GP Gliders GP 14 Velo has finally FLOWN!!!

On Mon, 28 Nov 2016 08:33:48 -0800, Tango Eight wrote:

On Monday, November 28, 2016 at 10:50:37 AM UTC-5, Tango Whisky wrote:
Well, on my airfield (and a lot of others here in Europe I know of), an
aborted aerotow at the end of the field (rope brakes, tug enigines
fumes...) will result in a total loss of the glider should there be no
instant supply of alternate propulsion.
Nothing to do with training : in this position at 100 ft off the
ground, the only choise is what to crash into.

Does this describe even 5% of PT3 accidents? It surely doesn't in the
USA, and that was my point.

I'm a UK glider pilot although I have flown ( briefly) in the USA:
however this thread is the first place I can remember seeing the term. As
you say that the eventuality that Tango Whisky described is not a PT3, I
suppose it must be a fairly specific term.

So, can you define it, please?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Monday, November 28, 2016 at 12:17:16 PM UTC-5, Martin Gregorie wrote:

So, can you define it, please?

It's a general term, the abbreviation stands for "Premature Termination of The Tow".

best,
Evan

On Monday, November 28, 2016 at 10:40:19 AM UTC-5, Tango Eight wrote:
On Monday, November 28, 2016 at 12:55:50 AM UTC-5, son_of_flubber wrote:
On Saturday, November 26, 2016 at 12:06:03 AM UTC-5, son_of_flubber wrote:
Will GP electric drive gliders be certified to aerotow with the boom deployed and the motor turned off? (Boom extended in case of PT3. Aerotow to save the battery charge for later in the flight.)

Sorry that I cannot point to specifics, but I read somewhere that towing gliders with the boom extended and the motor running is sometimes done in Europe in order to compensate for low powered tugs. This would be a good reason for GP to certify for extending the boom during aerotow.

As Andrzej noted, the prop on the GP has less drag when it is folded. And the motor looks sleek. And since it is electric, I'd guess that you could dial in just enough thrust to negate the drag of the extended boom (and save the batteries for later).

Being able to use FES to recover from PT3 is very appealing if you launch from a short runway with limited low altitude PT3 options. A plus if GP offered comparable functionality.

That said, as battery costs comes down and power density increases, aerotowing a self-launch capable electric glider will at some point stop making sense. Maybe that will happen sooner rather than later.

Do self launch gliders have the climb rate and stability to deal with strong sink on launch and the rotor associated with wave, or are they marginal on turbulent days?

Here I go, again. It's that perspective thing. If the subject is new toys and inventing the rationalization that gets them purchased despite the SO's concern about the bank balance, then I'm OT. If the subject is safety in launching, then Flubber's question is badly framed. I care about safety in launching, so:

The PT3s that are life threatening often *aren't the ones that a second power source is going to help with*. Wing down/bad ground loop at flying speed, controls not hooked up or other assembly fault, dive brakes open, canopy open, that sort of thing. Yes, you can invent scenario in which the electric miracle flies you away from an accident. More often, we see crappy PIC decision making turn a completely manageable situation into a very dangerous & sometimes fatal accident (I can rattle you off a long, sorry list of real, completely preventable PT3 accidents). Safety-wise, I remain an advocate for grasping the low hanging fruit first, and I still see plenty of it. It has nothing to do with new toys and everything to do with basic airmanship.

Who can name a PT3 accident that would have been prevented with instant-on electric propulsion that didn't have some other really obvious solution? I can't think of one off hand. I think these are rare.

Sitting in the back seat of our L23, I've watched nearly everyone I've flown with reach for something on the panel, fiddle with an air vent, look at a wing tip or do some other completely unnecessary thing below 500'. This can have consequences. The last PT3 we had at our airport was the guy who decided to retract his gear on tow, just because he could. Unsurprisingly, he got way out of position and next thing he knew, he was putting the gear right back down again! It doesn't get any more preventable than that.

If you want to improve your odds w.r.t. PT3 survival in particular, or emergency handling in general, the smart money is on training & critique. Increasing the complexity of your aircraft or procedures, not so much.

Evan Ludeman / T8

Someone correct me if I don't understand this right: Manufactures have to pay for specific test and submit to each country what they require and pay the certificate fee if they want a Standard Registration. With GP being a small company I can not see that they would go through the expense nor long wait to get standard Certs. I imagine that they would import as Experimental as do Ali Sport and others.

