PDA

View Full Version : Lightweight floorboard



Frenchy
05-30-2005, 05:53 AM
I just bought this lightweight stuff do do my floorboard,``econolite``
1/4 thick, 4x8sheet = 20 pounds, thin aluminium on both sides.Stronger than regular plywood.

http://www.signboards.com/Panel/econolite/Index.asp

Frenchy

mvivion
05-30-2005, 10:05 AM
If it doesn't say aircraft on it somewhere, it isn't legal in a certificated aircraft. Be careful you don't spend tons of time cutting and fitting something that your mechanic then has a fit about.

Boeing supposedly has some honeycomb material available surplus that is legal aircraft grade, that a friend of mine thinks might make good floorboards.

Just a thought,

MTV

Frenchy
05-30-2005, 09:19 PM
I`m posting in experimental and i `m building experimental, this product is not certified, but i think homebuilders should have a look at it.

Frenchy

T.J.
05-30-2005, 10:55 PM
Frenchy:
Did you have to buy a 4x8 sheet? What is the thickness? Have you compared its weight to a normal Cub plywood floorboard?
Thanks.

Frenchy
05-31-2005, 05:28 AM
Hi T.J.

Yes i had to buy a 4x8 x1/4 thick sheet,paid $ 132.00 cdn. I will use it to build my floorboard,bagage floor,rear seat bottom and back. My main concern was the weight and rigidity. If my memory is correct, ECONOLITE was 2/3 the weight of the plywood i was supposed to use ``without any protection on`` .Econolite doesn`t really need protection,it look like cardboard with a plastic core sandwich between to thin aluminium sheets ,it`s stronger than my plywood. i figure i can save 1.8 pounds on the floor alone.I found a 3x5 ins sample of the stuff in a RONA hardware store. If you are building exp. floorboard i think you should have a look at it before you buy plywood. After all that`s what exp. aircraft are all about.
If anyone is able to see the product,let me know what you think.

Frenchy

Ruidoso Ron
05-31-2005, 08:39 AM
Keep in mind that honeycomb needs a bushing of some sort to carry the crush loads, wherever a through bolt is installed.

Bugs66
07-10-2005, 11:51 PM
Looks like good stuff. Paintable too. I wonder where I could get a 3x5 sample in my area? Will have to research.

Bill Rusk
07-07-2006, 09:54 PM
Well my research was less successful. I had a number of composite materials sent my way. In each case to get the same strength as the ply it was as heavy or heaver, except for the kevlar stuff. At 700 dollars a sheet, roughly 4 x 8, I decided the cost was not worth it at this time. I can always go back and replace the floorboards later if I find a product I am happy with. Sigh.

Bill

Luke_theDrifter
07-07-2006, 10:20 PM
What is the weight difference between floors & baggage area made from Plywood, Aluminum, or Econolite????

I had it in my mind that Aluminum was lighter than wood, however I haven't done an apples-to-apples weight comparision. Anybody else?
If some has made this weight comparison, or has weights of Aluminum floor & baggage area, what thickness did you use on the front floor, rear floor, main baggage area, extended baggage area? Total weight?

Another consideration for my application, using Aluminum, is the ease of cleaning.

Crash
07-07-2006, 11:19 PM
As Ron said. You MUST install a solid bushing on every bolt that penetrates the floor board on any foam / waffel core type of floor board. If you don't, your rudder pedals after a couple of days will rock left to right 2 inches from the clamps being loose. Tighten the bolts again and the next day they're loose (foam center continues to crush). Some guys tried foam core between fiberglass sheet floorboards here in Alaska a few years ago and the ones that didn't install spacer bushings all wish they would have. Other then that, the stuff is most likely just fine. Take care. Crash

kase
07-08-2006, 12:20 AM
Weighed 1/4 marine plywood floor boards 7.6 lbs.

mvivion
07-08-2006, 07:25 AM
I was told that there is a very lightweight honeycomb material available from Boeing surplus as excess pieces for a nominal price. This stuff is supposedly very strong, and aircraft approved. Anyone know any more?

