MadHans

Hi

I have a Raptor 50v2 w/OS50SX-H, and are experiencing some problems:

When I do a full power vertical climbout the RPM is increasing, and I want the RPM constant over the entire throttle range(1/4 stick to full stick). It sounds like overspeeding of some sort...?
My pitch curve in normal flight mode is -4,5,10. Hover at 1/2 stick.
Engine settings: Main needle: 1-1/4 turn. Idle needle: 20-30 deg. on the rich side. Engine has smooth transition with quick response and a steady idle.

After some full throttle circuits, I land and touch the backplate. I can hold the finger there as long as I want. Therefore, I have never beleived that the engine is running lean at the top end. But maybe I am wrong here... because somebody tells me that if RPM is increasing when doing climbouts, the engine is too lean...

But I´ve also been told that the OS50sx-h is so powerful in a R50(power-to-weight ratio is high) that you have to back off on the throttle curve at the top end(e.g. to 70% or so) to make the RPM stay the same.
I´ve ALSO been told that you should never fiddle with the throttle curve (only the pitch curve) to reduce top end RPM to the same as hover RPM.

This is where I am getting completely confused:

What to do? Engine mixture? Pitch? Throttle?

How do I determine what causes the problem? Are there any good procedures to follow in order to solve this confusing problem?
How can I eliminate whats NOT the cause? When the engine is overspeeding at the top of the climbout, what do I have to adjust to get it better?

And when setting up the helicopter; do you guys get the pitch curve right and then tune your engines to get the RPM right, or the opposite? What about the throttle endpoints? Whats first?

I really hope somebody can help me out here. I don´t wanna ruin my engine.

Thanks in advance

Best regards

Hans Jacob

BarracudaHockey

My Feedback: (11)

Throttle end points should be set equal sides of center and in the 80 percent range. If you are over 100 move the ball in one hole and readjust.

For the pushrod measure the distance between the center of the throttle arm and the center of the servo spline, make the ball to ball distance the same and your pushrod will be perfect.

Set your pitch curves first, adjust head speed to suit using a combonation of throttle curves and needle adjustment.

The 50 should pull between 9 and 10 degrees pitch with no problem. You can reduce the high end throttle curve a bit but make sure you have cylic mixing turned on so that you can get full throttle when giving control inputs as well as cyclic inputs.

As I responded on RR read http://www.raptortechnique.com

Finally if your flying has progressed far enough, an rpm governor costs about the same as a set of carbon blades (i prefer the csm revlock but the revmax, throttle jockey pro and gv1 all work well) and you can set rough throttle curves and be done with it.

Motions

That's a good explaination for setup Andy, but I can't see how you can over speed while putting in +10 deg pitch. I have mine set to 100% throttle at +10 deg and I loose a little head speed. It sounds very much like it's lean but if it doesn't get hot, I'm stumped.

BarracudaHockey

My Feedback: (11)

It could be lean at full throttle but if you hover around or auto down or let it sit and idle it will cool quickly.

The advanced engine tuning section on RT is a very detailed tuning how-to.

Also if its a hyper it could surly overspeed at +10.

jez33

andys description for setting up a v curve is pretty good there so i dont think i need to add any thing here.. a good method ive used and seems to be good is to bolt/tie/fasten your heli to a table or ground and go through the throttle pitch settings on the ground...youll still need to fine tune it in the air but it cuts out loads of mucking around time...

oh i almost forgot.regarding the lean running.. while your heli is tied downd look out for smoke from the exhaust at all positions of the throttle..if the smoke becomes less or stops then it can nearly always be attributed to being to lean so either/or both the mid or high needle valve settings need to be richened,you want a good plume of smoke so to speak at all position's of the throttle stick...

KC36330

you can definatly overspeed a 50 SXH with over 12* top end pitch, blade design/weight has everything in the world to do with it here. the posted setup has 9* travel between low and mid stick and only 4* from mid stick to top end and flattening that out some would definatly help with the problem.

first thing when starting all new is to set the radio so you get equal travel from low to mid and then from mid to high sticks on BOTH throttle and collective. then divide your total collective travel by 2 and that is what you should have at mid stick. i don't know what the hang up is with some folks that you have to hover at mid stick, all mine hover very slightly above mid (slightly below for inverted) and anyone who has progressed past learning to hover and plans to do any sort of aerobatics/3D/inverted should then learn to fly with 0* at mid stick. then adjust your throt curves for the desired rotor RPM you want in any particular flight mode.

I've been away from this board for the past 5 yrs (it was rc online when i left) and i can't help but notice that allot of posts incline that less experienced people should use different pitch curves for different flight modes, this is one thing I've never agreed with and never do. i fly max collective travel with the same pitch curves in every flight mode, that way the heli's response is always the same to stick input and regardless of the situation that arises i don't have to worry about flipping a switch to have the correct pitch curve to save the day.

kc

Motions

I agree with KC. You should setup your pitch and throttle curves correctly and tune your engine from there. I'm not sure why people recommend hovering at mid stick, it just doesn't make since. Once you get to acrobatics, it's really going to screw up your learning. All modes should have the same stick positions.

