Took my bike for a short flight!
Posted by _jame5_@reddit | aviation | View on Reddit | 125 comments
This was the 4th takeoff and third successful landing of AeroLazarus, built by Southampton University Human Powered Aircraft.
The aircraft weighs about 37Kg (minus engine/pilot), flies at about 18 knots, and requires about 400w (0.5 HP) to fly in its current configuration. To keep weight down it has no ailerons, which combined with the low wing loading makes handling, interesting, in any crosswind or gusts above 2 to 3 Kn.
Possible-Armadillo68@reddit
Does it have gears? Internal gear hub or derailleur? If so, how many gears? And what size chainring and cassette?
falconbrad@reddit
Not to diminish the achievements of this team, which are impressive, but there is https://en.wikipedia.org/wiki/MacCready_Gossamer_Condor and https://en.wikipedia.org/wiki/MacCready_Gossamer_Albatross
xixtoo@reddit
Still in ground effect though
a_scientific_force@reddit
Now you need to get out of ground effect.
SeaMareOcean@reddit
Honestly is that even possible? I don’t think I’ve ever seen an human-powered aircraft operate out of ground effect. Even the Gossamer Albatross crossed the English Channel at around 5 feet of altitude.
_jame5_@reddit (OP)
It's probably possible, but its just further to fall if things go wrong (the pilot doesn't have a seat belt/harness).
We also don't think ground effect has a significant effect - we've got such a short chord, as well flying so slow and our wing loading is so small that there isn't much of a high pressure bubble to provide any lift.
Bombadilo_drives@reddit
I'm probably naive on the topic, but would taller gearing/more gears help? Seems like you could really get that prop moving with just... more gears
ReallyBigDeal@reddit
Faster spinning prop isn’t always better.
SeaMareOcean@reddit
Good points, thanks for the insight. And congratulations, that was a lovely flight in a beautifully engineered aircraft.
_jame5_@reddit (OP)
Thank you!
gowerskee@reddit
400W is significant!
_jame5_@reddit (OP)
Luckily due to the runway slope I was only putting out around 300w, and we think we can get rid of another 50w with some drive train improvements
Osmirl@reddit
Lol so that thing can basically fly with an ebike drive train.
My E-MBT has like 650w peak and 300w sustained even with a small 400wh battery thats an hour of flight time lol
_jame5_@reddit (OP)
It's ridiculous how bad humans are as a power source compared to electric motors - all the engineering we do is just compensating for the terrible engine
GretaTs_rage_money@reddit
I once saw a video that explained this when talking about mobility: "you can't get much more efficient than a vegan on an ebike". 😁
The CO2e resulting from the additional food needed to ride a normal bike is greater than the total CO2e of the electricity, although that might be for renewables.
Osmirl@reddit
So me lol 😂
bendallf@reddit
Don’t want to sound dumb at all but have you considered using an electric bike? It seems it would give you more power than peddling alone? Thanks.
_jame5_@reddit (OP)
You could, but it completely undermines the whole philosophy of the aircraft. Everything is designed around being power limited to an extreme extent, if you add an electric motor you may as well make a normal electric aircraft.
Specialist_Reality96@reddit
Electric motors are really really good at going round and round, if the solution is not round and round they fall off a bit.
Invean@reddit
Since van Aert is with red bull you could probably get him to fly it across the Dover Strait
FIJIWaterGuy@reddit
That sounds like a bad idea without ailerons.
LaminatedParrot@reddit
Do you have the specs for the rebuilt wing? Curious to know the span, wing area and dihedral compared to the Aerocycles? Also the fairing and fuselage upgrades you are planing, any major deviations from the design inspiration there?
_jame5_@reddit (OP)
Currently it's identical to Aerocycle 301, dihedral is about 4 degrees.
This link should have most the wing specs for 301: https://www.humanpoweredflight.co.uk/hpfMedia/media/7/Aerocycle-plan.pdf
For the next fuselage we're going for a pod style design often seen on Japanese aircraft, with a prop diameter of about 3.5m, in a tractor configuration
ttystikk@reddit
The cockpit should be faired in as well, it will make a big difference.
