The Balsa Channel.

[Doc J]

Hi Guys,
As some may know, I have been working with Andy Whitehead, the head honcho at Angelwing Designs and a fellow Bimey Brit.
Andy designs some of the very best small balsa models available. They are either electrically powered or really kinky balsa gliders.

I have had an idea on this that might be interesting - I don't know.

The first thing I wanted to establish was that these AWD models, past and now being designed and built, are in no way or form any competition to the balsa model stable offered and designed by Aloft—they are different in every way. These balsa models are not sold in the USA, and there are no plans to do so.

Anyway, here is the idea:

I wondered if people would like to see the evolution of a newly designed balsa model from the drawings through CAD, CNC/Laser cutting, and printing of the parts to the fully assembled model and then the flight testing. I.e., the evolution of the original idea to reality step by step.

If that's interesting, please let me know. If not, that's OK, too.

Cheers,

Doc

 

[Hoqiam]

Hey Doc
For those of us who are Centenarians, and from time to time are grounded, I would like to say Please do!
I am building an electric Ridge Runt and have enjoyed the blow by blow build that Wayne has produced.
I also enjoy reading about your active work and what other folks around the world are doing. I sure whish
this kind of help was available back in 1932!

As I am sure you know, producing build manuals, drawings-plans, and associated photos are art forms in themselves
and I enjoy drooling over them almost as much as building the model it's self.

Tom

 

[Doc J]

Hey Doc
For those of us who are Centenarians, and from time to time are grounded, I would like to say Please do!
I am building an electric Ridge Runt and have enjoyed the blow by blow build that Wayne has produced.
I also enjoy reading about your active work and what other folks around the world are doing. I sure whish
this kind of help was available back in 1932!

As I am sure you know, producing build manuals, drawings-plans, and associated photos are art forms in themselves
and I enjoy drooling over them almost as much as building the model it's self.

Tom

Hey Tom - there is a vote of confidence!

I'm not a centegenarian, merely a septegenarian, but like you, I grew up with this stuff, and I'm really glad I did.

It's great that recently, in these days of foam, plastic, and moulded models (I am an offender), Aloft and others are trying to revive what is the root of all our hobbies, and I was glad to have a chance to participate in one of these revivals. In the days of the old, one of the most enjoyable things about the modelling world was to get together like-minded souls and hang out, impart information, tell a few lies, and generally make good, sometimes lifelong friends. At times, the flying bit was almost secondary.

OK, anyway, that's enough for me, so I'll gather the materials, and we can follow the story of the little Aria from start to finish. This small model is a really good example of how plain old balsa bashing has evolved, embracing modern technology into an easy-to-assemble but still fun-to-make balsawood model.

Watch this space.

Doc

 

[Doc J]

OK, let's go.

Obviously, to make any model, you have to know what you want to make and why you want to make it, because everything you do from that point will have an effect.

In this case, Andy Whitehead, proprietor of Angel Wing Designs in the UK, had invited me to sketch a few ideas for conversion into balsa models using my design experience. I was very intrigued by this as I grew up chewing balsa wood. AWD is a commercial operation, so the designs would have to be generally appealing and not weird or "special". So I looked around for a gap in the market—several actually, but we'll talk about one for now.

The model couldn't be too large because Andy generally likes to make smaller, transportable BIBOC models that won't burn a hole in the buyer's wallet. Yet, they should perform well and allow a good measure of that hard-to-come-by commodity -FUN!

So in this particular case, a quick look around to see what was available revealed that a small VTPR (Voltige Tres Pres Relief - Aerobatics very close to the slope) model might fit the bill, and a quick consultation with Andy soon had a general specification on he table:

• 1~ 1.5M span.
• Appealing outline - even balsa can be curvy.
• Light but strong construction.
• Good potential VTPR performance with madstab.
• Possibility to use the wing and tail CAD for other models in this series.

So I put pen to paper with those criteria in hand, and this is what happened: The ARIA 1.2M Balsa VTPR outline was born.

• It has symmetrical wing and tail sections and is intended to be very light—in fact, lighter than a foam model—so it will fly in very light air.
• An AWD-designed madstab will be involved, though it is not on this drawing.
• The wings and tails will be removable.
• The carbon rod or tube wing joiner can be replaced with a metal rod to act as ballast if needed.
• The wing configuration can be full Ailerons, Ailerons and Flaps, or even Wingerons - depending on how the builder wants to configure the model.