MTV

JimC
07-21-2006, 06:42 PM
Nomex core Gillfab is used for cargo floors in Boeings and other cargo aircraft. Comes in different thicknesses and is very light. Made by McGill, if I remember correctly. Googling Gillfab will bring it up.

CaptAmerica
08-02-2006, 01:08 AM
This is what my web research turned up, not every site was the same but most within a couple hundreths of each other, Econolite's spec sheet section was down, but here is a list of materials in apples to apples...lbs per cubic inch...

Lbs per cubic inch
Wood (Doug Fir) 0.0220
Lexan 0.0440
Carbon Fiber 0.0643
6061 Aluminum 0.0980
Titanium 0.1630
Steel 0.2830

JimC
08-08-2006, 10:32 AM
Gillfab isn't exactly apples to apples, since it's a composite rather than uniform density, but looking a couple of different types of Gillfab gives the following approximate range, approximately 1/3 to 1/2 the weight of wood for an equivilent thickness, and the nomex core makes it fire retardant. Looks like a good material to me, and it is already used for floors in aircraft:

Lbs per cubic inch
Gillfab (approx) 0.0073 to 0.0119
Wood (Doug Fir) 0.0220
Lexan 0.0440
Carbon Fiber 0.0643
6061 Aluminum 0.0980
Titanium 0.1630
Steel 0.2830

behindpropellers
08-08-2006, 10:47 AM
I have a design for a light weight floorboard using some techniques you guys have not yet thought about. Who wants to try one for their PA-18 project?


Hmm..... And I have a couple more lightweight ideas that nobody has touched on.... :o

JimC
08-08-2006, 10:58 AM
Gillfab 4809, developed for the Boeing 787 Dreamliner looks promising.

http://www.mcgillcorp.com/products/floorpanels.asp

JimC
08-08-2006, 10:59 AM
OK BP, I'll bite. What ? :-)

behindpropellers
08-08-2006, 11:58 AM
PM sent....

Dave Calkins
08-08-2006, 12:06 PM
I'm interested, too, behindprops.

How come no one has flamed Cap'n'Merica for simply giving density with no mention of how the structure would be comprised. :D

I know he has the brains to figure carbon, for instance, would be structured to have an upper skin seperated from a lower skin with foam, honeycomb, etc. This would be very much less in density than simply a hunk of solid carbon fiber thick enough to do the job of a floorboard.

Josh, why did you put just the density of each material? It makes plywood look like a champion on all counts, which it is not.

Also, anyone thinking marine plywood would be better or worse than some other type of plywood should think again. The 'plywood manufacturers association' has changed the spec on marine plywood and it now has a comparable 'void allowance' to most any AB sheet you'd go out to buy. For our application, more voids would be desirable, I just wanted to get out the bit of information about the loosening of the specs.

We all know that unless BehindProps has a magic wand, the lightest, stiffest, coolest-looking, most expensive floorboards are going to be carbon fiber top and bottom skins seperated by some type of honeycomb core or hi-tech foam. PERIOD. (and I have a very simple, quick, and light method to disallow crushing the core at your bolt holes)

:peeper :D DAVE

behindpropellers
08-08-2006, 12:06 PM
Gillfab 4809, developed for the Boeing 787 Dreamliner looks promising.

http://www.mcgillcorp.com/products/floorpanels.asp

I wonder what a sheet of that stuff runs....?

Sounds expensive...

behindpropellers
08-08-2006, 12:27 PM
We all know that unless BehindProps has a magic wand, the lightest, stiffest, coolest-looking, most expensive floorboards are going to be carbon fiber top and bottom skins seperated by some type of honeycomb core or hi-tech foam. PERIOD. (and I have a very simple, quick, and light method to disallow crushing the core at your bolt holes)

:peeper :D DAVE

I think I could get 30%-40% of the weight out of a set (compared to a normal wood floor) with this method/material/process and still retain the strength while still keeping the cost reasonable.....

