Arrow shafts

I have just discovered that one of the guys I work with is a keen Bow hunter, and so is his Daughter, I mentioned how useful Carbon-fibre arrows are to us as push-rods and he and his Daughter have given me some that are split at one end, but will be perfect for me after I cut off the splits etc.
My question..... He also gave me 30 or so Aluminium ( note correct English spelling..... ) arrows in similar condition, could I use these as pushrods ?
I only fly stunt for sport so saving a gazillionth of an ounce is not important to me, ease of use is.
BTW, any-one at KMAC want a CF arrow shaft? I can give away 3 or 4.
If so, PM me.

Dave,

Of course you can. Arden Zhang used them in his SkyWriter and won two world championships with them. (that must have been the reason he won )

Best method would be to machine end fittings from aluminum and provide one threaded end and one fixed end or make a left and right hand thread and make it infinitely adjustable.

Kim.

>Dave,
>
>Of course you can. Arden Zhang used them in his SkyWriter and
>won two world championships with them. (that must have been
>the reason he won )
>
>Best method would be to machine end fittings from aluminum and
>provide one threaded end and one fixed end or make a left and
>right hand thread and make it infinitely adjustable.
>
>Kim.

Kim,
many thanks for that..... yes, I thought it was OK, wondered if there were any hidden dangers.
Again, many thanks.

Dave,

The only thing I would be cautious about is that aluminum is obviously softer than carbon fiber.

You want to make sure that the pieces of rod that are held by the end fittings are concentric to the shaft centre line so that all forces run parallel to and along that line. You should also ensure that the shaft can not impinge on any fuselage formers or the stabilizer throughout its range of travel to preclude a bend being initiated. Make sure that the shaft is dead straight to begin with. Use ball links at both ends.


Kim.

>Dave,
>
>The only thing I would be cautious about is that aluminum is
>obviously softer than carbon fiber.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Obviously you have never tried to work 7075T6. There are all grades of aluminum.

>>Dave,
>>
>>The only thing I would be cautious about is that aluminum
>is
>>obviously softer than carbon fiber.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
>Obviously you have never tried to work 7075T6. There are all
>grades of aluminum.


Phil,

You know, I was going to consult you first before posting this but I thought a professional archer such as yourself would not want to be pestered by someone like me. So instead, I went to a well known archery web site and here is what it said about aluminum arrows. I realize that this does not carry the weight of your opinion but what the hey!


"All shafts have Pros and Cons:


Aluminum Pros:

More sizes to choose from so an archer may be able to get the best shaft without adjusting point weights.
Sometimes the initial cost is cheaper than carbon.
Made in much larger sizes for indoor league and money shoot line cutting abilities.
Tried and tested for years. ***

Cons for Aluminum:

The less expensive shafts are quite soft and bend easily.
Even the best quality will bend and need straightening.
Aluminum prices have continued to go up compared to Carbon coming down.
Many but not all Aluminum sizes weigh more per inch than Carbon shafts.
Each time an Aluminum arrow is straightened it looses some of its strength and memory. (so it will bend easier the next time)"

Glad you could find something to flap your gums about.


Kim.

When cutting the carbon arrow shaft cast off's to useable lengths (removing the split ends) it's best to use a high speed cut-off abrasive wheel and your Dremel type rotory tool. The friction from the cutting wheel will melt the resin ends of the carbon shaft which reduces the tendency for the shaft to split or continue splitting. The use of slow speed hand saws (Zona and the like) is not recommended. This is the rule I've been using when it comes to carbon fibre shafts. Any body else follow this thinking?
edit: Also protect yourself from breathing the dust!!!!

I have used a few aluminum arrow shafts for push rods in R.C. pattern planes with fiberglass fuselages.In that case there is a drawback. The daily temperature changes affect the pushrod length enough to throw off your neutral setting a noticable amount . Possibly this would be unnoticable in a stunt plane ,where your pushrod is maybe half the length ,and our hand position compensates for small amounts of correction. Keith Varley.

I would say that the changes is your nuetral settings is due to the fiberglass fuselage and not the aluminum push rods a 40 degree temp change in relation to the given length of aluminum tube or rod would be less than 0.010" and probably not that much. Which may make a difference on a RC plane but the fix is relative.

Scott

I'm a bow hunter too! That's why I took up C/L again, to may bent and broken arrows and nothing to do with them. If you use the aluminium arrows marked as "Super Lite's" you shouldn't have much of a problem with weight. If you want to know the weights you can go to Easton's web site and it will tell you the grains per inch for the differant sizes. Just measure the lenght and multiply by grains.


