Dolphin flying

On Saturday, February 13, 2016 at 2:18:18 PM UTC-5, MNLou wrote:
Gentlemen -

One thing to remember - there is contest flying and there is non-contest flying.

While I understand that the theory is exactly the same, I would expect very different tactics between a Nationals contest flight and an OLC flight.

Especially for an OLC flight where time or speed is not a critical component, I would expect a more conservative strategy would be found to be the norm.

Lou

To sorta echo "UH's" comment...... the ONLY time I was allowed to, "Do something stupid that may break the glider..." was:
-Last day of a US Nats or worlds
followed by
-If it works, you win......."

Period.

Otherwise, "Train as you race, race as you train".

I agree that the US frowns upon "team flying" in it's contest, frankly (in disagreement to some on RAS), I think this is a TON more against the US doing well in the "world stage" than what type of tasks we tend to fly here (in the US).
A good team can have a high level of finish IF they help each other.
In the discussion of "leeching", depends on whether you are worried about US rankings or world rankings.

OK Sean F., have at it.

[back to stoking my fire, it's a "wee bit chilly" in north NJ. USA]

On Saturday, February 13, 2016 at 2:18:18 PM UTC-5, MNLou wrote:
Especially for an OLC flight where time or speed is not a critical component,
I would expect a more conservative strategy would be found to be the norm.

Absolutely wrong. OLC is a race, just like contests.
XC, you are always flying against the clock, the end-of-day, as fast as possible.
Otherwise you don't get home before sunset, end-of-lift, etc.
Time and speed is *always* critical.
IIRC explained in Reichmann ;-)

Jonathan,

Your approach is a good one and there is not an entirely clear answer. I think it really depends on the glider you're flying and your given situation. There are a couple things at play.

1) Time in lift/sink
2) Dynamic Soaring effect (from the pull-up)
3) Tactical considerations

So for the simple speed-to-fly indicator, it is telling you the optimal mathematical speed to maximize time in rising air. It does NOT assume the drag from a rapid pull-up. It is near to impossible to chase the needle and to do so would be inefficient in its own right. However, maximizing time in lift relative to sink is certainly a good thing and it makes sense to slow down in the good air or thermal. The question is how much. If you are in a relatively big area of lift and you can gradually pull up (1.5-2g max), then following the STF could make sense.)

Now, in some gliders you can pop off the air (dynamic soaring). This particularly works well with light wing-loaded gliders and/or gliders that have low induced drag and airfoils that are not prone to separation. In these gliders, dolphin flying carries a different meaning as you are extracting energy by the very act of pulling against the gust or thermal. The STF is irrelevant in these cases.

Some examples of gliders I had flown-

1) Schweizer 1-26E-

Great dolphining machine! The stiff wings and the very light wing loading let you pop off the gusts really well. The strategy for dolphining, especially into the wind is to slow down to minimum sink, sometimes even to minimum controllable airspeed and milk out the air as much as possible. The goal is to avoid turning at all costs. There is a huge amount of energy gained from dolphining/dynamic soaring off the vertical gusts. On a convective day in the East, it is possible to consistently achieve 25-1 glides by doing this.

2) LS-4

Mediocre dolphining glider. No flaps, so lots of drag on pulls. Much better to smoothly slow down to best glide, possibly to minimum sink if the thermal is quite big.

3) Standard Cirrus-

Awful dolphining machine. Huge airflow separation when changing angle of attack. But really great performance in club class just flying straight and smooth!

4) Duckhawk-

Unbelievably awesome dolphining sailplane. Auto-flaps, so perfect AoA on pull-ups, low induced drag, low separation make it conserve most of the energy on big deviations. Makes a lot of sense to pull hard and often.

(Listen to Bill Thar's speech at convention about Auto-flaps to learn more)

The tactical consideration is relevant in that there are two types of dolphin-flying. There is dolphining to get more altitude, and for greater speed, both which have a different technique. When dolphining for more altitude, I will cruise slower, pull more aggressively and slow down to minimum sink. When dolphining for "speed", I do gentle vertical deviations, less draggy, but to spend a bit more time in the lift compared to sink.

In practice, here are two scenarios-

1) You are going upwind and you have found a thermal street. You are climbing, drifting downwind. The question is when do you leave? You can leave earlier, slowly float up in the street by wafting up, or you can leave later and then blast along cloudbase. Generally I find it more efficient to leave earlier and waft up.

2) You are on final glide low. You need to make up 1000ft. Then dolphin more aggressively and pull out every bit of altitude. Once final glide is made, then speed up and don't deviate vertically as substantially.

Hope these thoughts were of interest.

Best Regards,
Daniel

Hank, Charlie, and Dave -

I should have made myself more clear -

For you "contest monsters" who focus on, fly, and win at the National level, of course you are always racing - even when you are practicing. That's what it takes to get fast. If you fly OLC, you max it out.

My contrast to a contest pilot was a pilot who flies XC but isn't trying to max out speed - just get around the course. Think a 200km triangle on a mid-summer day. Doesn't care too much about speed or how may OLC he/she gets. Just wants to have fun, go someplace, and get home.

I believe that pilot would fly more conservatively to maximize altitude and minimize the risk of landing out. A faster speed that eats up more altitude gains them nothing and potentially costs them big time.

