One man designed and built the ultimate bush plane | Hacker News Reader

One man designed and built the ultimate bush plane

arstechnica.com

252 pointsprivong80 comments

As someone who does this kind of work, the timeline is absolutely insane. The aircraft started out as a PZL-104MA Wilga 2000 but he redid part of the wing, built an entire carbon fiber cowling and redid the wiring, all on top of the engine install, though that and the carbon fiber he had fairly extensive previous experience with. One thing you'll notice if you watch the build videos is he makes extensive use of very complex CNC machining for the wing tip extensions and some other odds and ends. I would be very interested to know how much risk management went into the design though, as on the surface DRACO and Turbulence (his other PT-6 project) seem to have a lot eyeball engineering going on as neither airframe was ever designed to handle the flight loads that the engines put on them. There's only so much you can see in YouTube videos though so I'll give him the benefit of a doubt.

Insane timeline indeed! I wish I had a work ethic like that. It's interesting how he tells that as a child, he was encouraged by his parents to "always finish his project, no matter how much you disliked it".

I wonder what the reliability of this beast is like, but I guess only time will tell.

If anyone is interested in this kind of stuff (fiberglassing fuselages, building cockpits...), Peter Sripol, a model plane enthusiast, made his own DIY plane that can carry a human with hobby grade brushless motors: https://www.youtube.com/watch?v=eNSN6qet1kE

> "always finish his project, no matter how much you disliked it".

Yeah, I wish my parents would have taught me this when I was young.

You're never too old to learn.

Well I never learned it until the pain and waste of unfinished projects pushed me. This talk by John Carmack was encouraging too. He talks about the importance of finishing projects: https://youtu.be/vlYL16-NaOw

About 2 years into an RV kit build, so I’m pretty jealous of this guy right now. Fantastic airplane he made! It would have taken me 5 months just to tear the old one apart.

He has/had a prototyping company. The plane didn't take him 5 months, it took him his whole life thinking and only 5 months execution.

He still executed a tremendous amount in five months.

Speaking of crazy timelines, Robert X. Cringely attempts to build a plane in 30 days in the documentary Plane Crazy:

https://www.imdb.com/title/tt0164814/

https://www.nytimes.com/1998/07/22/arts/television-review-th...

I remember watching that on TV. IIRC, he failed totally with a fibreglass design, cut it up with a chainsaw in a rage, then went and found some people who actually know how build planes out of wood properly. And still failed the deadline.

This is very cool. I had to look around a bit, but I found a link to DRACO taking off at at a competition:

https://www.youtube.com/watch?v=Hp3402SOk8A

Apparently this distance is about 100ft.

Stats are all over the place, but "DRACO will climb at 4,000 feet-per-minute (FPM) and cruise at 180 mph (290 km/h) at 16,000 feet." which apparently blows everyone else out of the water (and it should for a 1M+ plane)

Also, 5 months is a crazy timeline to build something that flies. I can't imagine the amount of skill (and confidence needed in your skill) to hop in a plane you tore apart and redid in less than 1/2 a year.

Go watch the build videos and you'll understand how he got it done in 5 months. The guy is definitely "special" in the sense that he's incredibly driven, very positive, and a bit scary.

Apparently, he only sleeps a few hours a day.

The playlist is here [0], and it's definitely worth watching! The completed plane is just insane, and I was amazed at how much of it he made from carbon fiber.

0: https://www.youtube.com/playlist?list=PL9OFkVHYEhoEfWmN0lQRZ...

That's astounding.

This guy is super inspiring to watch. I'm probably the same age as he is and haven't accomplished a tenth of what he appears to have gotten done. But just watching him it's clear why, he just goes...

Not only is this really impressive, but it also sounds like that whole hanger is his. Of course you have to have money if your hobby is planes but look at what else is inside the hanger, that's incredible. And the view outside the hanger door windows is unobstructed mountains. Doesn't get much better.

>Apparently, he only sleeps a few hours a day.

I look forward to the day that that particular trick of genetics is discovered. It took me about eight years to accept that a small percentage of the population is just born with that gift, and that trying to emulate it by restricting my sleep hours was only hurting me.

Don't underestimate the enormous amount of perpetually sleep deprived people who tell themselves that they have that "gift" but don't.

And don't underestimate the damage such people can do.

That short take off took me totally by surprise. That's not even 100m

110ft is cited by Ars.

Which is 33.5 meters.

One of the 2017 competitors took off in a little over a tenth of the distance DRACO took[1]. Of course, a stripped down Cub is probably much less useful overall, but taking seeing it take off in ~14 feet is fun.

