dH2 from scratch

[Roy Hill 3]

After watching a terrific video about the construction of a scale World War 1 dH2, I had to have one. I found a set of free plans on the Internet, which I printed off and then enlarged to give me a 1.50 meter span model.

It was a bit of a task to work out the amount of timber required as this was my first attempt of building from scratch! I have built from kit before, but this is a whole new 'ball-game'. I soon became apparent to me that having blown up the plans, the thickness of the lines also increases! I made the decision to try to use the middle of the lines. So far it has worked.

Another thing which dawned on me was that.........if the length and width of a piece increases, does the thickness? Not necessarily. Some items will need 'beefing up a bit', but not everything will need to be increased. Much head-scratching ensued and off I went to get some of the timber and the aluminium tubes which form the majority of the fuselage..

I decided to to make the wings first, bending and laminating some thin strip wood to make the leading and trailing edges. That was an education! I had done some research on this forum and I found that making the ribs not too difficult.

The following picture shows the result of a good deal of balsa-bashing. Very rewarding. The lower wing is still in 2 pieces until I nail them to the fuselage!

I elected to go the electric route as starting an IC engine in 'pusher configuration' among lots of rigging and control wires would put my fingers in severe jeopardy! I, therefore used a power-train from a previous, rather unsuccessful project:- Tornado Thumper motor, Hacker ESC and 10s LiPos. New RX, servos etc were bought along with piano wire, hinges, Antique Solartex and other sundries.

I cleared the decks for an all-out assault on the relatively small fuselage. Constructing the 'servo, flight battery and Rx' platform allowing for LiPo changing access gave more than 1 opportunity for a 'Tea-break.' If one thing fitted, something else didn't.

Needing a break, I had a go at building the under-cart. It's a fairly simple construction and I was pleasantly surprised at my result! I know that the wheels in the picture are wrong, but they will suffice until the real ones arrive. I will return to the fuselage tomorrow.

The project, so far has taken me about 2 months and dozens of of tea-breaks. I don't expect to see it in the air until next Spring, but I will make another posting when there is some tangible evidence of my labours. Happy landings, Roy

[Dave Hopkin]

Going to watch this with interest, the WW1 Pushers have always been a favorite type of hairyplane of mine and its a De Havilland too what more could you ask for

[john stones 1 - Moderator]

That's a good start Roy, I like to see something a bit different

John

[Colin Leighfield]

I think that's brilliant Roy, a great subject and a great job you're making of it as well.

[Roy Hill 3]

Hello again, folks. Time for another gripping episode of this thrilling saga! After a bit of time flying, I recently got back to the dH2. I wanted to construct sides for the fuselage, and the only ply available was from an old MFO box. (Any readers who served in H.M. Forces will be aware of the adaptability of said boxes!)

I was not happy with the layout of the servo tray so a Mk. 2 was constructed. In order to keep the intended C of G in the right place, I needed to fit a prop extension. Guess what? Not available for that motor! I could have made my own but that would have been too time consuming. The only other option was to make stand-offs thus putting the prop in the right place, but this might need a small church roof adding to the cockpit front!

The fuselage inside was given a coat of paint to 'tart it up a bit' and the whole box was 'trial fitted' into the lower wing. The exit holes for the rudder and aileron lined up perfectly, so with a big grin it was time for a cuppa and a hob knob.

The above picture shows the new servo etc layout and the switch/charging port fitted. Because there might be a need to remove the elevator servo, I fabricated some fixing brackets.

I've used some fuel tube as a guide for the rudder and aileron wires. I have also extended the fuselage to accommodate the 10s LiPo.

ESC and all servos fitted. Rx and flight battery trial fitted and the elevator linkage constructed and installed. Once I am happy with all the innards, all the wiring will be concealed under the false floor which will be easily removable. Time for another tea break!

Everything in situ and looking pretty good. It was at this point that I decided to put it all on the scales and prepare myself for a shock. Wings, tail feathers, undercart and fuselage complete weigh in at about 7lb, which was what I estimated, so I'm happy.

I had made the cockpit roof some time ago by butt-jointing, soaking and wrapping 2 sheets of 2mm balsa round a a paint tin over night. It needs a bit of fettling. I just could not resist the temptation to put it on to the fuselage to see how it would look.

So far, so good. I have given up trying to source the correct wheels so I am making my own! I've got some Hoover drive rings which are the right size for the tyres and I will now cut out some Lite-ply wheels and take it from there! I predict some head-scratching and tea-drinking on the horizon. Happy landings.

[Martyn K]

This looks great. I really must start a WW1 Scale model soon.

