channel mixing for adjustable trim tabs on th fly.

[gsbuickman]

Hello everybody ,

I am shopping around for another radio. .Currently I have a Futaba 3pm & a tactic ttx-240. I had an fs-gt3c but the firmware on them is corrupt & the exp & end points won't work correctly.

I was looking at the gt3c and the turnigy gtx3 , but idk if they have the bugs in the firmware fixed. Losi kid is flashing the c model so something's going on with them.

Anyway, I've always wanted to build an fe with adjustable trim tabs on the third channel. That in itself is fairly easy, but I would like to have them proportional, so I can mix them on the fly depending on the water conditions....

Therefore I think I might scoop up the Turnigy 3XS. http://www.ebay.com/itm/261293842655...84.m1423.l2649

I am looking for advice on how to setup proportional trim tabs, since i' haven't played with them yet. Idk if there are exp & trims on channel 3, or its possible to set them up on a mixer ?.

Any thoughts ?, Thanks guys

[tlandauer]

A third channel still can only control the two trim tabs together---two servos with a y-harness connected to the receiver, if you want individual adjustment on each trim tab, don't you need four channels?
I have a Spektrum DX3E---a fairly basic but useful 3 channel unit. You can have End Point Ajustment on the 3rd ch. That ch. also has a switch that is labeled "2 position" which is just what it means, one end to the other end, you can dial in the amount of travel---good for 2 speed transmission, like low and high gear.
Then it has "3 position", in addition to the two ends, it has a middle point.
last setting is "leanear"---good for fuel mixing.
I am sure there are fancier units , but this is what I have and it came with the Twin Hammer Truck which has a 2-speed tranny. Truck is sold by Horizon Hobby. This radio was sold as part of RTR boat radio by ProBoat sometime ago, I have several and I am extremely pleased with them, but current ProBoat RTR radio is a more economical version and has only 2 channels. I find the feel is MUCH cheaper.

[T.S.Davis]

I always wanted to try this with an offshore boat and mix it with the steering so that when you're going straight and wide open the tabs are level and then when you lay into a turn the would kick down a tick. Not sure if it would be worth all the tweaking it would take to get it perfect.

[HTVboats]

I have used 3rd channel tabs on mono's and power trim units on outboards. In heat racing it if just not practical to hunt for a sweet spot 12 times in a 6 lap heat. What does work is an up or down preset for a up/down, mild or wild setting. Down wind we trim up and opposite into the wind. If you use it to enhance cornering you need to set the boat before you turn or you can trip yourself in the middle of a turn. The 3rd channel on the handle button on Flysky's toggles up to down and you can preset your limits mechanically or with end point adjustments on the radio. At the end day we lost more heats trying to be too cute.
Mic

[srislash]

Dang you ,quit giving me ideas to do to a new boat. Haha

You want a Spektrum 4s,I just got one and I am sure you can do just what you are looking for. You can link in twin Esc's to slow one a tad based on steering input so you can do some tabs as well. I would run a pair of Spektrum A7000 retract servos for something strong. They are slow but shouldn't matter and they are cheap. Just got one for $25 on eBay

[T.S.Davis]

I tried it on a canard wing and my brain wasn't fast enough to remember where it was set last. That's why I was thinking a mix where the tab adjusts as you use rudder input. I could see that getting twitchy though. You try to compensate for a dead boat and end up hooking like crazy.

[gsbuickman]

Dang you ,quit giving me ideas to do to a new boat. Haha

You want a Spektrum 4s,I just got one and I am sure you can do just what you are looking for. You can link in twin Esc's to slow one a tad based on steering input so you can do some tabs as well. I would run a pair of Spektrum A7000 retract servos for something strong. They are slow but shouldn't matter and they are cheap. Just got one for $25 on eBay

Ha ha ha ha, what Slash ?. Like a servo mounted turrent water cannon, windshield washer pump fed from a transom pick up ......

[Fluid]

There is a reason that offshore boats have two people in the cockpit - there's too much for the driver to manage by himself between throttles, outdrive adjustments and trim tabs.

IMO for FE racing - KISS.



.

[gsbuickman]

I tried it on a canard wing and my brain wasn't fast enough to remember where it was set last. That's why I was thinking a mix where the tab adjusts as you use rudder input. I could see that getting twitchy though. You try to compensate for a dead boat and end up hooking like crazy.

That's exactly what I was thinking TS . I thought it would be cool if the tabs were mixed with rudder. Right turn the right tab drops down & the left tab comes up. Reverse that for a left turn. The kicker would be to have the tabs go up off the throttle, but yet as you get on the throttle they go down to neutral (straight out) with a Lil' trim adjustment for conditions. That would be the cat's meow........

[gsbuickman]

There is a reason that offshore boats have two people in the cockpit - there's too much for the driver to manage by himself between throttles, outdrive adjustments and trim tabs.

IMO for FE racing - KISS.



.

I agree Fluid, but I know it can be done. Our resident rc guru @ hobbytown did it. Look at all the bling junk the scaler crawlers are doing now. Rotating drivers heads with steering input, winches, hydraulic lift kits etc....

[srislash]

Ha ha ha ha, what Slash ?. Like a servo mounted turrent water cannon, windshield washer pump fed from a transom pick up ......

Did that years back on a PT boat.

Hehe, and heads that went left and right on my Graupner Systems7 cat with the rudder. And the capsules raised and lowered on that one too. Anything can be done, it just takes time and ingenuity.

[gsbuickman]

QUOTE=srislash;536126]Did that years back on a PT boat.

Hehe, and heads that went left and right on my Graupner Systems7 cat with the rudder. And the capsules raised and lowered on that one too. Anything can be done, it just takes time and ingenuity.[/QUOTE]

That's look Slash, I think we all have at one time. l8r g8r just pick up an original, still in the box, wood pt-109 kit. He's about got it to the point where he can lay glass over the hull. It'll be a bit heavy when he's done with it, but it'll be nice.

I was planning on buying a turnigy 3xs, but I looked into it a bit more. I think a 4 channel with channel mixing will get it done. Well, I just made a deal on an airtronics m11 to play with. I should have it in the morning' .

[srislash]

A bit of weight in a PT won't be bad.

[gsbuickman]

That's cool, I'll tell him you agree when he brings the m11 over in the morning. I suggested he spray it with a couple coats of epoxy to save weight & still seal the hull.

[srislash]

The weight will help it throw that bow roll of water that is just sooo PT.:-)
Those M11's look like a nice radio. Much like a Speky.