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Old Nov 27, 2012, 06:58 AM
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Twin star 2. movie 12 (8 min 6 sec)
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Old Nov 28, 2012, 10:33 PM
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Really want to try differential thrust on my radio. Thinking about building up a Twinstar (or getting a Dynam Skybus). I'd much rather go with Multiplex.

Trying to shop for an easy drop-in motor. How many watts should I be looking at per motor to make the TwinStar II hum along?
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Old Nov 28, 2012, 11:19 PM
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Is there a particular reason why you want to mess with differential thrust? I played with it for about 10 minutes on my radio just for fun, but Y-ed the motors together for the final build. You almost certainly won't get the motors to run in sync if they're not Y-ed, which affects the cool factor. Further, it's another thing to go wrong. If your motors are on the same channel and there's a weird glitch, at least they behave together. If they're on separate ones, there's a chance they could act differently. Not trying to rain on your parade, but it's a chance I wouldn't take.

As a side note to everyone, don't believe you can fly this plane on one motor. I had mine set up with counter-rotating props to minimize p-factor. I lost one ESC (Thunderbird) at full throttle. The asymmetric thrust from the good motor threw me into a spin that ended in a parking lot. Perhaps it would have been possible to save if I had cut power, recovered, and gently applied the throttle. In the moment, though, the chance of everything happening just right to let you save it is pretty slim.
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Old Nov 29, 2012, 12:33 AM
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Originally Posted by TexasAggie View Post
Is there a particular reason why you want to mess with differential thrust? I played with it for about 10 minutes on my radio just for fun, but Y-ed the motors together for the final build.
It's the same reason why when you go bar-hopping in College Station, you try to hook up with ... say a very flexible yoga-practicing girl from New Delhi... because you've never tried before.

I may not keep differential thrust, but I want to try it. I think I got the radio part figured out attached to the rudder. Any tips on some good motors for the TwinStar?
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Old Nov 29, 2012, 01:08 AM
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Quote:
Originally Posted by Left Coast DJ View Post
Really want to try differential thrust on my radio. Thinking about building up a Twinstar (or getting a Dynam Skybus). I'd much rather go with Multiplex.

Trying to shop for an easy drop-in motor. How many watts should I be looking at per motor to make the TwinStar II hum along?
I use a 30% mix between the rudder and the two different brushless motors and their respective ESCs. I take the +ve lead out of one of the throttle leads to the RX. I mix throttle to Aux-2 at 100%

One tip on electric throttle/rudder mixing. Remember to add power on one side and reduce power on the other side. This is because unless you do this then at full throttle the rudder will have no effect on the motors.

I use the rudder to motor mix to execute much better stall turns and flat turns. It also makes knife-edge a lot more viable--twins tend to fight back to get straight line flight. The TS II has proverse roll and down coupling with rudder. Roughly 20% opposite aileron and 9-12% up elevator mix takes care of the worst of it. Not a bad idea to put the motor mixes on a switch.

2cents - Eric.
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Old Nov 29, 2012, 05:57 AM
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Good tips Eric.

And also, if you've got a floatplane, or one with wheels, or one without in snow, diff thrust is GREAT for turns when taxiing.
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Old Nov 29, 2012, 09:30 AM
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Originally Posted by Wind Junkie View Post
Good tips Eric.

And also, if you've got a floatplane, or one with wheels, or one without in snow, diff thrust is GREAT for turns when taxiing.
I have built 11 TS IIs in total. (2 for me). They were a particular favorite with the retired community due to easy launching and relatively tough constructon to deal with hanger-rash and various prangs! Plus they liked painting them :-)

All of them began with the brushed motors and used 2200 LIPO packs. Then along came the higher C ratings and 3000 mAh. It was not long before the brushed motors failed. Also the soldering on the MPX harness and aileron conector board was not good. If a motor was used with an out-of-balance prop the rear solder joint would break. You could not do differential thrust with the stock set-up and needed another brushed ESC--not really worth it.

And yes! they do not fly very well on one motor. Mainly because of the strong rolling effect of the rudder. This airplane will fly all day on rudder elevator. (They thermal quite well, especally with a lighter LIPO).

