eheheh

Hi all,

anyone know if there is a stand-alone mixer board on the market that could mix main and tail signals?

Seems to be the missing link with the separates setups.

Most people seem to just let the HH gyro battle the torque to keep things straight and have the tail signal left mid way throughout all the throttle settings. Mixing on the tx is out of the question on the HH gyros so the only logical solution is to mix the throttle and gyro output signals and feed this into the tail ESC.

Anyone got a solution for this?

Perfect setup would to be able to measure the main rotor rpm and use this is the reference to mix with the gyro output to drive the tail ESC levels. Remove lag mixing issues that way.

Oi! GWS! there's an idea for the PHA-02! (oh, and throw in some sensible heat sinks)


Also, I noticed that there is a "Humming Board" that I assume the Hummingbird heli uses. Is this just a mixer or is it a combo ESC mixer for main and tail?

marked23

Most people go separates because they want to use a brushless motor. I haven't seen a brushless main / brushed tail mixer board anywhere.

Using a HH gyro without any mixing at all is totally normal. This is how it is done on the nitro helis too. HH gyros are really "set it and forget it."

If you use a HH gyro, stop looking for a mixer. You shouldn't use one. If you have a rate gyro, you can do your mixing on your radio... presuming your radio has multi-point mixng curves.

BTW, My hummingboard seemed to do a better job of mixing than I could do with my radio. However, that may just my programming.

-Mark

eheheh

Yes but on nitro heli's the tail speed is directly proportional to the main rotor speed due to a mechanical link between the two. No mixer needed on board.

And no, you cannot do main to tail mixing on your transmitter if you have any form of Gyro in your heli as the signal to the gyro will change every time you apply a change to the throttle channel. Every time a gyro senses a change on it's input signal is eases off on trying to correct which leads to odd behaviour on the yaw (wagging most of the time).

The mixing on Heli Tx's deals with Throttle to Pitch mixes on CP models and Revo mixing which applys small changes to the tail pitch on heli's that use a mechanical link to the tail rotor from the main motor. The Revo mix corrects the torque changes when the pitch of the main blades are changed. Heli setups on TX's are not designed to work with heli's that use a separate electric motor for the tail.

Hence the advice from most dealers that you should use a standard aero Tx for these types of heli's.

With electric heli's that use a separate motor for the tail the removal of the mixer throws all rotational ratio's out the window.

I'm not saying that the heading hold gyro cannot do the job at all without a mixer. I'm saying that to get it to work you are setting it up to counter torque outside of where you decide to set the yaw channel when it is centered. The yaw channel in the mixless setup remains in one position the whole time unless you apply a forced change on the transmitter. With this setup you have to get the yaw channel set to a position as close as possible to having the tail straight in a hover and any variances in your flight behavior which fall outside of this balance will cause yaw due to torque will ends up getting tackled by the gyro. Add to the fact that the tail will be running when you have no throttle input and you have to set the yaw input on the Tx to zero for a couple of seconds to allow the tail ESC to initialize.

The mixless setup with HH is like flying a heli with a constant blast of wind on the tail. The gyro will be constantly battling to keep a heading when you move into anything other than a stable hover.

For the sake of the exercise I will be getting a GY240 HH gyro this week and I will be hooking up two separate ESC's. Initially there will be no mixer. All behavior of the heli will be documented in this configuration. Then to compare I will go back to the PHA-01 (2 ESC's/Mixer/Gyro), set the gyro gain to it's lowest, hook up the GY240 between the PHA-01 and the yaw channel on the Rx and document the heli's behavior with this configuration.

Now if I had one of these new CyberCopter's which function the same way as the nitro heli's mechanically (main-tail direct drive link) then a HH would be one very happy camper.

Hey, somebody has to explore this configuration as I don't think it's been investigated so far from what I have been reading.

Guess the proof is in the pudding...we'll see what works the best with the real thing rather than just theory.

marked23

Hmm.. Ok.

So what you are saying is that this could improve tail stability with a HH gyro?

What if it's already perfect, with just separates and a HH gyro. Then why bother? The gy240 will hold great, mixer or not.

-Mark

eheheh

Hi Mark,

can you please confirm the following:

A) your heli uses a separate electric motor for the tail.

B) you are using two separate ESC's and a GY240 connected between the yaw channel cable from the Rx to the tail ESC.

C) you have not set up any mixing of any sort on the Tx.

D) the tail remains in exactly the same spot from standing still on the ground, to hover and then during forward flight when you are not applying any deliberate yaw.

