JD-2 Dyke Delta - FOAM Build - Version 1

bweaver · January 21, 2019, 11:42:16 AM

While being unable to attend this months build class, I thought I would share what my next FOAM 'stand way-off scale' project will entail. (Yes, @Frank v B , it will be made of foam and other composites and materials.)

I am going to construct the main 40 inch span wing core out of half inch blue foam. The remainder of the aircraft's frame and structure will be built out of a variety of foam type materials, along with light ply and very little balsa, if any.

I have found plans for a balsa 40 inch built-up JD-2 model on the internet, that I am going to use as a guide to help me along with this project. To further assist me I have also found where some other modellers have constructed this and similar models while also using foam. That's right Frank, I am not alone.

Further, I will not be ashamed to copy or extract tips from others past experiences, knowledge and building/construction techniques. Isn't that what is all part of this fantastic hobby?

~~Unfortunately~~ However, due to my current circumstances I am unable to start the construction project (except for in my mind) for at least another 3 or 4 weeks, but once I do, I will post the progress as it proceeds.

piker · January 21, 2019, 03:25:38 PM

Very cool. Looks like a Warwing!

sihinch · January 21, 2019, 05:03:25 PM

Good luck Bruce! It's a cool project.

Frank v B · January 21, 2019, 08:24:23 PM

Bruce

re: "That's right Frank, I am not alone."

You miss us already!! Poor Katie!

It is interesting that the photo clearly shows reflex in the outboard wing panels. When Dr. Keith Shaw did a presentation at the EMFSO AGM wwaaayyy back, he mentioned that the Northrop flying wing (YB-49) had 7 degrees of wash-out at the tips. Interesting to see the reflex airfoil in the photo of your delta. Don't forget to add it if you don't want the elevons to have about 4 degrees of "Up".

The washout in the wingtips is visible at 1:32 and 1:51 run time https://www.youtube.com/watch?v=kuIFvNA1UgU

Happy dreaming and building.

Frank

bweaver · January 22, 2019, 10:29:44 AM

Still thinking!

bweaver · February 20, 2019, 02:05:24 PM

Back to reality and the cold and snow. It truly is great to be home. I only miss the WARM sun and the soft clear blue water.

As previously mentioned I have found PD full size plans through Aerofred. I downloaded the file and took it Staples where they printed out the full size plans at a cost of close to $l0 per sheet and a $3 set up fee. So for $23.52 cents I am set to go.

Now I have to go around my house and find all the sheets of foam I have hidden for some time behind furniture, wall units, in closets, etc. Once those have all been compiled, it's time to start building.

bweaver · March 29, 2019, 08:28:52 PM

SOME HISTORY

The JD-2 Dyke Delta is an American Homebuilt aircraft designed in the United States in the 1960s and marketed for amateur construction. It is a monoplane with retractable tricycle undercarriage and seating for four. The wings can be folded for towing or storage and hinge upwards to lie flat above the fuselage, one atop the other. Construction is of SAE 4230 grade steel tube framework with fiberglass and fabric skins.

For more information about the original JD-2 Dyke Delta go to Wikipedia at https://en.wikipedia.org/wiki/Dyke_Delta

SO THE CONSTRUCTION BEGINS

As noted at http://temac.ca/smf/index.php/topic,6918.msg45826.html#msg45826 , I have decided to build 2 versions of this plane. (Just to see if I can) This topic will now be dedicated to the construction of Version 1 only.

Version 1 – Is going to built with our Warwing standard half inch blue foam, using blue foam for a flat wing, blue foam boxed and shaped fuselage, etc, and

Version 2 – This version will be more complex than version 1 and will be constructed at a later date and under another topic. Version 2 will be constructed using a combination of different foam materials making a built up wing, fuselage, Depron covering and other materials as I had described to those attending last nights build class.

Out came the scissors and one set of the plans was cut up for use in making full size templates.

The wing was cut out from a 2 X 8 sheet of ½ inch blue foam using the paper plan template for this purpose.

Two fuselage sides were cut out using the paper fuselage plan templates. (Note that many individual pieces on the plan can be kept as one larger piece.)

Then the elevons, vertical stab and rudder and so on...

