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Old Oct 11, 2010, 01:23 AM
RC Helis: My Healthy Obsession
The OC, California
Joined Feb 2007
3,159 Posts
Quote:
Originally Posted by GIT RITE View Post
Another quick question, How do you balance the blades on this heli, make them all of there weights the same?
You had to change the belt on the CF frame heli? There was nothing wrong with the old one. What happened? Anyway, to properly balance the blades you have to mark the COG on each blade and add tape to one end or the other until all of the blades have the same COG location (in the middle of the blades). Then take the heaviest of the three as reference and equalize the weights. Then you will ultimately have to spin it up on the bench and feel for any vibration. If there is one, you will have to add tape one blade at a time until you find what combination of tape amount and blade makes the heli run smooth. Unfortunately, in the case of 3 blades, the possible combos are to third power. It is trial and error at that point. Of course all of the above is done after you do the same to the tail blades first. That is why it takes me hours to set this heli up properly. Hope this helps bud. LMK.

Darryl
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Old Oct 19, 2010, 08:40 PM
"you'll play to live "
Alwayscrash's Avatar
Canada, QC, Montreal
Joined Sep 2009
1,732 Posts
warning !!!!check before fly for....sparks

Today while flying about 10 feet high heli suddenly get full throtle and bank right then roll over , pass through my hair within an inch and sink into ground like a rock. Result is shown on pics . I've changed new parts and thoroughly check everything before going back in air and found problem: without main /tail blades, at near mid throtle , some sparks begin to generate between belt drive and tailboom (like car spark plugs!) and immediatly RX led is blinking and lost control to Esc, resulting servos are out of control while heli's at full throtle....CRASH! that's why she sank on green grass and continue to strike main blades until stopped......due to battery wire is cut off,LOL!
I've done almost 20 flights and this is the 21Th flight with bad experience.Silicone spray will be the next solution with all belt drive helis!
So Guys, before assuming of bad RX or bad ESC, think about static spark, it's deadly dangerous.
AC
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Old Oct 19, 2010, 10:06 PM
Live to learn. . .
Rafa's CB100's Avatar
Austin, TX
Joined Dec 2009
1,489 Posts
Hi AC,

What a bummer. I'm glad you found the culprit. I can't help but wonder what changed between your 20th and 21st flights. Did the ground wire solve the problem?

Anybody else been flying this thing lately? Seems like the thread got slow quick.

I haven't wanted to say anything publicly, but for some reason (the heli gods are smiling at me, for now), I've flown 24 packs now with no incident --not to say there haven't been some near-misses!(45 packs total) I can't believe I just said that. You don't know how nervous my next flight is going to be!

Maybe by coincidence, but this good run also started right when I installed some wooden blades. I've also got some plastic blades 'on deck' to try next.

I've been limiting my flying time to 4 minutes, which leaves the batteries right at 3.8V/cell. I've got 3 batteries and 2 stock chargers now, and the ability to fly that third pack, after having warmed up a bit, really goes a long way.

I can hover pretty well in everything but nose-in, but I can also kinda fly towards myself sometimes. I've started doing circuits (that's like a figure 8, right?), but haven't quite gotten to where I want to bank it much just yet.

What fun. I'll whip out my anti-static spray for tomorrow. Thanks for the tip, AC!

Rafa


Quote:
Originally Posted by Alwayscrash View Post
Today while flying about 10 feet high heli suddenly get full throtle and bank right then roll over , pass through my hair within an inch and sink into ground like a rock. Result is shown on pics . I've changed new parts and thoroughly check everything before going back in air and found problem: without main /tail blades, at near mid throtle , some sparks begin to generate between belt drive and tailboom (like car spark plugs!) and immediatly RX led is blinking and lost control to Esc, resulting servos are out of control while heli's at full throtle....CRASH! that's why she sank on green grass and continue to strike main blades until stopped......due to battery wire is cut off,LOL!
I've done almost 20 flights and this is the 21Th flight with bad experience.Silicone spray will be the next solution with all belt drive helis!
So Guys, before assuming of bad RX or bad ESC, think about static spark, it's deadly dangerous.
AC
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Old Oct 19, 2010, 10:15 PM
Registered User
los angeles,ca
Joined May 2010
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I remember reading about static electricity. That it was dangerous and could cause problems. There was a story I think in this months RCHeli about that.
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Old Oct 19, 2010, 11:09 PM
"you'll play to live "
Alwayscrash's Avatar
Canada, QC, Montreal
Joined Sep 2009
1,732 Posts
well, i think the reason why there's static spikes may be due to atmosphere is changing (when i flew my heli, there are dark clouds and mild wind,should discharge static electricity into the air),problems that can cause "brown outs" and a reboot of the receiver with a crash as the consequence.However, spraying some silicone on preflight is a matter to prevent any crash.I'm looking for a CF tail boom replacement.
AC
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Old Oct 20, 2010, 07:23 AM
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Australia, VIC, Melbourne
Joined Feb 2010
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Quote:
Originally Posted by Alwayscrash View Post
.I'm looking for a CF tail boom replacement.
AC
Stock tube is alu right? So whats CF supposed to do as far as static goes? CF is not as conductive as alu but it's still pretty good, especially along the length of the fibres... if you want to avoid the issue wrap some thin wire around a screw or the tail boom that connects to one of the motor mount screws, should ensure there is no buildup.
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Old Oct 20, 2010, 12:10 PM
Marty
mrschultz02's Avatar
USA, PA, Media
Joined Aug 2008
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Quote:
Originally Posted by Alwayscrash View Post
Today while flying about 10 feet high heli suddenly get full throtle and bank right then roll over , pass through my hair within an inch and sink into ground like a rock. Result is shown on pics . I've changed new parts and thoroughly check everything before going back in air and found problem: without main /tail blades, at near mid throtle , some sparks begin to generate between belt drive and tailboom (like car spark plugs!) and immediatly RX led is blinking and lost control to Esc, resulting servos are out of control while heli's at full throtle
That makes sense, if the boom support is non-conductive what you have is basically a Van de Graaff generator and can generate very high static charges in the right conditions. Even if the spark is no where near the RX there will be a huge radio signal from the spark, causing interference.