[1] https://www.youtube.com/watch?v=Bo7-BuNiP6Y

The wind is also a significant factor. But yeah, that's almost a helicopter :)

If you want to see truly insane performance (not that DRACO isn't impressive), look videos of fighters like the F-22 doing max performance take offs. Lightly loaded they can be off the ground in about 250m and supersonic before the end of the runway - and these are aircraft that weigh upwards of 20 tons.

I watch a few aviation YouTube channels and this plane has popped up a few times. I had no idea of the story behind it, that is super cool!

Minor article nitpick, bushplanes are more like the Land Rover Troopy or Enduro motorbike bike of the sky, and not at all like an SUV. SUVs are lumbering, fragile and impractically large people busses, often with all the luxuries you can think of. Bush Planes are nimble, barebones, and pragmatic vehicles of utility. Getting hot? Crack the window. Luggage? Not today sorry, the air is too thin.

Except this one, still a bush plane, just an incredibly powerful one!

I definitely agree with bush planes being pragmatic vehicles of utility, and are generally stripped down pretty bare. But I've heard more than one bush pilot refer to his plane as the SUV of the bush, generally these were larger planes like Beavers or a 206 though. Seeing a full size fridge placed sideways in Beaver (with the doors removed and the ends sticking out either side) and you'll see why that say that!

Then there is the deuce and a half [0] of bush planes, the Pilatus PC-6 TurboPorter [1]. Consider the consequences of an engine outage anywhere in this video [2].

[0] https://en.wikipedia.org/wiki/M35_series_2%C2%BD-ton_6x6_car...

[1] https://en.wikipedia.org/wiki/Pilatus_PC-6_Porter

[2] https://www.youtube.com/watch?v=oY0ojYeoNmE

Are there even any SUV out in the bush?

Yes. For folks doing normal stuff, the bushplane is a tough motorbike. But most people who use them use them for survival, which means they have work to do -- a lot of work. If you can't haul it in a bush plane, it's not getting in or out, so they're the SUV of the bush.

I've heard that for the old 206's, if you could fit it through the doors you could haul it. (Insert long discussion here about that being a good way to kill yourself. Presumably there's some bush wisdom to prevent that from happening)

Could you list some of those aviation channels?

Woo, turbines are great; fantastically reliable, awesome power-to-weight, able to use cheaper and safer fuel than gasoline piston engines. They are pretty expensive though, wikipedia says the PT6 used in this project starts at around $500K.

There's a few companies designing smaller turbines (100-200 kW size) for aircraft, http://www.turbotech-aero.com/ and https://www.turb.aero/ , competing with Rotax 912, Lycoming, Continental. Guess we'll see if the promises of lower costs come true.

There's also a few companies making diesel aircraft engines, AFAIK these have seen some success in Europe where 100LL is crazy expensive.

Maybe GA is, ever so slowly, entering the jet (fuel) age..?

You can buy -28 PT6s for $150-200K with fresh hot section inspections, lots of time/cycles left on the rotable parts, and time since overhauls in the few thousand hour range. New they might be $500K, but no real reason to buy new vs used and inspected.

Plenty of the small PT6s coming off older airframes for -135 upgrades or airframe retirements.

This is awesome and all, but even a used PT6 turbine is a lot of money. If I were the sort of rich person who could afford this, I'd be looking at turbine-retrofitted DHC Beavers and Turbo Otters instead.

For example the Viking Air rebuilt turbine beavers:

https://www.vikingair.com/viking-aircraft/dhc-2t-turbo-beave...

The company making diesel engines was Thielert, which eventually went out of business. Most notably, they were available in the Diamond DA-42. IIRC, they consumed 7GPH each at cruise, which is roughly half the consumption of Draco at the same speed.

They were bought by a company in China and are now being marketed in the US by Continental. There are STCs for many Cessnas, which seems like a pretty appealing option.

http://www.continentalmotors.aero/diesel/diesel-engines.aspx

This interview with him is amazing https://www.youtube.com/watch?v=PqhI4MeCn1c

To have the money AND the skill and what an amazing attitude!

The video highlights all the changes he made- including lights from a 737 :D

I couldn't stop watching Mike's build videos. This guy has an infectious Steve Irwin level of enthusiasm for aviation

And getting shit done. His fist pumps are like a drug haha.

It's an impressive achievement, but I would say the true beauty of good engineering is in being the best while also keeping costs under control. Getting 50-80% more performance isn't hard when you cost 5x as much (or more).

