Mike James

I suggest this thread, to serve one simple purpose... that is to exist as a permanent reference for comparing model parameters. How about sharing some of your basic specs here, for both kits and original designs, and we can all refer to them whenever we like?

An example post might look like this:

Name My "XXX" Design
Type Aerobatic
Length 66 inches
Span 68 inches
Wing area 820 sq. inches
Engine: YS .91 4-stroke
Fueled Wt. 8.5 lbs

Remarks: Flew great and very smooth with aerobatics

If you are as geeky as me, you could also add such things as wing and tail root and tip chords, airfoils, tail area, CG, wing sweep angle, etc.. This would be great for both kit bashers and designers, like an online reference book. Anyone interested?

irishcarbomb

My Feedback: (4)

I think thats a good idea. as soon as i bring my disks home, i'll post some specs.

any luck with that CG changer?

Mike James

Hi again!

Good! Looks like you and I are in the minorty right now, but I'll post some more specs too, this weekend. Maybe once this thread gets enough data in it, people will see it's value as a reference. Here are the specs for the design in the attached photo.

J-45 Specifications (as of 02-21-01) (Pattern version)

All Eppler 168 airfoils
Length (Nose ring to Rudder t.e.) (In.) 66"
Wing Span (In.) 68"
Root Chord (In.) (Projected is 1" more) 16"
Tip Chord (In.) 8"
Wing AR 5.6666666667
Wing MAC (In.) 12"
Wing Area 816 sq. in.

Horizontal Stabilizer Span (In.) 24"
Horizontal Stabilizer Root Chord (In.) 10"
Chorizontal Stabilizer Tip Chord (In.) 6"
Horizontal Stabilzer AR 3
Horizontal Stabilizer MAC (In.) 8"
Horizontal Stabilizer Area 192 sq. in.

Vertical Stabilizer Span (Height) (In.) 11.25"
Vertical Stabilizer Root Chord (In.) 20.25" (Projected to fuselage bottom)
Vertical Stabilizer Tip Chord (In.) 6"
Vertical Stabilzer AR 0.85714285714
Vertical Stabilizer MAC (In.) 13.125"
Vertical Stabilizer Area147.65625 sq. in.

Moment Arm (Wing MAC to Horizontal Stabilizer MAC) (In.) 35

Expected Weight 128 oz. (8 lbs.)
Expected Wing Loading 22.588235294 Ounces per sq. ft.


I'm still sanding, filling, sanding, filling, etc. on the plugs for my new aerobatic design, (photo attached) but am interested in trying the CG changer once it's flying this summer. What are you up to?

irishcarbomb

My Feedback: (4)

Had to put my design on hold due to a architectural project in school. but thats finished now, so full speed ahead. probably going to order some wing cores soon. will try and post some pics of the plan views later today, but i don't have access to any 3D stuff.

irishcarbomb

My Feedback: (4)

heres a side view of the fuse for my design.

some specs:

wingspan(in): 58"
length(in): 47-97/256"
root chord(in): 12"
tip chord(in): 6-1/4"
airfoil: S8035 14% thickness
wing area(in^2)(incl. ailerons): 490.6328125"

horizontal stab span(in): 17-5/16"
horizontal stab area(in^2): 120.0078125"(incl. elev)
root chord(in.): 6.98828125"
tip chord(in.): 4.5"

vertical stab height from fuse bottom(in): 8-3/4"
vertical stab area(in^2): 54.59375"(incl. rudder)
root chord(in.): 13.3203125"
tip chord(in.): 4"

not sure how to calculate much else...
would like some hle figuring out MAC and wingloading, if possible.
also, what is Wing AR, Stab AR?

irishcarbomb

My Feedback: (4)

heres a side view of the fuse for my design.

some specs:

wingspan(in): 58"
length(in): 47-97/256"
root chord(in): 12"
tip chord(in): 6-1/4"
airfoil: S8035 14% thickness
wing area(in^2)(incl. ailerons): 490.6328125"

horizontal stab span(in): 17-5/16"
horizontal stab area(in^2): 120.0078125"(incl. elev)
root chord(in.): 6.98828125"
tip chord(in.): 4.5"

vertical stab height from fuse bottom(in): 8-3/4"
vertical stab area(in^2): 54.59375"(incl. rudder)
root chord(in.): 13.3203125"
tip chord(in.): 4"

not sure how to calculate much else...
would like some hle figuring out MAC and wingloading, if possible.
also, what is Wing AR, Stab AR?

irishcarbomb

My Feedback: (4)

here's the top view

Mike James

Hi Uproar,

AR is "Aspect Ratio". For example, a wing with a chord of 10 inches and a span of 60 inches has an AR of 6. (span/chord) Most "sport" planes have an AR of 5 to 6. Jets have less, gliders have more.


MAC (Mean Aerodynamic Chord) is: (for a simple single tapered wing)

Root Chord + Tip Chord/2 The point on your wing where this occurs is where you measure the CG from. (i.e. "33% MAC")


Wing loading (in oz./per square foot) is gigured like this:

Weight/wing area X 144 (144 square inches in one square foot)

Let's say your 5 lb. (80 ounces) plane has 500 sq in. of wing area.
80/500=.16 (This is actually the wing loading per square INCH)
.16 X 144 = 23.04 ounces per square foot wing loading.