Mud Duck Aviation Forums

I am close to finishing a Mud Duck but I have used a two cylinder four stoke .90 Satio engine, added nose wheel steering, added a home made glow driver system and modifed the main wheel suspension. I may have over done it.  The quacker wieghs in at about 19.5 pounds.  Can anyone let me know what your finished versions have weighed? 
Jim / Las Vegas

She'll fly at 19 pounds but she may be a bit sluggish.  Typically the full up weight averages around 15 pounds.  It sounds like you put all sorts of bells and whistles on yours. 

I couldn't help but focus on "nose wheel steering" in your post. is this to say you made yours a tri-gear?  Do you have any pictures?  A nose wheel was attempted a long time ago but it never got off the ground.

Greg,
I will get some pictures this weekend as it is currently hanging in the garage.
I was also thinking about making a little larger wing to reduce the wing loading but then I would need to widen the main gear width as well.  Thanks for taking the time to reply.
Jim

Greg,
Here are a few pictures, sorry about the size but I had to reduce them in order to get them down to size.  If you would like better pictures I could send them via e-mail.  I built the "Duck" with the rudder and elevator servos in the cabin.  After trying to balance the aircraft I found it was tail heavy.  I decided to add nose wheel steering in order to offset the balance weights.  I then decided to add a glow driver for the engine as well since it was still tail heavy.  The engine servo, glow driver micro switch and batteries (2C-cells) were also put in the cabin area.  Since the aircraft was still some what tail heavy I moved the engine servo and glow driver micro switch into the fuel bay and the glow driver batteries into the lower forward fuselage opening.  The aircraft then balanced without any addition weights.  After reading your comments, I am afraid the "Duck" might be a little reluctant to take to the wing and fly slow and easy.  It might be time to redesign or try to fly and start over if weight exceeds lift and drag exceeds thrust.
Jim 

Hey Jim,

  It's worth giving it a shot and see what she flys like.  The Mud Duck Sport built from the kit comes in at between 7#-8# typically, but I have one that is 11# over 30% heavier and she still flies okay, just not as much fun as a lighter version. You are only about 20% heavier than the typical AUW, and since it is a full-size Duck the scale aspect would dictate that a MkII 20% heavier should still fly better than a Sport that is 20% heavier (air molecules don't scale).

  I am more concerned about your ability to take off due to the nose gear.  I think your set-up is very inovative, simplistic (as all Mud Duck things should be), and most importantly "neato".  But based on Dan Thompson's tests in the past he couldn't get his to rotate and it stuck to the runway.


http://www.mudduckaviation.com/cpg/thumbnails.php?album=19&page=2

I haven't attempted it myself due to his progress reports, but to quote the NY Lottery: "Hey, you never know".

I really like your color choice!  I will be building some more Demo models and was considering some new color choices and I think you just fixed my indecision. Of course, I am keeping the MkII the trademark "yellow" but I wanted to roll out a new color for the electric version.

 I also see in your photo that you did something to the main landing gear.  Do you have any close ups of that?

Greg

Greg,
Here are a few pictures of the main gear.  After I put in the nose gear and worked out the balance issues I found that if the aircraft was rotated tail down past 25 to 30 degrees it would fall onto the tail.  I first tried just taking the main gear off and turning it around.  That helped but the aircraft still would fall onto the tail when moved down.  I tried a couple of things and then simply moved the axle further back, made each gear move independently (with a common fiberglass rod axle) and pivoted each gear about the axis where the original axle would have been.  This also put the axle of the rear mains approximately 5.0 inches aft of the wing CG.  The aircraft will still go over onto its tail but must be rotated past 45 degrees.  This is why I left the rear tail wire in place.  As for being able to rotate on take off,  I have yet to get up enough nerve to take it out try it.  The height of the nose wheel was set to give the wing a slight positive angle of attack when setting level.  I thought this would help in getting the weight off the nose as soon as possible.  The nose gear should be pretty sturdy.  It is made from an oak dowel, 1/4 X 1 1/4 inch wood strips and plenty of Gorilla glue.  I drilled a 2 inch hole plywood deck behind the engine and put a lite plywood filler onto the wooden braces in the bottom of the fuselage.  On the exterior bottom of the fuselage I placed the same size wooden strip and screwed that to the lite plywood filler inside the fuselage.  That allowed the stress of the nose gear to be placed onto the entire bottom and sides of the fuselage.  I then painted the interior of the fuselage to prevent fuel damage and covered the hole in the engine deck with lite ply wood.  I drilled through the bottom wood strip up thought the rear engine deck and made a couple of plastic bushings for the oak dowel to pivot in.  The steering arms are a single piece of .032 grade aluminum fixed to a rubber grommet which presses over the oak dowel.  This allows me to be able to remove the nose gear if needed.  If flying it turns out to be as much fun as I had building it, it will be a dream come true.   

You definitely got creative on that entire landing gear setup!  It is reminiscent of a (Mud) Duckified jet fighter landing gear system without the retracts (eleo system).