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De Havilland DH-84 Dragon-2, RC electric scale 94.7" wingspan, 1/6 scale

I am so sorry to report that the plane that this was based off, owned by Desmond Porter in Australia, crashed on Oct 1st, 2012. This clip from Australian news: "The deceased have been identified as the pilot and his wife - Desmond and Cath Porter - and two couples. Mr Porter, who had been raising funds for charity at an airshow before the crash, survived a crash in a plane of the same model in 1954 that killed his father and brother. He rebuilt the current plane 50 years later using parts from one that crashed at Archerfield aerodrome 6 months prior to his father's crash." There are only 3 Dragons left flying in the world now. This is a terrible loss for the 6 people who died and the beautiful vintage biplane that will now only fly as a model.

On this page you can download the design & construction article and the plans for this unique radio control flying model, the DH-84 Dragon. I fly it at the club field in Laurel Maryland (FreeState Aeromodelers). The outer wing panels (28" each) come off without any fuss by removing 4 connection pins per side. There is no hard attachment for the aileron controls (done with a push-push system of pin-in-socket), and the wing wires are permanent and do not need adjustment or re-attachment. This makes for a very easy set-up and take-down, only a few minutes total. The wing wires are functional and very much part of the structure, just like the real aircraft. Indeed, much of the model structure is very similar to the actual aircraft in both configuration and function.

See a Youtube video of the Dragon flying

This is another flight on Youtube (better quality)

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dh84skeleton.jpg

DH84-b.jpg

APL here stands for "Aircrafts Party Limited", an Australian designation

DH-84side.jpg

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A 12" GI-Joe makes a perfect 1/6 scale pilot, especially if you need a little nose weight!

Specifications


Wingspan = 94.66 inches, airfoil = 10.3% flat-bottomed with slight re-flexed trailing edge


Length = 68.6 inches


Wing area = 1700 square inches


Weight = 14.5 lbs take-off weight, 12.5 lbs without motor or batteries


Wing loading = 19.6 oz/ square foot


Static thrust ~ 10 lbs; Static thrust / weight ratio ~ 0.7



Power System

Motors = Two AXI 2826-10 brushless out-runners, 35-40 amps current each

Props = APC 11x5.5 props

Batteries = Two Poly-Quest TW 4350XP-45 Li-Po batteries (14.8 volt 4350 milli-amp-hour)


Controllers: = Two Jeti Advance 77 Opto plus controllers. These were oversized to guarantee that there will never be a single-engine situation at takeoff due to one controller slightly going over the current limit.

CLICK HERE TO DOWNLOAD THE DH-84 CONSTRUCTION PDF DOCUMENT

CLICK here to download 2nd construction document with many detaied photos

The drawings for the DH-84 rc model are in a .dwg vector format. Programs such as Autocad or Intellicad can be used to open it. The drawings are not complete in every detail, and this project is best tackled by an expert scratch builder. Also, the prototype model has no shock absorption, and from the experience of flying this model, it would do to incorporate Robart shock struts into the main landing gear. This aircraft loves wheel landings and hates 3-point landings. One must fly it right down to the ground.

Click here to down load a zip file of the DH84 Dragon plans in dwg Autocad14 format

Click here for a free dwg format viewer

click here to download a pdf file of page 1 of the DH84 plans

click here to download a pdf file of page 2 of the DH84 plans

click here to download a pdf file of page 3 of the DH84 plans

click here to download a pdf file of page 4 of the DH84 plans

click here to download a pdf file of page 5 of the DH84 plans

click here to download a pdf file of page 6 of the DH84 plans

These plans have also been uploaded to the free plan site http://plans.aerofred.com/. Just search for DH-84b

Kinko's and other print shops can print these plans. They will use their "large format" printer. Each drawing is approximately 72" x 34". You can also email the pdf files directly to Kinko's, or you can write them to a CD and physically give it to them.






Next is a project in the works, a de Havilland DH-90 Dragonfly, 1/5 scale with a 103" wingspan and twin 0.70 4-cyc engines

I do not believe this plane has ever been modeled in RC, the real one is a challenge to land (the tail would be shadowed by the fuselage during a 3-point landing and ground loop), and there were tip stall problems. It is however a very beautiful looking aircraft, but demands respect.

DH90-b.jpg

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This is an ACTUAL aircraft, not the model!! Hopefully when the model is completed, it will be hard to distinguish model from real.

click here to download DH90 plans as they now stand (a little incomplete)


Another set of plans in the works is from a home built aircraft of the 1960's, a modified Stolp Starlet parasol. I would say the strictly scale plans have a too-small horizontal tail to give steady pitch control. You may want to scale it up just a tad...

Starlet_3-view.jpg

click here to download the zip file containing pdf format plans


The next project is an aerial photographic platform for small point-and-shoot cameras. I want it to be hand launchable and have an unobstructed view that can be tilted from straight down to full forward(thus twin motors). I call it the Eagle-Eye1, with 120" wingspan and 1100 sq inch of area.

EagleEye1.jpg









This is my Wilga 80, 55" wingspan which is electric. It has a 39.3" length, 400 sq inch area, and weighs 39 oz full up with an 11V LiPo 2100 mAhr. The motor in the prototype was a Mega 16-15-4 with a 3.6:1 reduction, swinging a 12x6E APC prop. Turns are definitely coordinated with rudder!

Wilga-a.jpg

click here to download the Wilga plans in Autocad dwg format






Another set of plans in the works, this is a Bucker 181 Bestmann, scaled to 104" wingspan (1/4 scale). This is another aircraft that I believe has rarely been modeled in RC.

Bu181-a.jpg






Next project is one I recently finished, a 1936 Monocoupe 110 Special, "Spirit of Dynamite", 1/4 scale. It stands at 69" of stubby wing span, 10 lbs flying weight,and ~ 915 sq inches of wing area (25 oz/ft^2). Scratch built from Jack Swift plans, slightly modified (of course). I use a Saito 125 4-cycle which gives it all the power it needs.

This is a fantastic flying model!! Very scale-like in flight, handling and landing. A little quirky in the handling, but it is a gem of a design!!

Monocoupe1.jpg

Monocoupe3.jpg

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AileronDifferentialServo.jpg

This is the way I accomplished aileron differential without separate servos or biased bell cranks in the wings. I put the bias in the servo arm itself, with servo pushrod connectors on both sides of the servo arm as shown, going to flex-wire pushrods. The spacers allow motion without running into the center arm connection. There is about 2x as much up aileron as there is down.







The following are interesting links for R/C aircraft

Free Autocad dwg drawing viewer by Informative Graphics

FreeCAD, a free 3D CAD program that can read and draw igs and step files. Will not read 2D cad files like dwg or dxf.

Balsa USA, a great source for scratch building supplies and kit models

Link for Free State Aeromodelers in Laurel MD

Ted Allison's Dragon Rapide

Aircraft Plan 3-views

Nick Ziroli Plans

ICARE gliders

Sky Bench Aerotech

Northeast Sailplanes

Soaring USA

Espirit Models

Airfoils for gliders

UIUC Airfoil data site

XFLYR5 Airfoil and Wing Analysis Tool