1/72 Zeppelin-Lindau (Dornier) Rs II scratch build

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2 years 6 months ago #161 by Stevef
Evening All,

FYO another modeller has described this as "scaffolding with wings" which I thought was rather appropriate. Another has called it my Pokemon!

On to the build: I have still to work out precisely how the wing is going to be fitted as I am trying to think of a jig which will not be more complicated than the model...............

I am also concerned about the strength of the cabane struts, which as shown earlier I have reinforced with brass rod, but still cannot make up my mind whether to reinforce some of the V struts. The problem with the latter would be how to fix them to the attachment points on the hull because if I do it would require drilling holes at awkward angles in a very small piece of plastic. The V struts are also long and inserting rod and keeping the strut even would not be simple. I have a feeling that I am going to just use thick wide strip and hope it works: if it does not.....dammit it will!!!

Before the wing can be fitted however I had to put on the radiators above the engines. They were scraped and shaped from plastic card with grilles scribed with a sharp knife. The filler caps were from two thicknesses of rod. The bracing, supports and radiator pipes were also rod.









I have tested the cabane struts again as part of the planning for placing the top wing: I keep having different ideas about how to do this and none of them seem to be practical. This is what the struts look like minus the wing:





You can see in these photos that there is not a great deal of attachment between the tops of those struts and a large and heavy wing. Araldite will be the bonding of choice because it will give me wriggle time but will be strong. The question is still how to fix the struts and the wing in a single operation.... I need some form of jig but not one which is too complicated: I think that I may have one and hope to be able to report in the next few days. If I do not then you can reasonably assume that it did not work and I may be on the way to giving up on this one for a time because there is a real risk of damaging the engine installations and radiators which are a bit precarious up there.

More in due course I hope.

Stevef.

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2 years 6 months ago #162 by Stevef
Evening All,

Once again this is in two parts because of the number of images. Photobucket is also playing up tonight so the images are a little odd, but they are here.

I have managed to solve some tricky problems on builds in the past, but I have also learned (and forgotten!) that the more I think and worry about a problem, the more difficult I imagine it will be....... Then when I actually bite the bullet, it is not nearly half as difficult as I imagine. This was so in this case.

Yes gentlemen I have managed to fix the top wing into place ........... at the third attempt! I will not distract you with too many details but just a few notes to anyone else who wants to attempt this sort of thing in future, here were my mistakes:

Attempt 1. I measured the struts and shortened the tops by a couple of mm: this was intentional as I have found from experience that trying to cut pieces such as these directly from plans is a recipe for failure as there are always tiny discrepancies on models (or at least there are on mine). Having cut the struts so that the front pair joined at the top I proceeded to apply the araldite, put the lower ends of the struts into the holes in the hull and put araldite into the holes on the underside of the wing. The wing was placed upside down on a sheet of expanded styrene so that I could clearly see the top ends of the struts, and I gently lowered the inverted hull assembly on to the wing, easing the struts into the holes. The rear of the booms were rested on a support on the styrene. This is the jig support:



And here is the model inverted and supported on the support:





In the meantime I checked for alignment using a large set square that I used to use for drawing maps: this made sure that the wing leading edge was at 90 degrees to the thrust line of the hull. All was left overnight to set and in the morning I found that the wing was not level - ie it was about 1cm down on one side and the same amount up on the other! It took about 10 minutes to find out why: the N strut junction on the port (left side) was not sitting as it should. I had not shortened the angled strut enough and so it was holding up the wing at that point, and because the wing is so big, the distortion was magnified at the tips.

Attempt 2. By carefully cutting and prising the offending araldite joint with a new scalpel blade I was able to release the wing from the struts, and then using the same procedure I was able to extract the strut from the hole in the hull. This took about 15 minutes of nerve stretching activity but I managed it without damaging the other joints. The strut was shortened and re-inserted, again with some difficulty, and the model put back on to the jig and left to dry out. Next day I checked again and this time I found that the wing was misaligned so that the leading edge was not at 90 degrees to the thrust line - I had forgotten to put a support in to stop distortion while the new joint dried out!

