Functional hardware fittings on scale models
 

I'm new here... what the heck, going to start a new post.

I really like the recent threads which were started along categories of rudder construction, spar, wheels, etc.
My recent obsession has been about the various hardware bits used on antique aircraft, and how to use these same methods to build models. Particularly, about how to do cable braced fuselage, wing etc.
I ran across a diagram of some of these fittings on wwi-modeler, and am really fascinated with the idea of building a miniature wwi aircraft in the same fashion:
http://www.wwimodeler.com/harry/chap...4-skeletal.htm

When I saw this picture of an undercarriage posted in this forum, I was in total awe of the hardware fittings used-
http://www.rcuniverse.com/forum/upfi...35/Pn37919.jpg

If anyone wants to divulge tips on how to do this kind of detailed, functioning hardware, I am all ears. I hope it does not require sophisticated tooling to produce these hardware bits, IMO they really make the model.
Anyone want to show off and describe any cool hardware bits that they have concocted for their miniature aircraft?

One more related thing... I have heard that the Proctor E.III fuselage is built/braced like the real deal. I read a comment about these so-called brass 'star' fittings used on Proctor E.III and wondered if anyone had seen/used these fittings and would be willing to comment about how they work.

RE: Functional hardware fittings on scale models
 

Welcome to the forum -- we can always use another WWI enthusiast!!! The problem with attempting to use scale functional wire bracing is that to make it really functional you'd have to be using a gazillion functional turnbuckles on the wires. The three techiques I've see to simulate the wires on a model are 1) rigging thread 2) bamboo dowels/skewers (used on my Nieuport build) and 3) bits of wire (that's what I used on my EIII fuselage).

I'm also interested in scale fittings and I hope this thread results in some interesting ideas. Donnie (the builder of the Jenny UC you show) is certainly a master of little metal bits and bobs. Actually, I think a lot of "metal" parts can be faked with either styrene or bits of aluminum tape.

I think often all you can really do is go for the effect and try to follow your documentation photos as closely as possible. Here's a photo of the rather complex UC on my EIII which I think looks pretty darn close to the San Diego replica I was modeling. The wooden fairings are made of balsa soaked in CA for strength, primed and painted. The "straps" are just bits of FliteMetal wrapped two or three times. Short of using an entire machine shop to custom machine parts I think this is about as scale as anyone is going to get with EIII gear.

RE: Functional hardware fittings on scale models
 

BTW, I don't think I'd call the Proctor EIII fittings scale but rather "scale like." Even the fancy "Fokker style" bolts they sell aren't actually shaped like the originals. For that matter the shape of the Proctor turn-buckles are also not like the turnbuckles used on original WWI era aircraft (they're too thick to be truly scale). The point here is that ultimately a completely 100% scale sctructure is probably unobtainable. All we can do it get the effect right. Donnie's models are certainly an inspiration.

RE: Functional hardware fittings on scale models
 

Abufletcher,

I am quite familiar with your E.III project. I followed a lot of your discussions, from which I got very good information about WWI era structures that I applied while building the plane shown in my avatar. Good job on your Eindecker... I more fully appreciated your detailing efforts after I got the FTS CD with all the pictures of the San Diego replica!

Now I was comparing the pictures of Donnie's JN4 (posted in [link=http://www.rcuniverse.com/forum/Spoked_wheels_%2D%2D_no_soldering_needed%21/m_2693952/tm.htm]Spoked wheels -- no soldering needed! [/link] ) to some JN4 photos on WWI-Models site ... and I got to noticing all the brackets holding everything together. These brackets reminded me a lot of the Angle Plate Joint (diagram B) shown in the [link=http://www.wwimodeler.com/harry/chapter3/04-skeletal.htm]Joints-diagram on wwimodeler site[/link]

As an aside, I heard somewhere that the hardware fittings help hold the longerons, cross-members etc together thanks to the tension on the cables - necessary to design fuselage held together by wire bracing because the available adhesives were not up to task. It seems to me that it would be important to minimize drilling or screwing through the framework, to avoid weakening the wood members. Seems like you might even need to sleeve the bolt through holes lest they get "wormed out". If not bolt through, I suppose wood screws (for smaller attachments) or lag bolts (for larger load-bearing structures) would be used. Has anyone applied these considerations to their models?

