Fokker Dr.I by Torbogdan - FINISHED - Model Airways

[Torbogdan]

On 2017-04-02 at 8:10 AM, Nirvana said:

Tor,

A good morning to you.....

This is something I think we all have experience from time to time with MS products..... the close shortness of one item or two.

Hopefully you don't have to run out and getting replacement.

 

Forgot to mention, send me a 3 1/2 as it is more than two years ago I had one.

If US customs will let a beer can through, no problem!

[Torbogdan]

The tail assembly has been glued into place! And although it is difficult to see the tail skid has also been fitted. I started on the machine-guns a few days ago. It is a much later step but there was not much else I could work an a few days ago as I was waiting for glue to set and time to get the nylon thread to replace what was "missing" from the kit. Now I have 220 yards of grey nylon thread thanks to the local supermarket...

 

 

The tail assembly in place! It is difficult when large subassemblies are put together as all the small little mistakes made earlier "gets multiplied" and things are/look out of joint or not perfect matches. All angles that were 89 degrees instead of 90 suddenly gets noticeable as all small mistakes are "added" together. But all in all, it looks good, I think!

 

On the tail skid a bit of bungee cord is not yet added. The cord in the kit was a bit too thick, I´ll replace it with thinner black thread/rubber band.

 

 

The Spandaus, quite "iconic" German MG from WWI. The casting is not such good quality. I´m spoiled by crisp resin and hard plastic model kits so soft Britannia metal does not impress me (it can only be matched by my inability to take sharp pictures...). I have added some putty as there was large gaps between the pieces. This will of course be sand papered. A lot would have been won if the cooling mantlet had been made in photoetch I think. The MG:s will of course get some more work done on them, painting and such.

[CDW]

Gas Patch models make a beautiful set of 1:16 Spandau guns, but they are pricey.

 

https://www.bnamodelworld.com/for-other-scales-model-planes-gaspatch-models-gas15-16079?zenid=d1f49320612eb0ea8862234ad9690013

 

Regards

CDW

[vossiewulf]

Having scratchbuilt quite a few Spandaus including this scale, the accuracy of the Gas Patch version is quite good, only part that looks a little heavy and simplified is the ammo feed. Otherwise looks quite good for a mid-late production LMG08/15 version. 

 

Like all Maxims, it ejected the rounds forward from the lower receiver under the barrel. The long box on the left side is the fusee spring that controlled recoil, the little gauge in the middle is where you set it; back then it helped to have an easily adjustable spring to handle the greater variability of ammo. Can't remember what the top and min values where but it's set in the typical place, about 250 rpm. They were called Spandaus btw as many were made at the national Spandau arsenal and those have the city/arsenal name stamped on the top of the receiver. 

 

Also the cone on the end of the barrel isn't a flash suppressor, it's a muzzle booster to provide a bit more backward recoil energy, the WWII MG34 and MG42 had something almost identical. The Parabellum machine gun that observers used was also a Spandau/Maxim variant, just further lightened for ease of gunner handling and the internal mechanisms were lightened to provide the higher ROF a gunner needs compared to the fixed forward-firing Spandaus.

[vossiewulf]

3 hours ago, Torbogdan said:

The Spandaus, quite "iconic" German MG from WWI. The casting is not such good quality. I´m spoiled by crisp resin and hard plastic model kits so soft Britannia metal does not impress me (it can only be matched by my inability to take sharp pictures...). I have added some putty as there was large gaps between the pieces. This will of course be sand papered. A lot would have been won if the cooling mantlet had been made in photoetch I think. The MG:s will of course get some more work done on them, painting and such.

Yeah, I wouldn't use those, this is where I have a problem with Model Expo aircraft and cannon kits - their insistence on using white metal where it's totally inappropriate. I took forever to do one of the cannon kits because it took many hours to file, sand, fill, and rescribe detail. I recommend either buying the Gas Patch versions or making your own, but as you see they had lots of complicated bits sticking out the right hand side and you either need to simplify those bits or be prepared to spend a few hours scratchbuilding accurate versions, if you do the latter use styrene sheet/plasticard.

