Topic: Dornier Do D1 build thread

Posted on behalf of Dave Jones

Well, I've started the Dornier and  the attached photographs show the progress to date. It's a long time since I've built from a plan and so I've been doing a fair amount of head scratching. I must admit I do prefer bona fide kits where you get an idiot's guide that tells you  to stick A to B and then tick the box.
 
I've started with the lower wing as it appears to be a fairly straightforward build. It's gone together without too many snags, apart from a couple of riblets at the tip that I've had to manufacture because the supplied riblets were of the wrong profile. The lower wing is to be a one piece affair which does aid construction (providing you have a big enough work bench). It consists of three 1/4 x 1/2 inch spars, top and bottom, and they are webbed on both sides throughout their entire length. AZM recommend 1/16" webbing as per the plan, that's fine for a 60" Sunday flyer, I've opted for 3/32" plus, I've included 1/4" soft balsa infill in both the leading and trailing edge spars as far out as rib 5. This is a biplane but remember, there are no interplane struts or rigging, so each wing has to "fend for itself" so they need to be rigid. I am lead to believe that the wings on the full size prototype weren't up to the job, I want this model to fly in a scale like manner, not crash in one!!
 
The first picture shows the plan on the bench, I wouldn't normally cut the plan into pieces as I like to save them for future reference but, in all honesty these aren't worth keeping and, they are more manageable in smaller pieces. Don't worry, they will still be usable when I've finished with them. The rest of the pictures show the basic skeleton, followed by the rib webbing then the leading edge riblets. I'm quite satisfied that the construction is straight and true, as can be seen where the wing is shown standing unsupported on its leading edge.  For any anglers out there, look at the photo of all those gaping fish!!


Dave Jones

OOO goody, a new build thread 

Is this a 1/3 scale steed for the DP 

Mud

mmmmm I hope so.....

Pretty little thing don't ya know?

Yes, this is the 1/3rd steed of Von Tap and will be part of DP

Steve

Interesting subject, very unusual 

Good job davey. if you can get me the  profiles for the modifieds tips I can make sure they get changed on the plans for the next guy

Will try and do prof. The replacement riblets are near, but not dead on yet, to an ideal profile. I'll sort that out when I come to the leading edge sheeting, a bit of trial and error will be required and then I'll draw round them.
Regards,
Jonesey.

I left off some time ago where I had completed the basic frame work of the bottom wing and had finished all the spar webbing. I then set about completing the centre section cutaways at the leading and trailing edges. The front and rear faces were made up of 1/4" balsa sandwiched between 1/8" light ply which were then epoxied to the the ribs, the joints then reinforced with 1" triangle. For mounting the wing the plan shows a single dowel in the centre of the front face with a balsa block support, and two triangular gussets for the wing bolts at the rear. I will fit two dowels which will extend rearwards through the leading edge spar (which has a balsa infil) and two ply plates across the rear to sit flush with the top of the ribs for the wing bolts. This will be done when the wing is ready to be fitted to the fuz. The cutaway sides were then made up from hard balsa and sanded to shape.
 
Next up came the wing tips, which I have made up by cutting a 1/16" ply core and laminating it with 3/16" balsa on both sides. These will eventually be sanded to a rounded profile. The tips were then fitted to the wing and, in order for the spars to taper to the tips, I "cracked" them at the outer two ribs, filled the saw cuts with epoxy and then installed the last of the webbing. I know spar webbing doesn't usually extend as far as the tips but, having now seen some of these large biplanes in breezy conditions, I've noticed they can be prone to dragging a tip along the ground, even when only taxiing, so I thought a little added strength wouldn't go amiss. The leading edge, which is a strip of 1/2" square balsa, was then glued into the "fishes mouths". After a light sanding to check all the ribs and spars were level I was ready to start the top sheeting.
 
