Frank's EP Supersportster re-build

[Frank v B]

An old electric plane magically fell into my car.  Have decided to re-build it.

How it was- it had a geared brushed motor, the red covering was bleached almost white by the sun, the tires were foam but disintegrating.... perfect for a re-build.

Project definition: am going to recover it, install a Rimfire 42-50-600 (Power 32 equiv.), maybe add retracts since I have two pairs of salvaged electric retracts.

Just in case you are wondering why the massive power.  Converting a brushed motor airplane to a brushless power system creates a balance problem.  Brushed motor conversions always come out tail heavy.  Nothing better than increasing the motor size.  On 3 S it would be 375 watts, on 4 cells it would be 500 watts and on 5 cells 650 watts.  Lots of opportunities to fine tune the power equation.  It was originally designed for about 180 watts.

Will strip the covering from the wing so I can add the retracts and re-inforce the wing.

Stay tuned.


Frank

[Frank v B]

Keep going.....

- stripped all the covering off the fuselage, wings and stab.
- re-built the nose and made a new firewall.  The distance was easy to calculate- I put the back of the prop in the same place as the old brushed motor.
- drilled the shaft hole and installed the motor.
- stripped the wing and cut the starboard (right) wing bottom open to fit the retracts.  Method- open up the hole in one wing half, install the bracing, install the retracts, make sure they work, cover the opening, make the wheel well.  Then if everything works... duplicate the same mistakes on the port side and install it the same way.

Note: I went to the centre rib because I want the bracing to get to the centre so I can fibreglass it for strength.

Frank

[Frank v B]

Starting the cowl

To make a cowl removable, there must be a ply back plate to it.  The magnets and registration pins will be drilled into this ring.

- Took a random piece of balsa wood (3/32) larger than the cowl diameter and cut a hole with a Dremel sanding drum until it fit around the X mount, wires and vent holes.
- turned the plane upside down while holding the piece of balsa in place.  Ran a pen around it to roughly mark the perimeter of the fuselage/firewall.

This piece of balsa will be used as a template to cut out the plywood ring.

The outside diameter does not need to be accurate because it is easier to sand when the whole cowl is ready to be sanded to shape.

[Andy Hoffer]

Starting the cowl

To make a cowl removable, there must be a ply back plate to it.  The magnets and registration pins will be drilled into this ring.

- Took a random piece of balsa wood (3/32) larger than the cowl diameter and cut a hole with a Dremel sanding drum until it fit around the X mount, wires and vent holes.
- turned the plane upside down while holding the piece of balsa in place.  Ran a pen around it to roughly mark the perimeter of the fuselage/firewall.

This piece of balsa will be used as a template to cut out the plywood ring.

The outside diameter does not need to be accurate because it is easier to sand when the whole cowl is ready to be sanded to shape.

Very cool Frank!   You can also do this by spreading cheese or peanut butter on the back plate where you want to remove material and leave it out for a mouse to gnaw on.  This method will give much more entertaining photos.  You could even try a time lapse movie series!!     Andy

[Frank v B]

Andy,

re: your "...and leave it out for a mouse to gnaw on."

Like this??


Frank (Who else?)

[Andy Hoffer]

Andy,

re: your "...and leave it out for a mouse to gnaw on."

Like this??


Frank (Who else?)

Perfect!  Aside from a modest focus issue on the first photo, your images are getting better and better all the time!  You are a good student!!    Andy

[Frank v B]

Andy,

re:  "Aside from a modest focus issue on the first photo"

It will automatically be in focus after one beer.   You have obviously been abstaining.

Thanks, Teach.

[piker]

I'm no photographer, but I'd not call that a "modest focus issue"   

But I like the art work.

Robert

[Frank v B]

Making the cowl out of balsa.

- took the 1/16" plywood ring made in the earlier Mickey Mouse photos and made registration pins.  Drilled 3 holes through the ring and inserted dowels.  Then glued balsa onto them and tri-stock in side the corners.
- held the cowl onto the fuselage and planed the cowl to a rough shape with a razor plane
- did some hand-sanding.

Next step- fill the gaps in the firewall and the joint between the firewall and the cowl.  Will fill this with balsa filler.  To make sure the filler doesn't stick the cowl to the fuselage, I have inserted a sheet of waxed paper.  See last photo.

[BJROB]

We saw Franks innovation to strengthening the elevator at last nights TEMAC meeting ... topic ...tools and tips
Epoxy fibreglass wax paper and tape. 
Great tip. 
Super smooth and strong

[Frank v B]

Retracts in the wing.

A bit like putting a gallon into a quart can.

- cut open the wing
- added a plywood brace to the center rib
- glued two rails in place
- installed the retract.

Will let it cure, then make the same mistakes on the other side.

The only challenge will be getting small enough wheels that fit into the space.  We'll worry about that later.  Thanks to our Geotex runway we can fly with small wheels.

Frank

[Frank v B]

One side is done. 

Used smallest wheels that would (probably) work.  Bent the gear leg, added the wheel, then the wheel collar and installed it.  It works!  The next step is to back-fill the balsa around the wheel well.  Once done and tested, the other side will have the mirror image of everything.... including the mistakes.  Remember, as long as everything is done symmetrically, including mistakes, the plane will fly.


Frank

[bweaver]

One side is done. 

Used smallest wheels that would (probably) work.  Bent the gear leg, added the wheel, then the wheel collar and installed it.  It works!  The next step is to back-fill the balsa around the wheel well.  Once done and tested, the other side will have the mirror image of everything.... including the mistakes.  Remember, as long as everything is done symmetrically, including mistakes, the plane will fly.


Frank

@Frank v B , the last time I was flying, I had a mishap.  The wing mistakenly came off symmetrically from each side of the fuselage.  My plane didn't fly anymore. The motor still worked.  The prop went round and round.     Why does your theory not work on my model airplanes? 

I am sure I am not the only one experiencing similar symmetrical mistakes resulting in planes that don't fly. 

[Frank v B]

Bruce,

You're an amateur crasher.  I am professional grade.

Frank

[Andy Hoffer]

Fabulous progress @Frank v B !  Your mouse did a superb job hollowing out the cowling and the wheel wells.

And your photography!! 

Bravo!

Andy