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Lightening holes in the VS

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dweyant

Well Known Member
I'm just starting to put together the vertical stabilizer.

I started clecoing the parts together last night, and the instructions talked about drilling out lightening holes if I desired them.

So, two questions, why would I want/not want to drill the holes?

If I do drill them, what is the best way/tool to drill them with? Will a bi-metal hole saw work?

Thanks,

-Dan
 
Last edited by a moderator:
I believe in lightening any where it's possible. Those holes are right on the neutral axis, so the material you're removing provides almost no strength. I can't think of any pros to leaving it there.

I used a fly cutter.
 
You must have an older kit, since the newer ones already come from the factory with the VS spar doubler lightening holes prepunched.
 
bruceh said:
You must have an older kit, since the newer ones already come from the factory with the VS spar doubler lightening holes prepunched.
Click to expand...

I bought the kit second hand. The gentleman I bought it from took original delivery in 2003.

What is the point of having the lightening holes in the spar? Just weight savings?

-Dan
 
Pro: Weight savings
Con: Extra time spent on them

Someone had an interesting statistic that if you took every opportunity that Vans published to lighten parts, you'd only save a few ounces of weight on the whole plane. Nevertheless, I take every option allowed. :)
 
Precision hole saws

My empennage was purchased in 2003 and did not have the VS spar holes drilled. I used these precision hole saws from US Tool
http://www.ustool.com/store/cart.php?m=product_detail&p=3567
Weight saving was my reason, and of course it's the principle of weight saving rather than saving a great deal of weight.
If you drill the holes, I'd suggest the precision hole saws shown above, not the hardware store hole saws for wood (they don't cut round holes in aluminum). Using a precision hole saw, all you have to do is debur the hole edges and polish the bore.
 
I put the lightening holes in my VS. I remember at times using both hole saws and fly cutters on various parts. I forget which I used on the VS but I do remember weighing the parts after I was done. The weight of those little aluminum discs was truly negligible but what the heck I had never used these tools on aluminum before and it was a good learning experience. Didn't take long either.
 
N526JS said:
I put the lightening holes in my VS. The weight of those little aluminum discs was truly negligible
Click to expand...

The weight of those little discs may have been negligible but by lightening every little item that Vans suggest adds up. It may be extra work now but when you get your hard work into the air, you will know then it was all worth it :D
 
Yes Racer, a lot of little things add up which is why I take every opportunity to "add lightness". Especially since I have a C/S prop, full panel, A/P servos and other optional items. My wings are not on yet and I have a way to go before I weigh the project. I am crossing my fingers on that outcome. So for the original poster I would recommend the lightning holes.
 
Lightning holes

I have an older -8 kit, and someone shared with me a photo of the plans showing the size and location of the VS lightning holes, but of course, now I can't find it. . Anybody have it? Thanks.

Also has anybody used a large dimple die for the lightning holes like on ribs for strength? Or just a flycutter?
 
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