I was conscious that I needed to keep the wing flat and the leading edge straight to prevent any twist being built in, so I weighted the wing down with several 1 gallon fuel containers and a length of aluminum square tube clamped to the leading edge. Once satisfied that all was true, I began to sheet from the rear spar forwards, using 3/32" x 6" x 48" sheet. I thought I would be able to sheet each wing panel in one piece from the centre section outwards, chamfering the underside of the sheet where it met the tip. Using plenty of pins and clamps I did this, using Aliphatic glue to give me time for adjustments and a strong bond. Both panels were sheeted from the trailing to leading edge spars and also the centre section. The whole thing was then left overnight to set.
 
When I removed the pins and clamps I was very disappointed with the sheeting at the outer two rib bays. Because of the complex curves at the tips the sheet had distorted and looked a mess. I decided that I would remove the sheeting from these outer bays and sheet them separately. The sheeting from the tip to the last rib was fitted cross grain in order to follow the curve without any stress or distortion.
 
I then set about the leading edge sheeting. The plan shows the sheeting butting up to the leading edge, which is then sanded to a rounded profile. I've never liked this method as I've found the sheeting can be prone to sagging between the ribs if a perfect joint isn't made. I decided to sand the leading edge flush and sheet over it, resulting in a much stronger joint. Again this was pinned and clamped and left overnight to set. The underside leading edge sheeting was then fitted in a similar manner.
 
When all was set and dry, the leading and trailing edges were sanded to shape, along with the tips. The wing was then given a light sanding, with a touch of filler here and there where the sheeting was joined. I'm quite confident that then structure is true and should be more than strong enough, and that I have only deviated from the plan on one or two minor points.
 
It has taken me 90 hours to get to this stage. My next decision will be to start the top wing or get stuck into the fuzz. I'm afraid some household chores will have to come first to keep the wife happy then, if the weather doesn't improve, it will be back to the workshop.

I left off where I finished the lower wing and so I thought it was time to turn my attention to the fuselage. I started by identifying and sorting out the formers etc, not as straight forward a job as it should have been, none of the parts in this kit have there part numbers on them, some are missing altogether and some of the laser cutting was "incomplete" especially on the thicker components. Once that was done I just happened by chance to offer up one of the wing seat laminates to the bottom wing....it was a mile out, the cut out being 1/2" too short and completely the wrong profile. This lead to a lot of checking, re checking and cross referencing. The supplied part matched the outline shown on the fuselage side elevation of the plan, which is deferent to the corresponding rib section on the wing plan and rib outlines. The only thing I could do was re cut the wing seats. To alter the supplied laser cut wing seats would leave me with very little material left so I decide to start from scratch by making two new wing seats. Instead of laminating 4 x 1/8" light ply pieces for each side, I decided on a lamination of 1/8" light ply and 1/8" birch ply. I believe this will be more than sufficient as I intend to skin the entire fuselage in ply, not balsa.
 
Having satisfied myself that the new wing seats were correct and that I had not altered the angle of incidence, I began to lay out the basic fuz side framework from 1/4" square strip so as to match up with the other 1/4" light ply components. The bottom of the fuz, B6, curves up from the wing seat to the nose, former B1. Both these parts were missing, I traced out the curved B6 from the plan, but I had to "create" B1 as I have been unable to find any outline for it anywhere.
 
The basic fuz frame is slab sided so, before I went any further, I skinned them both with ply whilst flat on the board. 1/16" from the nose to aft of the cockpit and then 1/32" to the tail. A 1/4" light ply former is supplied with the kit and, according to the plan, it is a mounting plate for an electric motor, but it also determines the curve at the front end. I glued this in place, along with formers B1 to B5, which receives the wing dowels. The supplied B5 has very neat lightening holes cut into it, unfortunately in the same place where the holes for the wing dowels will go, also there are two rows of 1/16" holes where the rear undercarriage wire should be "stitched" to it.....not on a model this big. I replaced B5 with a solid piece, the undercarriage will eventually be mounted in transverse grooved hardwood blocks. Most of the light ply motor mount will eventually be removed, leaving the outer edges to maintain the curvature at the front of the fuz.
 
I then determined the location of the firewall. The firewall supplied with the kit consists of two pre cut sheets of 1/4" light ply, which would be laminated together. Once I had determined the location for the firewall, I found that the pieces supplied were too small, so I made up a new one out of birch ply, 3/8" thick. The firewall was then reinforced with 1" balsa triangle back and front and the framework in the engine bay area was infilled with 1/4" balsa. The remaining 1/4" light ply bottom formers from aft of the wing seat to the tail were then added.
 
