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5540	10060	Hi there, welcome to my talk, Experimental Aviation Risks and Reward for the Aerospace
10060	14580	Village DEFCON 28 Safe Mode. I decided to do this talk with a little bit lighter content
14580	20020	than the stuff I did last year. Since those of us involved in security and variably are
20020	25000	also involved with risk, I thought it would be interesting to kind of apply the risk model
25000	29380	to some different perspectives. Since I'm building my own aircraft, I'll talk about
29380	34300	some of the things that I learned, some of the decisions that you will have to undergo
34300	39600	if you decide to actually get involved with building your own aircraft, and hopefully
39600	47400	give you a new perspective on this particular segment of DII and being a maker of building
47400	55980	your own airplane. So, again, my name is Patrick Kiley. I'm a member of the Penetration Testing
55980	63920	Team at Rapid7. Previously, I've done research last year on avionic security. There's a talk
63920	69200	that you can look up for last year's Aviation Village, before it became this year's Aerospace
69200	74680	Village, where I talked about CAN bus and avionics. I've also done other research in
74680	79760	internet-connected transportation platforms. I have experience in hardware hacking, Internet
79760	87460	of Things, CAN bus quite a bit, and I'm building my own airplane. So here's kind of a quick
87460	91940	overview of the agenda. We're going to talk about the FAA regulations very lightly and
91940	97340	specifically this 51% rule. We'll talk about plans and kits, a little bit on quick builds
97340	103340	as well. Composite versus riveted aluminum construction, you know, just kind of the construction
103340	109260	materials that you can choose to build your airframe out of. A little treatise on making
109260	115300	changes to tested designs, talk about engine selection, avionics, and then a little bit
115300	126530	about the final steps after you've completed. So the FAA defines the language for what is
126530	130710	permitted if you're going to build your own airplane. So certified aircraft have a ridiculous
130710	138090	amount of regulations they have to comply with for safety to ensure, you know, consistency
138090	142350	and everything else. And it's one of the reasons that makes certified aircraft so expensive.
143770	149210	Experimental aircraft are not cheap by any means whatsoever, but they are a little bit more
149790	158590	advantageous. The FAA defines the rules and federal aviation regulations 21.121 section G, and then
158590	164470	they've got an advisory circulator that they did 20-27 where they clarify some additional stuff
164470	169450	because of what some of the other manufacturers are starting to do. The biggest thing is you need
169450	175370	to have proof, you know, you need proof that you actually, this was built by a person and not a
175370	181890	company. So this is basically be taking pictures of your work, keeping a blog, keeping other records
181890	187750	showing that you bought the components, that you put them together, something showing your progress.
187750	193390	The work can be started by someone else. You can actually buy somebody else's amateur built kit and
193390	196650	finish it yourself. Of course, you know, cabbie and emptor, you don't know what their skill set
196650	202690	is, so you need to have someone who knows to kind of help review it and be able to actually examine
202690	208830	the work up till then and see if it's sound. And then you can also have help. That's how
208830	213710	quick builds work. There are a lot of programs where you can actually go to a factory and do
213710	217970	most of the work and then you just have the instructors there to guide you so you actually
217970	223870	comply with that 51% rule. A repairman's certificate is a little bit different. A repairman's certificate
223870	229150	basically allows you to work on it after it's done. So, for example, you can work on the engine
229150	234170	more and wouldn't have to hire an airframe and power plant mechanic. You can demonstrate
234730	240270	you have the skill to do the work safely and successfully. That's what a repairman's certificate
240270	245270	is. It's separate from the airworthiness certificate and it's a demonstration of the
245270	249730	skill, not a demonstration of the work. And experimental aircraft have restrictions that
250570	256610	don't apply to commercial aircraft. You cannot use an experimental aircraft in a for hire manner.
