The Bv 148, Dr Vogt's 'conventional' version of the Bv 141 - DONE

[loupgarou]

With half wingspan at 0 dihedral, then a sharp change, maybe Jodel had an hand in the project...
" Most of the designs are recognisable by their distinctive wings, which have 'cranked' dihedral only on the outer third.  From above or below, the wings are also distinctive as this cranked section of the wing tapers sharply towards the wingtip. "
From wikipedia: https://en.wikipedia.org/wiki/Jodel

[PR19_Kit]

It is VERY Jodel like, yes..

But Vogt must have been a real masochist to have designed the main gear legs going across the dihedral break on the 141!

He came to his senses with the 148 as they're in the straight portion of the wing. 

[PR19_Kit]

Now it gets complicated........

Here's the 'engineering drawing' for the mid-fuselage props on the 148.

You cannot view this attachment.

The green bits are the fuselage walls, the red bits are extra circular bulkheads that fit inside the fuselage, or inside the props, the orange bit is a hefty rod that's glued in the bulkheads and joins the cabin to the rear fuselage, and the yellow bits are larger tubes that are glued inside the prop bulkheads but rotate nicely over the orange rod.

At least that's the theory, I'm about to start cutting plastic for the eight circular bulkheads, I may be a little while.....

[Wardukw]

Ummm yeah Kit...that's gonna be fun ..in a masochistic sort of way but with plenty of tea and biscuits good quality thinking can be had .
I am wondering how the rear section of the fuselage is connected to the front 🤔

[PR19_Kit]

That's what the orange rod is for, the left hand end of it in the drawing IS connected to the rear fuselage and the right hand end connects to the cockpit.

The (longer....) wings are somewhere in the middle. 

Just started to convert the centre fuselage of the pale blue 141 into a tube to provide all the extra fuselage bits I'll need. Of course it starts tapering immediately past the TE of the wing, so that means I've had to file off all the wing fairings and fill in the resulting holes.

If it was easy everyone would be doing it of course. 

[Wardukw]

Oh mate it's because it's not easy is why we do what we do and it's only us wiff builders who can do it 

[PR19_Kit]

So VERY true.   

Here's the bit if sacrificial fuselage from the pale blue 141 after it's had it's wing roots filed off, a surprisingly quick process as the styrene was so soft. It's a lot easier making the resulting holes rectangular and filling them than it would filing a bit of styrene to the exact curved shape of the hole! It'll need a bit of PSR and then a short skim in my mate Pete's teeny weeny lathe to make sure it's nice and circular later on tomorrow.

You cannot view this attachment.

(a possible entry into the 'World's Most Boring Build Pic' competition. :-))

[Wardukw]

So VERY true.   

Here's the bit if sacrificial fuselage from the pale blue 141 after it's had it's wing roots filed off, a surprisingly quick process as the styrene was so soft. It's a lot easier making the resulting holes rectangular and filling them than it would filing a bit of styrene to the exact curved shape of the hole! It'll need a bit of PSR and then a short skim in my mate Pete's teeny weeny lathe to make sure it's nice and circular later on tomorrow.

You cannot view this attachment.

(a possible entry into the 'World's Most Boring Build Pic' competition. :-))

Nope nope ..I'm  not saying a thing ..I consider you a mate Kit and a mate leaves it up to other people to say how boring their build pic is ..that's what a real mate does   

[loupgarou]

As it's circular, wouldn't have been easier to find an appropriate sized pipe for that section?

[kerick]

As it's circular, wouldn't have been easier to find an appropriate sized pipe for that section?

Just don't get any glue where you don't want it!

[PR19_Kit]

As it's circular, wouldn't have been easier to find an appropriate sized pipe for that section?

I tried, and there's just nothing around that wouldn't need either building up or turning down to  match the 141's diameter.

[PR19_Kit]

Hmmmm, slight balls-up on the bulkhead manufacture process............

I cut ten 10 mm squares of 2 mm styrene, two spares,, drilled pilot holes and bolted them all together.

You cannot view this attachment.


Then Pete chucked them in his mini-lathe and turned the block down to the required 9.7 mm exactly, and it took almost no time at all, he does this sort of thing all the time. 

You cannot view this attachment.


Then we took the little block of circular bulkheads and test fitted them in the scrap 141 fuselage.

You cannot view this attachment.

Errrrr, a SLIGHT discrepancy in the diameter I'll admit, so it looks like we'll have to do it all again but at least we proved the technique! 

No, I've NO idea where the '9.7 mm' dia. measurement came from, I've re-measured everything on this job and NOTHING comes to 9.7 mm. It should be 14.6 mm so I'm chopping up ten LARGER pieces of styrene now................

[Old Wombat]

Hmmmm, slight balls-up on the bulkhead manufacture process............

You cannot view this attachment.

Errrrr, a SLIGHT discrepancy in the diameter I'll admit, so it looks like we'll have to do it all again but at least we proved the technique! 

No, I've NO idea where the '9.7 mm' dia. measurement came from, I've re-measured everything on this job and NOTHING comes to 9.7 mm. It should be 14.6 mm so I'm chopping up ten LARGER pieces of styrene now................

Measure! Measure! Cut! ... Oops! ... Measure! Measure! Measure! Cut! ... Bugger! ... Measure! Measure! Measure! Measure! Cut! ... You've got to be kidding! ... Measure! Measure! Measure! Measure! Measure! Cut! ... Oh, for f___sake! ... Measure! Measure! Measure! Measure! Measure! Measure! Cut! ...     I give up!    

[zenrat]

If you turn 14.6 upside down and squint (or put on the wrong specs) it sorta looks like 9.7...

 

[PR19_Kit]

It's sorted now, a whole set of new, larger, bulkheads have been chopped, drilled, turned, re-drilled and even RE-drilled umpteen times, and now they all fit over their respective rods and tubes.

Two of them are even installed in place in the fuselage extensions. RESULT!