Wait, I'm not done... more questions! Can anyone point me to any additional photo or description of how the "Angle Plate Joint" is attached to the cross-members? It also appears that the "internal" brace wire in [link=http://www.wwimodeler.com/harry/chapter3/04-skeletal.htm] the diagram[/link] is somehow attached to the bottom end of the bolt that goes through the top of the Angle Plate Joint. An eye-bolt perhaps? I thought about doing a fuselage which would use Fireline for functional bracing. Maybe I could even get by without turnbuckles. I just wanted some simple, somewhat authentic way to attach the Fireline "cables". I might consider fabricating something like the "Angle Plate Joint" out of thin metal sheet.

Finally, I got to ask one thing about the JN4... I noticed in pictures (both of model and of full-scale) what appears to be wrappings of thread or chord around the undercarriage struts. The JN4 strut appears to be entirely wood (as opposed to wood fairing strapped to tubular steel strut). Is the "wrapping" around the strut designed to prevent the wood strut from splitting along the grain?

Thanks in advance for your comments!

RE: Functional hardware fittings on scale models
 

All interesting ideas. Again unless you're talking about AT LEAST 1/4 scale and probably larger I don't think actually reproducing all the functional metal brackets would be realistic for a flying vs. static model. And you're talking to the king of unrealistic builders here! :D

Here are a couple of must see sites. The first is Donnie's build of the Jenny over on rcscalebuilder where all mysteries (well most of them) will be revealed! The second is Achim's ongoing documentation of his full scale flying replica of the DVII. It's a treasure trove of info on small metal bits.

http://www.rcscalebuilder.com/forum/...005&PN=1&TPN=4

http://www.theaerodrome.com/forum/sh...&page=67&pp=10


Do you have particular project in mind?

RE: Functional hardware fittings on scale models
 

And I'm pretty sure all those nice fastenings and screws would be too monsterously large on anything but a mammothly large scale aircraft. Mick Reeves sell some really teeny self-taping screws but even those are probably too large for true scale. But they can provide I nice "look."

RE: Functional hardware fittings on scale models
 

Very interesting thread here! Only recently I discovered an alternative use for solder lugs as attachment points for wire bracing.

I used some in the cockpit area of my EIII in an effort to improve the scale illusion/

The double sided ones could make for ideal 'junction' fittings, i.e. where formers and stringers join and the wires have to be anchored.

Btw mustang, in case you have any models you'd like to show off, by all means!:D

RE: Functional hardware fittings on scale models
 

Trev,
those solder lugs look to be a very good solution... didn't realize there was such a thing! (Still trying to find them.)

Abufletcher,
Thanks for the pointer to DonnyW's Jenny build thread. That was just the sort of thing I was wanting to look at. BTW, I knew Achim was documenting his replica somewhere... but could never quite find it so thanks again for the link.

What I am thinking to build is one of the old monoplanes like the Pfalz or Morane Saulnier, and attempt to build it in a fairly authentic scale-like fashion. The model probably won't be specific, as it is likely to be more of a prototype where I use a hodgepodge of building techniques which interest me. Most particularly, to use all spruce and ply construction much as a full-size vintage airplane, including functional bracing. So the 'junction' fittings are important bit for me to work out. Also want to try a scale wing section with built-up ribs... doesn't look to be too bad of a job really. Would also like to build the wingn with a wire trailing edge.

I intend to use the pictures and 3-views from the Pfalz and MS-L Datafiles as reference to draw my own "plan". Unfortunately these Datafiles don't seem to provide much in the way of actual dimensions... but I suppose that for the majority of antique aircraft it is simply impossible to verify the actual measurements. Going off the 3-view wouldn't be so bad... but important info like angle of incidence, or airfoil type, is not to be found! (Does anyone know the actual airfoil used on the Fokker E types?)

RE: Functional hardware fittings on scale models
 

I developed some hardware on this model using a lot of ideas generously contributed by folks on this forum.
I'll point out the bits that I did on this plane in case it gives someone a good idea.

