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Martin Mars sea plane


Junior Member
Well, here I am diving into a plane design, having built a grand total of one FT Swap-able (FT Racer) but totally digging the design philosophies of Josh and Co., as well as all the other builders here. I usually don't start with something easy, so I chose the Martin Mars seaplane, a big, 4 engine transport from the WWII era. I just kind of got to sketching, and all of a sudden, a plane started to emerge. Here are some pictures of the design work so far. Wingspan is coming in at 108.5 inches (I know, weird number, just is what it is). No idea's yet as far as what kind of motors, esc's, etc.

Martin_Mars.PNG Martin_Mars_update_1.PNG Martin_Mars_update_2.PNG Right_Wing_Shape.JPG


Biplane Guy
Cool, nice work! Are you planning on flying this thing off of mighty mini motors? I think that you could probably get a 60"-70" wingspan if you used 250 racing quad motors.

I remember watching a great documentary on the last surviving Martin Mars seaplanes, when I went looking for it, I couldn't find it, but found this:

a little progress

I was traveling on business for a week, so haven't been able to draw much. Here however, is tonight's update. It doesn't look like much, but a lot of detail work is going on. I have added the engine nacelles general shape, put the skin on the wing, and spent a lot of time making the fuselage line up across all the components, and also figuring out how to tab and slot everything so that all the parts align correctly. Some adjustments will still need to be made. Once I draw up the horizontal stabilizer, I can start to figure out how to place all the parts on 20x30 foam core boards.


Looks very nice. Are you going to provide plans after you are ask done?
of course that would be the plan, but we all know how life goes. It is becoming more and more apparent to me that I have taken on a beast, but I will persevere. There is a lot of redrawing involved, as the over all shape emerges.


Well-known member
Love this plane. I grew up in BC watching it fly. Last saw it fly about 5 years ago as it filled from Slocan Lake. It flew over our heads and the end of the lake spraying us with water dripping from the airframe. Sounded like 1000 Hell's Angels. Also saw it dump on the ridge above my farm. Watched it fill from Christina Lake on several occasions to fight fire on both sides of the border.

Wondering if anything ever came of this as I've decided it's on my build bucket list. Not tomorrow but when I acquire more skill with building and designing. I've never used CAD.
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