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Old Dec 04, 2008, 05:23 AM
Let slip the dogs of war!
Park_Flyer's Avatar
United States, VA, Virginia Beach
Joined Jun 2005
1,708 Posts
Quote:
Originally Posted by unloco2
Got a question, when we talk about down thrust on a midwing pusher, what do we mean? Is it the same as on a standard motor and prop on the nose, or does pointing the motor thrust line down force the plane nose to go up? Totally confused.
I would have to say that down thrust means the same regardless of the motor orientation you're mounting the motor, so that the thrust line points downward. This would be true for an aft-mounted pusher as well.

That said, adding down thrust to a mid-mounted pusher like this one seems kind of pointless. If you think about it, when the thrust hits the flat plate behind the motor, it will be diverted back to essentially a straight line following the top of the flat plate. For this aircraft, you should mount the motor with straight thrust lines.

Ben
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Old Dec 04, 2008, 09:46 AM
I believe in Kool Aid
Guppy Driver's Avatar
Glendale, AZ
Joined Jan 2008
425 Posts
Quote:
Originally Posted by benhobe
That said, adding down thrust to a mid-mounted pusher like this one seems kind of pointless. If you think about it, when the thrust hits the flat plate behind the motor, it will be diverted back to essentially a straight line following the top of the flat plate. For this aircraft, you should mount the motor with straight thrust lines.

Ben
Well...kind of. I inadvertently added some up thrust to my SU-27XXL when I replaced the original motor with a brushless. (Pointing the prop end of a pusher configuration up pitches the nose of the airplane up in flight as more power is applied) It flies fine and it's better than causing the nose to pitch down as the ground is ALWAYS down there somehwere.

You are absolutely right that mid-mounted pusher prop jets should have straight thrust lines.
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Old Dec 10, 2008, 11:39 PM
Registered User
Joined Dec 2008
3 Posts
Quote:
Originally Posted by jdsu
hello guys,


I maidened my f-22 yesterday in little wind (5-7mph). it flew beautifully.

this is my first scratch build foamie and first with elevon setup.

cg was right on spot as mehtioned in this thread before.

radio was little glitchy.

I had setup for very low rates so roll was slow.

will increate aileron little more and it will be lots of fun.

spec: triple stator park jet motor. APC 7x5ep , 35amp esc. 2 HS55 servo.

3s A123 cells from VXP battery (b&d) 1100mAh. it lasts about 8-9 mins and charges fast under 15mins at 4C.

overall weight about 16oz.. (battery alone is 5 oz.)

Hi there,

I have the same thing as your but have problem with the propeller. I also have the APC 7x5ep but the air flow was in different direct. How do you solve this?

I need the airflow in red arrow?

please help thank you
Regards
dvdykc
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Old Dec 11, 2008, 12:09 AM
Registered User
Ipoh, Perak Malaysia
Joined Jul 2006
4,005 Posts
Quote:
Originally Posted by dvdykc
Hi there,

I have the same thing as your but have problem with the propeller. I also have the APC 7x5ep but the air flow was in different direct. How do you solve this?

I need the airflow in red arrow?

please help thank you
Regards
dvdykc

Just switch any 2 of the three wires between the ESC and the motor and the motor will spin the other way. Make sure the prop is installed in the right direction, i.e. with the small numbers denoting the prop size facing the front of the plane.

chewy
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Old Dec 18, 2008, 07:19 AM
new pic, same plane....
sketchanderase's Avatar
Dayton MN
Joined Jan 2008
1,055 Posts
you dont really need ailerons or rudder for this plane, i built one from these plans with a 20 inch ws 28 inch length and it flies really great with just the elevons.......
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Old Dec 18, 2008, 07:20 AM
new pic, same plane....
sketchanderase's Avatar
Dayton MN
Joined Jan 2008
1,055 Posts
what paint is it on the one posted a few pages back?
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Old Dec 18, 2008, 04:53 PM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,187 Posts
You're right, ailerons and rudder are not required. But I do recommend adding ailerons for the "fun" factor. And avoid rudder at all. Not needed and just adds weight and expense.

Which plane are you asking about on the paint? Which post #? If you mean post 743, it was done with Testors spray paint. Color 1930 for the light grey, 1992 for the dark grey.

Pat
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Old Dec 18, 2008, 05:15 PM
new pic, same plane....
sketchanderase's Avatar
Dayton MN
Joined Jan 2008
1,055 Posts
probably that post. I have a testors all purpose enamel spray paint in "dark aircraft Grey" would that be pretty much the right look?
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Old Dec 18, 2008, 05:58 PM
Pusher jets rule!
crxmanpat's Avatar
Mesa, AZ
Joined Jan 2006
17,187 Posts
Should be good. I posted the numbers of my paints. I've found those two colors just about right for the two-tone grey paint jobs.

Pat
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Old Dec 18, 2008, 06:01 PM
new pic, same plane....
sketchanderase's Avatar
Dayton MN
Joined Jan 2008
1,055 Posts
they llook awesome on that plane! it might not look as good on mine because mine is out of blu cor not depron but...........should still look pretty good, i like the blue color with the painters tape cockpit that we added to balance it better and make it look better.....
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Old Dec 19, 2008, 06:23 AM
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superinstaller's Avatar
United States, SC, Greer
Joined May 2006
597 Posts
Ailerons are the way to go , especially if you like slow speed control as well as nice rolls. This bird just flies way better with them! Also increased wingspan 3in and .5 to the back or the tails makes for a stronger hinge
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Last edited by superinstaller; Dec 19, 2008 at 06:31 AM.
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Old Dec 19, 2008, 03:11 PM
Registered User
Switzerland
Joined Sep 2008
926 Posts
Hello,
I want to built this model. But I want to use the motors, the prop and the ESC that I have in stock:
I have those motors:
http://www.hobbycity.com/hobbycity/s...idProduct=5353
http://www.hobbycity.com/hobbycity/s...idProduct=5482
http://www.hobbycity.com/hobbycity/s...idProduct=2069
I have a 18A ESC
And prop 8x4, 6x4, 4.5x4, 7x35, 7x5, 7x6.
And lipo 3s1000mah 25C and 2s1000mah 25c
Do you think that it is possible to use one of them ?
REgards
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Old Dec 19, 2008, 05:58 PM
Registered User
superinstaller's Avatar
United States, SC, Greer
Joined May 2006
597 Posts
the top one would fly it. If you want cheap verticle climb power use this:

http://www.bphobbies.com/view.asp?id...7&pid=B2632603

Have two of these there awsome!
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Old Dec 19, 2008, 07:16 PM
Have Fun! Land, Sea or Air
jetcaptain's Avatar
United States, TX, Austin
Joined Jul 2006
1,354 Posts
I would say the top one with a 6x4 prop.

Quote:
Originally Posted by Cid156
Hello,
I want to built this model. But I want to use the motors, the prop and the ESC that I have in stock:
I have those motors:
http://www.hobbycity.com/hobbycity/s...idProduct=5353
http://www.hobbycity.com/hobbycity/s...idProduct=5482
http://www.hobbycity.com/hobbycity/s...idProduct=2069
I have a 18A ESC
And prop 8x4, 6x4, 4.5x4, 7x35, 7x5, 7x6.
And lipo 3s1000mah 25C and 2s1000mah 25c
Do you think that it is possible to use one of them ?
REgards
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Old Dec 19, 2008, 08:31 PM
hobby-asia.com
uniquexme's Avatar
Malaysia
Joined Apr 2006
466 Posts
u mean that emax 2805 with 6x4? i assume that u use 2S rite? but i flew it on my zagi, i seems lack of power.
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