From here, I digitally scanned the drawing and passed the scan on to Andy, who converted it to CAD. Andy then commenced the design of a really nice balsa structure.

More next time.

Doc.

 

[Hoqiam]

Hooray! I suddenly started getting alerts!!!
I sure do not understand how or why, but at least something works.

Hey Doc; Off to a great start! I am not a great fan of profile type models but the overall lines are nice!
The cutouts in the wing and stab trailing edges could only be practical with laser tech. but at first glance the resulting diagonals
look very fragile due to the probable grain direction. Since this an actual model I guess it must be ok. I understand the
motive but I don't think I would have tried it! Just for a measure on your thoughts, how much weight did you save?

OK after looking at the TE's another time, I see I could be very wrong in how they are made!

Somewhere along the way i missed how the term "MAD STAB" came about. Can you enlighten me?

Tom

 

[Doc J]

Hooray! I suddenly started getting alerts!!!
I sure do not understand how or why, but at least something works.

Hey Doc; Off to a great start! I am not a great fan of profile type models but the overall lines are nice!

Actually, Tom, it's meant to be a bit flat, not an actual profile, and that's to help (a bit) with knife-edge flying, which, when you think about it, is something no self-respecting glider pilot should ask his slope soarer to do. I think Andy did some tweaking for the actual model.

The cutouts in the wing and stab trailing edges could only be practical with laser tech. but at first glance the resulting diagonals very fragile due to the probable grain direction. Since this an actual model I guess it must be ok. I understand the
motive but I don't think I would have tried it! Just for a measure on your thoughts, how much weight did you save?

According to Andy, about 45% of those components. Remember, here we are going for light, light, light, so hopefully, the kinetic effects of a sudden arrival will not be damaging.

OK after looking at the TE's another time, I see I could be very wrong in how they are made!

Tom

Good stuff - keep the questions coming!

Cheers,

Doc.

 

[Doc J]

OK, we have the outline drawing, and this is where I have to take a bit of a back seat and follow Andy Whitehead's thinking on the balsa design.

It's been a long time since I designed a high-performance balsa glider—back when I did, there was no CAD, Lasers, or plastic printing, and there was no choice! Nowadays, technology has advanced to the stage where CAD, CNC, Laser cutting, and plastic printing are very much involved.

So the first thing Andy did, logically, was to look at the possible wing construction, which gives you that "Half done" feeling. These days, there are many more choices of materials than 40 years ago, so Balsa wood, Spruce and Birch ply are not the only things we have to work with

Andy used Carbon tubes for the main spar and the sub-spar in this case. These tubes are stiff (Notice I did not say Strong), easy to buy, and easily incorporated into any balsa structure with medium-thickness Cyano glue.

Lightness is the order of the day here, so the sheeting was confined to the root rib area where it was needed, mostly for handling. Ribs and sub-ribs make up the main structure. The trailing edge is 1.5mm (1/16") plywood and has not been lightened by laser cutting at this stage.

Notice that all the parts interlock, and due to the laser cutting (AWD uses a very high-end machine), they will be superbly accurate. What cannot be seen yet are the removable tabs on the bottom of the ribs, which act as a jig, allowing the structure to lie flat on the workspace and ensuring a straight-built wing, always a part of AWD design.

Observant people will notice that this wing is not even part of the Aria design. It is, in fact, the same wing and interchangeable with another model that is coming.

So with the basic wing drawn in CAD, it's now possible to look at how to make it better and easier for the builder to get a perfectly interlocking and arrow-straight structure with some of the hard or fiddly bits done on the printer.

Watch for more:

Cheers,

Doc.

 

[Hoqiam]

Hey Doc;

I very much like your text placed below the graphics! This is the more conventional manner of document presentation
that I am familiar with. I like to be able to look at the subject matter while reading about it.

Tom

 

[Wayne]

Sure is a pretty plane.

 

[Doc J]

Hey Doc;

I very much like your text placed below the graphics! This is the more conventional manner of document presentation
that I am familiar with. I like to be able to look at the subject matter while reading about it.

Tom

Old skool! It's in my training, Tom.

At school, later at University, anything technical - writing dissertations and before exams, etc., I was taught to leave a space above and below each line of text and each illustration or graph so that my teacher or tutor could easily add comments.