I then turned my attention to the top decking. The formers are made from1/8" light ply so I have added a collar of 1/8" balsa to those where I anticipate a joint in the ply sheeting i.e, where there is likely to be a compound curve. Apart from the top 3/8" longeron, there are no pre cut slots for the stringers in the aft turtle decking formers, so I attached them temporarily and, using a length of string, marked out where they should go. The slots were then cut and the formers glued to the top of the fuz and the 1/4" balsa stringers added. I have also added 3/16" square strip between the top and bottom formers to act as a joining seat for the remainder of the fuz sheeting.
 
So, that's as far as I've got to date. I'm satisfied that the fuz is straight with no twist, and that the lower wing sits accurately. The next task will be the forward top formers and cabane struts.....more head scratching by the look of it.

Good work and well done overcoming the problems.  Sounds like you may as well have bought a plan and worked from there as you appear to be re cutting so many replacement pieces!

Its's not so much replacement pieces as missing pieces. Anyway, I've had a change of plan, I've fitted the lower wing today and I've decided to concentrate on the bottom of the model while it can still sit comfortably on the bench upside down. I'll do another update with pictures as and when.   

I left off where I had marked out for the stringers on the aft turtle decking. The slots were cut and then the formers glued in. The main 3/8" square longeron along the top and four 1/4" square stringers were then added. Now that the rear of the fuz was rigid, I commenced to mount the lower wing. 1/4" birch ply plates were inserted in the wing to sit flush with the top of the ribs and a 3/8" ply plate epoxied in the fuz. Once satisfied that all was square and even, holes were drilled for the 3/8" dowels and the 6mm captive nuts. The wing fits snugly up to the fuz with no gaps.
 
I then decided that I would sheet the bottom of the fuz and it was then that I realized I'd failed to cater for the bottom stringers, again, the formers had not been pre notched. I had to cut out the notches for the stringers while the formers were in situ, having already been glued in. Again, I decided on a 3/8" square longeron along the centre and two 1/4" square stringers. I then sheeted the aft section with 1/32" ply. I then realized I had failed to notice on the plan that there are in fact four stringers along the bottom but, considering that I am sheeting in ply instead of balsa, I am confident that the structure is more than strong enough. The plan shows a hatch immediately behind the wing to allow access for mounting servos. This is no doubt required on the 1/6th scale model where space would be at premium, but I believe it is not required on a model this size plus, in my opinion, it would be detrimental to the structural integrity of the model.
 
The forward section was then next up for sheeting. There are no stringers shown on the plan, but I need something to sheet to, so I decided to do the same as the rear section. Unfortunately the question of lightening holes popped up again, with holes in the centre of the formers exactly where I need to notch out for the 3/8" square. I decided to cut through and added a 3/8" wide by 5/8" deep balsa "crutch" along the centre to maintain the structural integrity of the formers. Due to the compound curve of the underside of the nose section, I sheeted it, again with 1/32" ply, bay by bay, leaving the aft bay open, pending the addition of the undercarriage bearers.
 
Now that the front of the fuz was fully sheeted it was time to cut the electric motor mount M1. I had left this job until as late as I could as I was concerned that the unsupported front of the fuz might splay out. I made several reference marks and took measurements to check for any movement. I cut through M1 and found there was no movement at all. I then removed the centre of M1, leaving a substantial amount of material along the sides to maintain and support the curvature of the fuz at the nose. What is left is somewhat unsightly due to the lightening holes, but I will tidy that up when I come to the construction of the removable nose section.
 
I then trial fitted the upper forward formers and added the cabane struts. Again, AZM have been over zealous with lightening holes. The formers are already made from "liteply" so the weight saving is minimal compared to the amount of loss of structural strength. The whole assembly feels flimsy to me. I know once it is all glued together it will be a lot more rigid, but I don't think it is up to the job. Also, the top of the fuz forward of the cockpit windscreen is flat, yet some of the formers have been cut away as can be seen in the photographs to cater for the scale mounts for the machine guns. Again, if I leave the formers as they are I will have nothing to sheet to.
 
