Too much headspeed on my raptor 30 v2

[Made2Fade]

Ade you seem to be the man on here at the moment... problem ive got is ive got too much headspeed when i bring the model into the hover. Both my needles on the TT39 pro engine are set really rich but im still getting massive headspeed at 3/4 stick. Ive tried setting the low speed needle so the engines so rich it just runs. The engine doesnt seem to over-heat so im guessing an airleak making it lean is out of the question. Theres plenty power its just theres too much headspeed like i say. Could my throttle be setup wrong or my pitch too low at hovering point? Ive tried reducing the throttle curve but it still does it. Any suggestions?
Cheers
Lee

[Ade_Law]

Thanks! :-)

Head speed is controlled by a marriage of 3 things.

Mixture, pitch and throttle

These days Collective Pitch is used to control the heli and shouldnt be used to control headspeed. So you set the pitch range to your ability. I wont go any deeper on this subject in this post its been covered a number of times. Any questions ask away :-)

in short keep the end point adjustment at 100%, zero sub trim, servo arm at 90degs to the pushrods at centre stick. Leave the pitch curve linear. Adjust your pitch range and centre point mechanically on the linkages.

Engine mixture is set to keep the engine happy again it shouldnt be used to control headspeed but headspeed can give clues as to the mixture. If all you are doing is hovering and gentle circuits then and engine that idles reliably and runs cool in the hover is a happy engine. The way I test temperature is fly the model for around 30 secs, land it and then put your finger on the backplate. On a 30 if it becomes painful in less than 6seconds its too lean. larger engines run cooler. Different engines act in different ways. its a bit of a balance between the 2 needles to get a reliable idle and get it cool in the hover most engines will interact a little between the needles.

So that leads us to the answer you have been looking for.

The throttle curve is the thing used to control the headspeed. But before you go rushing into the radio and messing with the curve you need to ensure that the throttle linkage is setup correctly. Just like the pitch, half throttle at mid stick, no sub trim and 100% end point (ATV). Should give you full throttle and throttle closed with the throttle trim pulled right back.

Now.. Start the model get it out on the flight line.

Bring the pitch up to 1/4 then by trial and error adjust the throttle curve for the 1/4 point until the headspeed is a little below the required.

Now being aware that the model could take off (depending on your pitch setup) bring the stick up to 1/2 and do the same but now you are aiming for a "flying" headspeed.

then the same for 3/4 you will have to do this by landing, adjusting and having another go as you will be in the air this time.

Finally check the full pitch climb out. Make sure that the headspeed doesnt increase or decrease excessively.

hope this is clear. Its easy done than explained :-)

Ade

[Made2Fade]

Thanks for that Ade... ive been fiddling with my throttle curve. Problem is that i can put the curve to lets say 35-40 at mid stick and the headspeed is still massive? Im using the futaba ff9 by the way. Does this mean that my throttle link is adjusted wrong or something?
Thanks
Lee

[Ade_Law]

quite possibly.

lets start with your pitch curve, how do you have it setup and how do you describe your flying at the moment?

I need to know ATV values, Sub trim and pitch curve values.

Ade

[Made2Fade]

Flying at the moment is figure eights stage and practising nose in at a good height for safety. Ive put my throttle curve back to linear as i was having no joy messing about with it. My pitch curve is:- 35,48.5,64.5,82.5,100 in normal flight and again linear in idleup1 as ive never messed with it yet. My subtrim is 0/0 for everything. ATV is 140/140 for pitch and 100/100 for throttle.
Cheers
Lee

[Ade_Law]

that pitch curve isnt quite linear. I prefer to leave the pitch curve 0,25,50,75,100 and do range/mid stick pitch adjustment mechanically. Your pitch ATV is very high, you could probably use coming out a hole or 2 on the servo horn.

