[Spaceships] Ornithopter Wings no longer TL5+2!

[RyanW]

Originally Posted by sir_pudding

The V-22 has been in service since 2007. There's been only one crash since then and it was a pretty typical combat aircraft incident (and could of happene to any aircraft under the same circumstances).

And of the four prior crashes, three were general failures that could happen to any aircraft (especially a new aircraft undergoing testing) and the other was due to vortex ring state.

The investigation of that crash revealed that the Osprey is actually more resistant to entering, and more easily recovered from, a vortex ring state than a conventional helicopter. The pilot in that case just let the sink rate get way too high, about twice the allowed limit, and flew down into his own prop wash.

[Phoenix_Dragon]

Originally Posted by sir_pudding

The V-22 has been in service since 2007. There's been only one crash since then and it was a pretty typical combat aircraft incident (and could of happened to any aircraft under the same circumstances).

The Marines seem pretty happy with its reliability, too. Based on the past decade of flight hours, the Osprey had an accident rate about half that of the USMC aircraft fleet's average, and less than any rotorcraft in the USMC. Of course, it has the benefit of being younger than many of those aircraft, but it's apparent enough that it's not the death trap some seem to think it is.

[Tzeentch]

Originally Posted by Phoenix_Dragon

The Marines seem pretty happy with its reliability, too. Based on the past decade of flight hours, the Osprey had an accident rate about half that of the USMC aircraft fleet's average, and less than any rotorcraft in the USMC. Of course, it has the benefit of being younger than many of those aircraft, but it's apparent enough that it's not the death trap some seem to think it is.

-- They have to be happy. A LOT of people based their careers around keeping that program alive. Most Marines didn't care, as long as we FINALLY got some sort of replacement for the CH-53 and CH-46 (which, anecdotally, still have bullet holes from Vietnam in a few cases).

-- Even then, you'll note that the employment of the Osprey has been continually scaled back from what was originally promised.

[sir_pudding]

Originally Posted by Phoenix_Dragon

The Marines seem pretty happy with its reliability, too.

Meh. In eight years I only ever even saw one once, when Gen. Conway (CMC) visited camp Ramadi for one of his town hall meetings and was using one like a giant flying staff car.

[lwcamp]

Originally Posted by sir_pudding

Quetzalcoatlus on the other hand is generally estimated to have been about 200 lbs.

This paleontologist http://www.flickr.com/photos/markwitton/1386125619/ estimates 250 kg (550 lbs), and argues strongly against 200 lb quetzs. Just looking at the reconstruction at the top of the page of a full sized quetz next to a human has convinced me that they must be much more than 200 lbs (approximately human weight).

Luke

[sir_pudding]

Originally Posted by lwcamp

This paleontologist http://www.flickr.com/photos/markwitton/1386125619/ estimates 250 kg (550 lbs), and argues strongly against 200 lb quetzs. Just looking at the reconstruction at the top of the page of a full sized quetz next to a human has convinced me that they must be much more than 200 lbs (approximately human weight).

Yeah I just picked a middle estimate, I've seen arguments for as low as 150lb to as much as 600. Regardless they were probably both larger and more massive than humans (and yes they were probably "mostly gliders", but that doesn't mean they couldn't fly).

[Anthony]

Originally Posted by lwcamp

This paleontologist http://www.flickr.com/photos/markwitton/1386125619/ estimates 250 kg (550 lbs), and argues strongly against 200 lb quetzs.

Metabolic rate calculations pretty strongly argue for fairly low weight. If we assume it was able to take off from a flat surface and fly without an updraft, a 100 kg flier with fairly plausible aerodynamics requires a continuous power of around 600W (6 W/kg). That's in the range of extremely elite athletes, and not impossible for an animal. A 250 kg creature requires 2500W (10 W/kg), and given that metabolic scaling is generally lower than 1st order in mass, is grossly unlikely for an animal.

[Flyndaran]

Originally Posted by Anthony

Metabolic rate calculations pretty strongly argue for fairly low weight. If we assume it was able to take off from a flat surface and fly without an updraft, a 100 kg flier with fairly plausible aerodynamics requires a continuous power of around 600W (6 W/kg). That's in the range of extremely elite athletes, and not impossible for an animal. A 250 kg creature requires 2500W (10 W/kg), and given that metabolic scaling is generally lower than 1st order in mass, is grossly unlikely for an animal.

Metabolically, birds put all mammals to shame. I would expect similar performances for pterosaurs.

[lwcamp]

Originally Posted by Anthony

Metabolic rate calculations pretty strongly argue for fairly low weight. If we assume it was able to take off from a flat surface and fly without an updraft, a 100 kg flier with fairly plausible aerodynamics requires a continuous power of around 600W (6 W/kg). That's in the range of extremely elite athletes, and not impossible for an animal. A 250 kg creature requires 2500W (10 W/kg), and given that metabolic scaling is generally lower than 1st order in mass, is grossly unlikely for an animal.

A published study of pterosaur flap-gliding using Colin Pennycuick's Flight program (among other things, such as ecological arguments and bone analysis) indicates that "For Quetzalcoatlus, using the narrow planform of Chatterjee and Templin [19], the estimated best glide speed is 13.3 m/s, and the speed for minimum sink rate is 8.80 m/s. If Quetzalcoatlus was able to work under anaerobic power (see below) to climb out for one minute after launch, this minimum sink speed would provide over a half kilometre of range to reach an external source of lift. However, the situation is more favourable with heavier body masses because it provides substantially more total muscle power and much greater glide speed once the animal begins soaring. Under the broader wing shape of Witton [24], the expected best glide speed for Quetzalcoatlus is 24.9 m/s, and the minimum sink speed is 16.3 m/s. The minimum sink speed would therefore provide close to a kilometre of distance under a one-minute burst, minus distance lost to climbout altitude gain. However, most soaring animals today fly at their minimum sink speed when using thermal soaring and certain forms of shear lift [58], [66]. The maximum range speed may be a more reasonable estimate of the climbout velocity, especially for an animal trying to reach external lift sources. Assuming that Quetzalcoatlus carried mostly anaerobic muscle in its flight muscle mass, as predicted by Marden [23], and using the maximum power output of anaerobic avian muscle ([67] - a conservative estimate, as other diapsids produce more relative power from anaerobic muscle), the expected maximum range speed under the Witton [24] morphology is 48.3 m/s with a climbout altitude gain of 1 m/s. Taken alone, these figures indicate a one-minute burst range of 2.88 km. Of course, considerable time and power would be required to accelerate to the extremely high maximum range speed, but even with those considerations, the range to external lift under an aerobic burst would likely exceed 1.5 km."
http://www.plosone.org/article/info%...l.pone.0013982

Luke

[vicky_molokh]

Speaking of wings, by RAW they have a speed limit of 500mph. How realistic is it? Optimistic? Pessimistic?