Foam

[Shane Crawford]

Would be nice if Wicks and Spruce provided the manufacturer's part number for the foam! That way people in other countries would be able source the products from their local distributors... Also, without this information how do people in the States know exactly what they are getting?!

Edited December 23, 2018 by Shane Crawford

[macleodm3]

The foam specifics (H45 PVC, Urethane, Last-a-foam) are in the plans of the aircraft you are building so that you can get the foam from any source and not be tied to any specific vendor.  Which foam product are you having trouble finding? I don't know for certain that the foam Spruce or Wicks ships to me is correct, but I trust them.  I then verify that the foam they ship matches the description of that foam in the plans.

It would be "nice" if they shared their sources, but a company makes money by finding a source for a product and then reselling that product in small quantities for a higher price.  For example, Garmin charges $400 for their GTP 59 OAT probe (needed for the G3X), but if we had Garmin's source we could buy the probe for less than $50.

[Shane Crawford]

Thanks for your reply. Was looking specifically at the Styrofoam / polystyrene foam for the wings. Trying to find out if I can source most of the materials locally before starting - Australia is a long way from most places, so it would be un-economical to freight large objects regardless of weight $$$.

[Kent Ashton]

I expect you can find this foam in Oz from an insulation company.

https://dctech.com.au/wp-content/uploads/2018/12/Styrofoam-LB.pdf

Dow blows various weights, densities and types of Styrofoam.  The stuff we want is 2 lb/ft3 extruded large cell, closed cell (rigid) Styrofoam (polystyrene) but I don't know the compressive spec.  A recent cozybuilder's post, mentioned "Styrofoam LB-H-XP", which weighs 20-70kg/m3 (1.2-4.39 lb/ft3).  Here are the specs   http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0944/0901b80380944976.pdf?filepath=xenergy/pdfs/noreg/291-71625.pdf&fromPage=GetDoc   and another reference for high compressive-strength foam

https://stars.berkeley.edu/assets/files/styrofoam_MSDS.pdf

I don't know a reference that shows both weight and compressive strength but I suspect that if the foam is about 2 lb/ft3, it's compressive strength will be OK.  Can't swear to that.  The first URL above says their foam has a minimum compressive strength of 300 kPa (43 psi).  The Cozy plans don't specify a compressive strength.

This boat dock billet is very close to 2 lb/ft3   https://store.eastcoastlumber.net/products/dow-dock-float-billet-10x20x96|102096B.html

In the early days, builders used boat dock billets but I believe there was a caution about buying foam with voids.  Personally, I think it all comes from the same Dow process so if the foam-type and weight are satisfied, it will be usable.  If you find some foam in Oz, post it because this question comes up from time-to-time.

Oh, yeah, when you talk to the dealer, you want to "build some surfboards".  🙂

[Shane Crawford]

Great, Thanks for all this information!

[Wisey]

How did you go Shane? did you find the parts needed in AU?

 

Cheers

[Royal]

I have been trying to find a company that can blow foam straight into a fiberglass shell without adding pressure to the skins. I think the ends would have to be open. Only reason doing it this way would be to save the 1000 hours of sanding it takes to make them straight. I don't know why someone hasn't come up with a better way to make the wings yet.  

[Countach74]

How are you going to get the fiberglass skin contour?

[Kent Ashton]

7 hours ago, Royal said:

I have been trying to find a company that can blow foam straight into a fiberglass shell without adding pressure to the skins. I think the ends would have to be open. Only reason doing it this way would be to save the 1000 hours of sanding it takes to make them straight. I don't know why someone hasn't come up with a better way to make the wings yet.  

When Rutan debuted "Moldless Composite Construction" in the 70s, it was a revelation how easy (EZ) it became to build near-perfect airfoils and aero shapes.  And it does not take 1000 hours of sanding--maybe a week or two of normal work after the structure is built.

