Heinkel He 111

[Roy vd M.]

Scratchbuilding a Heinkel 111 bomb bay - part 7

 

WARNING: THE HEREUNDER STEP PLAN WILL NOT BE USED TO CONSTRUCT THE BOMB CELLS. SEE NEXT POST. FOR A BETTER STEP PLAN SEE HERE: http://forum.largescaleplanes.com/index.php?showtopic=48155&p=548424

 

Okay, now for the 8 step build plan. I've actually timed each step. In total, carving one part takes 2 hours and 25 minutes.  

 

Preparations: 

 

- Construct the template for the part, as I described here: http://forum.largescaleplanes.com/index.php?showtopic=48155&p=546219 and http://forum.largescaleplanes.com/index.php?showtopic=48155&p=546261

- Construct the template for the holes, as I described after picture 4 here: http://forum.largescaleplanes.com/index.php?showtopic=48155&p=547645

- Construct the template for the folds, as referenced after picture 9 here: http://forum.largescaleplanes.com/index.php?showtopic=48155&p=546219

 

1. (takes 5 minutes) Take a smooth piece of (sufficiently large) brass. Take the part mold and put it over the brass sheet, aligning ONLY the bottom (important, if you align both the bottom and the side bordering to a holes part, the holes cannot be punched without torque damage). Use painters tape to stick both tightly together but don't cover any of the 18 holes. Then take the holes mold and place it on top of the part mold, aligning it perfectly with the holes of the part template. Stick it on with painters tape (no need to use expensive Tamiya tape here). 

 

 

2. (takes 30 minutes) Remove 2 pins of your punch&die. Do so at your own risk, chances are very high that you will damage the base of your expensive P&D set! But if you won't remove the pins you won't be able to punch all the holes. Place the 3-sheet-combination exactly above the 3.5 millimeter hole. Check this by ensuring that, on the OUTSIDE of the punch cilinder, each of the 4 grid lines touches exactly the half of the hole diameter. Difficult to describe without mathematics. I'd better demonstrate it in a picture (see below). I mean the grid line as depicted by the 4 arrows in the hereunder picture. Those 4 arrows also show the direction to look. 

 

After aligning the hole, check if the base and top of the punch & die are aligned as well. If not, reposition and align everything again. 

 

After aligning, enter the punch and even try to align that one as much to the center as possible (with a new punch & die set it should already be perfectly centered). 3x alignment check? Hit! If the small circular disk you just punched out is still stuck to the sheet, remove it by gently bending to- and forth. Eventually (for sure after some 20 times) it will get loose. Repeat this for all 9 holes. Then reposition the holes template to the other set of 9 holes and repeat. 

 

 

3. (takes 5 minutes) Remove the tape holding the holes template. Then use the scratch pen to (very softly!!!) mark 8 holes where the keyholes are. Use the template as a guide.

 

Then remove the rest of the tape. Check if the keyhole markings are correct. Use the scratch pen to make deeper markings. Next, mount a 0.8mm drill on your Proxxon or Dremel. The best way to tackle this with a Proxxon is to turn it on and then pull the knob back until the motor stops. Position the drill on the sheet and let the knob go. Holes are drilled correctly in place with no effort. This must be the easiest part of this whole scratch build. 

 

 

4. (takes 20 minutes) Mount a 0,3 mm. drill in a knife holder. Put the sheet over the punch & die base. Align the 'keyhole' hole over one of the two recently unpinned holes. Use the 'saw' to make the thin slit upwards. Repeat 7 times. Check the correct path constantly. Don't push the drill piece too hard or it will break. 

 

 

5. (takes 10 minutes) Sand the 18 vent holes with a Proxxon / Dremel machine equipped with a sanding ball. As a base, again use one of the two holes of the punch & die base where you had previously removed a pin. Take care not to bend or deform the sheet (also applies during the other steps). 

 

 

6. (takes 35 minutes) Stick the part template back on, leaving the octagonal holes uncovered. Use a scratch pen to mark the sides of the octagonal holes on the new part. Remove the tape. Take the sharpest knife you can find. Starting with a long side, align a ruler along it, start in a corner and cut to about halfway. Then start from the other side and end in the middle. Then do the other side of that same hole. Next, the diagonal and horizontal lines. Carefully take it out. Finally, file the sides with a squared file as long as necessary to get a nice result. Be careful not to bend the part while filing, use a cutting mat as 'holder' for example.