E) when you do apply input to the yaw channel the heli rotates cleanly and sharply without any wobble in either direction.

If these are rock solid facts for all points then I'll stick my theory on the mixing issue in the bin and not give it another thought.

Regards,

John

Mhale71

uh oh, i have an ep concept sr, that flys well, i also have a gws dragonfly that just needs electronics, i thought the pha-01 whas for this?

eheheh

Fear not say I! The PHA-01 is fine if you have a few weeks heli experience behind you. It's just a bit of a bugger to find a balance on the mix setting so that the impact of heat build up is not as noticable in the first 5 minutes after the electrics are cold. I actually completely removed the dicky plastic cover off the board on the weekend and that has reduced the drift in the mix substantially. Just stuck the double sided tape directly to the large IC on the back.

I'm yet to prove that if you introduce a heading hold gyro between the yaw channel on the Rx and the PHA-01 with it's own gyro sensitivity all the way down that you get the tail perfectly straight under all flight conditions.

Stay tuned.

marked23

I've been working on building a good separates setup for about a month now. I finally came up with something that is suitable for use, yesterday. My main mistake was using the wrong tail ESC. From reading other posts, the GWS ICS-50 and CC Pixie-7p are both good. I use the GWS ICS-50.

A. Yes
B. Yes, Two separate ESCs. One is brushless, the other is brushed. Gyro is CSM HLG200. Fut gy240 should be equivalent or better. Your choice of tail ESC matters a lot.
C. Yes, No mixing in the radio... HH gyro will not tolerate it.
D. Long answer:
Exactly? No. But I haven't tuned my gyro gain yet. [I've flown just one battery on current setup.] It might. At my current gyro gain setting (about middle) I get a bit of torque induced drift during a sharp (very sharp) climb out. It drifts 20deg and then sticks right there. Perfect? no. Useable? Totally. I think a bit of fine tuning on the gyro gain can cure this. Nominal climbouts are perfect. There is one single wag (30deg) when the heli leaves the ground, as the gyro spins up the tail motor. In forward flight it is rock solid. In turns, it's solid. There is absolutely none of that spinning around business even on full power launches.
E. Yes. I can do fast or slow piros in both directions. When I center the stick, the tail stops... always. Sideways, forward, backward flying.

Here's my full setup: (copied from another post)
[link=http://www.heli-world.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=H&Product_Code=CN1020A]Hummingbird v.II[/link]
[link=http://www.hobbyhorse.com/eflite.shtml]eFlite Park 370 Brushless[/link]
[link=http://www.castlecreations.com/products/airplane/brushless/phoenix-10.html]Phoenix-10 Brushless ESC[/link]
[link=http://www.gws.com.tw/english/product/MOTOR/MOTOR.HTM]GWS direct drive tail motor (CN12-R-??)[/link]
[link=http://www.gws.com.tw/english/product/speed%20controller/50.htm]GWS ICS-50 tail ESC[/link]
[link=http://www.gws.com.tw/english/product/propeller/propeller.htm]GWS 3020 tail prop[/link]
[link=http://www.helihobby.com/html/gyros.html]CSM HLG200 gyro[/link] (yes, the gigantic blue one. I'm going to lighten it... It's way huge!)
[link=http://www.thunderpower-batteries.com/html/batteries.html]Thunder Power TP1320-2SJ 2-cell Lipo[/link]

That being said, I still wonder if a mixer would be helpful.

-Mark

eheheh

Yes, I read a number of posts saying the Pixie 7P was the go for the tail .... that's what should be turning up at my front door tomorrow.

It certainly sounds like the HH gyro's can tackle quite a bit of the issues of not having a matched main to tail rpm ratio from your own experiences but as you said in point D it's not 100% perfect with the inital swing of 20 or 30 deg. The PHA-01 and GY240 combo test will act as a performance test/comparison. If I'm lucky and find that it is as stable as the setup you are using but without the inital swing of the tail then I might be onto something here.

If that looks promising then I might sit down and come up with a circuit diagram that can mix two Rx signals at 5 different points (for added accuracy). And while I'm at it I may as well look at using a pulsed input from a sensor that can measure the RPM of the main rotor and use that as the guide for determining the tail signal levels. With this little board it could be used with separate quality ESC's to fairly much simulate having an actual mechanical drive connection to the main rotor like most heli's use.

Eh, who knows, GWS (or someone else) might very well come out with a far better all-in-one board some day soon that can deal with all this.

