Radio Control Model Aircraft:  Free Plans and Free Software

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  DH84 and me
De Havilland DH-84 Dragon-2, RC electric scale 94.7" wingspan, 1/6 scale "RIAMA"

I am so sorry to report that RIAMA, owned by Desmond Porter in Caboolture 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."  As I understand it he flew into heavy cloud that topped out above 10,000 ft, and RIAMA could not climb over.  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.  Terry Hicks of Caloundra Australia told me the story of how RIAMA got its name: "Des Porter's Father had a business of carrying newspapers from Brisbane to areas north and west of here on contract many years ago. One morning the plane was so overloaded it failed to get airborn, so it clipped a fence and burnt out.  As he was still obligated to fill the contract of paper delivery he needed a plane and fast, so he approached a friend and the replacement plane was purchased. That friend was Adrian Mair. The plane was named  in honour of the fact he helped a mate in need,  A. Mair spelt backward  or as we know it RIAMA".     I love that story. 

Breaking News!  My model of RIAMA will have a new home in Caboolture Australia.  The plane comes in 3 sections, and the crate for the plane was about 2 feet x 4 feet x 6 feet, 150 lbs total.

Des Porter and Riama
                                                                          Des Porter and his 2nd love, RIAMA.

Crated and ready for its new home in Australia

new pilot
The Dragon gets a new pilot!

DH-84 Dragon-2 electric-powered radio control 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 Riama flying 
This is another better quality video
Short video clip of 1/6 scale RIAMA flyby

  Riama at field

DH84 skeletondetails
DH84 inside shot

Skeletal view of wing structure

Fuselage on table

APL here stands for "Aircrafts Party Limited", an Australian designation
DH-84 side

DH-84 at rest

DH-84 closeup
A 12" GI-Joe makes a perfect 1/6 scale pilot, especially if you need a little nose weight!

DH84 quartering view


Now with wheel pants!!

Only one other person (that I know of) has made this model from my plans; Dan Schmidt.  See his beautiful model below (also an Australian bird, "Taniwha")

Dans DH84
Click here to see a youtube of Dan's model flying

Specifications of DH-84 1/6 scale electric model:

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 more DH-84 construction details

Click here to download the Assembly, Balancing, and Handling instructions

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, but 3-point landings must be done slow. One must fly it right down to the ground.

Click here to download a zip file of the DH-84 plans in Autocad14 format

Click here to download a pdf file of the DH-84 plans pg 1
Click here to download a pdf file of the DH-84 plans pg 2
Click here to download a pdf file of the DH-84 plans pg 3
Click here to download a pdf file of the DH-84 plans pg 4
Click here to download a pdf file of the DH-84 plans pg 5
Click here to download a pdf file of the DH-84 plans pg 6

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.

GAL ST-25 Monospar "Universal"
This is a rare bird indeed from 1935.  Only one example exists today, and that one was a rebuild after a crash and no longer flies.   It was used mainly as  a flying ambulance to transport  prone patients to hospitals.  The Universal extension to the name ment it was twin tailed, as opposed to the single tail "Jubilee" model.  I am still developing the plans, but if you look closely at the photo and 3-view you will see the root chord thinning out with a seperate horizontal beam/strut protruding from the side to the engine nacelle.  Very unusual, but the wings folded outboard of the nacelles with an upper hinge connected to this spar.  It has excellent visibility for the pilot.

Monospar 25

There are still details left out of the plans, so it is a project for the experienced scratch builder.  The wing root still needs carry-thru reinforcements to stiffen up that load path, but the experienced hand will know what to do.  I've designed this to be very light weight, as the fuselage is like a big stick & tissue truss model structure.  There are already 2 people that I know of that are going to build this model, even though I haven't yet built one!  I would anticipate using the same motors/batteries/props as I did in the DH-84, and that the flying weight would be in the 15 lb range if you keep to the build-light mantra.

