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Old Sep 03, 2012, 11:07 PM
IHW Heli Division
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United States, FL, Palm Coast
Joined Mar 2012
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Originally Posted by ChopperJack View Post
I agree, 100 per cent mechanical alignment would be best in a perfect world. You know, it would be just perfect if those little servo arms would attach to the servo spline shaft perfectly at 90 degrees! Unfortunately, perfect 90 degree mechanical alignment is IMPOSSIBLE. That is why they gave us subtrim. If subtrim will allow you to achieve perfection, might as well use it. Just my 2c.

Your right. Believe me, I'm only trying to help and this is also an issue of much debate in the RC world. The reason it is impossible to get 90 degrees is because Walkera does not have a way to adjust individual servo neutral and end limits. On top of that, like you said, they don't mold the teeth inside the horns at the correct angles for 90 degrees most of the time. So the best you can come up with is using subtrim. Many people say this is fine and there is nothing wrong with it. But i'm pretty sure, not positive. I think that the Walkera instructions even say not to use subtrim? But many people i know are using it with no problems.

I prefer not to, as i said before. Your right, in a perfect world... This and that... But, don't forget your flying a Walkera, it's not like it matters all that much. Your going to crash again after all. But when i used to use subtrims, when i go inverted the heli pulls to the side or wants to tilt one way or the other but flies fine upright. It's been a while since i tried using them and have since learned a lot. So it's possible i was just setting everything wrong anyway.

What i do now, since i have replaced the servos so many times, is match up all of my servo horns until i get to 90 degrees on all. Or close enough that i don't care. Then i make mechanical adjustments from there to level my swash. Sometimes it's just a matter of switching the 3 horns that came in the package around a few times and they might actually all come out to almost 90 degrees. But if that don't work, thats why i save all my old servo horns! I just grab a hand full and start matching them up while they are powered up and set to neutral.







Like we were saying, sometimes they just don't hit 90 degrees, some are close, like the one above. Thats why you have to keep looking. Eventually you will get one that is almost right on the money like these below:
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Old Sep 04, 2012, 01:43 AM
Team WarpSquad
Japan, Tokyo
Joined Jun 2011
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I'm amazed that the horns are not all the same. It makes me wonder what the hell their mould tool company was doing when they made the servo arm moulds.

The other way to fix it is to start taking the servos apart and moving the gears until you get 90 degrees, but compared with a bit of sub-trim it seems a very long way about it - especially as you correctly say, 'until your next crash'.
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Old Sep 04, 2012, 02:02 AM
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Quote:
Originally Posted by thwaitm View Post
I'm amazed that the horns are not all the same. It makes me wonder what the hell their mould tool company was doing when they made the servo arm moulds.

The other way to fix it is to start taking the servos apart and moving the gears until you get 90 degrees, but compared with a bit of sub-trim it seems a very long way about it - especially as you correctly say, 'until your next crash'.
I know, it's really strange. I think they offset them on purpose. Because again, i swear i read in the manual somewhere about not using subtrims. But that might have been in the v450 book from wow or something too. One thing is for sure. My savox/align servo horns are always the same. One breaks, the next one goes on just like the last and no linkage adjustments are needed ever. Funny thing about quality servos. The horns break. Not the servos.. Walkera.
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Old Sep 04, 2012, 03:03 AM
Team WarpSquad
Japan, Tokyo
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Quote:
Originally Posted by IntegrityHndywrk View Post
I know, it's really strange. I think they offset them on purpose. Because again, i swear i read in the manual somewhere about not using subtrims. But that might have been in the v450 book from wow or something too. One thing is for sure. My savox/align servo horns are always the same. One breaks, the next one goes on just like the last and no linkage adjustments are needed ever. Funny thing about quality servos. The horns break. Not the servos.. Walkera.
---- The horns break. Not the servos..

Yep - this is all about materials choice.
The Savox/Futaba horns are all made of a rather more brittle plastic which is fine when load is increased 'gently and progressively' as during flight but if there is an impact load from a crash, they tend to snap and avoid transmitting the crash energy back to the gears.

Walkera servos on the other hand have really tough rubbery horns which you can bash and deform before they break. They will rip or split instead. So in a crash all that energy just gets passed straight down the horn and into the servo which then finds the weakest link and grinds it to pieces.

Servo horns are dead easy and cheap to replace. If your lucky they make the horns you need on separate moulds from the other types and you can buy bags of 10 horns all just the type you need!!
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Old Sep 04, 2012, 04:44 PM
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The larger Futaba servos with four arms have each arm labeled,1 through 4, and each arm has a slightly different orientation just so that you can 'sneak up' on the right angle by moving through arms 1 through 4, as required.

Don't think the little cheapo 9 gram one arm servos do anything like that though, as far as I know.
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Old Sep 04, 2012, 11:31 PM
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Originally Posted by tracknoob View Post
The larger Futaba servos with four arms have each arm labeled,1 through 4, and each arm has a slightly different orientation just so that you can 'sneak up' on the right angle by moving through arms 1 through 4, as required.

