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Old Apr 14, 2005, 03:17 PM
edi
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Aerodromerc Fokker Dr.1

Hello all,

yesterday I received my aerodromerc kits, a Curtiss Canuck and a Fokker Dr.1.
Well, I guess I'll build the Fokker Dr.1 first. Right now I'm flying a Simprop Dr.1 and a Kavan Sopwith Triplane. Both fit together into my Toyota Prius, but the aerodromerc Dr.1 is rather bigger.

Therefore, I'd like to be able to take the wings off for transport. Nice for repairs, too. Any hints for that? These are my thoughts so far:

The bottom wing could be removable by simply not gluing it in but by holding it in place with a rubber band inside the fuse.

I'm planning to build the middle wing in one piece and make the fuselage holes for the longerons longer so the middle wing can be put onto the fuselage much the same way as the bottom wing.

I'm unsure about the cabane of the upper wing and the UC.

The struts: I'm considering to put ply ribs next to them protruding on the upper side (bottom wing) or the bottom side of the wing (upper wing). Then a hole drilled through these ribs and the struts would allow securing the wings with a dowel and removing it the same way.

The powerplant is my other issue: I'm used to quite a lot of power for emergency situations. My Tripe (400g) has a kontronik dancer and the Simprop Dr.1 (360g) a yellow-bl. Sometimes during the landing I get a gush of wind lifting the plane another 2-3 feet just before it touches the ground. For my lite-stick and my Fokker E-III (Lenger), although adequately powered otherwise, this resulted in several very hard landings. My two triplanes on the other hand, can easily recover by simply pushing the accelerator to full power pulling them up almost vertically. I'm rather used to this possibility, and for scale-like cruising I can always throttle back.
What powerplant would you recommend for this? I'm considering a brushless Graupner Compact 480 (a new outrunner designed for models 28-55oz and about 13x8 prop). I'm planning to use LiPoly batteries (I'm not using anything else) and such an outrunner might help to get the CG in position.
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Old Apr 14, 2005, 03:27 PM
edi
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A few words about the kit:

The CNC parts make an extremely nice first impression. The kit contains the two sheets of the plan, three sheets of pre-cut plywood and nine sheets of balsa. The shipping method of putting several kits into one box for shipping saves money. Kudos to you, and some more kudos for your extremely fast shipping (took exactly 7 days to Germany, incl. customs!)

The only thing I'd like to see added is a list of parts for which no material is supplied - that would make shopping easier.
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Old Apr 14, 2005, 04:10 PM
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I am working on those needed materials lists and have this one finished.

Fokker DR1 parts needed to finish
Qty Item
3 1/4 sq. x36 Balsa
6 1/8x3/8 x36 Bass or Spruce spars
6 1/8 Sq. x 24 balsa
2 1/16 Music wire 36
1 12x6 x1/32" birch plywood grain running short way
1 1/8x1/4 x 36 bass or spruce
1 1/8x3/16 x 36 bass or spruce
1 3/8x1/4x18 balsa
1 1/8x1/16 x 36 balsa
1 1/16 sheet balsa 4x6
1 1/8 dia. Birch dowel 6 long
1 3/32 OD Brass tubing x12"

Kurt
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Old Apr 14, 2005, 04:59 PM
edi
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I've done the shopping earlier today, but thanks anyway. What do you think about the changes I have in mind? And one more silly question: What is bass?
Didn't find it in my dictionary.

I've also asked my LMS about the covering, especially about oralite since they are an oracover reseller. I was told that it's not really worth while on the grounds that the gain is marginal and requires very careful appliance of Balsaloc. Hmmm. Would standard oracover be ok?
I still have a few sheets of litespan I brought along from England a few years ago and the instruction sheet says it weighs about 30g/m^2 as opposed to 92g/m^2. I guess I'll need about 1.5m^2 of covering so that would be a gain of almost 100g, wouldn't it? Of course, I have to apply the glue (Graupner Ecofix is what I've got), but how much will I have to put on the whole plane to cover it? 50g?

I guess I can still save about 5% of the final weight by using litespan instead of oracover, but will that be worth the hassle?
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Old Apr 14, 2005, 05:12 PM
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I think that the modifiations for making the wings removable will be quite a lot of labor and for a wingspan of 35", not much savings. Still if you enjoy that sort of re-engineering, then I say go for it.

