substitutes for sitka spruce
Dean Dayton
I am in the process of building a Pietenpol AirCamper.
I have read several articles on the use of Douglas Fir instead of Sitka
Spruce. The articles always state that I should be able to find Douglas
Fir at a local lumber yard. Well, I went looking and what I found was
that the lumber yard classified the lumber as Hem-Fir or
Spruce-Fir-Pine. How can I tell what kind of wood it really is?
From what I saw, I think that I could hand select lumber with
appropriate grain, etc. But I am not sure exactly what the lumber is.
Are there any easy ways to tell the difference? Can someone recommend a
source of Douglas Fir near Columbus, OH?
======================================================================
Dean Dayton
de...@aiinet.com
David Stadt
Dean:
One thing to keep in mind is the added weight of Douglas Fir. Just
checked a reference manual and it shows Sitka Spruce at 28 Lbs per
cubic foot and Douglas Fir at 33 Lbs. Also don't think you will find
what you need at the local lumber yard. Might find Doug Fir but it
will not be clear or of the quality needed for aircraft work. Might
just want to bite the bullet and order the Sitka Spruce. It takes
some pretty sophisticated lab equipment to determine wood type once it
is turned into lumber. In addition there are a jillion types of fir so
the stuff marked hem-fir or spruce-fir-pine is a crap shoot.
Dave S.
Pinesay
You said: >>I am in the process of building a Pietenpol AirCamper.
I have read several articles on the use of Douglas Fir instead of Sitka
Spruce. The articles always state that I should be able to find Douglas
Fir at a local lumber yard. Well, I went looking and what I found was
that the lumber yard classified the lumber as Hem-Fir or
Spruce-Fir-Pine. How can I tell what kind of wood it really is?
From what I saw, I think that I could hand select lumber with
appropriate grain, etc. But I am not sure exactly what the lumber is.<<
--------------------------------------------------------------------------
-------------------------------------------
For God's Sake, buy genuine sitka spruce!!!!!!!!! It is for most
excellent reason the designer specified this kind of wood!!!!!!! Not only
is it light in weight, it is famous for resisting splitting/breaking, and
for many years has been the wood most specified for construction of wood
aircraft.
Please do take the time and trouble to get the proper wood via known and
reputable aviation supply houses. Your life is valuable!!!!!!! And,
don't forget, your airplane project has to be documented and approved by a
FAA inspector before it will be allowed to fly. Do get in touch with your
nearest EAA club!!!!!!!!!
Pinesay
Daniel Grunloh
In article <331329...@aiinet.com>, Dean Dayton <de...@aiinet.com> wrote:
>I am in the process of building a Pietenpol AirCamper.
>
>I have read several articles on the use of Douglas Fir instead of Sitka
>Spruce. The articles always state that I should be able to find Douglas
>Fir at a local lumber yard. Well, I went looking and what I found was
>that the lumber yard classified the lumber as Hem-Fir or
>Spruce-Fir-Pine. How can I tell what kind of wood it really is?
These types are not Doug Fir as they call it in the lumber trade.
There are many types of fir and Douglas Fir isn't even a true fir.
But it is, (I believe) always distinguished from the mixed species.
Doug Fir is sometimes specified in important structural uses.
You might find it sold as 2-12 planks for making stairs, or as long
2x4's intended for use as scaffolding lumber. Beware of Fir sold
for fascia and trim as 3/4 inch lumber as this may be red or white
fir which is notably softer. Once you find Doug Fir you will know
it because its hard, heavy, and very fine grained. Never use any
portion of a plank which has pitch pockets or signs of excess pitch
oozing out the ends. Use of Doug Fir in thick sections should be
minimized because of the hazard of pitch pockets. Selecting only light
colored non-sticky lumber will reduce the threat greatly.
To find Doug Fir, widen your search considerably by using the phone. Any
lumber yard should know right away if they have any Doug Fir.
Due to the shortage and poor quality of Spruce these days, more and
more designers are looking at Doug Fir which is approx. 10% stronger
but 10-15 % heavier. Some well established ultralights use Pine.
Doug Fir can always be substituted for Pine or Spruce but not the
other way around. Several hundred Sky Pup builders have had to
search out and find Doug Fir for their spars.
I once ordered some Sitka spruce (not spar grade) and found the grain
density and slope to be MUCH poorer than any pine or doug fir I had found.
I wouldn't think of using that crap in my airplane. [flame bait]
-------------------------
--Daniel Grunloh (gru...@uiuc.edu)
--University of Illinois at Champaign-Urbana
--http://www.staff.uiuc.edu/~grunloh
bal...@aol.com
> The articles always state that I should be able to find Douglas
>Fir at a local lumber yard.