Go to eastonarchery.com/spineWeight/hunting/


The Duck

Oooop's, that should be Kirm Dog not The Duck (archery season is over and I'm having withdrawls)


Kirm Dog

There is a hybrid arrow shaft I have used in RC planes that is very light also. It has a thin wall aluminum core tube and carbon fiber outer tube. It works very well and is stiff and light. They are though much larger in diameter than an all carbon fiber pushrod to fit 4-40 ends so the fuselage must be larger.

When I started using fiberglass arrow shafts for pushrods Bob and Rolland McDonald showed me what they were doing and it worked very well without ball joints, though it would work with ball joints just as well. A wire pushrod the normal diameter was made to extend beyond the arrow shaft with what ever end fitting you wanted to put on it. The end to be in the arrow shaft was bent 90 degrees to the long axis and was cut off so it would just fit into the shaft. A hole was drilled about 1 1/2 to 2 inches down from the end of the shaft and thru one wall. We'd coat the inside of the shaft with epoxy, put the metal terminal end in and position it so the bent end came out the hole. Then a soft balsa block a couple of inches thick was pushed onto the end of the shaft. The shaft essentially cut its own perfectly fitting inner plug that at the same time was forced into the shaft and locked in place with the epoxy. The wood plug prevented the wire from coming out and held the terminal wire end in place and aligned, albeit along one wall of the tube. Never failed in any of the planes I know of. Flew to Super Tigre .60 ship with it. Lasted till I gave the planes away when I left stunt in the mid 80's. Still use the method sometimes in RC today.

Bob Branch

>There is a hybrid arrow shaft I have used in RC planes that
>is very light also. It has a thin wall aluminum core tube and
>carbon fiber outer tube. It works very well and is stiff and
>light. They are though much larger in diameter than an all
>carbon fiber pushrod to fit 4-40 ends so the fuselage must be
>larger.
>
>When I started using fiberglass arrow shafts for pushrods Bob
>and Rolland McDonald showed me what they were doing and it
>worked very well without ball joints, though it would work
>with ball joints just as well. A wire pushrod the normal
>diameter was made to extend beyond the arrow shaft with what
>ever end fitting you wanted to put on it. The end to be in the
>arrow shaft was bent 90 degrees to the long axis and was cut
>off so it would just fit into the shaft. A hole was drilled
>about 1 1/2 to 2 inches down from the end of the shaft and
>thru one wall. We'd coat the inside of the shaft with epoxy,
>put the metal terminal end in and position it so the bent end
>came out the hole. Then a soft balsa block a couple of inches
>thick was pushed onto the end of the shaft. The shaft
>essentially cut its own perfectly fitting inner plug that at
>the same time was forced into the shaft and locked in place
>with the epoxy. The wood plug prevented the wire from coming
>out and held the terminal wire end in place and aligned,
>albeit along one wall of the tube. Never failed in any of the
>planes I know of. Flew to Super Tigre .60 ship with it. Lasted
>till I gave the planes away when I left stunt in the mid 80's.
>Still use the method sometimes in RC today.
>
>Bob Branch


I too have access to shafts as i have relation with a archery shop. I do almost the same thing as bob here but i use a harder wood like dowel rod instead of balsa and use the same glue as they use on the shafts in the bow shop. I think its called tiger glue. It sets up fast just like super glue but the thin is like a med or thick to us. Once set it will not let lose at all. Also i use a tubing cutter like you would to cut copper tubing it wont split or make any dust to breath on the carbon fiber shafts.

Steve

Obviously, aluminum requires tremendous amouts of electricity to produce, thus giving off greenhouse gas, destroying the ozone layer, and future contributing to man-made controllable GLOBAL WARMING.

Even if your electricity comes from Hoover Dam or Niagara Falls, you are still a guilty ozone-killer - repent you sinner!

If you love AL GORE, you will use carbon fibre and boycott all alumiunum products.

>Obviously, aluminum requires tremendous amouts of electricity
>to produce, thus giving off greenhouse gas, destroying the
>ozone layer, and future contributing to man-made controllable
>GLOBAL WARMING.
>
>Even if your electricity comes from Hoover Dam or Niagara
>Falls, you are still a guilty ozone-killer - repent you
>sinner!
>
>If you love AL GORE, you will use carbon fibre and boycott all
>alumiunum products.

Re: Al Gore movie assignment.

Dear Paul,

You haven’t been paying attention have you? Maybe you should see "the movie" again and pay really close attention this time, perhaps take notes.

You are confusing two separate arguments here.

#1
It's argued that Ozone Depletion is caused by Chloro-fluoro-carbons (CFCs), used as coolants for commercial and home refrigeration units amongst other things.

#2
It's also argued that global warming/climate change comes from excess man-made carbon dioxide etc (Greenhouse gasses) eg auto exhausts, and coal fired power stations, not from hydro electricity plants.

So aluminium produced by "green-house friendly" hydro power stations would be just fine!

Grade D, please resubmit assignment in light of the above comments.

The Teacher.