Ill put in in the komputer tommorow before work and see where it comes out to.... :crazyeyes:

Dave Calkins
08-08-2006, 12:40 PM
Let us know!

DAVE

JimC
08-08-2006, 01:02 PM
Dave, what's your method of preventing crushing? I'm thinking in terms of a thinwall aluminum bushing topped by a stainless countersunk washer and bottomed with a fender washer or equivilent.
JimC

Bill Rusk
08-09-2006, 08:29 AM
More info. I found a sheet of composite material at a reduced price. I replaced my cargo floors, forward and aft. Here are the weights.
Plywood = Fwd 3 pds 6.1 oz
Aft 5 pds 1.6 oz
Total ply weight = 8 pds 7.1 oz

Composite = Fwd 1 pd 10.2 oz
Aft 2 pds 5.8 oz
Total Comp = 4 pds

Less than half the weight of plywood. Because it will not have the lateral forces applied to it from feet like the cockpit area floorboards I am not as concerned about wallowing out the attachment holes. You must use inserts as Crash mentioned if you use it where there will be stress and or movement. There are a lot of composites out there but many will exceed the weight of plywood. I don't find the weight in cubic feet to be very helpful so I have converted things to weight per sq foot for a given thickness.

.016 2024 AL = .230pds
.020 = .288
.025 = .360

There is enough sq feet in interior panels to save close to five pounds using .016 Vs .020. I have yet to find ANY composite that is lighter than .016 AL.


Composite = .40 ppsf
1/4 Mahogany ply = .78 ppsf
6mil poplar ply = .85 ppsf
1/4 Birch ply = .93
Home depot ply = 2.0

Your 1/4 inch composite needs to be .6 ppsf or less to make it worth the trouble. Plywood has a much higher modulas of elasticity so it will flex and return to shape without any permanent deformation. The composites will flex some but often they will go plastic and show permanent deformation at a lower stress level than plywood. Thus composite use on floors under the seats and or for the seat bottoms, (seatbacks may be OK) may not necessarily work out as you will need a really strong composite which may end up being heavier than the comparable plywood.
There are a lot of different types of materials, like Al, nomex, kevlar, fiberglass, etc. Each with different properties and weights. The stuff that is lighter than the ply is usually EXPENSIVE.
http://sparky.supercub.org/photopost/data/500/medium/Picture_0192.jpg

This is my upper baggage compartment using composites. Smithcub.

Crash
08-09-2006, 10:55 AM
I used .016 aluminum on all side panels but went up to .020 for the upper and lower extended baggage "floor boards" with hat channel stiffners where needed. Crash

Mauleguy
08-09-2006, 11:24 AM
www.robotmarketplace.com/marketplace_carbonfiber_cust.html

.023 thickness 48"x96" CARBON FIBER sheet 4.066lbs per sheet weight, a little expensive. This is what I am using for my side panels.

Much lighter then aluminum!

Greg

pak
08-09-2006, 11:27 AM
I have seen heavy fabric used very successfully on the upper rear baggage. I currently have .020 aluminum in mine but would think hard about using fabric next time around.pak

behindpropellers
08-09-2006, 01:08 PM
Took some time before work and then some more at lunch to see what my design would weigh.

I used a density of .0216764 lbs/cubic inch

Stock design came out at 3.04 pounds for the front floorboard.

My revised design came out at 1.976 pounds.

So with my method getting 30% of the weight out would not be too hard.

Im not sure if it is worth the extra hassle. The cost is about 3-4 times what a normal 2'x4'x1/4" piece of wood would cost.....just for ballpark.
Tim

Dave Calkins
08-09-2006, 01:38 PM
Homemade composite floorboards are within the realm of any of us who are willing to mix epoxy accurately and follow a few instructions.

Making test pieces for destruction to compare to other materials choices takes the guessing out of what to use. Also, composites retailers (Plaschem Supply in Anch.) have competent persons willing to assist in design.

