Why is factory throttle curve linear?

[nyc_863]

So I'm watching these trex setup videos by finless bob.

He convinced me I need to get used to a 0-50-80-90-100 throttle curve as this is normal for electric helis. So why is the factory curve linear?

[sokal]

its not as dramatic as a speed change
if in idle-up stock and bobs style are fine
the diffrence is with the higher head speed you will have better tail authority and less of a rotor droop
the rotor speed changes as u move the stick with it set higher at diffrent stick positions
makes controling up and down movements more responsive as the blades rpm doest have to change as much

i suggest if your qiute comfertable flying
(make sure u know where the throt hold switch is and quick to get to in case of run-in with ground)

is to fly in stunt u will see the diffrence. as the head speed in more constant
lil change in head speed helps with control

if your good at a hover try it a few times at a hover.

[nyc_863]

well I tried it 0-50-80-90-100 and it felt too twitchy. Any trim issues or dumb thumbs seemed to be magnified too much for me to handle especially with looming walls and ceilings. So back to stock on the throttle curve.

I changed the wooden blades for align CF, and I moved the tail servo one hole up on its mount and one hole in on its horn, and chopped the end of the horn off, for clearance.. Then I was pleased to see full rudder no longer was binding in either max direction. yay!

Then I mechanically centered the rudder to mid stick, with gyro disabled.

then I eliminated rudder creep under throttle-hold and heading hold on (I don't understand "creep" at all, to be honest. I don't understand where it comes from) by sub-trim set to about "10". I also turned up the gain pot to 100 because I'm told the radio controls the gain so the gain pot is ignored, but finless bob says the gain pot can "confuse" the radio input if it isn't 100. Shrug. So 100 seems like a safe choice because it offends neither explanation.

Then went back to hovering in my large apartment-block garage and I was much more pleased with both the sound and vibration (CF blades just feel slick) and more importantly the tail was behaving and I could hover with some right stick input in a stable manner either in ground effect or 3-5ft off the deck.

I'm still not sure if the gyro is capable of really *locking* onto a heading though.

If the tail drifts very slowly with no input is that because the gyro is being commanded to do an extremely slow piro, or because its idea of its starting orientation is slowly drifting over time, to eventually do the entire 360 degrees?

If I trim or thumb out that movement to *look* totally locked on, does the gyro now think I'm commanding a very slow rotation?

I know it shouldn't really matter what is going on internally if the heli looks locked to a compass point after a click or two of rudder trim ... but I want to know what the gyro is reporting as "input" (v slow piro? or zero piro?) and where it believes (after minutes of hovering flight) its starting orientation was. I can't get either bit of info directly though.

Another thought experiment: if these gyros drift - which i can understand - if you turn it on on the bench with throttle hold on, and leave it for some time, then come back to look will the rudder have moved fully from center to try to "get back" to the drifted start orientation? if not, then why does the gyro, with no rudder commands, let a drift from init orientation happen at all? if the HH gyro is a computer program it is a loop that says: compare measured orientation with desired orientation, take the delta in degrees and decide how fast we want the tail to get there, command tail servo to move if necessary all the way over, pause a millisecond, go back to the top and do it again.

Sorry if you read this far for the barrage of questions, this stuff is off the topic but I'm dying to _fully_ understand heading hold, creep, drifting tails, and so on, rather than just have a bunch of heuristics in my head such as "if it does X, then adjust Y".

[skigolfmike]

By setting the normal throttle curve to 0-50-80-90-100 it will match the idle-up throttle curve from 1/2 stick up. In theory, you could hit the idle up switch in hover and nothing would happen. Great in theory.

I tried that, and, like you, thought it was too touchy. However, I did not like the stock curve either because I felt it was hard to hold a steady altitude in hover. So, I ended up trying 0-40-65-82.5-100 and that worked really well.

I think the reason the collective is so sensitive with the stock throttle curve is because the head speed is too low and because the throttle curve isn't flat enough at hover. It's kind of a trade-off though since faster head speed makes the cyclic more sensitive.

One other thing to look at is the shims on the feathering shaft. My 400 came with spare washers installed. It was like having 22 shims/side instead of 2. Needless to say the head was very stiff and it was super sensitive. It's better with 2 shims/side.

[sokal]

i use the 401 most of what u say happens when in hh mode. i have 0 sub trim and o trim all drifting adj is done out of hh mode and with the control rod.

while in hh mode and u give an input yes the gyro is thinking your turning and will do the creep.

do as u did gyro down below 50 so that u will be in rate mode servo will ast as you would think a servo should. that way u can find center.
center is not blades 0 pitch its the slider itsself centered beteween the rotor and tail rotor case.
i also use the 3400g as my tail servo which is strong and fast and can keep up with gyro compensations.
if anything i would recomend a full digital servo for your tail. ie JR futaba and the spectrum 75's all inable u to use the DS mode on your gyro witch is a huge plus.

if your in hh mode and u give a touch of trim to help with drift the gyro reads it as an input
not servo center.

so if u see a drift adj the rod half turn at a time
hope that helps
also the gryo u have isnt bad its just the 401 is more capable and reads the drift faster and resopnds faster but please change that tail servo mine burned out after 15 flights

as for the sensitivity of the heli
i use my thumbs and pointer finger on each stick for me it helps me be more pricices with movement
as for when i flew with mu thumbs i over controled the heli if you fly with your thumbs try the two finger method
for me once im a good flyier will move to thumbs so i can have the faster movement speeds for extreme 3d