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Author Topic: Junkers 87 B-2/R-2  (Read 2962 times)
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flydean1
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« Reply #50 on: October 12, 2019, 09:36:48 PM »

Another tape to use is drafting tape, the beige color like masking tape, but less sticky.
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TheLurker
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« Reply #51 on: October 13, 2019, 03:56:26 AM »

Crabby, Mike, Flydean

Thanks gents, the help is appreciated.  I already use the tissue "brass rubbing" trick, but the tape variation - Flydean's low tack suggestion is noted with interest - is new to me.    It's the sanding to exact fit, especially the chamfering of the edges that lie along the stringer that takes me the time.  Next time around I'll give Mike's x-grain cut approach a go.  Even if I can't knock the time down to as little as an hour it'd be very helpful to make the process a little faster as the nose on the 87 took me somewhere between 3 and 4 hours for 18 panels.

Cheers,
Lurk.
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billdennis747
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« Reply #52 on: October 13, 2019, 04:32:57 AM »

Just out of interest.  Am I alone in taking such an awfully long time to fit infill?  It can take me anywhere from 10 minutes to half an hour to get a panel in place and that's if I get it right first time.
 
I can do it pretty quickly. The trick is to do it badly then use lightweight filler and paint. Of course it doesn't work if you are covering for a tissue finish like Mike!
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Crabby
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« Reply #53 on: October 13, 2019, 10:01:20 AM »

Fiddlesticks Lurk! what's the big rush all about? You have the old sharpened ax hanging overhead? Play some soft piccolo music, and fiddle along with it on your Stuka.
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« Reply #54 on: October 13, 2019, 03:06:28 PM »

As the result of certain errors in construction The Directors have asked that Mr. Stewart (Foreman of the Assembly Shed) arrange lessons in basic numeracy for some members of staff in his Dept.  at the District Mechanics' Institute.

Or ...

When laminating parts remember that part order is n, n+1, n+2 and not n, n+2, n+1.  Even better, remember this before parts n & n+2 are glued together. Idiot.

Quote from: Crabby
Fiddlesticks Lurk! what's the big rush all about? You have the old sharpened ax hanging overhead?

No especial rush, but like most working bods, time for games is limited and the list of plans and kits that I want to get done is not getting shorter and if there are no axes to concentrate the mind there's always the scythe.  Smiley

Quote from: Crabby
Play some soft piccolo music...
Are you looking over my shoulder as I work!?  The pictured disc* has been one of a number on the gramophone whilst I've been working playing this weekend.

Lurk

*UK readers may be amused to note that that LP is on the SAGA** label.  All too appropriate no?
**No connection I'm sure, but an amusing coincidence nonetheless.
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abl
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« Reply #55 on: October 13, 2019, 03:48:12 PM »

...Another deviation from the kit.  Nose is part sheeted.

I have instructed my legal team to argue that this does not constitute a "significant" changes and should not, therefore, attract points...  Smiley

...Just out of interest.  Am I alone in taking such an awfully long time to fit infill?  It can take me anywhere from 10 minutes to half an hour to get a panel in place and that's if I get it right first time.

I use the method outlined by Mike above ("...cut a sheet of balsa crossgrain the width of the space between formers...") and I think it's reasonably quick, with practice. But it does rely on the formers being square to the keel.

Just out of interest.  Am I alone in taking such an awfully long time to fit infill?  It can take me anywhere from 10 minutes to half an hour to get a panel in place and that's if I get it right first time.
 
I can do it pretty quickly. The trick is to do it badly then use lightweight filler and paint. Of course it doesn't work if you are covering for a tissue finish like Mike!

