50% Scale FT Explorer

I wanted to build a plane for my dad for his birthday to help him get into the RC hobby. He really liked the 3D printed FT Explorer that I did but thought that it was too big and wanted something smaller. I also really like the design of the Explorer, since I’m still learning to fly and it’s harder to break props on a top mounted pusher, but it is pretty darn big.

I am actually planning on designing 2-3 pushers based off of real world planes but that’s gonna take some time. On the other hand, setting the printer¬†(2D, I feel weird having to specify this, but it seemed necessary) to 50% is very quick and easy.

I won’t go through the steps of building the aircraft since there’s already a great article and video¬†on FliteTest’s website, but I do want to talk about a few things that come up when you scale down these plans.

The biggest issue came when I started to assemble the parts I cut out. You see, when you print something out at 50% scale your material doesn’t scale down as well. When there were elements such as slots that were designed for ~5mm foam board I had to widen them in order to make things slot in well. Unfortunately I didn’t realize this at first and the building process took a lot longer than it probably should have and also didn’t end up very clean. Another issue was the weight. Even though there was less material it wasn’t half as much material so it’s a little heavy overall. The last problem was the motor. I used a leftover Gremlin motor (1104 size) and that was wayyy to underpowered. I’ve since gotten a 1407 size that should do much better.

With the weight issue and general uncleanliness I’m planning on rebuilding before I give it to my Dad. I have a few ideas such as building at 75% or trying 50% again but removing the paper from one side of the foamboard to cut down on weight. I’ve also thought about altering the plans to account for the double width material but that might just be too much for me at this point.

2 thoughts on “50% Scale FT Explorer”

  1. Thanks for the write up. I’m in the middle of a 50% build of the ft explorer.

    I already considered the thickness of the board and I am widening the outer parts to fit. This definitely adds to the build time and a micrometer/ruler is a must.

    As for the weight, I was considering an inch longer on the main wing and half inch wider on the tail wing. This would add a little more lift without too much trouble. It should end up more lift efficient but have slightly less roll authority. As a trainer, I don’t think this will be a big issue.

    I’m going to throw on an mt1806 motor since I have plenty laying around. It may be a bit overpowered but you can always throttle back.

    I’m also concerned that my 5″ props will strike the tail. I may reshape the motor mount and redirect the prop to not induce nose diving with a high prop.

    Did you finish the 50% build or try a 75% build? I think it’s great that you are getting your family into the sport.

    1. Thanks for the comment!

      Good idea changing the dimensions to alter the weight/lift, I hadn’t considered that! I was thinking about actually rebuilding with poster board using foam board for the spar and tail boom (for a little extra rigidity) but other projects have taken priority since it’s too dang cold to be outside right now haha

      I think you’ll definitely need to change the thrust angle if you raise the motor to account for a larger prop, I noticed that everything was quite a bit more sensitive at 50%.

      I might revisit this project this year but I have 2 pusher designs that I want to try my hand at doing from scratch. We’ll see!

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