Right from Scratch DIY

Have you priced the fuel cell yet? Once you’ve forked out the cash for a fuel cell (I’m guessing it’ll run you about 5k), maybe you can buy an H2 generator (I saw one on ebay for $700). You could ship it ahead of you, and have a fill-up base station when you get there. Could probably sell it before you leave if you wanted to save the $$ and hassle of shipping it back.
An empty tank of O2 is just a tank. If it’s a SCUBA tank in the US, the valve has to be off and a SCUBA shop has to inspect it and say there’s no pressurized gas… which is a gimmick, because the valve being off means there’s no pressurized gas of course.
I’ve looked into H2 cells in the past, and there was never anything viable… I’ll be interested to follow your progress if you go this route.
Where did you come up with your energy information btw?.. didn’t see anything that specific in a search.
LOL, I spent a lot of time trying to figure out how your calculation worked… but after a good deal of research, I think you mistyped “80 hours flight time” when you meant “80 minutes flight time” :slight_smile:
Does the aerostak 500 carry twice the H2/Wh do you know? As a 300lbs guy who really wants an EPPG, this may well be worth the $$ to me.

I’ve looked in to this a bit more (only like 10-15 hours of digging and reading ;-). (Edited after I found more info)
With tank and battery cell, I think you’re looking at under 10lbs total “battery weight”, but once you commit the 5lbs battery cell, you can expand the amount of gas stored for very little extra weight. Unfortunately, refilling takes special equipment which is quite heavy making it unsuitable for ever being able to charge between flights with current tech. With h2 generator, compressor, fittings, and the tanks and battery cell, total cost will likely be over 5x the cost in equivalent LiPo and gear.

If you spring for it, if you want to fly 80 minutes while drawing 80% of your 300W available wattage, you would be looking at about 2.4L/min (Based off listed 3.4L/min max and adjusted for reduced pressure) for a total of 192L of fuel needed… if you filled the 2L tank to 300 bar for a total of 600L of H2 at 1 atm, you should get just shy of 3 hours of flight I believe.
If you did 20L of H2 at 300 Bar, that’d be 6000L (Right?.. been a bit, maybe I’m forgetting something), giving you 41 hours of flight time… make a good fill tank for a trip! (Hopefully resupplied from a solar powered generator :wink:

If you had 2 2L tanks, 1 tank 1/3 full and the other 2/3 full, you could fly off the first, come back and connect the two tanks (assuming you have the appropriate adapters) to make both tanks 1/3 full. You then can launch 2 more flights that day before you have to call it :slight_smile:

(edited to remove specific pricing upon request of HES)
I heard back from HES regarding the practicality of a hydrogen fuel cell. Looks like it costs about three times as much as I was estimating, and I estimated it cost like 5 times more than batteries, however, HES asked that I not include pricing information in the post…
I’m hoping in a couple years prices come down, and hydrogen production products become more streamlined / affordable… sure would be neat to fly with 6 hours of fuel if I wanted to without any notable additional weight :slight_smile:

It’s my dream to fly with hydrogen. $15k and I’m up in the air or is there other parts involved? I’d add a trike and a delta wing and have a mini airplane for $26k

I noticed the a-2000 is only rated for 2kw. I thought this system used much more than that to even achieve level flight. I’m very interested in flying with hydrogen. If more money goes into these companies other companies will shift their focus to make hydrogen too. This will help get cost down and keep it there.

