Question about a wing spar

[Gerald Sam]

Sorry , i'm a newbie in a experimental aircraft, but i want to know about this. I hope there is someone can help me about this. I hope I can more understand about homebuilder aircraft with this forum.

I have a question about a wing spar . Anyone know how to calculation of formula wing spar with aluminum, and what the best aluminium alloy for wing spar and body? thanks

[steveinindy]

I have a question about a wing spar . Anyone know how to calculation of formula wing spar with aluminum

There are plenty of books on the subject. "Stress without Tears" is a good starting point but it's not a book that should be considered all inclusive.


what the best aluminium alloy for wing spar and body

It depends on what the aircraft is going to be used for, where, etc. Also, keep in mind that what is a good alloy for one part (such as the spar) may not be the best option for another such as the skin. Even different sections of skin (the top and the bottom of the wings for example) may need to be made out of different alloys in a few cases because one side of the wing will be in compression whereas the other will be in tension.


Just out of curiosity is English a second language for you? If so, a lot of the technical articles may give you trouble. Even as a native speaker, I often find some of them hard to follow.

[Gerald Sam]

if a "Simplified Aircraft Design for Homebuilders" the book is better or same

[WLIU]

In the aircraft that you commonly see on the ramp, 2024T3 or its siblings is the most common aluminum alloy used for primary structures like wing spars. It needs to be protected against corrosion, but it is otherwise the alloy that has the best trade-offs between strength, weight, fatigue, and cost. You will see some designers use 6061 as it is more corrosion resistant and costs less, but you trade away some strength so you need beefier parts.

All of the materials properties info that you need is in the Aircraft Spruce catalog and on the web in various places. You plug the values into the formulas that you will find in the text books. I will note that you will be using standard sizes of raw materiels so plan on using the next size up from the theoretical ideal, allow for some loss of strength due to rivets and bolt attachment, and plan on at least a 150% safety factor (maybe 200% for a new guy).

When you get done, hang a bunch of sand bags on your structure and verify that it flexes without taking a set or failing.

Best of luck,

Wes
N78PS