throttlecurve

I picked up a deal on a Walkera 35#C (seems they come up with a new model no. for each unit built - so I guess I have the only 35#C ever built). LOL The 35C isa brushless motorNOR collective pitchbird with fly bar and beltdriven, pitch adjustable tail rotor. It has an anjustable Gyro. Tx is a 7 ch Wk-0701

I knew better than go try to fly it. So I've spent two weeks striving to achieve mechanical perfection checking and tweeking things, tightening all screws, centering servos, checking settings, adjustments, and bench testing. I found some parts installed incorrectly and many things way out of adjustment.Balanced rotor blades.Bought a pitch gage and set pitch to-2% / 0% /+5% in normal mode and -9% /0% / +9% in acrobaticmode. There'sno way this bird would have ever flown. (Perhaps that's the reason I gotthe deal).

I've also done a bunch of searching & reading these forums- and spent about an hour on the simulator at a local hobby shop. (That's how I learned not to try to fly it out of the box!)

I built a string teather for training skids to hold the bird down to aboutthree inches. I've throttled it up and lifted its skids up against the teather strings and learned to stay oriented and gently set it back down in the same spot with all four teather strings slack.

However, everything I learn seems to spawn two new questions. Some guidance on the following would helpme get closer to 'un-teathering' my heli.

1. While balancing the main rotor blades, I find thatthe main rotor blades shouldbe mounted with some give and not TOO tight. But if they are too loose, the motor torque distorts the balance during run-up and during abrupt accelleration - resulting in very serious balance shake. But how tight should the screws be?

2. I have blades balanced& trim adjusted where it will lift off level without alieron or elevator intervention. However it required quiet a bit of right alieron adjusted into the swashplate (it's visably tilted to the naked eye) to lift offwith neutral txstick and alieron trim centered. Would this be "normal"cause of engine torque, that cannot be adjusted out mechanically without consuming 10-15 percent of the right extent of alieron? What if Iskewed the main rotar shaft to the right a few degrees?

3. Transmitter parameter adjustments (PIT Lock, Gyro Sensitivity and Rudder Mixing, Throttle Curve and Servo Exponential) have blown my mind. I think I accomplished the PIT (Pitch) limit adjustment - according to the manual which instructs turning "Dip Switch 10 Off to 'lock' the PIT parameters you have set." But setting the Gyro sensitivity/ Rudder Mixing/ and throttle curve leaves the reader seriously hanging and confused. I'm assuming I need to set these parameters since so many other things were out of whack.So, what action(s) 'locks' or 'sets' the setting after you have followed the instructions? Returning Dip Switch 12back to the OFFpossition? If so, is the same true forThrottle curve withDipSwitch 11? Does that mean Dip Switches 10, 11,and 12 ultimately should all three be in the OFFposition for any and all desired flight modes?

YOU SEE. THE MORE I LEARN THE STUPIDER I GET.

Perhaps if someone can help me out withanswers tothese questions, I can get ahead of the throttle curve and lift off without strings tying me down.

Robertwav1

Not true! Way too much information to digest all at one time. Go by the feel of the heli for now. Tighten the blades like you think they should be tightened. Don't worry about dual rates and expo just yet....slow down a little and enjoy the ride. Your learning how to fly and that's a good start. The other stuff will come as your learning. I've always liked tightening the blades on the smaller stuff I used to run however, got to make sure there not so tight that they can't straighten themselves out at a high head speed. Untether the thing, run everything linear and make adjustments one at a time and understand that fully before moving on. Radio programming is complex and there is a learning curve. Enjoy some fight time and getting things trimmed mechanically first. Swash should be level mechanically, if not, something is not 90 degrees at midstick. Go over the head setup again and again. There's videos out there that are priceless and will answer all your questions. Again throttle curve linear for now 0,25,50,75, 100 normal mode. Pitch curve normal mode -2 degrees to zero degrees at mid stick generally speaking. The manual for your heli should tell you what initial setup should be.

throttlecurve

Thanks Robertwav1 

     You've helped.     I think I'll loosen rotor blades a little bit.   They're probably not auto straightning.   I had to throttle up numerous times after straightning one or the other to achieve good smooth balance.

