Mud Duck Aviation Forums

OK ITS TIME TO TALK WHAT NOT TO DO...TODAY MY THROTTLE SERVO FAILED AND WENT WILD..FULL THROTTLE THEN IDLE THEN 1/4 THROTTLE THEN IDLE...UNTIL IT WAS TIME TO THINK SAFTY FIRST... SO FORTUNATELY WE HAVE SOME 6 FT TALL MONSTER WEEDS AT THE END OF THE FIELD..SO I STUCK FUDDLOW IN FOR SOME WEED ABAITMENT..NO DAMAGE WHAT SO EVER . THE NIGHT BEFORE I ADDED SOME ALLOY EXTENDERS TO THE ELEVATOR..SO I COULD PUSH THE NOSE UP IF I HAD A DEAD STICK.THIS TIME IT WAS TAIL FIRST INTO THE BRAMBLE WEED.THE CAUSE WAS A EXPENSIVE MICRO SERVO GLUED TO THE FIRE WALL. AFTER SOME 15 FLIGHTS ITS SERVO FAILURE TIME..FROM VIBRATION.EVERYTHING IS OK TILL IT HAPPENS.SINCE THE AGRI DUCK IS NO SPEED RECORD HOLDER EVERYTHING HAPPENS RATHER SLOW..DO NOT MOUNT ANY SERVO DIRECTLY TO THE FIRE WALL BULK HEAD.IT WILL BITE SOONER OR LATER BUT IT WILL FAIL ,I LOOKED AT SOME BLOGS THAT WERE IN R/C UNIVERSE AND THEY ALL POINT TO THE SAME DIRECTION.ITS A NO NO.SO NOW I WILL MOUNT IT BACK AWAY FROM THE ENGINE AND USE A PLASTIC GOLDEN ROD  CABLE TO DO THE WORK FROM A DISTANCE AND THE SERVO MOUNTED ON STIFF FOAM WITH A SAFETY TY-RAP JUST IN CASE. ANOTHER POSSIBILITY IS A WAY TO KILL THE CD IGNITION ON DEMAND FOR TOTAL CONTROL MAYBE A SERVO FROM THE RECIEVER PACK THE CD IS DIFFERANT VOLTAGE THAN THE RECIEVER BATTERY.IT MUST BE STRICTLY CONTROLLED VOLTAGE LEVEL.ANY IDEAS OUT THERE LET ME KNOW..FUDDLOW IS A TOUGH BIRD INDEED ,LEO.

I always like to keep my servos away from the engine.  Besides the vibration issue, it is very easy to conduct ignition noise (for CD ing engines) or harmonic frequencies (from glow engines) into the servo wire lead which can feed back to the receiver itself and glitch the whole Rx.

I regard to your request for suggestions with the CD cut-off; I alway just picked up a typical 12v switch available at any auto part store, but one with the large flat plastic toggle lever (makes it easier to drill into and ~$3-$4).  I then mount that to the fire wall somewhere ridgidly where it is situated so a (non-conductive) pushrod (e.g. nyrod)exiting the fire wall can toggle the lever.  The servo moving the pushrod being as far away as possible (greater than 4-5") which is very easy to do in a Duck.

By the way, an ignition cut-off is mandatory safety code for IMAA events and possibly AMA sanctioned events too, so I would definitely set it up if you plan to fly at any Fly-In's.

Greg

HI GREG  GLAD TO SEE THE FINGURES WORKING THE KEYS.I FOUND A COMPANY CALLED   WWW.42-PERCENT-PRODUCTS.COM     ...THEY HAVE SOME REALLY NICE SWITCHES FOR ELECTRONIC IGN OR GLO... THEY FLY WHAT THEY MAKE AND SELL.I ORDERED A SWITCH AND SHOULD HAVE IT IN A FEW DAYS...FUDDLOW CANT FLY TIL THE ISSUE IS HANDLED.WHAT A TOUGH PLANE A DUCK WITH 29 LIVES. THE PVC WATER SPRINKLER PIPE  IS FAR SUPERIOR TO A WOOD DOWEL FOR A BIG PLANE BECAUSE OF ITS WEIGHT...I  AM GATHERING INFORMATION ON THE FISELER STORCH LANDING GEAR ASSY...I WILL MAKE ONE BUT IT WILL HAVE TO BE FOR A HIGH WING TO REALLY DO ITS THING.THEY MAKE SPECIAL FOAM TO PUT INTO MOTORCYCLE MOTOCROSS TIRES.I WILL TRY TO GET SOME FOR THE TUBES I LIKE THE IDEA.. LIGHT AND CANT GO FLAT.TO SOLVE THE FLAT TIRE PROBLEM...LEO

