Embedded Files
Spratt Controlwing
There are a number of good resources for information about the subject of the Spratt Controlwing. This page will present a number of such sources as an introduction to this important subject.
We have also recently added some video movies of Spratt Controlwing aircraft, including a flying boat built by Bill Wolfe. Click here to access those videos.
Bill Wolfe (billwolfe1@SBCglobal.net) has prepared an extensive collection of materials on the subject of the Spratt Controlwing.
Comments from Bill Wolfe on the Spratt Controlwing:
I first saw a demonstration and then flew a Spratt Controlwing flying boat prototype in 1969, immediately deciding it was the only type aircraft I would ever care to own.
Starting in 1895 Dr. George A. Spratt and later with his son George G. Spratt, experimented with and built a large number of successful gliders, flying boats, land planes and even a flying automobile as a joint venture with Bill Stout. All were aimed toward stable aircraft and safer aircraft control systems, and all of them used control wings in some fashion. (The Climax, Sport Aviation and CC Historical Society articles summarize these many projects.)
The Controlwing flying boat consists of a boat-like hull incorporating a fixed vee shape tail with a pusher prop nested close to the tail surfaces to act as a venturi to provide lift when under high power settIngs. The two separately hinged parasol wing panels are collectively, aerodynamically and automatically moved to maintain a relatively constant angle of attack in flight. This may be overruled by use of the auxiliary pitch stick to temporarily move above or below a stable flight path or nose high glide, to shorten a takeoff run or to flare for a smoother landing, both of which can be safely accomplished hands-off by power application alone.
The steering wheel moves the wing panels differentially to provide a gentle bank resulting in smooth turns and also steers a water rudder to enable fast turns on the water due to the wide hull, low CG and lack of outboard floats to trip over. There is no coordination required with this simplistic control system. The Controlwing is the safest aircraft In the world - a very docile aircraft, Inherently stable and with no stall, spin or dive capability. Only 1/4 of the normal G load is felt In turbulence as the hinged wing will automatically spill gusts if the stick is unrestrained.
For your reference, this is a listing of all the Spratt and Controlwing related flying boat articles which I have collected. Some of them (*) are included with the plans package.
Sept 1983-Sport Aviation-Reprint of George's 200#, 1936 Evinrude powered, roadable ultralight, lead aircraft in EM's "Old Time Aircraft" video. Taxi in traffic, rotate wing, then takes off. 1 pg
June 1945 - Popular Mechanics- The Spratt-Stout flying automobile. 2 pgs
Jan 1962 - Climax Magazine The Brain Behind the Wrights - The Dr. George A. Spratt story. 9 pgs.
June 1962 - Popular Mechanics - Controlwing flying boat cover article. 6 pgs
July 1969 - Philadelphia Evening Bulletin - No tail, no rudder, no ailerons, but it flys 1 pg
Sept 1969 - The AOPA Pilot - Movable Wing Controls Flying Boat. 2 pg
April 1970 - Science and Mechanics Magazine - Controlwing flying boat cover article. 4 pgs
July 1972 - Sport Aviation - My first Controlwing Experience. * 2 pgs
Dec 1973 - Sport Aviation - Prototype Land plane version of Controlwing by Jack Cox. 1 pg
June/July 1974 - Sport Aviation - Spratt history behind Controlwings. 12 pgs
1975 +/- Jane's All the World's Aircraft - Info only, no copies available.
May 1976 - Sport Aviation - First plans-built Controlwing flying boat by Joe March. 3 pgs
Mar 29-Apr 1, '77- Spratt's presentation to Society of Automotive Engrs., Wichita, KS. * 6 pgs
Mar 1978 - George's instructions to modify the 85 HP Mercury outboard for Controlwing use. * 5 pgs
May 1980 - Ultralights & Single Surface Wings by George Spratt. 5 pgs
Dec '94/Jan '95 - Smithsonian Air & Space Magazine - Freewing Co. and Spratt's ultralight. 1 pg
Oct 1998 - Sport Aviation - My Controlwing flying boat's first magazine appearance. 1 pg
1999 - EAA Experimenter - Shown In Technical Counselor section.
Apr 2000 - EAA Experimenter - Controlwing article by Harry Whiting 3 pgs
Chester County PA Historical Society -A massive collection of newspaper articles covering the lifetime aeronautical engineering accomplishments of Dr. George A. Spratt, especially his very generally unknown importance in developing Wright brother's first gliders and airplane 24 pgs
I offer copies of Spratt's 1973 flying boat plans with my changes marked, possible future design ideas, much general and technical material plus a 35 minute video showing operations of Spratt's prototype Controlwing flying boat and the Spratt prototype Land plane, some bystander's shots of my taxi testing runs and liftoff of my last flight before my medical expired. The package total cost is $115.00(U.S.)