     But untether the thing?     Please.   Let me do the RC shop's simulator a few more times first - and for sure I NOW want to understand why, after all my dilligent efforts balancing, centering and tweeking things mechanically, my swashplate isn't level to achieve level liftoff.        Once that's accomplished I think I will try untethered hover for a couple of battery charges. 

throttlecurve

Robertwav1

Okay...lets start with the swash. Look at the cyclic servos that move the swash when mid stick on the throttle, motor unplugged, linear curves on the radio. The arms on the servos should be at 90 degrees, all three of them....same thing. If the arms are not, move them mechannically. If mechanically they don't jive then use the trim setting on the radio to get them there. Next your linkage rods (ball links) usually in the manual for correct length, need to get this right. On one of my builds it drove me nuts cause I made a mistake in measurement so double check this. I never used a swash leveler, always went by eye which works for me. Get this part right first...swash has to be level and after that is accomplished check movement of the swash in all directions. One of the things that was pointed out to me was to make sure the ball links have no binding as well as the washout assembly. Everything must be free and smooth.

Real2You

One noob to another.....How can you get a level/balanced take off with the heli tethered? Does'nt the wash from the main blades cause the heli to drift a little? In theory.....you could have a great setup and still have an erratic take off until the heli gets in the air a few feet.

throttlecurve

Real2You

      You raise an intresting point - one that I cannot answer.    I've read about "ground effect" but have NO idea what reaction it impose into the equation or what it would "feel like".   More on that momentarily.       

       Robertwav1   I'm going to do everything you suggest again because I want to get back to perfectly level swashplate.    Honestly, I think the maticulous steps I originally took was just about everything (at least what I intented) that you suggest.    However NOW I have screwed up the adjustments trying to achieve flat hover without stick intervention (in what might be an unrealistic environment per Real2You).

I built the tether thing by fixing a round (23" dia) plywood board mounted on top of a five gallon paint bucket.      Each of the four landing gear "trainer wires" are tied to the board by staples about three inches, (right under each orange ping pong ball) with about three inches slack.       The craft can't tilt enough or go anywhere to hit the main rotor on anything.   And I haven't torqued it up hard.

Upon very gentle rev-up the craft will get light on its feet, without counter-rotating AT ALL, and gently rises (lighter on the right side), and I can hold it steady with some right aileron.    I've adjusted (or mal-adjusted) most of that out at swashplate adjustments, but it aint level at idle anymore?       And I can hover within the string lengths with gently adjustments even though I would say I'm still feeding mostly right aileron in to hold steady in place.

IM Scared to just cut it loose yet.     Am I being TOO paranoid?      Perhaps I should execute Robertwav1's suggestions and just go for it?

throttlecurve
<script></script>

Real2You

When Iwas learning to hover, my Raptor 50 would move around when it got light on the skids or was lets say 1 foot off the ground. When Igot it about 4 feet off the ground it got very stable and was a lot easier to keep in a steady hover. The wash from the main rotor blades caused all the air disturbance and made it harder to keep in one spot. So to me....if you are "messing with your set-up" when it's tethered.....you are not getting a true set-up. Level your swashplate...servo arms at 90 degrees....just do as your build manual says. Then get used to the controls by getting it light on the skids(I am assuming you are using training gear).....then go for it and get it up in the air a few feet to get out of the heli's wash. Good luck!! It's an adrenaline rush the first time you hover a whole tank of fuel/battery.

throttlecurve

Thanks to all for the good ideas, suggestions & moral support.

I'll get the suggested adjustments redone and try lifting off the ground some still morning this weekend.

A good friend of mine, (who is licensed to fly real helicopters, but not into R/C's) told me that hovering near the ground is akin to trying to stand on a beach ball.    He also suggested that if I can hover the thing in the propwash and sit it back down, athough he's not a modeler himself, he thought I certainly should be able to fly it mildly and the tx is probably tuned close enough like Robertwav1 suggests.    I just don't need to try any antics right now! 

Think I've got my nerve up so I'll report back how it goes.

Thanks again,
   throttlecurve

Gorgok

While your friend is pretty much right that if you can hover it in wash you can fly around easy enough, except for one thing that separates a real pilot from a RC pilot. As a real pilot he never has to worry about orientation. At least with RC helis you can piro it so fast back into a tail in hover that even that shouldn't really matter.

