Can we go back to making planes out of wood again now?
Moderator
Thread Starter
Can we go back to making planes out of wood again now?
It occurred to me this morning that the main reason that they stopped making planes out of wood all those years ago, was not that it was not a good material for planes, but indeed the ever increasing regulatory oversight was creating a need for so much more paperwork. They simply need the trees for the paper, and there were not enough left to build airplanes. (If we had to use aluminum sheet for our reports and records, the office staff could not carry as many around from office to office for endless review, and aluminum cuts would be much more serious!)
But now, we use computers! Virtual paper! We still have rediculous amounts of documentation to do to fly, but we don't necessarilty have to print all of it out anymore.
So would that mean that if the regulatory side of our industry is conservation minded, and diligent about not printing out all of our "paperwork", we can go back to charming, economical and eco friendly wood as a construction material for our aircraft?
But now, we use computers! Virtual paper! We still have rediculous amounts of documentation to do to fly, but we don't necessarilty have to print all of it out anymore.
So would that mean that if the regulatory side of our industry is conservation minded, and diligent about not printing out all of our "paperwork", we can go back to charming, economical and eco friendly wood as a construction material for our aircraft?
Join Date: Oct 2005
Location: USA
Posts: 3,218
Likes: 0
Received 0 Likes
on
0 Posts
Wood is a great building material for airplanes. It doesn't fatigue, it's easy to work, and you glue it together. Fabric is a lot of fun, too. Especially in a closed hangar...
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
“stopped making planes out of wood all those years ago”
There are many current designs such as the Pioneer 300, which use a lot of wood. A combination of Wood and Carbon Fiber is quite common in VLA / LSA and probably ELA1 when it arrives. I think the Robin range is also going back into production.
Rod1
There are many current designs such as the Pioneer 300, which use a lot of wood. A combination of Wood and Carbon Fiber is quite common in VLA / LSA and probably ELA1 when it arrives. I think the Robin range is also going back into production.
Rod1
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Realistically against modern materials wood doesnt stack up (excuse the pun)
We only have to look at modern formula 1 technology to realise that modern composites give the lightest and strongest structures.
Proof of the pudding is in the eating and if wood was so good it would be used in formula 1 contruction.
Having said that I am sure for the homebuilder it is an excellent material to use.
I used to be a rower and still do a little now we had a true craftsmen and one of the best racing boat builders around. He constructed in wood. It was time consuming and very detailed. The boats were works of pure art and there lies the answer to wood. But today racing 8s and skulls are made in very light strong composites as wood cannot compete in cost or on the rivers in races.
Pace
We only have to look at modern formula 1 technology to realise that modern composites give the lightest and strongest structures.
Proof of the pudding is in the eating and if wood was so good it would be used in formula 1 contruction.
Having said that I am sure for the homebuilder it is an excellent material to use.
I used to be a rower and still do a little now we had a true craftsmen and one of the best racing boat builders around. He constructed in wood. It was time consuming and very detailed. The boats were works of pure art and there lies the answer to wood. But today racing 8s and skulls are made in very light strong composites as wood cannot compete in cost or on the rivers in races.
Pace
Last edited by Pace; 7th Jan 2011 at 15:48.
Moderator
Thread Starter
Hmmm, it would appear that my attempt at humour was a bit too subtle, in the forum of people who actually would build a plane.....
Oh well... Onward with the discussion of the merits of wood as an aircraft building material...
Yes, the Bellanca Viking is a magnificent example of how wood can be used to make a plane. I know there are many others too....
Oh well... Onward with the discussion of the merits of wood as an aircraft building material...
Yes, the Bellanca Viking is a magnificent example of how wood can be used to make a plane. I know there are many others too....
Join Date: Sep 2006
Location: Los Angeles, USA
Age: 52
Posts: 1,631
Likes: 0
Received 0 Likes
on
0 Posts
This is a subject close to my heart. I could not agree more. Wood is criminally overlooked in these carbon crazy times.
Like Guppy said - no fatigue and no time limits. In fact, within the rotor world the Bell 47 could be supplied with both wooden blades and aluminium spar blades. Guess which one has a time limit? The wooden ones are on inspection only.
The Kaman K-Max heavy lifting helicopter have glass fibre covered wood core blades to this day. The Vietnam veteran Kaman HH-43 Huskie (nicknamed Pedro) also had this construction. We're talking heavy lifters here and real work horses, not some flimsy recreational helicopter.