My latest (The FANSTAR II TWIN) has reduced dihedral which helps a little, butl high-wingers will usually roll with the rudder in the direction of the rudder. Once you mix in some rudder roll and dive correction you can fly with one motor! With one motor out there is just too much going on for the pilot unless you are gimbal-gifted or you have pre-programmed in some help.

Just for grins I put one motor on a switch and tested the above statement. With the rudder/aileron mix basically programmed to give you yaw instead of roll you can fly on one motor. It helps a lot if you drop the wing about 15 dgrees that has the power working. The best strategy is to cut the power and glide. The second you cut the power the TS II stops behaving like a bucking Bronco and is a Tamecat!.

I almost forgot, the go-to brushless power system that I and others used was the MPI upgrade combo specifically put together by MPI for the TS II. I must hasily add that it is expensive. More than a TS II costs, but it gives you great vertical and no issues like over heating etc. I put the ESCs in the wings between the nacelles and the fuselage. It came with APC props as well.

Since then HK has come to the fore with much cheaper products , but the MPI (Maxx Products International) Twinstar Brushless Comboupgrade has never let me down and is still kicking butt after 4 year-plus of regular flying from NJ to NEAT fair to Joe Nall eWeek, to good old Las Vegas.........

Sun's up! and did not win the $500M lotto -- I'll just have to go flying to make myself feel better...Eric.
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Old Nov 29, 2012, 09:53 AM
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Found some old pictures of MPI upgrade showing ESC positioning.

I should also mention that another cool option is to disable the rudder when you have the thrust differential engaged.

Don't plug the rudder into the rudder channel--leave it empty. Do the usual motor mixes on, say the mix switch.

Plug the rudder servo into, for example the gear or an auxilliary channel. Then mix the rudder channel to that channel with a switch.

Depending upon your radio, you can have all of these options while you fly:-

1. Rudder and diferentialf motor thrust control

2. No rudder and differential thrust

3. Rudder and no differential thrust

4. No rudder and no differential thrust--just aileorns and elevator, and power of course.

I use the mix s/w on my JR's and the gear channel lever as a switch.

Hard to get bored with all of that to play with.......right!

Regards,

Eric.
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Old Nov 29, 2012, 09:54 AM
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I would add that these motors drop in with four existing screws/holes to existing motor mounts,
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Old Nov 29, 2012, 01:15 PM
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Mpi data

I received an off-line question about the motors. It seems that I did not get a stock system from MPI. I usually talk to "Dean" and he must have substituted the combo that I was talking about to give me the perfprmance Iwas looking for. [has to go vertical :-) right? ]

I took a motor out to get some "data" pictures

Eric. - Hope this is clearer?
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Old Nov 30, 2012, 06:51 PM
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This Himax motors are fantastic! But a bit pricey. Anyone fly their TwinStar with a pair Exceed Rocket Motors from HobbyPartz.com?
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Old Dec 02, 2012, 08:03 AM
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Season's first snow

The season's first snow came tonight, and suddently the TS is my favourite plane again.

I have just replaced the 1600KV Turnigy Park300 motors (running 2S) with a set of Turnigy SK3 2822mm 1090KV (3S). Still APC 8x3.8SF counter rotating props. New motors seem less powerfull, but also less noisy, and hopefully more efficient. May switch to APC 8x6 thin electric props, but for now and the snow, I'll keep the 8x3.8s



TwinStar 2 snow touch'n'go onboard video (0 min 0 sec)
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Old Dec 02, 2012, 12:36 PM
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Quote:
Originally Posted by Left Coast DJ View Post
This Himax motors are fantastic! But a bit pricey. Anyone fly their TwinStar with a pair Exceed Rocket Motors from HobbyPartz.com?
Not pushing the Himax motors, but I would add that these brushless beasties, (and probably several other brushless motors), allow me to take off regular grass with ease. At least up to 3" long--dry or wet.

E.
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Old Dec 03, 2012, 11:30 PM
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Poor man's Himax 2815s:




Could they be too heavy at 92 grams each?
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Old Dec 04, 2012, 12:16 AM
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Originally Posted by Left Coast DJ View Post
Poor man's Himax 2815s:




Could they be too heavy at 92 grams each?
I would not begin to worry about the motor weight. The Fanstar (my EDF version) can carry a 2 x 3300 4S packs and still fly well. I fly my regular Twinstar II on a 4000 3S. Flys best on a 2700 3S - FYI.

E.
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