I think the best way forward is to add a full lamination of 1/16" birch ply to each former to give added strength and rigidity, make all the formers full profile so that I can add stringers to take the sheeting, and the forward most sub formers, C1, to be scrapped and a full width former added in their place. I would welcome any thoughts and/or suggestions re my modifications before I go ahead.
 
To cheer myself up, I bolted the lower wing to the fuz while the top formers were in situ to see what progress I was making. I must say it is starting to take shape and looks quite a brute of a thing. While I am pondering over the mods to the top formers I will make a start on the framework for the removable nose section and probably turn my attention to the tail assembly.

Steve
She looks very good, reading the text you seem to have an awfull lot of issues to resolve during the build but it looks like you have it well under control, I imagine we will be seeing her at Cosford ??  will the tail section be removable as per the Albatross ??

Steve
She looks very good, reading the text you seem to have an awfull lot of issues to resolve during the build but it looks like you have it well under control, I imagine we will be seeing her at Cosford ??  will the tail section be removable as per the Albatross ??

She does indded look good 
Kit 1 of 12 AZM and lots of issues already  Can't wait to get mine   

 CB, Steve is posting this on behalf of Dave Jones 

Steve
 I imagine we will be seeing her at Cosford ??  will the tail section be removable as per the Albatross ??

Dave, as young Mud says this is being posted on behalf of Dave, and as for my Alb tail, all i will say is you had best keep an eye on your Tripe when it comes out to play

Steve

looke great pls do me a favor and take notes on any changes that were needed etc so that I can tweak the plans. thats one of the things I am wanting to do to try and help jaime out and thats fix problems ppl find with the plans for some of these unusual planes that havent been built much.

looks great though

Dave, as young Mud says this is being posted on behalf of Dave, and as for my Alb tail, all i will say is you had best keep an eye on your Tripe when it comes out to play

Steve

I am deeply shocked , hurt,dazed and confused by this openly aggressive reply, ( I could write a good rock song on that theme) As we should be taking to the sky at the same time, ( Me with my superior English airoplane ) I strongly suggest you fit a smoke machine , and we will duel in the sky, obviously as my flying skills might not be fully sharpened to perfection, you might need to give me a bit of room... Seriously though will she be a flier by Cosford ?? it would be great to see, also does anyone know how the sheep is getting on with the LGV  ,

Hello Prof,

I am keeping a note of mods and mistakes. I'll hang on for now and give you a full list when I have finished my involvement with the project, ie the basic airframe, which I'm hoping to have completed by Christmas / New Year.

Re my request for input re the upper front formers / cabane supports, after a good chat with Ken I've laminated them both sides with 1/16" ply and notched them for stringers. The assembly is as strong as anything now so...problem solved.

also does anyone know how the sheep is getting on with the LGV  ,

  Lol

also does anyone know how the sheep is getting on with the LGV  ,

 i think he was "fleeced" 

  chris

If you are able to read this, then Steve's "tutorial" has worked and I have finally managed to work out how to attach pictures to the build thread.

I left off in a quandary re the top forward formers. After discussing the matter with Ken, I decided to laminate the formers on both sides with 1/16" ply as the original formers are too fragile. A trial fit was done and the location for the stringers was marked and the notches cut.

Once this was done I fitted 3/16" square gussets to help locate them correctly and to provide a larger gluing area. The formers were glued in place and the stringers added. This must now be the strongest part of the model, it certainly looks it.     

Nice one Dave 

Steve

I then decided to sheet the cockpit area. The plans show a former that sits in the middle of the cockpit opening to assist with keeping the shape of the sheeting. The majority of this is then cut away as the opening is cut, leaving a stubby former either side. AZM only provided the two stubbies, so I made up the full former out of 1/8th ply and laminated the two stubbies to give me a 1/4" sub former. The 1/32" ply cockpit sheeting was then added and the central joint reinforced with pieces of ply. The cut out for the opening was then drawn on the sheeting, but I will leave the actual cutting out for another time as the sheeting has added more rigidity to this part of the fuz.    