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That would be for the “battery”, you then need the motor and all the rest of it, but it could work with any EPPG design, so another $5k or so and you just need your wing. You also need somewhere to get H2 from, and if you’re making the H2, you have to compress it to 300 bar (or whatever you choose to pressurize it to). I’m not sure if that price includes the carbon fiber tanks or not.
I think you’re right about Watt requirements… (I think I had assumed the original post about the aerostak had sized it correctly)
GliderPilot provided some great per-motor ‘live’ data on this (thank you sir!), so we know what we’re working with… according to his setup, level flight draws about 1500Wh(x4), while full throttle draws between 3000-4500Wh(x4).
So, you can install eight 2000W fuel cells, and your dream has been accomplished! Throw in the 9L(x4) carbon fiber tank, and for only 100lbs of “batteries”, you can get 50-60 minutes of flight! :wink: On the plus side, each additional 9L tank only weights 1/2 lb, and the h2 itself weighs a bit less than that, so you could expand this to much higher capacity for very little weight difference. (And anyone who sees you fly by will think you’re a para-bomber)

I feel very much the same way about H2… it’s been a dream of mine for some time… particularly human/alternate powered transpo with H2. The prices here have a great deal of opportunity to drop if interest in H2 can be furthered.

Move to Japan – they are looking long term and changing whole infrastructure to Hydrogen with Toyota behind them.

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Already half way there, I live I in Hawaii :slight_smile: hydrogen is the most abundant element in the universe. It’s actually number 1 on my table.


Which Island Bodeway? I’m on Big Island in South Kona. Would be fun to find someone else to fly an EPPG with :wink:

Oahu. I want to get a delta wing and load it up with batteries for inter island flights. The longest distance between islands coast to coast is 63 miles the rest are below 26.

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If you want to fly so far over open water i think a deltawig even with 1 gasengine would be a stunt!

Even a 1 engine airplaneplane would be a high risk!

With elektromotors it seems not possible to me.

Just think what will happen if the 1 engine fails…

Not many chances to survive that adventure in such a case in my opinion.

Sorry for not so romantc fiew to that scenario…

All the best

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I’ve thought about this as well… it would be hard to manage it without it being super high risk though. (Unless you have a safety boat in your pocket) Even assuming landing in the water isn’t a risk, I’ve heard sketchy things about what the winds do between islands, and I would want spend a long time looking at the winds at various elevations before actually getting too far out.
I have thought about mounting to a canoe or other small watercraft so that I could make a water landing if I needed to… unless I figured out something incredibly ingenious with the wing though, I probably wouldn’t be re-launching. So long as the motor is saltwater proof though, you could still motor your way to shore.

I agree, but I am curious why you think an electric paramotor is notably more risk than a gas solution? Are you expecting a higher rate of failure, or are you thinking about battery life, or just scary things the wing can do in unknown/variable wind conditions, or…?

the motors could be isolated which would make this safer than any single prop plane in terms of a motor out. Some of the islands have ripping Venturi effect between them. I skydove in the windiest place in all the islands and the winds were rarely under 30mph past 8am. This would need to be done just before sunrise, and with flares and a little inflatable raft. I’d just get stuff that I could bail out with and use a round into the water if something went wrong. The gear is gone in the event of a water landing. A heli won’t cherry pick the rig I don’t think. But with proper safety equipment a rescue is possible. Boats have radios designed for this sort of thing. I think it would be best to call the coast guard and give them a heads up. But I don’t see why not. With everything designed specifically for this I’d say it’s way safer than any single prop engine. That is IF an engine out could still get you there with isolated motors/batteries.

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@fredrick 00
With a gas engine you can fly 2,5 to 3 hours with elektric 45 to 60 minutes.

If your energy is used you will have to land .

There will be no upwinds and not much thermal action over water.