And yes, depending on conditions, hovering in your own wash is pretty screwy. Having some wind actually reduces the height you need to get clean air, but then if the wind stops you lose lift and drop...

1luckylenny

My Feedback: (1)

hello as a newbi my self to helis , buying,building,and flying,and rebuilding "after crashing" .lol I still might have some good in-put ?

# 1 after your swash plate is level ,at half throttle,horns are all 90 deg's ,make sure all servos work together and your shash plate stays level from top to bottom of your sticks travel . and no bind at all ,when you spin the head and move the sticks in all directions
.
#2with a level swash plate ,the fly bar should be levelalso ,

# 3 when all this is done make sure they both stay level all 360 deg,s when you spin the headaround .

#4 as for your blades ,A you want to hold your heli 90 deg,s, with the baldes tight enough to holdstright out to the sides level to the floor.

B ,with it still onits side, now with a quick littlejurk" up or down" with the heli" about a inch or so " the blades should just drop slowly !

# 5 spend more time on a sim ....... less time watting for parts, or worse yet giving up the hobbie !! ebay has flight sim's with about 10

airplanes and 3 heli on a disk, with 4 dirfferent cords to plug into any type transmitter for around$ 10 . I have the r/f g3 sim and the ebay

sim's not the same but its ok ,Only this will not work with vista p/c's Hope this helps len

throttlecurve

*
* * *   C R A S H E D  * * *  ! !
*
      Pilot was the only survivor!    Injury confined to brused ego the result of the short time it took to slam into the trunk of a tree (4 seconds).    Lucky for ME the darn thing is "remotely piloted".       [ I will read 1luckylenny #5 again - and again].      

    And thanks 1luckylenny for #4.     That gives me a reference point to work from.     My blades were much tighter than that  (but I guess they would have broke upon smashing into that Red Oak tree anyway- Ha).    I may also have an issue with throttle curve (no identity pun intended) or something.    The motor "leaps" into action upon throttle up and would slip the blades.     After that, it will idle back down and run very gently, but if the blades slipped during throttle insertion it was way too mal-balanced and would hop all over the place.    Hence, I kept tighting them a little at a time.     Question no. 5,000.    Should the tx throttle start up from a very gentle idle?   Or is it common for the motor to start pretty strong (perhaps 10%)  then be able to back down to maybe 2% - 5% power? 

    This Heli had been crashed before I got it.   (The seller disclosed that.)    In fact, there is a brand new c.n.c. metal main blade mechanism and new blades in all the stuff I bought.  But I elected to stay with the original plastic head mechanism calculating that I probably would bust it once or twice.     There are still enough parts to fix the plastic mechanism from my little mishap.     I'm undecided installing the nice metal head at this time.

    However, there may be something 'streached', 'warped', or 'bent' that feeds right cyclic pitch into the collective pitch or something.   Verifying #3 suggestion of  1luckylenny is well taken and may be related to this and my crash.     When I got the Heli equally light on the training skids, I had some right aileron already on the lever.     When I increased throttle to lift, it took off smartly to the left,   I knew I was in motion too much not set back down.     And I didn't get adjusted quick enough then SMASH in a FLASH!

   Hovering in the wash may be screwy Gorgok  but I got a better chance burnning up a full tank of battery that way (with strings holding it down)!   lol. 

   Oh well, I'll fix it and try again.    Like everybody says.   That's half the fun.

Again, I appreciate everybody's input.  You guys, whether you're a newbi or not, help keep me determined to figure it out.


Throttlecurve 

jmann71

hey throttle curve. sorry to hear of the crash. To answer a question that doesn't seem to be getting answered. it is nearly impossible to get the heli to lift straight up with no inputs. is the ground perfectly level. mines not. slight breeze, countering toque. plus in hover you have the "push" of the tail rotor and you will always have a skid low. they never sit level, not even the real ones.

sorry that was broad, but hope i shed alittle light.

Gorgok

Related to the crash and the posts above: Once you have the swash level and all that nice stuff, as the above poster said, the heli will not fly straight up, rather it will lean left, and get pushed left, and gain speed doing so. Since you know the mechanics are set up all level (following #1, 2, and 3), you should add some trim to the right on the ailerons to counter the left tendency of the heli. This part can be tricky to do unless you can get a nice hover and can surprise you if you don't expect it. What i would do is apply a few clicks of trim, hop it up a little, ready to add right aileron and see if it is enough to counter the tendency. Set it back down and add more or take some off depending on which way it goes. You can get it pretty close, but it will never hover without input. But close is much better than streaking left.

