Radio Set up....

[Steve Hargreaves - Moderator]

I used to fly helicopter back in t' olden days & I recently came across my Excel 60 in the loft.....Nostalgia being what it is I started wondering about putting it back in the air.

 

I understand that helicopter RC set ups have changed a bit these days. I used to have about -1 pitch & the engine at idle with the throttle stick right back. Mid stick would hover & full throttle was just that. My set used to have an "invert switch" too so if you went inverted you would flick the switch & this would effectively reverse the collective, forward/back Cyclic & the tail rotor controls so that the controls worked in exactly the same sense upside down as the right way up......

 

As I understand it the "modern" way is to have full negative pitch at idle with zero pitch at around mid stick so the model will probably hover at about 2/3rd to 3/4 movement of the collective....is this correct?

 

Any pointers on how to set up a heli would be much appreciated!!

[Former Member]

[This posting has been removed]

[Dave Bran]

Set up "a" heli or your Excel??

 

Yes, broadly what you say is right, however, the way a "modern" heli is set up is based on the head of that heli's ability in as far as the range of angular movement available.

 

For example, the Hirobo Sceadu has a more limited range than the Sceadu EVO. It notices!! To get sufficient negative on an old design head for more than extremely rudimentary "3D" can be a challenge! And 3D is not the only limiting issue, remember, without negative pitch it can be difficult to descend, ask any MM Lark owner.............

[David Gilder]

Steve.

 

Normal set up these days is -1 - +8 or 10 pitch with linear throttle curve from idle to 100% for normal flying.

(-1 pitch at idle throttle and + 8 to +10 pitch at full throttle)

 

Then when in Idle Up mode (3d and inverted flight) mid stick = zero throttle (set to approx 80% power). Stick in full throttle position is 90 -100 % throttle with full posotive pitch and thrttle stick at bottom is same throttle setting with full negative pitch.

 

Hope that makes sense!!

 

Dave

 

 

[Steve Hargreaves - Moderator]

@ Dave Bran.....I think the MM Lark was a fixed pitch head so yes you are right the only way to get it down was to let the head speed drop right off & then hope it picked up again before you ran out of height.......the Excel 60 was a pretty hot ship in its day & was fully aerobatic.....I doubt it would do well in 3D without a bigger engine (OS61 in mine) as it is quite heavy....plus the pilot will need seriously upgrading too.........it has a pitch range of around 20 degrees if I recall.

 

@ David Glider...thanks David you confirmed what I thought.....so the throttle curve in idle up is a sort of U shape then? Your normal flying set up sounds pretty similar to what I used to use......bit of a tweak of pitch & throttle curves around the hover setting to get head speed & revs comfortable.....

[David Gilder]

Thats it Steve

The throttle curve in idle up is more of a V than a U!!

 

Cant wait to hear how you get on!!

 

Dave

 

[Steve Hargreaves - Moderator]

Thanks David...don't hold your breath....it might take a while to get everything sorted....

 

I've just ordered a new Gyro to replace my old Morley unit......apparently they are solid state now & don't have a spining weight inside them.....Corrr what will they think of next!!!

[Ed Darter]

new gyro - you'll be needing to get your head round remote gain etc on the tx as well then! its moved on quite a bit Steve!!

 

Good luck, its al good fun

 

Ed

Edited By Ed Darter on 14/10/2011 21:42:25

[John Privett]

...not to mention "heading hold"

 

[Steve Hargreaves - Moderator]

"Heading hold"...is that when you put your head in your hands after you've crashed again???

[John Privett]

Well that's certainly one use of the term Steve!

[Steve Hargreaves - Moderator]

Just resurrecting this thread again in another box I found my old Concept 32.....sans blades....It all looks pretty servicable so I was thinking about getting this one in the air too.

 

But where to get blades...? I see lots of Fg & CF blades around but none appear to be the right size. My concept blades were 500mm long. I can find 600mm for "600" class machines & 430mm for "500" class but I need something in the middle of that....any ideas....

 

Also Gyros......I spotted this & thought it was worth a punt at $12...but it seems a bit odd in its operation to me.....what is AVCS in English? & also it seems very sensitive....the servo responds to the slightest movement of the gyro...maybe thats good....I used to use the Quest gyros....they had a spinning flywheel in them to act as the gyro so pretty old technology.