>Obviously, aluminum requires tremendous amouts of electricity
>to produce, thus giving off greenhouse gas, destroying the
>ozone layer, and future contributing to man-made controllable
>GLOBAL WARMING.
>
>Even if your electricity comes from Hoover Dam or Niagara
>Falls, you are still a guilty ozone-killer - repent you
>sinner!
>
>If you love AL GORE, you will use carbon fibre and boycott all
>alumiunum products.

Do I then have to give up carbon fiber if I don't?

And global warming just took a turn for the worse. They are projecting the coldest February on record for our area. OK, so we had a few warmer months earlier. Sort of balances out, doesn't it?

And why do they call ozone a pollutant in California (everthing is a pollutant in California) and yet don't want us to deplete the ozone layer. Wouldn't pumping a bit more into the atmosphere help the situation? The smog should shield us from the sun's rays and cool the climate, right? Why are we talking about this? I thought we were building airplanes. It's the building season. Build.

Ho Ho Ho,
Global warming is a HOAX...and so is AlGore!!!

>Obviously, aluminum requires tremendous amouts of electricity
>to produce, thus giving off greenhouse gas, destroying the
>ozone layer, and future contributing to man-made controllable
>GLOBAL WARMING.
>
>Even if your electricity comes from Hoover Dam or Niagara
>Falls, you are still a guilty ozone-killer - repent you
>sinner!
>
>If you love AL GORE, you will use carbon fibre and boycott all
>alumiunum products.


Ron B.
F4Fguy

And have you any idea how much energy it takes to produce carbon fiber????????

Ron B.

A great description of how pushrods were made before CF and light alum tubes became available using 1/4 square balsa. I still have a 20 year old trainer with rods like that, never a problem.

What really matters is the section modulus of the shaft as that determines the compression flex of the rod. The higher the section modulus the more resistance to bending under compression load. Also known in engineering analysis as the "l/rho".

don Burke
Menifee, CA

yep the coefficient of expansion....approx. 12 millionths of an inch per inch per degree of temperature rise ..hope i spelled all the words right...so you must always fly in a temperature contolled environment 69 degrees farenhieght is optimal for the aluminium...otherwise your control rod will grow .. jim

LOL - You can buy good CF arrow shafts at almost any Sporting Goods store for $3 ea. Given the relative value of or time, who cares about the cost of the pushrods?

Dave Brown's F/G pushrods are $5 for 2 sets. Weight difference - 99% of will never notice or care; all that maters is positive control!

Just my opinion

>yep the coefficient of expansion....approx. 12 millionths of
>an inch per inch per degree of temperature rise ..hope i
>spelled all the words right...so you must always fly in a
>temperature contolled environment 69 degrees farenhieght is
>optimal for the aluminium...otherwise your control rod will
>grow .. :@ jim


Ron B.
F4Fguy

And the real world expansion difference is even less. The carbon itself has about 1/3 the expansion of the Al. The epoxy?(thermoset) binder has any where from 2/3- 1 1/3 the Al. the Carbon/epoxy will have an expansion coefficient somwhere between the two, depending on the carbon/ epoxy ratio.

As has been pointed out in another post above, the expansion of the fuselage could be almost as much, the same or greater depending on the construction and the length.

Ron B.

>BTW, any-one at KMAC want a CF arrow shaft? I can give away 3 or 4.



G'day Dave,

You may not know that KMAC are hosting the annual Hearns Trophy F2B Stunt Competition on Sunday February 25th starting at 10am.

Should be a great day so why not come down to the field to enjoy the spectacle of precision aerobatic competition and maybe ask around if anyone wants a CF arrow shaft? We're having a BBQ sausage sizzle lunch as well.

Maybe see you then...?

Cheers,

Peter O'Keeffe / Melbourne AU

>>BTW, any-one at KMAC want a CF arrow shaft? I can give
>away 3 or 4.
>
>
>
>G'day Dave,
>
>You may not know that KMAC are hosting the annual Hearns
>Trophy F2B Stunt Competition on Sunday February 25th
>starting at 10am.
>
>Should be a great day so why not come down to the field to
>enjoy the spectacle of precision aerobatic competition and
>maybe ask around if anyone wants a CF arrow shaft? We're
>having a BBQ sausage sizzle lunch as well.
>
>Maybe see you then...?
>
>Cheers,
>
>Peter
>O'Keeffe
>/ Melbourne AU


Got a busy day then but MAY be able to come down later, I would surely like to.... What time will it finish ? I know you will not know exactly...
Many thanks to all for info about Aluminium shafts.
Also the info about cutting CF arrows, I did know this ( my eldest Son worked with fibre-glass at one of his jobs for 2 or 3 years...)
But it still bears repeating... indeed the guy who gave me the arrows made sure I knew this.
For those who do not know.... Carbon Fibre is VERY thin.... bits can very easily get under your skin and fester.... not unknown for people to lose a finger etc....