[vossiewulf]

If you don't want to total scratchbuild, you HAVE to replace the cooling jackets, they are iconic with respect to German aircraft of WWI and anyone who knows the subject at all knows what they should look like.

 

Here's a mid-road to take - these are the people I use to do custom photoetch as their costs are extremely reasonable and they'll work with you to get it right. In fact I used them for the exact purpose of creating Spandau cooling jackets, unfortunately in 1/12 which doesn't sound like much but it'd be obviously too big for your plane, or I'd send some that I still have. However I think I still have the artwork and if so it's a trivial matter to rescale it. They need vector artwork, one can do it in Photoshop where they are called paths, or Illustrator, which is designed from the get-go to do vector artwork but I find Photoshop easier to learn if you're not familiar with the process.

 

But in this case you wouldn't need to learn that bit if I can find the artwork. They have a minimum size so you won't get just two, I think I had 10 or 12 in the sheet they made for me. If you went with the smallest sheet size you'd be around 50 pounds shipped... maybe 60, or about the cost of one of the Gas Patch guns.

 

That said, unless you prefer to make the Spandau bodies with their exposed gizmology yourself, it would be a much better idea to use the Gas Patch guns if you can afford it.

[Torbogdan]

I have decided to buy the Gaspatch guns. The ones in the kit are not to my liking, missing way too much detail. For me a fighter aircraft "is its guns". If it doesnt have nice looking guns what use is the model😉? 

 

 

[amateur]

That will make a major difference to your model!

Problem is: now you will be tempted to replace other white-metal parts as well....  

 

Jan

[Torbogdan]

You are very correct. I would seriously consider a new engine and some controls and levers in the cockpit. 

[CDW]

With the great job you've done on the airframe, the attention to the guns will be a welcome addition. Good choice.

[CDW]

That radial engine would not be a terribly difficult one to scratch build if you are inclined to that sort of solution. It could end up a much more suitable end product that the kit supplied engine. Perhaps there are parts of the kit engine you can use, just detail a bit. There are many sources of detailed drawings of the engine on line, just need to scale it to your needs.

[vossiewulf]

Scratchbuilding the engine is considerably more difficult than the guns. I of course when the very hard road because some reason I don't know, and did it in aluminum. Even doing it in simpler materials is not easy and you'll need to be reasonably good at casting. I'll post some more info later.

[xken]

I may be a little late, but here are some steps on how I made the earlier version of the guns. Also not sure if Tom's Modelworks is still in business. I did scratch build my own cooling jackets when I did my Triplane. Just FYI 

 

[Canute]

Tom,s is still in business. Different owner.

[xken]

Ken, Thanks here is the set I used. http://www.tomsmodelworks.com/catalog/product_info.php?cPath=22_32&products_id=30

Will be buying now that they are available again.

[vossiewulf]

2 hours ago, Canute said:

Tom,s is still in business. Different owner.

Tom passed away like 20 years ago now isn't it? If they're still carrying 1/16th Spandau jackets, those are based on the ones he made for me, I had him make 1/16th jackets back in 1992 or 1993 when the largest he made was 1/32 and I was the first person to request 1/16th from him. VERY nice guy, spent considerable time on the phone with me working through a couple prototypes before we got it right.

 

I was very saddened to hear when he passed away, he was a very cool guy with big ideas, he would have remained a real presence in several hobbies.

 

As I was saying, spinning out an accurate Le Rhone 9b/Oberursel UR.II is not exactly child's play, and if done in the standard manner of casting the cylinders split along the long axis, it can lead to the loss of will to live as you try to level and sand out the glue joints from eleventy hundred cooling fin joints. 

 

That plus the challenge led me to machine them, these are for a 1/16 Camel that is currently on hold, I need to swing back to my WWI stuff at some point. The cooling fins are .006" and I had to make a custom cutting tool similar to a parting tool and you can assume there were a couple of spectacularly exploded prototypes before I got one that would hold together. I used a DRO for depth and a dial indicator stuck with a magnet onto my lathe bed for the fin spacing. 