Subscribed

Martyn

[Roy Hill 3]

Hello all. The Labour of Love continues with my dH2. For the last few days, I have been working on the undercart.. I found some strong but light ply, which was suitable for the wheels.

I used the outside size of the drive rings as a guide for the diameter of the wheel. This, hopefully, will allow the tyres to be under a bit of tension, thus keeping them on the rims during some of my questionable take-offs and landings!

To ensure that they were as round as possible, and as I don't have a lathe, I secured them in the chuck of the pillar drill and gave them alight sanding. With a round file, I then created a groove around the rim to further grip the tyre onto the rim! You'll need to look closely at the picture below for evidence of the groove!

Lurking in the corner of the workshop, I found some perspex which proved to be perfect for producing the conical shape of the wheel assembly. It was a bit of 'trial and error' getting the right diameter to create the correct cone.

A neat radius cut was made for the 'overlap' to produce the cone.

The perspex was offered up to the wheel and a score was made to form a good joint.

The segment was removed and the cone was created. It was held in shape with strong tape and then given a 'squirt' with a Hot Air Gun to ensure that it held. A good application of Uhu united the 2 pieces and all that was left was some decoration.

I'm not sure if the dH2 had 'quartered' wheels but as this was an experiment, it won't matter for the moment!

The next step is to attach the wheels, using Uhu again and soldering the undercart assembly together.

Bet you can't wait for the next episode, can you?

[john stones 1 - Moderator]

No I can't

John

[Kevin Wesley]

Hi Roy, Noticed your article. I've built two DH2's one electric, and one at third scale petrol power. I love em ! I made my own wheels, it looks very realistic if you glue balsa "spokes" round two discs of light ply with balsa sandwiched between , then you can cover it with solartex,.looks just like the real thing. I have pictures of my electric model on my photo album on this site, if you want insparation

Best regards Kev Wesley

[Dave Hopkin]

Oh a flying MFO box.... last time I saw one of them it was coming out of a barrack block window at Lippstadt, the glide path wasn't good, I suspected at the time the CoG was all wrong!!!!!

 

Subject Choice - 10/10

Difficulty - 10/10

Wow Factor - 10/10

 

Love it.... more updates please

Edited By Dave Hopkin on 20/09/2014 15:58:05

[Roy Hill 3]

Hello Folks, I've been a bit slow in building the dH2 recently. The weather was good for flying so time was spent at the field until my Wot 4 lost the battle with gravity! I got the Chipmunk air-worthy and managed to park most of it 40 feet up an oak tree. The bit which came out of the tree was the engine and its fall was broken by landing in a big pile of sheep poo! The remainder was retrieved subsequently and all the 'bright and shiny' bits will be re-cycled. The workshop is getting a bit cold now, but I have purchased another Chipmunk and have now almost finished building it . The defence rests, mi Lud.

I have managed a bit of progress on the dH2 however.

I have finished the inter-plane struts and trial fitted them. (Note the new Chipmunk, in the background, shielding its eyes from the dH2).

In order the secure the struts to each wing, I got one of these, above......................

.........and with the aid of tin snips,a Dremmel, a small file and lots of patience, converted it into lots of these little brackets which would serve to secure the struts and provide anchors for the forth-coming miles of rigging. A fair amount of fiddling, fettling and cussing later and the upper wing was trial fitted. Above is a close-up of how the the brackets, yet to be 'rounded-off' and 'tarted up' a bit, are employed. A small bolt is recessed into the end of each strut and through the bracket into a captive nut in the under-side of the wing. The whole fitment is held in place with the horizontal nut and bolt, which is also yet to be finished off. The aileron control wire along the leading edge is supported and guided by very small loops bought from a model boat builders shop.

Above is a, slightly out of focus, picture of progress on the cabane struts.

After much huffing and and puffing, not to mention the odd cup of tea and a Biccie, the carbon-fibre aileron 'joiners' are fitted. The ailerons are actuated on a closed-loop system and I'm pleased to report that the servo is 'man enough' to do the job. I'm also most 'chuffed' that the wing incidence is still accurate and the whole structure doesn't show any signs if warping.

That's about it for the moment, Chaps. Happy landings, Roy

[Monz]

This is looking great Roy, really nice bit of building going on here!

[Tony Bennett]

it do look good sir.

