Metric to imperial wing loading?

[Peter Young]

Hi all

I am considering buying a plane, but I can't make sense of the metric specifications. What I am looking for is a very slow flyer, similar to a Cub. I know Cub's have a wing loading of about 18 (is that onces per sq inch?). This plane has the following stats:

Length . . . . . . . . . . . : 1330 mm
Wing Span . . . . . . . : 1840 mm
Wing Area . . . . . . . . : 47 dm 2
Wing loading . . . . . . : 67g~dm2
Airfoil . . . . . . . . . . . . : NACA-2412
Weight . . . . . . . . . . . : 2200~2300g

Can anyone help me to convert 67 g/dm2 to imperial?

Many thanks

Peter

btw this is an IC plane if that makes any difference - a CM Pro cessna bird dog

[ChrisP]

As a Brit living in Germany I face this a lot !

The quickest way in your head is to divide by 3, which gives you around 22 ozs per sq ft. The actual answer is 21.96 ozs per sq ft.

1 ozs is 28.35 gms and 1 sq dm is 15.5 sq ins.
1 gm per sq dm is 0.3277 ozs per sq ft, so in fact you multiply the 67 by 0.3277.

If you're serious about a VERY slow flyer then this is not the model. My Bloody Mary probably meets your needs regarding flying speed and has a wind loading of 7.3 ozs per sq ft.
You really should be looking in the range of 10 or under. The 18 you mention is average for a pretty normal type I/C model. 22 is at the top end of the range that I fly electric.

[steve lewin]

Doesn't matter if it's Imperial or Metric, those numbers do not compute.

Weight 2300gm / Wing Area 47 dm^2 = 49 g/dm^2 or 16 oz/sq ft.

Either way it's not going to be a very slow flyer. Even 16 oz/sq ft is not a very low wing loading (stall speed around 15 mph).

Steve

[Bill Glover]

BTW another handy way to convert metric dimensions is to fire up MotoCalc. In 'options' pick 'metric', input the model stats in the airframe window (wing area, span, weight) , back to 'options', select 'imperial' and they are all converted for you :)

[GregG]

Convert does all the math for you. It's a free download and can be found here:
http://www.joshmadison.com/software/convert/

[Peter Young]

Thanks all for this advice. I'm looking for a very slow gas powered plane, so I suspect 16 oz/sq ft is not too bad.

Peter