FLYING my Homemade electric airplane

[@xliquidflames]

Anyone that says these projects are useless is just being a grumpy, jealous, killjoy contrarian. You're learning, teaching others, having fun, entertaining people, and you're doing what you love. It's not useless at all.

[@Alex-co7cq]

It sounds like the only useless things are their dumb internet comments.

[@hrhodes2768]

also it literally doesn't matter if the projects are useless they're fun for him and entertaining for us there's no real reason for him not to build them

[@twentylush]

thats hba for you

[@calvingarrett3245]

I agree with you on that one he does a lot of learning things plus entertainment at the same time it's giving me more ideas than I could think of in that little stunt they pulled over the Perry lighter and the airplane with a guy touching his feet on the wing was pretty cool little risky but at least it was a good calm day but yeah these deadbeats like criticize you know they can take a chill pill and watch something else if they don't like this guy's videos I find them very knowledgeable and entertaining and and inspiring I've been watching this guy Peters videos for quite a while until there has been some that I haven't seen yet but he's a pretty smart young man seems like a really good person anyway thank you Peter if you read this comment for entertaining us and giving us knowledge and more understanding how things work when it goes right or wrong. Stay safe out there Peter and God bless you. Watching from Roseville California USA

[@simpilot001]

True man

[@BobbyDukeArts]

You're really making me want to build an airplane, Peter. Great video

[@mininara6471]

Id watch that

[@hafizfikri1108]

make sure u build it from wewd

[@duskintheforest584]

Yeah dammit.

[@ofroaderboi]

yes

[@ashadowawhisper]

Wick’s Aircraft Supply or Aircraft Spruce and Speciality both have plans for aircraft.

[@carlschannel]

0:58 oh phew 😮‍💨 thanks for clearing that up for us, I’m not a plane guy but this explanation really cleared things up for me

[@shawndcummings]

I love it. It reminds me of WWI aircraft and how simple and pure flying was in the early days of aviation. That is a lovely craft.

[@RCGemblung]

yeah you're right

[@shlokshah5379]

Did you just said fun and simple to those people who made them. Now everything you need to make a plane can easily be available however even finding engies for planes was hard those days. Motors are so efficient now that even a 5v motor can make a small plane fly easily

[@Srfingfreak]

I highly recommend Ivoprop adjustable propellers. They can in-flight adjust and have slip-ring kits for easy install.

[@orvjudd1383]

I like your idea but FAR 107.3 requires only a fixed pitch or ground adjustable propeller for ultralights.

[@tenlittleindians]

@@orvjudd1383 He's got a pilots license so he could always register it as experimental and then play with the IVO Prop's in flight adjustable propeller.

[@RCGemblung]

yes me too

[@jobes8315]

@@orvjudd1383 FAR 107.3 covers definitions for UAV's, FAR 103 covers ultralight aircraft and I didn't see anything in there that states they must have fixed pitch propellers

[@lr21643]

Wouldn't an in-flight adjustable prop be heavy? Weight is critical on an ultralight like this one.

[@PsychoticWolfie]

STEM educators (that includes maker-KZbinrs) are some of the most valuable people in society IMO. Right up there with other essential workers. Who else is going to get kids and young adults into innovating for the future? Every one of your builds are more important than anything any critic has to say!

[@tejaspatil2791]

I was literally on the verge of giving up engineering as my major...but you inspired me to keep going. Thanks peter

[@TheDro]

that was beautiful! wish i could have been there to see it in person!

[@ChauNyan]

That's wicked, dude!

[@furonwarrior]

I believe he shows it off at FliteFest.

[@RCGemblung]

superb and amazing

[@Weisz]

“”””sOlAr pOwErEd”””” jk, glad to see this thing flying at it’s best 👍🏻

[@eekee6034]

It's solar powered in the same way a horse is solar powered. ;)

[@sr.luisraytraceiii2422]

Sulfur Batteries in the future will make batteries lighter and powerful! Solutions...

[@PlasmaChannel]

This is definitely your best video yet. I enjoyed the casual setting.

[@Kit-yv7ob]

Yeah, the click bait title was unnecessary.

[@zilog1]

same

[@Lordofhogs]

i personally enjoyed the rc crane flamethrower video but this one was good too

[@Andithemago]

I dont agree because he didnt build or show antthing new, he just flies something he built a long time ago.