Attempt 3. This time I dismantled the whole of the struts assembly - not intentionally but by degrees as I tried unsuccessfully to correct the misalignment by juggling with different positions of struts. It was easier in the end to start again, cleaning out all of the old araldite from the holes in the wing, scraping a tiny bit more from a couple of struts and re-assembling the structure. This time I intended to make sure that horizontal alignment would be correct AND that the wing leading edge would also be at the correct angle. This meant that the wing had to be on top this time so that I could hold the hull and wing at the correct angles. I abandoned the styrene jig and used other materials instead viz a pile of books, a paint pot, graph paper and a pair of my late mother's hair grips.







More to follow.

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2 years 6 months ago #163 by Stevef
Evening all,

Here is the remainder of this post:

This time it worked! I know that some of you write/talk about kits "fighting you" - this is not a kit but I certainly have had a battle with this particular assembly. I have checked both the alignment of the wing to hull - correct, and the height of the wing tips from the desk top - there is about a 2mm discrepancy and as I cannot see it by eye I can live with it. So here is the model as of this evening, ready for me to start putting the large under-wing V struts into place. I am breathing normally again and I think that I should be able to complete this before the January deadline, provided that I do not drop it or run into another unforseen problem.







Thanks for looking.

Stevef.

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2 years 6 months ago #164 by Stevef
Evening All,

I am aware that time is pressing and that I will be away for part of the holiday break - specifically New Year so I want if possible to have this finished before I go because I will not then be thinking about it all the time. Of course there is still plenty of time for me to make more mistakes, as I found out today - details to follow, and I do need to allow some time for the possibilities of these happening again! The deadline for the GB is 7th January 2018.

I had cut the underwing V struts from 40 x 120 thou Evergreen strip - 2 pairs per side - and scraped and shaped them into aerofoil section a little while ago. I had also painted them and drilled holes to take the angled braces between the struts and the upper V and the wing. I also drilled two holes on the upper side of the lower struts to take a pair of generators later. I had measured the lengths from the plans and thought that I had allowed a little extra for trimming to the actual required size.



In fact I had not! Do not ask how....... as stated in an earlier post if you need advice on how to get things wrong, just ask me! The struts on the port (left) side were just 1mm too long, but on the starboard (right) side they were 2.5mm too short! So I proceeded to put the port side struts on and am in the process of making new longer ones for upper V the right side: I have cut down the existing longer ones to make new short ones if that makes sense! Fitting them was much easier than I anticipated. The photos show that I had already cut the ends which will attach to the small lugs on the sides of the hull and it was a simple job to just file the last few microns to be able to get a near perfect fit. The the top of the lower V and bottom of the upper V ends were filed flat where they are attached to the hull to remove the paint and improve the junction between the pairs as the originals seem to have been welded together. The ends which attach to the wing had also been filed so that they would fit snugly into the slots which I had drilled and cut to receive them. I glued the upper pair at the V joint first, and when this had dried for about 15 minutes I made the final adjustment to length and glued it into place. The lower V was fitted in the same way. Finally I measured the gaps between the struts on the model using dividers and cut lengths of 40 thou rod to make up the bracing both between the struts and the struts and the wing: the ends of the rod were fixed into the holes in the wing and struts which had been made earlier.







The jig that I had prepared earlier to support the model while I put the wing on came into its own for this operation, and I shall use it again when I attach the remaining struts and add the rigging in this area. And before anyone asks what ids the hole doing in the hull, it was not a drain on the original aircraft! This is a large model for me and I therefore intend to display it on a covered base: I want to try to represent the turntable outside the hangar at Seemoos where the machine was built which can be seen in the photographs referred to at the start of this thread, and I have had suggestions from two people that I should motorise the turntable! I have bought a railway turntable motor and the hole in the hull was drilled to take the drive shaft from the motor. I will start a new thread to describe this when I start to make the base in January, and will post it in the relevant section.

Thanks for looking..

Stevef.

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2 years 6 months ago #165 by Stevef
Evening All,

Once again this is a two-parter because of the number of images which I am posting.

Time has been pressing because while we have about 10 days to go on the calendar for the GB of which this model is part, I do not have 10 days at home between now and January 7th so I have been spending as much time as possible trying to get this one done.....and I have succeeded as the following will I hope show.


First I completed the large under wing struts and bracing on the port (left) side, having made a new pair of longer struts for the purpose.





This meant that I could now rig both sides and I decided that this would be a good time to finish rigging the boom too.







