Can we go back to making planes out of wood again now?

[Pilot DAR]

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?

[SNS3Guppy]

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...

[madlandrover]

Yes. Especially if the aerobatic certification for Bellanca's Viking is revived!

[Rod1]

“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

[Pace]

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

[stickandrudderman]

The advantage of wood is that with wood you make it and fit it, with composites you make it, copy it in reverse, make it again and then fit it!

[Pilot DAR]

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....

[AdamFrisch]

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:

http://www.adamfrisch.com/images/wovenwoodbowl.jpg

Or how many complex shapes you can achieve with modern epoxy plywood construction:

http://www.adamfrisch.com/images/plywoodchair.jpg

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:

http://www.adamfrisch.com/images/deperdussin1.jpg

http://www.adamfrisch.com/images/deperdussin2.jpg

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.

[Big Pistons Forever]

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".;)

[AdamFrisch]

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.

[1800ed]

Plywood - the original composite. It's a fantastic material, but there are better things out there now.

[Pace]

Adam

I am not an aircraft builder ( Wood never have the patience or commitment :ugh:

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

[Genghis the Engineer]

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

[IO540]

Wood planes need to be hangared, which is an issue for most UK pilots.

[Pace]

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 :O

Pace

[AdamFrisch]

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?

[Pace]

why is every skateboard made out of plywood and not carbon fibre or aluminium?

I tell a lie Formula 1 cars do use wood for the skid boards underneith the car

Pace

[AdamFrisch]

Pace.

Interesting. Do they replace them after every race? Or are they left on as permanent part?

[SNS3Guppy]

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 number of reasons, really, some of which include public perception and liability. Cirrus designed an airplane that resembles a car, and it sells; it meets people's expectations of what's "modern." Many aerobatic airplanes have used and continue to use wooden spars because they make one of the best choices for a material that's strong, lightweight, and has no fatigue issue or limitation.

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.

[Pace]

Adam

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)!

[Jan Olieslagers]

In France they never stopped building planes out of wood - and to good results, too. One of the best ratio's of empty weight vs. max gross was/is achieved by a Robin plane made of mostly wood

[Charles E Taylor]

No Comment Necessary


http://farm6.static.flickr.com/5128/5296594870_d6cb2e7469_z.jpg (http://www.flickr.com/photos/46646477@N08/5296594870/)

http://farm6.static.flickr.com/5005/5304778350_119bb6e905_b.jpg (http://www.flickr.com/photos/46646477@N08/5304778350/)



Charlie

[Kolossi]

I believe the reason F1 cars use wood for the skid block is that its job is to reveal if the car setup has been made too low - in this case the "wooden" skid block will wear and part of the post-race scrutineering is to ensure that the skid block is above a certain height - if not it's been worn away so the car was setup with too low a stance. (BTW Pace - Minardi haven't raced in F1 since 2005 so that's a pretty old quote you've found there).

So if the above is correct this is a counter point to the intention with which it was posted - the wood is used specifically because it's WEAKER than the carbon fibre in this case.

Just picking up on this point though, I'm all in favour of wood in preference to CF in plane construction :ok:, and as for "naturally optimized, linearly organized cellulose composite", that's priceless BPF :D

[BackPacker]

Don't Airbus and Boeing use oak skid boards (and rather big ones too) on the tail when they're doing certification testing of new aircraft? Particularly taking off and landing with too low speeds, so that the tail scrapes the ground?

[Pace]

BTW Pace - Minardi haven't raced in F1 since 2005 so that's a pretty old quote you've found there).

Kolossi

Too fast a google ;) of course you are right but they are still used today

Pace

[Genghis the Engineer]

I had a fascinating conversation not long ago with a famous and scarily clever light aircraft designer.

He told me that he's currently doing experiments with carbon-balsa-carbon sandwich composition, and thinks that this might be, for him, the next generation of light aircraft design technology.

I'm pretty sure that EAP (the predecessor of the Typhoon) also used balsa, somewhere in the leading edges I think.

G

[aussiefan]

I am confused?

I thought a plane was used to shape/cut wood?:}

Some more info on f1,
The Skid Block was introduced as part of the safety changes that followed Ayrton Senna (http://en.wikipedia.org/wiki/Ayrton_Senna)'s death. The block is usually made of a material called Jabroc (http://en.wikipedia.org/w/index.php?title=Jabroc&action=edit&redlink=1). Jabroc is made of beechwood and built in a composite (http://en.wikipedia.org/wiki/Composite_material) process. Veneers (http://en.wikipedia.org/wiki/Wood_veneer) are layered and a high strength resin is used in each layer. They are pressurized and pressed, and brought to a certain and very consistent material density. As a result each Jabroc skid plank is all but identical in terms of wear rate and material density.
The plank does not in itself restrict airflow under the car. It is used as a gauge (http://en.wikipedia.org/wiki/Gauge_%28engineering%29) which restricts the minimum ride height attainable by the car. The closer the car is to the ground, the more efficient the front wing (http://en.wikipedia.org/wiki/Formula_One_car#Wings) and rear diffuser (http://en.wikipedia.org/wiki/Diffuser_%28automotive%29). The higher the down force levels, the faster a driver may corner. Cornering at high speed is considered excessively dangerous and so the skid block was introduced to counteract this. The thickness of the plank is one of the parc ferme (http://en.wikipedia.org/wiki/Parc_ferme) tests. If it is found to be worn beyond the allowed limit the car is disqualified.