_jame5_@reddit (OP)
its already on the to-do list!
ttystikk@reddit
I'll bet that difference will be significant in the overall performance and endurance of the aircraft.
flarne@reddit
Significant low for an airplane
Significant high for an "cyclist"
xjeeper@reddit
Yeah but what's the watts per kg?
0x7774663f@reddit
Surprised nobody else had mentioned watts per kilo yet! My FTP is 230W and I have a friend who has an FTP of 280W. He's stronger right? Yeah, he is...by a mile...on flats. Biking up a mountain to \~12Kft/3660m? I'll be sitting at the top for at least 30 minutes usually. He's a big muscular guy, over 6.5/1.8m where I'm almost a foot (0.3m) shorter with tree trunks for legs and almost no muscle anywhere else. His FTP in raw watts is almost 20% higher but in watts *per kilogram* my FTP is 20% higher than his.
_entrxpy@reddit
Mechanical engineering?
Aerospace engineering?
No, that's human engineering!
PSSE-B@reddit
I could maintain 400 watts for as long as the bear was chasing me.
AmazingSugar1@reddit
thecrazedlog@reddit
Ok, so, what we do, hear me out, is we get a horse, right...
flarne@reddit
My FTP is 230... Working on 250
Swimming_Way_7372@reddit
So happy to see the FTP talk in r/aviation. Trainer road is always trying to undercut my FTP.
aaronhayes26@reddit
400W is crazy for cycling. That’ll have most begging for mercy in seconds.
wighty@reddit
Dude gets to brag he has half the strength of a horse!
Conor_J_Sweeney@reddit
My PC draws around 1000W at full load and I've never seen it come close to getting off the ground.
CharAznableLoNZ@reddit
Put some delta fans in and it will.
Some1-Somewhere@reddit
You've only used gamer grade cooling fans then, not server ones.
Slightly /s but not really.
BirdLooter@reddit
37 kg is fucking crazy... like fucking fucking crazy... propably everyone of us could bench press the full plane. i don't know why this makes me so happy.
Jazzlike_Climate4189@reddit
The one that crossed the English Channel in 1979 weighed only 32kg.
BirdLooter@reddit
daaaaammmmmnnnn
FamiliarLettuce1451@reddit
This is awaome but ive always thougjt ehy isnt the gear ratio higher, its peddling against air, aurely you can go ham and have it spinning like mad easily
Jazzlike_Climate4189@reddit
*pedaling (peddling is selling stuff)
_jame5_@reddit (OP)
We will be making some adjustments, one of which will get the prop spinning faster. Too fast and it just generates a ton of drag for the same thrust, consuming power. A large slow propeller will always be more efficient than a fast small one. Our current one is 2.9m in diameter, once we replace the fuselage we will be looking at something like 3.5m for the diameter.
FamiliarLettuce1451@reddit
Ooo cool! Wouldn’t have thought that in a million years!! Can i be absurd and suggest two 3.5 diameter propellers?!
Hope my comments don’t take away from how super cool this is!!
flyingcaveman@reddit
Have you tried a single bladed prop? It's supposed to be the most efficient, but I would take your word for it if you tried it and said it was stupid to give a counter balance a free ride.
_jame5_@reddit (OP)
It's been done by a Japenese team, but we've never tried it. The prop is rotating quite slowly, so we think the efficency gain would be minimal, and then like you said, lugging around the counterweight is highly detrimental. You'd also need a larger diameter prop for the same thrust, which means a taller and heavier aircraft to keep ground clearance.
Zvenigora@reddit
Is that 400 watts just in ground effect, or can you climb out on that?
HMS--Thunderchild@reddit
Love it, is this a project for undergrads? very cool
Do you get much help from ground effect with an AR that long?
marcorogo@reddit
didn't hear a 'clear prop!!'
_Makaveli_@reddit
Not really a thing outside the US
marcorogo@reddit
it.... it was a joke.... :(
_jame5_@reddit (OP)
We shout that when we put the engine in the aircraft!
Tiny_Nefariousness33@reddit
Soooo What happened on the one unsuccessful landing?
_jame5_@reddit (OP)
We did an unscheduled experiment in large asymmetrical winglets
(A carbon - aluminum bond holding the wing sections together failed on the first flight, the pilot was completely fine)
_jame5_@reddit (OP)
_entrxpy@reddit
Guy in the back with his hands on his head, expresses perfectly what you guys were feeling in that moment lol
BeefHazard@reddit
My heart sank a little when the takeoff tally didn't match the landings, so glad it's just some unplanned harmless science.