Click here to download a zip file of the Monospar 25 pdf drawings. Six 72" x 36" drawings define this bird

The zip file also includes the best photos I could find on the internet for the Monospar 25.  Also, Jens B. Kristensen went to the trouble of making an MS Flight Simulator X model of the Monospar which flies nicely (I recommend you get it if you like to fly MS FS-X at  I made some screen shots which are also included in the zip file.

S-40a Flying Boat
The S-40 was the first Pan Am Clipper ship, dubbed the "Flying Forest" by Lindbergh.  We tend to forget, but flying boats were the pinnacle of aviation technology in their day when passenger service was reaching across the oceans.  Airframe construction advances, powerplant, navigation, radio, all were being pushed to meet the civil, then military demands.  This aircraft is an interesting mixture of the "new" and the old.  Starting in 1931, 3 were built that also had heavy landing gear.  This one I am designing is the S-40a from 1935 which removed the landing gear and had more powerful engines.  The outer wing panels will be removable at the dihedral break.

S-40 clipper

DH-90 Dragonfly
This next project was in the works, a de Havilland DH-90 Dragonfly, 1/5 scale with a 103" wingspan and twin 0.70 4-cyc engines.  The real aircraft 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.

DH-90 3-view

photo of full-scale DH-90
This is an ACTUAL aircraft, not the model!!

Click here to download the incomplete plans as they stand now

Traplet plans has an 86" wingspan 1/6 scale version for those who have grown tired waiting for me to finish the 1/5 scale (I might never...).  Just go to and search DH.90 DRAGONFLY.
Click here to link you to a youtube of the Traplet design model

Modified Stolp Starlet

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...  I never built this model but I believe it has been built

 Stolp Starlet 3-view

Click here to download plans in pdf format for the Modified Stolp Starlet model

Eagle Eye twin electric glider photographic platform

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.  I have as yet to produce viable plans... for the future!


Wilga 80, 55" electric model

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 55"

Click here to download plans for the Wilga in Autocad dwg format

1936 Monocoupe 110 Special

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!!

mono1 mono3
mono4 mono5
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 twice as much up aileron as there is down.

I used to have many more design programs available for download, but unfortunately this is a very dangerous world now.  Innocent aircraft design programs that were for the experimental aircraft hobbist can be misused by nefarious misguided individuals, organizations, and countries (you know who you are).  Too bad because I can't share it with the EAA or other hobby organizations.

Next is a simple to use V-n diagram application. V-n is of course velocity vs. g-load, the structural constraints of flight (without the additional factors of safety). It makes doing preliminary aircraft trade studies easier. Download the zip file and unzip it. Then double click the Setup.exe file and follow the instructions. Try it, you'll like it! All created in VisualBasic5. Version 1.5 March 2012
Click here to download setup program for the V-n diagram software

Next my latest is a helicopter performance program in vertical flight mainly to be used by radio control helicopter pilots. The head speed, pitch angles, and resultant performance can be shown in graph form. This should help with the programming of computerized radio controls (throttle and pitch curves) so that settings can be measured and tested "in the lab" to have the desired flight performance. Version 1.10 Aug 15, 2011. Note: since I am a new RC helicopter pilot, the example files that go with the software are rather thin. This is where you the experienced pilot can save files of your own successful settings (throttle and pitch curves, pitch ranges), and use them to figure your next helicopter of a different size. Also I would appreciate it if you could email me some interesting examples so I could fill out the sample files.
Click here to download RCHelicopterPerformance zip file

Next is an aid to gyrocopter (autogiro) design.  Equations and graphs from very old NACA reports have been internalized in this software, so, it is what it is (still better than nothing).
Click here to download the setup program for Gyrocopter Design

Interesting Links

FreeCAD, a 3D computer aided design tool
XFLR5: an analysis tool for airfoils, wings in model scale
UIUC airfoil data site
Airfoils for gliders
3-view plan drawings


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