You're OK with a tissue finish if you use either a) balsa-tinted filler (which is what I do) or just add a bit of acrylic paint to the white filler. And then, of course, if anyone mentions it you act outraged without actually denying anything.
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flydean1
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« Reply #56 on: October 13, 2019, 07:59:50 PM »

Recorder??? Looks like what we called a flute-a-phone.
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TheLurker
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« Reply #57 on: October 14, 2019, 07:50:52 AM »

Quote from: flydean1
Recorder???
Quite possibly more than you could ever want to know about the Recorder.  Never let it be said that The Lurker Industries Aviation Co. Ltd. is not firmly committed to its wider educational and cultural responsibilities.  Smiley
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Pete Fardell
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« Reply #58 on: October 14, 2019, 09:33:04 AM »

There's the screech of fingernails on a blackboard, there's the eardrum piercing whine of feedback from a dodgy PA system, and then there's the screams of a thousand tormented souls being roasted in the fiery pits of Hell. Sweet music, all of them, compared to the terrifying sound of...

...thirty primary aged school kids trying to play 'Go Tell Aunt Nancy' on slightly out-of-tune descant recorders. *shudder*
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Pete Fardell
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« Reply #59 on: October 14, 2019, 09:48:14 AM »

...thirty primary aged school kids trying to play 'Go Tell Aunt Nancy' on slightly out-of-tune descant recorders.
Which, funnily enough (and to get back on topic), was of course the inspiration behind the Stuka's infamous siren.
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flydean1
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« Reply #60 on: October 14, 2019, 11:37:33 AM »

Most I remember was in 6th grade.  The band director from the local Middle School conducted a music class using flute-a-phones made of some sort of black plastic.  Probably he was looking for band prospects.  I distinctly remember having some sort of reaction to the plastic in that after about 30 minutes, my lips started to go numb.  Other classmates reported the same.

To this day, I can play a radio, and that's about it.

Now back to your regularly scheduled Forum.
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TheLurker
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« Reply #61 on: October 14, 2019, 12:54:18 PM »

Quote from: abl
Quote from: TheLurker
...Another deviation from the kit.  Nose is part sheeted.

I have instructed my legal team to argue that this does not constitute a "significant" changes and should not, therefore, attract points...  Smiley

The Lurker Industries Aviation Co. Ltd. legal representatives, Messrs Grasping, Lyre, & Cheetham (Attorneys at Law, Public Notaries & Commissioners for Oaths) have received instructions from the Company's Drawing Office in the person of Mr. Barnes-Norway to contest this.  The Drawing Office maintains that no-where in the original design is any reference made to any means of sheeting by infill on any part of the main fuselage surface. The use of tissue covered card to cover the area around the tail-wheel is not considered by the Drawing Office to be sufficiently like infill to be classed as prior art as it uses both different material and construction techniques and is used primarily as a means of covering an area lacking stringers or other structural members which could not be covered by tissue alone unlike the nose which could be so covered.  Mr. Barnes-Norway and his team therefore feel that use of sheet infill is an entirely novel and therefore significant amendment to this particular design.  Mr. Barnes-Norway also said, "Yar boo sucks!", but that was after his second sherry and it may be that he will inclined to apologise unreservedly for this remark when he has *ahem* recovered his composure.


In other news.  Work continues v. slowly on the nose-block.

Cheers,
Lurk.

P.S.  Pete, be afraid, be very, very afraid.  I still have my Selmer Descant Recorder.  It's so old ermm, gosh it's nearly 50, that it's made of wood and I bet even now that I can make any class of primary school kids sound like world class virtuosi.  Smiley
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abl
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« Reply #62 on: October 14, 2019, 05:22:03 PM »


...Mr. Barnes-Norway and his team therefore feel that use of sheet infill is an entirely novel and therefore significant amendment to this particular design.


Mr Barnes-Norway will no doubt be aware that according to the OED, "Significant" is defined as "Sufficiently great or important to be worthy of attention"; a "significant" change would surely be (for example) a noticeable change to the profile of one of the flying surfaces which falls outside the variation expected during normal construction work. This particular - minor - change is hardly visible under most viewing conditions, once the model is finished.

Surely, then, considered within the ambit of the finished article, it must be obvious to m'learned friend that the addition of a few minor and hardly noticeable areas of local strengthening in an area where handling is inevitable can hardly be considered to be "important" or "worthy of attention". One has to look very hard indeed to see it at all!