IAmTheFlyingIrishMan@reddit
Nike: Just do it.
Specialist_Reality96@reddit
Having to pedal like fuck whilst flying an aeroplane. Something about cockpit workload, so this a student or research driven project?
_jame5_@reddit (OP)
Student project at the University of Southampton in the UK. It definitely feels like trying to rub your belly whilst patting your head sometimes.
Interestingly qualified pilots often struggle more to fly than RC pilots or non qualified ones - they try to use their feet to steer!
Mrcoffee864@reddit
As soon as the wheels leave the ground does he technically need to have a pilots license ???
Forest_Orc@reddit
Depends on the country. In some light powered Ultra-light don't require a licence in others anything leaving the ground needs a civil-aviation licence.
Practically speaking, aerospace engineering coming with a cool project like that will get away with-it, aviation authorities are full of nerds who like these cool/crazy project provided they're baked by serious persons (and is most likely how they got to use a real runaway)
_jame5_@reddit (OP)
We're in the UK, so no pilots license required (I dont have one and have never flown another aircraft solo)
We fly at Lasham airfield normally, and you're basically spot on - We fly early enough that we dont get in their way, and they think its cool.
satmandu@reddit
Would it make sense to just connect the pedals to a generator and use an electric motor connected to the propeller?
That's what Rivian spin-off Also is doing for the e-bikes:
https://arstechnica.com/cars/2026/04/first-look-alsos-upcoming-e-bike-disconnects-the-pedals-and-wheels/
_jame5_@reddit (OP)
It's been floated before, but its unlikely to work out lighter than a traditional drivetrain and you'd loose a ton of power in the generator and motor
immunotransplant@reddit
Nice
mpg111@reddit
so, there is no flying if you have too much for breakfast? just riding on a very wide bike path?
Space--Buckaroo@reddit
You would have made the Wright brothers proud.
No_Base_0815@reddit
That's a lot of pedaling for such a low engine speed. A better gear ratio would be more helpful, I guess.
WhatWouldLoisLaneDo@reddit
*ET theme intensifies *
nosecohn@reddit
Very cool.
Can you explain to a layperson how a regular human can generate 0.5 HP when a horse is more than twice as strong as a man?
_jame5_@reddit (OP)
A horsepower isn't the peak power output of a horse, its the output a horse can sustain over a day (I think). So for a short period of time a relatively fit human can pretty easily do 0.5HP. For sustained power a human is limited to about 100w depending on fitness.
nosecohn@reddit
That's a very clear explanation. Thanks!
yellekc@reddit
100W is a bit over 1/8 of a HP, so it will take 8 humans to do what a horse does.
West_Good_5961@reddit
Nah I’m good thanks
Bushwhacker474@reddit
this is just plain old cool
Ozzie_the_tiger_cat@reddit
Serious question: would it be a good idea to put a transmission like a 12 speed on the propeller so it would turn faster?
Ok_Witness179@reddit
To actually fly, or to hover in ground effect?
jjomal@reddit
Can you peddle an elastic band for 10 mins before and then take off with the rubber band assist? Or is that cheating? It has to be direct human power?
EvenMoreCoconuts@reddit
Credit to the person running, keeping up. Clearly out of breath at the end and gave it their all.
CarrowCanary@reddit
They're most likely also on a bike.
_jame5_@reddit (OP)
yep, still takes a decent effort to keep up though - I chased on a longer 2min flight and was knackered by the end
The-Sound_of-Silence@reddit
Do you have video of that one as well?
reddit001aa1@reddit
Did y'all rule out a bungie launch? I've launched rc jet aircraft with bunnies.
memostothefuture@reddit
Big respect to the camera operator. Marathon runner?
Whatever_Lurker@reddit
Were they cleared for that altitude?
withurwife@reddit
A340-300 takeoff
waidoo2@reddit
whats the science behind not having gears for faster propeller?
MilsYatsFeebTae@reddit
My guess would be that you don’t want any chance of chain skipping, could also be a weight issue.
trubol@reddit
r/ThatEscalatedSlowly
Ok-Helicopter525@reddit
Yeah but is it on Strava?
