BackyardRC

A practical approach to RC planes

Rat Rods of the Sky

The Rat Rod look has been around for old cars for a long time... but what about on a plane?

The Rat Rod look has been around for a long time… but can it be applied to an RC plane?

Over the past 10-15 years there has been a new cool in hot rod cars. The rat rod. This style of hot rod or custom car  imitates (or exaggerates) the early hot rods of the 1940s, 1950s, and early-1960s can be characterized by some as mobile junk. Most rat rods appear “unfinished”, regardless of their status, as only the vehicle’s bare essentials are driven. I for one love the rat rod look, culture, and ethos. Start with an old shell of a car from 70 years ago and do the bare minimal to get it up and running. While repairing, the goal isn’t perfection or even finding the right part but often simply using what you have in a creative way. And this all begs the question for me. Can’t this be applied to RC planes? I am a member of my local AMA RC Club (Keystone Radio Control Society) and we have a table at our field where anyone can drop off old used RC parts, planes, gadgets for the next guy to pick up for free. And lately there have been a number of damaged planes dropped off. Often crashed, stripped of all useful parts, and given up on by the previous owner. This is where my idea of Rat Rods of the Sky comes in. I’ve been picking up these old vintage (and some not so vintage) wrecks, piecing them together with whatever I have lying around the shop, and then flying the tar out of them. This past week I found slightly used Piper Cub (I think J3 but correct me if I am wrong). It had just a few minor dings and dents, a few holes in the monokote, and was missing the servos and motor. Oh yeah and it had been nosed in at a good rate of speed and the whole nose was smashed to bits. But the wing was in good shape. The tail straight and solid. A perfect rat rod candidate. So I took my new patient home to the shop for some much needed surgery.

Piper Cub Rat Rod Starter Kit

Piper Cub Rat Rod Starter Kit

The first order of business was simply assessing the damage and stabilizing the nose. I simply took all the smashed balsa and recreated what I could like jigsaw puzzle of tooth picks and kindling. By the time I had glued a few sections back together the nose was solid and straight. Ugly yes, but a good foundation to build upon.

Nothing a little guess can't fix

Nothing a little guess can’t fix

It's nothing more than a jigsaw puzzle!

It’s nothing more than a jigsaw puzzle!

The next order of business was to start planning the conversion to electric. I knew I needed to find an easy way to load and unload a battery, mount the motor, and all while working toward a proper center of gravity. I have a bunch of old DT750’s around from my first tricopter build back in 2013. These cheap bell style motors with there long shaft, wide mounting plate, and efficiency on a 10×3.5 slow fly prop made it the perfect candidate for the conversion. Being significantly lighter than any nitro or gas motor that was previously in this plane I new I needed to more the motor as forward as I could and then balance the plane with the correct battery placement. Using some old 3/4 wood booms (also off my old tricopter) I built a frame to strengthen the nose. The large booms also helped sneak much needed nose weight up front.

Subframe Goodness

Subframe Goodness

The new subframe and firewall are rock solid

The new subframe and firewall are rock solid

Once  the subframe was glued in I hand cut a firewall and deck for the battery to Velcro to.

Battery Tray

Battery Tray

At this point the airframe is rock solid and more or less complete. Yes it’s not beautiful, but it is functional. Any more work to the fuselage would just diminish the character of this old bird. To mount up the DT 750 I decided to go modern and 3D print a mount.

3D printed DT750 motor mount

3D printed DT750 motor mount

3D printing had become such a staple for me in any mounting of motors. 15 minutes of CAD design and I have the perfect alignment and placement of the motor. It lines up centered in the cowling, perfectly aligns with the center line of the plane, and has the perfect offset. If you would like a copy of this mount for yourself you can find the print files over at thingiverse.com or you can order a print from me over at 3DHubs.com.

Download the CAD and STL files over at Thingiverse

Download the CAD and STL files over at Thingiverse

At this point I’m well on the way to having the Piper Cub Rat Rod flying be the weekend. But there is one hold up: I am out of stock of spare servos. Guess I have been building too much this winter. So until my HK order arrives the Piper will be hanging out on the bench.

Piper Cub Rat Rod

Piper Cub Rat Rod

Let’s hope the servos come before the weekend! I’m dying to fly my new plane! Thanks, Miles

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