Sorry, DOUGLAS FIR is a great substitute for Sitka Spruce but you will not find the stuff you need locally. I go to a place in Wisconsin (from Cincinnati) for my Fir and always find what I need. It's about 1/3 the cost of spruce but you must be capable of grading it yourself and you'll need a moisture meter.
bal...@aol.com
>For God's Sake, buy genuine sitka spruce!!!!!!!!! It is for most
>excellent reason the designer specified this kind of wood!!!!!!! Not only
>is it light in weight, it is famous for resisting splitting/breaking, and
>for many years has been the wood most specified for construction of wood
>aircraft.
Thats kind of a narrow minded post don't you think? Especially as it relates to EXPERIMENTAL aircraft construction. All types of wood have been used in aircraft over the years including CERTIFIED. Spruce, certain cedar, ash, hemlock, Douglas Fir, Northern White Pine, etc. all have a place in these aircraft. I don't suggest however that you experiment with your life. Follow the FAA published specs and inspections on selecting wood for aircraft use.
John McPhail
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Look at strength specs for Doug Fir.....
Woah, guess what !?!?!, stronger, just ever so slightly heavier
though....
(I believe less than 2% heavier, from memory...)
And in certain parts of Montana and Idaho, you can get small custom
mills
to custom lumber.... there's a few local that do it....
Have you seen what CERTIFIED really means.... not certified by the FAA.
in fact if you follow the FAA's guidelines on lumber selection, and
grain and grain size and all that, guess what, you can CERTIFY it
yourself,
if you have doubts, have two pieces cut from same larger board,
STRESS TEST ONE (i.e. FAA wing loading test for certified or
experimental aircraft.....let's see 3g's = weight of airplane x3.... put
sand bags on the spar...
....once one passes the test (IT MAY NOT !), use the other one...
I don't know....I have doug fir extension ladders to 38 feet, you can be
killed from a fall of as little as 3ft. (reference OSHA handbook), now I
guess, I'm experimenting with my life everytime I get up this ladder,
built a hangar with it this summer....I'M STILL ALIVE - a miracle... or
just a good ladder, built out of hand-selected doug fir....
Sorry, both grandfathers were carpenters.....
I disagree with the above post..
John McPhail
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<HTML><BODY>
<DT> Lba...@aol.com wrote:<BR>
> <BR>
> In article <19970226151...@ladder02.news.aol.com>,
pin...@aol.com (Pinesay) writes:<BR>
> <BR>
> >For God's Sake, buy genuine sitka spruce!!!!!!!!! It is
for most<BR>
> >excellent reason the designer specified this kind of wood!!!!!!!
Not only<BR>
> >is it light in weight, it is famous for resisting splitting/breaking,
and<BR>
> >for many years has been the wood most specified for construction
of wood<BR>
> >aircraft.<BR>
> <BR>
>
Thats kind of a narrow minded post don't you think? Especially as it relates
to EXPERIMENTAL aircraft construction. All types of wood have been used
in aircraft over the years including CERTIFIED. Spruce, certain cedar,
ash, hemlock, Douglas Fir, Northern White Pine, etc. all have a place in
these aircraft. I don't suggest however that you experiment with your life.
Follow the FAA published specs and inspections on selecting wood for aircraft
use.<BR>
<BR></DT>
<DT> </DT>
<DT>Look at strength specs for Doug Fir.....</DT>
<DT> </DT>
<DT>Woah, guess what !?!?!, stronger, just ever so slightly heavier though....</DT>
<DT>(I believe less than 2% heavier, from memory...)</DT>
<DT> </DT>
<DT>And in certain parts of Montana and Idaho, you can get small custom
mills</DT>
<DT>to custom lumber.... there's a few local that do it....</DT>
<DT> </DT>
<DT>Have you seen what CERTIFIED really means.... not certified by the
FAA.</DT>
<DT>in fact if you follow the FAA's guidelines on lumber selection, and
grain and grain size and all that, guess what, you can CERTIFY it yourself,</DT>
<DT>if you have doubts, have two pieces cut from same larger board,</DT>
<DT>STRESS TEST ONE (i.e. FAA wing loading test for certified or experimental
aircraft.....let's see 3g's = weight of airplane x3.... put sand bags on
the spar...</DT>
<DT>....once one passes the test (IT MAY NOT !), use the other one...</DT>
<DT> </DT>
<DT>I don't know....I have doug fir extension ladders to 38 feet, you can
be killed from a fall of as little as 3ft. (reference OSHA handbook), now
I guess, I'm experimenting with my life everytime I get up this ladder,
built a hangar with it this summer....I'M STILL ALIVE - a miracle... or
just a good ladder, built out of hand-selected doug fir....</DT>
<DT> </DT>
<DT>Sorry, both grandfathers were carpenters.....</DT>
<DT>I disagree with the above post..</DT>
<DT> </DT>
<DT>John McPhail</DT>
<DT> </DT>
<DT>jmcp...@bmt.net</DT>
<DT> </DT>
</BODY>
</HTML>
------------561925308C44--
John R. Johnson
On 26 Feb 1997, Pinesay wrote:
> You said: >>I am in the process of building a Pietenpol AirCamper.
