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Fokker Dr1 scratch build


mightypeesh
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Hi folks. a short while ago i got my mitts on an old Ace RC Ultimate - 33inch wingspan and powered (eventually) by an equally old MDS .17. She is such a blast to fly and it was on one of these many flights since that I decided that small really is beautiful and what I wanted is a small Dr1 that I could chuck in the car fully rigged, ready to go at all times! What the ultimate is missing however is any scale detail to speak of, which I intend to address here. It will definately be a sport scale build, at around 32" 1/9th scale but with little extras to make it more interesting.

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There is tons of reference material online, but am using these drawings as my primary source

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I also like to have a plastic kit when building as reference. I find it is easier to see what detail to put in and what to leave out with a three dimentional object. This one is a 1/48 scale one from Revell. I just chuck em together and point a can of grey primer at them to bring out detail - and all the glue drips I squirt around laugh

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Although I am designing this from scratch nothing will be ground breaking considering the amount of previous models in existance, although this is my first own design with a proper built up structure - so why not do one with 3 wings!

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I enjoy old school pencil and paper drawing and then when I need to refine a detail I will draw the part up on the computer as in the rib parts. Power is coming from an old OS Max .20 - another first design wise for me because my other builds have been electric.

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Pippin the workshop cat is keeping an eye on quality control as usual.

Design wise I am giving myself a bit of a chance by extending the nose a tiny bit to help with the CofG as well as enlarging the rudder by about 30%. I know these are dreadful at ground handling and ground-loop and nose over at the drop of a hat. I hope to improve this by moving the under carriage forwards with the nose, fixing the wheels to the axle so they both turn at the same time - apparently it helps tracking and (now don't tell any one this) I am going to make the tail skid steerable devil. How scale.

I am starting with the wings and have made up a kit of parts ready to go

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Lots of lovely ribs and strip ready to go. My mass rib making factory is here

**LINK**

More later,

Cheers, Simon

Edited By mightypeesh on 25/10/2015 11:06:14

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Ok folks best start with the top wing as I have lots of lovely ribs!

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Standard wing build. Spars with D box at front.

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I cut some aluminium sheet to make fittings for the wing struts.

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and used the wing rib jig to align it together.

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I decided to cap the ribs. To get them to curve I roll over them on a softish surface..

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which makes them easier to fit to the rib.

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I have extended the back of the 'D Box' as I wanted to give the impression of the ply fitted on the full size one - very sport scale though!

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Looking mighty good!

Cheers, Simon

Edited By mightypeesh on 26/10/2015 19:33:31

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Hi chaps. Pretty much there with the top and most complicated wing.

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I have made the servo hatches - I can just about squeeze in a couple of hs55's in there, and laid some wire along to where the cabane struts meet the wing. There are light ply plates under the balsa blanks on the left ready for fixings. I intend to run the servo wires down the inside of one of the struts, and will solder the extra on when it comes to it.

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ailerons made, just waiting for some hinges to turn up

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The other two wings are simple in comparison! I do love a naked built-up wing smiley

Cheers, Simon

Edited By mightypeesh on 27/10/2015 17:00:06

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Thanks chaps. Bit more done - I thought I would sort the horizontal stab out today to alternate with the wings.

Just out of interest I was rummiging in the bin bag drawer today and came across these.

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Not sure where they are from - probably Waitrose or Sainsburys, but as they are clear I thought I would try it as plan covering film. Bingo! The bags are 80cm x 75cm so double that when split and opened out and I have tried very hard with super glue and kicker and aliphatic as well today - and it all comes off clean as a whistle!

Anyway back in balsa land....

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Build flat

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And shape after.

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Same as the elevators - just sorting the joiner. When the edges are sanded round I run a bead of superglue around and let it soak in a sec before wiping it off to harden it and make it a bit more ding-proof.

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Eerrrm........ Thats it really......smiley

Cheers, Simon

Edited By mightypeesh on 28/10/2015 20:09:44

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I am pretty sure that when Mr Fokker was drawing up his plans for the Dr1 he had a roll of tape on his desk....

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...... so to keep things authentic I thought I would use mine too. Perfect size for the cut-out on the middle wing.

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I used the tape to make formers for the curve which I then bent some 1/8 balsa around before sheeting the top

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I then switched to my other roll of tape which is a bit smaller in diameter and double-sided a bit of abrasive paper to it (I do like a bit of tape and sand paper!) to keep it all nice and square.

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The roll of tape swings into action again!

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Onto the bottom wing. I am using all the same ribs, just adjusting them as I go.

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No mistaking which aircraft this is going to be. I did a quick count-up of the number of separate parts that make up these wings and got to around 360-ish. So much for my quick and easy build idea!

Onto the fuse next.

Cheers, Simon

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Hi folks. Got onto the cowl next.

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Drew up some plans and cut a bit of blue foam to use as a buck.

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and put a bit of parcel tape around the edge

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Tacked a strip of 2.5mm balsa around with cyano, then laminated two layers of 0.5mm ply around with pva glue.

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Add a couple of layers of 6mm balsa and glue to edge of laminations only - not the blue foam.

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1mm ply in the middle and a ring of 1mm balsa around the perimeter - if you just use ply to the edge it would create a ridge when shaping.

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Finally a ring of 1mm balsa glued to the front.

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marked up to cut

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and sand to shape. Another bit of abrasive stuck on with double sided! This time I cut a bit of blue foam to the desired radius for the cowl.

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Time to cut out the buck.

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Bit of sanding then it will be ready to be glassed.