A foam core with fiberglass cloth or carbon fiber cloth applied to both sides with epoxy resin wetting the cloth can be built on your workbench.

Jim C., my simple method for disallowing compression of the cores of composite floorboards is as follows:

After drilling the bolt/screw holes thru the material, the core material is 'gouged-out' in the area within, say, 5/16 inch radius of the hole centers without changing the size of the hole in the top and bottom skins. Then a 'Putty' of epoxy mixed with a thickener (a thixotropic agent such as cabosil) at a ratio providing a putty thickness like peanut butter is placed in each gouged-out hole. After curing, each hole is redrilled and localized crushing is impossible due to the putty.

This method is simple, does not require precision tools, and has the advantage that the 'hardened' (putty-reinforced area) is adhered to the structure of the floorboard.

I've seen a fabric interior and baggage floors and sides that appeared to work very well. I'm thinking a zip-in cordura interior would be nice, and provide easy access. And the stuff is pretty tuff. (trading weight for tuffness and tuffness for weight) everything is a compromise.

DAVE

JimC
08-10-2006, 05:44 AM
Dave, I've been using fabric upper baggage floors in J-3's for years. Works great. I run them back to just short of the trim jackscrew. Good for holding fishing poles and other such stuff.

Your stiffening technique works fine as well.

Dave Calkins
08-10-2006, 01:40 PM
Floorboards. Who needs 'em?

I've been thinking that a guy could get away with partial floorboards if he wanted to.

Floorboards in the area of the rear stick are needed so your passenger has a place to put a foot when they get in, and the pilot and passenger need a place to put their heels. Everything else is superfluous.

Stock floorboards don't keep stuff from falling down in the belly, so that's not a good reason to have a complete set.

If light weight is king why not eliminate most of the floorboards?

Just and idea. :peeper

T.J.
08-10-2006, 02:15 PM
delete

behindpropellers
08-10-2006, 02:46 PM
Floorboards. Who needs 'em?


If light weight is king why not eliminate most of the floorboards?

Just and idea. :peeper


Hey....

If you are taking the floorboards out you can take the brakes off!!

Will work like this Car's brakes..

:lol: :lol: :lol: :lol: :lol: :lol: :lol:

http://bedrock.deadsquid.com/img/group/flintstonecars/fred_wilma_baby_car.jpg

Dave Calkins
08-10-2006, 03:51 PM
discussing the 'sans-floorboard' Cub yesterday in the hangar, Fred's car brakes were mentioned.

Funny how ideas can be developed in parallel, without any communication.

:D DAVE

Steve Pierce
02-07-2012, 08:04 AM
Had a friend fly in yesterday in his Legend Cub with honeycomb floorboards. Seems he had to jab a brake to avoid a helicopter at his home airport and pulled the two bolt brake pedal mount doubler right through the floorboard. This part looks identical to the stock Piper part. Needs more area to distribute the load. Seen this on plenty of 30-40 year old wood floorboards. Easy fix was a large stainless steel plate. Just something to consider.

tempdoug
02-07-2012, 09:11 AM
Steve, the lightest way ive seen to stregthen that up is to ad a tab on top the floorboards that goes from the brake pedal attach clamp bolt up to the rudder attach clamp bolt. I did that in mine but i have plywood, but it transfers the load right to the frame. I think i could break the back pedal off before the front would ever wiggle. On something lighter than plywood it probably wouldnt hurt to put a little wider washer underneath on the brake brace channel bolts also with the tabs. Spread the load some? The brackets can be made for under 25 cents.

444LZ
02-08-2012, 12:11 AM
How does a (new to planes guy) like me know what types of floor board / side board materials can be used in certified cubs?

