Originally Posted by mmattock

Since you are using the carbon for strength could you get away with 1/32" balsa for the bottom skin as well? Or has that been tried with some nasty results?


Mark

YES, I can and do use the 1/32 bottom on lighter versions like this one with no glass, no carbon edge, and single spar..
6.4 oz with a 450mah 3s, needing only 9 amps static to go 100mph with a DYS 2100kv motor.
Runs, 3,4,5,6s packs.
7.4 oz witb 370 mah 6s.
No issues.
If it was heavier, it might snap...

Cut a small overlap to fit over/around the core and tape down.
I use gorilla clear.
I USED ABOUT 16ML OF A 20ML BATCH..
Special attention is used to make sure all resin is spread even and in an amount to "attract" the skin, with extra resin at the trailing edge and spar area.
The leading edge will get special treatment later..
Take time to forcefully press and smooth the skin down, then apply weight..
I actually wait until the resin starts to set, smooth down one more time, then add weight.
This looks unprofessional but I can assure you, it will come out nice.
As long as the skin is weighted even andnot lifting anywhere, its good
The leading edge will not be perfect but we will adress this later when resin sets...

Once the resin dries, you will notice the skins pull away from the leading edge.
(After trimming skins)
Just take medium and/or thin foam safe c/a and tack skins down, one section at a time, creating an even edge.
Sand the leading edge carefully to accept the 1/8"×3/16 strip.
No worries if it seems uneven, as you will be sanding it all down to a common center.
I used a single 36" piece and curved it using water and heat gun.
A thick bead of medium ca, working in sections, one half at a time.
It helps to press it down on the board with waxpaper to contain excess.
The rest of the l.e. is small scrap pieces.

Here is where it all comes together..
The leading edge is pretty easy to figure out.
Take time, do not over sand.
The trailing edge gets a steady sweep from the current 3mm down to the .5mm carbon.
Pic is after a few minutes sanding, with leading edge formed, but not complete..

Looking good ! How sensitive is this plane to a perfect airfoil ? Some of mine come out really well but others ... not so much.
Nick

Originally Posted by NickDe

Looking good ! How sensitive is this plane to a perfect airfoil ? Some of mine come out really well but others ... not so much.
Nick

Comes out better than expected with the carbon trailing edge, as it gives a very true center point to work on.
The rest.. comes down to matching sides, even from right to left, etc..
How good are one's eyes for this?
Having done many of these gives me that "eye", i guess.
I know I got it right by the way it flies... and NO NOTICABLE TRIM NEEDED!
CANT SAY THAT FOR COMPOSITE KITS ALL THE TIME...

This bigger twin is new territory for me...

I sourced the best, hard 4" and 6", 1/8" balsa for this.
Just draw half, then repeat for horizontal.
This one is 10"
The vertical stab will dip below the fuse-line.
Lets cut and sand these..
Next is a fuselage built around a mock battery..
(Battery is in route..)

Having to build around a mock battery.
The main concern is making sure the wing saddle and horizontal stab are on the same centerline.
I am hoping that there is enough room to slide the battery for CG..

Twice now, a very hard and fast spin initiated a control lock..no rx or esc power.
All gear but esc works good after crash.. the esc had no cooling and burned at the crash site.
I am taking multiple steps to insure no loss of rx or power, including amplified antenna.
The bec seems to work good, but I will add a new one.
It is good for 2.5a continuous, up to 8s, so I am good.
Perhaps a "dynamo" of carbon strips causes brownout??
HERE IS THE DYNAMO...
Accellerate to near full speed an initiate maximum down elevator and
Full up flaperon, while chopping the throttle at same time (Left only, up aileron)
I fly a high rate that is near maximum available throw..
The spin is blindingly fast, scrubbing off 150 mph or more in a wooshing, blurry ball, followed by a couple slower spins to an easily controlled exit.
Done dozens of times.
Sad to see it fall to ground, now twice.
Good news is only the fuse and $17 esc will need to be replaced.
Tail, servo, linkage, and motor WITH firewall can move to the new fuse.
Wing is perfect, battery not buckled. (Difference between falling and being propelled into ground)
Figure less than 5hrs work to have a replacement..

Sorry to see that . I'm sure you will have if flying again soon. 150 mph spins sound scary crazy fun. I've had a few planes that simply could not recover out of a spin at the altitude I was at no matter what control inputs I did. Lost a P-51 Mustang that had small ailerons in a spin and couldn't recover before the plane took a dirt nap.
Nick

I like to hinge everything loose, then sand to match perfectly, then remove for glass.
Rough sand fuse here, about to glass wing and stab..

Spectrum?..

Originally Posted by pnc

Spectrum?..

Yes, I fly Spektrum, with no problems on the full range rx.
I also fly Futaba on the target drones for Gnatusa.
I am using Spektrum for the RX options, and bnf options.
I may have reached a carbon threshhold with the last RX??
New gear to test now..
Getting ready to install gear...

Mock-up here reveals very tight spaces for esc and servos.
The challenge is streamlining the nacell.
At this point, the tail and elevator gear is intalled, and balance is confirmed.
Untill now, it has been a guess.
Now I can see it will all work great, with room for various battery configurations.
7s will be allowed by series plug and 3-4s batteries inline.
IT WILL WORK!
How exciting!!

How do you make sure the motors are putting out the same rpm at various throttle settings ? I guess the same 2 motors and ESCs should be very close in power and rpm all things being equal. If one motor is turning more rpm will it torque the plane into turning ? I'm really glad it's working out and can't wait to see the video of it flying. Looks fast just sitting there !
Nick