Once you have it, the heli should be visibly leaning towards the right, but just a bit, and stay fairly steady with a slight drift to the left or right (depends on the conditions). But it sure makes it easier to fly when you don't have to hold right aileron all the time.

This could even be practiced/checked on a sim, at least i have a few clicks of right aileron on my sim setup on the transmitter.

Same could apply to the elevator trim, unless you manage to get the CG of the heli dead center of the mast, it will want to go forwards/backwards. Mine is nose heavy, and has a bit of down trim on the elevator to keep it pretty stable even without any input.

1luckylenny

My Feedback: (1)

Throttle curve !! I sure feel for you my friend !! Sounds like you were trying to fly in tight quartes ,if it hit that fast .? "A - NO - NO" !

Hope you can get it together ,and set back up soon ! In the mean-time ,Dont just read # 5...lol That will not cut it ! Check out

Flee- bay for that cheap sim ,for less then $10.00 you cant go wrong ! and Oh Yes !!That week or twoof hours on it helps!

As for throttle up = it all depends on where your throttle is when you flick the switch ,and if the transmitter you are using has mixing ,

this can have thrown everything way off , If youdon't have it all set up right ! Thats where Iam at now, trying to set up my mixing.

Use throttle up around 1/2 throttle "hover" or just before ,This way the bladeswill be up to speed ,and should not be much change in

rpm andblade pitch . You might want to stay in normal mode at frist ?

Iam not sure what you meant by blades slipping ,if your motor is running smouth and it slipps ,Check inside your clutchfor wear ,oil,

broken parts...

One more thingI wouldlike to add at this time, is your gyro . WhenI turn on my heli "after transmitter'' I have my gyro turned on

head-lock mode ,and after about 5 to 10 seconds switch it back to head-hold for normal flight,before i start it up. Hope this helps ??


Keep thequestions comming !!! That way we know your still at it !!

Druss

Well... some good set up tips so far but I will add a couple of things.

The swash should be level and don't use trim unless you have to. You should ALWAYS have to add some rudder and cyclic input to keep it straight, this is only on take off and once you get into a hover 4 feet from the ground the left push and tail wanting to swing counter clock wise (viewed from top) is gone.

The reasons for the two are as follows: left movement is due to the tail blades pushing the air to the right and therefore the heli to the left, this mostly disappears once you get above a few feet; the second is the heli frame wants to rotate in the opposite direction of the blades, that's why you have tail blades to prevent this rotation but when you first spool up the blades aren't spinning fast enough to accomplish on their own so adding some extra pitch to the blades helps prevent this. Once the head speed on the main and tail blades are higher this also disappears.

My suggestion is to keep with the sim but also go through radd's school of rotory flight (google it) and follow the directions, he talks (writes) a bit weird but just follow the steps and you'll get a feel for what the heli will do.

throttlecurve

Thanks for the good feedback guys.

I haven't given up.   I decided to pick up a cheep set of blades and repair/stay with my plastic head for now - instead of rebuilding it with the Metal Head and carbon fiber blades that I got with the original heli purchase.

jmann71, I admit I have had the misguided notion that I could achieve "gentle liftoff" with little to no intervention.  Some of that came from the 3 inch tether strings.   Merely bumping the end of a string cancelled out drift in that direction.    I would not have thought such a gentle tugg would correct its attitude judging from how swigtly it streaked off into that tree without the tether!     Your reminder how "real heli's" take off makes sense - the skids are never level - so surely they would drift off rapidly if the pilot wasn't correcting for it.

And I think I realized the natural need for correction - but newbe slow fingers just weren't ready for the quick response.        Yes, I probably was in too close quarters 1luckylenny.     But really!  It only took about four seconds to reach that Oak tree about 30 feet away!    (Seemed like a long way when I sat the heli down.)      But the SWITCH?      I'm not ready for the switch.      I'm leaving it in the normal mode except for bench testing holding the thing down.    I even have the Normal/3D switch tied down to Normal with a rubber band when I test it via the tx.     But in Normal Mode, when I throttle up "very gently", I get NO action until about 10% throttle - then it jumps into action (about 300 rpms).    It will not "lift off" but starts turning smartly (enough to slip the main rotar blades in their mount unless the mounting screws are tightened enough).     If they slip it throws the balance seriously off.      But, after the motor is running, I can throttle back down to just a trickel (maybe 60 rpms) .        Some throttle curve adjustment needed????
 