 

 

7. (takes 30 minutes) Stick the part template back on, attach only at the bottom. Next, use a ruler as guide and a sharp knife and carefully cut off the 3 sides in straight lines. Then, use a ruler and knife to mark the outer lines of the part (on top). Remove the tape and cut off the unnecessary metal. File until it looks the deal. 

 

 

8. (takes 10 minutes) Check which side looks nicest, that will be the outer side. Take the bending mold, put it in position (the beginning of the side walls can be distinguished by the above strips). Scratch the fold lines on the side opposite the nice-looking side. Start with the left and right vertical ones, then the middle vertical one, then the horizontal line. 

 

Scribe the horizontal fold line. Then, make two smaller horizontal fold lines (which will serve as attachment points for some internal structure later) as depicted on the hereunder picture. Finally, with a sharp knife, cut the sides of the latter two to-be-folded strips loose (see picture). 

 

 

And there it is, a finished base part! Beside preparing the 3 template pieces and the research, it apparently takes 2 hours and 25 minutes per piece. 2 ready (the mould one I'll probably not use in the build as it looks less attractive than the other ones... but perhaps, for a change, I'll use it anyway), 6 to go. 

 

 

Time spent building, planning, drawing plans: 71H. Studying: 43H.

Edited March 12, 2014 by Roy vd M.

[Heavens Eagle]

Something just occured to me while I was looking at your latest post Roy. That being the years of experience I had doing sheet metal prototype work.

 

What hit me was that the mor complex you make a single part, the harder it is to make it exact with hand tools and the easier it is to FUBAR it at the last step. Basically you are trying to make the whole box out of 1 piece of material. To do this you have had to modify your tooling and if you make a mistake, the whole part is damaged instead of just half. Which brings me to my suggestion, instead of making the whole box as 1 piece, make it as 2 pieces, a side with the holes and the side with the large hole. Then when you get ready to bend the parts, just make an accurate setup and bend them all the same.

 

The positives to this are if you make a mistake only a half part is lost not the whole part. Bending can be made more accurately as you only have 1 bend and can do that with the tool accurately. Punching the holes can be done without messing with your tool and possibly damaging it.

 

Then make a small jig to hold the parts while assembling the half parts together.

 

Also you could make one thick heavy pattern part carefully to use as a guide for punching the thin brass and the 16 small parts would be easier to make quickly and accurately. You could even use superglue to hold he thick pattern piece to the material while punching the holes, then get the CA to release by heating the part/tool with a lighter or candle.

 

Just a suggestion, and the pattern piece should be .020 to ,030 inchs thick minimum and actually put the punch down in the holes to align it.

 

Hope this helps.

[Roy vd M.]

Paul, that's some great advice. 

 

The original reason why I wanted to use one part (with 3 folds) was that the Eduard part made it clear to me that bends are much preferred to trying to glue the corners of thin brass sheet. After that I had noted the corner strips (L-beams) but I never made the connection to just use 4 parts for one cell. 

 

I could simply attach the beams to the sides of one part (2x) and then cover the fronts. It would make painting easier, carving easier, everything easier... Errors are not so bad...

 

So I have to thank you enormously!!! I'll just start anew haha

 

As regards aligning the pattern piece, I'd still have to look at the 4 'arrows' (see above picture). 

 

I'll add to my 8-step-plan above that it's old news

[Roy vd M.]

And, indeed, the punch & die needs not be damaged. 

[Heavens Eagle]

One thing I would reccomend for anyone doing fine detail work, would be to buy a good quality Jewelers saw frame and fine blades. For cutting plastics and light metals it can't be beat. I have a number of different saw frames and this one is my absolute favorite! It holds the blades securely and I was able to swap the tightening knobs to the right side of the frame out of the way.

 

http://www.riogrande.com/Product/Swiss-Adjustable-4-Saw-Frame/110060?Pos=17

[Roy vd M.]

Thanks Paul, could you use that for cutting out the octagonal part in a neat way? 

[Heavens Eagle]

I believe you stated that the material thickness you were using was .003 of an inch thick (0.08mm) correct? If it is that thin the problem that occurs is that the brass is thinner than the tooth pitch of almost any saw blade, and it will just tear instead of cutting.