The control surface hinges are straps of thin brass sheet wrapped around the leading edge of the elevator (and rudder) which is aluminum tube. The tube acts as a joiner for the elevator halves. The trailing edge of the stab is reinforced with 64th ply, and the straps bolt through the trailing edge of the stab using 00-80 hex bolts from Microfasters.

The tail skid swivels and tilts (but is not controlled). Skid is sprung with a spring, not bungee! The "shoe" is a piece of brass fastened with a bolt. THe skid tilts on the brass tube post using a bracket made of thin guage steel snipped from a paint roller tray. A bolt holds the steel bracket to the skid. The brass tube is drilled through such that the steel bracket is retained and allowed to pivot on a A piece of thin music wire. I may have a picture of this before covering....have to look for it later.
The tail is braced with Fireline using AL tube for ferrules and fish-hook eyes are used as attachment points.
I have more pics of the front and the UC parts, but I'll have to hunt for them at home. Anyway, none of this very "scale", but I think it looks cool!

RE: Functional hardware fittings on scale models
 

Mustang,
Nice model! It's got that vintage look to it, even if it's not scale it looks like it could've flown sometime during the 1920's.
It would seem you've put a lot of work into it, any pics of it 'in the bones' would be appreciated I'm sure/
I'd also be interested in the specs.

> (Does anyone know the actual airfoil used on the Fokker E types?)


I've bascially used the same scale airfoil that Art has on his big 1/3 E.I (a proven flyer)
To adapt it more to the E.III one I made the LE slightly thinner...I also included the rib cutouts (eyeballed from photos) to allow clearance for internal bracing. I'm sure there are small discrepancies but it's good enough for me:D

Anyway, here's the E.I airfoil Art kindly sent me.
I've also included a pic of my E.III wing (1/5 scale)

RE: Functional hardware fittings on scale models
 

Trev, well I'm not going to say if for the hundredth time...Oh HECK...what outstanding work on that wing!!! I'm feeling motivated to at least have a scale undercambered airfoil on my Nieuport! The compass housing looks good. Are you going to put a functioning compass under it. That was one of those details I was going to do but never got around to. :D

How about some close up shots of those attachment points? Or you could just make it convenient and put ALL those lovely construction photos in one thread! ;)

RE: Functional hardware fittings on scale models
 

Cheers Don :D

The wings were a part of the model I thought I'd do up as scale as I'm capable of. Not entirely consistent with the rest but oughta give me plenty of practice for future models.

I'll do that thread, rest assured, but as we're talking fittings, might as well include a pic or two here.
The internal wing bracing is not steel wire, instead I used a sort of braided nylon thread (dipped into silver paint) that I deliberately did not pull very taught (in the interest of wing warping).
The attachment points are simple bits made from 0.4 mm sheet aluminium and attached to the ply spar webbing with a small bolt (CA'ed in). The thread was also just CA'ed onto itself/ no crimping of metal tubes. No real attachment points at the anti-compression bars...just routed through.
Rather crude actually, but simple to make. (Bear in mind it's just the 'shine-through' effect with the transluscent covering I'm going for)
I'll also have to dissapoint you on the compass...wont' have an actual functioning one. I printed out the 'bamberg' compass photo you sent me to a corresponding size on photo paper.
I then tried to creat the illusion of an inset compass using a combination of painted ply, small bolts and PET-bottle plastic. Looks okay from a distance.
Sorry for the bad pics...somehow can't get the macro to work on the !#$ camera.

RE: Functional hardware fittings on scale models
 

Trev, as long as you've gone this far, you might as well add the in-and-out fabric that criss-crossed the length of the wing. It would weight next to nothing (bits of black crepe paper might even work) and would make the wing look even more fantastic and even more authentic than it does now.

The compass really does look good! I'd say it's time to start getting some covering on that puppy! Remember that according to Dave Platt once you've covered the model you're exactly half finished!!! :D

RE: Functional hardware fittings on scale models
 

Trev,
That wing is real nice, I appreciate the attention to all the detail of the rigging. I will second the vote for doing the reinforcement webbing in the wing!

