3-D PRINTED EXPERIMENTAL ?

Homebuilt Aircraft & Kit Plane Forum

Help Support Homebuilt Aircraft & Kit Plane Forum:

rv7charlie

Well-Known Member
Supporting Member
Joined
Nov 17, 2014
Messages
3,376
Location
Pocahontas MS
One of the Cub clone kit makers has a program (approved by the FAA) where the kit purchaser comes to their factory and makes a significant percentage of the parts. He/she then leaves and the factory assembles and finishes the plane. You can be sure that a lot of the 'making' processes involve things like pushing the button on a press, after inserting the stock in the press.

The 3D print question is kinda moot at the moment (won't be in the near-term future), but various forms of 'subtractive manufacturing' (push a button, watch it cut) are already in wide use by homebuilders to make parts. I can't see FAA saying that those parts weren't made by the builder. The FAA doesn't expect you to make the aluminum tube or the rod-end bearings you use to make an aileron pushrod. If you 3D print the entire pushrod in carbon, would the FAA say you didn't build it? If you 3D print all the parts, and pay someone to assemble it, is that any different from what's happening now with the Cub clones? Once 3D tech advances to the point that entire assemblies (or the whole plane) can be printed, does that change anything? The FAA has gotten *much* more liberal with the 51% rule, in the 30+ years I've been around homebuilding. (Van's quickbuild kits used to require forming one rib, to meet the 51% 'fabrication' part of the rule.) They've gotten much more liberal with their interpretation because they've realized that safer a/c result.

Fun times are coming.
 

addaon

Well-Known Member
Supporting Member
Joined
Feb 24, 2008
Messages
2,342
Location
Kanab, UT
Big parts are easy, and strong parts are easy (although neither is cheap), but big strong parts are hard. There aren’t a lot of printers in the world that can do metal parts bigger than a meter. And by the point you’re talking about parts with continuous roving you’re not really talking about 3d printing as most people envision it.
 

tspear

Well-Known Member
Supporting Member
Joined
Feb 12, 2014
Messages
1,329
Location
Outside Boston
How about model airplane style? We print a bunch of parts and then put them together with a little glue ?

If you have enough cash, go for it.
Otherwise, 3D printing might be practical for smaller parts only. Depending on your budget for the printer, you are likely looking at 1ft max which would not work well. In addition, most of the low cost 3D printers produce parts which are not very strong.

I do not think the market exists yet, but at some point I expect some companies to offer 3d printing services on a large scale versus the current small scale you see.

Tim
 

4redwings

Member
Joined
Dec 8, 2020
Messages
19
Location
Virginia, USA
then there is this,stainless steel 3 d printed bridge
Wow! That is very cool! Although the one thing I really wanted to see was the printing machine but it wasn't featured on the website except for one small picture. It looks like there are quite a number of entities interested in the project.

Edit: Just found this:
It looks like a robotic mig welder. So you need a lot of time.
 
Last edited:

Riggerrob

Well-Known Member
Joined
Sep 9, 2014
Messages
2,960
Location
Canada
If you have enough cash, go for it.
Otherwise, 3D printing might be practical for smaller parts only. Depending on your budget for the printer, you are likely looking at 1ft max which would not work well. In addition, most of the low cost 3D printers produce parts which are not very strong.

I do not think the market exists yet, but at some point I expect some companies to offer 3d printing services on a large scale versus the current small scale you see.

Tim
Belt type printers have been available to amateurs for a good 3 years now.
Belt printers can print components of infinite length. ... even if only a foot or so wide.
Size of print is really only limited by size of budget.
 

gtae07

Well-Known Member
Joined
Dec 13, 2012
Messages
2,399
Location
Savannah, Georgia
It looks like a robotic mig welder. So you need a lot of time.
I've seen those posited before as a possible replacement for forging for things with low-medium production like engine monts or flap fittings, with slower part production times offset by significantly lower tooling investment and the ability to rapidly change production. They would still require post-machining like forgings but they don't need the massive presses and dies.

For really high production runs traditional forging probably still wins out
 

jedi

Well-Known Member
Joined
Aug 8, 2009
Messages
3,500
Location
Sahuarita Arizona, Renton Washington, USA
Have you seen the 3D house printed in concrete? A solid or hollow core foam wing could be printed with a similar foam printer and covered with fiber, either glass or carbon. No more need for Hersh Bar wings. The same for other aero surfaces and a large part of the fuselage.

