---
created_at: '2016-04-16T16:51:03.000Z'
title: Facetmobile FMX-4 Research Airplane (2008)
url: http://www.wainfan.com/facet.htm
author: akavel
points: 62
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created_at_i: 1460825463
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- story
- author_akavel
- story_11511259
objectID: '11511259'

---
[Source](http://www.wainfan.com/facet.htm "Permalink to Facetmobile Home Page")

# Facetmobile Home Page

![Facetmobile Home Page][1]

#### **The Facetmobile is a Low Aspect Ratio Lifting Body Experimental Homebuilt Airplane. It is stall-resistant, easy to construct, and voluminous.**

_**_Page  Updated 11/9/2008_**_

* * *

**_Facetmobile Video_**

[**Go to Facetmobile FAQ page**][2]

 

* * *

[ ![][3] ][4]

[NASA PAV (Personal Air Vehicle) Facetmobile Project ][4]

* * *

## **_FACETMOBILE FMX-4 RESEARCH AIRPLANE_**

  ![][5]      ![][6]  
  
![][7]    

The Facetmobile is an experimental lifting-body sport airplane. It was built by Barnaby Wainfan, Rick Dean, and Lynne Wainfan to explore the characteristics and potential of this type of airplane.   
 The configuration was developed using a combination of analytical methods, radio-controlled model testing and wind-tunnel testing. In all, 8 radio-controlled models were built and flown. Construction of N117WD took 2 1/2 years. First flight was April 22, 1993. Total flight time to date is approximately 130 hours. No plans or kits are currently being offered.  

![][8]

In 1994, the airplane was flown to Oshkosh, WI from Chino, California and back. On the outbound flight it covered 2,253 miles in a total air time of 25 hours and 46 minutes. 

On Oct. 13, 1995, while enroute to the Copperstate Fly-in, the Facetmobile experienced an in-flight loss of power due to a carburetor malfunction, and Barnaby was forced to make a dead-stick landing. He was unable to avoid a barbed-wire fence, and hit it at approximately 30 knots. The airplane was damaged, but Barnaby was not. N117WD is currently being repaired, and will fly again .

![][9]

**Physical Characteristics:**  
(As originally flown with a Rotax 503 engine)  
Length: 19 ft. 6 in.   
Span: 15 ft.  
Empty Weight: 370 lb.  
Fuel (normal): 10 gal.  
Fuel (with aux): 19 gal.  
Gross Wt.(normal): 620 lb.  
Gross Wt. (max): 740 lb.  
Structure:6061-T6 Aluminum tube  
Covering: 1.6 oz Stits fabric  
Engine Rotax 503DC

**Performance:**  
Maximum Speed: 110 mph.  
Cruise Speed: 90 mph.  
Stall: No stall: stable mush.  
Min. Speed: Less than 30 mph.  
Rate of Climb: 750 ft/min.  
Range (10 gal) 150 miles  
Range (19 gal) 300 miles  
Ceiling(620 lb.) 11,000 ft.  
Minimum Runway: 1000 ft.

**Flight Characteristics and Capabilities:**  
Highly Maneuverable: Roll Rate of 180 deg/second.  
Highly Departure Resistant.  
Forgiving Flying Qualities.  
Maintains Level Flight at Angles of Attack Over 30 Degrees.

 

_**Flight Test Results**_

The FMX-4 flight test program conclusively demonstrated that the low-aspect-ratio, faceted, tailless configuration is viable for a light general aviation airplane. The overall performance of the airplane compared well with the performance of conventionally-configured airplanes using the same power plant.  The airplane demonstrated the ability to carry a useful load equal to its empty weight. 

The flying qualities of the FMX-4 are benign and conventional.  Control forces are linear, and well harmonized. The airplanes motions are well damped about all axes. Very little rudder is required to coordinate turns in up-and-away flight. 

In the approach configuration, the airplane has a strongly stable dihedral effect. Dutch roll is well damped, so the primary effect of the strong lateral stability is the need for significant lateral stick force to maintain a steady-state sideslip during a crosswind approach. 

The airplane is highly departure resistant at high angles of attack.  The airplane did not have angle of attack instrumentation, but wind tunnel results indicate that full aft stick should trim the airplane to approximately 30 degrees angle of attack. In flight test, in the full-aft-stick condition, the airplane exhibited a moderate high-frequency aerodynamic buffet, and a power-off sink rate of about 1000 feet per minute. Roll damping remained stable, and the airplane exhibited no tendency to roll off or depart, even during gentle lateral maneuvering. The controls remained effective about all axes. 

The aircraft was not equipped with a flying pitot head. Accordingly, the true minimum aispeed could not be measured because the fixed pitot tube stalled at high AOA, leading to an airspeed reading of zero on the airspeed indicator before buffet onset. Wind tunnel data predicts that the steady-state airspeed at the angle of attack for maximum lift is approximately 33 knots. 

These flight test results, as well as results of more aggressive high angle of attack investigations conducted with the scale radio-controlled model indicate that the FMX-4 is highly spin resistant and will not be prone to the typical stall/spin accident seen with conventional airplanes. 

