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Old Jan 28, 2013, 11:32 PM
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United States, AZ, Yuma
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on a twin, you generally want 0 down and 0 right thrust. location does not matter, tho keep in mind diff thrust will be more effecitive if the motors are far out wards...
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Old Jan 29, 2013, 09:15 PM
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Originally Posted by nemoskull View Post
on a twin, you generally want 0 down and 0 right thrust. location does not matter, tho keep in mind diff thrust will be more effecitive if the motors are far out wards...
thanks for input, yea I was concerned about being far enough out the wing for the diff thrust but not so far out to cause problems.Wasn't sure if there was some critical factor concerning placement, will probably place them about midway and see what happens.
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Old Jan 30, 2013, 08:33 PM
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mostly the problems occur for me with old brushed motors, one running better than the other. i would just say to get the same motors at the same time new. (same production run.)

maybe some one else can chine in on prop wash on the outer wings...

the tiwns work very well as a twin rudder, delete the center one. mostly cuz the prop wash.

must post pics!
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Old Jan 30, 2013, 08:53 PM
Row 0, Seat A
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Originally Posted by Meach_in_GA View Post
thanks for input, yea I was concerned about being far enough out the wing for the diff thrust but not so far out to cause problems.Wasn't sure if there was some critical factor concerning placement, will probably place them about midway and see what happens.
You really want to keep them as close to the fuselage as practical. This will decrease any adverse affects of thrust mismatch for normal flight, minimize reduced roll response due to the increased outboard mass, and you will have more than sufficient turning authority with differential thrust in flight and on the ground with the motors inboard.

Ted
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Old Jan 31, 2013, 02:38 PM
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yeah, forgot about mass. the father out the harder to roll. tho you might want that, it would help the plane resist rolling, like from the wind. but usualy thats not a very common thing to do.
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Old Jan 31, 2013, 08:49 PM
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Originally Posted by nemoskull View Post
mostly the problems occur for me with old brushed motors, one running better than the other. i would just say to get the same motors at the same time new. (same production run.)

maybe some one else can chine in on prop wash on the outer wings...

the tiwns work very well as a twin rudder, delete the center one. mostly cuz the prop wash.

must post pics!
Here is pic as it stands today.

Had heard that its best to place motor as close as allowable to fus., mine are about 35% out on the wing. Might make a new wing for other reasons after I give this one a go, and will prob put them in closer next time.

Using two new $6 motors from HK hoping they would match (have been using this motor on other projects and has taken a beating and has been great, currently on a Divinity 42" flying wing) if they do not match well hope to adjust using trim on diff. thrust.

Not using rudder, left the center vert stab. , might go back and add rudder later.

I've also added flaps, I wanted to try out using the 3 flap sw on my T. 9X

Still have landing gear to figure out, was waiting to see how my CG looked after intalling electronics.

Meach
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Old Feb 01, 2013, 02:26 AM
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9x upgraded firmware? open9x can adjust the points for the 3 pos switch. nice. i really miss mine. got to get a new one...
looks like a nice twins. you might need some rudder, tho.
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Old Feb 01, 2013, 08:52 AM
Row 0, Seat A
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Savannah, GA
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Here is pic as it stands today.

Had heard that its best to place motor as close as allowable to fus., mine are about 35% out on the wing. Might make a new wing for other reasons after I give this one a go, and will prob put them in closer next time.

Using two new $6 motors from HK hoping they would match (have been using this motor on other projects and has taken a beating and has been great, currently on a Divinity 42" flying wing) if they do not match well hope to adjust using trim on diff. thrust.

Not using rudder, left the center vert stab. , might go back and add rudder later.

I've also added flaps, I wanted to try out using the 3 flap sw on my T. 9X

Still have landing gear to figure out, was waiting to see how my CG looked after intalling electronics.

Meach
That looks good. It should do just fine with that motor placement and no rudder. I would expect it to be very responsive to differential thrust so you might anticipate the need for a lot of expo. You also don't need a high percentage of rudder to throttle mix. On my full size twin with "normal" motor placement 35% mix is plenty for any ground or flight maneuvering.

More pictures and a flight report when you can.

Ted
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Old Feb 03, 2013, 09:59 PM
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Well here she is ready for flight except for some minor adjustments. Will fly as soon as weather permits. According to my wattmeter the two motors together are putting out in excess of 250 watts, I didn't push it to 100% but close, I don't like pushing these cheap components to their limits. AUW of plane is about 37 0z or 2.3 pounds so should have more that 100 watts/lb. so I should be able to add some cargo with no problem later like bombs, etc.

I'm anxious to see how my home made landing gear works out.
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Old Feb 05, 2013, 10:21 PM
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Flight Update

Was able to get out and fly today, hope to get out again tomorrow. Didn't get any video as I was alone, perhaps someone else available tomorrow to film.

Plane flew great, plenty of power, most of the flight today was only 25% of throttle or so. Takes off great but wants to fly to the left during sustained flight, tried doing some trimming today but going to work on it again tomorrow. Had a problem with front landing gear where I was using some wire which didn't hold up, made the front like the rear which worked great (see new front in photos). Didn't help that during one landing I landed on the curb along the parking lot where we fly, I don't have a lot of experience landing (several of the planes I have built were without landing gear, gliders, wings, etc.)

Flaps also worked great using the 3 position flap switch on the 9X. The main wing has a 7" cord with an additional 2" for ailerons & flaps.

My horizontal stabilzer may need some bracing, it flexes as rudder moves.

Meach
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Old Feb 06, 2013, 09:12 AM
You're killin' me Smalls
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United States, NJ, Hillsborough Township
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Some day I will build an elevon twin pusher based on this general boxy design. I swear I will
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Old Feb 06, 2013, 06:42 PM
check for reversed controls
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United States, CA, Chino
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M ake it look like a Beechcraft Starship wida canard on the front.
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Old Feb 06, 2013, 08:18 PM
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Beech Starship

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M ake it look like a Beechcraft Starship wida canard on the front.
It would be a big stretch to transform the Cargo Twin into a Starship. I wished someone would come out with a reasonably priced model of the Beechcraft Starship. It is one my all time favorite designs.
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Last edited by Iflyrc_vic; Feb 06, 2013 at 08:19 PM. Reason: Typos
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Old Feb 06, 2013, 09:07 PM
check for reversed controls
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United States, CA, Chino
Joined Oct 2007
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There's only a few still flying . And if your not the guy I already told . I was lucky enough to see one of em climbing out from a departure outta John Wayne Air Port O C Ca. In Nov last year.
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Old Feb 07, 2013, 09:24 AM
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United States, NJ, Hillsborough Township
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Originally Posted by Iflyrc_vic View Post
It would be a big stretch to transform the Cargo Twin into a Starship. I wished someone would come out with a reasonably priced model of the Beechcraft Starship. It is one my all time favorite designs.
Kind of a starship but not that stretched beauty. Eagle 5 is what I've been quietly mulling in my head for months.
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