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(Another) P51-D swappable design/build log

#22
What are you powering this plane with, Jason?

I'd like to see what a CF 2812 would do. http://www.headsuphobby.com/Emax-CF2812-1600kv-Outrunner-Brushless-Motor-E-505.htm
I plan on testing it with my current FT Flyer power system but with a smaller prop than I usually fly.


At this point I'm calling it on this prototype. In the process of building it I've found all manner of points I need to redesign. One of the most glaring is the spar. I built the second wing and then realized I had no dihedral because of how I was following the flawed spar shape. I'm going to cut in the power pod notches and see if there are any glaring things I'll have to change for it but other than that I won't be taking this version of it any farther.

2013-11-30 14.40.51.jpg

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Screenshot_112913_121606_PM.jpg

I'll be going back to my plans and model and reworking them for a new version.

Design notes:
  1. Go back to model and use the 'virtual DTFB' technique of pulling the shapes into 3/16" thickness to plan for material thickness in folds
  2. Rework wing root slots in fuselage
  3. add tail assembly slots to fuselage
  4. Design notches into rear turtle deck for tail root
  5. Add labels to formers to note placement on fuselage
  6. add angle support for cockpit formers
  7. extend turtle deck covering 1/2" on both edges
  8. leave cockpit turtle deck paper solid to allow it to be trimmed when placed as cockpit formers may be off a bit per build
  9. Try to design a more solid folding of the wing parts
  10. extend wing bottom in mid wing back to trailing edge
  11. Add in servo lead holes to wing mid section
  12. redesign wing spar
  13. design hinge area under nose for pod insertion
  14. design cockpit formers for material thickness
  15. add in pads for gap on side of powerpod in the nose area
 
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#24
While I go back and make my revisions I thought I'd share some of the history and research that I've pulled together for this build.

Quick history:
The Mustang was designed and built by North American Aviation under the direction of lead engineer Edgar Schmued. It was in response to a request by the British Purchasing Commission and was first flown operationally by the Royal Air Force (RAF). In just 102 days after the contract for the aircraft was signed it had it's first flight on October 26th.

One of the Mustang's cutting edge features was a wing designed using laminar flow airfoils

Pn37533.png
Source

Technical Details:
General overview

p51b_1_3v_c_cutaway.jpg
Source


Drawings:
3-View-AD.jpg
Source

Markings:
RCGroups Thread

Invasion stripes: The black and white stripes seen on many mustangs were used to help visually identify friendly aircraft of the allied air corps during and after the Normandy landings of WWII. In many cases these stripes were added to the aircraft mere hours before an operation and were done quickly and free handed by ground crews.
Invasionstripes-1.jpg
Source

The colorful nose and tail markings denoted what fighter group a mustang belonged to.
 
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#25
I've worked out a new arrangement for the wing folding. In the mean time here's a time-lapse of setting up an improved design. It will have a better and stronger wing geometry and will encompass all of the design notes from the first version.
 
#32
Now I'm wondering if I would be able to actually get some 'simple' retracts working with a 9g servo. Has anyone done this?

I came across a gearing design that includes a bit of locking over on RCGroups
a319212-67-bealeg.gif
I'm thinking that this could be carefully cut and built from the type of ply we use for our firewalls, not something that would last forever but would be easy enough to rebuild/repair for a Swappapble warbird.
 
#33

Now I'm ready to size up the plans, print and cut foam.... again. ;)

This version should be a little bit smaller than the last overall and I've addressed all the design notes of the previous prototype.

 
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#34
Plans version 2.0 all printed and taped up.
Photo Dec 09, 7 56 43 PM.jpg

I got to thinking I hadn't done a gut check to see how my mustang looks compared to another mustang. I found a model of a P51D on the Google SketchUp warehouse and loaded it in next to mine. Gave them a sketch style for visual comparison:

P51D-v2-003.png
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P51D-v2-001.png
P51D-v2-002.png

I'm happy with the proportions. Now with some luck I can get version 2.0 built and actually fly it.
 
#37
Jason, I'm so glad to see that you take the time to print your plans and assemble your plane the same way we would if we downloaded them. I'm with the rest of the group, can't wait for the plans! Great job
 
#38
Jason, your P51-D looks great!! How is it coming along? I can't wait for the plans.
Had to step away from my projects to deal with some rough holidays but I should be back in the groove here soon. I've got v2's wings cut and ready to glue but I need to make my servo extensions before I glue that up. The fuselage is dry fit and works well.
 

epicstrikard

Actual Pilot, RC Idiot
#39
I myself have an uncontrollable love for the P-51s. I would LOVE to be able to get the plans. Will you ever be making them available? Won't be able to take myself away from this thread for awhile :D