256670	260310	But if you're just moving yourself and your family around and you're not charging for it,
260310	266630	you're allowed to do that. You can basically use it for pleasure all pretty much within the
266630	269950	limitations. When you get the airworthiness certificate, your airworthiness certificate is
269950	274730	going to have its own set of limitations in it and it's going to be very clearly defined
275210	282250	as to what you're not allowed to do with it. Beyond that, the topic is very complicated and
282670	287050	I would just encourage you to do the research if you want to use an experimental aircraft in a
287050	293010	particular manner. There's going to be someone who has actually tried and done it and the answer is
293010	298910	going to be out there for you on the internet. So, why would you want to choose an experimental
298910	303250	aircraft? It can't be just because you want to fly. If you want to fly, you should just rent.
303250	307810	There are many things in life that you should rent and not own. Aircraft is probably one of
307810	312390	them, but if you want to fly something that's a little bit more higher performance and you're an
312390	318170	engineering nut and like to build stuff, this might just be for you. You have to be able to tolerate
318370	323830	a certain amount of risk. Building something that's normally done by professionals automatically
323830	329430	inherits a specific amount of risk and you have to be willing to analyze that, see what it is,
329430	333470	accept it. It's going to be probably the most complicated thing you've ever done
334410	338290	because you're not just doing the airframe, you're doing the avionics, you're doing the engine.
338670	343730	It's a lot of different disciplines mixed in together, but you can get a higher performance
343730	348190	aircraft than you would be able to get for a specific dollar amount. The image that I have
348190	353230	here of the Long Easy, it's a very high performing aircraft. It's also very reasonably
353230	358950	priced. It's a two-seater tandem. One of my favorites is you'll kind of see later when you
358950	364030	actually see that the kit that I chose to build, it's a very solid choice for an experimental
364030	370090	aircraft. So how are you going to build it? There are a few different ways you can go about this.
370090	375150	You can buy a set of plans. I actually have a set of plans here for my kit. This is a
375150	381810	set of Cozy Plans. It's a very thick, bound, large bound manual that also comes with some
381810	387530	very large format drawings. So this is some drawings of the instrument panel using
387530	393170	conventional gauges. And then, you know, that's just one section or two sections of the plans
393170	398930	that actually cover the whole thing. The other thing that you can do, and when you buy plans,
398930	404250	you actually just source everything. You're going to buy all the components. For example, this one,
404250	408410	it's going to be all the fiberglass, all the epoxy, all the individual metal components.
408410	413130	You're going to buy the engine, the airframe, the avionics, and you're going to build the
413130	417890	airframe from scratch using just plans. It's the least expensive option. It's also the most time
417890	425290	consuming. The way kits work is you purchase the plans and partially completed parts, enough to
425290	429890	qualify for the 51% rule. They have some quick builds where a lot of the stuff is done for you,
429890	435230	but you still have to finish it, and it greatly decreases the amount of time that you spend on it.
435230	441430	But you also increase the cost. The picture I have here is actually from Sun and Fun 2017.
441470	448210	It's a Velocity Twin. It's a gorgeous aircraft, very high performing, beautiful inside,
448210	453370	canard design, which you can kind of see my preference towards those already.
453610	457750	And then there's another thing called builder assistance programs, where you actually go to
457750	462010	the manufacturer and they help you along the way, but ensure that you're actually doing
462010	464770	enough to qualify for 51% of the work.
467450	470330	And then there's different materials. So if you're going to build an aircraft,
470330	476030	if you want just something low and slow, or maybe a small and single seat airbag,
476030	480170	the Fabric Overwood is perfectly valid. The very first aircraft were made from these. You
480170	488770	might have some just aluminum tubes, aluminum spars, and the rest of it's going to be wood.
489390	494250	It also can be very lightweight. And then you cover that with a doped fabric. It's a special
494250	502010	type of fabric that's coated in epoxy to make it very rigid, relatively easy compared to the other
502010	506690	techniques, inexpensive. This was just a gorgeous one that I saw at Sun and Fun. I'm not even sure
506690	512430	if it's fabric covered, but it's the type of aircraft that you'll see. Probably the most
512430	516890	popular style out there, the one that has the most examples flying, is riveted aluminum.
