[Bob Kuczewski]

The topic of "speeds to fly" can get pretty technical, and there are a number of resources available. This topic will start off with some general thoughts and may include those technical details later.

When people in hang gliding use the phrase "speeds to fly" they are generally talking about choosing speeds for optimizing flight time and/or distance (as in cross country flying). These differ from the immediate choices of speed needed for launching, landing, glider control, and obstacle avoidance.

The basic idea can be easily remembered by a pair of simple rules (first described to me by Joe Greblo during my training with Windsports). The rules are:

• Fly slow in good air.
• Fly fast in bad air.

It's easy to remember these rules because you want to stay in good air as long as possible (fly slow), and you want to get through bad air as quickly as possible (fly fast).

So what is "good air" and "bad air"?

Good air is air that is helping you. This is usually lifting air and/or a tail wind. Bad air is air that is opposing you. This is usually sinking air or a head wind. What about mixtures like lifting air with a head wind? That's where things get technical (and beyond the scope of this introduction). For now, just remember that you generally want to fly slower in good air and faster in bad air. The reasons and exceptions will be developed in this topic.

[Bill Cummings]

One exception to flying faster in bad air is flying
extremely fast on some modern double surface
gliders that are new to the pilots.
When HG started and with little exceptions we used
to hear pilot say, “Speed is your friend.”
As the higher performance double surface gliders
were coming out the big thing pilots were discovering
as the made their switch from single surface to double
was that flying near top end speed no longer felt friendly.
Still, flying faster than minimum sink speed (more on that
in later posts.) while in bad air is the better choice.

[Bill Cummings]

Pilot Gene Stone could not figure out how I was able
to return over the starting point of our tow road
with so much altitude. I was flying a single surface
glider and he was flying a newer double surface
glider. He hadn’t read up on speeds to fly.
He was speeding back before he sunk out and
that wasn’t working well. At high speed he was
offsetting his advantage by creating parasitic
drag and decreasing his glide over the ground
on his downwind leg. After telling him to fly
downwind at minimum sink speed (just above
stall speed.) he returned above the starting
point higher than me.

[Bob Kuczewski]

At high speed he was offsetting his advantage by creating parasitic drag and decreasing his glide over the ground on his downwind leg.

Good point. The drag equation is:

      Drag = q * CD * Sw

where:

      q = 1/2 * rho * v * v
      CD = coefficient of drag
      Sw = Surface area of the wing

That little formula contains a lot of information. For example, drag increases as a square of velocity (v * v). Drag is energy that is thrown away. And energy is either speed (kinetic energy) or altitude (potential energy). You generally want to conserve your energy so it is available when really needed (like advancing against a headwind). That's all part of the "speeds to fly" tradeoff.

[Chris McKeon]

First off, I want to say that title of this thread caught My Eye [ This is a thread, isn't it?]. Anyways "SPEADS TO FLY BY. Is it not to be up in the Sky Flying, is this not where We all Yearn to do?

I for one always tended to not concern myself with speeds to Fly By. Upon topping out in a Thermal. I would tend to pull in on the Bar, thus I would Fly Fast. I Flew My Predator. I mean The Preator with its incredible sink rate. I could always just count on My getting back up.

There is a reason that Pilots came up with the concept. I must learn more about [Speeds to Fly By]. The way I see it. It could only help Me to Stay up in the Air Longer.

[Bob Kuczewski]

I Flew My Predator. I mean The Preator with its incredible sink rate. I could always just count on My getting back up.

Always?

I have mostly flown Falcons and Dreams, and I could never count on them getting me back up.

[Chris McKeon]

Bob, You know it was a Sad Day in Hang Gliding when John and Company ceased build Predators. I Mean what a Glider it is, Pluss it is such an easy Glider to land. If a Pilot wants to remain Airborne, thus enabling Him to extend His or Her's Horizons. Yea it sure did work for Me.

[Chris McKeon]

"i AM ALWAYS A STUDENT"

I so do hope that One Day soon I will be able to know the Answers to Questions that I have asked some pf My Friends such as John Heiney. oh, I do not know how long ago now. that I asked John: "Dp You think that I will still be able to enjoy having Kick a** XC flights such as I used to have before I Pounded? John replied: I don't know, You have to remember that You are over Sixty Years ago. Well, I do know a way for John to convey that I am a Hundred Percent recovered. Well, how I would know that after flying say Johns North Wing T - Two, would be if John offered Me to Fly His 142 again, I do not know how long ago it was. But John and I were over at Fourt Funston One Day. Well back then I weighed oh around 230 - 240 Pounds, there abouts. So, the way I see it,, if I can still Fly like I used to, and if I will weigh no more than Two Hundred Pounds. Yes, John offered Me to Fly His One Forty-Two Predator.

My Wight is down, about Forty Pounds, Pluss or Minus. Same Glider, same Pilot, less Mass, why the Heck not? It has been I do not know exactly how long ago it was the last time that I flew a single surface Glider, call ot Thirty Yes: I am looking forward to it.

I have always been fascinated with Flight I still am fascinated with Flight.

[Chris McKeon]

OK I realize that when Flying an XC route I tend to Fly between thermals at a pretty much standard Speed, that Speed would be on the fast end of My Predators Speed range. The Speed in which that I would Fly between Thermals on a {{STRONG DAY|. Having my speed being Fast has served Me Well. I do not tend to blunder along on Glide where say being ignorant to when one of My Predators Wings upon fly through the edge of a Thermal, would experience lift. Say that would happen on the Port side of My Glider. Then as is standard, I would initiate a hard Left turn.

Just thinking about Flying has Ny Juices going. Heck the way I see it: We are truly blessed to ne able to Fly.

[Chris McKeon]

Optionally We should be able to count on Soaring as long as our Engine, Our Sun is shining up in the Sky, Heating Air, thus creating Thermals. It really did leave Me somewhat Perplexed by the People That I Would Meet upon landing in some Field Somewhere, after I had failed to locate lift, yes, A Thermal that Would cause My Predator to Climb back upback up to Cloud Base, Then Naturally I would go back on Glide. What I have been describing is this not what so Many of Us HG Pilots have experienced? I look at Flying Slow versus Flying Fast as this: Fly fast all the time. For You are up in the Air for a given amount of time. Better to Fly fast so that Your view f the scenery Changes. Remember to enjoy the View. For up until You experience some XC Flight ending Sink. You are still in the Game.