[@Voyajer.]

@@Andithemago He showed the paramotor stunt...

[@gabedarrett1301]

Everytime Peter uploads, I've always wanted to build that project for myself. Excellent work, as always! Also, I have a video proposal: getting a quadcopter to fly as quietly as possible

[@jaysaini955]

0:17, these people are insane

[@eekee6034]

There's usually a tradeoff between noise and efficiency, I believe. In nature, owls are the quietest fliers, but they a long way from being distance champions.

[@gabedarrett1301]

@@eekee6034 Actually, I've heard that large, slow propellers are quieter _and_ more efficient

[@eekee6034]

@@gabedarrett1301 Oh interesting!

[@Wrublos212]

@@eekee6034 Indeed. Compare 2.5" hi RPM propellers versus 10" low RPM ones.

[@FactionalSky]

Building what you want can never be useless. You are learning and kind of teaching. It is woth it.

[@just_bored3467]

Peter, please be careful paramotoring, grant from TKOR passed in a paramotoring accident, and we don’t need to lose you either, be careful!

[@ConnorwithanO]

It would be interesting to see how far you could extend the range using thin-film solar panels on the wings. Probably a few minutes or less, but an electric plane needs everything it can get.

[@nicerides9224]

Maybe a small turbine generator behind the prop to help recharge as well. I saw a video ages ago where someone had a solar powered plane. It was more glider proportions though.

[@error.418]

The extra weight would offset the gain

[@professorvaudevillain]

Not to mention that would allow it to (slowly) charge wherever you land!

[@ParallaxScene]

@@nicerides9224 That's not how that works...

[@PnwPryo]

@@ParallaxScene yeah it is

[@Maximum_777]

I think the simplest improvement you could do is reduce drag, there's a bunch of little places, around bolts, your rudder pedals and boots, various connection points for things, etc, where I think little 3D printed more aerodynamic caps and things like that could be implemented to reduce drag. Every little thing counts when it comes to drag like this and you probably could help your battery life a decent bit with simply reducing as much drag as possible.

[@GRAHAMAUS]

It also seems to fly at a high angle of attack, which must be super draggy. Not sure how that can be overcome -- move the CG rearwards (or should that be forwards) a little? A flatter attitude would do wonders for the performance.

[@BlackCatRedScarf]

I guess it is probably better to build something more efficient like an EZ Long to increase the range and flight time.

[@mm-hl7gh]

the drag gets more important on higher speeds.. maybe this plane is too slow to benefit from aerodynamic finetuning very much.

[@TheFightingFalconAce]

Even some footwell fairings would be huge in my opinion

[@josephv5484]

@@GRAHAMAUS that would require increasing the wing area so the wing can fly at a lower Coefficient of lift, or a different airfoil - reducing induced drag, thus increasing airspeed, or increasing airspeed by reducing parasite drag.

[@lasersaber]

Love it. I love flying my Sunny Motor with solar harvested energy. Free flying at its best.

[@NandR]

Still flying?

[@jackforster2691]

What is a sunny motor?

[@puggle3686]

Yay more plane content, keep up the good work!

[@Blaquer17]

That plane is PERFECT. It's for hanging out in the air alongside the paramotor guys. This is beyond my abilities, but it would be so cool to pal around with my friends' RC aircraft in the air from time to time.

[@TheDornado]

Maybe it was just the angle, but as a pilot that takeoff at 8:00 looked really close to a full on stall and then I saw the rudder kick and I am amazed it didn't snap/spin. Fly safe.

[@remee4685]

Yeah that was scary

[@laz272727]

Ultralights tend to have more engine power than a plane really needs, so they can do stupid takeoffs like these.

[@braeeee_]

as someone else said, ultralights usually have a surplus of engine power. his aircraft cruises only around 30 mph and has quite a high thrust to weight ratio so even though the takeoff may look silly compared to a traditional fixed wing small aircraft, for an ultralight it's pretty standard.

[@lr21643]

If full scale is anything like models, an aircraft with lots of dihedral will pitch down with a pure rudder input, in addition to banking. It's actually a good way to avoid a stall.

[@memeti5835]

You are best DIY channel in youtube 🔥🔥

[@jeffgrave]

I love how the critique idiots have no content on their channels. Peter, you are an amazing builder and inventor. Every plane you created is a masterpiece in design.