516890	522150	The Vans RV line of aircraft are all riveted aluminum, maybe with some composite components
522150	530230	that you add here and there. And that's how, for the majority of aircraft history, aircraft were
530230	535610	built. It was aluminum that was all held together by rivets. You have to be comfortable banging
535610	542610	rivets, working with blind rivets, but it's very strong and light. It was only recently that
542610	547850	aircraft construction moved towards composite, but you'll still see a lot of riveted construction
547850	556570	out there for existing airframes. And now we get to my favorite composite. So this is what I chose,
556570	564050	fiberglass and epoxy, or carbon fiber and epoxy. You can see a beautiful carbon fiber airfoil here.
566210	572330	What is composite? So really, anytime you combine two materials, and when those two materials are
572330	576710	combined, they form a stronger material, you get a composite. Concrete is a composite material
576710	581310	because you have your aggregate, your sand, and your cement, and you get concrete. Sometimes,
581310	586050	you know, with your reinforcing structures like rebar or other structures added to it,
586050	590990	but it's still a composite. So fiberglass by itself is not a composite. Fiberglass,
590990	597170	when it's bonded with epoxy, is a composite. Carbon fiber and Kevlar, not the bulletproof
597170	602910	Kevlar, but an abrasion-resistant Kevlar, are also a couple of other fabric materials that
602910	608990	can be used in composite construction. In fact, newer aircraft like the Dreamliners,
608990	620030	all composite construction. 777X uses composite wings and then conventionally fabricated fuselage.
621370	627130	So what I chose, the Burt Rutan design, this is a little bit about those, my favorites.
627450	634490	He pioneered moldless composite construction. So it's a method of fabricating fiberglass parts
634490	643510	without a mold. You take a section of foam, and I have an example right here. So for this image,
643510	648230	this is a section that was actually removed from the aircraft in a building. You can see you have
648230	656390	your fiberglass and epoxy layer, but beyond it you have sandwiched types of foam and they're
656390	664230	held together with micro bubbles mixed in with epoxy to bond both the fiberglass to the first
664230	669090	layer of foam and then the second layer of foam together. And what you do is on this other side,
669090	672790	you're eventually going to get foam on this. Not for this, this is a discard piece.
673670	679390	And between the two, by having this space separated by the two separate skins of fiberglass,
679390	683390	you get much stronger construction. And you can basically take those shapes, you can
683990	690330	lay them out, and then you lay the fiberglass on top of it into its final design. That was what
690330	695430	Burt Rutan successfully did in his very easy and his long easy, and he turned that into scaled
695430	701650	composites. And it now is going into space with that design. He just did Voyager, the aircraft
701650	708190	that flew around the world without stopping, and many of his other brilliant designs. He was a big
708190	714310	advocate of the canard. I think some of the the work has gone away from that, but I'll kind of
714310	720430	go into what a canard is in the next slide. But most of his designs were canard based.
720510	724410	Canards are very resistant to stalls. You still have to follow weight and balance,
724410	730550	and you always have to ensure that it's far enough forward so that the canard stalls first.
730550	735150	But a canard adds from lift instead of subtracting from it, as I'll kind of show you in the next
735150	741090	image. This is all from Bold Method. In a canard designed aircraft, the canard always must stall
741090	746170	first. If the main wing stalls first, you're going to enter into a situation called a deep stall, but
746170	749690	it's a relatively easy thing to avoid as long as you follow weight and balance, which you're
749690	756410	supposed to do every time you fly anyway. You'll never get into that situation. So a traditional,
756410	761170	conventionally designed aircraft, you have your horizontal stabilizer that provides
761950	768770	a vector of force opposite that of the wing. So it's providing, in this image, 250 pounds
768770	777410	of negative lift that counteracts the 2250 pounds of positive lift. And then in a neutral situation,
777410	781890	you have 2000 pounds of weight, you know, in this particular configuration. In a canard,
781890	787190	the idea is that it's more efficient because both surfaces are providing lift. Both surfaces
787190	793810	are providing a positive amount of lift to counteract the weight of the aircraft.
