The XPB Stage 1 underway.

[bexrbetter]

I've been wonderin, if they can use these 3D printin thingies to do stuff, why can't they build a bigger printer an print a plane out of carbon fiber an cook it?

Carbon fiber filaments need to have a certain length to cross over and intertwine with other CF fibers, like your fingers interlocking, that's in part where it's strength comes from. It is extremely difficult to inject those long fibers through a nozzle and I believe currently they can only do very short lengths, otherwise the few very expensive, read military grade, that can run longer fibers can only do so placing the fibers in the same direction, either way there is low strength relative to what we have come to expect from CF.

 

Then there's the time it takes to actually print.

 

I think 3D printing has some fantastic possibilities, but more in the alpha stages such as producing a mold for fiberglass or CF, and prototyping.

 

 

In the meantime, wood and aluminium, with a slathering of fiberglass, remain and will remain the best choices for low volume small aircraft production. And since I am useless with wood, aluminium it is.

 

Mind you, a steel plane would work out very nicely too, and I would/could do one tomorrow, but alas, a marketing nightmare -

 

"No way is your 300kg steel plane lighter than a 300kg aluminium plane Mate, and would weigh double that of a 300kg carbon fiber plane!".

 

 

[Thunda]

WOW!

 

So it is possible, I had no idea it was already a reality.

 

Thanks for posting the video, it may have got others interested.

 

A plastic kit plane, now that I would be interested in.

 

The wings printed as a honeycomb unit with wiring, spars and fuel cells all in one piece attached screwed to fuse seats the lot.

 

Let's do it.

 

 

[bexrbetter]

WOW!So it is possible, I had no idea it was already a reality.

 

 

 

 

[Thunda]

Bex? ?????

 

 

[bexrbetter]

I have had joy with the rudder setup.

 

Early on I wondered about the cable routing and what I was going to use, pulleys, guides, outer casings etc and where they would be mounted. A few days ago I was staring at it all and it suddenly hit me, I might just be able to run a straight line up the middle of the plane, and booger me, I can, yee ha!

 

With nothing more than a few bits of guide tubes to guide them safely through the central wing spar casing and the fuse up the rear, the cables will run almost a straight line from pedals to rudder with only slight disturbance.

 

Here I am using some copper tubing because I had some laying around (always the best reason!) in case you were wondering, I will find some appropriate nylon casing later on, not very critical because as I said, the cable is running almost a straight line. You can actually site the middle of the front copper tubes looking through the rear copper tubes.

 

 

 

 

[ClintonB]

Nothing like when a plan comes together

 

 

[bexrbetter]

It works! Works damn well too.

 

One finger operation due to cables being basically straight from pedals to rudder and very little friction.

 

Please note the cables are just attached by a couple of flat washers squeezing them for the moment, that of course IS NOT the final fixture setup.

 

 

 

 

[fly_tornado]

no rudder trim?

 

 

[Bruce Tuncks]

A fixed rudder trim could be added at any time, for example if you wanted feet-off at cruise . But I doubt that it would be necessary because the loading on your feet would not be very much at all.

 

Looking good Bex.

 

 

[Marty_d]

It works! Works damn well too. One finger operation due to cables being basically straight from pedals to rudder and very little friction.

 

Please note the cables are just attached by a couple of flat washers squeezing them for the moment, that of course IS NOT the final fixture setup.

 

[ATTACH=full]51184[/ATTACH]

 

What are the tabs for on the outer pedals? Was it just to give you options if you decided to route the cables on the outside?

 

I know the 701 is like that - cables run from the outside back to the rudder, pushrods on the inside run forward to the nose leg.

 

 

[fly_tornado]

A fixed rudder trim could be added at any time, for example if you wanted feet-off at cruise . But I doubt that it would be necessary because the loading on your feet would not be very much at all.Looking good Bex.

looks nicer if its integrated into the rudder

 

 

[onetrack]

Just a slight diversion from the elegant cable setup - why the amount of work and crude appearance of the pedals, in cutting sections at 45 degrees, that are then welded at 90 degrees and gussetted?

