You have a narrow wing cord...so you don't have much leeway to balance.
How wide is your wing front to back (this is the wing cord).
Shoot for a CG 25% back from the leading edge.
If the wing is 5" front to back... the CG should be 1.25 inches from the leading edge.
If the wing is 6" front to back... the CG should be 1.5 inches from the leading edge.
If the wing is 7" front to back... the CG should be 1.75 inches from the leading edge.
Draw a little pencil mark back from the leading edge on the bottom of the wing on either side of the fuselage where the CG should be located.
You can extend the pencil mark to the bottom of your fuselage.
Mount the wing where you designed it to be mounted.
Balance to the pencil mark by moving your heaviest internal components forward or back...don't move the wing to balance.
As you can see you don't have much leeway to make mistakes...1/4 of an inch either way will make you nose heavy or tail heavy.
The normal range is 25% to 30%.
25% is best to start out with...it will fly straight.
Nudge the CG balance point back for more maneuverability(more 3D)...but don't go beyond 30%.
If you were starting at 2.75" back from the leading edge...there's no way it would fly...
2.75" on a 6" wing cord is 48%...that'll never fly.
A 25% balance from the leading edge of the wing will do wonders.
Remember...conventional wing...25-30% GG from leading edge.
I prefer 25%-27%.
Be as precise in you measurements and balancing to 25% as possible.
Please report back your findings.
PS. If this doesn't fix the problem then we need to look at angle of attack of the wing.
Your angle of attack may be too high.
If your COG is at 25%, but your nose still rises when you apply power...that's a giveaway.
It means the front of your wing is mounted too high. By mounting your wing up on that pod, when you apply power the wind from the motor is hitting mostly the bottom of the wing, causing the nose to rise.
If your angle of attack is too low...the nose will dive on throttle up.
This will take a little designing, but if you are willing to experiment, here's how to proceed.
Keep the height of the back of the pod as it is, but trim the pod in a straight line so when it gets to the front of the pod it meets the fuselage.
In other words. the pod is now a long triangle with the full pod height in the back...and no pod height where it ends in the front.
Mount the wing and balance to 25%.
Try to fly it.
If adding throttle still makes it climb...the wing is still too high in the front.
Add a loose spacer of foam thickness on the wings trailing edge, and try again.
If adding throttle makes it dive...then the leading edge of the wing needs more height...
Add a foam spacer to the leading edge and try again.
At some point you will get to the proper shape of the pod, giving you the proper angle of attack for that specific wing with a CG of 25%.
It should fly and glide straight and true...under power...or with power off.
The CG of 25% is very important...it must be maintained...and the angle of attack of the wing becomes the factor you are changing.
Once you get the pod trimmed to give the wing the proper angle of attack, it should be suitable for most wing styles.
Hope this made some sense.
PPS. Another method is to mount the motor with some washer spacers to pitch it down...but do this only after addressing the angle of attack as well as you can.
PPPS. Maybe rather than cutting the pod down totally to start with...go in 1/4 inch increments.
Measure down 1/4 from the top of the front of the pod.
Draw a straight line back to the top of the back of the pod.
Trim the pod along the line
Balance to 25% COG and try it.
As you lower the angle of attack by 1/4 inch increments you should see gradual improvement...until at some point you may go too far and the nose will dive on throttle.
You've gone past the ideal angle of attack.
Back up to the point the plane flew and glided the best (at 25% COG).
Please report back any findings.
Remember...always set COG at 25-27%...then adjust for proper angle of attack.
If at some point you get rid of the pod and mount the wing closer to the fuse...you can still play with the angle of attack.
