The world of experimental self-built aircraft is full of oddities, but perhaps the most eye-catching of all is the JD-2 “Dyke Delta” designed and built by [John Dyke] in the 1960s. Built to copy some of the 1950’s era innovations in delta-style jet aircraft, the plane is essentially a flying wing that seats four.
And it’s not just all good looks: people who have flown them say they’re very gentle, they get exceptional gas mileage, and the light wing-loading means that they can land at a mellow 55 miles per hour (88 kph). And did we mention the wings fold up so you can store it in your garage?
Want to build your own? [John] still sells the plans. But don’t jump into this without testing the water first — the frame is entirely hand-welded and he estimates it takes between 4,000 and 5,000 hours to build. It’s a labor of love. Still, the design is time-tested, and over 50 of the planes have been built from the blueprints. Just be sure to adhere to the specs carefully!
It’s really fun to see how far people can push aerodynamics, and how innovative the experimental airplane scene really is. The JD-2 was (and probably still is!) certainly ahead of its time, and if we all end up in flying wings in the future, maybe this plane won’t look so oddball after all.
If you fancy saving some hours (and likely money):
https://sky4buy.com/144080149926/020298
(Not sure if it’s still for sale.)
Of course, buyer is responsible for making sure they are not inheriting the mistakes of others….
$500 just might be worth the gamble.
(But not for me)
They don’t tell you how the previous owner passed away. If it happened while he was testing his craft, then thanks, but no thanks.
For my father’s generation building and flying aircraft like this was a rite of passage, and not all of them survived the process. How times (and people) have changed.
Nope… that term was reclaimed long ago. One organization even fought the PTO to register a trademark using the word. The battle with the PTO was really interesting and the registrants built a very compelling case based on other trademarks the PTO had issued without controversy.
https://en.m.wikipedia.org/wiki/Dykes_on_Bikes
Standard version has a 180 HP engine. A Tesla motor generates 283 HP. Stick some batteries in the wings and off you go! Maybe.
Some batteries?
The 40 gallon fuel capacity of a Dyke gives you 240 pounds credit, maybe another 50 pounds in the tank itself.
The lycoming o-360 weighs in at 258 pounds.
So youve got 548 pounds for motor, inverter, bms, and batteries.
The lightest tesla battery weighs around 1,060 pounds
Might want to rethink your plan.
A US gallon of gasoline is worth 10 kWh in terms of batteries, approximately. In well optimized engines, it can produce up to 15-16 kWh.
Lithium-ion batteries achieve 250 Wh/kg on the cell side, and about 100-180 Wh/kg as a system with cooling and armoring and wiring – the whole battery pack – so the equivalent mass to a gallon of fuel is about 50 kg. This of course varies with different sizes of batteries.
It used to be that batteries had a 30:1 disadvantage to fuel. These days with more advanced chemistries available on the market it’s “only” 15:1 weight penalty in general. You can get around it somewhat by stripping the battery of all safety features and protective coverings, and running it at higher charge voltages – like in drones – but you’ll burn through batteries quickly and that becomes mighty expensive in the long run.
Hmmm.
By my calculation, the 40-gallon-equivalent battery weight is
40*(conservatively)10.000 Wh/(250 Wh/kg) = 400.000/250 kg = 1.600 kg = 1,6 t.
Am i wrong there?
Sure, you’re mixing SI unit with imperial units. And you don’t account for the weight of the thermal engine vs the weight of an electric motor.
The equivalent of an “engine” for electric vehicles is the motor-inverter package with the built-in reduction gear. The copper bus bars and thick cables to the battery, plus all the other stuff actually weigh a significant portion of what an engine would weigh. You still need all the coolant pumps and reservoirs, hydraulics pumps, radiators, fans, and auxiliary (12/24 Volt) power systems to be there.
Take a look at a Nissan Leaf’s power unit. It’s literally as big as a regular economy four-banger.
https://www.youtube.com/watch?v=2o-hfJw2fMI
“The inverter weighs about 40 pounds.
The gearbox is about 58 pounds.
The charger/DCJunction box is about 70 pounds.
Total unit altogether was around 300 pounds.”
It’s a total myth that an electric drive-train saves any weight over a gasoline engine. It can, but it won’t.
>Am i wrong there?
It’s on the optimistic side.
A Tesla Model 3 75kWh pack weighs 473.55 kg so the 40 gallon equivalent pack constructed in a similar manner would be 2.5 tons. Of course there would be some savings by removing redundant structures, but overall I’d be happy to get it under 2 metric tons. The reason why electric cars get comparable ranges these days is by highly optimized aerodynamics and rolling resistance, which is a fickle compromise of tuning for particular driving conditions and styles – namely, the EPA range testing conditions.
This is why electric airplanes generally don’t get off the ground – or they have significantly shorter ranges and almost no payload capacity besides the passengers.
>you’re mixing SI unit with imperial units
A gallon is just a convenience unit that is equivalent to 0.0038 m^3, just like the liter is not a SI unit but a convenience unit equivalent to 0.001 m^3. The SI consists of meter, kilogram, second, (Ampere, Volt, Pascal…) and their derived units – which does not actually include hours, liters, bars, etc. and their derived units. A kilowatt-hour is not a SI unit either – though it is considered a metric unit.
Tangentially: I wonder how (if at all) significant the diminishing weight of the fuel is. At some level, the load becoming progressively lighter must make some difference.
For most subsonic aircraft configurations, induced drag contributes about 50 percent of the total drag of the aircraft throughout its flight profile. Induced drag is proportional to the lift, which for most of the flight of the aircraft=weight. So you can imply from the fuel weight/GVW of the aircraft what the effect will be. You are a couple of steps away from converting that number into a change in range (you would also have to have engine fuel usage for various power settings and also know something about the prop), but I would think those are the initial steps. I would think the effect is significant. (source for the induced drag percent: https://www.sae.org/publications/technical-papers/content/892341/)
Unless you want to make your plane an anchor, no. If it was only remotely challenging Tesla would have done it. But for sure you did not try yet all the possible places to stick batteries ^^?
Or you can forgo the batteries entirely and use a cable…
If there was any design that screamed for a conversion to composite molding, this might be it. Of course if you’re going to go to that much trouble, why not just join the Rutan Clan and put together a long-EZ or Defiant?
Pro tip: it’s way easier to fake your own death when all your acquaintances know you’ve been building a plane in your shed for 5 years
the center of the home built airplane universe is here
https://www.homebuiltairplanes.com/forums/
many,many,many different designs exist
need an account,and a good atitude to sign up
which may still be free
While a 4 seater is cool. it would require a full pilots license
Scaling down the design to a tandem 2 seater weighting 600 kg (1,323 lb) or less for eLSA would make it a bit more accessable
It would be nice if they would bump the unlicensed ultralight weight limit up a bit, Theres not much you can do with 254 lbs.
Does the current Unlicensed Ultralight 254 lbs include pilot, passengers & cargo ?
Nope
The 254# allowance doesnt include fuel (5 gal limit), Floats, or safety devices either
In the US ultralights arent allowed passengers. Single seaters only.
Cool.
But it’s not a flying wing.
It has a tail, which makes it a lifting body aircraft.
Will FAA allow me to land this thing on any public airports?