Since I'm a writer by habit and hobby, the kind of dreams I have must be proof that I have an active imagination. For some reason I don't often remember dreams but the one I had recently stuck with me for some reason.

In the dream, I came to awareness as I was driving down a gravel country road through beautiful rolling summer countryside. You know how sometimes you sort of drive on automatic and don't remember actually doing the driving? It was sort of like that. The last memory I had was that I was driving southbound on a road like that, but I had no idea of where I was. Since the road was gravel, I reasoned that I couldn't be as far south as Ohio, since they pave most of the country roads down there.

After some thinking about it I figured that a highway I knew had to be off to my right somewhere, but there were no roads leading to the right, just obvious driveways, but there were roads heading left which didn't interest me. I just kept driving on south, wondering just where in the heck I was.

Eventually, I came out of some woodland and saw a lake in front of me. It was nicely blue on this summer day; I could see boats and rafts, with the usual collection of cottages along the lakeshore. The only problem was that I still had no idea of where I was.

I was pondering this when I saw a river tugboat come around the bend pushing a couple of barges. That made me realize that this wasn't a lake, it was a river -- too big to be the Maumee, and too blue and narrow to be the Ohio. I would have had to drive a long way to make it that far south, anyway.

For some reason I stopped the car and got out to take in the scene. I was looking at the lake when I saw something dark gray floating in the water, ducking it's neck under water to eat like a goose -- but that was no goose! It was the size of a cow, judging by a fishing boat not far away. Whatever it was, people didn't seem to pay it any mind.

Life restoration of the holotype specimen of Pterodactylus antiquus, by Matthew P. Martyniuk.

I was thinking about going back to the car to get out the binoculars (I always have a set in the car with me) when the thing in the water spread its wings and lifted off. Without the binoculars I couldn't make out any details until it was above the horizon, and I could tell from the thing's silhouette that it was no goose -- it looked like a pterodactyl (I can't believe I spelled that correctly right out of my head, either!) I mean, it had the pterodactyl's mostly flying wing configuration, with no tail to speak of.

I was still looking at the pterodactyl until it flew out of sight. Something weird was going on! I got back in the car, drove north for a ways, then east until I came on a little country restaurant I've stopped at in my dreams before. It hadn't been real before, but now it was. I didn't think I was asleep, since things had too much clarity. The only thing I could think of was that I must have driven through a time warp or some sort of gateway to an alternate world when I was zoned out (or maybe it was why I was zoned out.)

I could foresee all sorts of interesting new adventures and was eagerly anticipating them when my wife's alarm clock woke me. She gets up two hours before I do; I usually sleep through it, but I didn't this time. Darn.

That was a fun dream and I would like to have enjoyed more of it. I can't help but think it would make a good start to a fantasy novel. Who knows? I might even write it!

One of the problems of the Internet is the sheer amount of data out there, and the fascination you can have by learning about a subject that you previously only had a mild interest in, but find fascinating for some reason. I've never heard of this syndrome being defined or named, but it happens to me all the time.

Last week I wrote a rather fanciful column about a dream I had, where I observed what looked to be a cow-sized pterodactyl. Now, I wasn't absolutely sure how to spell the word, so I turned to the Internet. One thing led to another and I blew away the afternoon in the process.

I soon learned that pterodactyls were actually only about the size of a goose, or perhaps better, a blue heron. But somewhere in the past I remembered that there were bigger ones. The flying reptiles of the distant past were correctly called pterosaurs, and the biggest one known, Quetzalcoatlus northropi, had a wingspan that was perhaps as much forty feet. That's a size of a small airplane. (I find it interesting that the species name, northropi, honors Jack Northrop, the man who essentially made the flying wing a practicality.) Albatrosses have wingspans that reach eleven feet, for example, a pretty big wingspan for a bird that weighs less than twenty pounds.

Reading the article about the Quetzalcoatlus northropi was interesting. There have been scientists in the past who have speculated that a bird that large couldn't fly. However, it's pretty clear that this pterosaur could fly, and as I read down this article I came across a name I knew from my own past: Paul Macready, who was the guy that proved that the old dinosaur could fly well.

