Limawer

Hello,
I am currently attempting to design and build a Cessna 170 with a 75" wingspan. I am taking most of my information from the plan of Guillow's Cessna 170 24". With the help of Turbocad I have basically finished my wing plan, but want to start my fuselage plan. And I was wondering what to set the wing incidence angle at, the amount of downthrust, the amount of right thrust, and the amount of stabilizer incidence? Are there standard angles for this plane? On Guillow's plan I can get a water line, but no downthrust or right thrust for the engine is given. I can probably figure out the wing and stablilizer incidence angle from this plan, but would this plan show accurate angles for the plane I am creating? How much difference does all of these angles make?

Limawer

aerowoof

a lot will depend on what engine and what airfoil you choose.

Limawer

I planning on putting a .51 ST or a .61 ST two-stroke engine in it. As for the airfoil it is very similar to a normal trainer airfoil, maybe a little bit thinner.

CoosBayLumber

My Feedback: (1)

I fly and market plans for the old Berkeley Cessna 170, and can tell you the noted power is a bit much. This A/C was not supposed to fly inverted nor like a rocket. A .35 (or smaller) would be more appropriate.

Wm.

John 38

Hello Limawer,

a long time ago I built a 84" Cessna based in the 42" Golderg Cessna, as a basic trainer for air cadets, which was very successful.

It had a 48 surpass 4 stroke and was built fairly light at about 4 lbs. It flew a dream - very scale like and sounded just right with the 4 stroke.
I hope to scale up again to about 9/10 ft as the Cessnas look great in the air if flown to scale. It would loop OK on the 48. Aileron rolls not possible as in interest in keeping lo cost and weight it had no ailerons

the wing was a standard clark y section and the bottom was parallel to fusalage datum line and elevator line. ie , everything neutral and some slight down thrust on engine. However, if you are not sure , then I suggest about +2 deg for wing ( if clark Y)and if it is too much you can always pack up trailing edge wiyhout it showing too much, whereas it is more difficult to pack up leading edge as if you build to scale, the front of wing will be built into cabin and relatively fixed.

I think the pico or top flite cessna had symmetrical wing and was neutral to fuz datum line, but these were built heavier for aerobatics and had more power

the wing needs a little dihedral to look right - a friend built another of my 84" and it didn't look right with the flat wing

have you tried checking with any of guys with some of the latest larger cessna kits ?

hope this helps

John

Mike Emilio

Limawer . .

The 50 year copyright on the Berkley 170 plans is up!
Give me your address and I'll mail you a copy. . . . No charge!

Mike Emilio

Got your mailing address yesterday. Free plans will be in the mail today.

Happy "un-birthday"

acflier

? Do you still have acess to the plans youi sent "Limawer"?
If so; would you mind sending me a coppy?

feihu

Limewer:

Wing and tail angles and downthrust angle all make a big difference if not set properly.
I assume you will be using ailerons, so you should set the dihedral angle like the full size airplane at about 1 and 1/2 degrees.
Draw a fuselage horizontal axis thru the engine prop shaft and use this as your horizontal reference line.
If the bottom of your wing is flat, set the flat section parallel to the reference line.
Set the horizontal stabilizer parallel to the reference line.
Set about 2 or 3 degrees of downthrust for your .51 or .61 engine as a starting point. You may have to readjust this angle after flight tests. You might want to use perhaps 2 degrees of right thrust, but I prefer to leave the sidethrust at zero and use rudder control.

feihu