[@blue_beephang-glider5417]

You are good at building aircraft, and other things. I have thought of a flying project for many years, but work, family and lack of skill... The idea is an ultra safe, ultra light that can fit in a one car garage. Based on Chance Vought V-173 “Flying Pancake”. I feel this was a stall free low power high performing compact A/C dropped due to Jets... removable ailerons would fit it in a garage? By putting the pilot under wing for ease,stability and view.

[@bryanjones7347]

Nice BFL and plane my man! Good job

[@buzzypeterson1147]

By the way. The round tubes create a ton of drag, fairings man!

[@gotama570]

More than front window?

[@mgbrv8]

Do you think end caps on a wing with that much dihedral would be beneficial? If you could reduce the turbulence at the wingtips possibly you could get more flight time.

[@Pouncer9000]

With that much dihedral and that low of a wing loading you could argue the each wing panel _is_ a turbulence reducing device! Personally I'd lose the windscreen and sport goggles, should add a whole minute of flight time (also cheap and reversible)

[@zarrokea]

Wearing tight fitting clothes would be the easiest way to reduce drag, look at his pants wobbling around ! This already makes such a noticeable difference when riding a bicycle

[@Comandodadaaventura.8346]

O diedro elimina o uso de aileron. Aumenta a estabilidade.

[@borsfarago5874]

I got excited when he said it was under 254 pounds but realized he was talking about weight.

[@Rydog20]

Ur European💀💀💀🙏

[@gwheyduke]

Your aircraft are very useful. Each one is a valuable learning experience.

[@thomascarmichael6760]

Hey Peter, look at it in this way: you get to build flight time 20 minutes at a time. You also have the satisfaction in getting that time in a bird you built yourself! How cool is that!

[@katjoe1974]

“A fixed-pitch propeller. For non airplane people, that’s a propeller with a fixed pitch.”

[@vonanglin7468]

I enjoyed checking the plane out at the event. Bring it back next year!

[@lxaegg]

Id love to see you make a second set of wings for it with solar pannels, to lengthen flight time or even maintain the battery level at cruise speed.

[@Hellsong89]

Unless you are pretty much on surface of the sun there is no point doing that. You need the panels, those will increase weight and drag, nor wont be optimally angled to light. Then you need charger that also increases weight further. in the end you have increased weight so much that if motor is powerful enough to carry all that extra shit, you create about same amount electricity as it takes to carry extra weight. Only plus side would be potentially over time charging the damn thing if there is no power outlet around, but since range of this thing is so little already you can just land and plug it into wall charger...least long as the batteries are still alive, witch is maybe 10 years on high quality ones, before you need to replace them or just go up run out of battery in seconds and come back down. Note as airmanship you should always have extra fuel, if you need to go around or divert to other field. In this case you need extra capacity and since your life is essentially on the line of cheapest possibly made semiconductor actually working, i would highly suggest using two engine design with separate controllers, so you have back up system if main engine, battery or controller fails.. same with controls.

[@lr21643]

I don't think the surface of the sun is necessary. The atmosphere of Mercury might be good enough, but it turns out there are problems.....

[@lr21643]

Solar panels won't make much difference. Let's say you are flying an aircraft with 13 square meters of wing area at noon, on a perfectly clear day, when the sun is straight ovehead. Insolation might be about 500 Watts per square meter. If I'm not mistaken, that's about 6,500 Watts. You've installed very high grade, super duper solar panels which are 30 percent efficient. That takes you down to 1950 Watts. You've used a truly excellent motor that is 90 percent efficent, taking you down to 1,755 Watts (2.4 hp) or about the output of a hand pushed lawnmower that's badly out of tune. If you have a wonderful, large prop, spinning slowly, maybe it's 75 percent efficient at making thrust, so we're down to 1.8 hp. Let's say we have an ultralight that weighs only 400 lbs with the pilot, that has an L/D of 10. Both of these numbers are probably a little better than Mr. Sripol's aircraft. Let's say our aircraft gets it's best L/D at 50 feet per second, or about 34 mph. At 10:1, drag is 40 lbs. We have 40 lbs times 50 fps, or 2,000 ft-lbs of THRUST horsepower. That's about 3.6 hp. If we're using the aforementioned prop, we'll need about 4.8 shaft hp from the engine. To climb at a reasonable rate or take off in a reasonable distance, much more power would be required. To make the electric version work, even on a clear day at noon, on an equinox, at the equator, we'll need a Skycrane to hold a gigantic magnifying glass over our ultralight. In the real world, when the sun isn't straight overhead, or it's hazy, performance will be MUCH less, not only because of the less than perfect angle the light hits the solar panels at, but also because it's taken a longer path through the atmosphere, so more has been filtered out.

