$50.00 Scratch Build Contest Entry, F-20 Tigershark
#1

Hi Everyone
I always Wanted a F-20 TigerShark
So, I think That this will be my $50.00 Scratch Build Entry, I will be making it out of depron and Balsa, It will be a pusher prop, I think a 36 to 40 inch wing span will be nice and easy to see for these old Eyes
Ok, Now I have to Clean up my Hobby Room to make some room for this build
Hopefully it will look something like these Pictures, Wish me luck, Chellie










Last edited by CHELLIE; 09-09-2013 at 12:16 AM.
#2

I Finally Got a Chance to get to my Build
I am Drawing up my Plans, I will be using the drawing above as a Base, the wing tips will be wider at the tips for RC use, the bottom will be flat for a lifting body affect, the top of the wing will have a air foil to improve lift and hide the retracts if I decide to use them, I have to build this thing and see how it goes
The intake ducts wont be so wide as to lessen drag, the rear stabilizer will be a little wider at the ends for rc use, I am starting to get ready to put it together, just a few more Measurements
It looks like it will have about a 34" W/S and be about 60" long, It should be big Enough so I Can see it way out there
Take care and have fun, Chellie




#3

Very nice - just about the size of my Fairey Delta 2.
Not quite sure of the "wider tips for RC use..." though. True scale is half the fun!
Now if I crash and destroy one of my existing EDFs I would have space to build something......
Not quite sure of the "wider tips for RC use..." though. True scale is half the fun!
Now if I crash and destroy one of my existing EDFs I would have space to build something......

#4

I got most of the measurements done and I am off to cutting foam
I am Starting at The tail feathers with this build and working forwards, I wanted to get the hard stuff out of the way first
I am Using a Lot of my scrap 9mm Foam for the bottom part of the Jet, I tape a hinge with packing tape on one side of the foam, epoxy the seam, then wipe any execs epoxy off and put some packing tape on top, that makes for a very clean joint, the 9mm foam will be the wings, stabilizer, rudder assy. and bottom of the fuselage, the sides of the fuselage will be balsa, 6 and 2 mm Depron, here are a few pics, Take care, Chellie


#6



#7

I got 2 more pieces of foam cut out and Epoxied in Place, Its starting to look like some thing Now
I used the same Packing tape hinge and epoxy method to glue up these scrap pieces of 9mm foam, the epoxy joints are stronger than the foam itself
now I need to box in the fuselage and cut out the control surfaces, Take care, Chellie




Last edited by CHELLIE; 09-10-2013 at 09:23 AM.
#9



#10

Its getting there little by little
I cut out the elevators and ailerons and Hinged them with packing tape, I leave a 1/16" gap between the control Surfaces, so the surface will bend down and not cause the tape to stretch and bind, i use a small piece of scotch tape to hold the gap, before I use the wider packing tape to hinge the surfaces, I use 2 layers of tape on the top and one on the bottom, that seems to make the hinge very strong with out making the hinge to stiff, here are some pics, Enjoy, Chellie





Last edited by CHELLIE; 09-11-2013 at 08:20 PM.
#11

Ok, Now I am going to work from the front towards the rear, I think the tapered nose will be a bit of a Beach to do
I want to use balsa to make the Fuselage Stiff, or I wil have to Epoxy some wood Yard sticks in the fuselage to add Strength, I will try to soak the balsa in some ammonia and water to soften it up to shape it, Wish me luck as I have never tried to use ammonia and water to soften up balsa before
Here goes nothing 



Last edited by CHELLIE; 09-11-2013 at 08:36 PM.
#12

Ok, now what in the heck Did I get Myself into
Trying to form the turtle deck & Fuselage is being a real PITA
I had to score the heck out of the 6mm depron on the back side, use Packing tape to pull the foam together while heating it, and I only have 2 hands
I Think I got it though
What a pain
here are some pics of me Struggling with the foam to get it formed, Enjoy, Chellie