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OZPAF
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« Reply #63 on: October 14, 2019, 10:58:34 PM »

Barnes-Norway? He must have had 2 fathers with impeccable Aero design capabilities! Smiley

John
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TheLurker
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« Reply #64 on: October 16, 2019, 03:30:35 PM »

Quote from: OZPAF
Barnes-Norway? He must have had 2 fathers with impeccable Aero design capabilities! Smiley
John

Reply No. 5, Page 1. Smiley

Well I think this looks like a moderately good representation of the front end of a Berthe.  Not great, wouldn't claim that, but definitely recognisable without squinting too hard.

Unfortunately some filler will be required, but I was expecting this especially around the formers so I'm not going to weep over it.  If I were able to drill holes true in block I would have cut the nose-block from a single piece of wood; unfortunately I can't so I opted for laminated construction.

Pics.
Top of nose with part from an Airfix 1/72 Ju 87 B2/R2 kit (A03089) for comparison, port & stbd views and one from the front.  That awful radiator is going to be covered with a stick on "decal" come covering.

The air intake "shoulder" should project onto the nose-block, but that detail is sacrificed for practicality as is the port side "shoulder".
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TheLurker
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« Reply #65 on: October 19, 2019, 05:39:32 PM »

In a previous post I promised to explain what's going on with the wings and this is as good a point as any.

The kit has the wings mounted on a single ply beam pushed into a transverse slot/socket in the fuselage. This beam also serves as the mounting point for the main UC legs. The problem I have with this is that it offers no easy way of covering the wing prior to mating it to the fuselage.  In fact the kit instructions leave covering of the wings until after they are fitted to the fuselage (and the UC likewise fitted to the wing) and require thin strips of postcard to be attached to the edges of the root ribs to serve as tissue attachment points to allow for this. I cannot see me ever getting warp free wings this way or even a half-way acceptable finish to the tissue.

So the following changes are made. 

1.  The UC legs now have a 1/32" ply core which plugs into a socket in the outer section of the wing.  See pic.

2.  The wings now have separate tongues, basically the kit beam cut at the mid-point, fitting into a new wing box on the appropriate former.  You'll see this on the side views of the fuselage in previous posts.

This means the wing can now be covered and, this is the reason for the shenanigans, pinned to a board while the tissue is shrunk and doped. The UC legs can then be glued and plugged in the sockets fitted and the warp free (one can hope) wings can be plugged into the fuselage. The ply tongues should provide enough support on their own, but, if you look back, you'll see that there's some sheet infill that the root rib can be glued to.  Just to be on the safe side.  Smiley

Why the explanation now?

This change to construction imposes some changes on the build sequence. To be able to test fit bits and be sure that they all align correctly the main UC legs and fuselage have to be built before the wing. This in turn means that that the wheels have to be built much earlier in the programme than is customary.  Which is what I've been doing today.

Build the wheels?  Ahhh... yes. This brings us to another deviation from the kit. The kit wheels aren't at all bad as these things go, but they are undersize and we need want wheels that are closer to scale diameter. Unfortunately neither kit nor built wheels are the correct scale width. To be able to fit scale width wheels you'd need to vacuum form or plunge mould the spats as the laminated sheet technique that is used cannot, for the sake of robustness, give the very thin spat side walls that scale width wheels would require. Never mind, it is kit scale after all.

The other change is to the way the wheel is mounted, see the pic.  The kit instructions require a U shaped bit of wire glued and pushed into the body of the UC leg.  This change also imposes some changes on the detail of the leg construction, but unless anyone's particularly interested I won't bore you with them.

Lurk
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abl
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« Reply #66 on: October 20, 2019, 12:35:07 PM »


> Build the wheels?  Ahhh... yes. This brings us to another deviation from the kit...