Lou

On Saturday, February 13, 2016 at 10:54:32 PM UTC-5, MNLou wrote:
Hank, Charlie, and Dave -

I should have made myself more clear -

For you "contest monsters" who focus on, fly, and win at the National level, of course you are always racing - even when you are practicing. That's what it takes to get fast. If you fly OLC, you max it out.

My contrast to a contest pilot was a pilot who flies XC but isn't trying to max out speed - just get around the course. Think a 200km triangle on a mid-summer day. Doesn't care too much about speed or how may OLC he/she gets. Just wants to have fun, go someplace, and get home.

I believe that pilot would fly more conservatively to maximize altitude and minimize the risk of landing out. A faster speed that eats up more altitude gains them nothing and potentially costs them big time.

Lou

I do that sort of flying a lot (laid back, just wafting around the area), then again, I also do longer XC's from our place. We don't always get great weather, but if you want to cover some miles, you can't really just waft along, you need to keep the pace up.
My 500K took almost 7 hours (on thermals in southern NY), when it worked, I had to keep moving, when it didn't I went slow.
Not really any different than a contest flight, just longer.

Not saying everyone needs to do long flights, or "scorch the skies" for speed, some just like to get high and take a local tour. Nothing wrong with that.

But if you want to do contests, or, longer XC flights, you have to practice it (faster/more efficient flying), you can't just decide, "Hey, I never do it, but I will today!"
Just like doing a marathon, you really can't wake up one morning, pull on sneakers and say, "Hey, lets go do a marathon today". It will be a long day and you likely won't feel too good for a week or so after.

On Saturday, February 13, 2016 at 10:54:32 PM UTC-5, MNLou wrote:
Hank, Charlie, and Dave -

I should have made myself more clear -

For you "contest monsters" who focus on, fly, and win at the National level, of course you are always racing - even when you are practicing. That's what it takes to get fast. If you fly OLC, you max it out.

My contrast to a contest pilot was a pilot who flies XC but isn't trying to max out speed - just get around the course. Think a 200km triangle on a mid-summer day. Doesn't care too much about speed or how may OLC he/she gets. Just wants to have fun, go someplace, and get home.

I believe that pilot would fly more conservatively to maximize altitude and minimize the risk of landing out. A faster speed that eats up more altitude gains them nothing and potentially costs them big time.

Lou

I doubt that I fly much faster than you do between thermals when flying cross country. What I probably do more, and possibly better, is make modest changes in speed in response to or anticipation of air mass movement, and likely a lot more deviation to optomise my path so as to spend as little time in bad air as I can.
I don't land out all that often. The last off field landing I made from my home field was probably 20 years ago. My landings in fields in contests average about 1 every two or three years and I fly about 40 tasks a year.
The impression that contest pilots go fast by taking big risks is wrong in my experience. The percentages are in keeping risk as low as possible. That doesn't mean we're floating at cloud base, but we are being pretty careful..
UH

On Saturday, February 13, 2016 at 10:54:32 PM UTC-5, MNLou wrote:
I believe that ... would fly more conservatively to maximize altitude
and minimize the risk of landing out. A faster speed that eats up
more altitude gains them nothing and potentially costs them big time.

You are confusing flying efficiently (fast), and flying aggressively
(which periodically puts you on the ground, not fast)....

On Friday, February 12, 2016 at 2:46:48 PM UTC-5, Jonathan St. Cloud wrote:
Was reading an article by Mike Borgelt that when flying through a thermal you will not circle in you should just fly the STF.

I have always slowed in such thermals, sometimes slowing to thermal speed while putting the thermal flaps. I do try to accelerate before I leave the lift. My thought being try to stay in the lift as long as possible while still moving forward, sometimes even s-turning to stay in large thermal but still moving down the course line.

Would appreciate any comments, critique, thoughts...

i was always told by a very talented and well ranked pilot to never slow down below 60kts unless you are going to circle. i try to live by that, and have actually found that while one pilot pulls to thermalling speed, and i gently ease back to 60, he gets maybe 50 feet on me after he pushes back over, but i put distance on him. and i've always found that it's harder to make up horizontal distance vs. 50 or 100 vertical feet on someone (this is east coast dudes). remember that a pull is draggy, and also when you pull up and push back over, that's a "curve" in your flight path. when you only gently slow down to 60, you are flying a short path through the sky. when thinking in the "shortest distance between two points" mentality, remember to think in 3 dimensions. that's is my technique. its simple and effective i think.

On Saturday, February 13, 2016 at 6:46:48 AM UTC+11, Jonathan St. Cloud wrote:
Was reading an article by Mike Borgelt that when flying through a thermal you will not circle in you should just fly the STF.

I have always slowed in such thermals, sometimes slowing to thermal speed while putting the thermal flaps. I do try to accelerate before I leave the lift. My thought being try to stay in the lift as long as possible while still moving forward, sometimes even s-turning to stay in large thermal but still moving down the course line.

Would appreciate any comments, critique, thoughts...

The simple answer is to suck it and see, as it depends
When encountering lift, note the altimeter reading, then try any of the following: slowing down a little, a gentle pullup, a vigorous pullup and S-turn.

Could any of you shed some light on use of flaps while dolphin flying? I.e., in my DG-400, cruising at 70 - 75 knots with -4 degrees flaps, if I fly under a cloud and want to maximize the climb without thermalling, what is the best approach in terms of shifting gears with the flaps? I assume this is dependent on many different factors, but is there a general consensus about whether or not to down-shift to 0 degrees or positive (thermalling settings) flaps when flying straight?