PowerFlarm and ADS-B solution, can we find one?

On Thursday, January 7, 2016 at 6:20:32 PM UTC-8, Andy Blackburn wrote:
On Wednesday, January 6, 2016 at 7:36:27 AM UTC-8, Dan Marotta wrote:
In the spirit of technical discussion I must point out what seems to
me to be a basic flaw in logic.



The statement that you can gain or lose altitude at 10 m/s (~20 kt)
is certainly valid in the US southwest.* However the supposition
that two gliders traveling in opposite directions with 200 meter
vertical separation would be at risk of collision due to one
suddenly dropping and the other suddenly climbing in the same
airmass does not appear to be a serious risk.*

I think the idea is that they'd be in *different*, adjacent airmasses. Where you have strong lift you tend to have similar sink adjacent to the lift, this is true for wave, convergence and thermals. It's one reason why it's common to push over when exiting a thermal, so you can quickly traverse the sinking air surrounding the thermal (what goes up comes down somewhere nearby - that way all the air doesn't end up above the boundary layer). I've gained 1,000' pulling up in strong lift and I've seen similar opposite situations thunderstorm shelf-running. The climbing and descending gliders would not be maneuvering in the same thermal to be sure as it's hard to imagine in that case the pushing over into sink glider and the pulling up in lift glider doing anything other than diverging, but one glider pushing over to get through a veil of rain and sink while another glider is just pulling up into the strong lift under the shelf just beyond. You'd like to see that guy coming rather then letting him sneak in below the Stealth invisibility cloak and pop up into a conflict. Maybe it's just me, but I don't like surprises.

Part of the challenge with selectively degrading a device like Flarm is making sure you haven't made an assumption about the scenarios that can (or can't) come up.

9B

Some people do push over in lift, and nearly everybody pulls up in lift. If you are near cloud base in a thermal and you expect sink in the ring around it (very common), a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink. This is exactly when a glider entering is pulling up. 1000 ft is nothing in this scenario.

On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.

No.

T8

I'm with you, T8.

I read this exact strategy back in the 80s; I think it was in
Reichmann's book. I couldn't wait to perform a Split-S through a
thermal. I was a new guy and thought that would be cool. The "come to
Jesus" meeting at the end of the day with the other occupants of the
thermal was, shall we say, enlightening.

So here's my take on this whole Flarm "stealth" thing:

Those who want stealth mode, don't want others to be able to identify
them and become remoras. That seems a nicer word than leeches. They
state the reasons for their opposition in clear terms.

Those who don't want stealth mode want to be remoras but don't want to
admit it. In an attempt to push their view, they fall back on Mom,
apple pie, children, lawyers, and safety. We see the same arguments all
the time in other activities and they become more unlikely and extreme
with each round.

On 1/8/2016 3:59 AM, Tango Eight wrote:
On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:
a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.
No.

T8

--
Dan, 5J

On Friday, January 8, 2016 at 8:03:36 PM UTC-8, Dan Marotta wrote:
I'm with you, T8.



I read this exact strategy back in the 80s; I think it was in
Reichmann's book.* I couldn't wait to perform a Split-S through a
thermal.* I was a new guy and thought that would be cool.* The "come
to Jesus" meeting at the end of the day with the other occupants of
the thermal was, shall we say, enlightening.



So here's my take on this whole Flarm "stealth" thing:



Those who want stealth mode, don't want others to be able to
identify them and become remoras.* That seems a nicer word than
leeches.* They state the reasons for their opposition in clear
terms.



Those who don't want stealth mode want to be remoras but don't want
to admit it.* In an attempt to push their view, they fall back on
Mom, apple pie, children, lawyers, and safety.* We see the same
arguments all the time in other activities and they become more
unlikely and extreme with each round.




On 1/8/2016 3:59 AM, Tango Eight wrote:



On Thursday, January 7, 2016 at 10:24:34 PM UTC-5, jfitch wrote:


a correct strategy is to turn sharply 180 degrees from the intended departure direction and dive through the core so that you have maximum speed gain with minimum loss to traverse the sink.


No.

T8





--

Dan, 5J

Hahaaaaa!
New subject.
Jim

On Friday, January 8, 2016 at 10:03:36 PM UTC-6, Dan Marotta wrote:

So here's my take on this whole Flarm "stealth" thing:

Those who want stealth mode, don't want others to be able to
identify them and become remoras.* That seems a nicer word than
leeches.* They state the reasons for their opposition in clear
terms.

Those who don't want stealth mode want to be remoras but don't want
to admit it.* In an attempt to push their view, they fall back on
Mom, apple pie, children, lawyers, and safety.* We see the same
arguments all the time in other activities and they become more
unlikely and extreme with each round.

Dan, considering you don't fly with a PowerFlarm and don't currently race, your comments are somewhat simplistic.