Last edited by CHELLIE; 09-12-2013 at 10:36 AM.
#13

I Rounded out the rear top part of the fuselage and placed it on the bottom part of the jet and it fits
Ok, I will admit it, trying to shape that Foam to fit, Beat me up a little, Thats enough for today
I need to get my beauty Sleep
Take care, Chellie





Last edited by CHELLIE; 09-12-2013 at 10:45 AM.
#15

Thank You
I was going to start on the nose first, but I needed a reference for the nose part of the fuselage, so I had to start at the back part to get it, I did not have enough balsa for the rear part of the fuselage, so I went with foam,Take care and have fun, Chellie

#16

Chellie
That's quite a bit of Depron bending! It looks very nice
I have laminated 2 or more layers of thin 2mm Depron to get a sharp curve using PVA as the glue. It has to held firmly in place and takes 24 hrs to dry but the end result is almost like moulded 3 ply.
However my preferred method is 'planking' over formers mainly because individually fixing each plank puts very little load on the structure.
That's quite a bit of Depron bending! It looks very nice
I have laminated 2 or more layers of thin 2mm Depron to get a sharp curve using PVA as the glue. It has to held firmly in place and takes 24 hrs to dry but the end result is almost like moulded 3 ply.
However my preferred method is 'planking' over formers mainly because individually fixing each plank puts very little load on the structure.
#17

Chellie
That's quite a bit of Depron bending! It looks very nice
I have laminated 2 or more layers of thin 2mm Depron to get a sharp curve using PVA as the glue. It has to held firmly in place and takes 24 hrs to dry but the end result is almost like moulded 3 ply.
However my preferred method is 'planking' over formers mainly because individually fixing each plank puts very little load on the structure.
That's quite a bit of Depron bending! It looks very nice
I have laminated 2 or more layers of thin 2mm Depron to get a sharp curve using PVA as the glue. It has to held firmly in place and takes 24 hrs to dry but the end result is almost like moulded 3 ply.
However my preferred method is 'planking' over formers mainly because individually fixing each plank puts very little load on the structure.


#21

Thank you 
Thank you
Dollar tree foam is what I might have to use on the nose, because like you said, its easier to shape, I am just trying to use up what I have laying around here, Take care and have fun Guys, Chellie


#22
Super Contributor
Join Date: Mar 2011
Location: Fond du Lac, WI
Posts: 1,030

Even if the can is a little over-sized, it puts a nice curve in the foam that can be used to make a cylinder that's the correct size. Very useful for foam cowls, turtle decks, and EDF thrust tubes.
#24

If you can find a can the right size, cover the outside of your foam with packing tape, tape it to the can and fill the can with boiling water. That happens to be the perfect temperature to mold foam. You may have to add the boiling water twice for thick foam.
Even if the can is a little over-sized, it puts a nice curve in the foam that can be used to make a cylinder that's the correct size. Very useful for foam cowls, turtle decks, and EDF thrust tubes.
Even if the can is a little over-sized, it puts a nice curve in the foam that can be used to make a cylinder that's the correct size. Very useful for foam cowls, turtle decks, and EDF thrust tubes.



#25

I was trying to figure out how to make the nose and front fuselage assy. I was going through my RC junk pile and found a Stryker foam Nose
Hmmmmm that looks about right, Yea, That will work
so I trimmed off the 2 plugs on the back side, and cut out a 9mm piece of foam for a form to glue foam onto, soo that piece of foam got epoxied to the rear of the nose piece, now that will give me something to work with
, I had to hold the nose down a little with some weight to get the right angle before the epoxy hardened. Its getting there, I got a little side tracked with my EBay Sales and overhauling a McCoy 35 Red head for a customer, the McCoy Engine came out real nice, so that was a little extra money for my RC Hobby
and I have another McCoy 29 coming in to be overhaul for a customer, Thank Goodness they are in no Hurry for that engine
being retired, the extra money sure helps
Take care and have fun, Chellie