[@SnowingNapalm]

thanks for sharing your fun with us 💞

[@laprepper]

You continue to inspire me to build a plane. I’m very impressed with your work! Stay safe buddy. Maybe a few flights over the runway with new pitch choices to check amp draw prior to a full flight?

[@Maker238DeLoach]

Right. Rocket then plane. Already checked off pool. Make On my Friends.

[@thefrieber_362]

having that people environment is really cool, sunny warm weather, free space, custom builds

[@Danger_mouse]

Peter, it flys great looking at it 👌 I can't help thinking that you might save some drag (and Amp draw at cruise) if you put some simple cowlings around your feet 👍

[@armouredco6935]

If your projects bring you joy and a sense of achievement, it's not worthless at all, you have fun and you learn, all the people that say it's useless are just hating because it's easy to hate then to actually appreciate someone else's joy

[@chadsworth]

Definitely not useless! Always a complete joy to watch you fly man! See you at FF22??

[@chieffarkas]

Make it RC and bring it to Flitefest!

[@carnsoaks1]

The fuel count is about changing mass of the plane. For calculation purposes.

[@Dehakuzo]

That was my thought too, a battery is more akin to a gas tank, not the liquid in it. Battery doesn't get lighter as it's power is drained.

[@RCHobbyist463]

As someone learning aerospace engineering it is kind of interesting how we use Bregeuet equations to calculate range and endurance based on the idea that an aircraft loses weight during flight. I was never taught any equations for electric airplanes but it does seem like it would be simpler since mass is constant.

[@oldschoolmotorsickle]

Great video; I’d love to see more of this concept. The tandem in-flight footage is just about breathtaking. The delight of the flyers was evident.

[@Big_Penguin]

The scene where it was plane leading a 100 paragliders was epic. Like leading an aerial attack.

[@RTD_Fozzy]

I think you should try to upgrade that/your airplane to be solar powered, like figure out a way to attach solar panels to the airplane, but great video none the less 😁

[@ce152capt100]

Very cool video. The reason the FAA doesn’t consider a battery as fuel is because the battery loses very little (negligible) weight during consumption. However, aircraft burning liquid fuels lose considerable mass during flight as the fuel is consumed. Flight characteristics change considerably during flight as the aircraft loses weight.

[@DugzlasTV]

Nice!

[@PDWhite]

Sounds so good IRL. I love it!

[@mc-dev]

Be interesting to see flight time if you added batteries over the 254lbs mark

[@JSDFEnthusiast]

I feel like you can't call an aircraft useless because if it flies, or lifts off from the ground and returns to the ground in a safe manner, it's pretty much doing its job. And the fact that you're doing it with pretty easy to find materials makes them rather cost effective and material friendly aircraft which means they're pretty beneficial.

[@georgeishere69]

I think your projects are awesome Peter! I wish I could build myself a plane! Ps. around 9:30 you repeat about 15 seconds of audio

[@chrismineburg1163]

This is cool, like you I've been into rc for a very long time (30 years) and like you, I build my own piloted aircraft these days, I build paramotor frames and outside of training (5 flights) I've never flown a commercial frame. I'm at about 300 hrs flying paramotors and I absolutely love it but the gyrocopter bug is itching a lot. You're an inspiration bro.

[@pigeon4208]

If that had ailerons, I would want plans to build my own, seems like it flies smooth

[@boominS10]

I was thinking the same. Ailerons would help with stability.

[@brucepickess8097]

@@boominS10 Hi, to my knowledge ailerons do not aid flight stability as such. However the aircraft will be more stable as a result of flight control inputs placed upon it.

[@dancahill8555]

I think it's great!. When you get a fuel cell system you can set records flying around your patch!

