Easy Fly ST330 RTF

I seem to have spent the whole day just cutting, fitting and glueing foam yet there is still an awful lot left to do.

At least I have achieved a 'first fit' of the bits.

The fin and tailplane are now glued on. The elevator servo is installed and tested.

As the nose is by far the most damaged, I have delayed even thinking about how to repair it but as only the motor, battery and ESC have to go in (no servos) it should be possible to fill in most of the moulded in cut outs which will add some rigidity.

It looks like the airframe and servos will weigh 20oz which should mean about 30oz with a 180W motor & 2200mAh 3s.
It won't have a sky rocket climb but then the airframe is nearly twice the weight of my comparable Depron job.

Its come a long way you obviously like a challenge.

Still grinding on.
The carbon spar is covered by a big foam insert, unfortunately it stands proud by a couple of millimetres. The same both sides so it appears to be a 'feature' rather than an error.
Nevertheless such a step on the underside spanning nearly 2/3 of the wing can hardly improve the performance so it has been carefully shaved down flush. Before and after.

It had to be 'shaved' as the EPO(?) foam is rather rubbery and does not sand at all well.

Now the cockpit area.
The rather tatty inside.

The underside showing the two repairs.

The cockpit is rather crushed on the left side.

It has left a slight 'banana' to the fuselage.
This damage and the more extensive abrasion on the left tip suggests it probably tends to drop its left wing first!

Ive seen someone demonstrate that holding the damaged area in the steam from a kettle heats the trapped air and returns the foam to its original shape,is this something youve done yourself Quarneng? Im enjoying the attention to detail you are showing us and also the way your reducing the weight.

I have used heat on foam to restore shape but in this case I fear the crushing is severe and very localised such that the individual cell walls are cracked. As a result in that area the foam has lost a considerable part of its strength and stiffness. A similar problem to the motor mounting of your Super Cub?

My solution is
1. Fill in all the servo cut outs
2. Add a new cockpit floor
3. Thicken the cockpit side walls
4. Raise the height of cockpit sill
It will all be done in Depron so will only add about 3/4oz but will more than double the amount of foam at the weakest area of the cockpit.
After another full day cutting and glueing bits of foam the cockpit rebuild in progress.


The patched up wing/fuselage mounting.

Note the original substantial cooling air vents on either side that were completely glassed over!

The final profile of the fuselage nose will have to wait until the motor is delivered.

I see what you mean referring to the cub,and do you use cyano to glue the depron.

Where I am gluing large flat areas, like joining two blocks of foam together, I use UHU POR. As it is a 'contact' adhesive after a couple of minutes the surfaces are pushed together and stick - permanently!

For everything else I use PVA wood glue. Takes 24 hours to dry but it is relatively cheap. It is a 'filler' type glue so the joint faces do not have to be so accurately cut yet it still achieves a strong bond.

Thanks for that information.Ive used UHU POR get on OK with it.Ive also used the wood glue as well,but mainly superglue with good ventilation.Have you used gorilla glue ,never tried it but understand it expands.

The cockpit area rebuild is more or less complete.

All the old cut outs are filled with Depron, the floor levelled off and the cockpit walls thickened by 6mm.
The extra wall thickness is also brought up to a new sill line.

The cockpit area is now quite as rigid as the rest of the fuselage.
I am still thinking about the actual canopy.
There will be some additional foam reinforcing in the extreme nose but this will have to wait until the motor mount is installed.

The airframe (with servos) weighs 20oz leaving 10oz for motor, battery, ESC and radio to achieve the target 30oz all up.

Superbly done really looks a very neat job,very impressive work.

Can almost see the end of this but not quite there yet.
The wing halves pushed together. They will be held together by a pair of rare earth magnets unlike the original which required two screws to hold the wings.

The enlarged centre section fits the fuselage cut out, keeps the wings in line and prevents them from twisting round the tube wing joiner.
The leading and trailing edge cut outs locate on matching lugs moulded into the fuselage.

Quite a neat arrangement and apart from the aileron servo connections it should be a simple "push together" assembly - I hope!
Finally I will have to be very careful pulling g manoeuvres. The wing is nothing like as strong as my 2m Depron one. The aluminium wing joiner is the weak point and it can just about carry half the centre load (9oz) when supported by its tips although the wings themselves could probably carry more.
I will try to find a suitable CF tube to replace the aluminium joiner.

Hopefully Giant Shark will deliver the motor tomorrow. I already have a suitable folding prop and spinner.

On the Multiplex easy star they used a similar idea to join the wings together sort of just clipped together.Hasnt taken you long to refurb this model,hope its successful for all the work youve put in.

The GWS radio (35mHz) installed out of harms way up behind the cockpit.

The aerial will be taped along the top of the fuselage and up the leading edge of the fin.
This installation keeps the radio and its aerial about as far away from everything else as possible.

The elevator servo buried at the base of the fin with a simple direct link to the horn.

The control surfaces are hinged with white duct tape.

Hi Simon, sorry -you know me and questions lol but why have you had to put the GWS radio "out of harms way"? And whats with the aerial?? I haven't got to fitting the inside of mine out so not researched the mechanical stuff as much yet but haven't seen anything saying I need an aerial so is that just reserved for flying using 35 Megahertz as opposed to my 2.4 Ghz??

It is a good idea to keep the radio and its aerial as far away from anything that might create electrical interference.

Motors and ESCs are the most likely as they operate at high electrical frequencies.

The reception to the radio can be blocked or distorted by metal objects or wires running close to its aerial.

Unlike 2.4, a 35mHz Rx has a long aerial (up to 100cm!) so you have to consider where to run it on a model that keeps it away from anything metal.
The crystal in a 35mHz Rx only responds to a very exact frequency but if anything else matches that frequency it cannot tell if it coming from the Tx or not so it will react - in some way or other!

In general 2.4 suffers much less from interference simply because the Rx is clever enough to completely ignore any radio signal that is not in exactly the right form as the Tx that was bonded to it. The down side is that 2.4 is a bit more 'directional' so it is important the Tx antenna is not pointing directly at the model.

Hope this helps.
Keep asking questions!