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Thread: Titanium Bolts ?

  1. #1

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    Titanium Bolts ?

    I am Looking at replacing some steel AN bolts with titanium bolts on a cub, thinking of bolts for the, engine mount, tailwheel, landing gear, propeller etc.*Any particular applications to avoid?*What grade ? ti6ai4v ? Thanks.

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    Gordon Misch's Avatar
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    Not to be rude, but why? Honest question - - -
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  3. #3
    fabricfan's Avatar
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    Some bolts shouldn't be as rigid as titanium.

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    Gordon Misch's Avatar
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    Titanium is not as stiff as steel. Modulus of elasticity for steel is approx 200 GPa and titanium approx 105 - 120 GPa.

    http://www.engineeringtoolbox.com/young-modulus-d_417.html
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    Quote Originally Posted by Gordon Misch View Post
    Not to be rude, but why? Honest question - - -
    Weight....

  6. #6
    Crash's Avatar
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    I take back my first post. Here is a more reasonably priced source for Ti bolts.

    http://store.mettec.com/category/276

    http://store.mettec.com/category/284

    Take care,

    Crash
    Last edited by Crash; 01-12-2014 at 06:51 PM.

  7. #7
    irishfield's Avatar
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    F'n with fate comes to mind.... do your homework. AN hardware is strong enough to hold it... yet soft enough to bend vs shear off when needed the most. For the sake of 4 x AN8 bolts and 4 x AN5 bolts I wouldn't be messing with it.

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    Dave Calkins's Avatar
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    Quote Originally Posted by Wolf Cub View Post
    Weight....

    Wolf Cub, have you exhausted all the other means of weight savings on your airplane? Are all the aerodynamic tricks accomplished to make it best?

    ...or is there some other reason? (I don't know you or your airplane, so the context of your quest is unknown to me. )

    ....with all due respect I ask these questions. I had never heard of someone wanting Ti hardware on a Cub. Thanks. D

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    Thanks Crash,
    I have had good luck ordering from Met-Tec, *the bolts are well made and have rolled treads-Unlike some of the junk ti bolts available. I haven't run them on The landing gear, engine mount, or prop, but my research hasn't come up with any reasons not to yet? Maybe galling with non ti nuts or flange bushings ?

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    Quote Originally Posted by irishfield View Post
    F'n with fate comes to mind.... do your homework. AN hardware is strong enough to hold it... yet soft enough to bend vs shear off when needed the most. For the sake of 4 x AN8 bolts and 4 x AN5 bolts I wouldn't be messing with it.
    Thanks, This is just part of the homework. The metal comes in many different types, ti has some shear issues.. Will be careful on the F'n with fate.

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    Dave,

    No, but Most Means within my means and for it's intended use. No electric, minimal interior, carbon fiber, etc. I am always looking for new ounces. Ti hose clamps can save up-to 40% vs stock . I believe the only thing you can add to a cub is weight. Thanks.

  12. #12
    Dave Calkins's Avatar
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    ..thanks for the answer.

    Can you tell us more about your flyin' machine? Please

  13. #13

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    I run titanium bolts in my snowmachine there about half the weight of a steel bolt. There expensive but have held up great. Google "titanium bolt strength chart" grade 5 titanium is quite strong.
    Last edited by Ak; 01-12-2014 at 10:10 PM.

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    All my pulley bolts are ti. and my tail wheel to spring is ti. In fact I even used the basket or ashtray type lock nuts on most everything because they are a lot lighter. I know this saved some pounds on my SQ-2.

  15. #15
    Cub junkie's Avatar
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    Don't forget the anti seize. Ti threads like to gall real easy.

  16. #16
    DesperadoPilot's Avatar
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    I have found that the easiest way for me to save on weight is to back away from the trough every once in a while.....
    I fly IFR (I Follow Roads).

  17. #17
    nanook's Avatar
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    Is this a joke?

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    I think one might be going a little overboard if one starts trimming the fat with simple hardware, especially on an aircraft that already has so little hardware. This makes me feel guilty for daring to leave 4 and sometimes 6 threads showing after tightening the fastener as opposed to the textbook 2 threads (ie, excessive fastener length).

