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Endgame IV Build

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Ken Culbertson:
Construction underway.  First order of business is always the stab with me.  Then I make the fuselage.  Last, the wing.  Just me.  I like cockpit detail so I make the fuselage with a removable cockpit module so that I can work on it whenever I get the urge then glue it in at the last minute, of make it a hatch.

Some pictures. Stab is using pocket hinges from Mark Wood's skunkworks.  They are recessed 1/8" into the TE.  The TE is 1/2" thick and airfoiled from a .025 radius LE to a 5/16" TE.  1/32" thicker than the elevator Top and Bottom.  Used wire to protect the LE.  The elevator is 1/4" tapered to 1/8" with full span 1/4" fences on the TE.

Fuselage will have "X" bracing in place of formers.  Sides, top, bottom and center.  Remember how solid those old Comet  kits were.  Without all that pounding from an IC I think this construction shows promise. 

More to come.

Ken Culbertson:
Got the aft fuselage framed.  The 1 1/6 sides are fine.  The twist capability is next to nil and I don't even have the bottom framing.  That goes on after the pushrod is in.  53 grams including the CF doublers in the unframed nose.  It is going to be a twin so all that will go in the nose is the battery and timer and perhaps the ESC's.  I haven't decided if I am putting them in nose or the wing.

Ken

For what it is worth.  That .3mm CF Sheet is fantastic.  It cuts with scissors and is stronger and lighter than plywoood.  The wing LE is reinforced for the pull test.  I am going to use .5mm for doublers in the motor nacelles.

Ken Culbertson:
One step closer.  I have molded the top aft fuselage. 59 grams as it sits.  Seems a bit light since it only weight 53 grams before the top shell.  I will never use blocks again, that is for sure!  Still trying to figure out where to put the ESC's.  In the center with three long motor wires and short battery wires or in the nacelles with short motor wires and long battery leads.
I am using BadAss 2320-850 motors on a 2800mah 6s battery,  If I cheat and use 13gauge wire I should be OK either way.  I have a question on the long motor wires if anybody knows.  Should I twist them so that there is not a long stretch with them straight?  I suspect it doesn't matter.

Ken

Wolfgang Nieuwkamp:
Nice project!! An ESC does not like twisted motor wires. I would use the motor wires as supplied.

Regards,

Wolfgang

Ken Culbertson:

--- Quote from: Wolfgang Nieuwkamp on January 20, 2024, 03:03:14 PM ---Nice project!! An ESC does not like twisted motor wires. I would use the motor wires as supplied.

Regards,

Wolfgang

--- End quote ---
Thanks for following the thread.  You were the inspiration for my Canard.  IMHO it has been a huge success.   I hope you have had a chance to see it in action.  If not here is a link.



This was only the 4th or 5th flight on the plane so it is still *way* out of trim.  The overall pattern is still a bit rough but watch the corners!  These are about 1/2 the tightest it will turn.  It will do a 90 degree turn in about 2 plane lengths - scarry.  Unfortunately, it has a stock Geo-Bolt wing and I don't think at 68oz, the center section is strong enough to take that kind of corner over time. The only design issue that I encountered was a tendency to self-tighten in the rounds.  I got that trimmed out later by adjusting the flap elevator ratios.  The III has a logarithmic flap horn and it was allowing too much elevator in the rounds.  I am not going to use one in IV.  Don't need it with the canard.

I am going to stiffen the center section on the new one.  Partly because it is weak on the Geo-XL I am using in this build but also because it will be a twin and will need the extra support.

Ken

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