Are you implying that then that there is a difference between E.I and E.III airfoil used? I don't doubt that there is a difference, as Fokker and other designers were surely experimenting with the shapes on a continuous basis in those times. I found only one reference about [link=http://people.bath.ac.uk/en3hea/page2.htm]early airfoil designs[/link] but I have not been able to find anything on the German aircraft.

RE: Functional hardware fittings on scale models
 

Mustang, that's an interesting web site. I have been noticing that many of the WWI airfoils had a decidedly sharp leading edge. This is noticeable on both the th Nieuport and the Pfalz thought neither of these had a supper thin airfoil -- certainly thicker than the EIII. I'm trying to decide whether to go with a 100% scale airfoil or use a modified flat-bottomed airfoil. The scale enthusiast in my knows which way he wants to go but the side of me that actually has to do the building and flying says otherwise!

RE: Functional hardware fittings on scale models
 

Thanks! Exactly the look I was going for. I originally wanted to build a scale Pietenpol, but it turned into a hodgepodge instead.

About the model... this model has a span of only 36", it is powered by long-can 400 electric mounted to Mini-Olympus gear box. On 9.6 volts provides more than adequate performance for "scale-like" flight. (If you have never heard an electtric model flown on the Mini-O...some folks complain about the noisy gear box, but it actually makes IMO a pleasant "engine" sound). Prop is 9" diameter. AUW ~29oz. I think wing loading worked out to about 16oz/foot. The model flew well, but sunk quickly at dead-stick and needed to be flown in to landing pretty fast. Gear placement worked well and did not have too much trouble with handling or nose-overs.

I have a couple of pics "in the bones" but they are pretty lousy. Nothing remarkable about the construction, it is basically slab-side construction of front of 1/16" balsa, with the rear fuselage being an open truss constructed of 1/8" pieces. The vertical tail outline was achieved using 1/16" balsa laminations.

The cabane struts are spruce, glued into the fuse, but attached to the wing by 2-56 bolts into blind nuts in the wing. Landing gear struts are spruce, attached to fuse by small steel brackets and #0 screws. Landing gear is sprung with bungee cord.

Hmm, let's see what else. Wing struts are basically just for looks, they are aluminum tube with 1/8 dowel inside for extra rigidity. The attachment points are simply #0 screws through the flattened ends of the ALuminum tube. Problem with this is the Aluminum could bend or break very easy on then ends. The "outboard" aileron placement was achieved using a centrally mounted servo acting through wire links and bellcranks.

RE: Functional hardware fittings on scale models
 

I found some good reading that answered a bunch of my silly question about aircraft materials structures and design -
The [link=http://www.auf.asn.au/scratchbuilder/contents.html]Scratch Builders guide[/link] furnished by Recreational Aviation Australia Inc. Unfortunately, the site seems to be down half the time.

Note: Chapter 12 of the Scratch Builders guide makes reference to FAA publication AC 43.13-1B Chapter 7 'Aircraft hardware, control cables, and turnbuckles' ... the URL is broken, please use the [link=http://www.auf.asn.au/constructors/AC43-ch1_1.pdf]correct URL to Chap 7 of AC43.13-1B[/link] It contains some diagrams e.g. turnbuckle safety wiring which may be of interest to some uber-scale builders.

( I also found a direct link to the entire [link=http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99C827DB9BAAC81B86256B4500596C4E?OpenDocument]AC 43.13-1B Aircraft Inspection and Repair [/link] )

Enjoy!

RE: Functional hardware fittings on scale models
 

I'm sure you guy's are all aware that Proctor offers lots of hardware. Their catalog is really nice if you don't have one you should get one, they have line drawings of their hardware. I was once going to use the smallest turnbuckle they offered to make my Strutter more scale-like but found that strength becomes an issue. The littlest brass turnbuckles look good but are not really meant for flying wires and landing wires...the high stress areas. Once again it becomes necessary to choose between something that looks really great and something that will actually be functional...I have seen somewhere that you can use only the turnbuckle body with a wire through the center, attaching the cable to the wire on each end you have what looks like a turnbuckle but it's as strong as the cable, can't be tightened though....

Randy