 

It was slow careful fiddly work where I pretty much held my breath the whole time as I was operating beyond the hairy edge of what the mini-lathe, and 2024 aluminum as a whole for that matter, could handle and had several explode or jam the machine, will train you to be fast on the emergency stop if nothing else.

 

 

Engine block/casing/prop shaft/rear prop mount were machined out of a single piece of aluminum on the lathe first, then taken to milling machine where I used a rotary table to machine the 9 flats, drill the cylinder mountings, and the holes around the ring on the front of the casing and the prop mounting holes.

 

If you know how to cast resin reasonably well or know someone who does, I could send the engine and one of the cylinders to you, let me know.

 

[xken]

Vossiewulf, if you have a milling machine and a rotary table an easier way is to use a slitting saw to cut the fins. Still requires attention to detail but much less nerve wracking. Are you familiar with the model engineering show up in your area?

[Lucius Molchany]

Hey Wulf,it would be really cool to thread the ends of the cylinders so that they would screw into the engine block.Heck of a challenge to your machinng skills!

[vossiewulf]

2 hours ago, xken said:

Vossiewulf, if you have a milling machine and a rotary table an easier way is to use a slitting saw to cut the fins. Still requires attention to detail but much less nerve wracking. Are you familiar with the model engineering show up in your area?

Where the hell were you when I was making these?  OTOH then you lose the excitement of cutting one of those grooves in one pass when you can feel the piece pulsing, with each pulse just infinitesimally short of the point at which the cutter grabs and then there are loud noises and lathes bouncing around a workbench and mass hysteria, gets the blood flowing. Sometimes literally.

 

I'm familiar with the Makers Faire, not sure if that's what you mean.

 

6 hours ago, philo426 said:

Hey Wulf,it would be really cool to thread the ends of the cylinders so that they would screw into the engine block.Heck of a challenge to your machinng skills!

I considered that and decided yeah I think I'll go with an internal steel dowel pin for alignment ;-)

[thibaultron]

For the less machine tool gifted, how about stacked disks, alternating large and small dia.?

[Lucius Molchany]

Yep that would work well too as long as the fit is good to ensure proper alignment of the cylinders.

[xken]

Wulf, here is a link to the show. Put this on your must go to list, plenty to see, swap meet and suppliers to buy from. Plan on taking a fair amount of cash. 

 

http://www.wemeshow.com/

 

 

Ron, the challenge with stacked disks is cutting them out and then alignment. This was one reason I bought my first lathe. As for casting in resin one would need to do pressure pot casting to drive the resin into the fin detail and then contending with the cleanup of the mold joint lines. Don't ask how I know all this. 

[vossiewulf]

16 hours ago, philo426 said:

Yep that would work well too as long as the fit is good to ensure proper alignment of the cylinders.

Work yes, "well" is a relative term. For Le Rhone cylinders like mine, you'd need 56 disks in 6 diameters (one the inner diameter, other five outer diameter including the tapered width section at the bottom of each cylinder). Times 9 cylinders is 496 disks.

 

So let's say you just focus on the two main diameters, you'd need to turn two cylinders of the appropriate diameter. Then you drill and ream out the center, because you need an exact fit and also to minimize the amount of material to be cut to part off each disk. And the parting off process has to create disks of equal thickness down to a couple ten thousandths of an inch. That's harder than what I did.

 

So a better route would be to part off perfect thickness pieces of each diameter, and then create a fully enclosed RTV mold and then make say 12 of each, and then make new molds that will cast 12 of each at a time. And then you'd need to cast 41 sets of 12 each.

 

Then you'd need to glue 496 pieces. I think you're getting the point <g>, I thought about this too and decided although in some ways it wasn't as hard to do it that way, doing it that way would actually require far more time and effort than just turning them on the lathe.

 

The one thing I didn't try that may have promise is to get RTV that's as flexible as possible, and then instead of making a two-part mold that results in a mold seam on the cooling fins requiring many many hours to remove, cast them in a one-piece mold and hope it's flexible enough to demold each part without tearing the mold or breaking the resin fins. If that would work, you'd need to machine only one good example of the cylinder and then cast the rest, with almost no clean up processing required.