>>You may not know that KMAC are hosting the annual Hearns Trophy F2B Stunt Competition on Sunday February 25th


>Got a busy day then but MAY be able to come down later, I would surely like to.... What time will it finish ?


The stunt competition may finish around 2 - 3pm depending on the number of entries.

Cheers,

Peter O'Keeffe

KMAC - Melbourne, Australia

good info here in this thread this

aluminum will work harden with bending and straightning this localized hardening will cause it to crack
may happen over looonnnggg term from vibration as well.
another good alloy for this(possibly best)is 6061 to t6--grain should run lenghtways

wrap carbon rods tightly with tape(straping tape best) and cut with cut off through tape---keeps it from fraying/splitting as bad and keeps up with dangerous(they are)loose fibers.

anyone tryed graphite?couldnt find carbon arrow shafts for last build and used these--kinda heavy--about like aluminum.

>anyone tryed graphite?couldnt find carbon arrow shafts for
>last build and used these--kinda heavy--about like aluminum.
>


Ron B.
F4Fguy

Graphite is carbon.

Ron B.

Well, carbon tied up in a carbon or graphite arrow isn't floating around as CO

I once visited a graphite mine. There is no dirtier job in the world. Maybe better today than in the 50's one hopes.

>Well, carbon tied up in a carbon or graphite arrow isn't
>floating around as CO2:-)
>
>I once visited a graphite mine. There is no dirtier job in
>the world. Maybe better today than in the 50's one hopes.


Ron B.
F4Fguy

Jim,

Don't try to write with a "graphite" pushrod.

The Carbon in either a "graphite" or "carbon" pushrod consists of fibers which are long lengths of single carbon crystals which are grown under controlled conditions and which don't occur in nature. It's the fact of they're being single crystals that give them their tremendous tensile strength and modulus of elasticity.

Ron B.

Dave, I cannot imagine any modern arrowshaft not strong enough for use as a control rod in a stunt ship!

Years ago, I was in an archery shop, and mentioned that I was looking for a source of arrowshafts for my model airplane. The guy brought out a couple dozen damaged arrowshafts of several varieties, a lifetime supply, which he gave me.

I always seem to pick the fiberglass ones, they work fine, don't splinter easily, last forever, have no perceptible flex in the application, etc. They can also be painted for a profile ship.

I see the fine CF ones, they seem an overkill to me. And I may be wrong, since I haven't weighed them for comparison, but my perception is that they are heavier than the fiberglass arrowshafts. And they cost money. (But they do have nice plastic fittings - which HAVE to be pinned and well glued! I've never had a problem with a wooden dowel with a flat sanded on it for the plug, and it glues well.)

The only improvement I might consider, although unnecessary, would be to purchase some of the smaller diameter ones used for modern kites and such..

My opinion, but in CL Stunt we frequently indulge in overkill. JMHO. I do it with homemade Magic Geometry controls. Others do it with CF arrowshafts that are entirety TOO strong..

[photo not recovered: 22137.jpg]

"God bless us, every one." -Tiny Tim

>Dave, I cannot imagine any modern arrowshaft not strong
>enough for use as a control rod in a stunt ship!
>
>Years ago, I was in an archery shop, and mentioned that I was
>looking for a source of arrowshafts for my model airplane. The
>guy brought out a couple dozen damaged arrowshafts of several
>varieties, a lifetime supply, which he gave me.
>
>I always seem to pick the fiberglass ones, they work fine,
>don't splinter easily, last forever, have no perceptible flex
>in the application, etc. They can also be painted for a
>profile ship.
>
>I see the fine CF ones, they seem an overkill to me. And I may
>be wrong, since I haven't weighed them for comparison, but my
>perception is that they are heavier than the fiberglass
>arrowshafts. And they cost money. ;) (But they do have nice
>plastic fittings - which HAVE to be pinned and well glued!
>I've never had a problem with a wooden dowel with a flat
>sanded on it for the plug, and it glues well.)
>
>The only improvement I might consider, although unnecessary,
>would be to purchase some of the smaller diameter ones used
>for modern kites and such..
>
>My opinion, but in CL Stunt we frequently indulge in overkill.
>JMHO. I do it with homemade Magic Geometry controls. Others do
>it with CF arrowshafts that are entirety TOO strong.. ;)
>
>[photo not recovered: 22137.jpg]
>
>"God bless us, every one." -Tiny Tim


Ron B.
F4Fguy

AMEN!

All too often "strength" and stiffness are confused. Graphite/carbon pushrods are strong. They're also stiff,but stiffness is as much a function of section modulus as of the material's modulus of elasticity. A larger diameter thinner walled tube of a weaker material may be as stiff as the carbon in this application and also be lighter.

Ron B.