2) Was the entire course programmed into the plane? This is non-trivial given that high winds would likely push a small little plane off course.
3) Article claims that GPS telemetry was sent continuously. What did they use? Wifi doesn't work. There are no cell towers in the ocean. The only option that could remotely work is satellite data. That costs a fortune and has heavy equipment.
#3 is the big one.
EDIT: I am still skeptical but less so after reading the child comments. It seems HAM radio was used to relay telemetry. Communicating with a tiny moving object via HAM still seems a bit unbelievable. But I don't know enough on this subject. Also, the craft was supposedly using auto pilot over the Atlantic. I don't see how it is an RC craft ... perhaps a UAV would be a more appropriate term. Anyways, upvoting child posts for a stimulating early morning thought exercise :)
Slightly OT, but a former coworker of mine flew gliders as a hobby. Like an ultralight airplane without an engine, they get towed up to 10000 sq ft and then glide.
Guess how long they can stay in the air? Hours. Gliders stay afloat by finding hot air streams where clouds are forming, riding the plume up, then gliding to the next cloud.
It's not what this RC plane was doing, obviously, but posting it as an example showing how fuel can be irrelevant in the air. It's also an amazing hobby for one to have. He has all sorts of stories about the weather changing and having to crash in a farmer's field...
My father and stepbrother used to do this as well. Lots of interesting stories came out of it - having a heart-attack five thousand feet up, landing in a farmer's field and convincing him to put down the shotgun...
1) once you are at altitude engines are amazingly efficient. I still can't believe 1 liter got them across the Atlantic, but 100s of km, definitely.
2) Decades before GPS there was gyroscopic navigation. There has been autopilot for RC planes since as far as I can remember, for me the 90s.
3) There are many other radio bands available besides 2.4GHz. And satellite is not the only option. You have packet radio, marine radio, and HAM (amateur radio).
It wasnt continuous telemetry from memory, just once an hour. The power consumption would have been huge otherwise. Cant remember how they were transmitting, but probably radio, which is why they didnt get the signal for 3 hours.
Also remember the wind is behind you flying that way across the atlantic. Helps a huge amount in terms of power required.
1 litre of fuel could work with an engine that has a cylinder of a few cm3. Telemetry was probably by HAM radio or something similar. Nothing fancy like WiFi or satellite.
The numbers for 1 litre of fuel don't really add up, either. They said the flight took ~38 hours, but when it landed it had ~ 2 ounces of fuel left, which would have "[left] it less than an hour left before it would have crashed".
~34 ounces per liter, ~2(+) ounces per hour, implies >2 liters for the flight.
The speeds are about right, though: 1800 miles/55mph=33 hours, /42 = 43 hours.
I've been in the testing labs of InSitu, the company which makes the logical descendent of the Aerosonde (ScanEagle). I'm a software guy, and know nothing about engines, but tacked onto the door was a reminder that each paper clip's worth of weight that was shaved off the vehicle extended its range by something like 50 km.
3) Article claims that GPS telemetry was sent continuously. What did they use? Wifi doesn't work. There are no cell towers in the ocean. The only option that could remotely work is satellite data. That costs a fortune and has heavy equipment.
They probably used amateur packet radio to transmit telemetry. I suppose it may be hard to believe if you're not a ham, but this is a rather common usage scenario, even over long distances.
Who cares if it was actively RC or not?!? It's still quite an achievement that the plane could fly autonomously across the Atlantic.
Imagine that: in less than 100 years since the Wright Brothers took off, we have a hobbyist autonomous plane that flies across the Atlantic. That's a huge achievement nevertheless.
I remember reading about this a while back. Sadly, said plane was not considered for a world record because the RC community felt that even though it only used auto pilot for the in-air part, only RC planes that were remote controlled for the entire voyage should be considered for records.
Within the colloquial definition, the plane is of a class known as 'RC planes' - it's of a size and general design pattern that is conventionally controlled by a ground based radio pilot, it couldn't be used for carrying passengers, goods or weapons. For very sensible techincal reasons it had to run on autopilot for much of its journey, but the vehicle itself was still undeniably a member of the class colloquially known as 'RC planes'.
By analogy, let's suppose I purchased a retired F1 racing car for whatever purpose. I don't have the entries, licenses and any of a number of other things to enter it into FIA sanctioned F1 races, but does that stop it from being an F1 car while it's not being used for F1 races?
1) 1 litre of fuel doesn't get you that far.
2) Was the entire course programmed into the plane? This is non-trivial given that high winds would likely push a small little plane off course.
3) Article claims that GPS telemetry was sent continuously. What did they use? Wifi doesn't work. There are no cell towers in the ocean. The only option that could remotely work is satellite data. That costs a fortune and has heavy equipment.
#3 is the big one.
EDIT: I am still skeptical but less so after reading the child comments. It seems HAM radio was used to relay telemetry. Communicating with a tiny moving object via HAM still seems a bit unbelievable. But I don't know enough on this subject. Also, the craft was supposedly using auto pilot over the Atlantic. I don't see how it is an RC craft ... perhaps a UAV would be a more appropriate term. Anyways, upvoting child posts for a stimulating early morning thought exercise :)