Cessna 170 build

[mr.charlse]

Hello.
Since this is my first thread on this forum i thought i would make a small introduction.
I am 13 years old and live in Sweden. I have been on this forum, checking out several builds and other building tips for quite some time now, and have now decided to join the fun .my model-making experience is limited but i think that i am still an average builder. most of my builds before this one have usually not gone so well, but using the tips i have received from everyone at this forum i hope that this one will fly.
Now, on to the build.
i intend to build my Cessna 170 for rubber power, and have replaced all parts with my own parts made from contest grade balsa, from Graupner and hobbyträ (hobby wood). i am using a light-weight plastic prop and will glue everything together with white-glue. i have also decided to make some parts that where previously divided into one, and i have made rudder/elevator in only 1.5 mm balsa

I will post pictures of my progress as it gets along.
-Mr.charlse

[mr.charlse]

You got me.
I am from Sweden.

[mr.charlse]

Im almost finished with the wing. I have done some sanding, but the final polishing will be done before the covering.

[mr.charlse]

By the way,
Since my fin and tail-plane are made of all balsa ( very wobbly ) should i reinforce it somehow?

[Phugoid]

Why Aren't you using the "built up" parts as supplied (or at least lighter copies of them)?

A solid tail will be more flimsy for the same overall weight especially along its length as you are not taking advantage of the grain direction. if you look at the tail on my build closely the grain is hardly ever parallel to the span and when it is it is a very narrow part. This due to the (correct)way the parts are laid out on the sheet.

To strengthen an all balsa surface you can cover it both sides with tissue, be carefull though, it's an easy way to warp the wood if you are not carefull.

On my build I will sand both the tail and fin thinner than the original balsa to save some weight too, remember that every gramme extra on the tail sufaces is probably worth two to three grammes of noseweight that will need to be added!

Andrew

[mr.charlse]

because i replaced all the wood, and thought it would be stronger that way.
would maybe gluing on "stiff" paper on both sides help reinforce?

[mr.charlse]

the wings have been polished now, and only need priming before covering.
I glued shims to the root ribs to get some dihedral, because i have heard so much good things about the wonders of dihedral .



Here you can see the shim.

[Phugoid]

Your plane will fly much better with a tail as designed, you are adding a lot of weight without adding much strength..... plus you are also adding weight where you really don't want it.

The best way to get your dihedral is to tilt the root rib, your method is valid but won't be as strong since you won't have full face contact between the rib and the fuselage.....

[ADW 123]

you wont want your tail pieces heavy at all. too fragile i thought they would break easy and then we are in a world of pain. phugoid has a point...

[mr.charlse]

Since basically everyone has told me to, i will build the tail as designed.
But if the "built up" tail becomes more heavy than the all balsa tail with the stiff paper reinforcement, then i will use the lightest.
I also probably forgot to mention that i am using sharpened birch dowels trough the fuselage for reinforcement.

[ADW 123]

i also noticed how in some parts of your wing, the stringers dip down below the ribs because notches are too deep. i usually like to cut them deep, and a little skinnier than i need. then, you put a pin into the notch but just next to the stringer. this pushes it to the side in case the notch is a little too big. this way, you can pull it up to be in line with the rib.

[mr.charlse]

I have been taking a little brake from building (a lot of paper work and medical stuff you have to do to get a pilot training permit in Sweden, especially if your thirteen)
but i have started building again now, will post pics as i progress
-Mr.Charlse