Pitch / Throttle curve confusion - HELP!!!

[Skipper Billy]

Hello - returning newbie here. The last time I flew a helicopter was with a mechanical gyro that was considered state of the art!! It was - compared to Galloping Ghost radio gear - no-one under 55 will know what it was or how incredibly crude radio was before proportional gear was invented!!!)

I now have a Raptor 50 with stock everything except the blades (SAB carbon fore and aft) - motor is a OS 50 Hyper. JR 9 channel 2.4 radio, CSM SL420 gyro and Futaba Digitals. I am using 15% coolpoer at sea level in cool temps (Scotland).

I have set the pitch in a reasonably linear manner from -3 to +10 - half way stick gives 5.5 degrees hovering pitch. Checked with a Robbe pitch gauge on both blades.

I originally tried the throttle curve in a linear manner from 0% to 80% and the tail boom mounted tacho showed a hovering head speed of 2000 rpm (ish) !!!

The only way I can get a hovering head speed of 1550 +/- 50 rpm at 5.5 degrees is to set the throttle curve at 0% - 45% it hovers at 32% - 35% throttle - that cant be right?????? The motor is running quite rich at the moment.

I know its a fairly gutsy engine but I think I must be confused or doing something drastically wrong???

I do not yet have the confidence I once had to try a full power climb out with these settings or with full 100% power and 10 degrees of pitch.

Is this set up totally ballistic or am I doing something incredibly thick???

Any help, advice, guidance or poking fun most welcome!

Thanks in advance.

David.

[stumpe]

I may be wrong but you should have 0 pitch at mid stick with both ends of stick movement pitch being -/+ (-10 / + 10)

this could be the reason you can't get a good hover, try the above and set your pitch curves back to linear and make sure throttle curves are ok, not sure how you like throttle set but I like to take off just after mid stick.

not sure on headspeed though as I run a 500 elec (2500 headspeed)

Lee

[SteveH39]

Go through the full mechanical setup, including throttle linkage, and set it as per the manual, should give you a reliable basic setup to tweak.

[Birdie4x4]

Hi, On my raptor 50 used for mild sport flying at mid stick 5.5 pitch it hovers with 38% throttle (DX7) so you are not far out, depends a bit on mechanical adjustments, however as pointed out above most flyer's tend to have 0% pitch at half stick so the transition to idle up has no big jump.
Hope that makes sense and helps.

[RafeyRJX]

Hi, a few things (i also remember mechanical gyro's - had one on vario 222) The engine your using is designed to rev its little nuts off, and will chearfully provide you with 1900rpm to 2100rpm head speed all day long. So 1550rpm is going to be way down the throttle range anyway. So your probabaly not far out.
What you really need to consider is what are you trying to achieve?...... your initial settings for re-learning to fly are fine. Mid stick at 5.5 and a low point of -2 or -3 degrees is totally fine. It will probably feel a little sluggish though and might not be as precise on the cyclic as it could be, but should be very managable. Any more negative pitch and you run the risk of just smashing it to peices if you cut the throttle in a moment of panic/confusion.
Your Tx will have plenty of options for the idle up switch, and when your comfortable you can program it to give a bigger pitch range, different throttle curve, and higher head speed. You'll then end up with +10 and -10 with 0 at mid stick. I wouldn't advise going all the way to start with though - maybe do an intermediate step say -6 to +10 until you get used to the more rapid descent rate. Again, your Tx will allow multiple flight modes so you can program in several idle up settings etc.
Your other option is to add a governor. Quite cheap, but something like the Aign will allow you to set up your head speed and then you can forget about the throttle travel on your engine as it will just take over and give a constant head speed.
just a last note - 1550rpm is quite slow, maybe aim for about 1700ish in normal mode and if you add an idle up throttle curve try 1850 for starters and work from there.

[Skipper Billy]

Thanks very much - a little more info. It hovers great at 5.5 degrees but only required just under 40% throttle - my question was - is this normal - it seems like it is.

The pitch curve on full throw gives me +11 and -10 - I have restricted it in 'normal' to -3 and +9 whilst I get used to it again.

The throttle curve is set 0 - 65% and seems to match the pitch curve quite well.

The comment about head speed makes sense - I will try knocking it up to 1700 ish and see how I get on.

I think I will also 'get modern' and try hovering at three quarters stick and stick a governor on it. After all - we seem quite happy to let electronics control the tail - why not the head speed as well???

Thanks for all your advice.

[RafeyRJX]

Sounds like a good plan. Once you add a gov' you'll find that when you switch to idle up (using your full pitch range -10 to +10) you will automatically be hovering at three quarters stick, with zero degrees at mid stick. - just remember to have a linear pitch curve set up in your Tx in idle up.
Personally, and this is totally your own preference i fly:
Normal flight condition -4 to plus 10 head speed 1750
Idle UP 1 = -6 to +10 hs 1900
Idle UP 2 = -12 to +12 hs 2100 and finally for autos Flight cond 4 which gives throttle to idle and -14 to +14

Now i know lots of pilots do it differently, i just move through my flight modes so i have the option of steady flight, sport, or just plain balls out. Also i dont get a huge jump from normal mode to my Idle Up 2 etc.
Well thats my two pence worth - im off to polish my shiny bits now.

[spunkmyer]

If you look at the pitch control arm the frame has ptich markings on it, a built in pitch gauge.

First make be sure that you have the tx throttle stick at the bottom position and also in the JR9 make sure your both your pitch,throttle curve is set to 0,25,50,75,100 in the tx then with the Throttle stick at 50% adjust the pitch link rod so that the pitch arm is on 50% mark on the frame.

Now move the throttle stick to 100% and see where the arm moves on the frame gauge then do the 0% position and again check the gauge on the frame. you can use this as you base them follow the advice above for advice setup.

[Skipper Billy]

Thanks everyone for your assistance.

In normal mode I now have 0 pitch at half stick, plus 10 at full stick, - 3 at bottom stick. Governor fitted (CSM RL20) and an enjoyable constant 1750 head speed - hovers beautifully - but hovering at 3/4 stick takes some getting used to!!!! Twitchy on pitch but I guess practice will smooth that out.

All I need to do now is figure out why the clutch is dragging - it wasnt before I had the engine out to fit the fan magnet!!

Thanks again.

David.