Community Junkers JU88 - Build Log

This community member has built a JU88 using everyday water bottles as engine pods! Check it out.

Inspired by seeing a verity of airplane engine-shaped beverage containers in the grocery store, Bill Stephenson thought “some of those would make good/cheap engine nacelles for an electric project”. I talked with Bill about the project he then constructed. Here’s a build Log.

————————-

Specs:

First, if you want to know more about the details of this warbird, here’s a numerical summary. 

• 59” span
• 1022 grams/35-1/2 oz. all up weight with a 3s 2200 battery
• 4x 9g servos
• Flite test power pack “C” (w/ Emax 2213-935 w/ 20 aH ESC) (one BEC disabled)
• 8 x 4.5 counter rotating props
• 104 watts per motor with 12.6 and 8/4.5 prop. (200+ watts, 16+ amps, total) full throttle

—————————-

It all started with the engines: “I found and used the Smartwater™ brand because it had a smooth bottom with no dimples. At 73mm it was just the right size to fit a power pod size box.”

Deciding on a model was the next step: “The Ju88 was my choice because its conventional tail and rectangular fuselage made for ease of construction.”

“The size/scale of the plane was base entirely on the the diameter of the water bottle nacelle. The three view that I used scaled the nacelles at 10mm, so all dimensions were taken from the three view were multiplied by 7.3 (73mm diameter water bottle) and drawn up to scale. I changed some outlines for ease of construction.

“The horizontal stab was reduced in width, the wing plan was straightened a little. The biggest departure from scale was the the front of the fuselage. The scale version starts to taper at the leading edge and continues to the nose. 

I kept it a straight sided box (again for ease of construction) up to the front of the canopy and tapered it abruptly. As a result, the top view is bad, but the side view is passable”. - I’d say from every angle that this airplane looks just great!

To create the rounded canopy and nose, Bill used a block of styrofoam band sawed into a rough outline and block sanded. 

“I sealed the foam with some latex house paint and sprayed a finish coat of Rustoleum rattle can spray paint over the whole the whole airframe, (green on top and blue on the bottom), and Tamiya acrylic was airbrushed on for the camo and graphics.” 

“The canopy/nose block foam was masked with thin strips of blue painters’s masking tape (for the canopy frame mullions) and sprayed out gray. The shadows around the mullions and panel lines are airbrushed Tamiya smoke. Panel lines are a Sharpie pen”.

Q&A

I asked Bill some questions to gain a closer insight into the way he works and how the model came together. 

Q. What was the most difficult part of the build?

A. “The most challenging part of the design/construction was modifying the airfoil to a Clark-Y from the traditional Flite Test two fold at the spar design. I printed out some wing ribs in the correct size for a few spots in the wing and hot glued them in place in front of and behind the spar. I creased the wing top every 1/2” or so to get a gradual bend to follow the rib shape.”

Q. What electronics and materials did you use?

A. Electronics are per specs above. Material is standard 3/16”/5mm thick dollar store paper faced foam per standard, with some light ply reinforcement.

Q. How did the maiden flight go for you?

A. The maiden flight was conducted on my favorite slope soaring site (so I would have some altitude below me (which I used). I was nervous (naturally) about crashing on the first toss with all the detailing I had put into it. It trimmed out and flew well. Subsequent underhand launches on a flat field were very successful with a nice straight climb out.

Q. What are the flying characteristics of your JU88 like?

A. Flying it is a dream. No bad habits. It slows down and cruises at half throttle. Very quiet. Everyone at the field comments on how quiet it is. It slides in for a nice landing on the nacelles.

Q. Do you have plans?

A. Unfortunately, I did all my drawings “old school” so I don’t have an easy way to share the plans with the community. I think that someone with CAD skills could puzzle through my work and figure out a way to get this out.

Bill’s JU88 is certainly a wonderful community creation. If you’d like to see more community builds featured on flitetest.com, you can email this address with suggestions or your own projects.

[email protected]

Keep flying high!

Article by James Whomsley

Editor of FliteTest.com

Contact: [email protected]

YouTube Channel: www.youtube.com/projectairaviation