Jerrykl720

http://www.zebrahobby.ca/cgi-bin/cp-...eliElectronics

eheheh

I assume the FD-042 is the dual ESC/mixer board that originally shipped with the DF heli when you had the separate PG03 gyro.

Preferably a mixer that has no ESC's would be good for people who have gone out and obtained good quality separate ESC's. Unfortunately I don't think they exist.

thiswillfly

I went seperates on my stock aerohawk using a CSM HH gyro and have been dissapointed with the results. With the absence of any tail mixing the tail is constantly fighting the main torque and is noticeable with tail wagging. Have tried all gain settings and the gyro is mounted correctly. I'm using a pixie 7p main and GWS 100E tail.

My theory had suggested this would happen but had hoped it would be ok in practice - wrong!. HH gyro's work well on nitro heli's 'cause the tail drive is fed from the main drive and is therefore the equivalent to electronic mixing. HH gyros are designed to remember and keep the nose pointing on a set heading - they do this by detecting and reacting to movement exactly like a standard rate gyro does - hence the same sort of problems if there is no mixing.

Fortuantly there is an answer to this - but more money!. (I'm still trying to swallow cost of HH gyro at moment). That is to use a TREC ESC which mixes throttle to the tail motor and is fully programmable with gain and throttle curves etc. Cost is about $60 but this will sort the problem and the tail will be under full control as it should be. Will be getting one of these when I can.

marked23

Try swapping your ESCs. Put the Pixie on the tail. Try it with the throttle self calibration both on and off.

What tail motor and prop are you using?

-Mark

eheheh

I just purchased the full TREC ESC kit direct from Dionysus Design!

This is very much the thing I've been after here.

This should do away with any gyro issues and allow me to use any ESC / motor type for the main motor.

[link=http://www.dionysusdesign.com]www.dionysusdesign.com[/link]

Note the "Glitch Reducer" on the main page. Sounds like something like that would cure the 7P issue I mentioned.

eheheh

thiswillfly - it seems your theory on the matter is in sync with mine.

You do hear flyers out there who have managed to get it to work without a mixer to some degree but the one thing you see happening even if they can control the wag is that you can hear the tail motor oscillating the power levels up and down constantly.

There is a video in here somewhere where someone is using a mixless setup and a HH gyro and you can hear the tail motor going fast-slow-fast-slow even though the tail is not moving. It's much like a controlled oscillation where the constant up-down speed changes in the tail motor are in balance with the tail mass momentum. By the time the motor is about the move the tail left the gyro has already slowed down again before the tail had a chance to move. It probably is moving back and forth but only so slightly that you don't notice it.

My hope is that with the mixer back in the picture you will have no issues with setting the gain as low as you like on the HH gyro. That way if something does bump the tail out of direction the gyro will ease the tail back without any battle on the torque. Add to the fact that the heli will be able to yaw a lot faster.

The guys at Dionysus Design should give a write up on why they came up with the TREC. Would be interesting to see if their theory is close to what we are saying.

ChopperMike

Exactly right. With a HH gyro you don't need or want any mixing. With a rate gyro you use the Revo mixing. If you don't have a heli radio then you have no choice but to use a HH gyro. Some older heli radios only have 2 adjustments for Revo mix, high and low stick. This makes it more difficult to get it just right. On my 9C I have 5 adjustment points and can get my HB to fly w/o wagging.

Mike

eheheh

Hi ChopperMike,

what's you current heli setup? (model, ESC's, gyro etc.)

ChopperMike

Setup is:

Hummingbird FP, Futaba 9C, GWS 4ch RX, GWS ESC's for main and tail, MPI gyro, Thunder Power 1320 mah 3 cell, stock motors.

Mike

eheheh

Is the HPI gyro heading hold or just a rate gyro?

Did a search on the net and couldn't find any references to this gyro. I'm sure it exists but there doesn't seem to be any write up's on the net about it.

If it is only a rate gyro are you doing any mixing on your heli Tx?

ChopperMike

The Gyro is an MPI PG2033. I believe it is similar (same?) to the micro gyros the GWS sells. It is a single rate gyro.

Yes, without using a HH gyro you need to enable REVO mixing on your TX. With the 9C you have 5 separate points you can adjust. You just adjust each one until you can move the stick up or down w/o too much swing.

