grrmisfit

first wood arf that ive taken on and so far its been fun but im curious on the tail skid .. they say to just press it in but it doesnt go in that easy .. should i just drill a small hole and put it in that way? i realise its not a critical building point but i want to do it right

MinnFlyer

My Feedback: (4)

If it's too tight, you can open the hole with a drill if you want. just don't go too deep!

grrmisfit

ty got that done..

now ive read that a lot of people will spread a thing layer of epoxy over the firewall to fuel proof it.. do i just use 6 min epoxy for this?

hrrcflyer

Yes, that will be fine.

ChuckW

Most GP ARF's have a sealed firewall from the factory. If it looks a little shiny then you are good. If you want to be sure then you can get brush on epoxy or just use the 30 minute stuff thinned with a little acetone or denatured alcahol. You want it to be brushable and have enough working time so it goes on smooth.

opjose

6 minute epoxy will not give you enough working time.

You want 30 minute epoxy.

Mix up the epoxy FIRST, then once the mix is smooth, add a bit of alcohol or acetone.

I prefer alcohol since it will not attack covering or paint.

Mix everything until you are left with a runny syrupy mixture.

Use a brush to cover all exposed firewall wood, and anything that is left over use on exposed inner surfaces, particularly wood joints, to add a bit of strength.

As ChuckW mentioned the Stik already has fuel proofing, but a bit more will not hurt.

grrmisfit

i noticed when installing fuel tank theres no foam padding nor room for some.. is this normal? my first nitro model i was told to wrap tank in foam before installing to prevent foaming.

dignlivn

At least put some foam on the and the top of the tank.
I use old beer coozies for foam. You have to force if you
try to put on the sides with a ruler.

JMO I don't use the tanks that come with arfs.
Bob

opjose

It is better to provide some shock protection so that the fuel does not foam up.

Almost anything that provides some degree of isolation helps.

In lieu of that I resort to the bubble-less clunks.

I did this with my Big Stik 60 and never had any problems.

grrmisfit

now on to my next small question it seems there is no hole for the throttle tube  right before the servos like there is for the rudder/wheel . should i drill one? when i move the arm with servo it raises up a bit

heres a picture http://img18.imageshack.us/img18/6647/imag0515h.jpg

opjose

Yes, many planes do not come with a tube hole pre-drilled so that you can utilize different types of engines and setups.

Remember to avoid using an all metal pushrod setup from the engine to the servo as this can cause interference even with 2.4gHz.

I try to use plastic Sullivan Gold-N-Rod setups for the throttles when possible.

cutaway

Dollar Tree has packages of foam sheat in different colors. One is about 1/8" think, annother is about 1/16".

flyhigh2

   I have a big stick 40 and have been having trouble with the pin in the front of the wing breaking and allowing the wing to be pulled off. has anyone used bolts in the front of the wing like the back?

grrmisfit

never seen that done but what i have seen done is wooden dowels put in on each side on the front then rubber banding it down. tho i must say ive never seen it done on the big stik but quite a few top wing models

cutaway

This is a common failure mode.

I believe what happens is ultimately due to the nylon bolt mounts at the TE's. The plywood lugs the blind nut come up through are recessed well below the bottom of the TE which allows for the wing to slide to the rear a bit in flight.

When the wing slides back (its only bearing against about 1/8" balsa sheet on the top of the fuselage, which may be pretty soft), even a little, two bad things happen. The bolts now have a bending load placed on them in addition to tension, and flight loads start to pry on the dowels in the front with MUCH greater force than if they were a snug flush tight fit in the plywood former's holes. The lite-ply former with the holes is also marginal IMO. Those holes in the soft ply eventually get a bit whupped out and become sloppy.

The nylon bolt blind nut issue can be mitigated by gluing spacers with a hole in them to the top of the lug block. The holes in the ply former and the dowels can be hardened up with some CA to slow down their deterioration.