Bass or Basswood is a straight grain yellow wood that is a bit heavier than balsa but much stronger. Spruce can be substituted.
Covering is such a personal thing, I prefer Litespan or Polyspan and not the plastic coverings. They look so much more like the linen used at the time. They are very low in weight. BTW, Polyspan is made in Germany.

Kurt
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Old Apr 16, 2005, 03:02 PM
edi
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middle wing

Well, finally I've started. Kurt, I was so impressed by your magnetic building-board I decided I want to have one. So that was the first task today.
I thought I would start off with the middle wing. I didn't get basswood and no spruce of exactly the right size so I used 10x3mm spruce.
You can see it roughly sanded now. The build was easy and straightforward. I love this trailing-edge construction! The whole construction is fairly solid, but surprisingly (at least for me) heavy: 69g. That's as much as my whole Tiger Moth!

Above you can see the left aileron: The parts R9 to R11 are about 4mm short. No big deal, sanding will sort it out I guess, but they are rather shorter than on the plan and on the picture in the building instructions.

Yesterday I was in another town and had a look into the LMS: Cheap Graupner stuff and the right color for a Fokker factory finish, but I found it too glossy. No one seems to sell Litespan in Germany, so I guess I'll settle for Graupner Ecolite, seems to be about the same stuff. I haven't yet decided on the color scheme, however (suggestions are very welcome) - I'm considering Jacob's black bird.
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Old Apr 16, 2005, 05:44 PM
edi
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I've gathered the pieces for the upper wing next (ailerons done) and I'm pondering about the aileron servo boards now: According to their size, they have to be glued from below to both longerons and two ribs each, haven't they? However, they can hardly be meant to stick out below and spoil the airfoil, can they? Should they be removable to have the servos accessable? I guess I shall simply scallop the longerons and ribs to have them aligned nicely - tomorrow, it's rather late already and nobody seems to be reading this anyway ;-)
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Old Apr 16, 2005, 07:00 PM
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The servo boards are usually screwed to a pocket made in the bottom of the wing in the indicated area. The pocket is made from two ribs and 1/4" sq. balsa cross pieces. Most folks have their own favorite way of doing this so I left it ambiguous. The servos are then servicable by removing the servo hatches.

Kurt
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Old Apr 17, 2005, 06:11 PM
edi
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three wings

Thanks, so these are the covers. I know everybody does it differently but when I'm building a kit I like doing these things the way the kit wants them, that way I can only learn. Well, today I've finished the rough work on the wings and started the elevator. The leading edge on the lower wing is missing, I plan adding it after adding the 0.8mm balsa. I have to get some tomorrow.

I couldn't resist putting the wings on the struts -- worked wonderfully, no alignment problems! Taking into account that I'm a rather sloppy builder, this is really great. I hope I'll have as much fun flying her as I have building her!
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Old Apr 21, 2005, 05:41 PM
edi
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tail feathers

I got nice weather for my birthday today, so I spent some of it flying. The other days I have been working hard, so there were no build pictures

Building the tailplane went easily, too, can't figure out why there are two identical parts A2 in the kit, however.
I managed to get myself into some minor trouble with the fuse. I used white glue for gluing the ply reinforcement onto the sides and the warped nicely. I softened them with hot air and glued a piece of spruce vertically to them as can be seen on the first picture.
The motor mounting plate seems to be too long, however. Maybe you could verify that, Kurt? According to its length it goes through F1; but there are no slots where it could go through and I can't figure out what I could have possibly done wrong. There are pieces F3A and F3a, as it seems, which I found confusing at first.

