I’m sure many of us remember James Bond flitting around in a tiny Bede BD-5J microjet, playing tag with a ground-to-air missile in the film ‘Octopussy‘.
With the failure of Bede Aircraft Corporation, it seemed for some time that the era of the microjet was over. However, Sonex had their own ideas about that. Courtesy of the latest entry in Earthbound Misfit’s ‘Sunday Jet Noise’ series, I learned of the latest iteration of Sonex’s SubSonex single-seat build-your-own jet aircraft. AVweb says of it:
The kit with engine costs about $130,000, so by the time you throw in the avionics, paint and other extras, call it $150,000 to $160,000. For a jet, even a single-seat jet, that’s not a lot of money in the context of upper strata experimentals or even LSAs. In fact, it strikes me as a decent value for a would-be builder or owner who passionately wants to fly a jet airplane.
. . .
How would you use such a thing? I think it’s primarily a VFR sport flyer similar to other experimentals or LSAs. Take off of a Saturday morning and burn up 30 gallons of Jet A beating up the local area and the pattern. Great fun. (You’ll need a longish runway, however. The SubSonex isn’t exactly a STOL airplane and the brakes need improving.)
Sonex gives the still air range as 480 miles at a 240-MPH cruise, so you could use the airplane for light travel, although it would take planning and effort. It burns about 34 GPH during takeoff and typically half that in cruise with a 40-gallon capacity. I wonder if a creative builder might find room for a little more fuel.
The engine is a 40-pound jewel of a creation from PBS Velká Bíteš, a Czech Republic company formerly in the Soviet orbit. The TJ-100’s origins are in APU applications, but it finds use in small UAVs today. Rated thrust is 250 pounds, which Carleton says is a perfect match for the airplane. When we were shooting the airplane, he explained how a jet engine’s simplicity percolates down through the airplane itself. With no heavy structure to support a piston engine and no linkages for throttles and props, the SubSonex is an exceptionally simple build. The engine is FADEC controlled and throttle by wire, so the only connections are the fuel line and a few wires. Carleton told me when he tours with his Salto glider for airshows—same engine—he unpins the engine and takes it into his hotel room at night. Try that with an IO-320.
There’s more at the link.
Here’s the SubSonex in action at EAA’s AirVenture show at Oshkosh, WI in 2014. Watch it in full-screen mode for best results.
Looks like a fun toy. I wonder if Miss D. would like to fling one of those around the Texas sky? Note to self: must sell more books . . .
I think that demilled cruise missiles and drones would make excellent small planes. Strip the insides of all that autonomous stuff and warheads and you are left with some decent room for a cockpit and pitlot (maybe a passenger).
Seems to be suffering from poor design and lack of thrust.
"Seems to be suffering from poor design and lack of thrust."
Actually not. The aircraft uses standard Sonex building methods and materials which are designed for the home builder. Given 250# of thrust, this is a pretty optimal design. Don't be surprised if Monnett (the designer) comes up with a twin engine version using more efficient engines.
Here's another way of looking at it. Let's say you build this over a 5 year period. I have friends that have taken ten years to build a kit propeller driven plane. Five years is $35,000/year. I don't know how much of the price is amenable to that line of thought, but bear with me a moment. How much income do you need to salt away $35k? Obviously you need a bit more than $35k income, but it really seems within the realm of any dedicated hobbyist. Engineers, doctors, techno-geeks of all kinds.
Re: "Seems to be suffering from poor design and lack of thrust." All small planes suffer from lack of power, in my mind. Look up specs on a two-seater and figure out how much stuff you'd like to take if you went on vacation in it.
I haven't look for a few years, but there was several companies that were supporting the BD-5, both prop and jet. Bede never even got customer aircraft into the air, as he never finished the drive line development before going bust. That was done by a company here in San Jose, in the late 70's. They had all the rivet drill forms for building the various sub-assemblies, that a home-builder could rent the use of at their shop.
They finished the design and fab of the driveline, and got quite a few in the air with turbocharged Honda Civic(?) engines.
One of their customers made an expensive mistake. Well, several, actually. He had a -J model, and since he wasn't planning on flying it for a bit, he did not have full insurance coverage on it. He was towing it home on the trailer designed for it, and forgot to latch the ball hitch. He also neglected to use a safety chain. On the freeway, a bump caused the hitch to uncouple, and the trailer went over an embankment and tumbled down the hill. They had it sitting in the shop, and there wasn't a single unwrinkled panel anywhere on the plane. Complete writeoff, except for the jet engine. I think the J model was valued at $100k+, while the prop was around $25k, which is all the coverage he had on it. Oops! I think this may have been author Richard Bach's plane originally.
I think one of the business partners died, and the company was moved north, to Oregon. A couple other similar businesses appeared over the years, but I think they may have gone away by now. Really neat plane. Still some original kits floating around, but ALL of them were missing various important parts that Bede had trouble building for lack of money, IIRC.
A word of caution. There were several versions of wings available originally. The -B wings were about 21ft, and the -A was about 14ft. I was advised by one of those partners, who did most of the initial test flying for customers, to never fly with the -A wings, as the stall speed and other handling quirks were deadly. The Jets were normally flown with -B wings cut down to 17ft, with internal mods for increased strength (doubled main spar, I think).
More on the wings:
There was one (of 4?) version available that had a (NACA?) profile that was normally only seen on some jets, and other high performance aircraft. The bad thing about that is it is pretty much not recoverable from a stall, at any speed. In other words, you stall, you bail.
That is a ground loving mother, but it looks like more fun than a basket full of kittens.
Speaking of the BD-5 series, I remember talking to one of my professors at Embry-Riddle about going to Oshkosh one year and seeing Jim Bede wandering around the flightline. He said he followed him around for a couple hours, because while the EAA had a hundred or so page rulebook, there was nothing in it that said you were prohibited from beating the tar out of Jim Bede if you could find him on the grounds, and he figured it would be fun to watch.
Why would anyone want to beat the tar out of him? What'd he do?
If your seriously thinking of doing this, might I suggest looking at Bert Rutan's brainchild, the Long EZ? Home-built, pusher-prop two-seater, top speed of 185, a canard wing design that handles supposedly like a fighter plane. Bill Whittle from PJTV has one, and loves it….
So Larry goes for a tank, you sure you don't want a decommed fighter or bomber?
So. Freaking. COOL! That's all I have to say, lol.
Turbine engines are expensive because the turbine blades are difficult to fabricate. CNC machines do not help much with this. The complex shapes of turbine blades make them difficult and expensive to manufacture by conventional means. However, 3-D printing may change this. 3-D printers can easily fabricate objects of complex shapes such as turbine blades.
I'm told that 3D printing is about the same state of development as computers were in the mid 70's. If so, we have not seen the revolution yet and it is likely to be profound.