RC Groups

RC Groups
    Scale Kit/Scratch Built
        Build Log Scratchbuild (STOL) Carbon Cub SS - built with carbon fibre tubes

#1 Phaeton May 08, 2011 09:09 AM

Scratchbuild (STOL) Carbon Cub SS - built with carbon fibre tubes
 
2 Attachment(s)
After scratchbuilding a balsa Super Cub, it's time for the next one. A Carbon Cub SS. Also based on Ed Westwood plans which are slightly modified for the occasion.

Characteristics, general:
  • As light as possible.
  • Wingspan about 110 cm, some 43".
  • Length about 75 cm.
  • Weight should remain below 450 gram.
  • Same paint scheme as the example.
  • Cowl will be a challenge...

Characteristics, fuse:
  • As light as possible.
  • The fuse will be build with 2mm (1/32") hollow carbon tubes.
  • Straight joints are to be reinforced with 1mm carbon.
  • Bent joints are to be reinforced with 1mm pianowire.
  • Hollow square carbon (also 2mm) will be used for window- and doorframes.
  • Full functional door on starboard to get the lipo's in and out.
  • Double 1mm Single 1.2mm ply for the base plate relative to which everything will be placed.
  • Double 1mm Single 1.2mm ply for the wing roots.
  • Double 1mm Single 1.2mm ply for the firewall.
  • Very thin veneer strips around 2mm carbon for the horzontal and vertical stabs, which will be 2mm thinů
  • Full functional landing gear, the same construction as in the previous build Super Cub.

Characteristics, wings:
  • As light as possible.
  • Flaps anyway.
  • Two wing halves instead of one full wing.
  • Don't know the rest yet ;)

Setup:
  • That totally depends on the final overall weight, but probably a Hacker A20-50S, spinning an APC-E 8x4, draining from a ThunderPower 3s1p 1350 mAh lipo.

To be continued...

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#2 bob_suruncle May 12, 2011 10:58 AM

I'm watching.... did you ever maiden the red one? just wondering how she flew.

#3 Phaeton May 12, 2011 11:51 AM

1 Attachment(s)
Quote:

Originally Posted by bob_suruncle (Post 18215854)
I'm watching.... did you ever maiden the red one? just wondering how she flew.

Maiden of the red one was planned this evening, but wind doesn't permit. Now scheduled for tomorrow... I'll post the results. Or bits & pieces :D

Building of this one starts this weekend:
  • Make myself some kind of mold to make sure (this time) everything that should be square will be square.
  • Start with the rear end of the fuselage, that's what I have carbon for.
  • Square carbon tubes for the cabin are in the mail, will be done later.


http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#4 Phaeton May 13, 2011 07:47 AM

Ingredients
 
3 Attachment(s)
Ready to go (fuselage)... :)

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#5 Phaeton May 14, 2011 09:37 AM

First tryout
 
8 Attachment(s)
A little work done to see how those little tubes handle.

The base plate (ply with two corresponding cf tubes) was done quickly. Glued the "V" together, bent two pieces of pianowire and put things together.
  • The joint is very solid.
  • Margins are very small, a little deflection up front is a major (off center) deflection at the back.
  • This requires a very precise mold, have to think about that one now, it will make a huge difference. And makes things a lot easier.

(Oh, and we didn't maiden the red SC yesterday, will be somewhere next week now)

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#6 Phaeton May 14, 2011 02:00 PM

Couldn't resist
 
8 Attachment(s)
Vertical stabilo:

- 2mm cf tube as outline
- 1mm cf tube in between
- pianowire in the joints

And it is very (very) rigid, perfectly flat, perfect fit and very light. And to be honest, so far it is more fun to work with than balsa...

The challenge was to get the Dubro hinge through. I tried to dremel a slot first, but that didn't work. Next was a razor blade, cf is fibres after all. That worked. Two cuts and the hinges were in.

This whole "structure" is below one gram. Promising...

That's it for now. Mold first.

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#7 pburress May 14, 2011 02:44 PM

Very interesting! Are you using CA glue? And are you wearing a mask to protect from CF dust?

#8 Phaeton May 14, 2011 02:50 PM

1 Attachment(s)
Quote:

Originally Posted by pburress (Post 18234539)
Very interesting! Are you using CA glue? And are you wearing a mask to protect from CF dust?

I'm using regular superglue. And there's hardly any dust with this tiny stuff. Cutting is done above the sink on the downwards spinning part of the Dremel disk.

Even worse, I did this wearing white pants and a white T-shirt. And everything is still white ;)

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

#9 pburress May 14, 2011 03:20 PM

I was thinking the flexible-type CA would be a good choice for this... Less brittle.

#10 Phaeton May 14, 2011 04:15 PM

Quote:

Originally Posted by pburress (Post 18234782)
I was thinking the flexible-type CA would be a good choice for this... Less brittle.

Could be. I only have experience with epoxy, this superglue and UHU Por. But everything that works, works.

Yvo

#11 Phaeton May 17, 2011 05:39 AM

Rudder
 
8 Attachment(s)
Quicky during lunchtime... ;) Took me half an hour.
  • Two layers of 2mm wide and 0.13mm thin carbon strip
  • A 2mm cf tube
  • And 1mm cf rods in between

The first strip got 1mm holes in it to get the 1mm cf rod through (very delicate process, the strips may not break). The second strip is added for strength. We call it laminating, Dijko's technique.

And this whole thing is 2 gram...

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#12 gklein May 17, 2011 03:16 PM

Nice project. I am following it with great interest..

#13 Phaeton May 21, 2011 09:28 AM

Molding
 
11 Attachment(s)
Made a perfectly square mold this afternoon, tail boom is ready, glue is hardening, next is the cabin.

Builds fast like this... :D Cut carbon & joints, slide the pieces together and that's all.
Admitted that I've prepared the balsa/ply in advance...

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#14 Phaeton May 21, 2011 11:20 AM

1 Attachment(s)
Getting a bit nearer... Needs trimming and adjusting, but you'll get the picture now.

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.

#15 Phaeton May 21, 2011 02:04 PM

This is fun
 
9 Attachment(s)
Builds very quick. See below.

And only 36 gram total now (1.27 oz) !! :D:D

That's all for now, have a great weekend,

http://static.rcgroups.net/forums/at...g?d=1254167788

Yvo

.


All times are GMT -5. The time now is 01:17 PM.