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Old Aug 02, 2010, 03:03 PM
"you'll play to live "
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Canada, QC, Montreal
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Originally Posted by dkfuji View Post
He he. . Of course. I actually installed the 180Q fuse on a 3D EP200 a while back and it did look very cool. Here is a vid of it flying in the park. The added weight did effect it flight characteristics though. The tail was not as snappy but of course I had some really cheap electronics in it and it was not flybarless.

http://www.youtube.com/watch?v=pBhDizYvKGI
nice one, Darryl! scale're always better!
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Old Aug 02, 2010, 03:17 PM
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Australia
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Originally Posted by Rafa's CB100 View Post
Thanks. Knowing this makes me feel better, actually.

There it is, we now have a baseline as to the absolute limit of time a stock battery can just hover around--6:48.

Rafa
I setup and use the alarm timer on my 2801pro TX to avoid battery outage inflight. Sometimes its hard to tell whether youve been in the air 3min or 8min so the timer alarm comes in handy. Once I know the aircrafts average air time I set the timer 30sec to 1min under.
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Old Aug 02, 2010, 06:58 PM
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Joined Jan 2009
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Has anyone tried the RX on a 450 yet? Wondering how the tail will hold with the 3axis gyro.
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Old Aug 02, 2010, 07:21 PM
Live to learn. . .
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Austin, TX
Joined Dec 2009
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I first learned of this feature a while back by hearing it on one of Manuel Campos' videos. Ironically, this is exactly what I was trying to setup when it all came crashing down--literally. Now I know to knock 30 secs to a minute off of 6:48. Living is learning!

Thanks again to everyone for all the advice so far,

Rafa


Quote:
Originally Posted by Bravo47 View Post
I setup and use the alarm timer on my 2801pro TX to avoid battery outage inflight. Sometimes its hard to tell whether youve been in the air 3min or 8min so the timer alarm comes in handy. Once I know the aircrafts average air time I set the timer 30sec to 1min under.
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Old Aug 02, 2010, 08:03 PM
RC Reviews & Tx Setup Guides
Tom Z's Avatar
United States
Joined Sep 2007
3,492 Posts
Awesome job with your 4F200 Rafa!
Your are a natural for a CP heli.
It took me many months to get to that point.
Went from Coaxial to FP to CP...

Tom
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Old Aug 02, 2010, 08:11 PM
Live to learn. . .
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Austin, TX
Joined Dec 2009
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Originally Posted by Tom Z View Post
Awesome job with your 4F200 Rafa!
Your are a natural for a CP heli.
It took me many months to get to that point.
Went from Coaxial to FP to CP...

Tom
Thanks, Tom.

I'll take a little credit, but I think it's mostly the 1s and 0s. I don't think that my 3-axis experience compares to you guys that have been doing it for a while. It's your collective experience that has driven technology to the point that it is today. I also wonder if the 'support group' of 2 years ago was as strong as the one today. Happy flyin',

Rafa
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Old Aug 03, 2010, 12:25 AM
RC Helis: My Healthy Obsession
The OC, California
Joined Feb 2007
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I have done more work on the set-up of this heli and here is what else I have found out. The servo arms are very short so that means they run out of travel way before they should. In order to achieve a full +/-12* pitch, the pitch curve needs to be at least 90% at the top and bottom. Unfortunately, when the collective reaches the top (or bottom) the servos bind up and cause a nasty interaction. At max pitch, if you give full Ail it causes the swash to interact and lean backwards. Also, giving forward/back cyclic at that position results in very little swash movement. Using the stock arms the best I could get was +/-9* without the interaction. Not quite enough for action packed flight nor any mild to serious 3D. I am going to try to work on a solution.
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Old Aug 03, 2010, 02:28 AM
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Canada, ON, Toronto
Joined Feb 2010
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Quote:
Originally Posted by dkfuji View Post
I have done more work on the set-up of this heli and here is what else I have found out. The servo arms are very short so that means they run out of travel way before they should. In order to achieve a full +/-12* pitch, the pitch curve needs to be at least 90% at the top and bottom. Unfortunately, when the collective reaches the top (or bottom) the servos bind up and cause a nasty interaction. At max pitch, if you give full Ail it causes the swash to interact and lean backwards. Also, giving forward/back cyclic at that position results in very little swash movement. Using the stock arms the best I could get was +/-9* without the interaction. Not quite enough for action packed flight nor any mild to serious 3D. I am going to try to work on a solution.
Thought +-9* was normal for max-min pitch on multi-blade heads? Are you finding this is the case with your 2 blade setup?
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Old Aug 03, 2010, 02:42 AM
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Originally Posted by erdnuckel2 View Post
Would like to second XViper, I admire your skills dk, but I don't really understand the motivation ... the one thing that made this particular bird "different" and tempting was the fact that it had a 3-blade head ... well, at least for me. So modding it into a 2blade shows mad building skills, but takes away the one thing that made that heli special ...

... like I said, just my very personal 2Cents. (apart from the fact that I should not and probably nevertheless will not buy this bird, for me temptation is based solely on the 3 blade concept ...)

For me it would definitely stay the way it is for more than just one reason ...

