I'm flying an E power Predator that now weighs 68 oz (with 6S battery installed)  I ended up with 2.5 oz nose weight.  The construction is very similar to what Paul Walker was using several years ago.  I cannot speak to his current practices.
 My limited experience indicates:
•   IC Aerodynamics are fine, but I have not done experiments.
•   E-power CG wants to be way further forward than same IC airplane. 
•   E-power lead out exits want to be way aft. My LO exit center is 2 ¼ ” aft of the C.G.  I am not alone in this.
•   E-power control system friction must be near zero. The IC vibration breaks up the friction, thus IC can handle more friction.
•   I use similar nose construction as IC. 3/32 balsa fuse sides, 1/64 ply doublers, and molded top and bottom blocks. The fuel tank area has spruce rails (upper and lower) to accommodate battery mounts.
•   I use a balsa/plywood radial motor mount.  The motor is cantilevered (mounted on its rear surface).
•   I use same finishing methods as on IC.  Auto urethane clear over an all-dope substrate.  I like that it is impervious to everything.  Your E-power model will likely see glow exhaust in its lifetime.
•   I notice that my flying lines stay MUCH cleaner.  I now believe the schmutz we clean off lines between flights is almost completely due to glow exhaust residue.

One great benefit of E-power is the utter consistency of the motor run.  It allows one to better evaluate small trim changes without questioning if variation in the motor runs is playing a role.

Hope this is helpful

Hi Doug,

You might want to read an article that I wrote entitled, "Turning to the Darkside - The Building of Circulas 46 IIe".  It about design, building and trimming my first electric profile. The article can be found and downloaded on the Flying Lines website at: http://flyinglines.org/nunes.circulas46lle.html

BTW, Circulas 46 IIe finished in the Top 5 in Advanced (4th place) at this years AMA Nationals.




Dennis

In addition to all of the above, the electrics allow you to move the battery up/down and fore/aft to achieve static trim previously done with lead weights and other old-fashioned tricks like heavy spinners and light wheels.  The challenge is to design the nose section in such a way that it allows:
- Motor mounting that allows easy outboard offset adjustment;
- Easy battery re-positioning;
- Secure battery mounting (battery ejections have been reported by some);
- Fast and easy battery replacement to save time during practice;
- Provides for optimal airflow to cool all electrical components with minimal drag losses.

I've seen solutions that achieved some of these goals, but not sure about all.

How about some pics of how the motor is mounted and the nose is constructed.  I searched but the search didnt show many much.  I know it has to be on here. If you have links or pics let me know.

Thank you
Doug

Here are some shots of the firewall.  Again, I did not invent this, I learned from Paul Walker.
•   3/8” balsa core
•   1/32 ply on both external surfaces
•   15/32 dia hardwood dowels in the balsa at the 4 bolt locations
•   4-40 blind nuts.

The spruce rails use 2-56 blind nuts and fasteners.

BTW - The Crist Rigotti build referred to by Dennis is magnificent.  Kudos.

Here are some shots of the firewall.  Again, I did not invent this, I learned from Paul Walker.
•   3/8” balsa core
•   1/32 ply on both external surfaces
•   15/32 dia hardwood dowels in the balsa at the 4 bolt locations
•   4-40 blind nuts.

The spruce rails use 2-56 blind nuts and fasteners.

BTW - The Crist Rigotti build referred to by Dennis is magnificent.  Kudos.

I used this mount on my last one (Endgame).   Notice how much room there is behind the firewall.  It also puts the motor wires out of the way which is always a problem with a front mount and the best part is that you use a prop adapter instead of the always pain in the a** collett.

Nose strength comes from the battery tray screwed into the side rails.  It is like a former only horizontal instead of vertical.

Ken

Here is my two cents. They will probably twist everything you expect to hear but this is my logic. Talk to Richard Oliver, Joe Gilbert, Matt Colan, who flew my model and see what they says about it. Everything I have implemented in my model build is proven. Actually in the last trim it was even better than when they flew my plane. 

Nose/tail moments?
Does your CG usually end up further forward than a glo setup?
Whatever you use now for tail moments will work but for myself I found out that if I move the elevator back 1-1.5in you will be much better off.
Nose moments are about the same. The motors are lighter than the IC option but the batteries are heavier than the typical fuel tank so overall the weight distribution will migrate aft slightly.
Moment is mass timed distance from CG to center of mass. If you do the math you kind of break even. Keep the prop in the same position as you had it before and allow the battery to slide forward and back to finetune and change CG.