I have been making the propellors on and off during the build, and I had made the spinners at the same time as the cockpit screen, so it was time to put these together:



I realised that the propellors needed backing discs - easily sorted by marking out circles of the correct diameter with a pair of dividers on a sheet of 30 thou card and then cutting the circles out and finishing them with a file. These were glued to the backs of the spinners and any small gaps filled and the result painted again:



These were not fitted until the rest of the model was nearly finished. Next up were the small generators on the V struts: small pieces of 60 thou rod were shaped and propellors made from 10 thou card. Two small legs from 20 thou rod were added so that they could be secured to the struts. The aileron horns were cut from 20 thou card and shaped with round and flat files and glasspaper, and then painted. I have started to add them to the port (left) aileron in this image. The small pieces in the middle are the generators:



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2 years 6 months ago #166 by Stevef
With the ailerons ready I inserted three small pieces of wire in holes which I had drilled into the leading edges of each aileron: the wires were held with CA. The other ends of the wires could then be inserted into holes in the trailing edges of the wing and also held with CA, and the control wires added to the horns. With the rigging finished it was time to go for the finish.... the propellors were added one at a time, again using wire to hold them in place in the nacelles. Two clear windscreens were shaped from some acatate sheet which was part of an old bubble pack from an Airfix kit from years ago - also CA'd into place. Last but not least I had to cut lengths of 30 thou plastic rod to add to the elevator sub-assembly so that this could be attached to the rear ends of the tail boom and the model is finished.





I am sorry about the quality of the photos but the light at the moment leaves a great deal to be desired and the weather is not suitable for taking this rather delicate model outside! I will post more photos in the gallery soon.

Thanks for looking.

Stevef.

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2 years 5 months ago - 2 years 5 months ago #167 by Stevef
Evening All,

Having completed the model I now need somewhere to put it. I do not wish to keep it in a large box in the roof, (why all the effort to scratch build the model if I do that?) and as the aircraft was launched and retrieved from Lake Constance on a trolley on rails, the trolley is an obvious feature to mount the model on. The size of the model is also important - it has a span of approximately 17 inches (42cm), and a length of 14 inches (35cm), which means that it will not fit into the display cabinets in which I usually keep my models. Consequently I have bought a perspex covered base and I want to put in it a small display for the aeroplane. The aircraft model will sit on the carriage on a turntable which was built outside the front of the hangar/workshop at Seemoos on Lake Constance which was an old Zeppelin shed in which Claudius Dornier's early flying boats were built when he was working for Graff Zeppelin. I will include a short section of the ramp along which the flying boats were taken to the lake for launching and retrieval, and part of the hangar floor. The display will be based on photographs taken between mid 1915 and late 1918 and published in Windsock DataFile no 136: Dornier Flying Boats. One set of photographs in particular, taken in May 1917, will be used for some specific details as it is clear that there were changes made between 1915 when the turntable and ramp was built and 1918 when the last of the photographs was taken. I am not trying to make a 100% accurate replica: rather this is simply to set off the model aeroplane in a realistic context. This is the first time that I have attempted anything scenic so it will be a steep learning curve for me and I do not doubt that I will be making mistakes along the way, but as the person who never made a mistake never made anything, here goes.

First here is the base which I bought from Just Bases (I have not included the perspex top):





The dimensions of the display area of the base are 21 inches (53cm) x 13 1/2 inches (33cm) which will be large enough for the model aeroplane to sit in it and leave space to put the perspex cover over without hitting it.

When I told to my brother and our honorable chairman Clive Creer of my intention to mount the aircraft on the turntable, they both asked would the latter be motorised! I have to admit that this was not my original intention, but it happens that the turntable was built on the top of a steep bank, so I investigated the possibility of putting a motor under the scenic base. Careful measurement showed that it would be possible:



This is my working plan for this display: it is 1:1. The square is where the motor will be ie under the turntable. The two arcs on the top left are part of the platform that surrounded the turntable ,and the other lines represent platforms and a shed, steps, hangar workshop floor, etc, all of which have been drawn to scale based on the photographs mentioned. The right side of the display area will be left clear so that I can put some explanatory notes about the aeroplane and setting for viewers. The various notes on the plan are for ideas that I have concerning how I might make this - I may of course change some things as I go along. Having a turntable motor would have an advantage that I had not forseen. The aircraft model is quite heavy as it has a wood hull, brass boom at the rear and a large wing made of laminated 60thou plastic card sheet. If this was to be mounted on a railway trolley it would need something fairly strong to hold it in place. By drilling a hole in the bottom of the hull and inserting the turntable shaft, I would have a hidden strong and stable support while the trolley would be what the viewer would see. I drilled the necessary hole in the underside of the hull when I was making the model, after one model railway turntable kit had been purchased:



