tomjnx wrote:
And even though not especially fire- or crash proof, it seems to be that quite often the nonvolatile memory is still readable after a crash. So why make it expensive for the odd case where the NVM is destroyed as well?
Agree, and there a memory solutions which are robust.
tomjnx wrote:
I suspect what you found is more inadequate algorithms than sensor issues
I think you are partially correct. For this project we have tested many gyros, including the algorithms supplied. Although many claim to be very good, few give actually specification. From low cost, upto expensive units (at about 5K) where unsuccesfull. The only unit which functions quite ok for aerobatics is a 10K sensor, which is far to expensive to make this worthwhile for GA at this point.
Even technical support from these major units gave up. You will also see this incorrect information on many PDF’s even those of major manufacturers. For level flight etc most are ok, high dynamics is a different situation.
Peter wrote:
Neil – I don’t think you can connect aircraft data to these portable devices. There is not much of a problem just recording video – I eventually converged on the Roadhawk as the only product which would genuinely record the “last X hrs” of a flight (all the webcams e.g. go-pro cannot do “continuous loop” mode) but got rid of it because it didn’t have enough resolution to show the whole panel.
The Garmin Virb XE records GPS data including location, speed, track, altitude, etc.[edit : From it’s own internal GPS] It is waterproof to 50M. It has a microphone. It can record in a continuous loop, see THIS. Resolution is 12MP.
It also has a protocol to link to other data sources for things like engine data (used in Motor Sport).
Jan Olieslagers wrote:
There was a famous case a couple of years ago when a SEP ditched in the North Sea after reporting engine trouble. The wreckage WAS salvaged and the FADEC logs could still be read out! Much to the regret of the owner/pilot…Official report
The link is dead for me. Could you post it again / store it somewhere else?
tomjnx wrote:
And their higher bias instability compared to a mechanical gyro or higher cost IMU sensors don’t seem to be much of an issue in this type of motion
I did have a look at that datasheet. They don’t specify a bias drift for this one at all, quite sure it won’t be to impressive. Especially during constant aerobatics it is important that it has a low drift, else it will become unreliable quickly. You really want it to be accurate within one degree. A 3 degree error would be quite visible after some aerobatics would be quite visible.
Many people and companies IMHO overestimate MEMS sensors for this. Video’s like with the Panthera spinning show that.
Jan_Olieslagers wrote:
Look here
Thanks, now I’ve been able to download it.
I am not doubting there is a way to collect and record the data. I just wondered why nobody was making a proper crashproof recorder.
I guess there would be minimal uptake, for privacy reasons. In professional flying, the operator is the one you sue, not the pilot. In GA, it is usually the pilot who is relying on the insurance.
I can see a club using such devices, or the owner of a for-rent plane, if for no other reason than to know who not to rent to, or to be able to prove the pilot was at fault, not the maintenance. The clubs alone I’d think would be a worthwhile market, assuming a useful device (put in card before flight, remove post flight, put into computer, see nice graphics) could be delivered for a reasonable cost (and I don’t have any idea what ‘reasonable cost’ would be). I know our club put in GPS devices that record the flights, similar to those used in cross country navigation competitions. I’m not sure what their rationale was.
In GA, it is usually the pilot who is relying on the insurance.
There could be a reduction in premiums, like they do for cars nowadays.