I met Paul Macready briefly once long ago; his specific interest was in low-power, low-speed high-efficiency flight. In the late 1940s he was three times the national soaring champion, and once world champion. But he's better known for his work on human-powered flight; you might remember the Gossamer Condor, which was the first human-powered plane to fly a figure eight, and the Gossamer Albatross, the first human powered plane to fly across the English Channel. He was involved with the first solar-powered airplane, too.

QN and its builders. Macready is the only guy wearing a tie. From Macready's article "The Great Pterodactyl Project."

The Smithsonian Institution got Macready interested in the problem of pterosaur flight, and in 1984 threw a half-million dollars at him to build a half-scale model that could be used for an IMAX movie. Without getting to the details -- and they are fascinating -- Macready and his model pterosaur proved that control was a lot more complicated than anyone had realized, and that wings had to do several things at the same time. Macready and his cohorts wound up building a battery-powered radio-controlled model, in which a small computer handled the wing and other stability problems. This is nothing new; most new high-performance airplanes today are "fly by wire" in which a computer handles the difficult stuff while a pilot just tells it where to go. This model had a wingspan of eighteen feet, which he reasoned was all right to work on a model of an immature pterosaur.

QN in flight

Anyway, the QN, as it was called, worked. It had to be towed to get it off the ground but once there it could gain altitude on its own. In the few videos of the QN I found on the net, it didn't have the range of motion a bird has. I think it would be cool to see it fly, but it was destroyed in a crash when the radio control link failed. From what I can tell from web searching, there have been attempts to build larger versions with varying success, but they didn't have Paul Macready and a half-million 1984 dollars involved.

But my curiosity went on from there. I had always believed that orthinopters were pretty much a pipe dream, but no. A few years ago someone built a human-powered ornithopter, and several powered versions have been built. I saw another video of a small uncontrolled, pterosaur-shaped ornithopter flying around inside a guys workshop.

There are model ornithopters around, and some are quite successful. (In talking with a flying model builder friend later, he tells me that there are a number of ornithopter models built by hobbiests, and some are available commercially.) With all the media hassle about drones, I think it would be neat to have a bird (or possibly even a pterosaur) drone. Alas, I will never have that kind of money or interest.

It was a fascinating search, and it all came about because I wanted to spell pterodactyl correctly.

In thinking about the dream that started this line of thought, I realize now that I was reaching for the idea of a dragon. The traditional dragon flew, of course; we all have a mental image of one. In reality, the larger pterosaurs came about as close to the reality of a dragon as anything in the history of the earth.

Now, when I think about dragons and fiction, Anne McCaffrey's "Pern" books come quickly to mind -- people riding around on dragon-back. That's pretty fanciful, of course, but let's face it, we're dealing with fantasy anyway. But then when I ran across the Quetzalcoatlus northropi and Paul Macready's work on building a working half-size model, I got thinking real hard about the question of whether a human could have actually ridden a northropi, ignoring the 65 million year age problem.

Now, I'm not any kind of aeronautical engineer, but I've been exposed to the concepts a little from when I was a pilot long ago. I certainly do not have the knowledge or the intuition of Paul Macready. So, most of the aeronautics discussed here are taken from his article, The Great Pterodactyl Project. I am not sure where this article was published, but it's taken from the Caltech online library.

When Macready and his research group analyzed what relatively small amount is actually known about the northropi, they came up with some baseline figures including a span of 36 feet, a weight of around 140 pounds, and an aspect ratio (wingspan versus width) of 8. For the sake of ease of construction the working model they built was about half that size, with an 18-foot wingspan, with the idea that it represented a miniature or immature version of the reptile.

With that great a wing span and aspect ratio, a northropi had to have had some of the characteristics of a sailplane, which is to say it can fly all day if it can find air going up. For our purposes, load carrying capacity involves being able to take off and climb, not just jump off a cliff. The ability to get off the ground and power up to soaring levels is what determines payload. Let's arbitrarily say that the lizard had to have sufficient structural integrity to accomplish that with a large enough prey to make it worth the effort.

You can hear the weasel thinking, "This may not be the best idea I ever had." Photo by Martin Le-May courtesy BBC.