[john stones 1 - Moderator]

A variety of skills on display Roy, nice work

I'm going for a cup of tea now

John

[Roy Hill 3]

After rather a long delay caused by life, family, hospital and other reasons, work has recommenced on the dH2. Photographic evidence will follow soon! The motor is fitted and works but a question has arisen to which only the combined knowledge of the readership of this blog have the answer! On a normal 'tractor' power plant a measure of down and side thrust is built in. The dH2 has a 'pusher' motor. I have built the firewall as the plan dictates but it doesn't appear to have any down, up or side thrust! Any suggestions? Happy landings, Roy.

[Dave Hopkin]

In my warped and twisted logic, if the motor thrust line is below the mid inter plane point it would try and force the nose up, therefore down thrust would be needed, as for side thrust I would add a little as the torque effect is still going to be there

[reg shaw]

I've done two DH2's over the years, neither had any down or side thrust. One had a Laser 80 and the other a geared Zenoah 62. Cracking job you are doing of this one Roy

Ian.

[Manish Chandrayan]

Subscribed, can't wait for updates.

Roy what thickness brass sheets did you use for the brackets?

[Roy Hill 3]

Hello All. Thank you all for the advice. I failed to mention that I'm using an electric power plant with reversed polarity thus I can use a conventional tractor propeller! I'm not sure if that would affect any of the advice given about thrust lines. Manish, I've used brass sheets from Precision Metals. Size is 0.010 x 4" x 10". The code is SM2. It is available from most model shops, in UK, but I seem to remember that you live abroad! I will upload some photographs over the weekend. Happy landings, Roy

[Manish Chandrayan]

Thank you Roy. You are right, I am in India

[Daithi O Buitigh]

One thing to be very careful of Roy is that, in running reversed polarity with a tractor prop is that the motor is spinning the 'wrong way' and any threads on the prop adapter will tend to unscrew. Just make 150% certain that they're really tight (and maybe a dab of loctite on it for belt and braces)

[cymaz]

Stunning build

[Roy Hill 3]

Hello Daithi. Thank you for that. Locktite at the high port, Sir! Roy

[Roy Hill 3]

Hello fellow flyers. The saga of the dH2 from scratch continues. What was a pile of balsa, aluminium and wire is now finally showing signs of becoming a model aircraft. Having created and fitted all the plastic and brass brackets etc, to secure the rigging and control wires, the time came to cover the little beauty! It took a week or so. Firstly because I enjoy covering and secondly because I wanted to get it right and Antique Solartex ain't cheap! I'm reasonably pleased withe the result.

I needed to find a method of allowing the strut bolts to penetrate the Antique Solartex without the risk of ripping or splitting. As the Solartex is fabric, I thought of modifying an old soldering iron by replacing the 'bit' with a piece of copper tube. I cleaned and 'sharpened' the brass tube to give a neat cut and got to work.

Once the soldering iron reached operating temperature, I placed it where the hole was needed and gave it 'a bit of a twirl'.

The Solartex heats up, melts the covering leaving a nice round hole and then reseals itself, leaving just what I wanted. The time came to join the wings to the tail! This involved epoxying brass tubes in to the upper and lower wings, ensuring that the angles were exact. Any error would build an unwanted warp into the fuselage. The 4 aluminium tubes, which form the fuselage, were fed into the brass tubes and the angles were checked again. All being well I drilled through both tubes, and secured with a nut and bolt and more epoxy.

Ensuring the tail-post was upright in all planes was a harrowing experience. Much tea and biccies consumed!

The whole model felt a bit flimsy at this stage but when I completed the rigging it became very strong indeed! It took several days to get the rigging right. I've used miniature pullies, (a la full-size) for elevator and rudder control and now they all need adjustment before ground trials commence. (See below)

The Hacker motor was installed onto 4 high-tensile bolts. This option left me plenty of room to adjust the thrust lines. (See previous advice from fellow bloggers).

All the undercart and tail skid, complete with elastic suspension, is fitted and working. I've treated all the exposed woodwork with Teak Oil which gives a nice finish. There is still a bit of work to do on the engine cowling and cockpit but I couldn't resist the urge of fitting the armament and Flying Officer Kite, just to see how it looks. I also need to manufacture some roundels and give the tail fin its colours, prior to the maiden flight. Once the final bits and pieces are done, I will report back.

TAIL-PIECE!

This whole project started with me seeing the plans in a magazine. I down-loaded them, up-scaled them to give me 64 inch wing-span and cracked on with the build. Now, some 18 months later, it has occurred to me that I have dropped an enormous clanger. Because of the rigging, I chose to build it not to be dis-assembled. It's TOO BIG to fit in the car or trailer. Oh Dear, Oh Dear, Oh Dear. Looks like the next project might be building a new trailer. Happy landings, Roy

[Martyn K]

Looks superb Roy.

Very well done

Martyn