8/3 vs 3/2 mm HB Cutdown Stock Blades - RC Groups
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Nov 12, 2003, 04:17 PM

8/3 vs 3/2 mm HB Cutdown Stock Blades

Totally stock setup with 370 motor.
Some say cutdown stock blades 8mm at root, 3mm at the tip, others say 3mm a root, 2 mm at the tip. Any concensus on which is best.
As a newbie my first flight is with 3/2mm stock cutodown blades. I just break ground effect with fresh 2s lipo packand full throttle. Would the great er cutback decrease the throttle demands?
wonder what others suggest.
FYI, Devocon Plastic Weld at Wal Mart works outstansding with the stock blades for repiars. Woudl never have thought I could fix the stock tail rotor. Of course they need to be rebalanced after.
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Nov 12, 2003, 04:55 PM
"Simplify, then add lightness"
With the cut blades, you will probably want either a larger pinion, or a 3 cell LiPoly. I cut some old blades to 8mm-3mm and they worked great for the first couple minutes on a 2 cell etec 1200, but after a few minutes would not get out of ground effect. You could try twisting more pitch into your cut blades. I went back to the stock blades and just twisted them to flatten the pitch and get higher head speed.

Nov 12, 2003, 05:05 PM
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fatboywings's Avatar
So you can just break ground effect with full throttle. You will be having much more control with you higher head speed but please remember that you should cut your blades and make a head stiffener. the head stiffener will help with lift a little also.

Also remember that if you are only learning to hover that this mod is not essential. It becomes essential when you want to do FFF.

During FFF you actually use less throttle than it takes to hover. There fore you will not be at full throttle during FFF.

Nov 12, 2003, 05:24 PM
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JIMJAM's Avatar
Still having troubles but I can say that when I cut the blades, 8MM at the root to 3MM at the tip, it was a big difference in stabilty. However, I am still having problems with extremely low flight times. Could be the increased work load of the motor and batteries to produce lift. I would work out any bugs and gremlins flying stock then start trying. Throwing another variable into the mix is just something else to cloud up a solution. Just my $650.
Nov 12, 2003, 05:53 PM

Jimjam Hover Time

As a benchmark what kind of hover time are you getting just out of ground effect with your 2s lipos. THought you mentioned five minutes. ONce I get my legs under me and quit runinng into the entertainment center, I'll cross check my hover times with 2s(3/2cut baldes and rest stock) to yours and see if it helps you. On the ohter hand too much info is disinformation sometimes.
Nov 12, 2003, 06:34 PM
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JIMJAM's Avatar
Man you guys who hover indoors have my admiration. The only other heli I dared hover indoors was a Corona. If you can hover indoors while kicking up all those nasty wind currents and maintain cool only feet or sometimes inches from another order for parts, outside is boring.
Nov 15, 2003, 12:00 AM
Registered User
My brothers stock Dragonfly was having all kinds of problems flying. I cut his blades down 3mm at the root and 2mm at the tip.

Rotor speed went up and much more stable. Flight time on his stock battery was 6 minutes. I also added a headstiffener at the same time.

To cut the blades I scribed a line from the root to the tip on the under side of the blades and then used a good pair of scissors to cut on the line. I filed the trailing edge with a file to get a nice sharp edge instead of the flat edge made by the scissors.

Seems to work. I don't know if 8mm at the root is better or not. Seemed like a lot so I opted with 3mm at the root.