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Oct 17, 2019, 06:45 PM
new to the sport
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Build Log

Ridge Rat - old school design, new school tweak


Hi Phil here from Wellington, New Zealand.

I was inspired by a fellow scratch builder over at the flitetest forum to build a Ridge Rat

I am new to sloping but these ships are cool and I wanted to get in on the action. The aerofoil is updated to an MH32, and the nose is longer, but otherwise, it kinda follows the original version. I am also using a braided CF sleeve for the fuse and am 3D printing the wing!

this will be a bit of a catch up to where I am at currently!

the design
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Oct 17, 2019, 06:49 PM
new to the sport
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the fuse has a green foam inner with a braided CG skin. I inserted a push rod sleeve up the centre for the horizontal stabiliser (no rudder. bank and yank), and then epoxied the sleeve wrapping it with cling film - worked way better than expected!
Oct 17, 2019, 06:51 PM
new to the sport
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The wing halves have 1 deg dihedral, and the design is based on PLA and is 3D printed with two 3mm x1mm carbon flats to help with rigidity.
Oct 17, 2019, 07:12 PM
new to the sport
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Next came the tail feathers and I opted for 2mm balsa with carbon tow and FG skin. I am all new to this so it was trial and error, but they came out amazingly stiff compared to the balsa on it's own.
Oct 17, 2019, 07:16 PM
new to the sport
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I have this little technique for making hinges with micro cable ties. I 'V' them in the middle with a cold chisel and glue them into the wing or stabilisers - the cable ties work well and bend forever!
Oct 17, 2019, 07:18 PM
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chip.greely's Avatar
As I recall, the original Ridgie had a fat fuselage to accommodate the period correct servos. Bashers used to thin the fuselage, once smaller servos came to be.

Was going to suggest you do the same,...but looks like you are pretty far into it already
Oct 17, 2019, 07:22 PM
new to the sport
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As mentioned before the wing is PLA and 3D printed with 3mm x1mm CF flats as stiffeners. The parts are all modular to fit in the machine with the LE and TE caps being the tricky pieces as they butt together. In part, the CF flats are there to tie everything together!
Oct 17, 2019, 07:25 PM
new to the sport
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To fit the wings to the fuse I have opted for some 6mm FG rods that are glued into the fuse to receive the wings which have 7.3mm CF arrows used as mounting tubes. Luckily the internal dia of the CF tubes is 6.0mm!
Oct 17, 2019, 07:31 PM
new to the sport
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we are catching up now to where I am at with the build! To complete the wing structure I needed some mounts for the aileron servos which in the end worked out well nesting between the CF flats.

I also did some testing with Monocoat over the PLA (another first) and, well, to be honest, it was a bit of a disaster. The shrinking temp (and my skills) just warped the PLA all over the place. I investigated some options and for good or for bad I used clear book covering material which has a room temp adhesive and required next to no heat to tighten it a bit!
Oct 17, 2019, 07:33 PM
new to the sport
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My next chore is to fill and sand the fuse and fit the tail feathers
Oct 17, 2019, 10:27 PM
F3Foamie Pilot
Very impressive work !

Nice to see new techniques applied.
Oct 17, 2019, 11:02 PM
Registered User
Ward Hagaman's Avatar
Very nice!

Carbon or even glass over foam makes a super stiff fuse, especially if you can leave most of the foam in.

Impressive printing...I’ve only done root ribs for a twisty so far. It will be interesting to see how it holds up.

Keep us posted! Love the innovation!
Oct 18, 2019, 12:37 AM
new to the sport
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Quote:
Originally Posted by Ward Hagaman
Very nice!

Carbon or even glass over foam makes a super stiff fuse, especially if you can leave most of the foam in.

Impressive printing...Iíve only done root ribs for a twisty so far. It will be interesting to see how it holds up.

Keep us posted! Love the innovation!
It might hold up if it stays in the air! Yes glass over foam is good too. I have done that on another ship that is yet to fly! The benefit of this 3D printed wing is possibly convenience without a mess!
Oct 18, 2019, 12:39 AM
new to the sport
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Quote:
Originally Posted by Slopemaster
Very impressive work !

Nice to see new techniques applied.
Thanks for the kind words - I am as keen as you are to know if it is a success or all in vein!
Oct 18, 2019, 03:28 AM
new to the sport
Thread OP
Quote:
Originally Posted by chip.greely
As I recall, the original Ridge had a fat fuselage to accommodate the period servos. Bashers used to thin the fuselage, once smaller servos came to be.

Was going to suggest you do the same,...but looks like you are pretty far into it already
Hi Chip,

I looking at the original RR plan, yes my fuse is a little slimmer. Also, the original wing was 9" and my MH32 is 6" which makes the nose of my ship longer from the LE and leaves the TE to horizontal stabiliser roughly the same - let's hope it will work!


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