Testing of the gear assembly for this kit showed that the gear drive to the vertical shaft, which is plastic, would be too weak and would quickly wear. Given that this motor is not going to be accessible when the base is finished I decided that the gears would be better if they were replaced with something more durable: some of my brother's old Meccano gears were therefore pressed into service. (Well he suggested motorising in the first place so he could help find a solution to a problem that motorisation raised). Here is the unit, showing the gears on the vertical drive shaft and original plastic gears inside the clear perspex box of the motor. You can also see that my brother and I have built a stronger and more stable perspex surround (blue) so that this unit can be screwed to the display base:







Now I have to fix the motor to the base and some wood strips which will have holes drilled into them to hold the ends of dowels which will represent the posts which supported the various platforms.

Thanks for looking.

Stevef
Last Edit: 2 years 5 months ago by Stevef.

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2 years 5 months ago #170 by Stevef
Evening All,

As promised there have already been some changes! After a couple of trials my brother and I decided that the plastic gears in the motor might wear too quickly and as this will not be accessible in any way when complete we decided to buy a second motor and replace all of the gears, inside and out. We also made a new perspex box. I am not showing a photograph of the modified gearing - it looks the same as in plastic except that the gears are now brass. I have been carefully measuring and calculating where the motor should go. There are two important factors to consider:

1. The vertical shaft of the motor must be exactly at the mid-point of the width of the base because the wings of the model will have to fit inside the clear perspex cover;

2. the shaft also has to be in a precise position in relation to the length of the base because the nose and tail of the model have also got to fit under the cover.

When I ordered the base I allowed a couple of inches (approx 5mm) clearance between the extremities of the model and the perspex cover, so there is little room for error. Fortunately the turntable at Seemoos was on the edge of a bank and it happens that the top of the casing of the motor is just about the same as the ground level of the top of the bank. This means that I can cover the motor case with plaster bandage, build the slope in front of the motor, and level the ground at the base of the bank to coincide with the edge of the base frame, and it will be very close to scale. The motor has been screwed to the base. The lines on the board mark where the various platforms will be, and the top and bottom of the bank slope.



The battery holder, switch and wiring are at the back of the image.

Another structural element that has had to be measured and planned is the location of the posts and beams that will support various platforms including the turntable, between the hangar and turntable, slipway and a side platform from the turntable. There was also a platform immediately in front of the hangar. To ensure that the posts will be in the correct positions and stable I decided to drill holes in a wood plank which I found in my garage. I cut it into lengths and drilled the necessary holes and then screwed the wood bases to the display base, and I have made one queen post from dowel and obechi which is visible in this image:



The gap in the front of the base is where I will be putting an information board: the edge of the landscaped section will be marked off by a vertical sheet of plywood.

I have also been experimenting with plaster bandage as I have not used this material before. I wanted to create a bank with a level surface on each side of the bank. I used some scrap expanded polystyrene which I had glued together to create an uneven slope which I then covered with the plaster bandage:





When this had dried out I smeared a layer of plaster filler to fill the holes in the bandage. Finally I used some diluted PVA white glue and scattered some sand over it. This is the result which I think is not bad for a first attempt:





I am thinking of using sheets of expanded polystyrene covered with plaster bandage for the groundwork because it is very light and I have quite a supply of it.

Finally I have been trying to make the turntable and surrounding platform. The turntable consisted of a thick wood planks which seemed to have been fixed to some form of frame, the details of which are unknown to me. In fact just how the turntable was constructed and held in place is also a mystery to me, so I am using modeller's license to make something that will look plausible but also be practical. The circular platform around the turntable also consisted of a series of wooden planks but these were spaced and seem to have been supported by queen posts with horizontal beams between the queen post supports. This would be very difficult to replicate accurately, so instead I intend to cut a ring of plywood and glue wood strips to it. I can cut a turntable base from the disc centre of the plywood ring. I have cut a circle of plywood but am not very happy with the result because I have had real problems with the outer edge and I am not sure how I can get a clean edge inside too.



I am in deep thought about this at the moment and am considering using some other material, perhaps thin basswood sheet.

More mistakes and changes to come!