Thanks Druss for the technical insight to its flight charastics.    I'm an analytical type and if I can understand I can deal with it better.      {The clockwise rotation (from above) of the main rotor blades induces a counter clockwise rotation (thus rightward force on the tail) and consequently a leftward force on the nose.   This much I've always understoon - the equal and opposite reaction stuff.       Now when the gyro (or pilot) puts a counteracting right force pushing the tail to the left to counteract the counter rotation   you now have left force applied to both the nose (from the counter rotation) AND tail from the tail rotor!       Hence - being pushed left on the tail AND nose, the whole craft drifts off to the left unless proper cyclic action equalizes that reaction     These forces would all be amplified during "acceleration" of the main rotor speed because of additional torque.   }    Did I say that right???        

I'm looking for a sim.     It's too slow going to the hobby shop to use theirs occassionally.

I'll report back soon.


Thanks,  Throttlecurve

1luckylenny

My Feedback: (1)

Throttle curve check out this site, lots of great info here .http://www.helifreak.com/showthread.php?t=41692 and for the sim ,go to e-bay and in

the advance screach " on the right of screen"copy and past this number 160383821952 This will bring you to the sim i refer to.

Check out that clutch, seems like it comes on to hard, ifit jurks that hard. check the bell as well as shoes, seeif the shose have been bent

in,even a little will make the motor spin up muchmore beforethe clutch will ingage.

also you might have your throttle curves way out "no punt intended" LOL a 5 point curve should look like this 0 ,25 ,50 ,75, 100 . in normal

mode . a 3 point would be0 ,50, 100 . So at half throttleand 4 to 5degrees pitch on main blades ,the heli shouldnotoverrev

Two more thing mightbe at play here , # 1 thorttle travel = end points and binding .???? and # 2 exponential, no more then 20 percent

at most is needed in mode #1.. Maby 5 to 10 percent for the slow hands,by the way "slow hands " are what you want in this sport, it makes

for a smooth ride, you might need more in3/D mode ?? When we get there ,and we will,, dont give up ,makeit fun! len

jmann71

ok 1luckylenny, i am really not trying to be a smart ass, but he has an electric heli. no clutch. i do believe though that your throttle curve is incorrect though. it shouldn't snap the blades like that.

throttlecurve

Yes, it's an electric jmann71.     It's a Walkera #35C stock I figure though don't know.    I haven't taken the main mechanism apart where the main gearwheel is - other than tighten the screws on the electric motor ( a WK-WS-26-01 / 3500 ).     I haven't seen what I would perceive as a 'clutch', but for sure when I shut the throttle down abruptly, the main rotor will coast (freewheel) and I know the motor is not turning.     That's some sort of a "one-way" clutch isn't it???       But when I throttle up from OFF position, the motor gear is NOT move at all before it jumps into action.     So I haven't spent any time pursuing a 'clutch'.

The transmitter (a PCM  WK 0701)  throttle lever will move up to the first little "tick mark" on the position indicator (there's seven little tick marks) before the motor does ANYTHING.     That would theoritically, (in a perfect world) be about 15%.        Any more throttle - & - wham.    It springs to life at roughly 10% (or maybe 15%) - somewhere around 300 rpms.      That would cause the main blades to slip in their grip and - boy it would jump all over the work bench even hard to hold down.      Anyone would immediately shut the throttle down.       Not knowing what is or is not right, my solution was to tighten down on the main rotor blade screws until they would not slip under this condition.     Then it runs real smooth and can rev up or idle down.    But I am concerned that they won't give easily enough when I tip it over (or god forbid) hit another oak tree!!!!

I am thinking there is some adjustment on the transmitter that I haven't learned that will affect that action.    Anyone know a procedure to check or set that?

Throttlecurve

jmann71

there is a one way bearing in the main gear, this is for auto rotation in case you lose the motor or speed control in flight you can still land safely. i thought i read above that you played around with the curve or was it a question about the curves?? if you need to adjust the curve than we need to know which transmitter you have.