796170	802090	Again, all this composite picture of the skin I just showed you, where you basically have a very
802090	810410	thin layer of fiberglass embedded with epoxy. It's actually a very friendly method to get
810410	817510	into. Both the aluminum and the epoxy kits, they have what are called kind of like builder's
817510	823590	confidence kits. You're like, I'm not going to spend $10,000 on a set of components just to
823590	828510	see that this is really not for me. So you can spend just a little bit and they'll give you some
828510	835710	epoxy, some fiberglass, and some foam and you do it. You actually go through several steps to show
835710	840290	that this is actually something that you're capable of. In this other image, we actually
840290	847650	have a canard style wing that's for a COSY that's actually up on a jig before it has the
849310	858330	fiberglass applied to it. So this is where I got into the selection for the plans that I
858330	865490	eventually chose. So Bert Rutan designed the very easy and then he does design the long easy as a
866170	871910	ground-up redesign of that. Long easy is a two-seat tandem aircraft. These pictures are from
871910	878650	Sun and Fun 2017 when I took them. And then the picture you see here is that of an air canard
878650	883570	that's still in partial primer. I was really interested in this one because it's the design
883570	888730	that I originally chose to go with. And eventually I actually licensed the set of COSY plans as well
889590	894730	because I just wanted to make sure everything was covered. There was some disagreement between
894730	899190	Nat Puffer and the guy that designed the air canard, which is a slightly roomier version of
899190	906730	the COSY. So just to avoid any possible issues in design, I wanted to have both set of plans
906730	911930	because they're reasonably inexpensive. And I could actually decide that if something didn't
911930	920940	give me a clear image, I figured the other set of plans would. So here's the little blurb about
920940	925100	making changes. One of the biggest things I learned about from just looking in the forums,
925100	931720	talking to people, is that any changes that you want to make can have unintended consequences.
932200	936400	One of the earliest things I learned is like, you know, why wouldn't you not
936980	941020	take the fiberglass and use carbon fiber? It's reasonably cheap now.
941160	945600	Well, you're really not going to save a whole lot of weight, but you are going to introduce
945600	953520	completely different moments of elasticity. You could actually add some vibration elements that
953520	958440	could cause something to shear and cause something to fail and not anticipate it.
960100	964940	The other big line that I heard was basically, you know, from your aircrafts actually end up
964940	968260	being lighter because you're not going to be able to afford any avionics to put in it for after all
968260	971760	the money you spent on the carbon fiber. So you'll end up with a lighter aircraft that way.
974380	978160	It's pretty interesting when you actually dig into it and see that, you know, maybe not carbon
978160	982900	fiber is the best choice for all aircraft. There are aircraft that were designed around carbon
982900	989540	fiber. The Burkut, which is a fast and slick version of the Long EZ, is a carbon fiber variant,
989540	994720	but it was designed from the ground up to have the amount of carbon fiber necessary that it has for
994720	1000000	it. And then this is kind of a famous line from a plan. If you want to put something in your
1000000	1003860	airplane, first throw it up in the air. If it comes down, it doesn't belong in the airplane.
1004060	1008860	The designer of this was very minimalist in what he designed. He wanted this aircraft to
1008860	1014500	go without a battery. He wanted to go without a starter using just a prop start. Most people
1014500	1022120	have chosen not to do that. There are other issues and risks when you deal with hand cranking a prop.
1022820	1026160	You know, all it takes is a little slip of the foot and now all of a sudden you're, you know,
1026160	1033500	like the bad guy in Indiana Jones with a big fat spinning piece of metal right in your face. So,
1033500	1039400	no thank you. I'll pay the weight penalty and deal with the starter. And then with glass panel
1039400	1042600	cockpits, you need to have a backup battery source. You need to have a power source.
1042820	1047060	And if you're going to have a starter, you have to have a battery. But it just goes to show that,
1047060	1051020	you know, you really need to be careful when you're actually considering making changes.
1051280	1054620	Is this going to add weight? Is this going to change the wing loading? Is this going to
1054620	1060640	significantly change the performance characteristics of the aircraft? And here's really a case study in
1060640	1067000	this next example. The unfortunate accident that took John Denver's life. John Denver was
1067000	1075840	flying along easy. The NTSB actually found that the probable cause of that accident was the designer
1076400	1083980	decided to take the fuel selector valve and instead of it being in front in the area where
1083980	1092160	it's easily reachable by the pilot, he relocated the fuel valve to be closer to the fuel source.
