Twister CP & Sanwa TX

[wessex boy]

Help! This is my First Post, so please be Gentle!
I have bought a Twister 3d Expert (CP) that had been traded in at my Local Model Shop. I have had a Hirobo XRB for a while and was looking for the next step, I also have a number of fixed wing Models.

I brought it home and set about setting it up with my Sanwa RD6000. The previous owner had fitted an RCMart Micro Receiver. I have Elevator in 1, Aileron in 2 and Pitch in 6 and it is running in CP3F CCPM Mode

This is where the problems start....
At first I thought that the Cyclic was running in the reverse sense (pitch forward, pitched back, cyclic left moved the disk right, etc) so I spent a good 2-3 hours over the next few evenings reversing servos and moving servo arms to try and sort it out, getting totally dismayed at the complete lack of logic that CCPM seems to run....then last night it dawned on me, the reason the cyclic works in reverse is because the collective is working backwards!

As I add collective the blades start at a slight negative pitch and get worse! Hence Cyclic working opposite, it is pushing itself into the floor!
I have tried doing servo reverse on pitch, but the CCPM mixing monster then switches all the channels around at random so the swash plate is at a strange angle...

I have spent some time on full sized Helis (see Avatar) so understand the Principles of Rotary flight, but this has me foxed...

Any Help gratefully received!

[jimbob]

At this I'd start again with a new model memory and your swash plate type selected but leave everything as standard.
Disconnect the motor and check the following.
1. pitch up, the swash rises and vica-versa.
2. elevator forward, swash tilts forward and vica-versa.
3. aileron left, swash tilts left and vica-versa.

Good luck

[wessex boy]

Cyclic works OK, the Swash rises, but the blades increase their Negative pitch!
This is why I didn't notice the collective, I always assumed that the swash goes up to increase Pitch, but mine has to go down which doesn't seem right

[jimbob]

I'm not familiar with the twister CP I have to say, but it doesnt sound right to me - all other helis I;ve had have the swash rising for +ve pitch.
Check the linkages between the swash sides to the arms to the blades.
Its not that you have the blades on backwards is it? It looks like -ve pitch cos theyre reversed?

[wessex boy]

I did think that last night, they looked the same as the photos on the box/book, I will re-check them, although there is no good photos of how the linkages should look.
I will take some photos and post them if I get the chance at lunchtime

[jimbob]

From the top, the blades should rotate clockwise.
The control balls on the bade grips should be to the trailing edge side of the blades.
theres a link staight up from the blade grip to the arm, and a link from the other side of the arm down to the swash.
That should be enough to confirm everything.

[wessex boy]

Sorry I may have just confused you this is the CP version of the Twister 3D, I have just done a search ion the interweb for pictures, and the Twister CP that appears is not the same as mine!

I must remind myself not to buy second hand again, It is much easier to sort it out from scratch....

[jimbob]

oh- well there are 2 versions I beleive....
Hope you get it sorted.

[wessex boy]

Twister 3D Collective Reversed

I have done some more research and some testing/playing and this is what I have discovered:

• The collective does indeed work in the 'wrong' sense on these apparently
• Even though they have been 'test flown' most won't fly straight from the box
• I had to adjust my pushrods down by 14 turns to get a neutral pitch setting (the previous owner can't have flown it!)
• I can get the cyclic working in the correct sense with the collective opposite
• I can get the collective working in the correct sense but the Cyclic opposite (using servo reverse)
• If I do servo reverse on 1 or 2 of the servos only, the CCPM acts in a very strange way
• If I swap Channels 2 & 6 then collective and pitch work correctly, roll is in reverse...
• If this was a 'normal' heli I would have been flying last Sunday!!!

What am I doing wrong? why does the servo reverse behave so oddly in CCPM? Is my Sanwa RD6000 just not compatible with this?

answers on a postcard please.....

[Bikeracer]

I'm pretty new at this,but I seem to remember in one of the Finless videos on Helifreak talking about getting the CCPM set up wrong and which servos to adjust.

They're good informative videos anyway,I downloaded them and it makes it easy to play and pause while you're actually trying to make adjustments.

I wish I could offer you a better answer,but that's the limit of my experience.

The only other thing I can think of is if you've had the links off at all you might have them transposed on one of the mixer arms.IIRC from the TwisterCP I borrowed,the long link from the swash plate goes to the right hand side of the mixer arm.

Allan

[wessex boy]

BikeRacer, thanks I will have a look at the vids, I have registered and posted the question on Helifreaks.
I have methodically gone through every Servo/Channel combination (6) and every reverse/normal combination (8) and logged the results
I can only either get the Cyclic correct and the Collective reversed, or the Collective correct and the Cyclic 180 deg out...I am wondering if it is my tranny, I just wish that the servo reversing had some more intelligence and reversed the function directly

[wessex boy]

Sussed it!
Through my trial of all 48 combinations of Servo/Channel/Reversing I could get 2 out of 3 channels working in the correct sense the 3rd opposite.
I wondered if my telling it my CCPM mode was Elevator rear instead of forward as it should be and looking on my spreadsheet for the Collective/Roll correct, Pitch opposite plugs/setting, with a bit of twiddling, it seems to be correct!
Just need it to stop raining so that I can get outside & try it.
Just have to practice on my XRB indoors in the meantime...
Thanks for the suggestions everybody, I knew it must work somehow...