The XPB Stage 1 underway.

[bexrbetter]

you should be using solidworks it can simulate loads on your structure which will show you where you can remove and add strength

It's called FEA, as mentioned, and I am currently using it as a guide.

 

I am fortunate that I have access to the cream of FEA software, and the people who can use it.

 

 

[geoffreywh]

There's not going to be a lot of wood in it is there?

 

 

[bexrbetter]

There's not going to be a lot of wood in it is there?

Co-incidentally I was talking to some Chinese today and they reckon with a mix of some melted down coke cans, old urine specimen jars and melamine that some lightweight imitation oak could be had.

 

 

[AussieB1rd]

old urine specimen jars

Guess that's where they get that lovely golden aged oak colour, just hope they don't start making Whiskey Barrels

 

 

[Pilot Pete]

Makes me want together a wriggle on with my Nieuport build

 

 

[Marty_d]

Makes me want together a wriggle on with my Nieuport build

Yeah he's a bastard, does more on his aircraft in a week than I do in a year.

 

 

[Kiwi303]

Yeah he's a bastard, does more on his aircraft in a week than I do in a year.

Mines still ink on paper sitting in a box covered in Irish stamps.

 

 

[Marty_d]

Mines still ink on paper sitting in a box covered in Irish stamps.

You bought the plans of something designed in Ireland???

 

(Just kidding guys... I love the place).

 

 

[Kiwi303]

Well, there are some issues, I haven't gotten a straight answer on whether Parrot Shooting should be done with a 12 gauge, or whether a 20G would work. Budgie Jumping seems a little unreliable as well and I haven't met anyone who can tell me which breed is most effective for Hen Gliding... Should I use a egg breed or meat breed?

 

Actually I bought an Australian translation and modification of a French plane.

 

Frank Rogers redrafting of the Jodel D.11 from Parlez vous Franquois to Gidday Mate, Wotcha upta!

 

Unused secondhand set sold to a Paddy and resold to me when he realised he'd never get around to using them a couple of decades later.

 

 

[bexrbetter]

 

Sitting my camera on a piece of polystyrene might not have been the best idea, hence the large jumping every time I drilled through ...

 

https://www.youtube.com/watch?v=s-3Nm9EzYvw

 

 

[bexrbetter]

Yeah he's a bastard,

I refute that, my Mum and Uncle were married 1 week before I was born.

 

 

[bexrbetter]

.. and how the bulk of the vertical braces are fitted into place ...

 

https://www.youtube.com/watch?v=618BBQCAFWc

 

 

[Pilot Pete]

Just asking, but why so many rivets along the vertical and not just two or so on the ends like a gusset with a couple in the middle to stop the brace from flapping? Not criticizing, genuinely curious as to all the rivets

 

Loving your posts by the way.

 

Very interesting

 

 

[bexrbetter]

Just asking, but why so many rivets along the vertical and not just two or so on the ends like a gusset with a couple in the middle to stop the brace from flapping? Not criticizing, genuinely curious as to all the rivetsLoving your posts by the way.

Very interesting

Because of the material gauges being used, the modules form a part of the complete structure, and are not just gussets per say. You also can't see some of the modules overlapping, as will the skins in key places for the same reason.

 

That 'vertical fitment' movie above is actually a doubler over the vertical where one module ends and the next starts with an overlap, the laser cuts so accurately that you can't see that there's 2 layers there.

 

It's keeping the weight down while keeping the strength up.

 

sdblo.

 

 

[flyerme]

I was going to post a pic of my build project. But I'm worried someone will have dig at the sticky tape and super glue... But that's how it says to do it? See the instructions come from china and quote " stick gusset longaron - riveting". , so I stuck it with glue and sticky tape and to tell you the truth it wasn't that riveting? Was boring actually .

 

 

[Pilot Pete]

Poor DAD jokes Timbo

 

 

[Pilot Pete]

Better show us a vid of your process Tim

 

 

[Pilot Pete]

Thanks for the explanation Bex

 

 

[Pilot Pete]

Just looking back at your first post. You could possibly just call the plane a " XPB" with a number to show what type it is.

 

Sorry, but I do tend to get a little involved in things such as what you are doing. Would love to be doing what your doing.

 

 

[AussieB1rd]

Coming along nicely Bex, enjoying this thread, have seen a few aircraft using ally angle and I guess that's ok but always thought them a little flimsy looking, yours is looking quite strong compared to the ally angle machines but like others have thoughts on weight issues, when you installed the vertical it seemed to slip in quite nicely but I would have thought you would have clamped it together to take out any gap to insure a very snug fit to take out any possible movement.

 

Await the next installment.

 

 

[bexrbetter]

I would have thought you would have clamped it together to take out any gap to insure a very snug fit to take out any possible movement..

Interestingly I am in 2 minds about that.

 

The verticals just slotting in between the longerons with a mm or 2 end clearance isn't a strength issue at all, the outer skin and the exponentially increasing inner skin area at the ends has well and truly taken over as the connection long before, but it's what people looking at it perceive is going on, so I did buy a little bench belt sander to trim the ends to a neater fit - although that trimming is something 51% builders should be doing.

 

And yes, the longer you look and play with it, square tube, or 4 flat sides anyway, is a logical method.

 

 

[Subsonic]

I have a question on this method of fuselage construction, I hope you don’t take it the wrong way.

 

My experience is old and probably out of date, but as a young apprentice AME (mech) for Qantas we were taught that all structural items in an aluminium airframe have no residual stress. I was never a proper “sheety” but I have seen many structural repairs and anywhere we had a longeron, stringer or section of skin repalaced it would be pre-shaped to exactly that required before fitment to the aircraft. For these types of members the material would be formed in the annealed state, and heat treated after forming to ensure no residual stress.

 

For small aircraft, is it common practice to leave residual stress in structural members?

 

 

[AussieB1rd]

For these types of members the material would be formed in the annealed state, and heat treated after forming to ensure no residual stress.

I maybe wrong, and will stand corrected if so, but he is basically just cutting to length and popping it together, and overlaying gussets and skins, and it all this goes together like a big kids meccano set, sorry for that analogy, if on the other hand there were welded joints, extreme rolling, or bending happening I'm nor sure how all this stress is introduced. As Pauline once said, Please Explain.

 

Where previously I mentioned ally angle being used in some home builds, vertical and diagonal bracing is pop riveted to the longeron and becomes a fairly rigid connection, in his method that mm or 2 mm as he says is a concern as movement can occur at both ends due to the brace not being connected directly to the longeron, also a smaller TEE gusset top and botton would probably be all that is required and further reduce weight and not subtract strength, but it can be said his top to bottom gusseting does add further strength but a trade off for weight, something I have noticed over the years with home owner builders is that they usually build over strength unnecessarily and maybe the case here.

 

 

[Subsonic]

I maybe wrong, and will stand corrected if so, but he is basically just cutting to length and popping it together, and overlaying gussets and skins, , if on the other hand there were welded joints, extreme rolling, or bending happening I'm nor sure how all this stress is introduced. As Pauline once said, Please Explain.

There is residual stress in the longerons because they are bent to shape and held there using other structure. In my experience (admittedly it's been many years since I worked on aircraft, and a very different type), a structural element was first formed to it's intended shape, then installed in the buildup. I've just never seen this type of construction before, and would guess that it would result in unknowns to determine ultimate load and fatigue life. I'm not an expert, so would need to defer to someone who is.

 

 

[AussieB1rd]

I'm not an expert, so would need to defer to someone who is.

Agree's and yes fatigue life is what was in the back of my head concerning gap movement, and that squeaky noise is annoying lol