Little_Cub
02-08-2012, 05:13 AM
444LZ give Phil, Steve or Jim a call at CAC Plastics.. they have light (certified) honeycomb material that is paint-able. For re-enforcement of bolt holes they simply cut the hole large, plug with resin and re-drill to size. They are just waiting to get some more orders to save on freight.
Several weights and thickness but 1/4" two ply (HD) is 8 OZ/Sq Ft and tough!
CAC = 907-376-7111 or phil@cacalaska.com

Steve Pierce
02-08-2012, 08:12 AM
Use what Piper used, 3/8" plywood and aluminum. Tried and true in certified.

mike mcs repair
02-08-2012, 10:52 AM
Use what Piper used, 3/8" plywood....

1/4"???????????

Steve Pierce
02-08-2012, 02:05 PM
Ha, yes Mike 1/4". I think some sort of composite iver the honeycomb would help, something beside the stock attach plates to spread out the loads.

AntiCub
02-09-2012, 01:24 AM
Floorboards. Who needs 'em?

I've been thinking that a guy could get away with partial floorboards if he wanted to.

Floorboards in the area of the rear stick are needed so your passenger has a place to put a foot when they get in, and the pilot and passenger need a place to put their heels. Everything else is superfluous.

Stock floorboards don't keep stuff from falling down in the belly, so that's not a good reason to have a complete set.

If light weight is king why not eliminate most of the floorboards?

Just and idea. :peeper

My current plane doesn't have floor boards at all. Just heel cups on the base of the rudder pedals. :D

Phil

Darrel Starr
02-11-2012, 02:35 PM
I used very stiff 6mm (1/4 in) 12 ply all Birch plywood from B&D International Inc. in Tacoma, WA. It is imported from Finland. Weight stated by the supplier is 0.92 lb/ft sq. After one spray of Epoxy Varnish I weighed a sheet at 0.98 lb/ft sq.
www.bd-international.com (http://www.bd-international.com)
5388

5387

Olibuilt
02-11-2012, 04:54 PM
My current plane doesn't have floor boards at all. Just heel cups on the base of the rudder pedals. :D

Phil

I don't see the purpose of putting floor boards under the front seat and so on... When I drop something small in my Cub it usually falls in the fabric belly anyway. Would make cleaning easier.


Anybody have pictures of light weight partial floor board?? Was thinking aluminium partial floor boards with dimple die holes in it....

skywagon8a
02-12-2012, 07:18 AM
A lot of warbirds only have a strip of aluminum as wide as a human foot under and aft of the rudder pedal. Just something to rest your foot on. Just bend some corrugation strips in it to stiffen.

Bill Rusk
02-12-2012, 09:24 AM
I am currently working on getting a honeycomb carbon fiber material for the floorboards and baggage. You can save 8 to 10 pounds by using this stuff. It is quite difficult to get. Everyone advertises one thing and delivers another. 8 week lead time is the norm. And they usually have minimum orders that make it impractical for individuals. They also do not want to talk to you unless your name is Boeing, Gulfstream, or Airbus Industries. If and when I get all this sorted out Javron will be carrying it and selling it. If you are interested give him a call as he does not have any feel for what the demand will be.

Bill

Rob Murray
02-12-2012, 11:20 AM
I've used Boeing's alum honeycomb for other purposes but not on my Cub. I remember a story about flight attendants spike heels denting the stuff, whereas a fully outfitted marine did not. And as others have pointed out it needs reinforcing inserts where bolts and other hardware might be located. Different cell sizes and thicker top skins might solve some of these problems, but custom production is expensive. Which probably makes other materials (Gillfab) worth looking at.

Amy
02-12-2012, 12:09 PM
Just a quick note:

Remember that floorboards are also a crashworthiness concern. There was a Super Cub nearby here that underwent a nasty groundloop after getting picked up by a gust upon landing and the wooden floorboards shattered. The pilot only suffered minor injuries in this case, but it is something to consider. For what it's worth, Part 23 does not allow wooden floorboards because of the shatter concern and potential for injury caused. It is my understanding that this could be a concern with composites as well. I am sure there are ways to overcome this but those pictures of the incident Cub creeped me out! Don't want my legs down in that crumpled mess (thankfully I have a weight advantage on most other Cub pilots ;))

moneyburner
02-12-2012, 03:50 PM
The place where I get some of my guitar-making stuff has DuPont Nomex in 16" x 22" pieces; 1/4 x .080", 1/8 x .080" and 1/8 x .060. Some folks are using it for soundboards on guitars. Boeing uses the stuff, so I'll assume it's approved materials. I'm willing to bet it doesn't burn as well as aircraft plywood does. It will need some layers of carbon fiber or fiberglass cloth, or both, and the appropriate resin. It's probably not hard to find videos or other media articles dealing with construction techniques.