Look up the design of a Van de Graaff generator, you'll see going to a non-conductive tail boom would make things much worse, allowing the tail and main body to build up even higher charges.

I can't belive they didn't use conductive plastic, anywhere you have metal rubbing against plastic or rubber at high speed you have the potential to generate static charges, if the metal parts are insulated from each other eventually you'll get a spark.
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Old Oct 20, 2010, 12:49 PM
Hong Kong
Joined Jan 2010
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Can someone tell me how difficult it is to track the blades?
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Old Oct 20, 2010, 06:35 PM
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rew-7's Avatar
UK, Leeds.
Joined Mar 2009
398 Posts
Quote:
Originally Posted by desertstalker View Post
if you want to avoid the issue wrap some thin wire around a screw or the tail boom that connects to one of the motor mount screws, should ensure there is no buildup.
What about linking tail boom screw to the neg pin of the un-used servo plug position on the Rx-would this work?
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Old Oct 20, 2010, 08:01 PM
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Australia
Joined Jun 2010
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Quote:
Originally Posted by zadaw View Post
Can someone tell me how difficult it is to track the blades?
I didnt find it that hard to track. All I did was first check the blade balance was correct. Then initialise the heli with the RX dip switch set to "ADJ" and the motor disconnected. Fit your pitch gauge and check each blade pitch when over the boom of the heli and adjust until they are all equal. This will get them very close. Then check again either in the air or locked down, which ever your comfortable with. Fit tracking tape to two of the blades so you can tell which blade is high/low. Only very minor adjustment will be needed if any if you set them up correctly with the pitch gauge. Once tracked you may have to check/adjust your pitch curve again.

Mick

ps- Dont forget to reset the dip switch to "WK" before any flight tests or the heli will tip over.
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Old Oct 20, 2010, 11:13 PM
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Australia, VIC, Melbourne
Joined Feb 2010
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Quote:
Originally Posted by rew-7 View Post
What about linking tail boom screw to the neg pin of the un-used servo plug position on the Rx-would this work?
It would, but the housing of the motor should be connected to the negative so any screw with a metal connection to the motor should work. The energy involved is tiny so any conductive path (even with high resistance) would work.
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Old Oct 21, 2010, 12:13 PM
Marty
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USA, PA, Media
Joined Aug 2008
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Quote:
Originally Posted by rew-7 View Post
What about linking tail boom screw to the neg pin of the un-used servo plug position on the Rx-would this work?
Bad idea, you'd be setting up a situation where you could damage the RX. Static electricity is bad for most computer chips.

On a brushless motor there is no connection between the windings and the case, it's the first thing you check after winding one, so the case should not be connected to the battery.

Don't think of the negative terminal on the batt as ground, there is no ground when the heli is in the air, the battery could build up a static charge just like any other part of the heli.

Static charges build up when moving parts (dissimilar materials rubbing) are insulated from each other, so to stop it you just need a conductor between all those parts.
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Old Oct 21, 2010, 06:10 PM
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jyzoom's Avatar
Singapore (Asia)
Joined Oct 2004
415 Posts
main shaft diameter

what is the main shaft diameter for 4F200 ?
Looking for a better swash follower to do mechanical phase adjustment.
Any idea welcome.
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Old Oct 21, 2010, 06:15 PM
Live to learn. . .
Rafa's CB100's Avatar
Austin, TX
Joined Dec 2009
1,489 Posts
Main shaft is 4.0mm diameter, tail shaft is 2.0mm.

Rafa
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Old Oct 21, 2010, 07:32 PM
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jyzoom's Avatar
Singapore (Asia)
Joined Oct 2004
415 Posts
Quote:
Originally Posted by Rafa's CB100 View Post
Main shaft is 4.0mm diameter, tail shaft is 2.0mm.

Rafa
Rafa...tks. This make it very hard to find a good swash follower to have a proper mechanical phasing adjustment.

Jonathan
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