A Trio of MD Helicopters

[Rizon]

A Trio of MD Helicopters

I have always been fascinated by the NOTAR helicopters that Hughes, and later McDonald Douglas, developed and finally brought to production in the early 90’s. The fascination even went that far that I ended up doing most of my undergraduate and all of post graduate studies on a similar system (that specific one called CIRSTEL) and helicopter aerodynamics.

Thus a NOTAR helicopter was always on my must build list. Some years back I got hold of the Italeri AH-6 kit, with all the intention of converting it. What held me back was the canopy: the kit had of course the original round canopy of the original AH-6, and not the pointed one that is used for the NOTAR versions. About 5 years back I had a try at the kit, having built myself a Mk1 vacu-former. But the attempt at forming a canopy was less than brilliant. The remainder of the parts however came out great. But the canopy issue stalled the project....

Fast-forward 2 years, when I happened upon the AZ Model kit of the MD500E at an airshow. The picture on the front showed the canopy I needed, so I bought it. Big surprise when I got home and found out 2 complete model kits inside. Now I had 3!

Bad news was that the canopy was not completely useful. First it was a model of the fragmented version, that could be fixed though. The big setback however is that the canopy fits badly. Useable, but not ideal. Circumstances at the time caused the project to be shelved regardless.

With my previous build of the Chengdu F-7, I built a new vacu-former, and along with much better knowledge and experience, I tried again at forming the canopy. This time rot useable results, though the master required a bit more work. But now I got a useable canopy, and can continue.

But what to do with the other kits? Simple, build all three current versions of the venerable Model: MD530F, MD520N and MD600N.

Here are all the kits together

And this is how far I got with the first one, the Italeri kit:

Here a group photo of the evolution of the vac-formed canopies. Furthest one was formed in sections (not that great), and the closest two are useable, all formed in one piece.

I formed the plug from Fimo, as it is easy to form and can be easily be carved and filed after being baked. Getting it to the correct and symetric shape is a mission in its own! Caution however, since it attacks plastic if left to contact it for too long. This is what a sheet of PETG looks like when formed over the plug.

Now proceeding with building, I decided to use the Italeri kit for the MD600N conversion, simply because the port door was moulded separately, which made cutting the fuselage into a front and rear bit to accept the extension piece much easier. This is after cutting it, and with the extended floor and overhead spacer fitted.

Next up the production of the extension piece doors and fuselage skin.

R

[heloman1]

Intersting conversion Rizon, I've looked at this myself a couple of times but that was as far as I got... I'll follow your build with interest.

Colin

[perdu]

me too, NOTAR has always fascinated me too

[Dermo245]

Very nice work!

[k5054nz]

I'm working on a Profiline MD520N and it's a great way to get a NOTAR out of the box, although a clear fuselage "egg" is less than ideal to work with! I've done half a dozen 1/72 500s but I'm not game enough to try a 600...bravo! I'll follow this with great interest.

[Rizon]

At one point I tried to get hold o a Profiline kit. But to no avail.

I like the idea of the clear fuselage parts, put have read they a a bit thick and difficult to assemble. But best of luck! Post some photos sometime!

R

[HOUSTON]

Nice work..

Look forward to this ...

[Blue Monday]

Good luck with the three models, in particular the MD600N.

BM.

[Rizon]

Progressing a bit slowly lately. Too many other distractions this time of year....
Got a bit done today though, before heading to the farm for the next few weeks for the summer holidays. :-)

Started working on the rotor for the MD600. A 6 blade rotor is required instead of the usual 5 blade rotor. I made an extra blade from the sprue of the Italeri kit, as I wanted to keep the same stiffness in respect to the other blades. Sheet styrene would be too flexible in that thickness. The sprue also was of the convenient correct width! The blade root detail I made from styrene rods and stretched sprue. Also started to add the lead/lag dampers, which are not moulded on the kit and then thinned the blades down a bit. Finally I added a tip extension to the kit blades, as the diameter of the MD600 rotor is bigger than the MD500 one. Now for the remaining blades....

R

Edited December 19, 2014 by Rizon

[Rizon]

Summer Holidays are somewhat of a memory now, and only managed to do a little bit of modelling.

Mostly been sidetracked with test flying UAVs, designing them and evaluating a Masters thesis on them..

But this is what I got done:

Rotor blades have all been lengthened and the thickness reduced a bit.

And also started on the hub, loosely based on the kit part and built from styrene pieces.

An then I also completed the stretching work on the fuselage for the 600. Underneath the floor I installed a bit of lead, I suspect this one might otherwise turn out a tail sitter.

And the completed "sheet metal work". I simply used very thin styrene sheet; installing it by bending and glueing it in place.

R

[Blue Monday]

Nice work on extending the fuselage and blades. The rotorhead looks good too. Keep coming with the updates.

BM.

[milktrip]

A great project. Keep us posted.

Knowing how small these kits are in 1/72 makes the work you've done even more impressive.

Probably a good idea fitting some lead. You obviously have enough space in the cavity there but for small helicopters like these where there is not much space to fit weight, I tend to use a tungsten putty (bought from a fishing store, used for weights) - It is useful as it can be squeezed and shaped into small spaces.

Cheers

Aaron

[Rizon]

Progress is at a snails pace at the moment.
I take the hint..... :-)

Tungsten putty? Never heard of that before... Will have to investigate that, sounds very useful!