Thanks Steve, aren't things easy when you know how it's done!

While the fuz is still at a stage where it is easily manageable on the work bench, I decided to turn my attention to the tail feathers. I've commenced this with the tailplane and elevator. The tailplane is basicaly a flat bottom section with with a slight airfoil shape on the top.

The leading edge is 1/2" square with the trailing edge being 1/2" x 3/4". I decided to deviate from the plan by laminating the tips from a 1/16" ply core as per the wing tips, and then adding 3/16" balsa. Slots were cut into the leading and trailing edges to accept the ply core before they were pinned to the board. The central spar is but joined to the tips on the plan, I wasn't happy with this so I decided to notch the tips to accomadate the spar, making for a stronger joint. The tips were then glued in position and the spar added.

The 3/16" x 1/2" ribs were then added. Because the scale outline is smaller than the full tailplane on the plan, the scale tailplane is a rib short. Refering to photographs of the full size aircraft, I took the liberty of adding an extra rib inboard to keep as true to scale as possible. The airfoil shaped riblets were then cut out and added to the top side.

Cheers Al, I'm really getting the hang of this Forum malarky.

I then made up the elevator in a similar manner to the tailplane, but I've made the trailing edge the same as the wing, from 1/8" balsa sheet. There is no airfoil shape as such, it just tapers from the 1/2" x 3/4" leading edge to a point at the trailing edge. The whole assembly was then sanded to shape.

I've used large "Kavan" flat hinges to hinge the elevator. Once these were fitted the tips were aligned and shaped to match. The leading edge of the elevator was then sanded to a rounded shape.

I then manufactured the control horns from 1/16" glass fibre sheet and added them as per the plan. A 3/8" wide balsa surround was then added at the base of the horns to take the covering as and when.

My final job for the day was to fit the bottom wing and trial fit the tailplane to see how it looks. I'm quite happy with the results and it looks as though it is nicely in line and level with the wing when viewed from the back.

Thats it for now, next up will be the fin and rudder.

The fin is a fully sheeted unit whith the rudder having an open framework. I made the rudder first. It consists of a basic 3/8" square core with a laminated tip (1/16" ply and 3/16" balsa), 3/16" balsa riblets to give it an airfoil shape and 3/8" square strip for the leading edge. The whole thing was then sanded to shape.

Dave, I assume the plan rudder was over scale as yours seems quite a bit smaller?

Steve

The fin was then constructed in a similar manner, with the leading edge being made from 3/8" sheet balsa. The hinges were dry fitted and the framework was then sheeted with 1/32" ply. I was hoping to be able to round the leading edge off by flairing the ply in to nothing. I wasn't happy with the results so I sanded it back to a flat and added a 1/8" balsa strip and rounded that off. The control horn was made up from 1/16" glass fibre sheet.

All that was left then was to trial fit all the tail feathers to the fuz. I've notched the bottom of the fin post so that it sits over the 3/8" square central longeron at the bottom of the fuz, this gives it a more secure fixing and also helps with alignment. I think the final result is quite good and the tail end is starting to look like an aeroplane at last.

The next job will be the removable nose section, a task I have been putting off too long.

Steve,

yes, all the flying surfaces are over size, with a scale size dotted outline drawn on the plans. The oversize outlines were for the electric version. It was agreed at the outset that all outlines would be to scale.

Jonesey

The time has come to make inroads into the construction of the removable nose section / cowl.  I've been putting it off for sometime because, after checking the laser cut parts, I knew i wouldn't be using the majority of them and that I'd be basically building it from scratch.

Here's a couple of pictures from the plan.

The next picture shows some of the pre cut parts for the construction. Due to their either being the wrong size or the wrong material, I will be using four of them.

I started by cutting out two base plates N8 and sanding them to shape to match the curviture of the fuz. The two supplied would have sufficed but they were cut away at the back and I had decided I wanted to keep them square. I then sat them in situ and temporarily joined them with a couple of cross pieces to act as a jig. I then marked off the position of the upright formers N9 to N12. All these pre cut parts were too short and the radius at the top did not match up with the fuz, so they had to be re made. I added balsa fillets to assist with locating the uprights and glued them in position.