I GOT MY 42-PERCENT-PRODUCT KILL SWITCH... AND GOT THE THROTTLE SERVO LOCATED IN THE COCKPIT. I WENT TO A EXTRA LONG SERVO ARE BECAUSE THE CARB HAS A LONG THROW.. THIS SH0ULD GIVE ME SOME VERY SMOOTHE ADVANCE ON THE GAS.. I GOT THE KILL SWITCH IN SERIES WITH THE GOLD PLATED MANUAL KILL SWITCH... AND 42 MAKES THE SWITCH WITH A BRIGHT RED LED LIGHT..WHEN YOU TURN THE SYSTEM ONE IT FLASHES ONE TIME THEN IT ACTIVATES.THE PHOTO CELL KILL SWITCH MUST BE MOUNTED IN THE DARK TO BE EFFECTIVE..(FOUND OUT LATER )I ALSO  HAVE SOME ISSUES WITH THE FUTABA 7C 2.4 GIG MASTER SLAVE SET UP...THE FIRST TIME I TRIED IT IT DID NOT WORK... BUT AFTER SOME INPUT FROM THE 42 FORUMS.. THEY SUGGEST TO SET THE VALUES AT 100%OR MORE IF YOUR RADIO OFFERS THAT OPTION...I HAVE SOME TIME OFF LIKE 1/2 THE COUNTRY DOES AT THE MOMENT SO TOMORROW I WILL TRY THE SET UP HERE AT THE HOUSE.I BOUGHT SOME LAWN  MOWER SHOP OIL MIX . AND THE MOKI JUST PLAIN DID NOT LIKE IT. SO ITS BACK TO MOTOL AND SHINDAIWA MIX,THE MOKI IS NOW HAPPY AGAIN SPORTING 10K RPM AND NO OVERHEATING.ALSO GOOD OLD REGULAR GAS WORKS JUST FINE.IF THE  KILL SWITCH WORKS AFTER THE RADIO ADJUSTMENT. ITS BACK TO THE FIELD WITH FUDDLOW MUDDUCK TO CLAIM SOME AIR TERRITORY.....LAST TIME UP I HAD PIPER CUBS TRY TO PLUCK MY FEATHERS..BUT FUDDLOW WILL DO 360'FLAT TURNS IN LESS THEN 3 FEET. IN SHORT ORDER AND A NICE 20" PROP SCATTERS THE FLOCK BUT PRONTO.IM MAKING NEW STRUTS  THINNER MATERIAL JUST TO SEE WHAT HAPPENS WITH A LITTLE LESS DRAG. IM ALSO LOOKING FOR SOME AIR WHISTLES TO PUT ON THE STRUTS.. HEY WHAT IF I DEAD STICK AT 400 FT HIGH..THEY WILL HERE ME COMMEN AND DUCK FOR COVER.AS ANDREW DICE CLAY WOULD SAY OOOOHHHHHOOOOOOOO ....LEO

Hey Leo,

I would be careful of thinning the struts just to reduce drag.  Drag is what gives the Duck's there unique flight charateristics, but you can always experiment to find the "sweet spot" that is right for you regarding performance/slow flight.  My recommendation to reduce drag would start with covering the bottom airfoil to make it flat bottom in comparison to undercambered.  A fully flat bottom airfoil on a Duck loses some of its very-slow characteristics but gains a lot more performance yet still will slow down.  If you lose too much of that super-slow performance cover only the outer bays so you still have undercamber close to the root.  covering can be Econocote, or while experimenting, just tape (with drafting tape) saran wrap (plastic wrap) in place to test the performance without doing anything that may damage your paint job.  When you get the right mix of what you want, get clear covering for those bays so you don't lose the undercamber appearance or your neat lure paint job!