>
> I have read several articles on the use of Douglas Fir instead of Sitka
> Spruce. The articles always state that I should be able to find Douglas
> Fir at a local lumber yard. Well, I went looking and what I found was
> that the lumber yard classified the lumber as Hem-Fir or
> Spruce-Fir-Pine. How can I tell what kind of wood it really is?
>
> From what I saw, I think that I could hand select lumber with
> appropriate grain, etc. But I am not sure exactly what the lumber is.<<
> --------------------------------------------------------------------------
> -------------------------------------------
> For God's Sake, buy genuine sitka spruce!!!!!!!!! It is for most
> excellent reason the designer specified this kind of wood!!!!!!! Not only
> is it light in weight, it is famous for resisting splitting/breaking, and
> for many years has been the wood most specified for construction of wood
> aircraft.
> Please do take the time and trouble to get the proper wood via known and
> reputable aviation supply houses. Your life is valuable!!!!!!! And,
> don't forget, your airplane project has to be documented and approved by a
> FAA inspector before it will be allowed to fly. Do get in touch with your
> nearest EAA club!!!!!!!!!
>
> Pinesay
Of course the designer of the Pietenpol Air Camper was Bernie Pietenpol.
Bernie used Douglas Fir from his local lumberyard for his later copies
of his Air Camper design because of the difficulty of obtaining suitable
spruce. It is merely a matter of grading the lumber you use. About half
of the spruce sold by the "known and reputable aviation supply houses" is
marginal at best and the stock must be selected for quality. Bernie used
to use laminations so he could get the sizes he needed from the poor
quality spruce available. Proper joints in a laminated member are ok is
the joinery is done correctly. A properly prepared and glued scarf joint
is as strong or stronger than the original wood. Make sure you get a copy
of the grading requirements for aircraft wood. There is no such thing as
"CERTIFIED" wood. Only wood that has been selected according to the
aircraft wood selection specification. Aircraft wood is NOT restricted
to Sitka Spruce. Many of the fine wooden aircraft built commercially in
this country used many other woods besides spruce, including Douglas Fir,
Cedar, Ash, Hickory, Poplar, Maple, Oak, Mahogany, Birch, and Pine.
Before you substitute woods you should have some information about the
relative strengths and densities. For example, you could substitute White
Oak for Spruce, but the difference in weight might cause you serious
problems. The strength would be alright. Spruce is NOT particularly
strong. It is merely strong for it weight! Port Orford Cedar is real
close to spruce, as is Douglas Fir. Spruce is quite nice to work.
John
Steve Eldredge
Pinesay wrote:
Pinesay
Oh Brother. Douglas fir is quite acceptable. You will find it in
FAR43 as an acceptable substitute for spruce. I have built an
Aircamper. I built it out of aircraft grade Doug fir without any
problems. It is a little heavier, but it is stronger and about 1/5th
the price of spruce. I found all my wood locally, although it took some
trench work to get the stuff that was good enough. You need to find a
wood whosaler or a mill. Join the Buckeye Pietenpol Association. It
has an excellent newsletter. Check out their web site by Grant McLaren.
http://users.aol.com:80/bpanews/www.html
Congratulations on your choice of a Piet. It is one of the most proven
designs and one of the oldest homebuilts around. I'll be flying mine
this summer for about $3500 complete after 2.5 years of building
Steve Eldredge
John R. Johnson
I have found excellent Douglas Fir by purchasing 5/4 stairtread stock.
You do have to get permission from the lumberyard to do a little selection,
since only a percentage of the wood available has close enough grain and
straight enough to meet the aircraft wood specification. I have never had
a problem with a lumberyard when I told them it was for my airplane. They
often helped me dig through their stack of lumber.
