Swanys website, [link]http://www.swanyshouse.com/mojo60/mojo60.aspx[/link], says 70 oz/in servos should work, but seems most people are installing 100+ oz servos. How much torque is really needed for a good 3D Mojo Moass?

More than you might think!

In flight, I've noticed a small amount of rudder blow-back when using Hitec HS5925 servos on the tail which are rated at 128oz/in on 6V.

It's not the linkages (metal arms, 4/40 clevises and carbon pushrods), it's the servo.

I've got Futaba 3010s on the ailerons and they're *awful*. There's now a good 3/8"-1/2" of slop (measured at the aileron trailing edge) due to slop in the output shaft on these servos. They are the *worst*.

I use Hitec 5625MG in mine. Many unknowing people think that using good digital servos in a profile is crazy but they are def. needed on this bird-the faster/stronger the better and having tight strong linkages make the difference in a good flying plane and an awesome flying plane. You **WILL** be able to tell the difference.

Thanks for the tips. Xjet, if your getting a "small amount" of blowback w/ a 128 oz-in servo, then I think I'll set my minimum torque requirement at ~130 oz-in, and then buy the fastest servo I can afford. I'm assuming you have the same 5925 (man thats a fast servo!!!) on elevator and are not experiencing blowback?

I'm not going to make excuses with this plane, I want it to be an all out monster. The only thing holding it back should be me.

Anyone have input on torque requirements for the ailerons????

Anything over 100 oz
Ailerons don't have to be MG, Rudder pretty much does.

I haven't noticed any blowback on elevator but it's not going to be as easy to spot their anyway (at least not visually).

I think the rudder requires more power because it's a long way from the rear point to the hinge-line which means the propwash has a lot of mechanical advantage. By comparison it's a shorter distance from the elevator hinge-line to the rear of that surface.

The Futaba 3010s I'm using have enough torque they're just silly-sloppy.

I am building a Moass 60 also. Futaba S3050 is what I plan to use all around (HS-85BB for throttle). Power for the servos will be a 3S lipo running through a Castle BEC http://www.castlecreations.com/products/cc_bec.html with the output voltage set at 6V. I choose these servos because of there weight, the higher output servos weight quite a bit more.

Keep in mind that even if you run 150oz servos but your battery voltage drops when the servos are under load you will have a huge drop in output power. It requires a substantial battery to power the HO servos.

My 40 sized Mojo was having blowback problems with my 6V nicd battery. Switching to the Lipo - BEC running at 6V cured the problem and also reduced weight.

Ryan

How hot does the Reg, get with the 3s lipo?

Try some Futaba 3305s and a 6V pack. These wont break the bank and are very stout. I would not use them in a pattern plane but they are perfect for a profile.

david

Sounds like a good idea, but I am resistant to move away from NiCad's because I would have to get a new charger. ughh... you do raise a good point though.

Get yourself a good 2/3A 1500mAH 5-cell NiMH pack and you'll never have any problems with voltage sag. Those packs will deliver 20A continuously without complaining!

But the battery of choice has to be A123. 6.2V with an incredible current capability and a 15-minute recharge (from flat) capability.

I've switched to A123/LiFePO4 in all my planes now (even my slabs) and would never go back to other chemistries. I can grab any plane in my hangar and go fly it without worrying if the battery has discharged over winter because A123/LiFePO4 packs also have a very, low rate of self-discharge.

The A123/LiFePO4s offer all the benefits of LiPo but with the following benefits:

1. they don't explode or catch on fire if you abuse them or something goes wrong
2. you can run them flat without damaging them
3. recharge times are around 15 minutes from flat
4. they have a low-enough voltage that you don't need a regulator for a 2-cell pack
5. they're cheaper than a LiPo/Regulator setup

What's not to like?

I went for hitec 5625s all round on 6v nimh and so far not had any problem. Im by no means a top end 3d pilot(yet) But sure ring it out and i have never notice any blow back. I am running some very tight linkages that are carbon fiber and 4/40 ball links that have no slop at all.

I have done some testing on the ground and the highest amp draw I could get was just under 2.5amps with (4) 9001's and (2) 9155's under full overload (on Ultra Stick Lite 1.20). Just warm was all I could get out of the Reg. Under what I think is normal loads I was showing around 1 amp.

When I mount the Reg in the plane I dont wrap in foam I just velcro it to a pc of foam. I have never had a problem.

Ryan