Luckily, wheels are free according to the rules and they can't do you for making new ones. Oh, wait, you want the points... Smiley
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TheLurker
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« Reply #67 on: October 20, 2019, 02:45:48 PM »

> Build the wheels?  Ahhh... yes. This brings us to another deviation from the kit...
>>Luckily, wheels are free according to the rules and they can't do you for making new ones. Oh, wait, you want the points... Smiley

Points for the wheels?  Nahhh.  They're an utterly trivial deviation, but they're part of the general rejigging of the UC and wing fitting.
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TheLurker
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« Reply #68 on: October 21, 2019, 03:51:27 PM »

The Board of Directors are seriously considering moving to piece work contracts as the current rate of production leaves a very great deal to be desired.

Or ...

This evening saw two wheel axles fitted, one wheel wire bent up and glued in place.  There's not much clearance for the wheel, see pics, so it's not a job to rush.   A December finish ? Aye next year. Smiley

Lurk.
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ZK-AUD
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« Reply #69 on: October 21, 2019, 04:46:43 PM »

I may have got to this party too late

I used a variation on your wheel spat theme on the little KK Lysander but  with a different positioning of the wire to provide better shock absorption - you can see this at reply #25.  This has proved to work really well in service

https://www.hippocketaeronautics.com/hpa_forum/index.php?topic=24003.25 
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TheLurker
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« Reply #70 on: October 22, 2019, 02:42:19 PM »

Quote from: ZK-AUD
I may have got to this party too late...
And you forgot to bring the sherry.  Smiley

I saw that at the time and was very impressed by it but even though I had the idea ready to steal - and I considered it - I decided to play safe and go with something I knew that I could build.
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TheLurker
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« Reply #71 on: October 24, 2019, 03:42:46 PM »

Plodding along.

Wheels painted, core of one leg built - see pics.  Pleased that the leading edge of the wheel cover has held up, was worried it might not.  Likewise pleased that the wheel is not far off centrally aligned.  Just the outer spat sheets to affix next then the really difficult bit; sanding everything to the correct profile.   
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TheLurker
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« Reply #72 on: October 26, 2019, 12:52:07 PM »

If you want to see wheels done properly, go to ZK-AUD's Big Lizzie build thread and marvel.

Meanwhile; here in the "B" stream the first leg has turned out moderately well.  Still need to do a bit more fine shaping to the top, rear of the spat, as it's a little on the fat side but I'll leave that until I've got the second leg done.  No sense in overcooking it at this point.

I doubt readers will be surprised to find that it took me nearly as long to make up the sanding sticks and profile gauges as it did to shape the leg. With luck the second leg will now take a day or two less to build than the first now I've got a reasonably good feel for the fiddlier steps in the assembly.

Lurk.
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Squirrelnet
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« Reply #73 on: October 26, 2019, 01:03:22 PM »

Looking good Lurk. I have a Guillows Stuka half built but the undercarriage and lack of strength in the kit version put me off. Your ply doubler is a great idea and should solve the problem . Also I like your range of sanding sticks, I'm inspired to make up some more myself. 

Chris
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TheLurker
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« Reply #74 on: November 03, 2019, 03:47:00 PM »


Quote from: Squirrelnet
... ply doubler ... should solve the problem
A thoroughly unoriginal idea, but I'm more than happy to take any credit there may be if it does help. Cheesy  Any chance we can see some pictures of your Ju87?

As for the Lurker Industries example, it marches very slowly.  Second main leg done last night.  Looks the same as the 1st - which is a bit of a relief -  so won't waste electrons or your time on another picture.

Finally got started on the deviant, oooh no... stop messing about missus, empennage. So far.... one rudder waiting hinges. Fin and stab. to be done as / if time allows this week.

The rudder is a mix of wood.  Medium for the rudder LE - to take the hinges - and soft for the remaining 1/16" bits. The 1/32" is probably medium, it was all that the stores wallah had to hand and one doesn't want to upset him unnecessarily Smiley .  This component was more like a peanut build than KS.  Lots of tweezer work and the gussets were just a wee bit on the fiddly side - but I was expecting that.

Today's lesson.  Dunking 1/32" x 1/16" strip in a mug of boiling water for a couple of minutes will soften it quite well, but not quite well enough that you don't get creases on a tight curve.

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