John
On Tue, 25 Feb 1997, David Stadt wrote:
> Dean:
>
> One thing to keep in mind is the added weight of Douglas Fir. Just
> checked a reference manual and it shows Sitka Spruce at 28 Lbs per
> cubic foot and Douglas Fir at 33 Lbs. Also don't think you will find
> what you need at the local lumber yard. Might find Doug Fir but it
> will not be clear or of the quality needed for aircraft work. Might
> just want to bite the bullet and order the Sitka Spruce. It takes
> some pretty sophisticated lab equipment to determine wood type once it
> is turned into lumber. In addition there are a jillion types of fir so
> the stuff marked hem-fir or spruce-fir-pine is a crap shoot.
>
> Dave S.
>
> Dean Dayton wrote:
> >
> > I am in the process of building a Pietenpol AirCamper.
> >
> > I have read several articles on the use of Douglas Fir instead of Sitka
> > Spruce. The articles always state that I should be able to find Douglas
> > Fir at a local lumber yard. Well, I went looking and what I found was
> > that the lumber yard classified the lumber as Hem-Fir or
> > Spruce-Fir-Pine. How can I tell what kind of wood it really is?
> >
> > From what I saw, I think that I could hand select lumber with
> > appropriate grain, etc. But I am not sure exactly what the lumber is.
> >
David Munday
>
> I have read several articles on the use of Douglas Fir instead of Sitka
> Spruce. The articles always state that I should be able to find Douglas
> -------------------------------------------
> For God's Sake, buy genuine sitka spruce!!!!!!!!! It is for most
> excellent reason the designer specified this kind of wood!!!!!!! Not only
> is it light in weight, it is famous for resisting splitting/breaking, and
> for many years has been the wood most specified for construction of wood
> aircraft.
> Please do take the time and trouble to get the proper wood via known and
> reputable aviation supply houses. Your life is valuable!!!!!!! And,
> don't forget, your airplane project has to be documented and approved by a
> FAA inspector before it will be allowed to fly. Do get in touch with your
> nearest EAA club!!!!!!!!!
Well, I'm breaking my own rule here by speaking twice on the same subject,
BUT, this is damned silly, and alarmist.
There's nothing special about the spruce that comes from ACS&S or Wicks or some
such place. There is no such thing as the kind of controlled production that
you have with man made materials. You can't counterfeit the stuff and you don't
need a big lab to analyse it.
The stuff grows, somebody cuts it down and saws it into boards, and somebody
selects that part that is aircraft grade. That last somebody can be you.
There's a military spec written for the geniuses in purchasing. Read
the spec, follow the spec, build the plane.
--
Dave Munday - mund...@miavx1.acs.muohio.edu
Web Page: http://www.nku.edu/~munday
PP-ASEL - Tandem Flybaby Builder - EAA-284 (Waynesville, OH)
Say whatever it is you have to say; Say it clearly; Say it ONCE.
David Munday
In article <331397...@lnd.com>, David Stadt <dhs...@lnd.com> writes:
> Dean:
>
> One thing to keep in mind is the added weight of Douglas Fir. Just
> checked a reference manual and it shows Sitka Spruce at 28 Lbs per
> cubic foot and Douglas Fir at 33 Lbs. Also don't think you will find
> what you need at the local lumber yard. Might find Doug Fir but it
> will not be clear or of the quality needed for aircraft work. Might
> just want to bite the bullet and order the Sitka Spruce. It takes
> some pretty sophisticated lab equipment to determine wood type once it
> is turned into lumber. In addition there are a jillion types of fir so
> the stuff marked hem-fir or spruce-fir-pine is a crap shoot.
Well, i did an analysis of the weight penalty for building a GP-4 out
of fir instead of spruce. My analysis assumed use of the same dimension
lumber as with spruce. You can safely reduce the cross sectional area of
peices if you use fir because it's stronger, but I was looking for an upper
bound, and staying with the dame dimensions would yeild a stronger plane.
My analysis reveals that the weight of the woodpile you start with goes from
182.28 lbs to between 196.16 and 218.97 lbs (fir varies more with weight than
spruce) The penalty for the WOODPILE is at most 36.50 lbs and a lot of that
ends up in the scrap pile so it is a generously liberal upper bound. This
represents 2.9% of empty weight or 4.9% of usefull load.
Now, this weight penalty can be much reduced. You can select mountain fir
rather than coastal (same species, different conditions, different density),
this brings the weight penalty down to 13.69 lbs (1.1% of empty weight, and
1.9% of usefull load, and that's still the weight of the woodpile, not the
weight of the wood that actually ends up in the plane) You can reduce the
cross sectional area, thereby the volume and weight of wood. I don't have the
numbers handy, but if you dimention the stuff right (dimentioned for same
strength as spruce) you end up heavier by 1-2% of the total wood weight.