Cheers, Simon

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  • 1 month later...

Hi folks, been a bit under the weather so not been in the workshop for what I have noticed by my last post is nearly two months ago! I need to get a shake on as the queue for the building board is getting restless and I am really looking forward to my Ballerina/Fly Baby build but will finish this one first.

I thought I would break myself back in with making a nice pair of vintage type wheels for her based on these which have a laced up semicircle cut out for the valve rather than the round hole that you see a lot.

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I had been thinking for a while about using the 'shrunken plastic bottle canopy' type technique to get the effect of the spokes peeking through the covering, so this is a bit of a test bed to see if it works as I expect. So here we go with my vintage style wheels.

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A bit of drawing to work out where it all goes. as the spokes only touch the cover near the hub I just need the wires to be at the correct angle and terminate where they hit the plywood away from the surface.

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I wanted some wire that is soft enough to bend with plyers so used normal galvanised steel wire off of a roll rather than hard piano stuff. Obviously it is all wonky at first so we need to straighten it up. Cut off a bit and put one end in a vice and the other in your drill....

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pull it out tightish and spin the drill slowly.....

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Shortly it will twist and go nice and straight (with a slight spiral effect on the surface). The more you spin it the more brittle it becomes when you bend it, so experiment as you go. Oh and wear some eye protection in case it snaps and pings back! You should end up with a nice bit of straight wire to play with.

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This is definately an experiment and a stand off scale wheel, so I hand drew and drilled the holes, but it is doing the job.

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Looking good. Once complete wick a bit of glue down the holes to stop it all falling apart.

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Pack it up well in a plastic bottle and shrink the bottle around it with your hot air gun. It takes a bit of practice at first as you need to 'chase' the shrinking around to get it to pull down where you want it to, Its a bit hard to take a photo of a slightly raised bit on a clear piece of plastic, so it will have to wait for the primer before you can see it!

I am going to use these as hubcaps over flat wheels to cover the collets so will make these next.

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On a forage around the workshop I found a piece of 1.5mm HIPS which would do for the outside faces of the wheels themselves. I am going to layer it with some soft balsa in the core to seperate them. I have a small band saw so cutting nice circles is a doddle.

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Layer the sheets together with a bit of double sided and draw you circle on. I use a piller drill to drill the center hole - you can do it freehand if you have a steady hand, but it has to be a vertical hole! drill another hole in a bit of ply as a base and then push the drill bit into the base with the material to cut on top so that it rotates accurately on its axis. Cut into the board and material to the edge of your circle so that the axis is aligned with the blade and clamp in place on the cutting bed. Now just turn the material like a steering wheel......

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Tadah! Takes longer to explain than do. In the back ground is one of the caps primered up - the spokes have done their job! I am going to put a brass sleeve through the centre of the wheel for the axle to slide into with a collet attached. I found this nice little pipe cutter in Ikea for a couple of pounds (kitchen department I think) It is great for smaller stuff like this.

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As I am going to have the wheels fixed to a rotating axle to help fight the 'ground looping' on Dr1's the collet need to be attached to the wheels to stop them spinning independantly.

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To this end I am soldering the sleeve to the collet and adding another bit the other side to glue a bit of ali tube to as a pretend hub. It will also be epoxied in place on the wheel. I mounted a bit of dowling in the drill and turned it down to a tight fit to keep the bits aligned whilst soldering.

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Not the neatest job in the world, but shoud do the job.

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Then epoxy into the wheel assembly.

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The little post is to epoxy the bit of aliminium too - otherwise I know that on the first landing they will pop off again!

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Right, last bit. On to the covers. i added paper circles to the centre to give the impression of re-enforcement around the hub, and the semi-circles to the edge. I used paper on double sided to hold them in place and then soaked it in cyano to fix and harden it. Although the real one has lugs that the cord is laced around to hold the flap shut I am just drilling the holes and going to thread it in and out.

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The thread and wire around the house was either too thin or too thick for what I needed so I made my own up. I used a bit of stripped out lamp flex and seperated five strands of wire which I spun up again using the drill.

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I wicked a bit of solder in one end to act as a needle to feed it through the holes. If I were using thread I would wick super glue in to harden it up.

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A bit of superglue wicked into it to keep it all in place.

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I am using 10mm Neoprene cord for the tyres, cut to size and the ends superglued together. Steady hand required!

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There we go - ready for paint. I am quite pleased with the outcome and think the spokes look particullaly good. The neoprene joint has a line around it that I need to clean up, and I would look for some thread rather than wire for the lacing next time and the paper looks a bit clunky. Mind you - to me at least - they look better than ones off the shelf (if you could even buy them in this scale!) and much more satisfying to make.

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Better get on with the fusalage to hold all these bits together!

Cheers, Simon

Oh, forgot to mention - The hubs will be fixed to the wheels after they are on the axle, probably with a bit of silicone to make them removable. Just in case!

 

Edited By mightypeesh on 06/01/2016 10:18:44

Edited By mightypeesh on 06/01/2016 10:22:59

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  • 4 weeks later...

Thanks for the comments folks!

Ok. been going a bit slow on this one but got around to starting the fuselage.

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Out came the pencils and rulers again

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Nothing unusual - 5mm square longerons with a box at the front for all the gubbins.

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I extended the box at the front to the cockpit sides to give me a solid bit to hold when starting. I will add some formers to brace the sides when I work out how it all fits in - I am doing the 'suck it and see' style of design!

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Tis getting there slowly......

Cheers, Simon

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