Peppermint Pattie .60 electric conversion and build thread
 

After being away for many years, I got back into flying with a Tower Hobbies EP Kaos.Really nice, predictable flying plane. But boy, are my skills rusty! That plane has a P/W ratio greater than 1, unlimited vertical. So I am going to use the same power for the PP. My original Peppermint Pattie I designed back in 1979, and PP II in 1981. The glow version had a belly hatch to access the radio, etc. With electric, an easily removable top hatch is a necessity. It will go from the firewall to the trailing edge of the wing. This thread will be slow going, I have other modeling obligations from my business, BlueJacket Shipcrafters.

Here's a shot of the 1/8" fuselage with 1/32" doublers glued on.

https://cimg0.ibsrv.net/gimg/www.rcu...a0342cbd86.jpg

So balance is an issue. Ideally you would want the battery on the CG, but it needs to be forward. The Webra speed I used to use weighed 18 oz, plus the magic muffle added 3-4 more. The electric motor only weighs 10 ounces, and the ECU another 2.
So here's where the battery will go:

https://cimg2.ibsrv.net/gimg/www.rcu...0f96cdc855.jpg

The rudder and elevator servos need to go under the wing, luckily they will just fit.

https://cimg0.ibsrv.net/gimg/www.rcu...9715fb67a1.jpg

For those interested, I'm going to be using the Kaos motor mount with an Avian 5055-500kV brushless,a 60 amp ESC, 6 cell 4000mAh battery and an APC 12x10 prop.

So next I cut the outline. Very important to put the stab at 0 degrees. The rudder hinge is 10 degrees.

https://cimg1.ibsrv.net/gimg/www.rcu...83f6d17926.jpg

Hi Nic,
Welcome back! I like e-power, but I’ll never give up flying glow. Following the build and looking forward to your flight report.
I remember your flight demo of the ‘new’ turnaround pattern at the Bridgeport CT. Contest (August of ‘83), a mere 40 years ago. Pattern has certainly changed. You were the NSRCA district rep, too, as I recall.
You might want to post this in the classic pattern forum of R/C Groups, there seems to be a lot more activity there.
regards,
Will Bartlett

Thanks, Will. I remember flying that pattern and learned a new maneuver, the "humpty-bump" Doesn't seem that long ago.....

Here's a picture of my old Peppermint Pattie II

https://cimg2.ibsrv.net/gimg/www.rcu...7bbcfd93d8.jpg

I still have a tube of Ambroid I will use to attach the triangle edging to the fuselage sides.

https://cimg6.ibsrv.net/gimg/www.rcu...4a5aefcb2d.jpg

And here's the left fuselage half, triangle stock all glued in. Notice the wax paper tabs to keep the hatch from gluing to the body.

https://cimg3.ibsrv.net/gimg/www.rcu...e01ebb642f.jpg

Now both fuselage haves are done, here is the firewall and motor mount. Next step is to make all the bulkheads then join the fuselage together.

https://cimg8.ibsrv.net/gimg/www.rcu...313aae967a.jpg

So now all the full-width (3") bulkheads are made. Next step is to mount them on one side, then join the two side together. Alignment is super critical at this stage.

https://cimg9.ibsrv.net/gimg/www.rcu...85da56adb3.jpg

Here's a shot of the wing attachment, it will be tapped for 1/4x20 nylon screws. Also visible just above the triangular stock is the support for the servo rails.

https://cimg2.ibsrv.net/gimg/www.rcu...853bea4e85.jpg

So after a break for the holidays, I attached the three primary bulkheads: firewall, wing LE and TE. Next comes joining the two halves.

https://cimg1.ibsrv.net/gimg/www.rcu...dc81e0d08b.jpg

Fuselage sides joined and connected at the rear. A straight line on the bench was used to make sure it was straight. Next the 1/2" balsa to was glued on. Need to make another 1/2" piece for the removable hatch.

https://cimg5.ibsrv.net/gimg/www.rcu...d6355fecfd.jpg

Installed 1/4" ply retract mount and outlined foam to be cut away

https://cimg8.ibsrv.net/gimg/www.rcu...d97036c130.jpg

Test fit the battery on its mounting plate

https://cimg7.ibsrv.net/gimg/www.rcu...eed053f064.jpg

Installed battery plate with triangle stock. the velcro is epoxied to the plate.

https://cimg2.ibsrv.net/gimg/www.rcu...a2c9c86cec.jpg

Also put in support bracing on the other(top) side of the plate to secure it.

https://cimg5.ibsrv.net/gimg/www.rcu...42afbaac01.jpg

Now the rest of the top blocks have been added. Time to take out the plane, angle grinder, orbital sander, etc.

https://cimg7.ibsrv.net/gimg/www.rcu...6662f9be1c.jpg

Used a 4" blade foam cutter from Hot Wire Foam Factory to make the cutouts for retrcts and aileron servo. The tool was really easy to use.

https://cimg2.ibsrv.net/gimg/www.rcu...07e8c3a94e.jpg

So those big blocks are starting to take shape.
https://cimg6.ibsrv.net/gimg/www.rcu...be3062de20.jpg

The top blocks are rough sanded to final shape with 60 grit sandpaper. Automotive putty filled a little gap.
https://cimg2.ibsrv.net/gimg/www.rcu...40568dc397.jpg

Next is a big step - cutting the access hatch free from the fuselage.
https://cimg7.ibsrv.net/gimg/www.rcu...c6b672dcb2.jpg

A few more facts and figures:

wingspan 66"
wing area 690 sq in
weight 8 pounds
speed 100-110 mph