 

The best way would be to cut that hole pattern out of brass at least .030 inch (0.8mm) thick. Then firmly superglue the part material to the pattern and use the patter to cut against as if it were oneblade of a set of scissors and your sharp knife the other blade and shear the thin stock. Can also then use a fine file to carefully finish the shape, just not too much so the pattern gets damaged.

 

The superglue should hold quite well until you heat it up. The heat won't hurt the brass, ut the glue will just give it up once it gets hot enough.

[Roy vd M.]

Hi Paul, after your tip and after a tip of my girlfriend (!) and a bit of thinking myself I now have a great method to making these parts. I'll describe it later. 

 

Here a preliminary picture of the result of both the side wall and the bow-tie shaped layer over it. This bow-tie part I'll have to redo by the way, because I made a mistake in the low-right diagonal as you can see. 

 

 

 

Without the bow-tie picture, here you can see a comparison between the previously made part, the Eduard part and the part made according to the latest-used technique. 

 

 

 

Thank you SO very much for your input. It looks much better now, is better for the material and is much easier to make. 

[Roy vd M.]

Here you can compare the Eduard part and the part as made from hours of measurements of several source pictures including a full frontal view of the side of a non-installed cell. Clearly Eduard didn't have that picture at their disposal, as the cell turns out to be taller than Eduard made it. Also note the thinner and slightly longer octagonal hole. This not only is more realistic in itself, but also makes room for 4 rivets in (horizontal) line on the strips along the octagonal hole. That would never have been possible on the Eduard part. 

 

 

Here on the background is one of the pictures I used to measure:

 

 

[Heavens Eagle]

Glad my input helped Roy. That is one of the things I really like about these forums is te positive inputs from folks. Iam learning from your build a lot as well. I have this kit for a future build and had planned on just using the Eduard PE for detail and being done with it. Now am doing a rethink and might just make these from scratch similar to you except I might use the .005 and .010 inch thick plastic sheet I have (will make a brass master though)

 

Something that would be nice for us watching once you get all your sizing figured out, would be a nice drawing showing the dimensions of the part.

 

Looking good! Keep up the good work!

[Derek B]

Inspirational work indeed Roy - Thank you for sharing your genius. This will be a very rewarding journey; keep up the good work

 

Derek

Edited March 12, 2014 by Derek B

[Roy vd M.]

Thanks Paul and Derek for your -very- kind words.

 

Paul, maybe you shouldn't write off he Eduard bomb bay. Certainly certain parts of it can be used (for example, the bomb doors cluster seems quite accurate, as do the bomb holders) and usually all of this would not be seen very well. There are only the two windows and, if you leave out the doors (or, like me, if you will have the doors opened) also from the cockpit windows if you look carefully. From the 2nd gunner's turret hole very little of the bomb room can be seen, I already tested that. I first wanted to superdetail these bomb racks because I just wanted to practice. I'm a novice builder so I can use all the practice I can get. But then I decided that I wanted to show the details of the 1st bulkhead. However the bomb racks were standing in the way. After a lot of thought eventually I decided to remove 4 bomb cells from the bomb room. They will be individually seen in the diorama I'll do. So now I have no choice but to detail them as well as I can. 

 

I also wanted to practice riveting and when I first compared the real life bomb cell pictures with the Eduard part I was confused, as there would be NO WAY I'd be able to position four rivets horizontally in a row on the very narrow strip along the octagonal hole. Only when I found better pictures I saw what was wrong. So also for my riveting practicing I needed a better version (originally I simply wanted to put the raised rivets on the recessed rivets but the recessed rivets turn out to be too plentiful and in the wrong places). So if you're not a rivetcounter that's another reason to just go with the Eduard bay. 

 

That having said, it would be wonderful if my thread could inspire a single person to do something like this as well. I'll keep doing my best to write down everything I learn underway and hopefully if you'll decide to scratch the bomb bays you'll be able to make use of it. When you do, remember that in the first post of this thread I made an index. All my scratchbuilding posts are listed in the correct order. So when I'll be detailing the wings and we've come to page #100 of this thread you'll still be able to find where the respective posts are. 