At the level your at, your thinking about going into circuits so its time to think about opening the pitch curve up some to give you proper height control. A common complaint of people starting to do circuits is that they cant make the model come down without loosing the power. This isnt due to not using idleup its due to not having enough negative pitch.

Reset the pitch curve setup to 0,25,50,75,100 and atv back to 100. then start at mid stick on the pitch and go up through the linkages getting everything at 90degs and level, to give 0degs pitch. Then by changing the position of the ball on the collective servo horn you can adjust your pitch range to give a good climb out.

Reset the throttle curve as I described earlier. If you pull the link off of the throttle servo it allows you to check for binding.

Ade

[phil485]

Learning a lot on this thread!
Similar level and similar problems.

would you suggest -9 or -3 for someone at this level Ade.
If -3 and the linkages allow for the full -9 to +9 should you do it then say use the lower end ATV to limit the travel, or adjust the pitch curve?

[phil485]

Probably missunderstanding ( ops: ) but you said, at mid stick to make the pitch 0, but I thought you would need + for hovering at mid stick

ops: ops: ops:

[Ade_Law]

Mid stick hovering stems from the old days.

I am against hovering at "a" position. Keep it linear and the model will react the same to stick inputs no matter what you are doing.

A rather extreme example is Mid stick hover with a the full -9 to +9 pitch range.

for arguments sake lets say the heli hovers at 5degs of pitch. So from mid stick to full pitch you have a range of 4 degrees and from mid stick to full back you have a massive 13 degrees.

This will make control of accending and decesending very different as the sensitivity will change depending if you are above or below hover.

consistant feel is the key to helicopter flying.

Ade

[Ade_Law]

Assuming you are learning on training undercarridge to start with you want about 0 at full back stick and about 8 at the top, This reduces the chance of you slamming it in the ground when you pannick and shut the pitch/throttle.

Once you are comfortable on the Training UC hovering, get them off and then get used to how the heli feels.

Then you want to be looking to extend the bottom end of the pitch range. I prefer to do this mechanically on the linkages so the radio setup stays at default values. The servo should always be at 90degs to the pushrods at mid stick then the linkages above that are adjusted to give the range that you want.

I like to see my trainees get to the full range from there before going into circuits, this means you dont have to relearn the feel of the helicopter further down the line. Do it over a couple of steps so -4, -7 then finally -9. If you setup the linkages for -9 then used the ATV to reduce this would give you a very nonlinear action as atv doesnt affect the mid point.

Ade

[phil485]

Brilliant, the mud is starting to clear.

[Made2Fade]

Ade so basically if i leave everything linear in normal and idleup1 then set the heli up to get -9,0,+9 on the pitch. All the linkages being 90 degrees at mid stick for both pitch and throttle, all atvs to 100 either side and 0 sub trim then the model will behave correctly and in the manner that you advise?
Lee

[Made2Fade]

Then once that is done i can use the pitch curve to limit my bottom end on the pitch for normal flight mode. When i do that how shall i be compensating also with the throttle curve?
Lee

[Janek]

Made2Fade,

I'll jump in here with a little advice.


Keep ALL your pitch curves identical, in all flight modes.

I've seen too many near misses when someone "test" flys another heli, and there is a pitch jump between Normal and Idle up, and the owners has forgotten to warn the flyer 8O .

If you're really for the transfer to a full 3D pitch curve, go for it completely, don't mess about

[Ade_Law]

i hate that phrase "3d curve"

problem with that is people immediately jump in and say "i don't/will not be doing 3d"

Its not a 3d curve its a pitch range that allows you to put the model exactly where you want it with minimal switch flicking and minimal risk of being in the wrong flight mode.

Aggreed on the same curve for all modes. How many crashes/near crashes have you seen due to not having the full range available in (normally) idle up 1 and flipping inverted? I will tell ya, non recently because all my guys use the same curve in all modes :-)

its the KISS principal. the less switchs there are that need to be in a certain position the less likely hood there is of being in the wrong one :-)

Ade