Well, the weekend isn't far off, I hope the motor and the litespan will arrive soon ...
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Old Apr 21, 2005, 06:07 PM
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edi,
Well, you found some items that no one else has found. The motor mount is indeed too long by 1/8" so your fix is just fine. Yes, there are two different parts labeled the same. Both errors are now corrected in my parts file and plans. Thank you for pointing out the errors to me. The A2/A2a situation is for those builders who want to save tail weight and skip the addition of the center A2 balsa. That way the a2a's can do the job all alone but the model has a soft spot in the Stab. I prefer the fully wooden structure
as you have built.
Kurt
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Old Apr 22, 2005, 01:28 AM
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edi,
Although your build appears to be going well, it's still not too late if you really wanted removable wings. Had you considered doing it the way Flair do on their Baronette? The mid wing and fuselage top are built as one, bolt on piece complete with c/s struts. The top wing and i/p struts are permanently attached to the mid wing/decking/s/c struts. The bottom wing bolts on as a separate unit and has brackets for attaching the i/p struts.
So, not too much weight gain with this system because it uses very few parts that wouldn't be there anyway. However, the one piece structure of the standard kit works well - it's how I usually design my models and is well proven.

BTW, Bass is actually the US term for lime wood - wood from the lime tree - I'm told. It's a much better option than spruce, if you can search it out. Lighter than spruce but much stronger than balsa.

Kurt,
Sorry for sticking my oar in there mate, just seemed like a useful possibility for anyone wanting removable wings.

Pete
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Old Apr 22, 2005, 05:40 PM
edi
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Peter,

thanks for chiming in. It's so nice for me to hear an additional voice in my thread. I still have to decide on the removable wings. The point is that the Dr. 1 will probably fit into my Prius with the wings in place, but it would be hard for me to take anything else with me (second plane, family). Furthermore, we have a very old house with small doorways and getting it into the car from my hobby room on the 2nd floor might not be trivial - I managed to break the rudder of my much smaller Simprop Dr.1 that way. When I have the fuselage build, I will put everything in place and decide. (Today I only did the cowling, glueing and rough sanding.)


I thought to put the bottom wing and the middle wing in place by simply not gluing them, but holding them in place with a rubber band. I'm not sure about the top wing because of the cabane; however, but I haven't quite figured out yet how the cabane is supposed to work anyway. I wanted to have a stiff cabane fixed to the fuse and thought about holding the top wing in place with the rigging. The wing struts would simply be put in place and a piece of rubber band could be led through a tube in the middle wing and pull top wing and bottom wing together.

But Peter, I haven't quite understood the Baronette way of things. So the middle wing would be permanently attached and the top wing would have the cabane? But wouldn't that defeat the purpose of removable wings?

Currently I am a bit worried about two things:
1. The tail-skid is only glued to a piece of balsa. My old Lenger Fokker E.III broke the skid on its first landing, my Simprop Dr.1 has its second skid already and my always smoothly landed Sopwith Tripe had its skid reglued already. This bird will be much heavier and so I'm considering a shock-absorbing construction with a rubber band.
2. The elevator has a higher angle of incidence than the wings. I know this is possible, of course, but this is my first plane with such a feature. Anything I have to be aware of?

Finally, I have to add some kudos for you, Kurt: Only today I understood how excellent and professional (in addition to "fast") your shipping and handling was since I got my kits after a mere week w.o. hassle and I could pay my customs to the postman. Why am I mentioning this? My wife ordered s.th. from Japan and we had to go to the customs office (30 miles one direction) and take the package from there because there was some information missing

Cheers

Edi
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Old Apr 22, 2005, 06:00 PM
Designing on the edge
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United States, OR, Portland
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Edi,
Thank you for your comments. We try to get it right and are very happy when things go smoothly.
On your concerns, the Dr1 has a real sensitivity to tail heaviness so an elaborate skid might not be wise. If the tail is light, it will be less stress on the skid in landings.

The horizontal stab incdence is exactly as per the orginal airplane as are the incidences of the three wings. Most of my WWI models ( and all Fokker's )have the feature. It helps get the tail in proper alignment in flight.

Kurt
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Old Apr 22, 2005, 06:19 PM
edi
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Well, that's the main purpose why I have not yet decided to make the wings removable: I think that this might introduce unwanted deviations of the angles of incidence, however slight. And I want a well-behaved Dr.1. So when I build everything according to the plans as exactly as possible I will have better chances of getting one. I can always build another one with the plans and start experimenting from there.

BTW, have you considered other triplanes (apart from the Pfalz)? I find the NIeuport ones beautiful, but you could actually sign me up for any plane with more than two wings

Cheers

Edi
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