Reversing one servo on a Y lead for flaps

[thevon]

In another thread I asked a question:

Mikey100 was just over here looking at a plane and he only has a DX6i. As far as we can tell, it doesn't have 4 servo wing mixing ... it only has ability for one flap channel. Is there any way of rigging up a 2-servo flap setup to one channel? Problem is the servos are naturally facing opposite ways, so they rotate in opposite directions, so a Y lead wouldn't work. Does anyone have any ideas?


I got a reply on RCG regarding one channel - 2 servo flaps, and there's a doohicky you can get that will do it!This shows a description, but is in the UK:
www.servoshop.co.uk/index.php?pid=JP7721044&area=ACCS

And here it is available in Australia
www.rojshobbies.com/radio%20stuff.html

But ... there is some comment that they can be problematic.
www.rcuniverse.com/forum/m_4776953/printable.htm

So apparently you can reverse 2 pairs of connections inside the servo. Here's the RCG reply
www.rcgroups.com/forums/showthread.php?t=995652

[jirvin4505]

You could also use programmable digital servos and program the servo to work in reverse. This solution may offer more choices with centering and travel adjustments.

cheers jeff
Skyboyken has experience with Hyperion digitals

[thevon]

Thanks Jeff. The Albatross which Mikey100 has now bought has servos fitted, so he's looking for something using existing setup rather than changing servos. He seems to have worked out a way using the radio with flaps on throttle for one servo and the other one mixed on the gear channel at 100% reverse (I think).

[mikey100]

Thanks guys. I will try...
1. putting flaps on throttle lever and other on gear channel and mixing them. or if no success...
2. purchasing a reversing y-lead with centering pot. Total=$36 posted.
thanks.

[mikey100]

Ok. I have purchased a reversing y-lead which has a centering pot. Have set it up and all works well....except- every now and again when I turn on, the flap servo on the 'centering pot' side looses its centre and has to be centered again. A simple job, but one that does not instill trust in me that it wont happen in the air...and it is a bit of a 'pain in the a**.'
Any ideas? (I dont want to rip servoes out and resolder wires etc. to change their direction, etc...just want a simple solution.)

[sean]

Hey Mikey, how did you go with the throttle to gear mix? I've never looked at a DX6i but I know that mix works on the JR Max 66 and 2610.

One idea to fix it mechanically would be to remove one flap servo, flip it 180 degrees and reinstall it. A bit of stuffing around but once done you could be sure it'll work properly.

Sean.

[mikey100]

Thanks Sean. The throttle/gear mix was unsuccessful as these chanels deployed at a different rate, so only ok at full or nothing with places in between out of sinc. Using the reversing y-lead on throttle works beautifully....except for the above concern.
Dont want to be cutting out servoes ( Flipping a servo would not change the movement direction )or trying to install it turned 180 as the space is not conducive to it and I dont want to be opening and resoldering wires etc.
Reading on RC groups and others just re-center before each session......but am not 100% happy with this idea...
Could mix throttle+ extea channel, but ailerons on y-lead, so no differential or individual subtrim, and no flap option.

[thevon]

Mike ... buy a Multiplex C@ckpit SX radio and fit a 2.4g module to it!

[sean]

I know it doesn't look nice but if the flaps don't come down perfectly in sync it's actually barely noticable in the air. Before getting my current radio I flew my Carbon Bird mostly on a JR 2610 and briefly on a Max 66 and with a throttle>gear mix the flaps did exactly as you describe - near half stick one was a little lower than the other. I found this gave no noticable roll and was pretty much not noticable in flight. Ezza currently flies his Opus MC3 on a JR 2610 and the flaps do the same thing. If the flaps are waaay out of sync that might be different I guess. IMO it wouldn't hurt setting the radio up this way and test flying at a site with a nice big soft landing area to see what you think. If it's no good go back to the reversing y-lead.

Sean.

[mikey100]

Sean, are you sure. I was hoping to use a bit of down-flap as undercamber (with a little down-flap on the ailerons) in my current setup, having the down-elevator mix only come in during the later part of lowering the flaps. Also using your method I loose the ability to set differential on the ailerons. Is differential that important on my plane? I am VERY new at this game so ...what you think?

[mikey100]

Andrew...yes I know a bigger and better radio is the answer, but am very happy with the dx6i to this point. How much to buy a Multiplex C@ckpit SX radio and fit a 2.4g module to it? I have 5 Spectrum receivers in models now....are they still compatable with the Multiplex C@ckpit SX radio ?

[thevon]

Mike, for ages I tried the conservative approach of part flaps then progressing to full flaps later, but it was always a real handful. Too much ballooning or stalling or pitching. When I saw that Sean just pulls full flaps and lets the plane settle down, I tried it and it worked.

Part flaps doesn't give full elevator compensation, but it gives the wing maximum lift (it doesn't lift any harder beyond about 30 degrees flap - it just slows down as the flaps get steeper than that), so on half flap the plane just balloons up like crazy ... and if you set your comp elevator to fix that, it will pitch into a dive when you pull full flap. Similarly, if you have crow, then part flap won't lift the ailerons much ... again with the result that the wing has max lift on part flap. So just set up your elev comp to work for full flap ... get the plane cruising nice and steady and pull full flap.

[mikey100]

Cool Andrew. But wouldnt part flaps be good in marginal lift conditions by giving some undercamber when coupled with a little down-flap on the ailerons...for those sinking times. I agree, full-flap to down elevator for landings....just get it dialed to the right mix, then just wack en down!

[sean]

Hey Mike,

OK, to be on the safe side probably best to use the reversing mixer for now, it sounds much more complicated than I thought - are you saying that enabling the throttle>gear mix disables the ability to have differential? Next time you're up this way give us a yell and I can take a look.

I gotta say I don't like the idea of manually centring a flap every flight, it just sounds like trouble to me, which is why I reckon if you can do it via TX mixing that would be the best bet.

Regarding the out of sync flaps, to be a bit more specific if they start moving at the same time, stop moving at the same time, have the same start and end point and stay within say 5-10mm of each other throughout the entire movement then it should be OK. For camber changing you definitely do want each flap to have a similar throw but then you only need a few mm of camber and the flap throw should be very close in the first few mm of movement (I'm assuming
they are out of sync the most at 50% down?).

Hope there's a solution!

Sean.

[skyboyken]

Hi Mikey100,

as it happens I have just upgraded my transmitter, and so I happen to have a C@ckpit SX plus a conversion kit to adapt it to Spektrum 2.4GHz. I wasn't really thinking of selling it just yet but if it could solve a problem for you then PM me and I'll come up with a price for you.

As you probably know the SX will do all the good stuff with 4 servo wings - camber, reflex, crow - all with elevator compensation. It even does 3 flight modes which are useful and easy to set up and use, if not quite as powerful as on some other Tx'es.

The SX is a good and inexpensive glider radio for when you get sick of trying to get 2610's to do stuff they're not really made to do .

Ken.