Carbon fibre is the in material at the moment and any manufacturer throwing those words around will try to appeal to peoples fancy with this material to seem cutting edge. What most people fail to realize is that FAA certification for carbon fibre epoxy construction demands a 2x safety factor in construction (because of the unknown properties and the differences in the hand lay up and curing), whereas alu and wood only demands 1,5x safety factor. This pretty much always negates any weight saving and carbon fibre aircraft are normally as heavy or heavier than an equivalent wood or alu aircraft. Not only that, carbon fibre epoxy construction is very expensive, environmentally unfriendly and oil dependant.
But wood is a composite as well and could very easily be formed into exactly the same complex shapes and be as strong. In fact, many woods are stronger than metal. People refuse to believe that birch is 1.7 times stronger than aluminium in specific strength (strength per weight). For some reason people think of metals as stronger, when they're many times not.
Just remember the old 70's fruit bowls and how lightweight and strong they were. We used to bang, drum, jump, drive over these with our trikes and generally abuse them as kids, yet they didn't budge in shape:
Or how many complex shapes you can achieve with modern epoxy plywood construction:
But building complex shapes with wood is nothing new. It was done over 80 years ago in the still used strip wood fashion. Just like many cedar strip kayaks are constructed today (and are almost always lighter than carbon fibre kayaks, but this people also refuse to believe in). Take a look at these images of an old Deperdussin racer for instance:
Wood fits well with modern epoxy based construction. And the drawbacks that used to be there are no longer an issue, like dry rot and impact tolerance. It would be environmentally friendly, sustainable, cheaper, as strong, as production friendly and as good to do modern aircraft this way. It's just that it's not cool with wood. That's the problem.
I hope this changes.
Like Guppy said - no fatigue and no time limits. In fact, within the rotor world the Bell 47 could be supplied with both wooden blades and aluminium spar blades. Guess which one has a time limit? The wooden ones are on inspection only.
The Kaman K-Max heavy lifting helicopter have glass fibre covered wood core blades to this day. The Vietnam veteran Kaman HH-43 Huskie (nicknamed Pedro) also had this construction. We're talking heavy lifters here and real work horses, not some flimsy recreational helicopter.
Carbon fibre is the in material at the moment and any manufacturer throwing those words around will try to appeal to peoples fancy with this material to seem cutting edge. What most people fail to realize is that FAA certification for carbon fibre epoxy construction demands a 2x safety factor in construction (because of the unknown properties and the differences in the hand lay up and curing), whereas alu and wood only demands 1,5x safety factor. This pretty much always negates any weight saving and carbon fibre aircraft are normally as heavy or heavier than an equivalent wood or alu aircraft. Not only that, carbon fibre epoxy construction is very expensive, environmentally unfriendly and oil dependant.
But wood is a composite as well and could very easily be formed into exactly the same complex shapes and be as strong. In fact, many woods are stronger than metal. People refuse to believe that birch is 1.7 times stronger than aluminium in specific strength (strength per weight). For some reason people think of metals as stronger, when they're many times not.
Just remember the old 70's fruit bowls and how lightweight and strong they were. We used to bang, drum, jump, drive over these with our trikes and generally abuse them as kids, yet they didn't budge in shape:
Or how many complex shapes you can achieve with modern epoxy plywood construction:
But building complex shapes with wood is nothing new. It was done over 80 years ago in the still used strip wood fashion. Just like many cedar strip kayaks are constructed today (and are almost always lighter than carbon fibre kayaks, but this people also refuse to believe in). Take a look at these images of an old Deperdussin racer for instance:
Wood fits well with modern epoxy based construction. And the drawbacks that used to be there are no longer an issue, like dry rot and impact tolerance. It would be environmentally friendly, sustainable, cheaper, as strong, as production friendly and as good to do modern aircraft this way. It's just that it's not cool with wood. That's the problem.
I hope this changes.
Last edited by AdamFrisch; 7th Jan 2011 at 16:36.
Wood is so old fashioned. New is always better, in fact a friend of mine, who prides himself on being an early adopter of new technology, is building his airplane out of a "naturally optimized, linearly organized cellulose composite".
Join Date: Sep 2006
Location: Los Angeles, USA
Age: 52
Posts: 1,631
Likes: 0
Received 0 Likes
on
0 Posts
Pace.