[@beroth1]

I understand the reasoning for rudder-only control for turning, simplicity, lighter, etc. But what about x-wind takeoff and landing? Even if it's 5-7kts I'd imagine you'd still be crabbing a bit. Have you found that to be an issue at all? Also, coordinating turns is harder of course, but added dihedral you've got probably helps a bit.

[@ChevTecGroup]

I'm guessing that he avoids flying in those conditions.

[@shannonwhitaker9630]

Right you are: check this out ! m.kzbin.info/www/bejne/jWKueZ-Ejc93qpY

[@duskintheforest584]

Epic stunt! The fact that this aircraft is electric should be an eye opener for the doubters of electric car technology. Peter Sripol you serve a purpose with your builds: proving it can be done! Plus I'm sure it's a gas to actually fly something you built

[@wflagg]

no such thing as a useless project, you can always at least learn something from them.

[@kketelhu]

This is probably one of the coolest planes I’ve ever seen! If you added floats this thing would be even cooler. Good job and continue being awesome

[@GeneralPadron]

As I have commented before, they make extremely light weight and flexible solar panels. Those would work perfectly for your wings on this current design.

[@firstletterofthealphabet7308]

the one concern I have about that is that flexible panels usually have much less wattage than most rigid ones.

[@petevenuti7355]

​@@firstletterofthealphabet7308 yeah but they work in indirect light and cloudy days better

[@skipbisby7307]

Peter, i wish i had half of your talent when i was a young man. You have what it takes to make a difference in the world. GO FOR IT!!

[@Guihcouto]

Awesome as always! It would be amazing to see you building a glider. That would allow you to fly longer, and using your electric motor you could also self launch. 👏🏼

[@youknoweverything7643]

You are crazzy for flying a home built plane love it. You just proved that anyone can build a electric ultra light for fraction of cost using simple materials

[@elejercitodesalto7856]

No hablo inglés pero ese avión evoluciono bastante yo ví la primera versión volar en 2017

[@buddyl962]

Not useless at all! He is becoming a rather fine pilot, and a terrific engineer!

[@MX304]

8:07 that was sketchy. Is it still a bit tail heavy?

[@shannonwhitaker9630]

I believe the trim tab indicates it’s nose heavy possibly.

[@artamereenshort6610]

Love your video...and thinking about "Solar Impulse" ( Swiss solar flight) when i'm see the title. Putt on a plastic film, only sollar sells like : Size: 166mm × 166mm , Thickness: 0.190mm. It's a lot of soldering work, but the gain in weight is huge.

[@jkangaroo]

Curious if flexible solar panels added to the wings would make a useful difference in flight time? Or would their weight push it over the limit?

[@Billo-07]

Watch rctestflight, he's done a RC solar plane before.

[@Ritefita]

yes, they would make enough for the calmest cruise.. yes, they definitely would push the weight over any limits.

[@jasonsinclair6949]

I hope he adds the solar panels on the plane in a future video.

[@jasonhowell7763]

This isn't useless, it's badass, and it's the future of aviation.

[@SpartRyan]

Your creations are useful, interesting, and fun. What more can we ask for as your audience? Thank you for all your videos :)

[@eekee6034]

Tucking your trousers into your socks will give you more flight time. I'm not sure how much more, but my experience with bicycles is that when it comes to air resistance, flapping clothing is the ultimate evil! ;) Just tucking stuff in to stop it flapping made a huge difference.

[@youthinkitwemakeit9084]

Yeet

[@MrPinguinzz]

3:55 this legs outside the frame design looks like a huge drag penalty for no reason, a simple cover would probably make a huge difference

[@MerlooV]

Peter, i have a request why dontvu make your own jet powered plane!!

[@mattivirta]

RC planes have lot many jet engine if build this plane or new plane whit 2 or 4 jet engine has perfect and all interest.

[@MerlooV]

@@mattivirta correct

[@kbjerke]

That little airplane looks like a *TON* of fun to fly! Just the type of vehicle I'd like, to fly around the pattern a few times at the local ultralight park, and "keep my hand in it." As a retired senior, I can't see myself getting into private aviation in a big way, but your invention would certainly fill the bill! Thanks for sharing, Peter!

[@Authmion]

With a couple of hours on the plane, would you consider releasing plans for it? or maybe after improvements have been made?

[@bradleywhais7779]

That is a really bad idea

[@Authmion]

@@bradleywhais7779 why's that? There are plenty of plans built ultralights out there

[@Theorex]

Your videos are the most comprehensive and only entertaining ones on ultralight construction on the platform. They have been the one thing keeping me sure I can build my own plane here soon.