There are other advantages to the extra blade(s). One that I think is most relevant for smaller helis is the 3rd blade helps to dampen vibration (where a 2 blade head will actually amplify it). The blade anngle along with progression help to counter slight off balances in the head... but also because the blades are now closer together in the flight path the extra blades has less parasitic drag (because it is in the path of the blade a head of it) this means better blade tip performance...

and because there is more lift from 3 blades rather than 2 you don't need as much pitch (+- 8-9* rather than +-10-12*) to create the same lift ( nor as much headspeed - but maybe a little more torque) -which reduces induced drag (the casue of engine bogging).

And lastly you'll have quicker response from cyclic input because there is less distance between the blades.... on a 2 bladed head there is 180* travel around the swash before the blade gathers the cyclic input, on a three bladed head there is 120* travel, on four blades there is 90* travel etc.

So multi bladed heads provide better performance with a smaller rotor diameter, slower headspeeds and with less induced drag applied on the head (smoother control because HS is more consistent through the pitch curve).
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Old Aug 03, 2010, 04:22 AM
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Originally Posted by JossyRC View Post
So multi bladed heads provide better performance with a smaller rotor diameter, slower headspeeds and with less induced drag applied on the head (smoother control because HS is more consistent through the pitch curve).
I was under the impression that these gains came at a cost of reduced overall efficiency (ie thrust/Watt) can anyone confirm this?

I really like the look of this Heli, what are peoples thoughts on this as a first CP? I have a half 4#6s half v120D01 and once I'm able to fly circuits etc. I want to move to CP.
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Old Aug 03, 2010, 06:50 AM
Live to learn. . .
Rafa's CB100's Avatar
Austin, TX
Joined Dec 2009
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Originally Posted by desertstalker View Post
I was under the impression that these gains came at a cost of reduced overall efficiency (ie thrust/Watt) can anyone confirm this?

I really like the look of this Heli, what are peoples thoughts on this as a first CP? I have a half 4#6s half v120D01 and once I'm able to fly circuits etc. I want to move to CP.
Hi desertstalker,

As a CP newbie, and this as my first CP heli, I'd say that this has been a good heli for me. I was trying to decide (with some help from dkfuji) between this and a V120D02, and ended up going with this for several reasons. I like the smallness of my CB100 because I can fly indoors, but I don't see the advantage of a super-small CP heli for me, given my limited indoor and backyard space. I've heard that in CP, bigger is better, for various reasons. I also figured that the larger heli would be easier to work on.

Although there are not that many of these out there yet, some of the opinions you seek might be found in the last few pages of this thread, as some more experienced pilots than me have been commenting on my first few days of CP with this heli.

I'd say jump in, the water's fine.

Rafa
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Old Aug 03, 2010, 08:12 AM
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Balr14's Avatar
Germantown, WI.
Joined Oct 2007
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Quote:
Originally Posted by JossyRC View Post
There are other advantages to the extra blade(s). One that I think is most relevant for smaller helis is the 3rd blade helps to dampen vibration (where a 2 blade head will actually amplify it). The blade anngle along with progression help to counter slight off balances in the head... but also because the blades are now closer together in the flight path the extra blades has less parasitic drag (because it is in the path of the blade a head of it) this means better blade tip performance...

and because there is more lift from 3 blades rather than 2 you don't need as much pitch (+- 8-9* rather than +-10-12*) to create the same lift ( nor as much headspeed - but maybe a little more torque) -which reduces induced drag (the casue of engine bogging).

And lastly you'll have quicker response from cyclic input because there is less distance between the blades.... on a 2 bladed head there is 180* travel around the swash before the blade gathers the cyclic input, on a three bladed head there is 120* travel, on four blades there is 90* travel etc.

So multi bladed heads provide better performance with a smaller rotor diameter, slower headspeeds and with less induced drag applied on the head (smoother control because HS is more consistent through the pitch curve).
An excellent write-up.
However, it should be noted there is some decrease in efficiency and the increased torque means it will be more resistant to direction changes. This are why you don't see multi-blade heads used for 3D.
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Old Aug 03, 2010, 08:36 AM
JossyRC dot com
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Canada, ON, Toronto
Joined Feb 2010
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Quote:
Originally Posted by desertstalker View Post
I was under the impression that these gains came at a cost of reduced overall efficiency (ie thrust/Watt) can anyone confirm this?

I really like the look of this Heli, what are peoples thoughts on this as a first CP? I have a half 4#6s half v120D01 and once I'm able to fly circuits etc. I want to move to CP.
Need more torque to throw the weight of the extra blade.
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Old Aug 03, 2010, 08:46 AM
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Canada, QC, Montreal
Joined Sep 2009
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some references:
Converting to FL a small heli like a 250 or 450 there is a little squirrely. There 's really no difference except you are now flybarless. Meaning you won't realize what the flybar does until you actually remove it. Now comes the fun part. You need to set up the phasing, blades...perfectly and this is very critical on a multibladed head. Some scale guys fly with stabilization ie: Vbar, Skookum... and some don't. But the rule of thumb though is you should set the rig up to fly it without first, to get it's best performance.
And, a 3-blade system is inherently balanced - a 2-bladed system can never, truly, be balanced. So, lower vibration.
Also,you can use shorter blades and a slower rotor RPM but still obtain the same lift.
my2cents
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Old Aug 03, 2010, 09:22 AM
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Canada, QC, Montreal
Joined Sep 2009
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more 4F200 fuselage pics.....
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Last edited by Alwayscrash; Aug 03, 2010 at 02:04 PM. Reason: add pics
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