Saturday, August 25, 2007

Business Models

Commercial aircraft, like any other sort of industrial equipment, should not be designed in a vacuum. Designers need to understand the business environment as well. This includes both how the aircraft is to be financed and insured as well as how the aircraft is to be used to make money. After all, unless this aircraft can support a profitable business, it's a failure.

The basic business model, call it Model 1:

Air-shuttle bus to the airport.

Model 2:


Model 3:

Air ambulance.

Model 4:

Air cargo.

Model 5:

Scheduled feeder routes.

Model 6:

Sky-diver aircraft. Should include smoke-jumpers, too, I suppose.

Model 7:

Deep rural combi. That is, both passengers and cargo on the same aircraft, on the same deck (legally).

Model 8:

Water-bomber. Especially appropriate for amphibian model. Non-amphibians might make a very nice foam bomber with a payload in excess of 4,000 lb.

Model 9:

Bush flying. Both land and amphibian models, with and without skis.

This is just off the top of my head. More detail to follow.

Wednesday, August 15, 2007


The initial configuration, the baseline if you will, is a high-wing, tricycle-gear, three-surface turboprop with the engines situated above the wing in the same manner as the YC-14 and the QSRA for upper surface blowing.

The trailing edge flaps are single slotted and plain with variable camber Krueger flaps on the leading edge. This is entirely notional at this point.

The main deck of the aircraft is the upper surface of the broad keel beam that forms the structural backbone. A "crown beam" extends from the wing center section forward to the cockpit (41 section) and aft to the pressure bulkhead at the end of the 46 section. The main and nose landing gear attach to the keel beam.

The keel-beam volume is to be “protected,” or blocked from penetration by other systems in order to be able to use that volume later in the program for extra fuel.

There is no cargo deck, no separate cargo compartment. Baggage is all carry-on to be stowed beneath the passenger's seat, in the overhead bin or in the closets. There are still unanswered questions about what to do for skis and golf clubs.

The seats face aft for better crashworthiness. Seats are designed to allow baggage tucked underneath

The body resembles the Piaggio P-180. The intent is to get some lift from the body, or at least a very nice nose-up pitching moment.

After exchanging emails with John Leslie of the UK, we are adding some cool features:

Multiple large and powerful landing lights with big off-axis taxi-lights as well.

In lieu of an FMC, add a GPS/IRS moving map like the Garmin’s G1000.

The cockpit windows are all interchangeable so that a crack in a windscreen won’t cause a grounded aircraft. Just shift that pane from the front to the side and re-dispatch.

Large, aerodynamically-balanced control surfaces for good low-speed control. No wing spoilers for roll control, just ailerons. No hydraulic boost, no fly-by-wire, just manual control.

The tires are big and soft to operate out of grass fields. The mains are duals using the same tire as on the nose. Gear is retractable.

A large main-deck cargo door forward of the wing on the freighter, combi, and air-ambulance variants. (A “combi” is a Boeing term for an aircraft that is designed to fly both passengers and cargo on the main deck at the same time.)

The aircraft is designed for pressurization, but the initial model likely to be designed and built without the air-conditioning pack for systems simplification and weight.

Single-pilot certification for cargo-only.

We are still discussing whether a lav should be on-board or not. The comfort argument is obvious, but the weight and complexity argue against it. Perhaps the best thing to do is to block out space, structural, and systems provisions for a lav, but not to design it in on the initial models. Anyone have any thoughts?

More later.


I'm not an avionics person, really. But I do know that the current crop of FMCs and autopilots for heavy jet transports are very complex. Not just technically complex, but operationally complex. So complex, in fact, that pilots are often left wondering, "Why is the airplane doing that?" I hate that.

Our avionics should be very easy to understand. Push the button on the glare shield and get best climb rate (or best climb angle). None of this C* climb function stuff. Oh, and the pilot should be able to turn it off with one switch and not have the airplane crash. The avionics are there to help the pilots, not to do their jobs for them. People make lousy systems monitors.

Moreover, I think this may well be a lovely opportunity to try open source avionics on an open standard network. I'm really in love with the idea of a simple (I know, I know) Intel box running Linux as an OS and an open source application (FM or AP) on top.

The best part? We're not alone. Thomas Netter pointed me towards these sites:

Who would like to get started on this one?

Design Requirements And Objectives

Lets start at the beginning, shall we? For airplanes, that's range and payload.

Minimum requirement out of the box is 500 nautical miles. Targeted objective is 1,000 nm. We need to be able to get to the larger airports from small rural fields; at this point I'm not interested in transcontinental performance (I've flown from Hawaii to California in a turboprop, seriously, get a ticket on a jet for the long haul).

The intent is to allow the operator to make two round trips before having to refuel, each round trip to be approximately 200 nautical miles in length on average.

