Throttle Jockey and new blades?

[belair]

What can I gane with the use of a Throttle Jockey on my heli? When do you need one for flying? Also will my heli fly better with composite blades than the original wood blades? Hope someone can give me a answer. :lol:

[antsis]

The whole idea of a throttle jockey is to keep the headspeed constant at all pitch settings. Obviously this has to be sent up initially, but once active it pretty much controls the throttle automatically. Most pilots will have it activate from a specific stick position.

Composite blades are less likely to flex and give the model more stability. However, if you're learning to fly, I would stick with the wooden blades. They are much cheaper to replace.

[belair]

Hi Ant,
I'm in the stage of being able to fly of and get the heli back in again, the figures of 8 I am begining to master and on the sim on my computer I can hover nose in. So like you say the wood blades would be better until I fly a little better. As for the throtlle jockey, I can set my throttle to a sertain speed from my transmitter, with the pitch curve the whole way, so maybe I should wait some more before buying expensive bits like that.
Thanks again ant,
Belair

[Raptorite]

Hi Belair,

I agree with Antsis, the purpose of a governor is to keep the head speed consistent throughout the whole flight. As with the powerful engines around today, descending the model from something like a circuit would normally cause the model to over speed, as in the rotors are turning too quickly. This happens because the throttle curves are set such that there is enough power to drive the blades when in the hover or climbing. Whereas when the model is descending, there is little or no load on the rotor disk therefore the engine is providing too much power to the rotor head.

A governor gets round this problem by continually sensing the speed of the rotor head, or in most cases the fan, which is then calculated to rotor head speed using a gear ratio which is entered when setting the governor up. When it detects a fluctuation in the rotor speed, it increases or decreases the throttle to compensate, therefore as in the descent example the governor would sense the rotor head speed increasing beyond its set speed and decrease the throttle in order to maintain that constant head speed.

On the whole, governors are a useful piece of kit, but only really come into their own when you start doing aerobatics, in which case the governor will be almost continually adjusting the throttle to compensate for the different loads on the rotor disk associated with aerobatic manoeuvres.

In your case where you are hovering and flying circuits, it is not necessary to have a governor as a well setup normal mode and idle up 1 throttle curve will do just as well. Having a governor is also adding to the potential expense of repair bills, should the unthinkable happen as they are prone to impact damage.

On the subject of blades, yes, the carbon fibre ones are torsionally stiffer, which means the model will feel more stable in the hover and maybe track a little better in forward flight, however, the benefits are not great enough in my view at this stage of the game to justify the extra expense of replacing them.

I hope this helps.

Cheers,

Pete.

[belair]

Hi Pete, :idea:
That is a lot of reading, thanks for the info. So if I set my idle up1 with a constant throttle ( head speed ) that will do for me? Or will I not need a constant speed for the flying I am doing? When I desend after giving negative pitch I have to give my heli a positive pitch and also more engine power so that it doesn't smack in the ground or how is it normaly done? You see I had to lurn everything by my self, so it makes my flying a little harder. :?
Cheers
Belair

[Raptorite]

Hi Belair,

Yes, in essence, as long as you have an idle up 1 throttle curve with assuming you have 5 point curves on your transmitter, you need the first two points set the same as hovering throttle (normally point 3) as a basis, then test fly and tweak it from there.

In the example you mentioned where you are descending the model by using either low pitch values or negative pitch, you need the idle up 1 throttle curve to have around hovering throttle at those low stick positions in order to maintain a consistent head speed so there is enough energy in the rotor disk for it not to load up when you feed in the positive pitch to stop the descent at the bottom and stop the model bitting the dirt.

Then you will obviously need the normal throttle curve to be able to land the model and spool down safely at the end of the flight. The best way to swtich between the two modes is to do so when the model is hovering, so when you spool up and bring the model up into the hover in normal mode, before you move off into forward flight, engage idle up 1. Conversely when you bring the model back into the hover from forward flight, disengage idle up 1 whilst the model is hovering, then land and spool down.

One thing to be careful of though, is to make sure you have the hovering points of the pitch curve exactly the same in both modes, as if not the model will jump either up or down when you swap between the two.

Cheers,

Pete.