 

Scratchbuilding a Heinkel 111 bomb bay - part 8

 

How to build a bomb cell - the improved method. Thanks to Heavens Eagle (Paul) for the idea to not make a part with four walls in one but to split it (I won't split it in 2 but in 4), this gives a number of improvements:

 

- The punch & die needs not die. 

- No folding necessary, thus maximum chance it will fit. Alignment should not be too much of a problem. 

- In case of a tiny mistake, only 25% is lost, compared to the earlier method. 

- Painting will be easier. 

- No need to bend the parts while painting, no need to build a jig. 

- Each part can be detailed externally before painting. 

- Painting of each interior side can be done individually. 

- Easier fitting the square horizontal interior parts. 

- Less chance to unintentionally bend areas of the part that I'm not currently working on.

 

And probably more. 

 

After that thought I got another thought, regarding the cutting out of the octagonal hole. Using a jigsaw doesn't work. Using a file bends it and isn't too accurate. Cutting it with a knife leaves a curve in the sheet. Scribing it endlessly is just bound to fail because of inaccuracy and it will always need to be filed afterward. Pushing with a knife simply bends the whole thing. Bending it to/forth/to/forth 50 times sometimes work but bends the rest of the sheet slightly. And probably I tried more tools and methods but they all didn't work. Yesterday I found a very workable solution, at least for my purposes. Now that I know it, I'll use it more often. As with many things it's simple but you just have to get the idea before it's simple :-) Together with an idea by my girlfriend it makes an easy and effective method. I'll describe it below. 

 

So, my second attempt to write a step plan, this time for the template part. 

 

1. 

First, do all the measurements. You'll be pleased to see the hereunder drawing where I did this for you. This should be at least 95% accurate and hopefully more (relatively). Absolutely, I started with the eduard base measurement. As Eduard's wall parts are each 13.75 mm. wide AND they seem to fit perfectly in the Revell model (also taken into account the space for wing spars and the cartridge locker which was at the right bulkhead side in a corner (lost on all planes that survived but luckily photographed very well and to be seen in manuals)) AND the height seems to come very close to the real deal, my conclusion is that I won't be very far off. 

 

In the hereunder drawing all measurements are in mm. The drawing is 2:1, so twice as large as the part to be built. In most cases there are two mm numbers. One for the part, below between brackets the measurement for the plan. 

 

 

If you want to showcase the bomb cell outside of the plane then below the side wall parts (the one with the octagonal holes) extra horizontal strips have to be made. The measurements of that strip are:

 

- Strip measures 1.69mm x 13,75mm.

- 4 holes for the screws to attach to the plane. From left to right, the length between the holes: 0.88mm, 4.0mm., 4.0mm., 4.0mm., 0.88mm. All on the center line. 

- Each hole is measured to be, on scale, 0.34mm in diameter. I used a 0.3mm drill and after making the hole held the drill sideways very slightly while making a circle. Should be about right now. 

 

2.

Take a 0.005 mm. sheet. Yes I chose a thicker one again. It seems that this handles better and a bit of comparing made me realize that it's actually scale-true (the metal of the bomb cells was quite thick). Make sure you have a 90 degrees corner as the position from which to work. Brass sheet doesn't always come nicely cut 90 degrees so maybe you'll have to cut off a bit. From the left side make two scratches with the measuring tool @ 13.75mm, near the top and near the bottom. Position a metal ruler in the right place (check by slipping the point of a hobby knife in both pre-made cuts and trying to move the ruler toward the knife. Doesn't work? Then you have a perfect position. Now hold the ruler tight to the part and scribe. Scribe once more. With a Hold & Fold and two grip bits (two small rulers should do), fold back-forth-back-forth the piece and it will come off neatly. Now mark 56.12 mm. from the bottom (remember what that side of the part is!) left and right. Repeat the marking/folding/snapping off-procedure. 

 

 

3. 

Make vertical and horizontal lines with a knife. Not too deep. Measured from the bottom of the piece, the lines should be at 18.96mm, 20.43mm, 38.08mm, 40.41mm, 43.51mm (=future fold line) and 45.16mm. Do likewise with the vertical lines. See drawing for measurements. Of course it's better to measure from both the left side (left scribes) and right side (right scribes) to ensure symmetry. 

 

 

4.