Initial range and performance to be done with Jet A, or the current commercial equivalent. Once we have that, then we can do a trade study to switch to ethanol or bio-diesel. From what I've read in the trades, hydrogen is a long way down the line, but I can buy ethanol today.

Twenty paying passengers with two air-crew. I'm not familiar enough with part 135 operations to know if a cabin crewmember will be required.

Remember, this is an air-taxi and not a scheduled operation we are supporting. Therefore, twenty seats may well be at the large end. My thought is that at ten seats and below, we are competing with Cessna and over forty seats, I think we go head-to-head with Bombardier. I don't have any real data that supports my assertion that there is a hole in the market at twenty seats, but that's my feel. Clearly, we want to stay out of the hundred seat (give or take twenty seats) market.

Building a four to ten seat personal airplane is very do-able. Getting a twenty-seat airplane built for commercial use is a very different project, but still in the range of quite feasible. We aren't talking billions of dollars here. In fact, with good academic support we may well be able to build the prototype for very little indeed.

Cruise Speed:
250 kts.

Tentatively planned to be a Pratt and Whitney PT-6 of some form or other. The reason I am specifying a turboprop instead of a small turbofan is because of the short, soft field that I expect to be a significant part of air taxi operations all around the world. Turbofans have a bit of a lull in acceleration, which can be operationally significant. I'm willing to trade performance at altitude for better short runway performance. As for other engines, I'm perfectly open to whatever you guys have data for.

Hello World!

Welcome to the new home of a new kind of project, a global
mass-collaboration to design a new aircraft. Think of it as
a sort of Linux with wings. This is the original email I
sent out to as many people as I could think of to begin the
creative process.

If you got one of these, either directly from me, or
forwarded from someone else, consider yourself present at the
creation, hence the name of this blog. You are in really
excellent company.

Call for Comments

I've been reading Tapscott's and William's new book,
"Wikinomics." I recommend it.

I'm inspired by it to try a new mass-collaboration event.
I intend to start a project like Linux, but to design
(and eventually offer for manufacture) a twenty-seat
commercial aircraft to provide air-taxi service in rural
regions that can't support scheduled commercial operations.
The current configuration is a high-wing, tricycle gear,
three-surface, twin-engined turbo-prop with the engines
situated above the wing a la QSRA. The design intent is
safe, reliable operation out of soft, unimproved fields
and a high cruise speed for good economic productivity.

There are a LOT of things that will have to be resolved
before we can declare victory, but those things will be
very helpful to everyone, I think. We may need open source
versions of finite element analysis programs, vibration
analysis programs, CAD programs, aero-analysis programs,
and no doubt a bunch of other software that I'm not even
aware of at this point. Moreover, we will have to break
trail on new processes for aircraft certification. Make
no mistake, this is fraught with difficulties.

The cool part is that at completion, we will have a fully
designed and certified aircraft with no IP (intellectual
property) costs. The whole thing will be done under a
general public license. This can be a big help to drive
down the costs of this aircraft. With the cost of acquisition
lowered to something that one or two people could conceivably
get a loan to buy, we put the pilot community in the same
place truck drivers have been for decades: they can own the
means of production and become owner-operators. Moreover,
this can open up vastly improved air communications to people
who live in sparsely settled areas around the world.

With a general public license, the airplane can be
manufactured just about anywhere: China, India, the US, Europe.
Anywhere where a firm can be found or established to obtain a
production certificate.

One minor variation is the seaplane. For those who remember
the Grumman Widgeon that snap-rolled into the surf in Florida,
this is an opportunity to replace that generation of seaplanes
that should have been replaced decades ago with a new model
that will be much safer and more reliable, if one with
somewhat less cachet.

One further cool thing: I intend for it to be as
environmentally benign as possible through selection of
materials and design for sustainable bio-fuels (pretty
trivial technically, but important) like bio-diesel and

I think we can get people to work on this in their spare time,
especially college students. This is a great resume item,
rather like participating in a Linux development team. There
are also a lot of airplane professionals who aren't doing the
sort of work they'd like, or perhaps aren't doing any work at
all, and would like to indulge themselves by working on a
design team. It's cool.

To really put the cat amongst the pigeons, I’m thinking that
we may want to design and build an open-source FMC and
possibly even an open-source auto-pilot. Frankly, my
understanding of avionics is slightly more sophisticated
than rubbing sticks together, but even I am aware (through
the generous offices of the people on this list) that they
are mostly computers. With this in mind, would someone please
cross-post this to the Bluecoat (Bluejacket?) mailing list?
I used to be a member some years ago, but now I can’t even
remember who to email to be added again. My thanks in

My next steps are to find the right software to run this
kind of effort and to find someone who is willing to host
it. I have a few ideas, and I'm wondering if you folks
have any.

Best regards,

Terry Drinkard