Is the stab elevated or is inline better and why?
It seems that both will work but the in line my be harder to achieve. Some swear at them some swear by them. But the staggered  setup may be friendlier and I would argue that the tracking is better because the elevator is in clean air. The later one is my go to standard. By the way I have dihedral in my stab to push even further up in clean air.

Is a typical, say  Geo Bolt wing, and good starting point or is the airfoil different, thinner?
I have a clean airframe on my bird. 18% at root 16% at tip. I could have gone even thinner than that with no adverse effect. The idea is that the electric powerplant is easy to control and the motor will not surge or runaway. I like it because the model penetrates very well in the wind plus the power consumption will go down too.

And does the line rake end up further aft?
Fly test and adjust. In IC configuration the CG migrates as the fuel is consumed, that is not the case in electric.

How is nose construction different from a typical beam mount system?
Just use 1/64 doublers and you are good. Maybe use another patch of 1/64 ply 1in wide where you mount the motor but other than that not needed. Allow air to flow around the electronic parts to keep them cool. I don't like rear mount because it stresses the motor more than a front mount and if that was not reason enough to front mount you have to add a prop adaptor which adds weight too.

Other things to consider are: A big motor means smaller battery smaller ESC better efficiency less wasted heat. Electric motors have lots of torque, are most efficient at 0 rpm and least efficient at max rpm. So therefore big diameter higher pitch than what you are used and lower rpm setup will benefit efficiency and corner (less gyro precession).  As Voltage goes high Amps go low heat goes low. 

For a 60 size I would consider 2B 12x6 12x7 13x6 13x7
https://innov8tivedesigns.com/badass-3520-560kv-brushless-motor.html on 6S or 
https://innov8tivedesigns.com/badass-3520-650kv-brushless-motor.html on 5S
https://innov8tivedesigns.com/badass-3520-790kv-brushless-motor.html on4S 
 
 

What springs to mind with the use of electrons is the divorcing of the fuel cell from the powerplant, the ease of prop direction change, use of multis and their synchronised cut offs, no need for a muffler so side mounted ones that spoil looks are a thing of the past.
Pusher designs are easier, same as counter rotating.
Negatives, audio - nothing sounds as good as a 4/2 switch.

Here is some advice you WONT get.

Dont stress about moving to electric. Both Dave and Joe Gilbert had piped ships that performed AS WELL at the job of penetration and speed control.
Paul and Orestes were both electric and I would assert put in hundreds of hours of preparation.

Your "Doug Moon" approach was guided/mentored in principle by someone whom dominated the sport. You personally have evolved over the last 20 years to have a setup that is proven to be Nats Win quality.

My advice, dont feel your loosing ground to anyone if you decided over the next 10 years to build ONLY your "Moon" system IC ship.

There are only 3 things needed to win.

Well trimmed bird.

Lots of practice,

Reliable power.


Electric isnt "better" its just different. 
I see where your coming from. You dont want to be "left behind" or "Loosing ground to the field"

Trust me as someone with ZERO vested interest, what you have is more than enough to get up there again.
You have great experience with your systems, USE that expertise and just fly WAY more..  ( 200 flights a month ) will yeild more improvements than stressing over the questions your posed here.

Hi Doug,
There is lots of good advise in the above posts.  But I keep thinking there is much to learn about design and procedures to wind up with a winner!  For example the longer tail moments are good advise, the chunk of lead in the nose (battery) is heavy and needs to be designed around to achieve the proper CG (what ever that is). Tail group size, past experiments has shown that 25% of the wing area (for flapped models) to as much as 28%.  Any more that that and it starts looking like a “Flying Flea” in my opinion.

Construction should employ the use of Carbon Fiber laminated between balsa and plywood to keep the weight reasonable limits.  Most of us don’t have access to mils and to CNC to build molds, so we depend on the old methods of balsa and plywood with some laminating a few parts with CF. 

Airfoils are a good place to start I think to improve performance on electric models.  The old 18 to 20 airfoils were great, but I’ve been using a thinner section (below 18%) and they seem to work just fine, not sure how low I can go yet, but time will tell, I’m hoping for as low as 15% section will work out maybe a little lower like 14% root, and the tip section of 15% with a flapped wing.  Lots of things to try that’s for sure.  But keep in mind all that we have learned over the years, about what did work, and what didn’t and make changes in areas where we can see and feel the improvements.  And yes, I have a few ideas about building fuselage with molded 1/16” balsa fuse sides with laminated CF.

Later,
Mikey