Today batteries take awhile to charge and even in the future if batteries are stronger, I would imagine they will still take awhile to charge. That being said, I think there will still be a need to tow Electric Self Launchers. At a comp, I would tow every day and use the batteries for not landing out. But I would not want to pull them out of the glider every day to charge. And my goal would not to use the batteries at all and not have to charge them every night.

People see things differently and safety is probably no different. I have seen an airfield where I would not take off nor land and have heard of accidents there. Just like I would never take off with a boom extended, running or not, electric or gas.

I think its great that GP is also installing BRS as standard. I know a test pilot that used a BRS twice successfully. Once by himself and once with a passenger.

Casey

On Monday, November 28, 2016 at 12:05:57 PM UTC-5, Mike the Strike wrote:
On Monday, November 28, 2016 at 9:31:24 AM UTC-7, Tango Whisky wrote:
Le lundi 28 novembre 2016 17:11:31 UTC+1, a écritÂ*:
Any worries about the motor eating the rope if it breaks/releases on the tug end? I'm sure the noise would be distracting...

Not really. I had the occasion to watch the rope being cut by the towplane pilot (it had to be changed, so we turned this into an exercise), and it actually drops well below the glider.
Now, if you are in a turbulent situation where you cannot control the slack anymore, that rope could be all over the place. That's why I wouldn't do push-pulls in such a situation.
Also, on a push-pull you need to have a briefing with the tug pilot. Ha has to known what to do if he encounters a problem during the take-off run (i.e. no brakes, evacuate to which side etc).

You probably wouldn't want to do this in low tow - the standard in some countries and many clubs. In turbulent thermals, I had the tow rope snake back over the canopy and wings a couple of times when my ballasted open-class ship over-ran the tug.

Mike

When in proper position for low tow the rope goes under the glider when released from the tug.
UH

What is the reasoning for some to prefer low tow position?

There seems to be a lot of confusion here.

I took aerotows when flying the Silent 2 Electro in Lithuania. Per recommendation from Luka, and the fact that it just made sense, I had the key and FCU on for the tow, after having done a quick motor check on the ground to make sure the electrons were flowing. In the event of a tow failure, it wouldve been easy to release the rope and motor away if that was the best choice.

There would be no reason I can think of and it seems like a terrible idea with the FES installation to attempt the run the motor with the rope attached.

That question (likely covered on RAS before....) belongs in it's own thread, NOT this one.

Please and thanks.

PS, yes, most of my aerotows are low tow, but I also train/use high tow.

On Saturday, November 26, 2016 at 12:06:03 AM UTC-5, son_of_flubber wrote:
Will GP electric drive gliders be certified to aerotow with the boom deployed and the motor turned off? (Boom extended in case of PT3. Aerotow to save the battery charge for later in the flight.)

Sadly this topic has been Flubbjacked.
I would like to hear more about the progress of the glider and some of the other projects these guys are doing.
I'd live to hear details about the motor, batteries, and motor control system they are using.
UH

On Monday, November 28, 2016 at 1:40:05 PM UTC-5, Tony wrote:

I took aerotows when flying the Silent 2 Electro in Lithuania. Per recommendation from Luka, and the fact that it just made sense, I had the key and FCU on for the tow, after having done a quick motor check on the ground to make sure the electrons were flowing. In the event of a tow failure, it would've been easy to release the rope and motor away if that was the best choice.

This 'instant on' feature of FES is 'icing on the cake' for anyone who flies from a field that has no good options for a PT3 at 100 feet and/or sometimes climbs slowly (over forest and boulder-strewn pasture) off the end of the runway due to strong sink. I think 99%+ of the risk-reducing benefits of FES (or a Boom electric) is the reduction of landouts in marginal fields. This benefit is small in regions with lots of good landout fields, and large in regions with relatively poor landout options and a storied history of damaged gliders and injuries associated with landouts.

On Monday, November 28, 2016 at 11:06:34 PM UTC-5, son_of_flubber wrote:

This 'instant on' feature of FES is 'icing on the cake' for anyone who flies from a field that has no good options for a PT3 at 100 feet and/or sometimes climbs slowly (over forest and boulder-strewn pasture) off the end of the runway due to strong sink. I think 99%+ of the risk-reducing benefits of FES (or a Boom electric) is the reduction of landouts in marginal fields.. This benefit is small in regions with lots of good landout fields, and large in regions with relatively poor landout options and a storied history of damaged gliders and injuries associated with landouts.

A smarter view to take is that the purpose of the motor is to reduce inconvenience.

Evan Ludeman / T8