How much could a pterosaur really haul besides its own weight? For that we have to turn to birds. An eagle weighing 10 to 14 pounds can pick up a small animal or fish weighing in the range of five to six pounds, so for the sake of discussion, let's say 40 to 50 percent of body weight. Recently there was a photo of a European Green Woodpecker with a Least Weasel riding on its back. It is a pretty awesome photo, and probably not faked for a number of reasons I won't get into here. There's no way of telling without examining the actual animals, but a typical weasel of that species weighs around two to three ounces, while the average weight of the woodpecker is in the six to eight ounce range. That isn't real helpful, but puts the payload capability of the woodpecker in the 25 to 50 percent range of its body weight. However, one of the series of photos seems to indicate the bird flying at a high pitch attitude, so it had to have had the power to climb well with the extra weight.

So, let's assume that the typical pterosaur had a possible payload of a third to a half of its body weight. For a 140-pound northropi, that means it would have had a maximum payload somewhere around 40 to 70 pounds. It might easily have been more, since payload percentage increases with size, but that will work as a baseline figure and stay within the envelope. At the upper end of its range, then, it could carry a very small human being such as a child, a pygmy, or a dwarf. Since it probably would fly at 25 to 40 miles per hour, the pilot is not going to be in bare skin -- so much for the bikini-clad temptresses of some science fiction covers, for they would be too cold and windblown. Hitting an insect could be painful. That means there would also have to be the weight of clothing added -- the pilot would wind up being dressed something like a World War I fighter pilot.

Really, we need something bigger to be useful. The northropi is the largest known pterosaur, but who is to say that the fossils of an even larger one might not be found someday? Being a little arbitrary, let's make it half again bigger. We are now talking about a wingspan of 54 feet, an empty weight of 210 pounds, and a payload of 70 to 105 pounds and perhaps more as payload increases with size, up to a point. In fact, let's fudge several areas and make the maximum payload around 125 pounds, which not abnormally small for an adult human. We'll call the result a macrodactyl. I have flown sailplanes of this size (although heavier) and they fly very nicely -- but they did not have the power to get off the ground or gain altitude under their own power. The northropi probably could do this if Macready was right, and that means the macrodactyl could do it, too.

Guidance and control are an issue. Let's say that the macrodactyl is no more intelligent than a horse but just about as trainable. Unlike the "Pern" stories where the rider controlled the dragon by thought, reins might be needed to guide the macrodactyl. That would be interesting, for a horse only has to understand left and right (well, all right, gee and haw) while the Macrodactyl also has to be guided for up and down, as well. But, it ought to be do-able.

Without getting into the details, a macrodactyl is at least theoretically possible on paper. It sure would be fun to fly on one's back -- but there's that little problem of 65 million years. That's what the next article in this series is all about.

Macrodactyl in flight over an alien world. Photocompilation by Wes Boyd.

Where could people fly on a macrodactyl's back?

In my writing I try to stay away from fantasy and stick to things that can be extrapolated from reality. I haven't always been successful at it, but that's another story. In this case, I'm going to rule out approaches like Jurassic Park and time machines and at least try to stick to the realm of the vaguely possible, at least as we understand things at this time.

Interstellar space flight at less than light speed is at least theoretically possible, although there are plenty of engineering problems to be solved before someone sets out on a starship. I'm not going to get into those problems, but there are many good articles and books on the topic to pursue. I'd be willing to bet that it gets tried somewhere in the distant future assuming the world doesn't get too loused up along the way.

So, with that in mind, I'm going to wander into pure science fiction for a moment and do some world building. Actually, I've been working on this for some time, not that it's likely to turn into a story, but the macrodactyl fits right into the concept. This world, which I have not gotten around to naming, is vaguely Earthlike although smaller and denser with considerably more active plate tectonics. It is more geologically active overall, which among other things means more volcanoes.

The really important part of it is that it has an atmosphere with a sharper density gradient than earth. Air gets thinner with altitude, and it's more extreme here. On Earth, oxygen makes up about 21 percent of the air; on this world, it's closer to 40 percent, and there's more air to begin with. The important part of this is that humans are restricted to a rather thin layer of elevation; they can't get down to sea level because the oxygen partial pressure is high enough that they will suffer oxygen poisoning and die rather quickly. Conversely, they can't get too high in elevation without suffering oxygen deprivation, so there's a range of perhaps eight thousand feet in which humans can live.