And most true in aviation. With enough funds you can buy some very magical things. But it isnt a bush plane if it cannot be fixed in the bush. Things like turbines and carbon fiber dont lend themselves to repair in an actual field.

Carbon:

One of the most popular high performance light bush planes at the moment: https://en.wikipedia.org/wiki/CubCrafters_Carbon_Cub_EX

Turbines:

The money makers: https://en.wikipedia.org/wiki/De_Havilland_Canada_DHC-3_Otte... (plus it's twin cousin)

https://en.wikipedia.org/wiki/Sherpa_Aircraft_Sherpa

So these aren't bush planes?

Edit: further, there's nothing inherent to carbon or turbines that make them unsuitable for the backcountry. Turbines are generally more reliable and have fewer moving parts. There's nothing on them that you can't fix with bailing wire that you can on a piston engine. The Wilga is overwhelmingly aluminum monocoque but if you need to fix the cowling (the main carbon part) some speed tape will do as it's not really load bearing. The cessna I took my checkride in was probably missing half it's cowling bolts :/

Not to mention all the Basler-converted turbine DC-3s, many of which are still flying into the least hospital places on earth (like Antartica) at almost 90 years old.

My worry with a turbine on a bushplane would be the potential for it to ingest gravel / sand / rocks etc.

Surely a prop is better suited for this? You could even carry a spare "just in case".

Piston engines have air intakes too. A 600ish HP turbine is also moving a lot less air than you probably think.. it's not a high-bypass jet on an airliner.

Small/medium sized turbines are used all the time on helicopters, which routinely see backwoods operation.

These are turbo-props. The jet bit is only a power supply to turn a propeller. It doesn't provide thrust like in a 747 or military jet. Its air intake is covered by a filter system just like any piston engine. For a given fuel consumption, the amount of air moving in/out of a turbine engine is roughly proportional to a piston engine.

They certainly do push the limit of what I'd call a bushplace. Are we going to define anything that lands on grass a bushplane? They operate in the woods, but can they actually live in the woods? Turbines need to be sent away for servicing and are very expensive. They cannot be disassembled or inspected without things like bore scopes. These are the planes that service logging camps, commercial operations, and fly back to aerodromes. They aren't the romantic planes servicing trappers or individual prospectors, the ones that sleep under a tarp most nights.

The exact same thing is true of any certified piston engine but on a shorter time table. Piston engine need to be removed and overhauled at the factory every 2000 hours and if a prop blade grazes the ground or hits a bush it needs to be removed, fully disassembled and have a die penetration test done at a minimum.

Also, a bush plane is, by definition, any logistics aircraft that doesn't need a runway which those very much fall into.

Carbon fiber can be fixed in the bush. What's special about turbines that makes the not field repairable? Nobody is fixing engine cores of any type without flying in parts anyway.

If anything turbines are probably better... I mean, worse if something actually goes wrong probably but there's less to go wrong.

The thing is that turbines are incredibly reliable compared to piston engines. The PT6 in particular is known for reliability. Compare the TBO (time between overhauls) on the IO-540 piston engine originally at 1200 to 2000 hours depending on application to the TBO for the PT6A turbine which is 6000 to 9000 hours depending on model and application. In any case, fixing an aircraft engine in the bush is not really a thing, the concern is forced landings due to engine failure.

In airline service engines are monitored and inspected and overhauls are done when there is evidence that it is needed. One CFM-56 on a 737 went over 40,000 hours before being removed from the airplane for rebuild.

The extreme reliability of turbine engines is why they permit twin engine airliners to operate on routes that could require up to 370 minutes of single engine operation. That is, the FAA considers the risk of a second engine failure is acceptable for over six hours. [0]

[0] https://en.wikipedia.org/wiki/ETOPS

This is an expensive plane, but $1M isn't that expensive for a plane. It's would be like buying a $80k car.

It's very expensive for a 4 seater.

The current most popular 4-seater, the Cirrus SR22 goes for about $600k-750k new depending on options.

Even the turbine-power Lancair Evolution comes in right around $1M, and that's for a fully certified-factory built aircraft.

The aircraft in the OP is an expirimental (e.g. you can't make money using it) aircraft and the quoted price did not include hundreds or thousands of hours of labor.

The Luftwaffe Storch was the granddaddy of these designs:

https://en.wikipedia.org/wiki/Fieseler_Fi_156

I would argue that the Piper Cub, and subsequently the Super Cub, were the predecessors of modern bush planes.