    Seriously though, if you intend to use Ti, please bear in mind that electrical potential difference is quite high when compared to steel and aluminium (it's considered a strong cathode) as opposed to aluminium which (is rather anodic).

    Galvanic corrosion plays a large factor in assembly, often that is why the industry standard is what it is.

    Like some other conventions; Aluminium is a better conductor than copper and weighs less, but copper is the standard for conductors, because Aluminium would strain harden and it's very susceptible to corrosion (which is critical).

    This means Ti is an outstanding material with no doubt oodles of great applications, but not worth the headache when it comes to collateral implications.

    My 2c
    Pete

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    I have said this to many people, to hell with the weight,how many airstrips will 20lb be the difference between life and death.Stay with the tried and proven methods.The ultimate question is will this aircraft hold together in a serious turbulence problem.I have flown all types of aircraft world wide in all types of weather strip lengths etc.Never have I run short of takeoff distance,but many a time have I thought,"I hope this girl holds together in this turbulence."Might I suggest if we are worried about weight work on your diet.It may also save you from an inflight incapacitation.

  20. #20
    meinster's Avatar
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    Hear hear

    Quote Originally Posted by ron View Post
    I have said this to many people, to hell with the weight,how many airstrips will 20lb be the difference between life and death.The ultimate question is will this aircraft hold together in a serious turbulence problem.I have flown all types of aircraft world wide in all types of weather strip lengths etc.Never have I run short of takeoff distance,but many a time have I thought,"I hope this girl holds together in this turbulence."Might I suggest if we are worried about weight work on your diet.It may also save you from an inflight incapacitation.

  21. #21
    Dave Calkins's Avatar
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    I would still love to hear about WolfCub's Cub.

    Ti hardware on a Cub ain't for me, but I have the stuff on my bicycle, and........he wasn't asking me if I wanted Ti hardware on MY Cub.

  22. #22
    nanook's Avatar
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    Just because you're experimental (is he?) doesn't mean you want to experiment with putting Ti bolts in structural applications. Wing/strut attach, engine/prop, and landing gear steel AN bolts are a proven and known entity, Ti bolts are not. Do you really want to be the idiot that finds out why this is a bad idea? These types of applications should be tested in a controlled environment. You find out if it is going to fail without sacrificing yourself (or the aircraft)in the process. All of your known torque values for AN steel, would have to be recalculated for Ti in the testing process. The galvanic properties mentioned above would also have to be addressed. + many, many other issues come to mind....good luck if you go that route...

    Palhal, you state you are using ashtray or basket lock nuts? These are the pressed missile nuts? Hopefully not the pawl nuts
    Last edited by nanook; 01-13-2014 at 04:14 PM.

  23. #23

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    Pete
    you sure Aluminium is a better conductor than copper?
    I have a heavy cub, but If I had the weight religion going strong I think bolts (LENGTH, THIN WASHERS, JET NUTS) would be a place you could save several LBS. Heck I carry extra gear,and tailwheel bolts, so i am a sinner when it comes to weight. The real question to ask is do we really need the strength we have if the plane is light? Tailwheel bolt is one I would replace (heck I saw some kid with just a pice of plastic back there one day) I need all I can get on my gear cause I have been known to bounce.

    DENNY

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    Quote Originally Posted by ron View Post
    I have said this to many people, to hell with the weight,how many airstrips will 20lb be the difference between life and death.Stay with the tried and proven methods.The ultimate question is will this aircraft hold together in a serious turbulence problem.I have flown all types of aircraft world wide in all types of weather strip lengths etc.Never have I run short of takeoff distance,but many a time have I thought,"I hope this girl holds together in this turbulence."Might I suggest if we are worried about weight work on your diet.It may also save you from an inflight incapacitation.
    Always seemed the other way around to me. I've never worried about the aeroplane even while getting a pounding, but pedalled a few times on take off and given a few places to land away wishing I had five or even three mph less stall speed.

    What size engine you putting in your plane Ron?

    Cheers,
    Andrew, flying an underpowered 150 hp Cub in the North Island.