With a scratch pen, make markings near the corners of the lines to be torn off. AND mark a hole where you want a 'cutting point' to be. Then with a 8mm drill, drill the holes. 

 

Each cutoff shall be done through folding to-forth-to-forth. So every line to be cut off has to be individualized. Each individual residu part will be folded to-forth-to-forth etc. until it snaps off. To be able to do that, you'll have to create foldable 'borders'. I think of them as the white borders of cardboard houses everyone has made in their youth. There they were meant to glue the different parts together. Now they are used to provide grip to shimmy off the part. Pff difficult to explain in words. Let's see some pictures:

 

The holes near the corners:

 

5.

Connecting the holes with a sharp hobby knife. Now three 'borders' have come into existence. 

 

 

Thanks to my girlfriend for the drilling idea. Important step: after drilling, take out the drill bit and use it as a saw, to reach the end of the corner. That way when snapped off, the part won't leave residue flash. If you drill too far toward the corner you'll run a chance of ruining the piece. 

 

6.

Here you can see the folding taken place. Note that on this picture I hadn't 'sawn' the right drill hole to the corner yet. 

 

 

7.

Mark the octagonal hole diagonals (use measurements of the plan, 1st picture). Use the same method as before. 

 

 

8.

Here you can see 10 drilled holes and 9 cuts to connect the holes. This creates 8 'borders'. Now is a good time to scribe the cut lines once more. 

 

 

9.

Use the Hold & Fold (what a machine... so many uses) and just fold to-forth-to-forth each 'border' until it simply snaps off. Repeat this with every single part. With the bow-tie part I didn't do it for the smaller 'borders' as they snapped off easily. Unfortunately one of the diagonals of the bow-tie piece didn't snap off along the correct line so I'll have to make that one again. When I'll do that I will use the Hold & Fold for each 'border' just to be sure. 

 

 

10.

Cut off everything. The result (which already is very satisfactory for me but could have been better if it weren't for the drill holes that can be seen in some corners; hence the 'sawing' with the drill bit): 

 

 

An advantage of this method is that making the piece is considerably easier than when following the previous step plan AND it takes considerably less time too. AND it is much more fun. 

 

Time spent building, planning, drawing plans: 73H. Studying: 43H.

Edited March 15, 2014 by Roy vd M.

[Roy vd M.]

And another advantage of the "Heavens Eagle-method" is that it simply saves me money, because I'll get more bomb cells out of one sheet. 

[Roy vd M.]

Paul, maybe you shouldn't write off he Eduard bomb bay. 

 

After having taken a look at this incredible post of yours: http://forum.largescaleplanes.com/index.php?showtopic=44240&p=461726 I'm going to have to take these words back. Yes you probably ARE going to build the 111 bomb bay from scratch   

[Heavens Eagle]

LOL!  Hey Roy!

I only am considering making the bomb cells from scratch after looking at your photos.  The large 8 sided holes in the sides of the Eduard PE parts are WAY too large, plus there is the reinforcements on the sides that are not part of the Eduard parts.  Eduard does a very good job for the most part but once in a while they just miss the mark.

 

I personally don't like the self adhesive PE they put out.  The adhesive is gooey and this type of "stick-um" loses it's grip over time.  In additionif you need to bend a part that has the glue, it can be a problem.  On the Ju 88 I am building (sorry no posts yet, but lots of photos taken)  The instrument panel has a bend on the lower left side.  With the glue this is a problem to deal with.  I figured out that the glue can be carefully scraped off and a gentle wipe with a "DAMP" swab with a little paint thinner to get the residue off.  Too much and you could possibly damage the printing on the front.

 

Oh, while on front panel PE, they show just putting the front piece on top of the back instrument faces part.  Looks OK that way but thought something was missing.  Had some very thin clear sheet and put it between the 2 parts and WOW!  It gave the glass reflection over the dials AND some depth to the instruments.  Made a BIG difference with the look.  To adjust for all that thickness just thin the plastic panel part a lot and it will be fine.

 

THanks for your nice comment on the Seimens Schuckert Roy!  That kit just got put to the side a I was working on another (Really POOR) kit and is still boxed away from my move.

 

Thanks for the drawing!  I will make a nice CAD version soon and send you a copy to use.  Glad that my suggestion was helpful.  It just seemed that you were making it harder on yourself than it needed to be and wanted to help.