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D-III VeeBee
With the Ductling D-II prototype static model contributed to what might be feasible.
This provide new forms of construction with foam plastic call DEPRON, commonly used
for fast food take out also foam trays from supermarkets. I collected them over time,
providing me the base material from which I built the Ductling D-II. The model looked
good enough to actually install the components in attempt to fly it. Fans units,
receivers and servos. Where installed and I decide to take it out for a test spin.
I quickly discovered that the model was not properly suited for the fan units. The
"Duct Vanes" where not to specification for the fan units, thereby rendering the
thrust ratio inadequate on the Ductling D-II.
So... The D-III was the next step of development. My first plan of attack was to
rework the detail, but this can be an expensive venture with materials costs. I decide
to build out of construction paper, the kind you use for crafts. New drawing were
created and I began to build with construction paper. Several model where made, each
overcoming a problem as new discovery emerged.
The paper models
Model 1 was similar to the Ductling D-II prototype. Model 2 was what I though was an improvement on the cockpit. Model 3 was an attempt to shorten the ducts, turned out too short. Model 4 I believe to be the final working design by keeping simple geometry. I was able to overcome the difficulty of building the cockpit by using the facet design, making this possible, also adds to an interesting result. The Ductling D-II in its transition to becoming the D-III VeeBee.
Duct Vain
A look at the "Duct Vain". These ducts where constructed with construction paper first. The tubes are made by wrapping the paper 3 layers onto a solid 1" dowel after soaking it in 2:1 water and carpenter glue mixture. When the paper dries it is quite strong and light. This method of construction proves to be a good candidate for other applications.
After building the small model with the construction paper I discover this was suitable for larger scale, so I began to build, to scale of the 55 mm fan unit. Modifications where made to the fans, removing the leading edge so they could fit into the duct. This did look promising to proceed with a full model. One prototype was built with foam to begin the testing.
Exploring DEPRON
The goal to build lighter and stronger with foam seemed the logical choice. I began to search the web on foam, not yet familiar with the product DEPRON, my search was fruitless, but stumbling on sites focusing in foam plane construction I quickly discover this was new. My first discovery, a site FoamFly.com where the main product using Fan-fold. Fan-fold is a lightweight sheets of Extruded Polystyrene foam used for insulation under side paneling not available in Canada. This added to my frustration in obtaining this material. Now the trick is to find a supplier of this foam. I came across a site Yann's Model Airplanes he site demonstrated how fun foam plane can really be, simple and fast to build, any shape is possible. Here is where I found the magic word DEPRON, it did not register yet. It is funny how thing turn out.
I went to Toronto's annual Hobby show in search for new toys and discoveries. There the focus on indoor flight stuck with me. It appears that everyone is taking up or buying into the new thing with foam planes. They are much more forgiving when hitting the ground, so, maybe I will find this marvelous material among the booths. Only one booth had this product, and it came in 3 mm and 6 mm. I made the mistake of not buying at the time or asking what the product was. A month and a half later I went to my favorite hobby store to purchase a heat gun. I asked if they had foam sheets. Well.... The reply was ... You must mean DEPRON So... that's what it's called. At $8.50 for 15"x 39" was not attractive for me. I went home and search the NET. Now armed with the KEY WORD I searched for DEPRON. A sigh of content was in my breath as I searched. I quickly found sources and dimensions favorable for my projects.
I found 1 mm DEPRON at FoamFly.com. It is like working with stiffer construction paper, I was able to shape it in the same fashion I would with construction paper.
With an ordinary ball point pen, lines are drawn to score the surface making this easier to bend. I used a layering process for the construction of the wings. The control where added in. I tried to conceal them as much as possible. At 20 oz, and a paint job to make it look nice it is ready to go.
New Strategy
A new body prototype IV was created with no cut outs other than the battery cradle. A plug is installed after the cradle is cut; new wings are attaches, a new configuration with solid core wing, in an attempt to correct the previous problems of diving when slowing down. This did not improve the flight path in the test flights, so I start again.
I start with a new 6”x10”x20” (HxWxL) Styrofoam block. The cut lines are drawn for removal of the material, leaving the basic body shape. The inlet /shroud are made with construction paper, several layers making the tube stronger than the DEPRON tube. A small weight penalty, but will provide the extra strength needed. The top needs trimming to be flush with shrouds. The duct-vanes are added. Some detail shaping is done with 80 grid sand paper, this can be messy. My wife did not like this part much. To lighten the body, cut-out where done by using a soup can and twisting it through. This produces rough cut-outs, did the trick well. Skipped a whole bunch here, the model is done…
Ready for testing….. I for got…… There is a new wing configuration with this model in the attempt to provide a more stable glide path. Last test the plane would dive when it slowed down.
On the field…. Ready, go...