BarracudaHockey

My Feedback: (11)

Different people do it different ways, no one way is "right".

I use a flatter pitch curve on the bottom for normal mode because it desensitizes the collective stick for practicing precision hovering type stuff, it just looks better when you are flying. I also only run -5 in hold because any more it just drops like a brick with no gain in rotor rpm. I do make sure to set the mid and 3/4 pitch points the same for all flight modes so theres no jump, the hold having +12 at the top.

I seriously doubt you are going to over speed a 50 with 600mm blades at 12 degrees, more times than not you would be bogging it down. If you are one that for some reason wants to run a short boom with 550's then sure, you could do it.

MadHans

Thanks a lot for your input, guys! Really appreciate it!

Hans Jacob

tippy

However ... it does make SENSE especially for the beginner that may be a little too quick on the stick responses.
Hovering at mid-stick means about half of your stick movement is from hover to full up. Changing to hover at 75% stick means you have only a quarter stick movement from hover to full up. This cuts the stick resolution (from hover to full up) in half. This is OK for the experienced but could be a bit tweeky for the beginner. Once a pilot has doffed the beginners outfit, by all means put 0 degrees at mid-stick and fly the dickens out of the thing.
What makes you think that every heli pilot has the same goals to do acrobatics? All I hear is "you gotta put 0 at mid-stick" or "you gotta make all the modes the same", etc. Well I've been flying for almost 6 years and guess what ... my normal mode is still close to where it was a few years ago.

The only thing you gotta do is fly safe and fly the way that makes you happy. Everything else is pilots perogative.
Are you telling me it's harder to learn the change from mid-stick hover to 75% stick hover than it is to learn let say inverted nose in hovering?
I don't disagree that it's good advice to readjust your normal mode so that it resembles the top half of your advanced modes. I just disagree that it'll "screw up your learning". By the time you've gained the stick savy to transition to advanced modes, the transition to hover at mid-stick to hover at 75% will come pretty easy ... in comparison to some of the manuevers you'll be doing next.

Good Luck,
d.tipton

Motions

Damn tippy, can I pull the knives out of my back now?

I just mean, IMO, it's best to start with a certain setup and stick with that. if you learn to hover at 50% for 2-3 months then switch to 75%, there's going to be a learning curve to readjust.

I personally use 5/8 as my hover point. It brings your +/- hovering pitch closer together and still gives better resolution on the rest of the curve.

This is only my opinion.... don't flame me please. [:@]

KC36330

I've only been flying heli's for 16 yrs but none of mine require 75% of the stick to hover just because 0* is at mid stick, i fly mostly advanced 3D and the sticks are 90% of the time between 40 and 60% on pitch. collective is ONLY to give rise/fall/holding all flip/roll/tic/toc/etc.... is done at 0* with cyclic only, one side of the rotor disk is pushing while the other half is pulling so you don't need or use collective to accomplish the maneuver only to give the 'bump' prior to cyclic input and hold it at the correct altitude after it flips.

kc

BarracudaHockey

My Feedback: (11)

After carefully watching a truly advanced pilots' transmitter as he was doing some wild aerobatics (Marcus Kim) I was surprised how little he appeared to be moving the sticks.

Motions

That's the secret. Once you master collective management, you don't move the stick much at all. Timing is critical and I'm not at the Marcus Kim stage yet....maybe ever.

KC36330

i think allot of people who haven't progressed far enough along into 3D flying are under the impression it's allot like a model plane where you slam the sticks to the extremes, it's more finessing of the sticks with a heli and using all controls to their maximum efficiency. continuous axial rolling of a heli from one end of the flying field to the other is 95% cyclic, 5% collective (I'd guess less then a 4* total collective movement between + and - pitch) but watch most newbies do it and you'll see collective getting worked hard up/down and they are just holding in full left/right cyclic only.

kc

tippy

Not "arguing" settings, just disagree that it's a major hassle to re-learn a different hover location on the stick. Image the first time someone was flying around in normal and switched to idle up in flight. How long do you think it took that pilot to learn a different curve response? Probably just one flight ...

Hover near 75% only assumes a near linear curve (huh?).
IOW, hovering at 50% stick, in order to get from 6 degrees (starting hover pitch for the R30) to 9 degrees (just a guess) is a 3 degree change. 75% stick would be half the change or 7.5 degrees.
Now if 0 degrees is at 50% stick, you would have 9 degrees of change. Half of the change (4.5 degrees) would land on 75% stick (still assuming linear curves and servo movements). So, without inducing a curve (non-linear), hover pitch would be well past 75% stick.

Of course, if one should envoke their pilot's perogative to make their curves the way want, then my position goes out the window ... doesn't it?

Motions ... sorry, I didn't mean to sound so gruff ... my bad.

Good Luck,
d.tipton

KC36330

a Raptor 30 that takes 6* to hover has one of two things happening, either it has a head speed of 900 RPM or a brick tied to the skids. using a liniear pitch curve with low stick -9 and 0 at center and +9 on top a R30 with 1450 RPM head speed will hover at + and - 3* VERY slightly above and below 50% stick.

kc