As the construction proceeds, feel free to comment. I know some won't hold back. It was the comments and suggestions from the last build class that have encouraged me to proceed in this manner. I will always find them welcome.

Next to come: Begin gluing.

sihinch · March 30, 2019, 10:21:48 AM

Way to go Bruce. It reminds me of something from Star Wars movies!

bweaver · April 01, 2019, 03:50:13 PM

I took a trip to the local hobby shop to get piano wire for making the landing gear. The landing gear is going to be tricycle type with a steerable nose wheel. I made the landing gear for the rear wheels. (The nose wheel will be made later and the rear set installed after the top of the fuselage is finished.)

I went through my supply of motors from previously crashed or decommissioned aircraft (you choose the terminology to suit your imagination) to find something suitable for this aircraft.

I have selected a Durafly Bravado motor and ESC. I will likely use a 1600 mah 3 cell battery.

I installed some of the electronics. This included the two elevon servos, ESC and receiver.

The rudder servo and control rods for all control surfaces will be installed before closing up the top of the fuselage.

I am using Bob Smith Foam Cure (clear glue) for attaching foam to foam.

I am using Gorilla Glue for securing the wood components to foam.

I took another trip to the hobby shop to buy 1/8th inch ply. (There can never be too many trips to the hobby shop.)

Using the plan's paper templates, I cut out and installed the 1/8th inch ply firewall to the fuselage/wing. The motor mount will be built out from the firewall to accommodate the motor's proper distance for prop clearance and for centering.

I cut out the plywood and foam components using the paper cowl templates for making the engine cowl. There is a 1/8th inch ply component at the rear of the cowl, that I will use magnets for holding the cowl to the fuselage.

I am building the engine cowl before constructing and shaping the front portion of the fuselage. (I think it will be easier to shape the fuselage to the cowl than making and shaping the cowl to fit the fuselage.)

@sihinch After cutting down and sanding the cowl to shape, do you think I will have shaping lines left to worry about? If significant shaping lines are evident, I think I am going attach a skin of fine/thin Depron to make a smooth finish for the cowl, to hide them.

sihinch · April 01, 2019, 03:54:40 PM

Hmmm. Good question Bruce. For some reason, on the rear boosters, I have no layering-lines. On the nose, I do. Maybe it's something to do with the layering direction? It could be that I used epoxy? Or maybe it's me, rushing.

I would say, go for it, Bruce. I'm sure you can get a smooth nose!

piker · April 01, 2019, 08:56:26 PM

I say keep the glue away from the top surface that will be sanded and you'll avoid glue lines. It's the hard glue versus the soft foam that creates the ridges.

bweaver · April 03, 2019, 04:13:07 PM

I shaped the exterior of the cowl. It has glue lines, so rather than spend time on fine sanding; I am going to cover the rough shaped cowl with Depron.

I have cut out the interior core of the cowl using a drill and hole cutting tool. Then it was further shaped internally using a knife and Dremel shaping tool. Similar to what Rob Pike suggested, I had sparingly used glue only around the perimeter of the cowling, knowing that most of the interior would be removed.

Fuselage/wing fairing framing was added for shaping the fuselage and wing fairings on the top of the wing.

Paper templates were made for sizing the fairing covering.

Then the Depron covering was cut using the paper template and the Depron was attached to the wing/fuselage.

In the last photo below, the cowl is just taped to the plane. It will be covered with Depron as previously noted.

bweaver · April 11, 2019, 10:11:45 AM

Construction continues. I think the photos are self-evident as to what I have been doing.

octagon · April 11, 2019, 02:39:19 PM

Looks very interesting Bruce. You should have brought it for show and tell.

bweaver · April 17, 2019, 06:19:43 PM

Still at it.

I want to have it finished to bring to next Wednesday's "Get Ready To Fly Night'.

I started applying a white finish covering using something similar to solar film on the bottom of the fuselage and the vertical stab and rudder. I didn't like how it was coming out, so I have abandoned that approach and have started painting it instead.

When it is finished, the 50 - 50 rule to apply.

I have yet to figure out how to attach the cowl and where to provide a hatch for installing the battery. Tomorrow's challenges.