 

Why wouldn't you just form the pedals from one section of tubing, bent with a pipe bender - thus eliminating cutting, welding and gussetting, and ending up with a smooth, professional-looking pedal shape? Is the tubing not amenable to bending?

 

Not criticising, just asking.

 

 

[Nobody]

Are you planning on installing toe brakes?

 

 

[Birdseye]

Don't forget the ashtray and pencil holders.

 

 

[bexrbetter]

smooth, professional-looking pedal .

Ouch!

 

Because it's the first set and not final. ... and I don't have a bender at this moment.

 

What are the tabs for on the outer pedals? .

Just a foot stop, lets you flop your foot naturally to the side.

 

 

[bexrbetter]

As some realise, everything ties together. Before I can set final pedal and stick positions, I have to understand where a person's body will be positioned, so now it's seat time.

 

Today I worked out some simple base frames, steel round tube through aluminium square tube and a couple of rivets. more work to do yet to fit them into the cabin securely yet easily removed in a single action, and then off to a local trimmers to see what they can do for bases and cushions etc.

 

Don't see too much into these pictures at the moment, there is a plan!

 

 

 

 

[bexrbetter]

More work on the seats today with folding backrest, included the LA (Large American) test of standing on them and jumping up and down violently ...

 

 

 

 

[onetrack]

I was hoping that there'd be a woven bamboo chair option, seeing as you're aiming at affordable aviation. Those seats look very expensive.

 

 

[Birdseye]

included the LA (Large American) test of standing on them and jumping up and down violently ...

Can't think of a better use for them.......large Americans that is.

 

 

[flyvulcan]

More work on the seats today with folding backrest, included the LA (Large American) test of standing on them and jumping up and down violently ...

The LA test may not be good enough (I don't know what loads this test imposes). Perhaps as a more measured test, consider sandbagging each seat with 900lbs representing a 150lb upper body at a 6g load factor (4g limit with 50% safety factor) and see how the frames get on.

 

Looking good (the aircraft that is)!

 

 

[bexrbetter]

The LA test may not be good enough (I don't know what loads this test imposes).

From a meter is 3.5g. 1.5 meters is 6g, aproximate figures. The "LA" comment was funnier.

 

As I like my ankles, I will not be using me for the final test after I select the appropriate seat base material.

 

 

[Bruce Tuncks]

I don't think the average glider seat would pass the LA test.

 

One time this glider I was launching kept losing its tow-ring when the load from the tug came on. But when the pilot got out, no fault could be found.

 

Yep, the weight of the pilot was distorting the seat down so that it interfered with the release mechanism.This took longer to figure out than it does to tell the story now.

 

 

[geoffreywh]

I like the welded rudder pedals, bends take up too much room. Brakes?. Personally I like drum brakes. (toe operated) There is no need for huge braking effect on tail draggers. Cables work very nicely for a looong time, are light, simple to fit and don't require fluid replacement. I got my wheels/drums from Marc Ingegno in Italy, have a look and copy , please.

 

 

[onetrack]

Interesting point re drums vs disc brakes. Can't see any major weight saving with drum brakes, when you consider aluminium or magnesium calipers are in common useage. With drums, you have shoes and drum weight to take into account.

 

Drum brakes are difficult to check lining wear on, disc pad wear is more easily checked. Disc brakes are better at shedding water and mud.

 

Cables can be kinked and often have uneven application rates due to high internal friction - and most importantly, drum brakes are notorious for uneven braking and pulling to one side. I vote disc brakes as the better option.

 

I looked for drum brakes in the Marc Ingegno catalogue and couldn't see any - but I did find disc brakes listed.

 

 

[bexrbetter]

I got my wheels/drums from Marc Ingegno in Italy.

I get my Nike copies from Charlie Qing for $15, you bloody snob.