Carbon fibre has zero compression strength. You're relying on the epoxy resin to take that load. And that's an inefficient and heavy load bearer. The really light structures require very little epoxy resin or they get heavy quick. This is why S-glass gets so heavy - because the fibre or weave has to soak up so much resin to get stiff. The only reason you can build lighter structures for F1 is that you don't have to adhere to certification standards and you can form complex shapes easier. The minute you have to contend with the 2x safety factor for certification, carbon fibre is almost never lighter than traditional construction methods.
Carbon fibre has zero compression strength. You're relying on the epoxy resin to take that load. And that's an inefficient and heavy load bearer. The really light structures require very little epoxy resin or they get heavy quick. This is why S-glass gets so heavy - because the fibre or weave has to soak up so much resin to get stiff. The only reason you can build lighter structures for F1 is that you don't have to adhere to certification standards and you can form complex shapes easier. The minute you have to contend with the 2x safety factor for certification, carbon fibre is almost never lighter than traditional construction methods.
Last edited by AdamFrisch; 7th Jan 2011 at 16:37.
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Adam
I am not an aircraft builder ( Wood never have the patience or commitment
I was a Car racer and a rower.
I do agree that composite aircraft while pretty in shape lack the character that wood aircraft have and as a material to work with it must be very satisfying.
But there must be reasons why would is not used much by manufacturers today? probably that once the initial moulds are made its easier to mass produce in composites?
As for 2Xs is that because like restricted new engines they have to survive the test of time before the life is extended or the 2Xs is reduced or is it because there is an inherant weakness in composites which requires 2Xs?
Formula I cars take incredible pounding and strain and survive incredible crashes so ???
Maybe more to do with nostalgia?
Pace
I am not an aircraft builder ( Wood never have the patience or commitment
I was a Car racer and a rower.
I do agree that composite aircraft while pretty in shape lack the character that wood aircraft have and as a material to work with it must be very satisfying.
But there must be reasons why would is not used much by manufacturers today? probably that once the initial moulds are made its easier to mass produce in composites?
As for 2Xs is that because like restricted new engines they have to survive the test of time before the life is extended or the 2Xs is reduced or is it because there is an inherant weakness in composites which requires 2Xs?
Formula I cars take incredible pounding and strain and survive incredible crashes so ???
Maybe more to do with nostalgia?
Pace
Wood is a superb material for aeroplanes - how else did the Mosquito do so well, and for that matter the Minimax?
There are however some problems that need to be overcome, that have always been a problem.
(1) There are many many sorts of trees in the world, and each types wood has subtly different engineering properties. So, either you need an incredible amount of engineering data, and to some extent to keep generating new data with different samples - or you restrict yourself to a few very expensive woods.
(2) The manufacturing is very hard to automate.
(3) People with the right skill-sets are increasingly rare.
(1) and (2) are both solveable, but it'll always remain fairly labour intensive. However, the fact is that none of these problems exist for aluminium alloys, nor even to a fair extent for modern composites - and they do add cost.
G
There are however some problems that need to be overcome, that have always been a problem.
(1) There are many many sorts of trees in the world, and each types wood has subtly different engineering properties. So, either you need an incredible amount of engineering data, and to some extent to keep generating new data with different samples - or you restrict yourself to a few very expensive woods.
(2) The manufacturing is very hard to automate.
(3) People with the right skill-sets are increasingly rare.
(1) and (2) are both solveable, but it'll always remain fairly labour intensive. However, the fact is that none of these problems exist for aluminium alloys, nor even to a fair extent for modern composites - and they do add cost.
G
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Ghengis
Hence maybe why wood is popular with the home builder who is building one aircraft only as the Labour/time is probably pretty much the same between wood/composites and metal.
One of my favourites was the Falco.
Collecting uniform wood must also be difficult as nothing in nature is that uniform? knots, different fibre compressions?
I really dont know what I am talking about
Pace
Hence maybe why wood is popular with the home builder who is building one aircraft only as the Labour/time is probably pretty much the same between wood/composites and metal.
One of my favourites was the Falco.
Collecting uniform wood must also be difficult as nothing in nature is that uniform? knots, different fibre compressions?