There are trade winds in your aerea as well and high waves…

There are some things to avoid when flying…

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Makes sense to me, and on a well designed and tested system which has a water sealed electrical system (to prevent salt water corrosion), my limited knowledge on the topics involved agrees… If you could wrangle a support team up, you could have contacts on your departing and arriving islands set to contact rescue services if you lose contact for a specified amount of time. (Which wouldn’t be very long)… I think you’d want an EPIRB with you as a raft between the islands is a pretty small target, but at that range, an EPIRB would probably be pretty effective. I’d also let the coast guard know as you mentioned.
With our current technology, you could even have people e-monitor you where you have cellular reception. I know between Big Island and Maui, there’s only a very short span where cellular cuts out at higher altitudes, but seems to remain functional at about 50’. (Per watching a guy fly his 4G drone over)
If you put together all the equipment for it, you should swing by one of the outrigger canoe clubs, and see if they’re interested in doing an inter-island voyage to coincide with your flight… then they could act as a safety boat for you, you could spot for them, and you could both get a lot of publicity by filming from air and water. Would want to wait until they were 1/3 of the way between islands or so to take off I would expect… depending on currents, winds at cruising altitude and all of course… but could be a fun PR stunt.
If you really have a sizeable budget, the SS/Li hybrid batteries might be something worthwhile to you. They advertise over twice the energy density of standard LiPo batteries, and are primarily manufactured using existing lithium battery production facilities making the price very possibly reasonable.
Not nearly as cool as Hydrogen… Lithium is toxic with a horrible mining process, and human rights violations associated with it’s mining… but the only H2 solution which seems remotely economical at this time would be a combustion engine… maybe a series of jets like the ones the jetpack guys use. The fuel could be renewable sourced which would be great, and with a bunch of carbon fiber canisters, and H2 weighing virtually nothing, you could carry almost unlimited fuel… without proper planning you would burn lines in a heartbeat, but the reduced intake/exhaust surface area might make it overall safer than a standard rotor setup.
(EDIT: my mistake; you can supplement the gas easily… a full conversion is trickier.) You can also convert a gas engine to run directly off H2 with very little modification. If you pump H2 in the air intake, it should run without gas supplied in most, if not all, instances. I’d want a pretty solid mechanic to listen to and play with the engine for a bit before I’d trust it… but gasoline is low in oil, so my main concern would be that the mix be correct so you don’t blow your engine up. H2 combustion engines are notably safer than gas engines too… no residual fuel to keep a fire going after any initial problem, and H2 will generally blow out it’s own fire.
You wouldn’t get the “silent” glide… but you could put an electric start on it, and still be much lighter than a standard petrol setup. Even without electric start, I would expect H2 to start far easier due to the dispersion/surface area of the explosive element making every combustion a complete combustion. Being an H2 buff, you probably already read about gas having an energy density of only 45MJ/Kg whereas H2 is 120-140MJ/Kg, making the cylinder you store it in the only real weight to consider. Gasoline engines have a thermal efficiency of less than 40% (generally less than 30%), so that’s about 14MJ/Kg for gas… H2 would probably be a bit more efficient, but still similar for about 40MJ/Kg.
(Assuming I made no errors)
Electric’s a bit different, but if my calculations are correct, I’m seeing LiPo as having an energy density of about 0.7. (192W/kg based off the weight and capacity of the Bonka)
I’ve been thinking about rigging a paraglider to a recumbent bicycle so I can para/bike/camp my way up through indonesia for a journey hopefully ending in Tibet, to continue to Jerusalem if I felt up for it still (Following a historical martial arts path)… that would be a while down the road for me yet, as once I have a rig that could be capable, I’ll have to devise how to make it practical. My current plan is to hire boats or airlines to get across the major water stretches… but I have been thinking about if I could make the recumbent water proof, and extremely buoyant, landing in the water in and of itself might not be a deal breaker for me. Wing’d be done at that point though… though I could rig it as a sail and it’d dry out if I could figure out counter-ballast… if I were an anime character, I’d just go into submarine mode at that point though.