Trying to compare F1 to aviation is a pretty big stretch, F1 teams have a virtually unlimited budget and will spend many millions to gain one tenth of a second a lap or less. A lot of F1 technology has made it into everyday life but has had to be made more reliable and cheaper to do so.

[blueandwhite]

Wood has some great properties for engineering, always has, but its a bit inconsistent in the raw form. Hence plywood is more consistent and used for that reason.

Wood covered with CF can have outstanding properties.

Jabroc is a often used as a tooling block in aircraft manufacture. Because its cheap, light, easy to machine and stable.

[MR.X99]

Perhaps as one would make a wooden boat.Nostalgia.But mass production No.I,m sure it will be agreed that that the cheapest manufacturing is in tubular and fabric combinations with some carbon fiber in there.

[AdamFrisch]

Def not cheaper.

Think about it - it would take exactly as long doing a hand lay up of wood ply sheet into a mold and then covering it with epoxy as it would a woven carbon fibre mat.

Wood is only labour intensive if one constructs with it as one did 100 years ago. It's moved on from cabinetry.;)

[MR.X99]

Help Save the Rainforest...delete this thread now! A ll we need is a A380 being made out of wood.:{

[Pilot DAR]

What a lot of facinating thoughts on the use of wood!

Mr.X99, how regrettable that I have started a thread which offends you such that you ask to have it deleted.... Did you actually bother to read my opening post before asking to have it deleted? It's not really about making planes out of wood at all.....

[Jan Olieslagers]

Unlikely though it might seem, it is not impossible there's a grain of humour in X99's last writing. I mean, even a fervent advocate of microlight flying could not seriously imagine a wooden A380, could he?

[blue up]

One advantage with wood is that it seems easier to see which bit has broken. I'm not knowledgeable on composites but I've 'got wood'!.
http://i82.photobucket.com/albums/j279/foggythomas/fred56.jpg

[A A Gruntpuddock]

Well, if it is that good, where are all the Mossies?

[Jan Olieslagers]

The greatest tradition of building aircraft from wood lives in France. Do you really believe they ever imported a single tree from Alaska into France? Most likely never even heard of it. But even in the USA, other woods were used, Oregon pine at least. And I remember a usenet discussion about a particular kind of wood only available in Australia that was judged very good for building aircraft.

[Pilot DAR]

and that Sitka spruce

The last aircraft woodwork I did was primarily high quality fir plywood, which I believe came from Finland, though I have used Sitka spruce.

The lesser availability of large trees, is giving rise to great development of laminated products for building construction. Where in the past I would have had trouble buying a single piece of wood 20 feet long, by 1 foot wide by 2 inches thick. Now, I have many lamitate choices in these, and greater dimensions. We don't need the big, perfectly straight grained trees any more, technology has advanced.....

[blue up]

Well, if it is that good, where are all the Mossies?

Mosquito Aircraft Restoration. Sourcing materials around the world (http://www.mosquitorestoration.com/materials.shtml)

and

Site updates (http://www.mossie.org/updates.htm)

"Normally on return only the crew chief met the aircraft along with ground transportation to pick up the crew. But now there were a number of men including the maintenance officer and operations staff waiting to inspect the damaged Mosquito. We returned to operations in a jeep rather than the old weapons carrier normally used.

"Repairing the damaged Mosquito is a story in itself. An English repair party arrived from the de Havilland factory. I visited the hangar and observed the civilians sawing the left wing off with a giant saw --a large lumber saw, similar to those used for cutting down trees. The workmen sawed right through the spar! They brought in a replacement wing, glued it on with splices, covered another piece of plywood over and placed a band around the splice joint with all kinds of screws in it.

"I met Bob Howle, my squadron commander and said, `My God, Major, I'm not going to fly that dam plane. They cut the wing off and all they did was glue another one back on. That thing will fall off. I'm not going to fly it.'

"He asked what I wanted and I told him I wanted a different airplane. He issued me a requisition form. They had a group of new Mosquitoes parked in a storage area to replace the ones we lost. I received a new Mosquito, had it painted in regulation markings and flew it.

"The maintenance officer, Capt. Robert Shoenhair, when he heard my refusal to fly the re-winged Mosquito replied, 'Hell I'll fly it.' And he did--he flew it the rest of the war!"