It's pretty darn warm down in the lowlands because, like the greater air density change with altitude there is also a corresponding greater change in temperature with elevation than on Earth. It's also pretty darn cold year around at the high limit of human habitation, which narrows the human habitable band, too.

That this world is in a stage similar to the Earth's Cretaceous period, but where there hasn't been a Chicxulub dinosaur killer asteroid. In other words, it's in the late era of the dinosaurs. The lower elevations -- which partly overlap the area humans can handle -- are mostly dense jungle, which with a lesser percentage of ocean is part of why there's so much oxygen. Many of the "dinosaurs" eat vegetation, but there are some that hunt meat. The macrodactyls probably evolved to be so big so they could hunt bigger prey.

One of the reasons I decided to make the metrodactyls meat eaters is because of the greater energy available with the relatively small volume to process. I was going to make them plant eaters until I reflected upon cows, which have to eat high volumes of relatively lower energy food -- and then they have to dispose of that waste. I remembered a poem from when I was a kid that ended, "I sure am glad that cows don't fly." Falling manure is not a hazard you often see in science fiction stories. Incommmmminnngggg!

At some point someone decided to try and domesticate some of the smaller species. It worked for some, but not for others, but for whatever reason it was possible to tame a few lizards; eventually someone tried it with macrodactyls. The higher air density and oxygen pressure probably gave the macrodactyls a performance advantage over their similar species long ago and far away. You have to wonder about the person who would have been crazy enough to be the first person to try and ride a macrodactyl, but someone did it and over the years it has been moderately successful. Because of payload limitations, the riders had to be small and it might be strange to see a 90-pound woman training a beast with a 54-foot wingspan. But then it looks a little strange to see an even smaller 10-year-old kid at a fair on Earth leading and training a 2,000 pound steer, too -- yet it happens all the time in farm country with good 4-H clubs.

While I'm focusing on the flying lizards, this could be an interesting world in other ways. With humans restricted to elevations above sea level, areas of settlement are separated and might not be in real good communication with each other, which is why the metrodactyl riders are important. Our settlers have airplanes, of course, but they are few, far between, and need fuel while the metrodactyls can live off the land. The ocean is strictly a "no go" place, partly because of oxygen poisoning, but partly because there are things living in the ocean that would give a nuclear submarine pause if one were available.

The people of this world run rather small -- only rarely does anyone get over five feet or maybe 120 pounds. Although this helps with coming up with metrodactyl riders, I can think of a number of reasons why the people of this planet evolved over the generations into being little, only some of which involve the planet or deliberately breeding to ride the lizards. The human population is probably rather small (although I don't know how small "rather small" is) at least partly because this world is obviously a dangerous place and life can be short even if the settlers are careful.

There is a "critter problem," especially at the lower elevations, and the classic M-2 fifty-caliber machine gun isn't big enough to deal with the larger and more obnoxious species. The settlers have been forced to reinvent the rocket-propelled grenade. At the lower elevations it's necessary to live in armed fortresses and only till fields during daylight with a security team overwatch. It's still pretty dangerous -- and cold -- at higher elevations, but at least there the biggest and most obnoxious critters are altitude restricted too -- they can't handle the higher elevations or the cooler temperatures.

Fortunately the settlers have a lot of iron and heavier metals -- the planet has a high density, after all. They have built a couple of "tanks" to investigate the lower elevations, basically pressure vessels on treads, but they aren't used much because they're pretty dangerous and there are more important things to do, like survive.

What kind of society would evolve? What would the settlers be like? What stories would they tell? All I can say is that I might have to work on that one. I'm not really a science fiction writer, but every now and then I add a few twists to the backstory, even if I never write a book about it. It is something to think about, and at least I've had fun for a couple of days thinking about and researching this from the viewpoint of riding a prehistoric flying lizard, then writing this to show how an idea evolves.

I'm not sure that this is going to turn into a story or what, so I guess I'll just have to wait and see. Hope you enjoyed it!