 

Also when I connect up a servo to the gyro & move the rudder stick the servo tracks fine but then stops before the Tx stick has reached the end of its movement.....is this correct or have I just bought a cheap (& rubbish) gyro??

 

All thoughts greatfully received............

 

 

[Pete B]

I'm still learning myself, Steve, albeit very slowly........

 

I have a couple of giros like that and, whilst they won't reach the performance of a £100 giro, they're good enough for most basic purposes. Available in many coats, too, even in the UK.

 

AVCS is 'heading hold', as mentioned above. At its simplest, giros can be operated in two ways, rate and heading hold. Rate is where the giro will keep the heli stable about the rotational axis but the tail will 'weathercock', whether by the wind direction or by the forward motion of the heli.

 

Heading hold is where the giro stabilises its heading, relative to the ground, and will stay on that heading until a rudder command alters the heading.

 

In the broadest terms, scale helis fly better on rate and 3D types on heading hold.

 

The giro is normally set up on the Gear channel. A value up to 50% will give rate mode and above 50% heading hold. You use the gear switch to move from one to the other.

 

I'd recommend Finless Bob's instructional videos which are first class. Plenty there on giros etc

 

You heli boys go easy on me if I've misinformed Steve in any way - I'm typing most of this from memory!

Pete

[Dave Bran]

Blades:-

 

BBT 'MANIAC' 503MM 3D CFK BLADES

 

and others, even 437's if your engine might be tired...............

[Dave Bran]

Posted by Steve Hargreaves on 08/11/2011 16:42:57:

Also when I connect up a servo to the gyro & move the rudder stick the servo tracks fine but then stops before the Tx stick has reached the end of its movement.....is this correct or have I just bought a cheap (& rubbish) gyro??

 

All thoughts greatfully received............

 

 

The amount of tail movement is a function of the servo horn length (usually low, 13mm for a 50 is "norm", and the LIMIT setting on the Gyro.....you do not set the rudder end of travel by the trim and/or EPA(Travel Adjust) settings on the Tx.

 

The sensitivity process will depend on the Tx gyro "type" setting as well as HH or Rate percentages, and for make of Tx. What are you using?

[Steve Hargreaves - Moderator]

@ Pete B...thanks Pete...I've added that page to my favorites for a good viewing later...

 

@ Dave Bran....thanks for the link.....those blades look a bit hi tech (read: expensive) for what I'm trying to do.....I've been looking for some cheap FG blades.....lots on the HobbyKing website at around $20 plus postage. I only want to get the thing in the air for a bit of a nostalgic hover.....I won't be 3D ing it anytime soon!!!!

 

The radio I'm using is a Futaba 10C & thats a good point actually I didn't actually use a heli setting.....I just plugged the gyro into channel 4 on a spare Rx & used whatever model was in the memory......a Wot 4 I think....so none of the heli stuff in the Tx was active....

 

Maybe I need to try that bit again.....

 

Thanks for the tips chaps!!!

[Ed Darter]

definately get the TX set to heli mode, it will be so much easier to set up throttle and pitch curves etc if you do.

You have probably sussed it already, but just in case....to clarify Pete B's point the gyro plugs in to the rudder channel, its the gyro gain lead that plugs into the gear channel (usually)

Also, as Dave mentions, don't set the physical travel amount via the TX, that should be done mechanically by choosing the right hole in the servo arm or via the gyro (I think that HK one has the end point adjustment feature). Setting the end points in the TX just adjusts the pirouette rate of the model ! May be useful if you feel the tail is a bit lively, but it will not stop the tail pitch slider binding.

 

Last thing from me - don't scrimp when it comes to blades, generally they are cheap for a reason and I know of at least one failure (albeit on a 450 sized model) where cheap blades were to blame, turned out there was very little material holding them all together near the root, trouble is you can't see that until after they have let go!

 

hth
Ed

[Steve Hargreaves - Moderator]

Thanks Ed.....good advise...

 

Don't worry I wasn't going to try & fly the heli on anything other than a heli program.....I was just having a little play.

 

I've had a play with the gain thing & set it to the centre VRB dial on the front of the 10C (I'm guessing I will be using VRA & VRC for hovering pitch & hovering throttle trim) & it seemed to work OK.....turned to the left it reduced the sensitivity...from centre to the right the AVCS light came on.... I think that seems to be correct....