Don't think the little cheapo 9 gram one arm servos do anything like that though, as far as I know.
Actually, that is exactly what i suspect is going on. Like i said previously. Sometimes all you have to do is swap out the 3 horns that come in the package. Sometimes they line right up. Other times not. So it just seems like to me they use random patterns on the teeth for the spline. It could be that they are numbered too though. I have seen that somewhere else before on one of my helicopters.
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Old Sep 05, 2012, 03:35 AM
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For anyone that cares. The Walkera 09-9 MG servo from the V450D01 is a drop in replacement for the 4f200's tail servo. I would assume that the 09-8 with plastic gears will work also. I couldn't find a 4f200 tail servo for sale anywhere. So i tried all the servos i have. That one works and is a little faster i think. It probably has a lot more torque too. However, in my opinion. Metal gear servos are a poor choice for the tail. This one in particular is way too heavy. For a servo, in which i have never stripped on any of my helicopters, I just can't endorse adding all that extra weight. With my swash perfectly leveled the heli only wants to tilt back. I shortened the elevator linkage 2 turns and it was STILL pulling backwards. 3 turns.... okay, this thing is just too damn heavy because it was still trying to tilt back.
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Old Sep 05, 2012, 10:05 PM
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Just tape a quarter inside the bottom of the canopy to balance it out.
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Old Sep 05, 2012, 11:18 PM
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Originally Posted by clearprop88 View Post
Just tape a quarter inside the bottom of the canopy to balance it out.


I use those thin lead weight stickers for balancing ceiling fans.. Or bullets that have not been loaded yet. I just cut them to the weight i need. I don't really want to add weight. I plan on eventually getting a regular replacement. The 09-9 seems pretty damn heavy though. I suppose it don't matter because this heli is not capable of hard pumping 3d or anything. Just the basic flips, rolls and inverted. You might get a tick tock or 2 out of it but really.... It's a novelty act.


Speaking of which... My 200 project i mentioned i started building a while back is almost complete. Shouldn't be long now. It flies even! Just have to get the finishing touches and a few parts on order to arrive. Very excited to reveal it.
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Old Sep 05, 2012, 11:49 PM
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OK. I'm looking forward to seeing it.
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Old Sep 10, 2012, 01:24 AM
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The Unveiling of phase 1

Well. I've been holding back on releasing pictures or video of this very nice, very cool little project I've been working on. The helicopter has evolved past what i am currently releasing. But, none the less. Here is where i started:


The "4F200SD5"






A few more images can be found below. Here is the initial test hover! I was so excited!

4F200SD5 - 5 Blade rotor first test hover! (3 min 7 sec)



So i had to take it for a test flight to make sure it would fly

4F200SD5 - 5 Blade Rotor - Test flight at the park (5 min 29 sec)



Then after a little while i got some new blades for it and managed to tune the helicopter a little more. These new blades are more flexible and much more narrow. They really flew much nicer and allowed me to open up my pitch curves a lot more. Previously I had to limited at the extremes at least 10% or more due to the width and additional load of the white 200mm blades. The narrower blades made the collective stick a little bit less sensitive even with nearly full pitch range (0-100%), since less air was moving per blade now.

Excuse the dirty, scratched paint job on the canopy. This was a test flight and i didn't want to crack up my nice white one. I still am unsure which blades will be best suited for actual flight in the end. But the black blades will look nicer later... Trust me.
4f200SD5 - 5 BL Rotor - SD5 Stock blades test flight (4 min 30 sec)
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Old Sep 10, 2012, 12:49 PM
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Great work on all that experimentation! Cool stuff!

Just wanted to comment on the hang-up on starting issue you mentioned in one of the vids -- I have had three 4F200s, and they all did it to one degree or the other. I think the Walkera ESC and motor have a timing mismatch (on start at least), but once you 'wiggle the stick' and get it going, as you must know yourself, there is no issue from then on, but it is annoying on spool up.
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Old Sep 10, 2012, 02:00 PM
IHW Heli Division
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Quote:
Originally Posted by tracknoob View Post
Great work on all that experimentation! Cool stuff!

Just wanted to comment on the hang-up on starting issue you mentioned in one of the vids -- I have had three 4F200s, and they all did it to one degree or the other. I think the Walkera ESC and motor have a timing mismatch (on start at least), but once you 'wiggle the stick' and get it going, as you must know yourself, there is no issue from then on, but it is annoying on spool up.
yes, I agree. Both of my 4f200s do this. after installing a new ESC it is still happening. I think its just the motor. the turboace 352 starts much better and runs much cooler. but does not output quite as much head speed using a 18T pinion. I consider it a upgrade since I live in Florida. On top of that, the ESC stays cooler, the battery does not puff, and you can expect longer flight times.
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Old Sep 10, 2012, 05:06 PM
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Awesome work! I love the multiblade setup. I wonder how this would work with a 3S setup and a bigger motor! Do most of the tail issues seem to be due to bogging or is it a tail servo thing?

How well does that whole huge head assembly balance out? Can't wait to see what's coming next on it!
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Old Sep 10, 2012, 06:55 PM
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Originally Posted by TucsonFlyer View Post
Awesome work! I love the multiblade setup. I wonder how this would work with a 3S setup and a bigger motor! Do most of the tail issues seem to be due to bogging or is it a tail servo thing?

How well does that whole huge head assembly balance out? Can't wait to see what's coming next on it!
They balance out great. Extra power would be great also. Yes it is from too much load on the rotor making the tail kick out. 3S conversion would allow for better 3D. Also having faster servos with lots more torque. The extra blades make the rotor disc harder to flip because of the extra centrifugal weight of the disk. It's like how a bicycle works to stay up right using the gyro force from the wheels. If there was more force or more wheels the bike would be that much harder to tip over. Same with the heli rotor. More force, more weight = harder to tip. So yes it flies more stable than the 4f200. I have no doubt it is capable of lifting more weight than a 2 or 3 blade rotor. That is going to work out nicely
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