March 16, 2019

Hi everyone,
This the start of a new build, well...I’ll being catching up, to where we are at this point.

This build is the collaboration of several people which without their help this complex endeavor wouldn’t have been attempted.

The XP-67 was a prototype long range fighter escort developed during WW2, it was expected to be very fast while carrying six 30mm guns. Unusual in design it challenged the limits of knowledge at the time by being a blended wing aircraft, in other words the entire aircraft was an airfoil, wings, nacelles and fuselage which though different sizes were blended together in the effort to eliminate drag. The airfoil was the same as used on the P-51, a NACA 66.

The model’s overall WS is 120”, a little smaller than what I have been building,  the limiting factor was sizing of available components, motors, props, retracts, wheels and etc. the fuselage is about 98” in length and about 24” at its widest. Each nacelle is 54” long by 16”. Two 50cc electric motors driving 4 blade 24” props.

All this adds up to a very large airplane when assembled. To make it feasible to transport it’s broken down into 5 parts, fuselage nacelles and outer wing panels.

My ability to use CAD is nonexistent so I’ve relied on two very generous guys to aid me. The first is the talent of Chris Holtorf a retired CAD wiz who spent hundreds of hours taking the few available photos and various 3view drawings turning them into 3 dimensional computer drawings. The second is Jim Schroeder who took Chris’s drawings and drew the internal structures and formatting them to be laser cut. Jim has invested a lot of effort in supporting my builds, the Blackburn Beverly’s wing and it’s beautiful working landing gear, the CAD work on the Mars plus the machining of so many parts to make it feasible. Gerry Bertrand  and Dave Blaby of Vancouver BC who are providing their talents CADing and printing (yup...3D printing) the wheels for the Moonbat.

Click on an image to open it in a lightbox.

April 6, 2019

Lately while I’ve been waiting for supplies I’ve been puzzling on how to plank the forward edges of the fuselage and nacelles, the curvature is quite large so the planking can not be curved enough to capture the shape. I ordered several planks of contest balsa to be cut and fitted between each former and rib. After they are all glued in place my intention is to shape them then glue a ledger board on the rear vertical portion to glue the front of each plank to thus alleviating the bulk curve for the plank.
The flat area behind is 1/8” birch ply GG’d to spruce stringers that forms the floor of the battery box.
April 14, 2019

Exciting day as I received an email from Dave with a photo of the finished wheel set for the Moonbat! Dave and Gerry generously offered to design and 3D print scale tires and hubs.  Often it is difficult to source items for one off scale projects because of unusual dimensions and looks.   Before Gerry offered I hadn’t thought of 3D printing such an item.  They should look spiffy and very scale like on the airplane.

September 2019


Finally the building season is here!  Taking a break sometimes gives me a new perspective on the project and I see mistakes I’ve made and dead ends I’m headed for.


But first, I installed the flap servos which originally I was going to place back against the center longerons  with a pushrod going rearward to a bellcrank pivot on the longeron. A fresh look caused me to place the servos in a more service friendly spot reachable thru the battery compartment. A carbon fiber tube will run back to the bellcrank then down to the flaps.

The nacelles are now held to the fuselage by two 6-32 screws placed inside the battery compartment to blind nuts in each nacelle.


One problem I caused for myself was placing the motor mount holes too far apart, the only solution I could figure out was to glue a new mount ring on the back side of the firewall with the proper spaced mounting holes. Somewhat easier said than done, using my Dremel tool with a carbide bit I ground thru the firewall to make room for the motor mount then used the original blind nuts to screw the ring to firewall while the glue cured. Probably I’ll have to use some small standoffs to place the motor in the proper position for the props and spinners.


All of the perimeter banding is now secured to the fuselage and nacelles, I’ve started cutting in spruce stringers to reinforce and spread the loads from the nose wheel to the fuselage. Once the top is planked more will be placed on the bottom before it’s planked too.

October, 2019


I thought I’d give you a quick look at how I roughed out my stabilizers. The left photo is the location the spars/shear webs and the horizontal stab mounting box. I went thru several designs before settling on this one. The main issue was to design the vertical stabilizer to be strong enough hold the mount for horizontal stabs. There are 4 spruce spars that are placed vertically from both sides of the keel longeron up thru the center of 3 ribs.  The stab mounting box will be placed between the second and third ribs locked in by the spruce spars.  All the wing spars and the box mounting spars will be shear webs so I think it will be strong enough.


The right drawing is the same except cleaned up with a vertical rib sample. This drawing is for Jim to use as he puts the ribs into cad to be cut.  For those wondering the airfoil for the stabs is a NACA 0012. The control surfaces will be fabric covered just as in the original.