I really dont know what I am talking about
Pace
Join Date: Sep 2006
Location: Los Angeles, USA
Age: 52
Posts: 1,631
Likes: 0
Received 0 Likes
on
0 Posts
Pace - yes, carbon fibre and especially Kevlar have better impact resistance. This is why whitewater canoes are almost never wood or aluminium. But impact resistance is less important for aircraft.
IO - this is true for old aircraft, but certainly not for new construction of wood composites. Just like canoes and other modern wood epoxy boats, the outer shell is covered in epoxy/glass. This makes it 100% water resistant. In fact, this is how they conserve many old wooend ships today.
Wood quality is important if you build in traditional ways. But less so when you're using wood as a compound material in epoxy construction. Then you can form very thin layers of ply of slightly various quality and still get a stiff structure.
Ask yourselves - why is every skateboard made out of plywood and not carbon fibre or aluminium?
IO - this is true for old aircraft, but certainly not for new construction of wood composites. Just like canoes and other modern wood epoxy boats, the outer shell is covered in epoxy/glass. This makes it 100% water resistant. In fact, this is how they conserve many old wooend ships today.
Wood quality is important if you build in traditional ways. But less so when you're using wood as a compound material in epoxy construction. Then you can form very thin layers of ply of slightly various quality and still get a stiff structure.
Ask yourselves - why is every skateboard made out of plywood and not carbon fibre or aluminium?
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
why is every skateboard made out of plywood and not carbon fibre or aluminium?
Pace
Join Date: Oct 2005
Location: USA
Posts: 3,218
Likes: 0
Received 0 Likes
on
0 Posts
But there must be reasons why would is not used much by manufacturers today? probably that once the initial moulds are made its easier to mass produce in composites?
A wooden spar is also difficult to inspect. A wooden spar can look good visually, but can be rotted internally. Short of taking core samples, one is left with exterior visual inspection of the part, and a coin tap, which doesn't tell much, most of the time, on wood. Properly preserved, wood spars and wooden airplanes can be around a very long time. I'll go fly a wood wing any day of the week, and I'm quite happy to do so.
Wooden structures gain no strength from screws or nails; the strength of a wooden structure is it's construction, and it's glue. Some older glues, particularly some of the older urea-formaldehyde products such as Aerolite, have been discouraged and fallen from favor in the US and Australia. Be forewarned that in the UK, Aerolite is still approved, and it's a poor choice. Most older wooden equipment is built with Aerolite, and it can fail. Better choices with resorcinol and epoxy are available, but even with these glues, proper humidity of the wood and ambient air, as well as proper fit and clamping pressure are important. Unlike metal structures with rivets, in a wooden airplane, you've got nothing mechanical holding things together most of the time. You've got glue.
A proper glued joint will be stronger than the material it bonds, or at least as strong; a failure in a properly bonded structure will never fail at the glue joint, but in the surrounding material.
That said, as Pilot DAR noted, the project is never over until the weight of the paperwork exceeds the weight of the aircraft.
Join Date: Jan 2001
Location: In the boot of my car!
Posts: 5,982
Likes: 0
Received 0 Likes
on
0 Posts
Adam
Just googled this snippet for you and yes they are changed every race
Just googled this snippet for you and yes they are changed every race
Well the skid block has to obey to some rules...which I'll have to post next time cause I left the terchnical regs at home!
And it's not 100% wood....it's a kind of composite made from wood fibres and a benzo fenolic resin. I contacted Jordan enquiring about the skid block and the only thing thety replied was that it was wooden!!!!this means that it isn't wood but most of it is wood (the fibres)!
A composite is made up by 2 parts the resin and the reinforcement (in this case the fibres). When you look at a tree you see wood fibres and cellulosic resin! In F1 the only thing they do is change the resin!´~
Minardi for instance uses something very similar to ply wood and using special oils and vacum processes they are able to make this "composite", which has to heavier then water (according to the regs...and don't forget...wood isn't)!
And it's not 100% wood....it's a kind of composite made from wood fibres and a benzo fenolic resin. I contacted Jordan enquiring about the skid block and the only thing thety replied was that it was wooden!!!!this means that it isn't wood but most of it is wood (the fibres)!
A composite is made up by 2 parts the resin and the reinforcement (in this case the fibres). When you look at a tree you see wood fibres and cellulosic resin! In F1 the only thing they do is change the resin!´~
Minardi for instance uses something very similar to ply wood and using special oils and vacum processes they are able to make this "composite", which has to heavier then water (according to the regs...and don't forget...wood isn't)!