 

If someone wants to try that, let me know and I'll send one of my cylinders to try, but you also have to promise not to damage my parts as I really really really don't want to have to make replacements that match.

 

13 hours ago, xken said:

Wulf, here is a link to the show. Put this on your must go to list, plenty to see, swap meet and suppliers to buy from. Plan on taking a fair amount of cash. 

 

http://www.wemeshow.com/

 

 

Ron, the challenge with stacked disks is cutting them out and then alignment. This was one reason I bought my first lathe. As for casting in resin one would need to do pressure pot casting to drive the resin into the fin detail and then contending with the cleanup of the mold joint lines. Don't ask how I know all this. 

Thanks Ken, it's on the schedule now

 

BTW name is Jay and that obviously works, but if you use my handle it's Vossie, not Wulf. I answer fine to Vossie, I've had this handle since 1991 on CIS and GEnie and even (ex) wives have frequently called me that.

[Torbogdan]

Due to a heavy workload during the last days I have not had time to "follow" my own thread. Hope to be back in about a week. 

[Nirvana]

We others will be around awaiting an update whenever you have one.

[Torbogdan]

 

The next step according to the instructions! I guess this is the equivalent to rigging a ship model

 

It is very nice to read all the different posts here. I learn a lot about WWI planes in general and the Fokker in particular and specifics, such as machine-guns and constructing rotary engines in 1/16 scale

[vossiewulf]

Torbogdan, use lighter wire than that shown for the internal bracing, that is much too heavy and will annoy you over time.

 

Trying to find a good Dr.I pic but here is a repro D.VII, same wire and turbuckles and steel tube and little quarter circle gusset/connectors used on both.

 

Adding this one, this was the one displayed in some agricultural museum in England during the war. You can just barely see the control cables and the bracing is there but almost invisible at this distance.

 

 

[Torbogdan]

@vossiewulf, nice pictures. Thanks. I´m using a thinner thread for the rest of the wiring compared with the one in the kit. Looking back I would have used a even thinner one but to change now would look strange, because the internal bracing is made up of the "thick" string supplied in the kit. If the the rest of the bracing was done in a very much noticeable wiring it would look strange I think.

 

But still, scale wise the wiring is too thick. My next model (already planning one...) I thinking of using very thin fishing thread. Being translucent and thin I think it will give a good impression of thin, thin wire.

[vossiewulf]

You should check with the guys working in 1/32 or 1/24, chances are they will have some heavy rigging wire that would be the right size for 1/16. You should definitely look at what Uschi has available, look at the leather decals and the metal powders at least.

 

Also here's some good general rigging info on WWI aircraft/models. Remember that rigging wire of the time was solid steel, not braided, so best material at your scale might be fine piano/hard wire, and you should be using a fine enough wire that bending and twisting shouldn't be a major issue. I don't think they have any British aircraft so you don't need to worry about British streamlined wire.

[Torbogdan]

 

I´ve started on the internal rigging for the fuselage bracing. I know it is a bit on the "heavy" side but after trying out a few different techniques and wires this is what is the best compromise between size and "time spent". A thin thin metal wire would look nice but after trying it out it took a lot longer time than using thread. There are quite a few wires and if each wire takes 15 minutes longer ( for example) and there is about thirty wires... Well that is a few hours of extra work. 

 

I´m torn between detailing and ( in the end ) finishing. It is easy for projects to bog down if you spend too much time "just adding that final touch" on each and every detail, in the end the model does not get finished or at least not in a reasonable time. So I try to stop myself from falling in that "trap". 

 

I try to choose a middle ground

 

In an early step I used the kit provided thread for the internal bracing. If I had changed to a much thinner thread it would have looked a bit weird. This was before I was made aware of the Uschi website. I would have liked to use their stretchable rigging but it was a bit too late to redo everything. I´ll keep it in mind for my next aircraft model.