http://www.lmii.com/CartTwo/thirdproducts.asp?NameProdHeader=+Nomex

I'm sure there are other places to get it, bigger sheets, etc.

AntiCub
02-12-2012, 04:29 PM
Just a quick note:

(thankfully I have a weight advantage on most other Cub pilots ;))

You know, most of use could probably save more pilot weight with a little effort than we could trim off our planes. Certainly true in my case! ;)

Phil

rayar3
02-13-2012, 11:02 PM
Walter Extra once said it's a whole lot easier for a pilot to lose 20 lbs than to remove 20 lbs from his airplanes! :)

Darrel Starr
02-13-2012, 11:58 PM
I know I should lose about two complete floorboards.

AntiCub
02-14-2012, 02:00 AM
I don't know about easier....

SpainCub
02-14-2012, 02:00 AM
I have a board with Nomex core on it. Itīs about 5x5" so itīs hard to judge how it flexes but it is really solid.

5419
Here is the source (http://www.nauticexpo.com/prod/bellotti-spa/sandwich-panels-plywood-honeycomb-30295-197074.html) for it.

Ta-ta!

Bill Rusk
02-14-2012, 05:48 AM
And you will note that to get more info on this product you have to fill out an info sheet and they will contact you. Finding and procuring this type of stuff is a PAIN. I have invested more hours on this one topic (and part) than any other part of the ENTIRE airplane. It works and it saves weight but you would think you were buying a nuclear reactor to get the stuff. So to help others, once I get this stuff sourced, I will make sure it is EASILY available to others. Probably through Javron, as I am not a cub kit manufacturer.

Bill

skywagon8a
02-14-2012, 05:56 AM
Has anyone tried making their own from a veneer (your choice of material) with a balsa wood core? Be sure to place a crush resistant material where all fasteners pass through. Or, how about the process that some of the plastic homebuilts use for primary structure with a foam core. I have seen samples of this which was cut out of a Glassair (like a window hole). Really tuff stuff.

OLDCROWE
02-14-2012, 08:01 AM
Anybody ever try end grain balsa core? Kind of old school in todays composite market but it is really easy to work with. I have used it in boat decks... easy to work with simple to reinforce point load areas, lay glass over (vacuum bag if you like).

Bill Rusk
02-14-2012, 08:10 AM
The issue with foam and or balsa core is that it is relatively easy to get it as heavy as plywood. The lightest core material is the nomex core 1/8 inch hex cell. The light plywood weighs .85 ppsf and a good honeycomb material will be .45ppsf or less, thus half the weight of plywood.

Bill

flybynite
02-14-2012, 08:42 AM
Foam and Balsa core materials: http://www.expresscomposites.com/foamcore.html

Nomex and polypropylene cores: http://www.expresscomposites.com/honeycomb.html

Small business located in Minneapolis. Usually keeps it all in stock and also carries vacuum bagging supplies. Ask for Jim.

To provide a "block" in the honeycomb for a fastener, drill a small hole in one face and chuck a small allen wrench in a drill, push the top (short leg) through the hole and spin it. Fill the cavity with an epoxy/microballoon or colloidal silica mix and let it set.

A possible plywood to use would be Lite Ply which is an Italian poplar. Very light weight but not too stiff or rot resistant. The 6mm is 5 ply. Next lightest is Occoume , then Meranti and Khaya or Sapele all in marine grades, 6mm 5 ply. GLII birch 6mm is usually 12 ply and would be about the same weight as the Sapele and also very stiff.

