I got parts in the mail this weekend!
I can't seem to upload files at the moment, so I'll post the play by play and add pics when I get the problem figured out.
I had originally planned on building this as a BT-70 airframe but decided to scale down to BT-50 at the last minute due to economies of scale. We have a couple of other projects waiting in the wings that need 24mm tube, so this got the most bang for the buck when we placed the parts order. The boattail also entered into the decision. I had been playing with the idea of scratch building it, just in case, and decided to scale it down to make that process simpler if it came to that.
My first efforts were focused on the boattail. I have never made one before and I learned a lesson or two along the way.
- Start with a shorter nose cone. I had to do quite a bit of shaping after I cut it to length.
- Use plastic if possible. Hollowing a BNC-50Y took a little while.
- When working with balsa, cut the shoulder to length before thinning the walls.
The tail is 1.5" long with a 1/8" shoulder for gluing. I had planned on fitting it with a larger exhaust tube in order to protect it from heat but scaling this down to a 24mm body tube made that a bit of a challenge. In the end, I fitted a BT-20 exhaust and coated the ID of the tube with epoxy. I am relying on cool air from the intake to protect the tube. This will make motor installation quite a challenge but I have a couple of ideas in mind to deal with this.
The MMT is of standard construction and the AFT end is recessed 1" in the BT. The AFT centering ring is 1/4" above the AFT end of the MMT and I am planning on 1/8" of overhang. This will allow for 1/2" cut outs in the body for fresh air intake and allow for a couple of different options for motor retention.
Next on the list is cutting fins and intakes. The intakes will span the fin roots, so my plan is to mark the length for the intake, glue the fins and then cut the tube. I will be using epoxy fillets since the fins will be providing a structural element to the airframe. A layer of glass over the fin can may be in order as well. The only thing keeping the exhaust section on will be the fin and a thin strip of airframe under the fin.
As always, your thoughts on this are appreciated.
I'll add some pictures when I get it sorted out.
Still can't upload images so here is a link to the album.
LINKY