I've had PF since the day it came out, and have raced with it (in your stomping grounds, by the way). I love the situational awareness it provides, and think it makes racing a lot more fun, as well as safer. If you carefully read all the threads on this subject, you find a few hard core "IT WILL RUIN RACING AS WE KNOW IT!!!" proponents of stealth, a few hard core "MANDATE STEALTH AND ILL NEVER RACE AGAIN", and a lot of "I really like full flarm SA and I worry about mid-airs, is there a way we can compromise? My personal take is that the leeching argument is way overblown with the attendance at US contests, otherwise everybody would be carrying binoculars and all the young guys with 20-10 eyes would be winning. And having picked up USAFA Duo's(all USAFA racing gliders have PF) head on co-altitude under a cloud street over 10 km on the nose, I REALLY dont want to give up that capability.

All this knashing of teeth about how to tweek "stealth" to "competition" that will please everybody seems pointless to me. As others have pointed out, ADS-B out is coming, and if a cheap 1090ES system for UAVs comes out soon, I bet you will see it explode in gliders, and with PF you will see all those guys regardless of stealth or competition modes.

Instead of whining, we should all embrace the new technology and the capability it brings, and find new ways to use it. Despite what many nay-sayers are claiming, for the average racing pilot full up flarm makes a contest more enjoyable and safer - and isn't that really the point of it?

You should borrow a portable PF and try it - you may find that opens your eyes on what is really flying around in your airspace - you'll be able to see those airliners deviate around you!

Cheers from cold, wet, dreary St Louis.

Kirk
66

Well said Kirk.

The premise of this thread, that there should be some acceptable way to degrade the behavior of a safety device is just off base. We should only be looking to Flarm folks for ways to improve safety performance. That is their mission - no nonsense, no confusion about goals please.

Hi Kirk,

Yes, I've towed you during at least one contest at Moriarty and I've
admired your LS-6.

Please understand that I don't "poo-poo" Flarm in my comments, I only
respond to the comments of some, which I believe are unreasonable or
downright wrong. I always welcome logical proofs like the math-based
analysis of the pull-up (in a previous thread).

And yes, I think Flarm is a great tool for situational awareness but I
don't think that knowing a blip's ID is a requirement for safety. And
I'm neither for nor against "stealth" mode - I don't care either way.
The idea of coordinating an escape plan with another aircraft 5 miles
away by radio is simply ludicrous. Remember when contests were fully
manned and there was no Flarm or GPS? I'm not against either, as a lot
of the folks here think, but I think a lot of the fun has gone and
that's the main reason I don't fly contests any more.

So why do I keep posting? It's out of a genuine concern that false
perceptions, unchallenged, will eventually become policy, and I don't
want any more policies.

On 1/9/2016 8:09 AM, kirk.stant wrote:
On Friday, January 8, 2016 at 10:03:36 PM UTC-6, Dan Marotta wrote:

So here's my take on this whole Flarm "stealth" thing:
Those who want stealth mode, don't want others to be able to
identify them and become remoras. That seems a nicer word than
leeches. They state the reasons for their opposition in clear
terms.
Those who don't want stealth mode want to be remoras but don't want
to admit it. In an attempt to push their view, they fall back on
Mom, apple pie, children, lawyers, and safety. We see the same
arguments all the time in other activities and they become more
unlikely and extreme with each round.
Dan, considering you don't fly with a PowerFlarm and don't currently race, your comments are somewhat simplistic.

I've had PF since the day it came out, and have raced with it (in your stomping grounds, by the way). I love the situational awareness it provides, and think it makes racing a lot more fun, as well as safer. If you carefully read all the threads on this subject, you find a few hard core "IT WILL RUIN RACING AS WE KNOW IT!!!" proponents of stealth, a few hard core "MANDATE STEALTH AND ILL NEVER RACE AGAIN", and a lot of "I really like full flarm SA and I worry about mid-airs, is there a way we can compromise? My personal take is that the leeching argument is way overblown with the attendance at US contests, otherwise everybody would be carrying binoculars and all the young guys with 20-10 eyes would be winning. And having picked up USAFA Duo's(all USAFA racing gliders have PF) head on co-altitude under a cloud street over 10 km on the nose, I REALLY dont want to give up that capability.

All this knashing of teeth about how to tweek "stealth" to "competition" that will please everybody seems pointless to me. As others have pointed out, ADS-B out is coming, and if a cheap 1090ES system for UAVs comes out soon, I bet you will see it explode in gliders, and with PF you will see all those guys regardless of stealth or competition modes.

Instead of whining, we should all embrace the new technology and the capability it brings, and find new ways to use it. Despite what many nay-sayers are claiming, for the average racing pilot full up flarm makes a contest more enjoyable and safer - and isn't that really the point of it?

You should borrow a portable PF and try it - you may find that opens your eyes on what is really flying around in your airspace - you'll be able to see those airliners deviate around you!

