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AP and Scale Discussions for Scale, Multi-blade and AP applications using CSM Cyclock, Helitronix Multi-mixer, Spartan AP2000i, Firmtronix, Digimix-3.


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Old 09-17-2007, 02:59 PM   #1
Mike SVOR
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Default Another question about 4 and 5 blade rotors

I think I understand what people mean when they say the helicopter will be more 'twitchey' with a 4 or 5 blade head. I'm guessing this is because the flybar is removed. I have watched how flybar-less helicopters fly and it seems they don't return to a position once moved if that makes sence.
So here is the question.
If I put a 5 blade head on, basically flybar-less, how can I stabilize the helicopter so it acts like a heli With flybar?

Could I use 2 more gyros that control pitch and roll?
I tried to do this with the real flight simulator and don't think I got it right or it doesn't work or I don't understand the concept.

Can someone help?

Thanks!
Mike
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Old 09-18-2007, 12:03 AM   #2
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More weight in the blades. Shoot an E-mail to JMD Models.. These guys run all kinds of flybarless heads with NO mixers or gyros to help out. They add weight to the blades. I had a great conversation with those guys this past weekend about a 5-bladed setup for a Trex450 and checked out two 450 sized 5-bladed prototype heads, including one they were flying....
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Old 09-18-2007, 08:05 AM   #3
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On the larger scalers (nitro, gas and turbine) gyros are commonly used on the pitch axis, and sometimes roll axis as well. There are even electronic mixers available that will make them fly like a flybarred head. Then again, as Skiddz noted, there are many who fly them with no gyros.

I'm currently test flying a 3-blade head on one of my TRex 450s in preparation for a scale fuselage. It's twitchy, but flyable. Adding weight to the blades will help, and slowing the headspeed down helps as well.

I'm still researching the possibility of putting a 5-blade head on my Raptor/MD500, but the cost is prohibitive...
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Old 09-18-2007, 08:22 AM   #4
Mike SVOR
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thanks guys,

Do any of you know how gyros are added to a 3 post swashplate? I forgot the name of this type of swashplate, but it only has 3 points of contact and requires servo mixing. It's what comes on the preditor.

got any links to how this is done?
I'm not in a rush to do this right away or anything, but think its required knowledge and I love 5 blade rotor heads. trying to get into the technology.
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Old 09-18-2007, 08:39 AM   #5
Rodan
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It's called a 120 degree swash, and I think you will need a mixer, as you can't plug in the gyros on a single servo like you can with the tail.

Here's the one most of the scale guys are using: http://www.helitronix.com/index.html
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Old 09-18-2007, 06:26 PM   #6
Mike SVOR
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Thanks Rodan, That is just the info I was looking for.
I wish I knew more about it cause i'm really not understanding how it works with the 120 swashplate.
I guess this is going to take time.
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AP and Scale Discussions for Scale, Multi-blade and AP applications using CSM Cyclock, Helitronix Multi-mixer, Spartan AP2000i, Firmtronix, Digimix-3.

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