1092460	1097020	But what that actually did is when you actually have to select it, you have to reach over your
1097020	1101680	shoulder because of the, you know, just you're kind of confined in. So you actually have to do
1101680	1106300	this maneuver to change the fuel valve. And then when he was doing that, they say he probably
1107780	1114020	unintentionally put control pressure on the rudder, causing a loss of control, causing him to
1114020	1123000	fly into Monterey Bay, taking his life. So just the thought, the designer, it's thought relocated
1123000	1126620	the fuel valve to make the fuel line shorter. By having shorter fuel lines, there could be less
1126620	1131980	risk of a fuel leak, but introduced other elements that were not necessarily reconsidered from the
1131980	1138300	fuel valve being up front. So in a long easy, the fuel tanks are behind you, the engine is behind
1138300	1144100	you. So the thought was let's put the fuel selector behind you as well. Maybe not the best idea. It's
1144260	1150740	a perfect example of the unintended consequences that you can have from actually making changes and
1150740	1156120	why you really need to take a risk-based approach to any possible changes than what the designers
1156120	1161160	actually intended on this. Because an experimental aircraft is inherently a risky activity.
1163060	1167860	That was a little section about engine selection. So when I was getting into this, I was debating
1168460	1178480	did I want to spend tens of thousands of dollars on an engine that was effectively a 50-year-old
1178480	1184100	design? And that's what they all are. All of the air-cooled engines out there are really based on
1184100	1191140	old, old technology. Pardon me. But they're designed for the purpose where they're used.
1191580	1195760	But the thing I quickly learned is that the problem you run into with automotive conversions
1195760	1202060	is, and the Subaru is a big popular one because it's kind of the same horizontally flat plane
1202680	1208340	opposed engine, you have all the cooling issues. You have to introduce some type of cooling system,
1208340	1214960	now you have a radiator, you have additional weight. You have to put in a reducing gearbox
1215520	1219680	to slow the engine speed down to the appropriate speed for a propeller.
1220040	1224300	That adds additional weight, adds additional complexity, additional points of failure.
1224900	1228500	And then you have to deal with the fuel injection system. A fuel injection system that
1228500	1234300	if you're using the automotive ECU, you may end up going to limp mode. And when you're in a car,
1234300	1238240	you can just pull over. In an aircraft, you have to find a place to land immediately if you lose
1238240	1244260	power. It can introduce an element of danger that's unexpected. And what I discovered is
1244260	1249560	they ended up not being cheaper. They ended up being heavier, more complicated, more prone to
1249560	1254360	more things that can go wrong. And because of all the changes you have to make there,
1254360	1259380	they end up not being any cheaper. So that leaves us with conventional engines. Okay,
1259380	1263460	you can do a turbine, but if you have that kind of money, you're going to be getting a super high
1263460	1270120	performance something anyway. So conventional engines, they are lightweight, they're expensive
1270120	1277700	for what you get. They are just look up IO 360 new and you'll see what I mean. Not to mention
1277700	1283320	things like an IO 540 or IO 540 turbo, you know, turbo normalized or, you know, some of the other
1283320	1287340	fancier ones. And imagine if you had an aircraft that had two of these, which you'd have to pay
1287340	1293980	for to replace them in. So there are experimental options. What that basically means, it hasn't
1293980	1299120	gone through the exact same certification process because the certification process itself is
1299120	1306040	expensive, but yet you get the same quality. So you can get an experimental version of these
1306040	1313280	engines that have the same quality for a much more reasonable price than buying something else
1313280	1320900	that would be kind of in the certificated realm. All right, avionics, one of my favorite subjects.
1321640	1326080	So when most of these designs came out, all you had choices were like, you know, your
1326080	1332240	little round steam gauges, as they call them. You have your individual airspeed indicator,
1332240	1337220	your horizontal situation indicator, you know, your compass, your turn and slip,
1337220	1344400	vertical speed, altimeter, all of your, you know, attitude indicator, all separate designs.