R

Edited February 16, 2015 by Rizon

[Rizon]

Slowly the worm is turning...

Installed the cabin roof windows on the extended section and started to cast seats for the pax. Since this is an easy shape, I simply used epoxy glue to cast the components. Works well enough. And then I replaced the main rotor shaft with steel wire, firmly embedded in the kit part that forms the base of the shaft. Don't want this thing to break off! Of course the shaft still needs some trimming. But I'll get there....

R

Edited February 24, 2015 by Rizon

[Dermo245]

Considering the size of this kit, this is amazing work!

Dermot

[Rizon]

I seem to have had a slight bout of Modeler's Block. Was getting stuck down with details that got me nowhere. But I think I am better now....

Still mainly working on the MD600 for the moment. I vacu-formed the fan housing and intake duct:

Cut out and glued together it looks like this; the big gab is my fault from trimming the part out from the sheet.

And then provisionally put in place, with the intake opening cut out:

R

[milktrip]

Glad you're over your modellers block, I know what you mean.

Good progress, I really enjoy WIP threads like this. You learn a lot from them.

[Blue Monday]

Progressing nicely.

BM.

[Rizon]

Latest bit of work on the MD Helicopters focused on the NOTAR intake and fan housing.

A big part of the recent effort went to the styling of the intake. In particular the inside of it. In retrospect, I should have made a new master for both the housing and the intake duct, but in the end I got to where I wanted using bits of sheet plastic, epoxy and putty.

For the fun of it I also built a fan. The 13 blade fan was sketched up in CAD and printed on paper. Didn't realize the lines would come out that thick, but then again, the part is very small. I used a scalpel to cut the part out, then twisted the blades a bit and sealed it with superglue.

And then I installed the fan in the housing. Not that one sees much of it in there. But it is there at least...

And the photo shows that a bit more clean up is required to sort out blemishes on the housing of course.

The hole at the tip of the nose bullet is for the drive shaft, which still needs to be installed.

The tail feathers have these external stiffening ribs. These I added to the scratch built horizontal and vertical stabilizers using heat stretched sprue and tacking/welding them in place with Tamya extra thin glue. That is a lot of work, so I decided to make molds from them for casting epoxy copies....

The masters ready for the silicon molding process...

R

[Rizon]

I am now done with the fan housing and tail booms for the two NOTAR versions. Mostly happy with the way they turned out. Next up is a base coat to highlight and then eliminate the blemishes on those parts. Also started with the nozzle assembly for the MD600. The same part for the MD520 I completed already when I originally started with the conversion.

And I got the molds for the tail feathers. That is the blue thing in the picture, with the masters lying on the silicon mold. I make the parts using epoxy glue, thus there are no real casting holes in the mold. To inject the epoxy I simply peal open the mold, apply the epoxy and close it. The high viscosity of the epoxy prevents any leakage, but is still sufficient for the epoxy to flow into the mold. To some extent at least. In the minute or so before rapid curing sets in...

Plan on doing the casting this evening....

R

[milktrip]

Good luck with the casting. That NOTAR fan looks absolutely brilliant.

Do you find epoxy easier to use than resin? I've bought myself a resin casting kit as I'm wanting to start casting my own bits and bobs, just wondering why you use epoxy.

Cheers

Aaron

[mirageiv]

[Rizon]

Good luck with the casting. That NOTAR fan looks absolutely brilliant.

Do you find epoxy easier to use than resin? I've bought myself a resin casting kit as I'm wanting to start casting my own bits and bobs, just wondering why you use epoxy.

Cheers

Aaron

Epoxy is not easier to use than resin - just a heck of a lot cheaper. At the moment I only intend on casting very small bits in very limited quantities, and thus I can't really justify buying 1 kg of resin (1 kg is the smallest amount I can get here). Resin flows better, so I'd say it is better to use it, especially if small details are required. But for a quick "DIY" type of casting, the epoxy glue does the trick. Also the epoxy (at least the one that I use) remains quite flexible for a few hours after setting, which allows one to extract it from the mold without worrying of breaking it. The part will then return to its intended shape and cure properly.

R

[Rizon]

A Summary of my exploits over the long weekend:

Got around to experimenting with casting a bit. As I already mentioned, due to economic reasons I use epoxy at the moment, which works quite well actually, if one works quickly. And on a trip to the Hardware store to buy some tools for the house, I came across a slow setting epoxy glue. They say 6 hours on the box, but realistically more like a 1.5 hours for it to be workable. Not that it matters, that is plenty. So here is what came out of the molds. Flash provisionally removed but parts not cleaned up:

the white parts are from the usual epoxy I used and the clear-ish parts with the slow setting one. All-round quite acceptable. The bubbles in the clear parts are in the part, the surface is clean actually...

The pilot figure is an assembly from different masters, body from one, head from another etc to make up a civilian pilot. Also added some small lead shot to the casting of the pilot, so that the figure can act as a nose weight.

Oh, and the nose gear is a copy of the Italeri Hawk for the Airfix kit. See Fritag's Hawk thread if you are wondering why....

And then I concentrated on the tail thruster assemblies for the two NOTAR versions. This mainly involved adding details such as the guide vanes and the rotating can through which the amount of thrust is regulated:

R

[Fritag]

Love all of the scratch building/moulding/casting you're doing R. Really enjoying this build