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HomeAircraftHelicopterBergen R/C Helicopters › To design a ratio chart for our Bergens
04-02-2005 05:39 AM  13 years agoPost 1
mike lewis

rrApprentice

northeastern AZ

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Any one have a software program that would create a chart that would give us the available engines and their favored RPM ranges, in the Bergen Gasser. The available main gear tooth count and the available pinion gear tooth counts. The resulting gear ratios.
Now then lastly The lift in pounds and ounces that a given blade set will lift at different main blade RPM
Example would be Zenoah 260 PUH 12,850 rpm 8.18 final gear ratio running 810MM blades at say 1,400 will lift 17lbs. 9 oz.
I know that blades would vary quite a bit from semi to full symmetrical and from one manufacturer to another o-yes and the pitch also and the weight would vary as well. Just some kinda chart would be nice to get a starting place

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04-02-2005 06:15 AM  13 years agoPost 2
Chris Bergen

rrElite Veteran

cassopolis, MI USA

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Add in also Mike,

New engine or broken in

Oil mix and needle settings

Baro altitude and Outside air temp (OAT)

Chris D. Bergen

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04-02-2005 06:39 AM  13 years agoPost 3
mike lewis

rrApprentice

northeastern AZ

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So much to consider
There are so many variables that it would only lightly cover the mechanical type of data not so much every aspect. However each item to consider has such authority over the end result I guess that might not be so easy to construct a chart. I guess it would really have to be limited to the known items that don't change from season and regions,or in there extrems would not have an effective out come in excess of 2% of the overall preformance factor. Hope this is clear and makes scense I guess it would have to boil down to the most important issues would be considered for input. KISS?

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04-02-2005 02:52 PM  13 years agoPost 4
wolfdad

rrKey Veteran

Southern Maryland

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I would think, a chart, using "standard day (15° C and 29.92")" and manufacturer's recommended paramters for target RPM, recommended blade length, etc. would be fairly easy to come up with. The "variables" are the items that "common sense" would be the deciding factor on. I think you would have to assume a "broken-in" engine and again, manufacturer's recommended oil/gas mix, needle settings, etc. You can "chase your tail" on variables, kinda' like I did with my Hanson engine, until somebody finally said, to get into the power band on that specific engine, using the manufacturers specs, I needed to drop down to an 11T pinion.....dohhhh.

wolfdad sends....

"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105

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04-02-2005 02:58 PM  13 years agoPost 5
rafael

rrApprentice

Oaxaca, Mexico

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Something to begin with.....
Check my gallery I have a Excel file(zip) with the info for the10,11,|12,13, and 14 tooth pinion gears with the 90T main gear.

I think we can work to add all the info that is missing, fuel mix, different main gears, carb settings, etc

Click in display all(gallery) to be able to see the file, if you add something to the file please send the new file so I can update it.

hope it helps...

Rafael Castañeda
www.helicam.com.mx
www.rcoaxaca.com
www.737-700.com/simuladores/

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