[sonofhans]

For one thing, a 747 is only 250 feet long. So a 300-foot blade on top would trail significantly.

For another, the shuttle piggyback worked partly because of the shuttle’s aerodynamic profile. It’s designed to go straight forward into the wind. This means the 747 still handled well. A windmill blade, though, would present a very different cross section to the oncoming air, and seriously screw up the host’s aerodynamics.

So you could mask it and put fairings on it, and by the time you’ve done that 500 times you’ll wish you’d just built a special-purpose airplane to begin with.

[MadnessASAP]

The Boeing Dreamlifter is literally that. There's also the Airbus BelugaXL. Taking big cargo aircraft and putting bigger cargo fairings on it has been going on since the 60s.

None are capable of a 300' length, but they're also not far off. I'm not sure what Radias gameplan here is but I'm extremely doubtful they'll be able to spin up a bespoke airframe for this one market before Boeing/Airbus have built a FeverDreamlifter or BelugaXXL off an existing airframe.

Especially with A380s to be had rather on the cheap these days.

[sonofhans]

So I’m no expert, but I’m not sure I agree. For one thing, a Dreamlifter is 235 feet long. They’d have to add nearly 100 feet to that before it fit a 300-foot blade. I think that makes it a completely different airplane.

Also I wonder about density — turbine blades are really light, and this Radias seems not to have a huge wingspan. Perhaps it’s optimized specifically for long, low-density cargo. That’s not the market that Boeing or Airbus are going for with their craft.

[MadnessASAP]

I would love to deliver a TED talk on the costs and issues with developing new airframes vs adapting existing ones to new roles.

However I'll leave you with an analogy. If you were in the business of delivering mattresses, would you rather have a GMC cube van that is perhaps not aerodynamically optimal and has a weight capacity that exceeds your requirements but has parts available around the world and every mechanic and driver has seen before. Or would you rather develop a custom mattress delivery vehicle that no one knows what to do with, doesn't fit in normal parking lots and can only be maintained and driven by your own specially trained team of mattress delivery vehicle specialists. How many mattresses do you have to deliver in a year before that option makes sense? What happens when GMC sees this giant mattress delivery market and pulls the box off one of their larger pickups and attaches a mattress carrying unit?

[sio8ohPi]

External transport of wings has been done:

https://www.reddit.com/r/aviation/comments/wreq34/antonov_an...

[superb_dev]

That is much smaller and straighter compared to modern turbine blades