Mike

eheheh

Just to clarify your statement on HH Gyro's:

You do not need or want mixing to be fed into the signal that a HH gyro is linked to on the Rx as this will throw out the calibration. When a heading hold gyro is first powered up it looks at the position of the yaw signal and uses this as the reference for when it needs to hold the heli's direction. Any variation outside of this normal yaw position (center stick for example) is considered to be a request to change the heading of the heli.

Whereas, and I think this is the point that most people are missing, any mixing done on the signal that comes out of the HH gyro on board the heli has no effect on this reference position of the yaw channel coming out of the Rx being fed into the gyro.

With some careful setup of an onboard mixer to ensure a stable tail in the first place the introduction of a HH Gyro, after this is done, between that yaw Rx channel and the mixer board just adds the next level of stability where the tail won't move at all unless you tell it to.

Do this and it will be like flying a 'normal' tail driven heli with a HH gyro.

Gyro designers aren't thinking about heli's that use a separate motor for the tail, they are thinking about the way most normal heli's work with the way the tail rotation is driven directly from the main rotor. Sticking a HH gyro in these micro heli's without a mixer is like sticking a HH gyro on a poorly set up nitro heli. Sure it will work but the poor thing will be working it's butt off to keep the heli straight.

As an example, if you reef out the hh gyro so you are back to just two ESC and no on board mixer, try keeping the tail perfectly straight via input on the Tx. No easy task. Whereas, if you put an on-board mixer into the equation and set it up to generally deal with the changes in torque then you will most likely find it far easier to keep that tail perfectly straight yourself during flight.

The HH gyro is like an on-board pilot. Make it's job easier and you will see an improvement on what you already have.

Some obvious improvements that I can see:

1) tail wont be rotating while the throttle is zero.
2) won't need to move the stick to the full left position to initialize the ESC.
3) you won't have any initial swing of the tail when you take off.
4) the likelihood of tail oscillation is greatly reduced.
5) the gyro's holding ability will be greatly increased due to the fact that the bulk of the torque is already being compensated for by the on-board mixer.

I'm in the throws of doing some extensive testing with this so expect to hear more on the subject in the next few weeks.

I'm hoping the TREC board with it's PC interface and customisable gain/throttle curve will give me the best mix setup I can get without even introducing the gyro to the equation.

The HH gyro will be the icing on the cake to total tail stability.

Campbell Grant

Please can you help me?



I have a Hummingbird CP Elite and I am using a CSM 200 HLG with Phx 10 and TREC esc's and GWS EDPS 50 DD tail motor.


a) When the 3 to 4 pin adapter is connected between the main esc and the receiver, and the yellow auxiliary input wire is connected, does Mixing have to be enabled? And, if Mixing is disabled, must the yellow wire be disconnected.


b) In order to disable one of the BEC's, I have cut the middle servo lead on the TREC, i.e. I have only the two outer wires going to the gyro. Is this OK?.


c) Am I correct in thinking that you do not need the mixing enabled? But, can it be beneficial to use mixing with a HH gyro.


d) In the instructions, under Advanced Gyro Settings, it details that you can use the 3 to 4 pin adapter between the gyro & the receiver, INSTEAD of between the main esc and the receiver. When is it advisable to use adapter between the gyro and the RX? Can I do this with my setup?
e) I.E. Is MIXING used when you do NOT have a HH gyro and ADVANCED GYRO CONTROLS used when you do have a HH gyro?


f) I am also confused about the meaning of the “Main Throttle” in the “Controlling TREC from the computer”. I understand that the Mix Input is used to simulate the signal coming FROM the main motor, but I do not understand what is meant by: “The Main Throttle slider is the just like the prominent input to the ESC.“ Please can you clarify?

g) On the GUI, what is the "Gain", what is it controlling?


Many thanks

Campbell Grant

thiswillfly

eheheh

agree totally that our views are right and well founded.

have given up a bit since I lashed out $80 for a HH gyro to still have problems.

would appreciate any feedback when you get your TREC - sure it will fix all the problems.

cheers

marked23

thiswillfly and eheheh,

[link=http://www.dionysusdesign.com/FAQ.shtml]http://www.dionysusdesign.com/FAQ.shtml[/link]
Check out questions 5, 6 and 10.

thiswillfly,
Did you try putting the Pixie7p on the tail instead of the main? Try it with, and without, throttle self-calibration. I'm guessing the GWS 100E doesn't have enough throttle steps for your situation. I use a GWS ICS-50, a less powerful esc; it works great.

-Mark

quaker1

I used a pixie7p on the tail and ended up selling it, the GWS ICS-50 worked much better in this case I could get the gyro gain much higher.