  25. #25

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    Quote Originally Posted by Wolf Cub View Post
    I am Looking at replacing some steel AN bolts with titanium bolts on a cub, thinking of bolts for the, engine mount, tailwheel, landing gear, propeller etc.*Any particular applications to avoid?*What grade ? ti6ai4v ? Thanks.
    http://www.vansairforce.com/communit...d.php?t=108374
    Check post #8 in particular.

    Andrew.

  26. #26
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    To answer your question, copper has slightly better conductivity than Aluminium.

    Losses due to resistivity on Aluminium were considered acceptable for these purposes when aluminium was used, given the weight savings (which of course would be astronomical in a large Direct Current installation), regrettably the repercussions were less than desirable; oxidation on terminals caused poor grounds = constant problems and conductors would work harden (in a high vibration environment) over time and fail.

    Copper is the next best thing to silver or gold (affordable, relatively common and lighter than those two), in using Alternating Current on more sophisticated aircraft they were able to do away with the ridiculously thick gauges of copper they would have had to use.

    Hence copper is the standard.

    I'm pretty sure a similar development exists for steel hardware.

    Quote Originally Posted by DENNY View Post
    Pete
    you sure Aluminium is a better conductor than copper?[COLOR=#333333

  27. #27
    skywagon8a's Avatar
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    Quote Originally Posted by MainlandCub View Post
    http://www.vansairforce.com/communit...d.php?t=108374
    Check post #8 in particular.

    Andrew.
    Look at post #13 also.
    [/QUOTE] I see no problem substituting non structural hardware with titanium or gold if you must but unless you fully understand the requirements to use titanium bolts in a load bearing capacity, I would stay away from those.
    It has been pointed out by a previous poster but substituting load carrying
    AN bolts with titanium is a very bad idea in the hands of most experimental kit builders.
    Titanium bolts require Precision machined holes with very tight tolerances and will not tolerate any king of abuse. AN hardware is very forgiving and a bolt may bend and twist before breaking.[/QUOTE]
    N1PA

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    Quote Originally Posted by MainlandCub View Post
    Always seemed the other way around to me. I've never worried about the aeroplane even while getting a pounding, but pedalled a few times on take off and given a few places to land away wishing I had five or even three mph less stall speed.

    What size engine you putting in your plane Ron?

    Cheers,
    Andrew, flying an underpowered 150 hp Cub in the North Island.
    Andrew,without applying mathematics you need a lot of weight reduction to achieve your objective of a 3-5 mph approach speed reduction.I would suggest carry less fuel,loose body weight or most importantly do not land if in doubt.My last 3 cubs were 150/160 hp.The one I am building is a 195.I wish I had stuck to 150hp with this one,now I am building the cowls!
    Last edited by ron; 01-14-2014 at 03:13 PM.

  29. #29
    Gordon Misch's Avatar
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    Cautions from NASA -

    "Titanium fasteners should be selected only where their advantages relative to steel are
    essential for an application and should never be employed as single point failure tensile
    fasteners. When using titanium fasteners, engineers must measure all torsional friction
    loads, torsional preloads, and torsional breaking loads. If one decides to use these alloys,
    he/she should expect to be especially scrupulous in the design and testing of its
    application. MSFC-STD-557 should be consulted for usage criteria."

    http://code541.gsfc.nasa.gov/Uploads...TIP%20133R.pdf
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  30. #30
    SchulerJL's Avatar
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    As an orthodontist, I deal with Titanium daily, wires-braces. Titanium is very brittle, it give no warning of failure,it just snaps - under very little force once a critical area - a nick - is created. Kind of like glass, you scratch glass and it fails on the etched line. There is no bending titanium, just breaking.

    I think all of these threads on making your plane lighter should start: "My BMI is... and I'd like to cover my plane with feathers to save weight". We know that if the BMI is 18.5 or below the poster has done everything to reduce His/Her personal body weight and then can seriously reduce airplane wight. Put yourself on a diet before you put your plane on a diet.

    P.S Don't know you Wolf Cub - you could be a skinny bean pole - just an observation of previous threads.