Wayne

SpainCub
02-14-2012, 10:43 AM
And you will note that to get more info on this product you have to fill out an info sheet and they will contact you. Finding and procuring this type of stuff is a PAIN. I have invested more hours on this one topic (and part) than any other part of the ENTIRE airplane. It works and it saves weight but you would think you were buying a nuclear reactor to get the stuff. So to help others, once I get this stuff sourced, I will make sure it is EASILY available to others. Probably through Javron, as I am not a cub kit manufacturer.

Bill

Wow, it's been a while since I was at their site. Probably hired a marketing intern or something :) (I hope I don't offend anyone!:P) but if you click on the X of the pop-up, then you get to the right window. I forgot it was all in Italian!

here is the link, there is a PDF on there! http://www.bellottispa.com/portal/portal/bellotti/settori-mercato/cantieri-nautici?page=2&pid=B00320

8856Charlie
02-14-2012, 01:40 PM
54205421I make a floor board laminate from the top side (finish side ) down, acrylic gel-coat on the top side, 5.8 OZ E glass, 5.8 OZ carbon,5mm PVC 4# density, 5.8 OZ carbon all layed up with a class I fire retardant vinalester resin. Comes out right at 8 OZ a square foot any color you want. I have had them installed in my cub since "98" approx. 900 flight time and still look great. I have not been able to find anything lighter that is finished and this finish is tough. I saved just over 4# on my cub with the two front boards rear seat bottom and standard baggage floor. I am just getting ready to send out samples for a burn test!

AntiCub
02-14-2012, 06:37 PM
I don't see the purpose of putting floor boards under the front seat and so on... When I drop something small in my Cub it usually falls in the fabric belly anyway. Would make cleaning easier.


Anybody have pictures of light weight partial floor board?? Was thinking aluminium partial floor boards with dimple die holes in it....

It certainly does make it easier to retrieve dropped hardware. Not to mention control inspections and lubrication. But I'm always paranoid I'm going to put a foot through the fabric, or bend a control rod getting in an out.

Phil

jimboflying
02-14-2012, 10:53 PM
I made carbon fiber floorboards with 1/32 plywood center and carbon fiber cloth on both sides using epoxy and a vacuum bag with peelply and absorbent pad. I radiused the corner for increased stiffness and an attach area for the side panels. The surface comes out with a tough finish, is waterproof, and weighed less than .032 aluminum. It was a fun process to learn. Pictures are in my photos but I can't seem to upload them to here.

pittsdriver
02-15-2012, 10:59 AM
And you will note that to get more info on this product you have to fill out an info sheet and they will contact you. Finding and procuring this type of stuff is a PAIN. I have invested more hours on this one topic (and part) than any other part of the ENTIRE airplane. It works and it saves weight but you would think you were buying a nuclear reactor to get the stuff. So to help others, once I get this stuff sourced, I will make sure it is EASILY available to others. Probably through Javron, as I am not a cub kit manufacturer.


Bill

Bill, Give Lancair a call, they have all kinds of honeycomb sheets including carbon fiber. Don

supilot
08-09-2013, 11:33 PM
If one was able to get some "FAA approved" Boeing floor board or cargo bay scraps, is there an advisory circular that would allow for a legal install in a certified cub?

Gordon Misch
08-10-2013, 01:25 AM
Sounds like a 'minor' mod to me - - I used some surplus honeycomb for rear seat base and back, with no paperwork and no disagreement from my IA.

supilot
08-19-2013, 11:45 PM
I've heard it's been field approved before.