[belair]

Hi Pete,
Thanks again for the explenation, I regret that you don't live in Belgium. We need people like you over here. In my club there was one member that was going to help me out with the radio installation on my heli. At the end I had to do it all by myself, best way of lurning your radio setup, and it looks like I know more of the basic stuff than he does. And that by just talking to people like yourself and reading articles in the Rotorworld magazine I subscribed to and looking up things on the net.
My last question,would I be better to make the expense of buying a new radio with a 5 point pitch and throttle curve, my radio does only do 3 point. It's a Graupner MC12, I bet you never seen one of these. They sell them more in Belgium, Holland, France and Germany. Have a look in my gallery.
Cheers
Luc - Belair

[belair]

Pete, what do you think of the new JR 2610 and the Sanwa sport or super?
Luc

[Raptorite]

Hi Luc,

Its a shame, as if you had asked me 2 or 3 years ago about being in Belgium, I would have said that I spend at least 3 days a week, every 2 weeks in Brussels. As at the time I was busy travelling round Europe converting many different business and accounting computer systems to the euro currency. I used to have lots of meetings with the European Commission, which is why I was in Brussels allot.

You are right, I dont know much about the MC12, other than that it is I believe Futaba based. The 3 point curves will be fine for basic hovering and circuits, but is unfortunately a little cumbersome for anything much beyond that. In the longer term you will definitely find it easier having a transmitter more suited to heli usage with 5 point curves.

If in the long term you are looking to upgrade your transmitter, I would suggest that you look at ones with 8 or 9 channels, as Im sure you will find a use for the extra channels latter on when you get into using things like governors etc. where those extra channels will come in really useful.

In the mean time though as long as you have points 1 and 2 in the idle up 1 throttle curve set to be around 50% throttle, or what ever % your model needs to hover, you will be fine.

Cheers,

Pete.

[belair]

Hi Pete,
Thanks again, I think I'll wait with another radio untill I pas the hovering and cirquit flying. I'll get better by the end of the next summer, in the winter I can take the time of setting up my radio. I was looking in my manual last night and now I understand the idle up term, in idle up you don't have a idle setting, do you. I'll set my idle up in the way that when I have the hover I can switch over without it shooting up or whatever. But do I have to set the pitch in the same way that it is as in hovermode. Otherwise the heli would shoot up ore fall down when I switch over.
I'm getting there Pete.
Untill your next message.
Belair signing off.
Luc

[Raptorite]

Hi Luc,

Yes, you are almost there, Idle Up is the term used to describe different flight modes defined in the transmitter. These flight modes are normally used to change the throttle and sometimes pitch settings for different styles of flying.

The most common use of idle ups is to set different amount of throttle used at different stick positions, so for example in normal mode you will have 0% throttle, or tick over at bottom stick, in Idle Up 1 you will have around 50% throttle at bottom stick, mainly for flying circuits, loops and rolls etc. Idle Up 2 will then have 100% throttle at bottom stick, which will also have around -9 or -10 degrees of pitch to allow for inverted flight and to have the power to climb out while inverted.

As you rightly say, the hovering pitch needs to be set the same in all modes so that when you switch between them, you dont suddenly get more or less pitch which will cause the model to climb or fall sharply.

In your case, where you have 3 point curves, I would, assuming the pitch is set mechanically to be -10, 0, +10 at full throws, have the following pitch curves;

Normal 35% 50% 100%
Idle Up 1 35% 50% 100%
Idle Up 2 0% 50% 100%
Hold 0% 50% 100%

These curves will give you, firstly the same middle position, so that when you switch between them when you are hovering, the model wont suddenly jump up or down, and secondly, both normal and Idle Up 1 have point 1 set to 35%, which should in this instance be about -4 degrees of pitch on the blades, you wont have too much negative pitch when the model is on the ground, so not causing it to try and drive itself into the ground as you spool up or if you forget to disengage Idle Up 1 when you land.

The throttle, which assuming your model hovers with a nice head speed at 50% throttle, would look something like this;

Normal 0% 50% 100%
Idle Up 1 50% 50% 100%
Idle Up 2 100% 50% 100%

These throttle curves would give you the ability in Idle Up 1 to fly circuits and descend the model back down to a hover, while maintaining a consistent head speed, and Idle Up 2 will give you the throttle needed to sustain inverted flight.

For the time being, I wouldnt setup Idle Up 2 until you are ready for it, as if you engage it by accident while you are on the ground or hovering the model will obviously go to 100% throttle, which could be quite dangerous if you are not expecting it.

Cheers,

Pete.

[belair]

Hi Pete,
You should take up a new job, teaching us beginners to fly and setting up radio gear. After reading your comment I get the picture a little better now. The only problem is that I don't have a Idle up2, now this isn't a problem for the moment because I don't need one for now. As I sayd urlier I think about getting one next winter. I can use all of the functions on my MC12 for the flying I do at the moment. I have a few days holiday coming up and I'll try to get my radio setup like you say it should be. I'll let you know how I get on. That is if the weather is good for flying.
Thanks again Pete,
Cheers
Luc