On the other hand, D-Fir is more splintery, and doesn't machine as well, but it
costs one third as much.
Those who say you should use Spruce or you endanger yourself are plain silly.
You'll save money, you'll likely add weight, or work, or both, and you have to
learn to grade the boards yourself, but it ain't rocket science. You get the
EAA wood book, read the articles on Mil Spec wood, and you check the stuff
against the spec. You don't need any fancy equipment. (A moisture meeter
helps, but you can determine moisture content with a scale and a kitchen oven,
the EAA wood book tells you how)
Like any other engineering problem it comes down to weighing advantages
and disadvantages. For availability fr wins, for cost fir wins BIG, for weight
spruce wins, it doesn't win by much if you design for it to begin with or if
you re-engineer to same strength.
Now, I'll leave you because I've got to go glue up some Fir for my landing
gear.
S. Rennacker
Good post! Regarding D-fir's splinteryness, that is more of a problem if
you are using nails in very dry fir. If you are drilling and
screwing/bolting/gluing it's not so much of a problem.
Of course, individual pieces can vary quite a bit, as with any wood. The
strongest are clear, straight-grained with the grain lines close
together. You can pick over what is at your local lumber yard in the
pacific northwest (including Home Depot). If moisture content is a
concern, "kiln-dried" clear fir is available, but it has become very
expensive. Hand picking construction grade stock for dryness (you can
roughly tell by the heft) and grade would work fine.
Actually, the very best fir would likely be recycled from some demolished
old building. Just for fun to might support a 3' piece of, say, 1x3 of
vaious kinds between two points and compare how much weight they will
support before breaking...
David Munday (mund...@miavx1.muohio.edu)
wrote:
--
S. Rennacker (s...@crl.com) Berkeley, California
-- Seconds for some after firsts for all. --
J Mapes
> Dean Dayton wrote
> I am in the process of building a Pietenpol AirCamper.
> I have read several articles on the use of Douglas Fir instead of Sitka
> Spruce. The articles always state that I should be able to find Douglas
> Fir at a local lumber yard. Well, I went looking and what I found was
> that the lumber yard classified the lumber as Hem-Fir or
> Spruce-Fir-Pine. How can I tell what kind of wood it really is?
> From what I saw, I think that I could hand select lumber with
> appropriate grain, etc. But I am not sure exactly what the lumber is.
>
> Are there any easy ways to tell the difference? Can someone recommend a
> source of Douglas Fir near Columbus, OH?
I built a HI-MAX ultralight from Douglass Fir purchased at a local lumber
yard. It came in the form of 1 x 4 tongue and groove porch flooring and it
worked GREAT. It comes in lengths up to 16 feet and as an added advantage
a lot of it is quarter sawn which is what you are looking for. In general
what you are looking for are boards with about 12 to 15 growth rings per
inch quarter sawn with the rings at less than 30 deg incline looking at the
end of the board, straight up and down being the best lllllllllllllll .
The other things you need to watchout for are grain runout (running off the
edge of the board looking at the top or wide face) knots, pitch pockets,
and one that is a bit harder to detect something called compression
fractures. Compression fractures are caused when a tree is cut down and
lands on uneven ground another tree or whatever and the fibers in the are
torn and make that particular spot in the tree weak. Hey douglass fir
worked OK for me, but the plane did weigh just a tad over the 256# ul
weight limit but I think that had more to do with using Birch door skins
instead of Luan. I figure the Birch is a bit heavier but a lot stronger.
The only problem was filling in those holes where the doorknob and deadbolt
were supposed to go. ;-) .. have fun building .... if ya wanta see the hi
max it's on the ultralight home page here's the url
http://www.cs.fredonia.edu/~stei0302/WWW/ULTRA/q-t_t.html
Ya also might want to check this out
Buckeye Pietenpol Association - The BPA is THE place to obtain the most
accurate, current and interesting information about Pietenpol airplanes.
http://users.aol.com/BPANews/www.html - size 22K - 20-Feb-97
Best wishes from Joe Mapes the FLY4FUN guy
Ed Sullivan
I have worked with both spruce and Doug Fir. I would have to say that
spruce is a much nicer material to work with and unless you plan on flying
for free, the cost of Aircraft grade spruce is still plenty reasonable. The
plywood in a wooden design is usually the expensive item.
John McPhail <jmcp...@bmt.net> wrote in article <3314BA...@bmt.net>...