Greg

HI GREG. MESSEN WITH THE WING HAS CROSSED MY MIND OF FEW TIMES. I MADE ANOTHER SET OF STRUTS TO EXPERMENT WITH WITH 5 LAYER PLY AND SQUARE CARBON FIBER TUBES ON THE OUTSIDES.EPOXY TOGETHER.WITH THE HINGES SCREWED ON WITH SERVO SCREWS. ITS WIDER BUT THINNER BY 1/4 INCH.TOMORROW I MIGHT GIVE EM A TEST..TODAY I FLEW WITH SOME VINTAGE 6" PLASTIC WHEELS WITH RUBBER TIRES THEY ARE 4 INCHES SHORTER THAN THE ENNER TUBES AND VERY SKINNEY BUT VERY STRONG. IT CHANGED FUDDLOW FOR THE A LITTLE MORE TOP END SPEED AND NO EFFECT ON ITS ORIGINAL SLOW FLYING BECAUSE THE DUCK IS NOW VERY LOW TO THE GROUND FOR LANDING.ITS ONLY DRAW BACK IS THE TUBES OFFER WONDERFUL SQUISHEY LANDINGS WHERE YOU CAN SEE THE TIRES SMUSH DOWN.. LOOKS GREAT FOR CROWD APPEAL.BEFORE I FLEW IT I TESTED FOR FULL THROTTLE AND DISCOVERED THE BACK ENGINE COVER ON THE MOKI WAS BLOWING OUT BUBBLES OF OIL, AND AT FULL THROTTLE THE ENGINE WOULD RUN OUT OF STEAM AND QUIT RUNNING... HERE COMES THE GOOD PART.. UNPLUG THE CDI,PULL OFF THE SPARK PLUG WIRE AND THROTTLE ARM AND ITS 4 CAP CREWS AND YOU GOTTER ON THE BENCH.I PULLED THE COVER OFF FOR A LOOK-SEE INSIDE A MOKI FOR THE FIRST TIME,   FULL SYNTHETIC OIL KEEPS THE ENTIRE ENGINE SPOTLESS INSIDE.THERE WAS NO GASKET SO I PUT A LITTLE SYLICONE ON THE FLANGE AND HAD IT BACK IN THE PLANE IN 10 MINUTES TIME, AND PRESTO THE PROBLEM SOLVED.IT REALLY RUNS EXTREAMLY SMOOTHE NOW, WITH TONS OF POWER.A FRIEND SUGGESTED I TRY KMART FOR SOME BABY BUGGY WHEELS MADE OF PLASTIC.WELL ITS HALLOWEEN AND THE 18 YEAR OLDS ARE TRING TO OUTDOO THEMSELVES BEGGING FOR CANDY...(WHATS THEIR PROBLEM) GOTTA GO SHOW THEM THEIR WAY HOME SO THEIR PARENTS WONT WORRY ABOUT THEM.LEO

I am in the process of building my second Agri Duck , my first went down in flames 4 years ago.still have wings and landing gear from the originalkit.
my question is , if any one has seen the you tube Craigs Mud Duck crash  my plane did the exact same thing, how do I prevent this
is it washout required. After watching many videos it appears the low wing duck is less stable than the high wing.
Also Fuddlow I noticed you extended the wings does that help the stability issue

thanks Rayd

Hi Rayd,

  First; I’m glad to see you are building another Agri-Duck;Second the Agri-Duck is less stable than the MkII.  That said, did you follow the recommendations for setting up the ailerons with some reflex (aileron washout)?  The reflex is usually adequate at preventing a wing stall (I'll give details in a moment).

  As for Craig's crash, I evaluated it after viewing several times.  I think the angle that the video was shot masks what was happening at the moment it lost control.  As with any of the Ducks, flying directly at you or being at an angle that is more in front of the plane (or behind) than it is from the side is a disadvantage to the pilot.  These perspective angles prevent up from accurately judging the air speed.  The most common place this presents a problem for a new Duck pilot is making an approach for a landing.  By "second nature" most pilots are very familiar with our "sport" planes that have a "glide path".... Ducks do not have a "glide path", they have a "sink rate".