I wonder if this AC below would allow it...

http://rgl.faa.gov/REGULATORY_AND_GUIDANCE_LIBRARY/RGADVISORYCIRCULAR.NSF/0/ccf7daac581048cd862575e6006ca078/$FILE/AC%2023-27.pdf

jimboflying
01-06-2014, 11:39 PM
I have been working on floorboards for my experimental PA14 made with Carbon fiber-end grain balsa-carbon fiber construction. I placed 1/4 inch plywood in the balsa in desired locations before processing in the vacuum bag to provide crush resistance in the area of bolts. I used West System epoxy, peel ply, and absorbent pad to absorb the extra resin and decrease weight. The end result was better than expected. The structure is very stiff, waterproof, well sealed, and light weight. The weight turned out to be 0.53 pounds per square foot which is 56% the weight of 1/4" plywood alone and also less than .040 aluminum. Besides it is kind of fun to do. Almost magic.
14531
145351453314534

nanook
01-07-2014, 02:47 AM
Looks good, mind saying what that total job is going to run.

Larry G
01-07-2014, 03:36 AM
I have been working on floorboards for my experimental PA14 made with Carbon fiber-end grain balsa-carbon fiber construction. I placed 1/4 inch plywood in the balsa in desired locations before processing in the vacuum bag to provide crush resistance in the area of bolts. I used West System epoxy, peel ply, and absorbent pad to absorb the extra resin and decrease weight. The end result was better than expected. The structure is very stiff, waterproof, well sealed, and light weight. The weight turned out to be 0.53 pounds per square foot which is 56% the weight of 1/4" plywood alone and also less than .040 aluminum. Besides it is kind of fun to do. Almost magic.
14531
145351453314534

i have never seen endgrain balsa sheets like that before. Can you provide a source for us. Looks very nice Jimboflying

flybynite
01-07-2014, 08:28 AM
Just a few places for balsa core material (and others). Express Composites is in the Minneapolis/St. Paul area if you make it into the Cities frequently.



http://www.jamestowndistributors.com/userportal/show_product.do?pid=1592&familyName=Laminated+Balsa+Core+Panels

http://expresscomposites.com/foamcore.html

http://www.defender.com/category.jsp?path=-1|2259972|2259998&id=2260006

http://www.fibreglast.com/product/end-grain-balsa/Vacuum_Bagging_Sandwich_Core
(http://www.fibreglast.com/product/end-grain-balsa/Vacuum_Bagging_Sandwich_Core)

jimboflying
01-11-2014, 02:50 PM
I finished the floor board set for the PA14 replica. They are made in three sections because of angulations to the floor and convenience for installation and removal as needed. They are a total of 88"long and 29" wide. They have a turned up lip on the edge to help with side wall anchorage and stiffness. They are 1/4" thick endgrain balsa as I previously described. There are 3 layers of carbon fiber cloth bonded together with West System Epoxy. Total weight is 11.1 lbs and 17.72 square feet for a total of .626 lbs/sq ft. finished on both sides. They are very stiff. I included plywood on the ends and in the middle where needed for anchorage points. Joewoodworker.com was a helpful site to learn how to do this process.

14566

mike mcs repair
01-11-2014, 04:38 PM
Total weight is 11.1 lbs and 17.72 square feet for a total of .626 lbs/sq ft.


pretty, but did that work out how you hoped??? weight and cost wise???

2024T3 .020 is .288 .032 is .461 .040" is .576 lb/ft and .050" is .720.... but I only use 050 front, 040 middle, 032 baggage, 020 extended baggage....

http://www.aircraftspruce.com/catalog/pdf/aluminumsheet.pdf

jimboflying
01-11-2014, 11:08 PM
Yes, I am pleased. The rear section came in between .032 and .040. The forward section was heavier because of the reinforcements for the rudder pedals and the control blocks. The angled sides also added a slight amount of weight but should give a nice surface for the Kydex to snuggle up to. When all is said and done it is lighter than plywood and should be more durable. Is it cost effective and time efficient to do? No, but it was fun and educational.

skywagon8a
01-12-2014, 06:27 AM
Well done Jim, I expect that the sound dampening qualities will out weigh the small weight penalty.

Olibuilt
01-12-2014, 07:45 AM
Very nice. CF is something I would like to lurn.

Steve Pierce
01-12-2014, 08:53 AM
Jim, Way cool. Thanks for the post, something I want to play with now.