Anyone who has received any of my emails will find the same thing: I separate each statement or sometimes each sentence. It takes up more space, but it's easier for the reader—or Professor!

Old phart that I am, I never got out of the habit.

Cheers,

Doc.

 

[Doc J]

Sure is a pretty plane.

Thanks, Wayne - I hope it flies as well as it looks, and covering/testing is getting close.

I am quietly confident.

Cheers,

Doc.

 

[Wayne]

Yeah, I think it will go well.

 

[Doc J]

OK, Chaps, here is more on developing this modern balsa/hybrid creation.

Here, we can see further development of the wing. An interlocking centre section/joiner box has been made and fitted that will provide a tough wing root and ensure perfect alignment of all the joining parts.

The ply TE has also been relieved of some weight.

Note the tabs on the wing ribs to allow for a perfectly flat assembly. These are obviously removed after the wing is assembled and before covering.

Andy has now added a small printed aileron/wing TE piece, as some people find this a bit tricky to sand.

Also in the picture are printed flap ends. This method ensures that everything is in perfect alignment. Note the curved piece rising from the wing centre section. This will form the back of the cockpit area. The wing roots /joiner boxes are now covered by balsa sheeting, adding to the strength of the centre section, especially for handling and assembly.

Note that on this model, the aileron and flap controls exit from the wing's upper surface, as on a symmetrical section, this will make absolutely no difference. In fact, it is probably a bit better aerodynamically and less likely to be damaged by landings.

The printed fuselage formers have suddenly appeared, but we'll get to those later.

More next time.

Cheers,

Doc.

 

[Doc J]

Before discussing this model's other components, let's examine the kit's wing parts briefly.

As with all parts of the model, everything is done to ensure the builder's job is easy and results in a good, clean, straight wing.

Here, we can see the super-accurate clean laser-cut balsa, ply ribs, trailing edge, and spar sheets. These are all competition-grade materials from Indonesia.

Printed parts form the wing roots, aileron ends, and flap ends. We can also see the two carbon spar tubes and the white white PE jig plate used to insert the ribs into and assemble the wing.

All of these parts come with the kit. (Not the balsa knife!)

Here we can see the wing construction beginning with the root, spar, and ribs. The root end ribs are slotted together.

The rest of the wing ribs, inserted into the foam spacing jig included with the kit, are below the root assembly.

It's coming together.

Last but not least is the wingtip. Simple block balsa works here. Note the printed aileron/wing ends

OK, next time, we'll examine the fin and tailplane construction again using the jigs supplied in the kit.

Cheers,

Doc.

 

[Doc J]

Hi Guys,

With the Aria wing completed, we can now examine the rear flying surfaces, the fin, and the horizontal stabiliser.

Note that I designed the Aria as a VTPR, and although I don't generally like or use all-moving-tailplanes (AMT), in this case, it has to be that way to utilise the AWD madstab mechanism.

Here are the empennage bits that come with the kit. Again, we can see printed root and tip ribs, nicely laser-cut balsa ribs with assembly tabs, nicely lightened tips, the 'aerated' ply trailing edges, and the PE plastic wing and building jig. And of course, the carbon spar/joiner tube.

The fin/rudder assembly is a little different. Ribs are laminated between two pre-cut balsa sides.

This picture includes the laser-cut fin and rudder laminations, the AWD Madstab mechanism, and two printed sanding guides. The fin/rudder assembly is so simple that it doesn't need a vertical rib assembly jig, but it's a bit hard to build and to sand as all the surfaces are contoured, so AWD have included the two printed (red) building and sanding frames to make life easier. Ribs are not shown here.

The fin is assembled and weighted down between the two building frames to press it all together and make sure it's all exactly straight.

Here, the assembly/sanding frames hold the fins for sanding—happily, not much is needed.

Fin is done. Note, this is a prototype, and the interlocks have now been tweaked to make a perfect fit.

With the fin done, I won't bother showing the rudder as it follows much the same procedure and it's pretty foolproof.

Tomorrow I'll cover the AMT.

Cheers,

Doc.

 

[Doc J]

Its Aria all-moving-tailplane time.

The fin is done so here is a quick review of the tailplane parts.

There is no difference there, and construction follows the usual AWD jg-built procedures.

