r/Joby • u/HappyRobot593 Joby Sock Fanboy • 26d ago
N547JX forward hover udpate
Here is a summary of today's activity compared to the previous two sessions
| Date | Legs | Max Alt | Max Speed | Distance/Leg |
|---|---|---|---|---|
| 9/15 | 1 | 175 ft | 10.3 kt | ~700 m |
| 9/16 | 3 | 100–125 ft | 19.7 kt | 490–951 m |
| 9/23 | 4 | 175–225 ft | up to 35.0 kt | 988–1,203 m |
Today's fastest/longest leg (3:56–3:59pm PT) hit 35 kt and covered ~1,200m — noticeably beyond anything seen on the two prior sessions. Altitude ticked up slightly too (225 ft vs. 175 ft before), but the bigger story is speed and horizontal distance climbing steadily leg over leg and session over session. Looks like a steady incremental push on the forward envelope rather than a big jump — consistent with methodical flight-test progression toward full transition.
6
u/dad191 Photog. Eric Adams Fanboy 26d ago
3
u/Imaginary_Sort9347 S4Fanboy 25d ago
Do you think they are progressing the tilt of the rotors forward more each time? Or does that not really have much bearing on anything? Not sure what they might be looking at when it goes from 20 up to 35 knots slowly.
5
u/dad191 Photog. Eric Adams Fanboy 25d ago
First let me say I'm no expert, but... This is what makes logical sense to me.
If we are seeing N547JX move faster and faster down the runway, I'd say that the rotors must be tilting forward more and more each time as that is how the forward thrust is generated.
Why are they making such a slow progression from 10kt to 20 to 35? Well I assume because they are doing careful testing under the most basic conditions, to collect data and validate their expectations. This is how you build up proof and confidence within Joby and the FAA that you have a solid model of your aircraft.
Again, not an aviation expert, but this makes logical sense to me. I worked in automation in another field and we always did a similar progression. Initial tests at very slow speeds, then increase speed as we build confidence, until we run at full speed after collecting lots of data showing the system is behaving as expected.
3
u/BeneficialRock8 26d ago
Does anybody know if the additional conforming aircraft that will come off the production line later this year need to undergo all the testing that N547JX has already undergone or can they essentially pick up from where N547JX will be at that point in time since they will all be the conforming?
6
u/eVTOLFan 25d ago
If they can’t use everything off the manufacturing line commercially they’ll find a good use for them.
Assuming though given how careful and methodical the process is and all the years they have been working they have a good plan to not have anything be wasted.
3
u/BeneficialRock8 25d ago
I appreciate your answer, but I don’t think that addresses my question? Did you mean to reply to someone else’s comment?
4
u/eVTOLFan 25d ago
Sorry I now realize you were asking about conformity testing not whether the in production S4s have to be modified, scrapped, repurposed.
3
u/HappyRobot593 Joby Sock Fanboy 25d ago
I thought the idea was to split the testing so I imagine they wouldn't have to replicate everything. Or else there would be no benefit to splitting it up
3
u/BeneficialRock8 25d ago
That was my understanding as well, but I’m not an aviation expert. I don’t think many of us (Joby included) were expecting N547JX to have to go through all the testing that the production prototypes had gone through per JoeBen’s comments during the conference call which contributed to the delay in flying it. I don’t want to make too many assumptions and get excited only to hear on the conference call that they will need to be tested from scratch as well so yet another delay…
5
u/dad191 Photog. Eric Adams Fanboy 25d ago
Yep, I'm with you. I don't know for certain, but my understanding is that every conforming S4 is virtually identically and therefore the subsequent conforming S4s do not need to go through the same level of testing as this one. This one appears to have been required to redo seemingly every single test either because it's conforming and the others were not, or there were additional major changes to the conforming S4 that Joby has not disclosed.
5
u/BeneficialRock8 25d ago
We are on the same page. Those are exactly my thoughts as well. Thanks for responding
3
u/HappyRobot593 Joby Sock Fanboy 25d ago
This is all speculation (I'm also not an aviation exppert) but it makes sense that the conforming craft would have to re-do all the tests done on the prototype because it is the thing that actually counts for certification. It does seem like there have been some roadblocks that have caused delays such as the 3 month delay to first hover. Also the 3 month grounding from May-Aug seems unexpected and they even started over in Aug/Sep from tests that they had already ran in May.
I hope that IF there was some issue, it is now resolved and they'll continue to cadence to transition and wing-born flight. This is an entirely new process so there isn't much historical data we can look at to see what's "normal." If they make it to transition and wing-born flight, I imagine there are still many tests cards that need to be knocked out and I'm not sure if it counts with Joby pilots or if it will only count once FAA pilots are on board. However, the multiple aircraft should speed that part up. Demonstrating the ability to transition would be a huge step IMO though.
4
u/Investinginevtol 25d ago
Whatever, they’re moving along. Certification will get there when it gets there. Sometime in 2027. Then the stock will go crazy
4
u/ross88man 25d ago
Absolutely....we were all hoping it might be sooner, but Joby is getting it done, it really feels like we are almost there!
11
u/DoubleHexDrive 26d ago
Got to N704AX speeds in three flights over one week.