So I've been building an ultralight

[pbj]

You’re spending an awful lot of time trying to convince us this isn’t dangerous.

Wheels left the ground yet?

[danny_galaga]

You’re spending an awful lot of time trying to convince us this isn’t dangerous.

Wheels left the ground yet?

Yes. One at a time- I had to replace some parts in the undercarriage already 😄

[danny_galaga]

Most important part went on yesterday - a cartoon of its pilot as Axel

[danny_galaga]

Well, it's down to paperwork now. Weight and balance logging is the next step.

I now haven't flown for 7 months in anything, and a number of YEARS in a tail dragger, so I'm going to do a refresher course. Not cheap of course...

[pbj]

[danny_galaga]

GERRY DOWN!

[danny_galaga]

This is what $900 of weighing looks like

[bobbyb13]

I like the technique here!
What was the final number?

[RandyT]

This is what $900 of weighing looks like

I would have been tempted to find the center of balance and put a bottle jack on a scale

[danny_galaga]

This is what $900 of weighing looks like

I would have been tempted to find the center of balance and put a bottle jack on a scale

😄

There's a standard procedure for all this. You start with a datum point and then measure back from there..in this case  it's 100mm out from the wing strut attachment, plumb bob down to the ground. With the correct info, you can plug in the weights for each flight, in my case it would normally be pilot/passenger, how much fuel and two different luggage locations. Then you can see if it sits within the flight envelope. There can be situations where it's within the envelope when taking off, but if the fuel is nearly empty, it will be out of balance.

Now imagine how complicated that is for a jet airliner!  I'm going to bet that whenever you have whole rugby teams etc in board, they'll be in the front 😃

[RandyT]

That's why I don't fly.  I'm lucky if I take a minute to kick the tires on my vehicle before piling in and driving off. 

But on the large jet airliners, I get the feeling that the engines are so powerful and the passengers/cargo make up such a small percentage of the overall weight distribution, it only becomes an issue if they get overloaded.  I could be wrong, but I have never seen passengers moved around on a half-booked flight or the luggage guys do anything other than just toss the baggage into the hull of the craft "willy-nilly".

[danny_galaga]

The further away from the centre of gravity, the more effect it will have. Trust me, you may never see them ever have to move people around, but they have to do those calculations by law. If you think about it, 100 passengers is maybe 8000kg. That's not insignificant.. pretty much any wing stalls at about 14° angle of attack. If that's exceeded it doesn't matter how powerful the engine is, you've stalled. And if you are tail heavy, you may not have enough elevator to unstall it. In fact being tail heavy probably caused the stall in the first place.
Here's the basics of what happens with weight and balance

https://aerocorner.com/blog/aircraft-weight-and-balance/

https://youtube.com/shorts/nkYgznZLgyo?si=VvVBVoSdhWv6SpX3

[RandyT]

The further away from the centre of gravity, the more effect it will have. Trust me, you may never see them ever have to move people around, but they have to do those calculations by law. If you think about it, 100 passengers is maybe 8000kg. That's not insignificant.. pretty much any wing stalls at about 14° angle of attack. If that's exceeded it doesn't matter how powerful the engine is, you've stalled. And if you are tail heavy, you may not have enough elevator to unstall it. In fact being tail heavy probably caused the stall in the first place.
Here's the basics of what happens with weight and balance

https://aerocorner.com/blog/aircraft-weight-and-balance/

https://youtube.com/shorts/nkYgznZLgyo?si=VvVBVoSdhWv6SpX3

I think the thing that makes commercial airlines a bit more forgiving is that the wings (and engines) are pretty much centered with the cargo.  I'm not sure it's possible for the positioning of people to throw that off beyond what the flaps, etc. are rated for, unless for some reason 1st class and half of coach is empty and everyone else is sitting together.  But on the luggage side of things, I can see them weighing the carts full of luggage, and doing their best to distribute that as evenly as possible in multiple holds.

But like you said, in the case of a rugby team, they would flock together.  Everyone else would find a new seat and naturally disperse if allowed to (from personal experience.)  Although, I'm not sure that is permitted anymore.

On the flip side, I wonder how all of that changes when the craft is empty.  I know they are loathe to move them in that state, but I imagine it must be done on occasion.

[pbj]

Yeah, I’ve been asked to move before for weight distribution.  Can’t recall having to do it on anything like a 737, but it’s happened several times on smaller ones.  Hooray obesity.

[danny_galaga]

As long as you are under 160, we can fly in my plane 🙂Although at 160, I do t think we can carry any fuel...

[pbj]

So, it turns out the US Postal Service has a museum.  It’s actually fairly interesting and apparently nobody goes to it.  It is also impossible to buy stamps or mail anything there on Sundays - they sent me across the street to Walgreens.  I think if there’s one place in the world that you’d at least have a stamp machine and a Mail Drop is the US Postal Service museum but apparently not.

Anyway, TL:DR - saw these, thought of you

 

[danny_galaga]

I have a pair of cheap retro flying goggles. I bought it to ride in The Distinguished Gentleman's Ride one year. I think I might wear them in my plane. Thanks for the idea 🙂

[danny_galaga]

Ghetto jack ftw

[pbj]

I got in a hot air balloon last weekend.  Pure, unadulterated terror.  Godspeed, Danny.

[nipsmg]

I just got my PPL recently and have been toying with building an ultralight-- then completely scrapped the idea because I'm an idiot who takes on too many projects but never finishes any of them.

This looks spectacular!  What did you end up with as useful load after the W&B?   And did you go with the 912?  And are you PPL or sport pilot? Are you even in the US? so many questions.

[danny_galaga]

so many questions.

😄

I got my ppl in the 90's and then let it go. About 6 years ago I converted it to what I guess you call a sports licence. I'm in Australia.