RestaurantFamous2399@reddit
Does this mean strava will have an airborne category to separate the flyers from the E-bikers now?
mishap1@reddit
The things people will do to hold KOM.
the_claus@reddit
This or ADSB out
baronmunchausen2000@reddit
Reminded me of this guy. In 1979 he flew across the English Channel in his human powered plane.
MacCready Gossamer Albatross - Wikipedia
FreedomsLastBreathe@reddit
Gnarly! Is that the elevator in the front?
nomadschomad@reddit
How’s it compare to Gossamer Condor/Odyssey?
Grinch420@reddit
TheEquationSmelter@reddit
I bet you could get more power if your pilot was able to both pedal and pump, like a Schwinn Airdyne exercise bike. You could probably gain controllability if the pilot shifted their weight, though it would require practice. What is the spar material, Balsa or composite?
_jame5_@reddit (OP)
The amount of power a human can output isn't limited by the legs, but by the lungs oxygen uptake, therefore adding arms would only help for a short period (which is why I think one human powered helicopter uses both to fly for under a minute).
Controlling the aircraft with weight has been done- unintentionally - and hasn't ever gone well. It's hard to do precisely considering the pilot weighs almost twice the aircraft and is prone to unintended inputs (especially as the pilot is putting out lots of power and moving around lots)
The aircraft is almost entirely carbonfibre, XPS foam and fibreglass on the wing skins
TheEquationSmelter@reddit
I would think using arms helps distribute the metabolic load more sustainably so you could reach the theoretical maximum power output. As an anecdotal example, 200W on a stair climber is compartively more difficult than on an elliptical or one of those Airdyne bikes. I also recently tried a versaclimber which was much harder than the stairmaster but I suspect had a very high power output.
If it were viable you could have the bike also turn a gyro which would provide stability without relying on aerodynamics though it would cut into your weight budget.
_jame5_@reddit (OP)
Maybe, but I imagine the added weight would offset any advantage. There's also the problem on controlling the aircraft if all four limbs are occupied.
A gyro would be too heavy it was was to be effective, and most the disturbances we get are vertical from wind gusts. Weight is a huge consideration of the aircraft and is minimised at all costs.
I_AM_FERROUS_MAN@reddit
It's a beautiful design for what it's trying to achieve. It's always satisfying to see airframes that are so obviously constrained by their use case.
HaggisAreReal@reddit
I am impressed. Is like if we had colour footage of those early 1900's prototypes
TheFlashestAsh@reddit
Very cool.
SaltInternational538@reddit
Congratulations. This is so cool. Thanks for sharing this with the world.
MikeOfAllPeople@reddit
These comments are a very entertaining crossover.
ValhallaAir@reddit
Are you on Skycards?
TreeFhiddy@reddit
Impressive, unless you understand ground effect
anandonaqui@reddit
The hubris required to make this comment is impressive, considering the team who build this is obviously very knowledgeable of aerodynamics and engineering in general….
_jame5_@reddit (OP)
We don't think ground effect has a significant effect - we've got such a short chord, as well flying so slow and our wing loading is so small that there isn't much of a high pressure bubble to provide any lift. In fact flying higher has proven beneficial for some longer flights (like the channel crossing in 1979) to get out of low level turbulence
Secure-Tradition793@reddit
Man-powered U-2!
Hot-Yam-0523@reddit
V1… rotate
bigolgape@reddit
13 knots...V1
exurl@reddit
Is a fairing/pod around the pilot up next? Also, is this the same HPA I spotted under a canopy at Lasham airfield last year?
_jame5_@reddit (OP)
Fairing is on the list for the new fuselage we have planned. When were you at Lasham? If it was in October it would have been Aerocycle 301 (an older aircraft, but with the same wing design), if during the summer it could have been this or one of the other 3 flying HPAs in the UK
exurl@reddit
I was there in June. Do all of the HPA teams fly at Lasham?
_jame5_@reddit (OP)
That would've been the Icarus cup, our annual competition. The aircraft you saw could've been ours, Airglow, or Aerocycle 301/302. Annoyingly all but ours look almost identical.
cawvak@reddit
Now, about lactic acid…
moneyfink@reddit
This is bad ass
Throwgasm69@reddit
Seen around Twyla
AmazingSugar1@reddit