Corraptor - 6th Entry for 2014 Sweepstakes

Started by sanjayrai55, May 08, 2014, 06:46:40 PM

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sanjayrai55

FT have plans for a park sized F22 Raptor. As I only get foamboard (too heavy) and biofoam (too weak) here, I have tried to make this from Corro - ergo, the Corraptor :D

sanjayrai55

Printed the plans on A4 sheets and taped together. Fair bit of arithmetic to adjust the dimensions due to the difference in thicknesses. Also, no tabs for location

sanjayrai55

Used hot glue

sanjayrai55

Motor: 2826-1400 KV. Prop: 9*47 SF. Span: 660 mm. Expected weight without battery: 300-325 gms.

sanjayrai55

Weight with Zippy 1300 mAh is 425 grams.

sanjayrai55


sanjayrai55


sanjayrai55


VC

Aaa haaa! The Sahib is getting colourful.
Growing old is mandatory, growing up is optional!

K K Iyer

GRAND CLEARANCE SALE!
Brand New Models being given away!

(Hope to see such a post from Sanjay Rai sir on 16th May)

K K Iyer

Sir
We want photos of ALL your models in one place.
Please start a new thread under RC People.
Suggested topic name: 'Asli Aeromodeller'

sanjayrai55

Iyer sir...I have already given away quite a few models. Space shortage, plus there were others whose need of the moment was greater than mine :)

sanjayrai55

I could post pics of all the models in one of your posts sir ;) :D

VC

Sahib, I can't get over that book rack in the background. What treasures does it hold?
Growing old is mandatory, growing up is optional!

sanjayrai55

VC, that is one of the book racks, This contains fiction, and a few reference books. Then in the next room, is a larger rack, with religion, philosophy and reference. Then under the stairs is another rack, only fiction. In my bedroom, there are some more on religion. In my younger son's room is the good stuff; comics, graphic novels, Archie, Tinkle, ACK, Star Wars, Lucky Like, full Tintin and Asterix etc. In my elder son's room are mostly management and technical stuff.

The library actually needs a proper place, and cataloging. Also some books need repair/binding. Have to do all this sometime  :headscratch: :headscratch:

Hoping one of my sahibzadas gets married, and I'll bribe my daughter-in-law to do it  ;) :giggle:. Needs a woman's touch  :rofl:

There's also the matter of several hundred DVDs and Music CDs

sanjayrai55

A member asked me how I stick corro. I'm replying here, in the hope it might be of use to others too.

1. Surface Preparation: Scuff up a little with Sandpaper. Then rub with NC thinner with a rag cloth. Corro when manufactured has a thin layer of Silicon Oil (mould release compound) on it

2.Adhesive - (a) Pidilite's SR 998 works very well. Apply a thin layer on each side, and let dry till it is tacky, nearly dry. Press the two sides together, and hammer lightly with your hand. Advantage here is you don't have to clamp. Especially useful for the long seam in the wings. The joint is also openable, with a very hard pull, but never has opened yet in service (with me)
                  (b) Cyano: Use thin Cyano. I find a product by Pidilite (again, and no, my uncle does not own the co.!) called Flex Bond works well. Put dots of glue about 1/2" apart; the low viscosity and wicking action ensures it spreads. Bonding is super-fast, and permanent. If you have to open the joint, it's likely the corro will tear.

For corro to wood, both work well.

sanjayrai55

Hot glue makes an excellent joint between Corro-Corro and on Depron too (if you are using a composite material build)

Clean as usual, then apply on one surface. The glue should be really hot : use a higher wattage gun. I use a 40 W Stanley, works good. It can (and should) melt the corro very very slightly, thus ensuring a weld-like bond. Flipside is it's heavy  >:(

But there are some places it's indispensable really. eg, bonding a turtledeck to the fuse sides. Conventional glues will have a poor bond because this is a butt joint, with one member having the flute edge being glued, presenting very little surface area.

I generally use a combination of all these methods depending on the location of the joint to be bonded

sanjayrai55

Another gentleman has asked me:

"Was wondering if you can help me with the source of coro in Delhi/NCR ?
I did get thin yellow 2mm sheets but they arent usable. I guess we need 3-4 mm with some more density ( GSM ) to it."

Any sign board maker can assist you with Corro supplies. But the wholesale market is in Paharganj, with m/s Pearl Plastics being one of the well known retailers.

When selecting Corro sheet (fat chance you will have this choice though, it's a take-it-or-leave-it attitude there) the sheet should be crisp and shiny, not spongy, nor brittle. Thickness is not all, there are at least two types of flute spacing, one close-spaced and one more distance-spaced. Obviously the close spaced one is heavier, but stronger.

Why do you feel 2 mm are not usable? Which model are you building? 2 mm is pretty good on wings up to 54" (my experience) and for fuselages with doubling on strategic stressed locations. Control Surfaces like Rudder, Elevator Aileron by their very nature need to be rigid; use 4 mm normal spaced or 3.5 mm close-fluted for this.

Good luck, and let us know your progress :D

girishsarwal

gs

maahinberi

Maahin Beri - Introduction and Hangar
Seagull Arising Star, Seagull Low Wing 40, AviSport (SPAD), Phoenix Scanner, VortexRC Speedster, Martian 220 Racing Quadcopter.

topalle

Now sir, please make a composite BAE Hawk (coro + thermocol) .... Mine will follow have been waiting to see someone build that...let it be your first edf... ( good news... electronics budget sanctioned... bad news... i wont make it in this sweepstakes...)
Amateur photographer ... DIY enthusiast ... Scratch Builder... Student-Innovator

sanjayrai55

Thanks Girish. Maahin, I hope you don't have your eyes on this too  :rofl:

sanjayrai55

Thanks Topalle. No more jet-type models for me for some time now ;)

topalle

I was not asking for a a jet-type but  a real jet. Ok, perhaps someone else will make it.
I haven't seen a single scratchbuilt EDF Hawk here...
Amateur photographer ... DIY enthusiast ... Scratch Builder... Student-Innovator

sanjayrai55

I'm not really into jets, speed, that stuff