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Old 01-12-2017, 09:40 AM   #1 (permalink)
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Default 3 blade align 800 lowrpm

I have soon a 3 bladed main. Tail is already 3 blade for 2 years ago. What is the lowest rpm i can fly? I have 7s lipos now and rpm is 725-1300 rpm. Is there align lowrpm dudes here? How can i get more tail rpm?
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Old 01-12-2017, 04:57 PM   #2 (permalink)
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align made couple gear set for front tail gear. you can try 21t gear set. from 700n ratio will be 4.95 instead of 4.72 but probably need to slot little bitte the tail mounting
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Old 01-13-2017, 12:23 AM   #3 (permalink)
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do the math...

RPM at the end of the flight are calculated using this formula:

100% RPM = Kv of motor x 0.9 (90% motor efficiency) x Volts / Gear ratio

Gear ratio = Number of teeth on main gear / number of teeth on the pinion

I had a T700 stretched to 800 size... it was a 12S setup... but I flew it on 6S just for run and it was awesome.... needed some more pitch to hover but other than that it was OK...

gh
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Old 01-31-2017, 05:55 AM   #4 (permalink)
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Quote:
Originally Posted by darknight736 View Post
align made couple gear set for front tail gear. you can try 21t gear set. from 700n ratio will be 4.95 instead of 4.72 but probably need to slot little bitte the tail mounting
I will try this. I am making a order from our best seller. 753 rpm and tailblows like hell. With 900 ok and with 1200 solid rock almost.
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Old 02-01-2017, 12:22 AM   #5 (permalink)
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What you didn't mention was the length of the tail blades. I am running my 700 scale trainer at 1000rpm and a pair of 115's couldn't hold it under heavy pitch load so I have switched it to a triple blade tail but have not had it in the air with that tail rotor. The fastest ratio I can run on my MD7 is 4.33:1 but later on, I will be lowering the speed to 850. In a perfect world, a tail speed of between 8000 and 9000rpm, works out to be the magic range for good, hard tail response. At 3680, I will need all that those blades can give, but I might need to explore 120mm blades as I am well below the optimum range that had been suggested to me. For scale flying, the low thrust tends to simulate what the tail authority is like on a full size helicopter. Take care.

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Old 02-01-2017, 12:11 PM   #6 (permalink)
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I have halo 3x115mm. Wondering if i found some 120mm triblades. I will order the align nitro gears. 1000rpm almost rock solid. The pitch is now 13 or was it 12. With 2 blades i had 14 in pitch.
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