I respectfully suggest you're going backward from that.  First you have to come up with perfect, finished airfoil skins built around wing spars, control linkages, attach points for ailerons, and attach points for the wings themselves.  There's 1000 hours of work right there.  Then the skins, spars and the rest must be jigged and held in the correct shape while you inject (expanding?) foam in the voids with some sort of machine you have yet to develop and do it evenly without distorting the structure. 

A "better way" to make wings is to pull them from molds or used matched-hole metal construction but that ignores the 10,000 hours it takes to make the molds or the $10,000 it takes to buy the hole-punching computer and equipment.

There is no free lunch.

[Royal]

Kent

2 hours ago, Kent Ashton said:

When Rutan debuted "Moldless Composite Construction" in the 70s, it was a revelation how easy (EZ) it became to build near-perfect airfoils and aero shapes.  And it does not take 1000 hours of sanding--maybe a week or two of normal work after the structure is built.

I respectfully suggest you're going backward from that.  First you have to come up with perfect, finished airfoil skins built around wing spars, control linkages, attach points for ailerons, and attach points for the wings themselves.  There's 1000 hours of work right there.  Then the skins, spars and the rest must be jigged and held in the correct shape while you inject (expanding?) foam in the voids with some sort of machine you have yet to develop and do it evenly without distorting the structure. 

A "better way" to make wings is to pull them from molds or used matched-hole metal construction but that ignores the 10,000 hours it takes to make the molds or the $10,000 it takes to buy the hole-punching computer and equipment.

There is no free lunch.

While I very much do respect you and your opinion, I really do because I have always asked and listened to the older guys when figuring out how to do something, I do know there are other ways to do things. I did come up with a way to make a fast, cheap and perfect mold. Found it by accident actually when we got a kitten 3 weeks ago. And with the CNC machines and 3d printers becoming extremely cheap I think its all doable.  I already 3d printed a CNC machine from my $200 printer. The automotive collision industry already has different kinds of foams that are low pressure and structural. Most of the companies are always willing to email you back. From what I have been reading and experience  in building things its better to improve the process than to change what its made off. Keep the foam, fiberglass  and all aspects about the plane. Just make it easier to build. Very little sanding. I believe it can be done.

[Countach74]

Check out the Personal Cruiser fold a plane technique. 

[macleodm3]

What do you propose to give the skins their shape?  
 

The Rutan methods are very easy to build.....  the only sanding needed is final contouring before paint (same type work needed when restoring a classic car).  
 

 

[Jon Matcho]

On 7/12/2020 at 10:14 AM, Royal said:

From what I have been reading and experience in building things [it's] better to improve the process than to change what [it's] made [of]. Keep the foam, fiberglass and all aspects about the plane [the same]. Just make it easier to build. Very little sanding. I believe it can be done.

You understand the key requirement (don't change the design), and we're all ears to how it can be easier to build. 

On 7/12/2020 at 11:26 PM, macleodm3 said:

What do you propose to give the skins their shape?

I am wondering the same thing. CNC cutting the foam, even around the fuselage, is the best I come up with.

[Anthony P]

I thought the idea was to mold the wing skin (and other parts) in one or two pieces and then pour/spray the "right" foam in there to create the current structure but with a perfect exterior finish and shape.  The molds are of course the problem, and the "right" foam can't balloon the skins while it's curing.

Darkaero is molding wing skins and then bonding ribs inside.

Another French company is making "cheap" carbon fiber planes with single piece molded wings that (I think) don't have any internal structure.

[Kent Ashton]

molds, molds, molds

You mold-talkers should get together and make a set of "traveling EZ molds".  For a small fee, a truck shows up at your house, unloads a full set of molds.  You pull skins off them and put them back on the truck.    I am sure Burt would have done that if he'd thought of it.  The man had no imagination.   🙂

[Royal]

I have to patent the method first before I go all willy nilly. I'm not  blowing smoke or some Keyboard Professional. And just because someone hasn't thought of it before doesn't mean it cant be done. I don't blame you for being skeptical. More big mouths out there on the internet than dirty hands.