I've regretted starting this almost from the beginning. If you start too many projects, which I do, then starting this sort of project may kill you psychologically. It has me.

But some tips if you are think about it:


Don't believe the manufacturers BS - they will say you can build it in six weeks and that there's nothing extra you need to get. They all say this. And all kits have things missing or wrong or both in my case. Even as it was at sea on the way to me, they issued an AD on it! They were grounded for a short while in the US I believe. So once I got it I had to build it knowing that the whole empennage would have to be replaced. The updated parts took over a year to be produce. I actually had to replace a lot of the rear end of the fuselage. But you couldn't really know until you got to that point. Very, very unsatisfying having to pull apart what you've only just built. Then there's all the missing/incorrect parts you come across as you're building.

I get disappointed easily. This has been the most unfun thing I've ever done.but it's way too expensive to ditch like you could with a mame cab that didn't quite work out.

Don't get me wrong, it's not something I DONT recommend doing. But if you have traits not dissimilar to mine, think twice.

Think- if there are hurdles like that, do I have the personality to rise to the occasion and get on with, never looking back. Think about other projects you've done that you have unfinished and why.

All kit manufacturers act like it's a box of Lego with everything there and perfectly designed. If you have a strong personality, and ignore the BS, knowing there are going to be exasperating moments then you'll probably be fine.

Me, around the time I bought the kit, I was toying with buying a T bucket or similar. I would have had MUCH more fun in those years I've been building this thing.

Anyway, the most joy I get with this kit now is complaining about it 😄

There's about 240kg total usable load.

Oh and the kit manufacturer? They've gone broke ..

[RandyT]

All kit manufacturers act like it's a box of Lego with everything there and perfectly designed. If you have a strong personality, and ignore the BS, knowing there are going to be exasperating moments then you'll probably be fine.

Sounds like every Chinese scooter/ATV (and quite a number of other things from that corner of the world) I have ever purchased.  But it usually ends up ok at the end...usually.

[danny_galaga]

All kit manufacturers act like it's a box of Lego with everything there and perfectly designed. If you have a strong personality, and ignore the BS, knowing there are going to be exasperating moments then you'll probably be fine.

Sounds like every Chinese scooter/ATV (and quite a number of other things from that corner of the world) I have ever purchased.  But it usually ends up ok at the end...usually.

😄

There were actually two kit manufacturers (out of hundreds) that were 100% complete for EVERY kit .the first was the Christensen Eagle. Pretty much the father of the modern kit. The other was the Quicksilver MX. They both utilised a simple fool proof system. It's boggling that no one else seems to use it. Basically you would have sheets of cardboard printed with everything single part shadowed and described. Now you have a guy place all those parts on the shadow. Then he covers it in heat seal vacuum clear plastic. Very very easy to see something is amiss. For instance a missing part would stand out. Also say a bolt that is too long or short will stand out. The person packing those sheets just has to go off a checklist but if they are just numbered say 1-50 you don't even need that.

As you build your plane, only when the manual asks for it, you cut the part out with a single edged razor. Maybe factories don't do it now because it might take up more space. But where's the savings if you have to keep sending parts out to your increasingly irate customer? I reckon my guys spent over $1000 on DHL freight sending me missing parts. Right at the beginning, the engine mount had some corrosion on it. Something went wrong with the plating process. So they sent me another mount IN A CARDBOARD BOX!  Yep, when I got it, it was bent. So then they had to send me another, this time in a small wooden crate

[danny_galaga]

The only two manufacturers in mind that could guarantee a quality product were at extreme ends of the scale. The Eagle was a fully aerobatic plane powered by usually a Continental 0360. About 200hp. The MX was an early ultralight powered by something like a 30hp single cylinder two stroke.

[nitrogen_widget]

As long as you are under 160, we can fly in my plane 🙂Although at 160, I do t think we can carry any fuel...

KG's or LB's?

[bobbyb13]

That Eagle is one badass looking machine!

Everybody can keep the gocarts with wings that look like kites I used to fly as a kid.

[danny_galaga]

As long as you are under 160, we can fly in my plane 🙂Although at 160, I do t think we can carry any fuel...

TV
KG's or LB's?

KG's. Lbs is from the olden days. We are now in the future 🙂

[danny_galaga]

That Eagle is one badass looking machine!

Everybody can keep the gocarts with wings that look like kites I used to fly as a kid.

Fantastic isn't it? It's not for beginners though. You need to have an aerobatic endorsement ideally to fly this, and be proficient. And it's probably thousands of hours to build, as opposed to probably less than 100 for the Quicksilver.

[pbj]

How about a gokart with a parachute and fan?

https://www.easyflight.com/

You could have been in the air five years ago with one of these.

[danny_galaga]

How about a gokart with a parachute and fan?

https://www.easyflight.com/

You could have been in the air five years ago with one of these.

I know, dammit. One time I was flying over a lake and saw one just pootling along a few hundred feet above the trees. And I thought 'now THAT'S flying'. And if something goes wrong, you've already got a parachute 😃

Mind you, you are very limited in what you can do. Same with the Quicksilver. Best for crack of dawn, or late afternoon when the air is more likely to be calm. And no passenger.

[bobbyb13]

Looks like there are two person versions of those powered parachutes to be had for $50k.
Could be really fun in the right place/time.

[danny_galaga]

Looks like there are two person versions of those powered parachutes to be had for $50k.
Could be really fun in the right place/time.

😲

50k USD is probably about what I've spent on a real airplane. Seems to me theyve missed the point of what a powered parachute should be about

[bobbyb13]

It is impressive that you have only spent that much to be able to build such a cool machine.

I would think that for group float activity ballooning would be far more fun than dangling from a parachute with somebody..