A steel tube fuselage and engine and gear mount may be included for a strong crash cage or it could be manufactured by similar processes.

For tubular structures I have visions of a 3D printed cluster that is a receiver for straight cut tubes. No fish mouth needed.
 

wsimpso1

Super Moderator
Staff member
Joined
Oct 18, 2003
Messages
9,498
Location
Saline Michigan
Wow! That is very cool! Although the one thing I really wanted to see was the printing machine but it wasn't featured on the website except for one small picture. It looks like there are quite a number of entities interested in the project.

Edit: Just found this:
It looks like a robotic mig welder. So you need a lot of time.

It is a robotic welder. That can make thin skinned sparse structures difficult to make, then the material produced is annealled, not heat treated. That might be ok in 4130 where we use annealled steel at 66 kpsi, but in aluminum, we almost always use heat treated stock.

Then there is how much porosity is tolerable and what will be the fatigue strength?

Billski
 

addaon

Well-Known Member
Supporting Member
Joined
Feb 24, 2008
Messages
2,342
Location
Kanab, UT
Yeah DMLS (which is a misnomer — modern processes are melting / DMLM rather than sintering) is a great way to make certain parts. But machines with more than a 40 cm a side cubic volume are rare, and those over a meter are hens teeth.
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
5,085
Location
Thunder Bay
Have you seen the 3D house printed in concrete?
I just can’t imagine that ever being worthwhile in a world where bricks exist. Now if there was a way to make concrete on site using lunar regolith and in a vacuum that technology could be absolutely game changing.

Similarly I can’t picture 3D printing a whole airplane being worthwhile. Perhaps a machine that could convert from CNC hot wire cutter to water jet/laser to 3D printer. Hot wire out the major airframe components; water jet or laser the metal fittings and brackets; 3D print the ergonomic stuff like stick grip, flap handle, seat pan, etc. It would take some finishing work for sure but you could squirt one of a kind airplanes out of a shop somewhat efficiently.
 

Rik-

Well-Known Member
Joined
Sep 13, 2019
Messages
551
Location
San Rafael, California
For all the work, cost, headache and such, why not just make a mold and have the plane rotomolded. It would be light, cheap and strong.
 

tspear

Well-Known Member
Supporting Member
Joined
Feb 12, 2014
Messages
1,329
Location
Outside Boston
I just can’t imagine that ever being worthwhile in a world where bricks exist. Now if there was a way to make concrete on site using lunar regolith and in a vacuum that technology could be absolutely game changing.

Similarly I can’t picture 3D printing a whole airplane being worthwhile. Perhaps a machine that could convert from CNC hot wire cutter to water jet/laser to 3D printer. Hot wire out the major airframe components; water jet or laser the metal fittings and brackets; 3D print the ergonomic stuff like stick grip, flap handle, seat pan, etc. It would take some finishing work for sure but you could squirt one of a kind airplanes out of a shop somewhat efficiently.

I have actually read about a small structure built using a 3D printer and cement. If I recall correctly the research project built a small shed, but in any case. The belief was that the technology for printing a strong structure will be very expensive and complex. While in many places around the world, concrete or similar material is available at a much lower cost. So the design was pretty simple, use a nylon based large scale 3D printer to build the forms mimicking ICF. Then pour the concrete into the center core after dropping in limited amounts of rebar.
Other goals included testing the ability to to tackle complex shapes, and curves. The last piece was to somehow use the 3D printing to create overlapping air pockets in the nylon structure for insulation purposes.

Tim
 

Tiger Tim

Well-Known Member
Joined
Apr 26, 2013
Messages
5,085
Location
Thunder Bay
The 3D printed building I was thinking of basically had the nozzle pooping out a stream of thick, I assume quick-drying cement. No molds required. What it does require is a big gantry for the nozzle and whatever mechanism keeps feeding the thing, plus whatever equipment is necessary for set up and tear down of the machine. That’s a lot of effort when a truckload of bricks could just show up.

Likewise I think with current tech there’s probably a way to 3D print a human carrying airplane but the only thing it will be good at is being a 3D printed airplane.
 
Top