I cut, and sanded the motor rails in half. They are longer than I will probably need. i wanted to see the motors before I design the motor mounts.

Originally Posted by kevin matthews

The motors.

Can you place one of the motors next to one of the nacelles? They look very small.

Originally Posted by kevin matthews

I'm thinking of cutting off the undercarriage wires at 1/2", and attaching lighter wire.

are you thinking about splicing the gear wires with a smaller gauge wire? I would leave gear the way they are.

Ken, Yeah, I have been thinking of using smaller gauge wire for the wheels, but if you think I should keep what I have I'll do it. I'll post pictures of a motor next to a nacelle later on, I just got up for the day.

Ken, here ya go... I appreciate you following along. Are they too small?

The rudder perimeter. It's double wide but will be sanded to a pointed edge. For the nacelle sections which are over / under the wing I might make them with 1/32" sheet. I'm going to make a paper model to see if that's feasible. I'm either going to sheet the nacelles from the LE to the motor, or tissue rather than use the plastic parts.

Originally Posted by kevin matthews

Ken, here ya go... I appreciate you following along. Are they too small?

I'm not a expert but don't think they are going to have the power for this quad motor B-17. I have not built many models but what I do is start with the battery. I think you will end up with a weight without receiver and battery of 35 to 40 oz.
I weighed mine a couple of years ago but can't remember were I wrote it down! It was somewhere in that range, I need to take it off the wall and weight it.
Anyway, I think you will need a minimum of a 3s 1300mah batt and that only got me a 3 minute flight ! I got out the file on the Guillows B-17 (thank you for making me get it out ) and looked at a few notes and plans. My batt weighed 3.7oz and battery technology has improved since then so lighter may be possible. I just finished and maiden the Guillows PBY that weighed 17oz before batt and I used Detrum BM - 2800A 810 KV motors that is the same batt as the B-17 I would say I could go with a slightly smaller power system.
Try and place the electronics as far forward as B3 as you can, it's a big a## bird, it will help with the CoG .

If I knew the maximun weight four of the motors I have will work for I can go from there. Ken, did you discover the CG is right at where the plan indicates for C/L?

My CoG was 21.5 MAC and I think it could be a little more aft.

Sounds like around 25 % back from the LE at the root. That's exactly what Andy Lennon calculated for RC planes in his book.

Bruce said a total weight of 16 oz would be okay.

Originally Posted by kevin matthews

Bruce said a total weight of 16 oz would be okay.

That would be great!

Ken

Here's the rudder:

Originally Posted by kevin matthews

Sounds like around 25 % back from the LE at the root. That's exactly what Andy Lennon calculated for RC planes in his book.

That's a starting point and relies on a lot of things on the model. Far better to input the data from measurements into one of the online CG calculators. Something like this one;

http://adamone.rchomepage.com/cg_calc.htm

And odd though it sounds put in 5 (%) for the stability margin figure.

Originally Posted by kevin matthews

Here's the rudder:

Very nice work! What did you use for the rudder hinges?