Stevef

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2 years 5 months ago #171 by Stevef
Evening All,

Here is the next instalment of how I am changing my mind as I go along with this display. I discussed this project with members of the club: they have advised me not to use expanded polystyrene as the ground support but use instead the foam plastic which is used for cavity insulation in modern houses. Steve Noble had some spare and has kindly supplied me with a suitable block: thanks Steve.

The advantages of this material is that it is solid but very light, it is easy to cut and shape with a large sharp knife, will take a plaster covering, will take dowels easily if I drill some small pilot holes first, and is exactly the correct thickness for the bank and upper surface that I want to make. So out came the pieces of wood which I had fortunately only screwed to the base, and in went the foam insulation. I had to cut the foam to fit around the motor and it had to be trimmed to make a bank slope. In addition some thin pieces were placed at the front to bring the ground level up to the edge of the surround, and a small off-cuts were placed in front of the base of the bank and motor to get the correct bank slope. To stop the smaller pieces sliding around they were held with white PVA. I cut two strips of plywood to make the sides: these are rectangular at the moment and only slotted into place. Later they will be cut to match the side profile of the ground and bank. The rear compartment which will be concealed under the hangar floor is now hopefully obvious: that is where the battery holder and switch will be kept. The right side has the off cuts of foam in it at the moment - that is where the descriptive panel will be placed in due course.



This is from the front - the right side has the off cuts of foam. The top of the motor is clearly visible, as are the pieces of foam at the base of the bank - these will be covered with plaster bandage later but are needed to create the correct angle.





From the left and right sides respectively. The cut edge of the foam is clearly visible in these views as are the plywood panels - they are too tall but I need to put on the plaster bandage before I can trace the ground profile on to the wood. Then I can cut the wood to fit exactly. Consequently the wood sides are only slotted into place and can be withdrawn easily. The panels also extend the full depth of the base as they will also form the sides of the battery and switch compartment at the rear of the display.



From the rear: the large space will be under the hangar floor. The rear of the foam will also be supported by plastic sheet with the top above the "ground" at the level of the hangar floor. This will close off the space at the rear of the display.

More changes to come no doubt, but at the moment the next step will be to apply the plaster bandage to create the ground surface.

Stevef.

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2 years 5 months ago #182 by Stevef
Evening All,

I applied plaster bandages to the foam base. I laid them from the rear to the front which meant that they could be easily overlapped: the lengths were short and easy to measure and handle. This was both quicker and easier than I had thought it would be. I took the plywood sides away for this: they were put back before I took the photos. The dowels pieces at the rear will be used for posts later: they were there temporarily. I cut a length of 20 thou plastic sheet to represent the arches which are visible in some of the early photographs of the front of the hangar. I cut some slits into the foam and bandage cover so that I could push the bases of the plastic arches into it. It seems that the arches were to allow access under the hangar floor, but how far under the hangar they extended I have no idea. They will be visible when the wood platform has been constructed in front, so I have allowed for a short section to be represented. The rear will be blocked by a sheet of card which will also hold thef the foam base in place, and I will put in some curved roofs later. The front of the arches has been painted grey to represent concrete(?): the exact colour does not matter because they will be barely visible when the platform in front is finished.





When the bandage was dry I smeared some plaster filler over it in an attempt to seal the holes. This was done pretty crudely because I also wanted to eliminate some of the prominent ridges that resulted from the overlaps. I put the plywood sides back and marked off the ground surface, the vertical edge of the wood platform which will be in front of the hangar, and the level of the hangar floor. The plywood was cut, put back and glued into place. On the right side the base of the plywood was further secured with some short pieces of quadrant: the sides were glued to the foam using superglue. The rear of the plywood forms the sides of the box which will house the battery holder and switch. I painted the ground surface with Revell Mittelgrau (43) acrylic paint - two coats - but even so there are still holes in the plaster bandage which I may have to fill and paint again.

I have also marked and drilled the holes for the platform posts. I used an undersized drill to start the holes and pushed the dowels into place to complete them. I have not put the dowels in permanently yet: there is still more tidying up to do and I have to carefully measure and cut the posts which will form the base of the circular platform first. Some of these will be very short as they will sit directly on the perspex cover for the turntable motor, while others will extend to the base. There is still a lot of measuring and levelling to do before I can begin to place posts in holes permanently.







More details of how well I manage to stop myself from falling off this learning curve will be posted shortly.

Stevef.

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