1345020	1351360	In a glass panel, you combine all that with a moving map, with GPS, all your controls in a
1351360	1354820	centralized point, but you're also introducing a central point of failure. So you need to have some
1354820	1362060	additional plans for that. But glass panel avionics are getting cheaper all the time. They're some of
1362060	1366340	my favorite things to mess with for those of you who've studied the previous research that I've
1366340	1373580	done. I think they're safer. I think they provide you better situational awareness. Even in, you
1373580	1377840	know, darkness, you're going to be able to see the terrain in front of you if you have a more recent
1378960	1383140	system. So you're going to be able to see that because it's going to have the terrain database
1383140	1387540	loaded into it. You're going to see that there's an antenna tower loaded and I have to refer down
1387540	1392240	to a sectional chart and manually de-conflict. The aircraft is going to tell you that there's
1392240	1399840	an issue coming up. All your approach procedures are going to be built into a database within the
1399840	1405780	avionics. But what I feel that these need are some backup gauges. Now they have electronic backup
1405780	1413660	gauges, but why not look for something that is reasonable and inexpensive and just use a couple
1413660	1421620	of must-have backup instruments as your backups next to your steam gauges. I think that's the
1421620	1430520	best way to go. All right, so a little blurb on avionics cost. And we're going to take the Garmin
1430520	1437040	G3X for example. They make certified and experimental versions of the exact same display
1437040	1444860	running the same firmware. Just it's been blessed by the FAA and received certification approval.
1445480	1453400	$99.95 for just the display. That's without any of the instruments, without your magnetometer,
1453400	1461800	without your airspeed sensors, your various electronic gyros, any of your engine instruments.
1461800	1468120	$10,000 just for the display. Whereas the exact same experimental display is $3,895.
1468460	1475920	So my opinion, best choice in avionics. What I like, the ones that I've actually displayed
1475920	1480160	them for and they're not mine. I've just done research on them. But experimental glass with a
1480160	1483800	emergency backup steam gauges is a great combination.
1485740	1490920	Okay, so now that you've done this, you've actually built your aircraft, what's the next step?
1490920	1495640	You have to get a special airworthiness certificate. So what you do is you work with
1496680	1503360	what's called a DAR and you have it inspected and you get an airworthiness certificate that tells
1503360	1508860	you you have to fly for 25 to 40 hours in a restricted area away from population. You have
1508860	1515860	fly out of a special airport that's away from everyone else. And you have to basically fly off
1515860	1521780	the number of hours to show that this aircraft is worthy to be operated on the same runways and
1521780	1528120	areas that other aircraft operate. And if you DIY this, you effectively you are a test pilot.
1528740	1533240	But there are people that you can hire for this. If you are not,
1533240	1537020	you know, this is a level of risk that you don't necessarily want to undertake. There
1537020	1540600	are people that you can hire that love to do this all the time that are very skilled,
1540600	1545740	especially maybe for your particular airframe. But effectively what you have to do is you have
1545740	1549640	to build a test plan. Same thing that test pilots would do. So the first thing you do is you fire
1549640	1554580	up the engine, you test everything. Then you taxi around in a little bit, shut everything down,
1554580	1560160	inspect everything. Then you undergo high speed taxi testing where you actually get almost up to
1560160	1565740	flight speeds and then slow back down again. And then you have your first flight. And the biggest
1565740	1570620	things I see in the plan sections are when you do this, you need to wear a parachute.
1571480	1576540	I guess that assumes you need to have taken skydiving classes, but I guess any parachutes
1576540	1581300	better than any parachute, even if you haven't been through this stuff, is better than not
1581300	1585600	wearing one if you need to get out because you've gotten into an uncontrollable situation.
1587180	1591200	But this is kind of like probably one of the most risky areas of flight. It's where a lot of the
1591200	1596640	accidents happen because something was tinkered with, there were unintended consequences, and
1596640	1603760	that's where disaster struck. So thank you. I think we're gonna have some Q&A after this,
1603760	1607760	so we'll cut over to that. And please feel free, I look forward to your questions.
1607760	1609420	Thank you for listening to my talk.