Monday, March 2, 2009

Will it climb?





I created new spreadsheet for calculating climb rate at sea level. I created it to investigate single engine situation in a quick way.

You can download it from here:
climbcalc.ods

WARNING! You have to know what input values you enter, otherwise the results will be bogus. For example the value of K depends on aspect ratio and e.

2 comments:

Exo Cruiser said...

Ok, I did not check the values or formulas, but did you trop one engine? 200 hp or 100 hp?

If you are using the formulas correctly and not assuming anything too optimistic, you should get reasonable results.

Yes, the procedure to design a small propeller driven aircraft is shown in several sources. For example the following sources have it done with clear numbers:

- Anderson, Aircraft Performance and Design
- Raymer, Aircraft Design - A Conceptual Approach

I find it most difficult to estimate the wing placement with some error marginal. One way is to shift the heavy battery either in front or back and/or leave some room for the engine to be moved forward (push) or backwards (pull).

I use the static margin to fix the wing.

I was just reading about the German Go 242 (WWII era) twin tail heavy glider which destroyed (flutter at high speed) it's tail, twin booms and wing. Killed a technician, the pilot jumped and survived (also some other people was killed during test flights). The design was fixed and it gained some popularity. Later it was transformed to Go 244 with engines.

Unknown said...

No, you can enter your own engine power and also now aspect ratio and e (updated the spreadsheet).

The equations are from Anderson obviously. (please see my earlier post, about my current library):

http://designaplane.blogspot.com/2008/04/reference-library.html

Or have a look at the wiki:

http://gforge.katix.org/gf/project/twinzygger/wiki/?pagename=ReferenceLibrary