[SNS3Guppy]

The greatest tradition of building aircraft from wood lives in France. Do you really believe they ever imported a single tree from Alaska into France? Most likely never even heard of it. But even in the USA, other woods were used, Oregon pine at least. And I remember a usenet discussion about a particular kind of wood only available in Australia that was judged very good for building aircraft.

Not sure how you arrive at the idea that France has the greatest tradition of wooden aircraft; they're built all over the world. If you're thinking perhaps of WW1 aircraft, some were French. France certainly hasn't produced the most, the largest, or even the most innovative, in wood.

While spruce is a popular wood for aircraft construction, so is hoop pine, douglas fir, in some cases pine, and other types of wood as well. I prefer spruce for it's easy in working. it tends to be more consistent.

It does not come from only one source, however.

Wooden aircraft do not need to be hangared. It's preferable, but not necessary, any more than aircraft with wooden propellers must be hangared.

[Rod1]

“Not sure how you arrive at the idea that France has the greatest tradition of wooden aircraft”

Because the Jodel wing is still one of the most efficient wings in GA? Because Robin has been making a version of that wing in one of the best C of A aircraft for many years? Because this wing is made of wood?

In Europe there are probably more Jodel winged wooden aircraft by an order of magnitude, then any other type.

A DR400 with a given engine size will out perform any traditional metal aircraft with the same size engine. The new carbon aircraft have finally trumped it, but at increased cost. The Robin DR400 Ecoflyer is one of the best, most economical machines for the money you can get.

Have you not flown a Jodel?

Rod1

[Jan Olieslagers]

Thanks for agreeing, Rod1. But while I do not want to underestimate the Jodels and their legacy, I was rather thinking of new designs, admittedly of light or even very light planes, that use wood extensively, though mixing it with modern composites. The IBIS and Luciole are examples that spring to my mind but there must be several more.

[stickandrudderman]

My Falco is a lovely bit of wooden construction, it's just a shame it's not a bit lighter!

[SNS3Guppy]

Have you not flown a Jodel?

I considered buying one a few years ago...in the United States.

For all the wood airplanes you've got running around in Europe, however, I still don't think you'll come close in terms of numbers, to those found in the US. Not in general aviation, nor in general.

Some great products have come out of French Aviation, there's no question about that, both big and small. From the Cri-Cri (an unabashedly fantastic design, the great tragedy of which is that the designer won't sell plans to the US) to the A380, French products are not to be dismissed lightly.

To suggest, however, that the French have the most wooden aircraft and the best wooden aircraft, or that the French have the greatest tradition of wooden aircraft, would be rather misplaced.

The British Mosquito was a design of pure genius. A lot of countries have had wooden airplanes. Today wood continues to be a popular choice for homebuilt airplane construction. I'm building a wooden Sorrel Guppy, myself, though it may be another lifetime before it gets completed at the present rate of construction.

[lucaberta]

The early Mooney had a wooden wing but went to metal in the early 60's.my friend Stefano owns an early 1958 M20 with both wings and tail made of wood. Most M20 and M20A, the two models with wood wing and tail, have been modified by changing the tail from wood to metal after a few accidents due to wood rot that would not be visible and was undetected by the aiframe mechanics. My friend still has the wood tail but needs to perform strict load tests imposed by an AD issued after the accidents.

The real problem with wood, as someone already has pointed out, lies in the fact that there fewer and fewer wood masters out there who can really take of wood airplanes in the longer term. The wood master that my friend relies on worked on old Caproni planes, and has great experience with wood airframes and wings/tails.

While it's true that there quite a few modern machines such as the Pioneer 200 and 300 from Alpi Aviation, this is more of an exception than the rule. The Pioneers have their roots in the Asso series designed by Bepi Vidor, an italian wood artisan with great design skills. A lot of homebuilder from plans have built Asso planes in wood here in Italy. Not sure if the Asso series is known abroad.

Ciao, Luca

[Jan Olieslagers]

It is - sad memories - ASN Aircraft accident 04-JUL-2010 Asso Aerei Champion V OO-G08 (http://aviation-safety.net/wikibase/wiki.php?id=75483)
Says nothing about the plane as such, though, still less about wood construction. Think you are right about the required skills getting lost.

[blue up]

Heston Napier?
Napier-Heston air racer (http://www.airracinghistory.freeola.com/aircraft/Napier-Heston%20Racer.htm)

Imagine one of those going round the pylons at Reno! Another of those "what if" stories. 100 mph+ faster than the Mossie.

[stickandrudderman]

I was brought up on a housing estate that was built on Heston airfield and I've never heard of that 'plane before! You live and learn!:ok:

[AdamFrisch]

There can't be many ones left with the unmodified tail. However, the M20A wing was a wonder. It was faster than the subsequent alu wings and had a smoother ride. Everyone being terrified of wood, the A's can be had for a pittance these days. Absolutely nothing wrong with them.

[SergeD]

Most Robins are made from wood but in UK weather they would have to be in hangars :) It works OK in southern France but they still have to be watched.