Educational by Chapter of the Powered Paragliding Bible

I: First Flight

01 Training Process

02 Gearing Up

03 Handling the Wing

04 Prep For 1st Flight

05 The Flight

06 Flying With Wheels 

II: Spreading Wings

07 Weather Basics

08 The Law

09 Airspace   

10 Flying Anywhere

11 Controlled Airports

12 Setup & Mx

13 Flying Cross Country

14 Flying With Others

III: Mastery

15 Adv Ground Handling

16 Precision Flying

17 Challenging Sites

18 Advanced Maneuvers

19 Risk Management

20 Competition

21 Free Flight Transition

IV: Theory

22 Aerodynamics

23 Motor & Propeller

24 Weather & Wind

25 Roots: Our History

V: Choosing Gear

26 The Wing

27 The Motor Unit

28 Accessories

29 Home Building

VI: Getting the Most

30 Other Uses

31 Traveling With Gear

32 Photography


--- Not in book ---

33 Organizing Fly-Ins

34 Places To Fly

35 Preserving the Sport

36 Tandem

Effect of Weight On Speed & Glide, Small Wings

Heavier pilots go faster, how much faster?

We all know that more weight means more speed but how much? My wing reviews are obviously done with my 150 pound self so I'm unable to see what happens at real high wing loadings since they don't make wings that small. The Plasma 22 and Pluto 21 were the smallest production wings I've tried lately and my Spice 22 is too big for me. To get a high wing loading I have to fly a 17 and nobody makes those in enough quantity to call them production.

So how much faster would a heavier pilot go on a Spice 22? Thankfully, some brainiacs (Dana Hague and Carlos Curti) show us how. The formula is:

SQRT (New Weight / Original Weight) * Original Speed (either airspeed or sink rate).

For example, lets say a 300 pilot+wing+motor wants to know what his speed will be on a wing flown by a 250 pound pilot+wing+motor. He knows how fast the 250 pounder flies on that wing.

1. Calculate Weight Ratio: New Weight / Original weight. Lets say New Weight = 300 and Original Weight = 250. Weight Ratio is 1.095

2. SQRT (Square Root) ratio to get Speed Ratio. That's 1.2 here.

3. Multiply Speed Ratio (1.2) * the speed or sink rate to find out the new speed or sink rate.

If the original (250 pounder) reported speed of 25 mph you can see that HIS speed on that same wing will be 27.4 mph. And if the original sink rate was 400 fpm than the new sink rate will be 1.2 * 400 or 480 fpm.

Risk of Small Wings

I love small wings and it's tempting to keep going smaller but know the risks and tradeoffs. I've flown an 11 meter wing which was, not surprisingly, remarkably responsive.

1. What happens after a motor failure? If it happens just after takeoff, you'll be faced with a dramatic surge and dive at very high speed. If you're a foot off the ground, an immediate pull of brakes should keep the bones intact. If you're 10 feet off then a brief pause to allow slight surging to a mostly level attitude must be followed by nearly immediate flaring. If you're above 100 feet than all is well as you would have enough time to let the wing surge with some dampening (to prevent front tuck), establish a glide and do a normal flare. If you have not rehearsed fine pitch control already, the instinctive responses required cannot be thought out.

2. You'll be running really fast, especially in light wind and/or higher elevations. Tripping on surface perturbations will have graver consequences.

3. Another tradeoff is high fuel flow. Just like with reflex wings trimmed fast, it takes a lot of power to overcome our enormous drag.

4. Handling will be extremely sporty especially on models already known for sporty handling. I can only imagine what a 16 meter Spice would be like (admittedly I'd love to find out). A common cause of crashes on high end racing-type wings is an oscillation just after takeoff.

5. Lastly, although speed is great, if you do suffer a collapse the recovery will be "dramatic" at best.

So indulge in small wings carefully, understanding that with speed, inflation ease, and light weight, comes sharp teeth that will bite unwary bravehearts who don't pay appropriate respect.

Glide Ratio And Weight

Glide ratio can be expressed either as the lift/drag ratio or, more commonly, the distance you'll travel forward for the distance dropped, and its the same at any weight. Every glider has a speed/configuration that gives the best glide ratio and, in that configuration, (usually neutral trim, no speedbar) you'll fly the farthest distance in calm wind. Mind you, the speed at which best glide occurs will be faster at heavier weights but the glide ratio remains the same.

A heavy pilot will fly just as far from 100 feet as a light pilot on the same rig but the heavy pilot will get there faster. Both his sink rate and forward speed will be greater.

Note that power required is based on sink rate and weight so the heavier pilot, not surprisingly, requires more power to stay aloft than the lighter pilot.

Chad Bastian on his 19 m Ozone Ultralight. Mind you, Chad weighs in at about 120 and he's flying a 46 pound paramotor!


© 2016 Jeff Goin & Tim Kaiser   Remember: If there's air there, it should be flown in!