Peter Y

Hi all

I am considering buying an ARF made by CM Pro (I assume a german company?). I want a very slow flyer, similar to a cub. This plane is a cessna bird dog. The wing loading is in metric and I don't know how to convert this to imperial. The details are as follows:

Length . . . . . . . . . . . : 1330 mm
Wing Span . . . . . . . : 1840 mm
Wing Area . . . . . . . . : 47 dm 2
Wing loading . . . . . . : 67g~dm2
Airfoil . . . . . . . . . . . . : NACA-2412
Weight . . . . . . . . . . . : 2200~2300g
Engine Required . . . : .40 - .46 (2-cycle)
: .50 - .60 (4-cycle)

Can anyone tell me how this compares with a traditional style Piper Cub for wing loading?

many thanks

Peter

MinnFlyer

My Feedback: (4)

Here is an on-line converter:

http://www.sciencemadesimple.com/conversions.html

Peter Y

Thanks Mike

I think my maths is letting me down - I'm assuming 47 sq dm is square decimetres, which is 728 sq inches. 2250 grams is 72 onces. So what is the wing loading? (or am I mistaken in thinking wing loading is weight over area?).

Peter

digger.10

So now just divide...

I get 79.38 oz. at 2250g, 1kg = 2.205 lbs / 16 (oz/lb)

divide 728 sq.in. by 79.38 oz.

result is 9.17 oz./sq.in. wing loading.

Should be a real floater...

Steve Lewin

Pardon me but you can't divide area by weight (sq in / oz) and get an answer in oz / sq in (weight / area) ! Anyway wing loading is always given in ounces / SQ FOOT so there's another conversion to do yet .

Steve

digger.10

I have been in Japan so long I have forgotten the Imperial system...! I was also bass ackwards on my first cup of coffee in the morning when I posted...NO EXCUSE!!! :stupid:

Yes Steve you are right, sorry Peter...

OK


79.38 ounces divided by 728 sq. in. is .10903846 ounces per square inch. We DO need to know oz./sq.ft. so multiply that by 144 and we have 15.70 ounces per square foot of wing loading.

Still not to shabby.

Edited: I don't know what you mean compared to a "traditional" Cub, the Great Planes Cub ARF specs state 19.9 oz./sq.ft wing loading. Anything under about 23 oz/sq.ft. and yer laughin'...

Peter Y

Thanks Digger and co for your sustained efforts to help work out the imperial wing loading for this plane. I agree it sounds like a nice slow flyer.

I agree 15.7 sounds like a mighty slow flyer. Its a great looking plane too, but I am very weary after reading all the bad reports here about CM Pro kits. (China made rather than german - wishful thinking I guess). Here's a pic to help explain my dilemma.

Thanks again

Peter