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Old May 05, 2006, 11:32 AM
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7 ft. span 757 - my first DF project


I'm designing this model based on the lessons learned from my MD-80 design.
Its a pusher prop design so you may not have seen it.
I've learned from an A-10 design years ago that a prop placed in front of a high bypass cowl looses a huge amount of efficiency.

I've seen a 757 kit here somewhere ( looks like a 737 to me) and the sound in the flight video was enough to sell me. So. . . . . . my 757 has to be ducted fan.

The idea is to use the tooling I have to make
the wings and fuselage,
stretch the gear and add trucks,
redesign the nose and tail
and mount the motors on the wings. Same plane, different configuration.
Last edited by sparks; Jul 07, 2006 at 09:26 AM. Reason: added current photo.
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Old May 05, 2006, 11:34 AM
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Pylon


The fan units are 90 mm. (close enough to scale for me)
Motor, Mega 22/30/3.
This should be enough since the projected weight of the model will be 6 to 7 pounds ready to fly.
I'm using light ply and balsa for the pylon construction.
Placement of the ESC is still in the air.
There is room in the pylon but behind the motor is an option too.
I'll start cutting the wing skins and ribs soon.
Old May 05, 2006, 02:07 PM
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Terrific looking MD80, even if it is propped.

Twin EDF's make beautiful music...

This will be a "must follow" thread...
Old May 05, 2006, 02:52 PM
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2 90mm fans should have more than enough thrust with the Megas to fly this jet.

Rob
Old May 05, 2006, 03:49 PM
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Or am I...
Cool. Lets see some progress!!
Old May 07, 2006, 02:34 PM
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Wings 1


This type of wing uses the Panel Type construction and is covered in the book Building with foam.
http://home.att.net/~parkflyerplastics

The wing skin and wing cores have been cut.
It took about 1/4 sheet of blue foam to get a good set of skins.
Cutting the dihedral angles with the skins and cores assembled is the most accurate way to get job done.
After the angle cuts have been made, the cores are held together with tape so the gaps for the spar and motor support can be cut.

The bottom wing skins are then bonded together , the wing core is placed on the skin so the ribs can be laid out.

More Tuesday.
Old May 09, 2006, 08:55 PM
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closeing


I've got the core all cut up and the ribs in place.
The controls cables have been ran so I'm ready to close it up.
The blue tube is going to be the conduit for the landing lights.
It shouldn't be long before I start the glass work.
Old May 09, 2006, 11:32 PM
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This is going to be sweet by the looks of it. What livery are you leaning towards on this?
Old May 10, 2006, 02:05 PM
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Im curious about your MD-80. Did you have a thread about this or anything I can see about it?

Im working up plans for an MD-80 myself, so you can imagine Im quite interested in yours.

Thanks!

Jason
Old May 10, 2006, 04:43 PM
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80 Plans


I'm afraid there's not much there but here it is.

https://www.rcgroups.com/forums/showthread.php?t=483632

I have to hold back on making posts because it will be a construction article soon.
Not knowing which images they will want to use keeps me from showing them.
However. . . . . . .I do have plans and plastic parts available.
Old May 10, 2006, 05:21 PM
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I'm in


Put me down for a set of plans and plastic parts.
Let me know when you are ready & how much
You do amazing work

Later
Wade
RCG Plus Member
Old May 11, 2006, 01:30 PM
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Quote:
Originally Posted by sparks
.........I do have plans and plastic parts available.
Yea? How can a guy get these plastic parts and plans?
Old May 11, 2006, 05:31 PM
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Give me a chance to figure the cost of the plastic and I'll make a post soon.
Old May 12, 2006, 09:58 AM
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You rock.
Old May 12, 2006, 05:18 PM
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To avoid confusion about the 757 I have posted plans and plastic information about the MD-80 in the thread located here. . . . .
https://www.rcgroups.com/forums/show...=2#post5466179

BTW
The wing has been glassed and I'll start on the fuselage soon.
I had to take a week off of the project to do some plastic tooling on a customers kits.
I should be able to fire up the bow next week.


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