The same basic steps - place the ribs with the tabs into the assembly foam slots and assemble the parts, and you will end up with something that looks like this - nice and flat despite the symmetrical ribs.

Removal of the rib tabs and a quick sanding of the assembly is needed before a trial fit.

OK, good - it works smoothly with no play.

Mad enough?

One thing to note is that these pictures are from the first cut/prints of all the Aria parts. Since then, EVERYTHING has been tweaked to provide optimum fits and finishes in the final kits.

Next time, let's look at the AWD method of fuselage construction.

Cheers,

Doc

 

[Doc J]

It's Aria's fuselage time.

The parts that come in the box are pretty comprehensive and detailed. They include printed formers, a nose and wing joiner box, all the strip wood, and the control rods and sheaths. The fuselage sides are notched for the printed formers to slot into

The wood is the usual AWD Indonesian-grown, sawn, and dried competition-grade balsa laser cut to great accuracy.

Putting the fuse together is straightforward, and it's hard to get it wrong unless you really try. Triangular strakes are glued to the fuselage outline before the formers are glued in and the assembly is put together.

Don't forget to put in the control rod sheaths.

After that, the fuselage can be closed up with the top and bottom sheets.

A couple of elastic bands or a few clamps, and it's looking good.

Don't forget this bit!

Time for a quick trial assembly. All square and good?

Next time, let's look at the lightweight finishing.

Cheers,

Doc.

 

[Doc J]

Aria 1.2M (47") VTPR Prototype done and ready for test flights at 425g, ready to chuck.

Flight reports next time if the UK weather cooperates, but it's looking good.

So, anyway, there is the start to the finish of this modern balsawood kit.

Cheers,

Doc.

 

[Hoqiam]

Hey Doc;
That was much to fast ! I had hoped for a much more detailed presentation.
Not many people know, but I invented 3D flight. My patents for it were developed during
the 1970--1987 time period. My original mission for this concept (to stall an aircraft on purpose and
still be able to control it) was to recover fixed wing drones into extremely small, unlikely areas, but still
be able to abort the landing if necessary and relocate or delay the event. This was called "Super Normal
Flight" back then. This involved rotating the Horizontal Tail Trailing Edge up to an angle greater than 45
degrees quickly to stall both right & left wings. This would cause the aircraft to go into a nose
up attitude and start de-sending like an elevator. Since the HT was now in a vertical flow field it could
be controlled to modify the motion of the craft forward or backward. Or if desired, it could be rotated
back to it's normal position and return to "Normal" flight.
In my demonstration flights to the military I was constantly challenged to do many things to demonstrate
my complete control of the aircraft. Weather conditions, wind and turbulence, being of biggest concern.
By putting the craft into all kinds of attitudes and maneuvers, then entering Deep Stall (Super Normal Flight)
the craft would always drop into the typical nose up upright attitude. This usually calmed the skeptics. All of
this was to replace the idea of using an uncontrolled parachute.
I did some demo flights for Dale Reed at NASA Dryden Research Center out on the Compos Rose to see if
it might be useful for application to a Mars Lander aircraft. They modified a maned T-tailed full scale glider and
flew that successfully also.
Yes I learned to fly my modified models in what is now called 3D. Since I did my research flights at the local
club field in down town Hampton, VA, I was constantly asked what I was doing, they would say, airplane can't
fly like that!!
Today I can say Yes they can! Just watch a demo flight of an F22.

I am interested in the Mad Stab mechanics. It would be interesting to see how he does it.
In my day I had to modify my TX and use 2 servos.

Hope this little input is not too boring.

Tom

 

[Doc J]

Hi Tom,
To be honest, all of this story is in detailed visual form that is easy to refer to, so I didn't go into too much verbal detail, as many people these days don't like to read long diatribes.

If you'd like more information or a description of any part, or why I designed it that way, I'm happy to oblige as usual. However, for construction, Andy Whitehead is the design genius.

I love your description of the work you have done. It's people with ideas like you who push this hobby forward, and in a good way—although obviously, you were aiming for full-sized applications there. The principle reminds me of the old FAI Fee flight A2 glider "dethermaliser," which did the same job, destroying the flight pattern by tipping the horizontal stabiliser up and putting the model into a deep stall.

I'll ask Andy if he is willing to share tech details of his madstab, but here it is in sketch form.

Cheers,

Doc.