[macleodm3]

20 minutes ago, Royal said:

I have to patent the method first before I go all willy nilly. I'm not  blowing smoke or some Keyboard Professional. And just because someone hasn't thought of it before doesn't mean it cant be done. I don't blame you for being skeptical. More big mouths out there on the internet than dirty hands.

Well... you can't patent a method to make homebuilt airplanes because people can do what they want.  Your idea can work, but it does seem to require molds, which is extra work.

Plans:  Cut foam, cover with glass (then filling and sanding)

Your Method:  Make a mold, cover with glass, fill with foam (no filling and sanding... use gelcoat like a fiberglass boat)

Molds are much better for mass production.... but moldless is less work at home for single airplane construction. 

Big Mouths... dirty hands?  I built this with my dirty hands....  

[Countach74]

Andrew- Where did you source your seat cushions? I saw your pics on Facebook with a mention of another builder giving you a lead on them.

[Royal]

4 hours ago, macleodm3 said:

Well... you can't patent a method to make homebuilt airplanes because people can do what they want.  Your idea can work, but it does seem to require molds, which is extra work.

Plans:  Cut foam, cover with glass (then filling and sanding)

Your Method:  Make a mold, cover with glass, fill with foam (no filling and sanding... use gelcoat like a fiberglass boat)

Molds are much better for mass production.... but moldless is less work at home for single airplane construction. 

Big Mouths... dirty hands?  I built this with my dirty hands....  

Should I post stuff I have built too?

[Royal]

71 bronco I built at my show. Custom cowl hood.

700 hp 73 trans for james contos

72 442 with a custom cowl hood and billet inserts

A brand new skin for a 77 datsun hatch. I am building this one still. Whole car is 5 inches wider and has an all new metal front and rear end. Glass has been changed too. 

Ls7 80 trans am with aluminum engine covers painted by Mike Levalle

https://www.thisweekinmotors.com/sema-2010-1980-pontiac-hells-ta-trans-am-protouring/

I also built the plugs and molds for anointed aero up until I moved. https://www.bing.com/search?q=anointed+aero&FORM=HDRSC1

I have many more cars i could post but you get the point.

OIP.jfif

[Kent Ashton]

10 hours ago, Royal said:

I have many more cars i could post but you get the point.

Good to see those because it shows you fabricate things and have the follow-through to bring them to completion.  They only thing I would caution is that the market for airplanes is tiny compared to cars so if you are doing something for fun, that's great but it may not be worth all the effort to develop a new aircraft build process.  Check out such projects as the "A-Solution" on this page  https://www.canardzone.com/forums/topic/21972-sales-ive-seen/page/19/?tab=comments#comment-64707    Lots of work there but no airplane came out of it (so far).   I see the aircraft and pilot numbers getting smaller, too.

From what I can tell, there is a lot of interesting, innovative airplane work being done but it is not on talked about much on the internet.  I guess people with really valuable knowledge and experience are in their shops building stuff.   For example, Robert Harris at EZJets.  Nice guy, DAR, knows everything about building composite airplanes but never posts on the net.  Another Is Klaus Savier who is an expert on ignitions and aero mods--almost never seen on the internet.  There are some smart people on HomebuiltAirplanes.com.    I suppose if I was trying to develop a new process, I would visit Mojave and some of the shops.  Talk to people at airshows and find out who is developing stuff.  Good luck.

Now here is a website I just saw today.   Some interesting things there   https://x-jets.com/burkut_jet.html

Edited July 15, 2020 by Kent Ashton

[Voidhawk9]

A lot of new ideas are shouted down by the 'build to plans' folks too. So the serious modders tend to be quiet online. But they are out there.

[macleodm3]

On 7/14/2020 at 11:09 PM, Royal said:

Should I post stuff I have built too?

Yeah I suppose you should when someone says you’re a big mouth with clean hands.

[macleodm3]

On 7/14/2020 at 8:34 PM, Countach74 said:

Andrew- Where did you source your seat cushions? I saw your pics on Facebook with a mention of another builder giving you a lead on them.

Ebay... bench cushion

[Countach74]

Thanks Andrew!!!