GMS .40 weighs 6 ounces more than the .32, that is significant. And if you can believe their HP numbers, even for comparison, they put out almost the same hp.

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