The FMX-4 test program demonstrated that the configuration offers many advantages as a personal air vehicle. The primary advantages demonstrated are: 

> > * **Simple primary structure, with low parts count**
>> * **Airframe structure composed of low-cost materials**
>> * **High useful load fraction**
>> * **Benign flying qualities**
>> * **Stall and Spin resistance**
>> * **Large tolerance of center of gravity travel**
>> * **Superior occupant protection**
>> * **Roomy cabin**
>> * **Performance comparable with conventional airplanes.**
* * *

 

> > [ ![][10] ][11]
>> 
>> [Popular Science Reports on the Facetmobile Project ][11]

* * *

**_Published Articles and Pictures of the Facetmobile_**

  
Photographs and/or articles describing the Facetmobile have appeared in the following publications:  
KITPLANES: 9/93  
KITPLANES: 2/95  
KITPLANES: 3/95  
Sport Aviation: 10/94  
Experimenter: 10/94  
Air Progress: 1/95  
Air Progress: 2/95  
Flying: 10/94  
Pacific Flyer: 2/94  
Model Builder: 10/96  
Flight (Air Age): Nov/Dec 1996  
Volare Sport (Italy): 10/94  
Aero Revue (Switzerland): 6/95  
Aircraft Illustrated (UK) 5/95  
Contact Issue 71  
[Popular Science: January 2005][12] (**NEW 1/7/2005**)   

* * *

** You can download free plans for a Facetmobile paper card model from Ralph Currells site:**

_  [Free Paper Card Model Plans by Ralph Currell][13]_  

* * *

## _**FACETMOBILE FMX-5 PROJECT**_

The FMX-5 is our vision of a personal airplane using the concepts pioneered by the Facetmobile.  The project is currently dormant, since we do not have the resources to complete the restoration of the Facetmobile N117WD and build a new prototype at the same time. We are continuing to do extensive engineering work to refine the design.  The FMX-5 project remains a concept. We are still working on the design, refining it, and optimizing it to fit into the new Light Sport aircraft category. FMX-5 is evolving into SPORT FACET.  

Once the restoration of FMX-4 is complete, SPORT FACET  will be our next priority project.  We are interested to hear from individuals or organizations with the resources to help make this exciting new airplane a reality

**A MULTI-FACETED OPPORTUNITY!**  
We are interested in talking to individuals or groups who want to help make the FMX-5 SPORT FACET a reality faster than we can do it ourselves. Up to now the project has proceeded as a homebuilt project. It is happening only as fast our available time and money will allow. Although we will continue this effort, we are receptive to other approaches to moving the FMX-5 ahead. A focused, well financed effort can have a prototype flying much sooner, and lead to early kit production.   
If you have the resources to help make FMX-5 a reality, and want to be a part of a whole new facet of aviation please contact us.  
You can reach us by e-mail at: [Facetmobile@Yahoo.com][14]

 

**_FMX-5 DESCRIPTION_ **

  
 ![][15]  
**FMX-5 15% Radio-Controlled model and Wind Tunnel Model Installed in the Cal Poly Pomona Wind Tunnel**

  
The FMX-5 is a new aircraft design based on the Facetmobile FMX-4 (N117WD). The FMX-5 design is a 2-seater projected to use engines in the 100 to 150 horsepower class. It is not simply a scaled-up Facetmobile, but incorporates many improvements based on what we have learned in 130 hours of flying N117WD. The prototype will be powered by either a Lycoming O-235 or the new Jabiru 6-cylinder engine, and the structure will be stressed to handle engines up to 150 hp, including the Lycoming 0-320. The baseline structure of the FMX-5 is similar to the FMX-4: a mix of steel tube, aluminum tube, and sheet aluminum covered with fabric.  

We are also investigating an alternative version composed of flat composite sandwich panels. The composite flat-panel design is suitable for highly automated manufacturing using numerically controlled cutters (water jet or laser) to cut out the panels. The panels are designed to interlock so that the structure will be self-aligning and require a minimum of jigging for assembly.  

We want to offer FMX-5 as a kit once the prototype has satisfactorily complete flight testing. 

A major advantage of the low aspect ratio lifting body configuration is the large useful volume inside the airplane. In conventional airplanes, the cabin is kept as small as possible to minimize drag. This restriction does not apply to the FMX-5, which carries two people in a cockpit which measures 80 inches between the window sills. Each seat is 20 inches wide, and they are separated by a center console, which houses the stick, and acts as a fore-and aft systems tunnel for control linkages. There are windows in the floor on each side of the cockpit. There is a large baggage compartment behind the seats. A child seat can be installed in the baggage compartment. 