(For further details, contact Mr. Wolfe at billwolfe1@sbcglobal.net)
Three extensive articles on the Spratt Controlwing published and copyrighted in June, 1974, July, 1974 and May, 1980 by EAA Sport Aviation are reprinted on the following webpages with their kind permission:
The ControlWing Aircraft (Part 1) by George G. Spratt
(here for PDFdownload)
The ControlWing Aircraft (Part 2) by George G. Spratt
(here for PDFdownload)
Ultralights and Single Surface Wings by George G. Spratt
(here for PDFdownload)
For a French view in English of the Spratt ControlWing, visit:
Le spratt ? un nouveau concept d'aéronef ultraléger !!!!
(cliquez image)
This aircraft was featured in the January 2003 issue of Experimenter-SportPilot and Light Sport Aircraft:
(We have been advised by the head of the firm producing these aircraft that the planned selling price is less than $4,500 and that this price includes the engine - contrary to the report in the above item.)
A rare photo of a Spratt Sky-Car from the extraordinary collection of aviation materials at www.Aerofiles.com :
"103 (Stinson)1944 = 2pChwM roadable; 90hp Franklin 4ACG pusher, replaced by 125hp Lycoming O-290C; span: 36'0" length: 21'7" v: 114/103/49 range: c.300 ceiling: 13,400'. George Spratt as Stout Sky Car IV (aka Spratt-Stout Model 8 Sky Car). Controllable-wing experiment with a stubby, podlike fuselage on four wheels, and a pivoting parasol wing to vary the angle of attack. POP: 1 [NX22448]. Reportedly was refitted with a 180hp Lycoming O-435 in 1945. Possible, but unverified, design connection with Cornelius Fre-Wing, aka Free-Wing." - from the Aerofiles website
For more information please visit the source:http://www.aerofiles.com/_convair.html
First flight of the above aircraft, also known as the Convair roadable controlwing, above Elizabeth City, N.C. in 1945
A much earlier Spratt flying automobile was preserved on film by the EAA in its fascinating Aerial Oddities VCR tape. An exerpt from that tape is reproduced (with their kind permission) in the Movies page. Click here to access that video.
To obtain a copy of the full VCR tape, described on the EAA website as
Aeronautical Oddities
From flapping wings to rocket-powered bicycles, these are man's early and sometimes humorous attempts at flight. As featured in the EAA AirVenture Museum. (17 min)
F35779 $9.99*
visit their website's online shopping pages:http://shop.eaa.org/html/2videos_history.html?cart_id=
George G. Spratt's patent on a controlwing aircraft issued December 10, 1968
Notes on Spratt Controlwings
1. Spratt, Schmittle, and Freewing
... in an airplane with conventional flaps. Free-wing
buffs, however, have come up with ingenious ways of
compensating for this deficiency. Spratts controlwing
http://www.airandspacemagazine.com/AS...
2. American airplanes: Sk - Sp
... The first controlwing airplane to do any real
flying. [14763]. Controlwing 1939 = 2pOhwMFb; 65hp
Lycoming pusher. Further development of Spratts
controllable ...
http://www.aerofiles.com/_sk.html
3. American airplanes: Fa - Fu
... 1930: Fowler Airplane Wings Inc. ... Based on
pivoting-wing principles originated by George A Spratt
(SEE Spratt Controlwing) and perpetuated by son George
http://www.aerofiles.com/_f.html
4. Technology: Tilt-Body
The Tilt-Body is a new kind of airplane, distinct ...
been known at least since 1949, when George G. Spratt
flew the first aircraft he called a Controlwing ...
http://www.freewing.com/tiltwork.html
5. EAA Sport Aviation INDEX - 1970s
... of Completed Amateur-Built or Restored
Aircraft.....23 The Light Airplane ... Challenge (Part
One)...by Franklin T. Kurt.....27 The Spratt
Controlwing ...
http://www.cozybuilders.org/ref_info/...
6. D THE MORNING NEWS
... years ago and got to fly the Controlwing Spratt
... Undaunted, Wolfe hauled the Controlwing home with
assistance ... Wolfe tinkered with his airplane/boat
trying to ...
http://www.nwaonline.net/pdfarchive/2...
(this link is down)
A modern variation on the Controlwing concept is under active development and marketing by Freewing Aerial Robotics Corporation, located in College Park, Maryland. The company is currently building only unmanned aerial vehicles (UAV) but produced several manned Freewing aircraft to test design elements.
Visit their website to see more information, including several excellent technical papers on the concepts:
http://www.freewing.com/freebird.html
A video of the Freewing MK-5 manned aircraft is included in the movies page. Click here to access that video.
Page updated
Report abuse