I then added the horizontal former N7, which would form the base of the top half of the cowl. This was supplied in 1/8" lite ply but it should be 1/4", so I cut another one out of 1/8" and sandwiched them together. The four curved stringers / horizontal formers N14 were then added.

To maintain alignment of the upright formers while sheeting, I added temporary cross braces. The lower sides were then sheeted with 1/32" ply. The top half was then sheeted, because of the double curvature at the front, the foremost part above the top stringer is left open and then filled with balsa block, carved to shape. Once done, the entire piece was sanded to fit.     

Some more pictures

My thats ugly, very well built but ugly

What were the guys at Dornier on??

It looks quite solid, any ideas on weight up to now? I know its due for quite a lot of Litho skinning which will add a bit more. In your kit info Jonesey, does it mention covering? My main info shows hexagonal patterned fabric, not lozenge, but I have some other info that shows lozenge too

Ian.

Next up came the lower front of the cowl. This is shown on the plan as being carved from balsa. The parts supplied were cut out from 1/4" lite ply, presumably to be laminated together. I wasn't too keen on this approach and, as the parts supplied were too small the decision of how to go ahead was made for me. Also, the "cheeks" at the top were cut out instead of simply being etched, so I decided to leave them on. Any panel lines can be added during the covering and finishing phase. I cut a back plate of 1/8" ply and laminated that with balsa, one half at a time, and carved / sanded it to shape.

I think ugly might not be enough to describe this one, it certainly is different though and should make life easy for the "Fat Controller" when he's trying to identify different models. The plans I have show a lozenge pattern. As far as weight is concerned I'll get back to you, but a general consensus at the moment is that it feels quite light for its size.

The "cheeks" are faired back to nothing, which again was accomplished using balsa block.

Got any pics of IT assembled in all its godawfulugliness glory?

Ian.

All that was needed now to finish the cowl off was the radiator. Again, I wasn't able to use the parts supplied, this being due to mods of my own devising, so I had to build this from scratch, a straightforward but time consuming affair.

The grill is supposed to be brass, I couldn't find any brass mesh anywhere for love nor money, so I painted some silver mesh with gold enamel, along with the inside of the structure which is see through. I will not attach the radiator to the front of the cowl as there is some further scale detail to be added.  

So, after just over a full week in the garage, some 40 odd hours, the cowl is finished. The more work I do on this model, the more "brutish" it looks. The plan is to start on the top wing next week, once thats done I will be way on the road to completion as all that will be left is the U/C and the cabanes, which are not as straight forward as you might think.

Heres a couple of pictures of the progress to date.

You know when something keeps nagging at you and won't go away.......well, that's me and these cabanes. I decided some time ago that I would be replacing the ones supplied, (1/4" liteply, full of holes, that wouldn't support a strong breeze, never mind a 9 foot wing) with proper 1/4" Birch ply. The trouble was I still wasnt too happy with the amount of support within the fuz itself. So Alan Cantwell and Ian Redshaw went well out of their way and came round for a visit last Monday night, thanks guys!!

After two hours and a couple of brews in a cold and draughty garage, we came up with some mods. Basically, the idea was to tie the top of the fuz, in the area of the cabanes, with the bottom. This meant making two pairs of full length formers that would connect the leading cabane section to the front former that accepts the lower wing doewels, and the rear cabane section to the lower wing bolt plate. The new cabanes themselves would be deeper, extending upwards to fit flush with the top sheeting and lower, to slot into and key better with, the slotted top formers. The whole section will now be fully interlocking, you couldn't beef this area up any further if you poured on a gallon of Bovril mixed with a raft of Oxo cubes.

Extra reinforcing was added to the top longeron in the cockpit area, and a 1/4" ply plate was added connecting the top of the firewall to the underside of the top four formers, to prevent movement likely to be caused by engine vibration. Last, but not least, provision was made for a tank platform.

So far, I've glued in the longeron strengtheners, the front formers and the support plate for the firewall, the rest are dry fitted until I fit the cabanes.