1luckylenny

My Feedback: (1)

Sorry i should hve look closer at the frist post ..".dahOn my part " its your speed controller . it is set in a hard start mode ,might even have the brake on when you throttle down ?go through the set up with all the beeeeeepppppppss lol and set that up for soft start and no brake and no cut off point. wherewhen the battery drops too low so will the heli , ask me how i know ?? better yet ,picturea 75 footor so,. stright down drop ,throttle stick pushed to the top ,and all you can do is watch it smash to pieces in front of you !!I "Think i made up a few new swear words''
After though !!!about 1 second after it hit the ground,,I should have tried to autorotate ???? Works on the sim sometimes,, sure would have saved some parts.. hope thishelps len

jmann71

alright, read your manual. you have the stock radio right?? 1. turn dip switch 10 on. 2. flight switch to normal. 3. V1 (right hand) knob to 0. 4. V2 (left hand) knob to 0. 5. without moving knobs, set dip switch 10 to off. this should set the radio up correctly "default". but, if the motor still comes in late, repeat above and try turning V1 to the "+" side.

hopes this helps.

Jason

jmann71

lucky, i went through the entire instuction manual on the walkera and couldn't find anything on the soft start or brake. i know that after market speed controls have these but i don't believe this one does. no mention of it what so ever. i know my stock esky speed control doesn't. if the walkera does, can you give complete instructions. Thanks Jason.

1luckylenny

My Feedback: (1)

Hey Sorry for the slow return!!!   I just had a look at the manual, for the Walkera   #35~C . 

  And all i see, is the set-up for  the  " throttle"  is in the dip switch .and  the V-1 , V-2     ,  Under     P I T

 AS  = Switcht # 10 to On,  L E D becomes light blue ," this part , Iam not to sure of  AS  the # 11 AND # 12 SHOULD have been off " defalt setting "

  but  it states switch #11 and # 12 to off ?? 

Then Rotate   v1 and  v2  To  center  or  - 0  middle of adjustment's 

 after that set # 10 to on     Thats it ,   your all done! 

   Defalt Setting for dip switch is

 # 1  = on
 #2= on
 #3=off
 #4=on
 #5=off
 #6=off
 #7=on
 #8=off
 #9=off
 #10=off
 #11=off
 #12=off 

 Hope this works for you ???        len

throttlecurve

Hi guys.

     I'm back!   Repairs are all done!      Swash plate is level!     Servo's centered at neutral!    New blades are amazingly balanced and smooth after perfect adjustment of pitch & tracking.      I Got the throttle curve set where startup is smoth and gentle ( 1luckylenny , it seems to me that Switch 10 must go to OFF after setup of throttle curve, {refer to jmann71 above}  if I do not, subsequent movement of V1 & V2 screws up my throttle startup again).   Anyway, 10 is OFF and working like I think it should.   V1 & V2 adjust throttle / pitch action like the manual graphs show.

     I went back to the 'tether' for checking everything out.    I can raise the skids level by following advice of Druss  ( only 1" so far because of lack of nerve after the crash).

    1luckylenny,  I ordered the SIM & Cable off Ebay  [  http://cgi.ebay.com/USB-Flight-Simulator-FMS-Cable-JR-FUTABA-ESKY-RC-/160383429707?pt=LH_DefaultDomain_0 ], but it will not work with MY Walkera WK 0701 transmitter.       The cable pinout on the DIM connector does not match the transmitter buddy plug pinout  PLUS, my Walkera transmitter is PCM coding, and the USB interface from that vendor works only with PPM coding.     I performed the 'mod' suggested on a YouTube video at http://www.youtube.com/watch?v=-JrUSb1jJg0&NR=1  explaining how to change connector pinout to work with Walkera 701, but the video poster's transmitter must have been PPM coding, because the mod did not work with my transmitter even after changing the plug wiring according to the video.
    At this point I'm not sure which way to go with FMS Simulator, but am corresponding with a website in Berlin Germany who appears to have a USB interface (USB Interface III) that is supposed to be compatible with Walkera WK 0701 with PCM coding - AND is compatible with several Windows operating system's standard USB drivers for HID gamming devices. 
    
     They are www.MFTech.de .      Anyone know anything about MFTech.de??????


Thanks,  throttlecurve