Mud Duck Aviation Forums

FUDDLOW TAKES HIS LAST 400 FT DEATH DIVE AND STRIPS AN ELEVATOR SERVO TRING TO BREAK OUT OF THE DIVE.I GOT IT TO COME UP A LITTLE BUT ONCE THE SERVO GAVE OUT IT WAS ALL BUT OVER AND ALMOST STRAIGHT IN IT WENT..POSTER BOARD PLANES ACTUALLY SURVIVE A LOT BETTER THAN BALSA WOOD.THE MAIN BOX SECTION CRUMPLED, THE FRONT ENGINE SECTION REMAINED ALMOST ENTACT. THE LAST SECTION WAS ALMOST UNDAMAGED WITH ONLY VERY MINOR SEPERATION OF THE BOTTOM SEAM  ON ONE SIDE.. THE WING STRUTS WERE UNDAMAGED, THE FRONT WING MOUNTS WERE STILL ATTACHED, THE REAR WING MOUNTS BROKE OFF AT THE REAR WING ATACHMENT POINT ONLY. AT IT CRASHED STRAIGHT IN THE ENDS OF THE WINGS HIT THE GROUND FIRST ON THE TIPS..SOME OF THE BOX FORMERS BROKE LOOSE AND A COUPLE OF THE WING RIBS CRACKED. BOTH 2/3 RD'S  OF THE WINGS ARE STILL STRUCTUALY SOUND THE OUTER 1/3 ARE LOOSE... THE CARBON FIBER LEADING EDGE IS NOT BROKEN THE REAR TRAILING EDGE IS ALSO NOT BROKEN OR LOOSE.THE ENGINE IS FULL OF DIRT SO IT GETS A TEAR DOWN FOR INSPECTION FROM THE BACK SIDE INSPECTION COVER.THE SPINNER AND PROP ARE TOAST. THE LANDING GEAR IS TOTALLY ENTACT.EACH LEG WAS BENT BACKWARDS ABOUT 20 DEGREES.SINCE THERE IS LITTLE DAMAGE TO REAR SECTION I WILL MAKE A NEW MIDDLE BOX SECTION IN ITS ENTIRITY AND GRAFT THE REAR AND FRONT SECTIONS BACK ON.THE BOX SECTION WILL BE SMALLER THAN THE ORIGINAL BY ONLY THE THICKNESS OF THE FOAM BOARD SO I HAVE LOTS OF PLAY FOR ALIGNMENT OF THE FRONT AND REAR. THE NEW MIDDLE SECTION WILL BE A LITTLE HEAVYER BUT IT WILL ALSO INCORPORATE A NEW DESIGNED BOTTOM FLOOR WITH LIGHT PLY SO WHEN I BOLT THE LANDING GEAR ASSEMBLY ON I WILL HAVE BLIND NUTS TO SECURE TO ALSO LIGHT PLY WILL BE IN AREAS WERE I NEED TO SECURE THE FRONT AND REAR SECTIONS.ON A BIG PLANE OF POSTER BOARD THE MIDDLE SECTION WEAK POINTS ARE ONLY THE SHEER STRENGTH OF THE PAPER ON THE POSTER BOARD.BECAUSE OF ITS SIZE I FEEL SOME INSIDE  LIGHT PLY WILL REALLY MAKE THE DIFFERANCE.I WILL BE SURE TO TAKE LOTS OF LITTLE VIDEO CLIPS FOR ALL TO SEE.FUDDLOW WENT IN AT 19 POUNDS SO WHEN IM DONE I WILL PUT HIM BACK ON THE SCALES AFTER FUDDLOW COMES OUT OF INTENSIVE CARE. ITS THE JOURNEY THATS MOST INTREEGING TO ME.IF ANYONE HAS ANY IDEAS ON HOW TO MAKE IT A LITTLE BETTER LET ME KNOW I COULD ALWAYS USE THE HELP.ONE THING FOR SURE BIG DUCKS SHOULD HAVE BIG METAL GEAR SERVOS ON THE RUDDER AND ESPECIALLY THE ELEVATOR... THEY MUST TAKE A LOT OF STRESS PUSHING AND PULLING.THE MAIN BOX NOW WILL BE ULTRA STRONG AT THE BOTTOM OF THE BOX.AS ANDREW DICE CLAY WOULD SAY OHHHHHHHHHHHHHH DUCK.................I HAVE IT ON YOUTUBE UNDER "FUDDLOW TAKES A 400 FT DEATH DIVE" LEO

Hey Leo,

 Sorry to hear (and see the results of) your crash.  I don't specify the need for heavy duty servos on the Duck sedigns because almost everyone I speak to fly thier Ducks like ballons.  I rarely expect somone to come along and push the envelope like you did.  I should have anticipated it I guess, but you had said (and shown) you were doing those 400' dives and kept suceeding, I guess I figured you were using something stonger since they were working.

  So yes, anyone looking to fly the Agri-Duck (or Mud Duck) in a manner that is more than "lazy", a good practice would be to use something with higher torque (better than standard) and ball bearings (BB) are a must on the tail.  The rudder could probably fair well with a good BB sport servo unless you are really pushing the laws of physics.  The Elevator servo is your lifeline with these planes, a good Sport servo should be used even for regular flying (although many, including I have tempted fate with a cheap 'ole used S148)  If you want to try to "wring" out your Duck any, opt of a STRONG servo, a metal gear is safest and a coreless, high torque servo is recommended.

  Leo added more area to the elevator surface which wasn't originally designed into it. I would recommend to anyone adding area to a control surface (on any plane) to not forget about the additional load transmitted to the servo and the control rods and horns, they all become more stressed.  It is very easy to forget about that, especially when the modification takes place after the initial building.

  Here is a link to Leo's NTSB investigation video:

http://www.youtube.com/watch?v=DdANRM1H1_I

 
(NEW VIEWERS: keep in mind Leo has modified his Agri-Duck, incl. landing gear, extra bracing, extra control surface area, etc.,  this is not a stock Duck. See his other posts and videos on these forums to see what he's done )