A 15% scale radio-controlled model of the FMX-5 has been built and extensively flown. It flies well, and has flying qualities very similar to the models we flew during the development of the single- seat Facetmobile. In particular, FMX-5 retains the excellent high angle-of-attack controllability and departure resistance shown by the Facetmobile (N117WD), both in model form and full scale. The model could be routinely flown with full-aft stick, and remained controllable, with no sign of a stall or spin tendency. A 1/16 scale model of the FMX-5 was tested in the Cal Poly Pomona wind tunnel. The data taken confirm the configurations docile aerodynamics, and also show a 40% improvement in L/D over the original Facetmobile configuration.
* * *

 

**_FMX-5 Ultra High Altitude UAV: _**

![][16]

**While progress on the restoration of the original Facetmobile, N117WD, has been extremely slow, other exciting things have been happening in the Facetmobile World. For the past few years, an unmanned FMX-5 has been under development to return payloads from balloons flying at extremely high (over 98,000 feet) altitudes. These FMX-5 based vehicles have been flying since mid 2005. We have just now been given permission by our customer to reveal a little about this program. Click on the picture to learn more about it.**

* * *

**![][3]**

## **_NASA PAV (Personal Air Vehicle) Project_**

![][17]

  [**Click here to read the study final report (1.4 MB)**][18]

In 2003, in partnership with the California Space Grant Foundation we won a NASA contract to study the application of Facetmobile low aspect ratio airplane concepts to the design of future Personal Air Vehicles.  The study examined  building a low aspect ratio airplane like the one pictured above using pre-cured composite sandwich panels cut on numerically controlled machinery to form the major components of the airframe.

![][19]

**Conclusions From The NASA PAV Study:** 

* Flight tests of the FMX-4 have shown that a faceted low aspect ratio all-lifting airplane can have good flying qualities, compatible with a modest level of pilot skill and be highly departure resistant. 
* A faceted low aspect ratio all-lifting airplane can have performance comparable or superior to a conventional airplane having the same power carrying the same useful load. 
* Due to its intrinsic structural efficiency, a low aspect ratio all-lifting airplane will have an empty weight that is approximately 55% of that of a conventional airplane having the same useful load and cruise performance. 
* The low aspect ratio study airplane, with 80 horsepower has up-and-away performance comparable to the current-generation all-metal trainers powered by the 115 horsepower Lycoming O-235.  It is significantly superior to the conventional all-metal airplanes in terms of takeoff distance and rate of climb. 
* The overall system-level transport efficiency of the low aspect ratio study airplane is significantly superior to the classical riveted all-metal airplanes, and comparable to a modern, molded all-composite machine. 
* The low aspect ratio all-lifting configuration composed of flat panels is well suited to automated manufacture of components, and will require many fewer hours to assemble than a conventional configuration. 
* The flat-panel construction of the study configuration allows it to take advantage of cost savings available from use of CNC high-speed machinery without the need for the airframe manufacturer to purchase or maintain expensive machinery or tooling. Large cost savings can be realized even at low production rates. 
* The non-recurring cost of tooling and specialized machinery required to fabricate the parts for a faceted low aspect ratio all-lifting airplane and assemble the airframe will be much lower than comparable costs for a conventional wing-body-tail configuration. 
* Due to its combination of light weight, compatibility with automated manufacture, and reduction in assembly labor hours, a low aspect ratio all-lifting sport/trainer airplane similar to the study configuration can cost up to 50% less than a conventional airplane designed for the same mission.
* * *

![Facet cartoon][20]

* * *

You can reach us by e-mail at: [Facetmobile@Yahoo.Com][14]

Or you can read more about us at [Wainfan Home Page][21]

* * *

This page was created by Lynne Wainfan   
All Rights Reserved. All images on this page are   
Copyright Barnaby & Lynne Wainfan. No commercial use   
is authorized. Cartoon courtesy KITPLANES Magazine. In-flight FMX-4 image is copyright EAA, used by   
permission of EAA. Facetmobile image in logo and background courtesy of Koen Van de Kerckhove.   
[ ![Site Meter][22]][23]

[1]: http://www.wainfan.com/fphead2.jpg
[2]: http://www.wainfan.com/fmfaq.htm
[3]: http://www.wainfan.com/nasalogo.jpg
[4]: http://www.wainfan.com/facet.htm#FMNASA
[5]: http://www.wainfan.com/FMX4IF1.JPG
[6]: http://www.wainfan.com/FMX4G6.JPG
[7]: http://www.wainfan.com/1stflt.jpg
[8]: http://www.wainfan.com/fmoshkosh.jpg
[9]: http://www.wainfan.com/3VIEW.JPG
[10]: http://www.wainfan.com/popscicover.jpg
[11]: http://www.popsci.com/popsci/aviationspace/fbc889c49db84010vgnvcm1000004eecbccdrcrd.html
[12]: http://www.popsci.com/popsci/aviation/article/0,20967,1006802,00.html
[13]: http://www.currell.net/models/mod_free.htm
[14]: mailto:facetmobile%40yahoo.com
[15]: http://www.wainfan.com/fmx5.jpg
[16]: http://www.wainfan.com/prvsmall.jpg
[17]: http://www.wainfan.com/nasafm.jpg
[18]: http://www.wainfan.com/pavreport.pdf
[19]: http://www.wainfan.com/internal.jpg
[20]: http://www.wainfan.com/fmtoon.jpg
[21]: http://www.wainfan.com
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