  31. #31
    Gordon Misch's Avatar
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    Here is an old (1957) rather detailed report by North American Aviation, as published by NATO, regarding manufacturing processes involving titanium, the associated manufacturing and service difficulties, and their resolutions. I knew it was a somewhat temperamental material, and the detail in this report is interesting to read. I sure as heck would not use Ti fasteners as primary structure on a Cub, experimental or otherwise.

    http://ftp.rta.nato.int/public/PubFu...AGARD-R-96.pdf
    Last edited by Gordon Misch; 01-15-2014 at 12:44 AM. Reason: typo
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  32. #32
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    AOSS has titanium main strut and adjuster and there are a lot of people using it in extreme load conditions everyday now. Not saying it is right or wrong just an observation.

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    lots of interesting opinions, diet advice,plenty of concern, and even a resume of sorts. The plane will be experimental.*

    "wanting to be the idiot that finds out why this is a bad idea? These types of applications should be tested in a controlled environment.."

    I am not planing to be an " idiot" Thanks, for the concern. I am looking for info from testing in a controlled environment for a potential experimental application.*

    Thanks for the links some interesting data.

    *My BMI is low. So not a nutrition question..

    " I have said this to many people, to hell with the weight,how many airstrips will 20lb be the difference between life and death.Stay with the tried and proven methods.The ultimate question is will this aircraft hold together in a serious turbulence problem.I have flown all types of aircraft world wide in all types of weather strip lengths etc.Never have I run short of takeoff distance,but many a time have I thought,"I hope this girl holds together in this "

    Turbulence is a concern for sure ! I have seen it bend a cub. an issue for some bolts, but probably not the landing gear, different type of loads and other concerns. One transport category STOL cargo plane has it's wing attached with 4 small hollow Ti bolts. Engineered to the hilt I would think. *I find it *common to put a cub into spots that it can't take off from, due to strip length at it's landing weight, different application perhaps. 20 lbs itself would not make a huge difference (To me a huge difference is a plane length or two) but this research is not about taking 20 lbs off of a 1200+pig. It's about trimming the fat for a 200+ lb difference. As Greg, and Palhal can relate to. Please understand that I am not *trying to start a pissing match saying one cub is any better than another, I am just looking for some info on the different applications of Titanium bolts on a cub Thanks again for the posts and links * * *

  34. #34
    Dave Calkins's Avatar
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    ...I still wanna hear about this airplane.

  35. #35

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    According to 2013 Aerospace Industry Trends Oct. 13 conference.
    Airline transport uses 70 % of titanium production.
    Ti compromises 10% by weight(raw) of new aircraft.
    66% of that Ti usage is in the airframe
    Ti usage is growing at 4.6% per year(aircraft production).

  36. #36

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    If you want to lose 200# weld up a new fuse out of Ti tubing and cover your plane with Oratex or something else light!

  37. #37
    SchulerJL's Avatar
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    Quote Originally Posted by Den View Post
    If you want to lose 200# weld up a new fuse out of Ti tubing and cover your plane with Oratex or something else light!
    I think you would loose $200,000.00 on the Ti tubing in addition to the 200#

  38. #38
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    If you took all the hardware in the entire plane and threw it in a bucket how much would it weigh? 10 lbs would be a lot of bolts and screws. If you start subtracting the ones you would not touch then at best guess you would likely save 2#'s on the high side. That would be my guess anyway. I wonder how far off I am.

    But in the vision of Burt Rutan: "If you let go and it doesn't go up, then it is too heavy."

    Tim

  39. #39

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    Quote Originally Posted by MN_flyer1 View Post
    If you took all the hardware in the entire plane and threw it in a bucket how much would it weigh? 10 lbs would be a lot of bolts and screws. If you start subtracting the ones you would not touch then at best guess you would likely save 2#'s on the high side. That would be my guess anyway. I wonder how far off I am.

    But in the vision of Burt Rutan: "If you let go and it doesn't go up, then it is too heavy."

    Tim
    The fable goes that Leo Loudenslager when he built the Laser (or Lazer), in one of his efforts to reduce weight, cut off the excess length of all the bolts. The cuttings were put in a bucket and weighed at the end of the project. The weight of off-cuts was 15 lbs.

    There's gold in them there hills…………….

  40. #40
    Dave Calkins's Avatar
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    I don't buy that story.

    I stood close enough to touch Loudenslager's Lazer in the late 80's. I bet there ain't 15 pounds of full-length bolts in the whole airplane. Never mind just the "cuttings".


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