Gotcha. Makes sense… Yeah, the fuel issue will definitely need to be resolved… For something like that, I’d want to end my flight with at least 1/3 of my fuel remaining, and during the crossing (particularly into a headwind), constantly be evaluating if the fuel last as expected, and where my point of no return is. If you do those things, however, the fuel supply issue is really just a matter of carrying enough fuel… which may not be reasonable with LiPo, but that’s another topic :wink:
Trade winds are consistent winds from a given direction… would that not be an advantage? If he goes from Oahu to Big Island, it would be a bit of a headwind from the left side which may not be ideal, but with enough fuel it’s easy to adjust right? Trade winds are usually about 15MPH, rarely higher, though what they do as they whip around the islands is another matter.
High waves I would only see as a concern if you had to make a water landing, and then, their primary issue is if there are also high winds, or just because they make it harder for the coast guard to find you when you’re in the trough. In high winds, they’d be breakers and would make life on the raft waiting for the coast guard pretty lively… but I don’t think you’d want to make the crossings during high winds anyway, and the weather systems in Hawaii are fairly predictable. (We either see it coming across the ocean, or it’s a localized system)
The other things are always a very real concern… I don’t think anyone could do this crossing without a thorough emergency backup plan and be remotely safe… as it is, Hawaiian residents tend to be a bit more willing to risk their lives than mainlanders… so long as a person is fully aware of and understands the risk and prepares as best they can, however, it tends to work out for the best.
I know a number of people who have kayaked from Big Island to Maui in plastic kayaks with plastic pins holding part of it together… I think the risk factor is fairly comparable, particularly if he has redundant propulsion, and coordinates and prepares as he mentioned.
I think it’d definitely be a feat… I’d watch at least an hour of it on youtube for sure :wink:

@fredrick 00
1.) Great idea to travel with the paramotor
Becouse especial the open ppg is very light and transportable.
The downside here ist that there is no cance to transport bonka litium batteries in any plane. You can search here the comments many users have made.

  1. Please read :

My opinion: when you land in water more than 1 meter deep you will die.

Even if exact where you hit the ocean are some divers to cut your lines and give you air to breath i would not bet that you survive.

Becouse all your gear is pulling you down in the same second like you have stones mounted on you, all the lines can easily be in the way, all the canopywhich is airtight and prevent you from seeing something and breathing.

I think when you are not able to jump from your equipment to be free bevore you hit the ocean there is no chance at all to survive longer than you can hold your breath.

And if your batterie gets a little defect at your crash you have all the selfignitionproblems of this batteries they could burn underwater while sinking and selfignighting one after another…

So all your safetyequipment will sink or burn or be in the way to free yourself from the sinking stuff and lines.

Cant imagine how anyone would safely survive under any circumstances the first 6 minutes after watercontact.

All the best

Flotation devices for both yourself and motor might buy you enough time to cut your gear free and survive until you die of exposure or are rescued. SIV courses happen over water and people pull reserve and hit the water when the inevitable happens. There are boats standing by so it’s just a learning moment not the end.

@grejen 711
Siv trainings are mostly or always without ppg motors as they would be damaged when they get under water, not sure if any trainer would like to be responsible and allow you to use a litium powered ppg in his course where it is expected to land in the water if something does not work.
Often people test there rescuecanopy in such a course to simulate what it will feel to have 2 canopies open at 1 time.
A flotationdevice for the motor and batterysystem is hard to install in a way that the on the back mounted motor and the heavy batteries does not float over you and does turn you face down all the time.If you lie on the water you will float - think about the weight of 2, 4 or normaly 6 bonkas, they will not float at all.
When you mount 1 device to the motor and a seperat one to you expect that you will sink about 1 sec. Like a stone bevore they fire and than you will go up quick direct into all lines and 50 m2 of glider and parachute with no rescue teams waiting for you on the ocean.Not to forget having maybe an already underwaterburning battery mounted on your back at that moment.Even if you invent a way that you and your motor are floating face up in all circumstances you will float direct under 1 or 2 canopies which also will not help to survive longer than you can hold your breath even in a bestcasesecenario with no wind no waves and rescueboats and divers being prepared.I think if you plan to jump with your car from a driving ferry into the ocean and plan how to survive that stunt becouse you call the coastguard before you start your car is more save than those scenarios.

Why couldn’t you just bail out with a round parachute and all safety equipment strapped to your chest/lap in the event of a unavoidable water landing? It’s like any other flight, plan for the worst case. If anyone died because of a water landing it’s not because they flew over water. It’s because they weren’t prepared for the worst case scenario.