Cheers from cold, wet, dreary St Louis.

Kirk
66

--
Dan, 5J

On Saturday, January 9, 2016 at 12:14:07 PM UTC-5, Dan Marotta wrote:
Hi Kirk,



Yes, I've towed you during at least one contest at Moriarty and I've
admired your LS-6.



Please understand that I don't "poo-poo" Flarm in my comments, I
only respond to the comments of some, which I believe are
unreasonable or downright wrong.* I always welcome logical proofs
like the math-based analysis of the pull-up (in a previous thread).



And yes, I think Flarm is a great tool for situational awareness but
I don't think that knowing a blip's ID is a requirement for safety.*
And I'm neither for nor against "stealth" mode - I don't care either
way.* The idea of coordinating an escape plan with another aircraft
5 miles away by radio is simply ludicrous.* Remember when contests
were fully manned and there was no Flarm or GPS?* I'm not against
either, as a lot of the folks here think, but I think a lot of the
fun has gone and that's the main reason I don't fly contests any
more.



So why do I keep posting?* It's out of a genuine concern that false
perceptions, unchallenged, will eventually become policy, and I
don't want any more policies.


Thank you Dan for your posts. Your opinion is important, too. I especially agree with this last paragraph.

I'll give you one example that needs to be challenged stated just a little while back. One post says"the requisite 45 seconds" and goes into some simple calculations based on 45 seconds on the display. I would like to see some actual physics calculated, but aside from that there is no basis for the 45 seconds. This is the kind of overstatement I keep talking about. It is not a lie but people are trying so hard to make their case for the outcome they desire they sometimes overstate the facts.

Pull out your iPhone and run the timer for 45seconds and you'll see it is a lot of time. There are other alternatives that may help. When a new target appears on the screen there can be simple audio alert letting you know of the new bogie. I would suggest that in this case 25 seconds of warning is plenty if collision avoidance is what you are really after. Don't take my word for it though, use some real science to come up with a real number.

The TCAS operators guide that I am looking at allows 5 secs as the outside reaction time to initiate corrective action (pitch change in the case of TCAS) resolution advisory. This is similar to the FLARM warning when a collision path is detected. I don't have complete TCAS specs readily available but perhaps other time values from TCAS could be used since their research is probably more thorough.

It makes a big difference in the final numbers if you use 45 seconds or 25 seconds. Let's make sure these numbers are based on some evidence.

XC

On Saturday, January 9, 2016 at 12:08:39 PM UTC-8, XC wrote:
SNIPLet's make sure these numbers are based on some evidence.

Based on evidence presented so far, we don't even have a need for a stealth, so that is an odd statement.

The 5 second TCAS has got to be a minimum, panic mode number. Also do not just consider the case of one glider meeting one glider. Consider 5 gliders meeting 5 gliders. No longer can you just turn right or pull up, doing so may well cause an accident rather than prevent one.

XC,

Again, you assume the flawless function of the Flarm system. 25 seconds, if the Flarm "network" is not perfectly functional due to say structural interference, may be reduced to 5 seconds. Or zero. Arbitrary discussions about were "safety ends" and "philosophical Flarm fairness?" (whatever the hell this should be) begins has proven quite frightening to observe.

The longer the time period the Flarm has to make a potential warning (beep as "bogey" appears), the better. This is a fact (from a safety viewpoint). Artificial reductions in Flarms engineered performance potential will by definition also increase the odds of a dangerous situation occurring. While being far better than nothing, the Flarm network is still prone to regular coverage challenges and clearly does not have, perfect, 100%, 360 degree coverage at all times. Far, FAR from it.

We need to kill this whole idea for at least one year. It's out of control.. It is irresponsible (at best) to screw around with Flarms potential range at this point. The unintended consequences are potentially huge. The philosophical competitive "fairness" argument is simply no peer to safety. It's not even on the same planet as safety. Stop treating this discussion like this as a debate between equals. Start respecting the fact that Flarm, while valuable for safety, is far, far from perfect or infallible. So when you say a supposed time value that you find acceptable for your little crusade, imagine that the gliders 25 seconds away from a potential collision are not seeing each others antenna at 25 seconds for whatever reason. Or maybe you get a proximity "beep" and then lose coverage for 15 seconds.

Bottom line, some here care far more about philosophical fairness arguments than the significant safety value Flarm provides via its ability to create situational awareness for us. This crusade become an literal obsession for some.

I won't debate or compromise Flarm at this point until some sort of impartial, objective study (and extensive testing) has been completed. This was the requirement of my initial support for a limitation. Since then, the almost reckless abandon that many supporters (almost certainly coordinated in a pseudo RAS Flarm "mode" campaign) have demonstrated here is a real problem. The USRC opinion poll does not support this desperate position.

Perhaps the FAA should be involved. Has anyone discussed this topic with the FAA? I wonder what their take would be.

Sean