[@fractal4284]

You should make your entire wing a solar panel array do you think it would keep up with the amount of power that single engine is using?

[@eastoforion]

no lol true solar planes are very difficult to make

[@AlRoderick]

It makes sense that the FAA would include batteries as dry weight, they don't get lighter as they discharge. What the FAA is concerned about primarily is landing weight, or more bluntly how much collateral damage you'll do when you crash. If you're expected to land with it, it counts.

[@myentertainment55]

Short question : do you ship them in parts to customers to save shipping fee and do you need some kind of license or permissions to operate?

[@josephbarnes7217]

She’s a pretty plane. Love watching you build planes

[@melcrose]

Ask "bruno" (glider flying blog) about "trying stunts" without full OK / training / certificates to do so. He lost his ticket for 6 months.

[@FMJR25]

Nice BFL! 😉I knew there was a reason I liked you other than for your entertaining videos.

[@cmayrc]

Great video Peter, keep up the awesome work! Your airplanes and videos are definitely NOT useless!!!

[@xXRedTheDragonXx]

Peter I just wanted to say, your videos have absolutely inspired me to create. Not airplanes, but just anything that I want! Since seeing you be so successful in everything that you do, I have started to build things that I have never thought I was able to do. I have learned circuit design, learned how to actually operate a 3D printer, and learned some of the basic principles of aerodynamics so I can start building custom drone parts to start building my own quadcopters and model airplanes. Please, keep doing everything that you're doing and most importantly keep making videos about your projects! I love seeing what other people online create because it gives me inspiration to actually work on my own projects, no matter what they might be!

[@lr21643]

Judging by the successful quad copters I've seen, knowledge of aerodynamics isn't required. I think they fly because they're so ugly the Earth rejects them, just as with helicopters, only more so. ;-p

[@diyfireking]

The feeling of flying in the sky is great. 🐱‍🏍🐱‍🏍🐱‍🏍🐱‍🏍

[@Wrublos212]

For me such classy, simple looking airplane is an essence of flight. Useless project ? Its not mail delivery airplane, Its machine for enjoying every second in the air. It looks beautifully when its airborne.

[@leeudraak]

I love that 'retro-style' power box in the trailer! 😃

[@silvesby]

I love that bicycle analogy. And of course, the whole video in general!

[@RealAndySkibba]

Super cool project!

[@PyraMink]

*And the Sripol plane saga resumes it journey*

[@Zero.0ne.]

Spectacular invention!

[@plywoodcarjohnson5412]

Great!!! I think you should do precison melon dropping from this aeroplane.

[@thetwogardens6048]

This guy is a real Adventurer !

[@historysattic9112]

Go Peter! Keep reaching for the stars!

[@thepatrioticgamer3101]

One way you could extend your range is adding a propane fueled generator to charge the batteries in flight, they make generators that produce 6k watts and can power an rv for up to 12 hours, and I'm thinking about building an airplane that's hybrid electric, for longer range.

[@jesseh9523]

at that point you might as well just put a combustion engine on it.

[@Cardstacker]

I really like that plane because its basically a giant Big Red Slow Stick which is all I've ever flown.

[@xplanation2263]

Just moved to Dayton Ohio been on the lookout for you flying high! Love your enthusiasm and willingness to try and learn from it. We all need to be more ingenuitive

[@MasboyRC]

Amazing project 👍

[@kman009]

This is very nice, here is a challenge for you and a fun idea, build a slighter bigger one, maybe tow engines/propellers big enough to carry at least 3-4 people and take some other people up with you, at least 3 maybe one next to you and one in the back.

[@gscindian5284]

Dude!!! This is awesome!!! I hope you still flying it!

[@Chris.BootsontheGround]

Excellent built🤙🏼, flys high & fast enough, lands well, what more can you ask🤷🏼‍♂️. Keep up the good work 💪🏼👌🏼

[@nightelfmohawk9821]

Man Peter your engineering skills are truly admirable, I remember the good old flite test days making hilarious contraptions for the RC world that was always a blast and now youve scaled up to full size it's so great to watch you do these things. keep on being awesome!

[@therandomcoder2200]

Yay love when you post videos.