http://www.mudduckaviation.com/cpg/displayimage.php?pid=253&fullsize=1

  Many new Duck pilots, even knowing that the Duck has a ton of drag and fly slow, revert back to their "second nature" landing approaches and cut the throttle and control the descent to a landing from a relatively high altitude.  What happens to a traditional "sport" plane when you do this is an expected glide path angle of about 20 degrees from level.  When you try this with a Duck at idle (or no power in the case of electrics or a flame out) the duck will want to sink and it is natural to hold the nose up on the plane to bleed off speed, but with a  duck you are only allowing the drag to slow the plane down to a dangerous speed.  the first thing that will happen is at idle (or no power) the plane will slow to a speed that it still flying on the wing but not enough air is flowing over the control surfaces to control it.  Your goal is not to keep the wing from stalling, you want to keep air over the tail so you can steer and correct for elevation.  Once you lose control authority, you only along for the ride, the wing will stall and the plane pretty much falls to earth.

In Craig's video the perspective prevents you from determining how fast the plane is actually moving forward... you can tell the sink rate, but not the actual forward air speed.  Like I said before, we as pilots revert to our "second nature" when it comes to flying... pulling from our past experiences to gauge the present and future.  The sink rate looks fine for a plane that has a flat bottom airfoil, without a ton of drag, but in actuality, the plane was probably traveling very slowly and lost control authority and then stalled.

  The Duck's like to fly into a landing, this is un-natural for sport pilots, the typical result of powering into a landing is a plane that is hitting the runway at 40+ mph and the landing gear looking like it is going to rip out of its belly, not to mention the extremely long runout and the long walk to retrieve it if the engine quits.  In the case of a Duck, though, is that as soon as you chop the power to idle, the plane will slow and stop very quickly.  Just watch the “Intro to the Mud Duck” video.  You will see Tom flying the plane in under power, it even looks like he is doing a slow fly-by then cuts the power about 15 feet before he gets to his position on the runway and then sets down and rolls right over to himself.

  You need to get used to keeping power on when you get near the ground and you will not encounter any problems.  Also, if it is better for you, set your throttle trim as far up as you can,, to the point the plane will not take off, but still have a nice high idle  until you get used to not throttling back all the way when the Duck is in the air.

  With all this said, the Ducks are very simple planes to fly, the biggest hurdle is letting go of your pre-conceived notions of what you expect to happen based on typical sport planes.  People who buddy box on a Duck and never had any appreciable stick time on a sport plane, think it is super simple and easy to fly.  The main reason for this is because if you remember back to your own training or watching new students, what do they do?  They always use too much throttle, especially when landing; Ducks love thrust, so therefore a nervous student gives exactly what it needs.  We as “trained” pilots have been trained or “conditioned” to do the opposite, hence the “un-natural” flying style.

 This may not have been your case exactly, but I would consider it a likely possibility.

  In case you didn’t have the sheet that provided the reflex information  here are the direct links for Page 1: http://www.mudduckaviation.com/cpg/displayimage.php?album=lastup&cat=0&pos=0
And Page 2: http://www.mudduckaviation.com/cpg/displayimage.php?album=lastup&cat=0&pos=1
In case the images do not post .


 

Greg

Hi Greg thanks for your input , I agree ducks are a unique bird ( no pun intended)I think I am going to add  5 deg. up in the alerons as suggested in the first page of the manual, also I think i will program to fly one stick as suggested
question is this new to the manual  I dont remember this included in the original.
also os 108 ,or magnum 91 4 stroke, aremy engine choices, also considering a soft mount motor mount , I will keep you guys updated on my progress

rayd

Greg also many thanks for keeping the mud ducks alive, It i
s about fun and being challenged ,I feel alot of that is missing from our hobby these days , I wish you much luck in your new venture
Rayd

Ray,

  It was added as a suppliment after the fact, but it has been included as a suppliment for quite a while.  I'm assuming you purchased the plans a while ago.


  Although Duck's and the sound of a 4-stroke go together like fish and white wine, for the Agri-Duck I would opt for the OS 1.08 simply due to the power output.  The Agri-Duck requires more power than the Mud Duck MkII to accomplish the same performance and although a .91 4-stroke with fly a MkII around comfortably, I think you would prefer having more power on an Agri-Duck.

  I love OS 1.08's, the power is awesome, and the Agri-Duck will be more fun with it.  I had a GMS 1.20 2-stroke on my last Agri-Duck (probably very close in power to the OS 1.08) and it was a perfect match in my opinion.



Thanks, I appreciate the support and can use all the luck I can get!


Greg