The Storch was specifically designed with STOL in mind and for very rough runways.

I've seen one flying backwards on an air-show. It has an extremely low stall speed.

Apparently the Antonov An-2 [1] can also fly backwards. There is no published stall speed in the flight manual and realistically it's around 25 kt (50 km/h).

[1] https://en.wikipedia.org/wiki/Antonov_An-2

Fun fact, Antonov was responsible for the Soviet effort to copy the Storch, years before designing the An-2.

AN-2 doesn't stall (with power on)... it just mushes and descendeds at a few hundred feet per minute. Emergency procedure is to just hold the stick aft and give it power. Almost like descending under a parachute.

An article about bush planes, but no mention of the beaver? If you cannot strap a canoe full of beer under it, it aint a bushplane.

One man designed and built a one million dollar impractically expensive and powerful bush plane plane for his personal use. Very cool, but way way over the top.

The largest single cost was the $400K+ engine that allows him to take off in a very short distance as well as fly extremely high for this type of plane. He added oxygen, and numerous improvements.

I've seen a man created a drone for transportation

https://www.elitereaders.net/flyingkyxz-flying-drone-car-phi...

How do STOLs compare to helicopters in pros & cons? Especially regarding costs? I'm curious if it could be feasible to operate a STOL as an air taxi service in a city, could it be cheaper than helicopters?

Helis are a maintenance, relyability and cost nightmare. You only use them when you have to.

For some footage, check out Trent Palmer's recent series of youtube videos of his journey to and from Oshkosh with a group of bush planes across the US: https://www.youtube.com/watch?v=pqhuK4JnA4E&list=PL6JekVPw0E...

Lots of awesome footage of these people landing in all sorts of crazy places. Also some videos about this plane and its owner.

Being an airplane/aviation aficionado I really like this kind of stuff and the amount of time and effort that went into this "prototype", but I can't get past one important thing... it cost 1 million to modify it!!! Given enough money and time, people can build anything :-)

Interesting. I would have expected bush planes as needing more cargo space that this plane appears to have.

The PT6A-28 is also a surprising and interesting choice... though I suppose once you get past the idea of not using a piston engine, it's less surprising.

This is actually quite big by bush planes' standards.

watching his videos are eye opening, amazes me what can be done with modern technology and experience.

googling aside, are there resources on how to start with carbon fiber?

detailed series how to make a carbon fiber hood (from a company that sells "carbon kits"):

https://www.youtube.com/watch?v=UgKvDw1E60E

i wonder if he considered an electric motor. no horsepower penalty for high altitudes with that. just the battery problems..

There are plenty of folks experimenting with electric bush planes, but they are more like electric tricycles with wings and a chair at this point.

any links?

Battery problems for planes are huge. Atleast for a big plane like a 787 MAX the battery to achieve same performance would easily weigh more than the aircraft by an order of magnitude.

I imagine even for bush planes the battery weight will be immense due to the much much lower energy density (it's about 2-3 orders of magnitude and you loose fuel while you fly, batteries don't change weight when discharged).

edit: electric motors do have penalties for high altitude, notably the reduced pressure will make cooling less efficient and reduce the maximum power output (though generally your efficiency overall should remain stable and normal)

yes, battery issues are a challenge for electric planes: https://www.wired.com/2017/05/electric-airplanes-2/

however, but they are not insurmountable, and many people are doing it:https://spectrum.ieee.org/aerospace/aviation/cheaper-lighter...

also, the high altitude penalties for electric motors are completely negligible. cooling efficiency for an electric motor has nothing to do with power output.

>The turbine Mike had in mind was a 680 shaft-hp Pratt & Whitney PT6A-28

This pretty much removes any part of "engineering challenge" there

A turboprop? On that small a chassis, volume-wise?

I wonder if he gets even a full hour of flight time from a full fuel tank...

If you watch the videos he adds some fuel capacity. The particular engine he's using isn't horrible on fuel consumption, particularly at altitude, though definitely worse than the original IO-540

It's really not that unusual these days...

Consider the Lancair Evolution https://www.evolutionaircraft.com/

Turbines can actually acheive better specific fuel consumption (lbs fuel/hp/hr) than piston engines when operating at high power... it's actually at _low_ power settings that they really suck fuel wise.

He said he actually has better fuel economy with this engine than with the original, because he can quickly climb where air is less dense and cruise at that height at low throttle.

It probably helps that the original Wilga is very fuel-hungry, it's basically a flying tractor :)

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