R

RV_7A

Well Known Member
Anyone using them in certain areas to save a little weight in their aircraft? Such as linkages, mounting etc... I'm hearing that using them in high load areas would not be in best interest. Any thoughts on what they could be used on?

-Jeff
 
I had a titanium tailwheel spring for my -8 originally, but it didn't work out as expected. Instead of trying to figure out if it was a heat treat issue or whatever, I just went back to the steel spring.

The thing that would concern me with fastner substitution is knowing that they are what they say they are. It's one thing to substitute one fastner for another when you're sure of what is needed and what you plan to use.

I use quite a few alternate fastners in my plane, but all of these were in very low stress, low criticality applications (if it breaks, do I die). 99% of the substitutions I made were stainless screws for steel.

Just can't think of may locations where this would save much weight, though.
 
"if it breaks, do I die"

Isn't that the main question anyone should ask when deviating from the stock plans?

I sure do.
 
On bicycles, ti hardware weighs about half of the steel stuff. I can't imagine half the weight of some/most of my plane hardware would really add up to much. It also costs a FORTUNE!

The big issue is strength and I don't think tensile strenth of the metal is the whole story. AN hardware has rolled threads, does ti? Seems like a complete waste of cash and an unneeded risk. JMHO.
 
Titanium bolts

I have substituted 95% of my "bolts" with Titanium bolts, or lockbolts in any permanent installations that wont be dissasembled...but, I dont recomend "across the board" interchangability to everyone. I happen to make my living as a structural specialist on large transport type aircraft, and have infinite access to the engineering/interchangability data used by Boeing,Airbus, ect. Most of the AN bolt used on RV's are fairly low strength(approximately 95,000 psi shear strength) and are safely repalceable with other equivelant aircraft fasteners. The big birds are going virtually 100% Titanium to replace alloy steel fasteners for two reasons: weight and corrosion resistance. Now, an RV may shed a couple pounds at best,however, a 747 will be several hundred.....I only used them because I have access to a lot of surplus that would otherwise go in the trash...and TITANIUM sounds cool! Please, make sure you have the right supporting data for any fastener substitutions...as I have.

Bill...RV-4 "titanium"
 
mgomez said:
Are titanium bolts lighter? By how much?
Click to expand...
The big birds are going virtually 100% Titanium to replace alloy steel fasteners for two reasons: weight and corrosion resistance. Now, an RV may shed a couple pounds at best,however, a 747 will be several hundred..... Please, make sure you have the right supporting data for any fastener substitutions...as I have. Bill...RV-4 "titanium"
Click to expand...
As "titanium" Bill well knows, titanium bolts are dramatically lighter and far stronger than the common AN bolts found in general aviation. He also knows the NAS 673 are uniformly .1890 in diameter and have no problem being inserted into every rod end bearing and predrilled spar hole in Vans designs! In fact, you would be hard pressed to find ANY common AN bolts used in modern combat jets. IF you could find...and that is a very big IF... you could find DOCUMENTED NAS 673 and NAS 674 to replace the AN3 and AN4 bolts you would enjoy a significant weight savings, a much stronger fastener and a more precision and naturally corrosion resistant fit. My own Google searches have indicated that some titanium bolts can be had through parts suppliers of high end state-of-the-art race cars. If anybody knows where NAS 673,674 and 675 bolts can be found...please share it with us.
 
Thanks guys. I too have done the research on my set of NAS6403 bolts since posting the question. They offer 160,000 PSI tensil strength and 95,000 PSI shear and can be used in applications up to 500 degrees. AN bolts only offer 125,000 PSI tensil and 75,000 PSI shear. And like Bill said above they save weight. 50% lighter to be exact. Every little ounce of weight savings on an RV is wonderful IMO. Is it economically viable? Maybe. If you can get the hardware for a reasonable cost. I have found lots of useful new hardware on Ebay at great prices.
-Jeff
 
You must log in or register to reply here.