They will conduct an experiment to see if Blattella germanica can reproduce on a conveyor belt.
Yes, I endeavored to explain it on a level Adam could understand.
Perhaps I erred.
Dang, I missed it! Now I’ll have to look for reruns.
Was the Straight Dope mentioned at all? (Though it’s been debated lots of other places too.)
The web in general was mentioned as well as a “fan site”.
May I offer this chance to suck up to a Mod by sending you a DVD of the program?
So, in other words, if the pilot holds the brakes on, then revs the engine to full power, the plane won’t move forward at all but will rise off the ground straight up? A moment’s thought should tell you how wrong that is. If it were true, every plane could do a vertical takeoff, and there’d be no need for runways (ok, except for landings, I guess).
the aircraft is on the treadmill, and as it moves to 25mph (let’s say, west), the treadmill matches that speed to the east. the wheels will be spinning as if the plane were travelling at 50mph, but the plane is still travelling at 25mph to the west, and the treadmill is still moving at 25mph to the east. (see, its speed is determined by the prop, which does not interact in any direct (relevant) way with the ground. Remember, some airplanes take off on skis, with no wheels at all.) if this airplane’s T.O. speed < 25mph, it’ll still get off the ground. The detail to remember is that the treadmill doesn’t match the rotation speed of the wheels… it matches the forward velocity of the airframe, which will still be moving.
S^G
(I know this has been done to death many times, but since I didn’t have my membership yet then, I felt I needed to get my input out there… I apologize for that)
Don’t scoff too much. Take a look at the Boeing YC-14 and Antonov An-72. Both of those planes have turbofan engines mounted ahead of and above the wing, with the jet exhaust flowing directly over the wing. It’s not enough to take off from a dead stop, but it does shorten the takeoff roll.
Indeed, some take off from water, which may be flowing one way or another.
I can’t tell which side of the argu…discussion you are on.
I’m not sure what the argument is. I thought it was that the conveyor belt would keep the airplane still in relation to a stationary observer and it would get no lift and could not take off.
That has a familiar ring to it… :dubious:
The point, though, is that (in the real world, at least) the conveyor is incapable of keeping the plane still in relation to a stationary observer. That the conveyor is going backwards at 25pmh does not prevent the plane from nevertheless moving forward (relative to a stationary observer) at 25mph (and taking off, if 25mph is its takeoff speed). The only effect of the conveyor, as Satellite^Guy pointed out, is that the plane’s wheels will be spinning at 50mph (25mph relative to the conveyor, plus 25mph relative to the stationary observer).
My point was, the plane didn’t have to have any forward momentum to take off if there is sufficient air going over the wings. Presumably, you could set a (hypothetical) super-powerful fan to push the air over the wings with the plane’s engine turned off, and it would rise. It would have to, if there’s sufficient lift, velocity or no. That’s how airplane wings work.
The show does have its own message board at discovery.com that Adam and Jamie participate in occasionally, so that’s probably the fan site they referred to.
But what did that poor Volvo do to deserve being filled with hard foam? What sort of stupid time filler was that?
Perhaps in some sort of tunnel-shaped room.
According to Discovery’s site, the episode will run again on Saturday, March 1 at 9:00 P.M. (I assume Eastern time) and again at 1:00 A.M. on March 2.
Nothing hypothetical about it. That’s why small planes are either kept in a hangar or literally tied down to the ground. If the take-off speed is, say, 35 mph then a 35 mph wind blowing over airplane’s wings WILL launch it. I have seen small Cessnas that were only loosely tied down hovering during storms. In one case, the ropes broke and a Cessna 170 went airborne, then cartwheeled when the gust dropped.
For generating wind? Now there’s an idea…
Nay, 'twas The Master Himself: http://www.straightdope.com/classics/a1_262.html
Thanks. (I’m also hoping to see it sooner.)
Ok, I hope this isn’t considered a hijack, but it’s about one of the “non-plane-on-a-conveyor-belt” parts of the episode: cockroaches surviving radiation.
First off: it was certainly cool to watch the Junior-busters take a trip to a high-radiation lab. I found the “Line Of DEATH!” bit amusing. 
Second off: they gave us the rad exposures they exposed the bugs to, but how do those compare to the radiation output of a nuclear bomb? I tried some googling, but could only find sites that were either for radiation detectors, or ones that were so full of math that I couldn’t follow (or figure whether there was even enough info provided to work out an answer). What would be the exposure from, say, a 1 megaton bomb at a range sufficiently far away to not be toasted by the heat (One mile? Five miles? Ten?), but with no radiation protection? And I suppose we have to consider both the inital blast itself, plus the radiation produced by the fallout.
Overall, was a pretty cool episode (well, leaving out the frozen shaving cream “prank”).
FWIW, my husband and I finally figured out why we couldn’t agree on this, and I think he convinced me.
See, I was assuming that the treadmill would keep the plane stationary relative to the air around it.
He was assuming that I knew that the propeller would pull it forward regardless of the treadmill, since the power for the plane doesn’t come from the wheels - they’re just free-spinning.
Once he backed up a step (with Jamie’s help) and explained to me why the backwards-moving treadmill in contact with the wheels was irrelevant in the forward motion of the plane, I could see why the plane could take off.
He also agreed with me that in the hypothetical case that the plane’s wing is actually stationary relative to the air, it couldn’t take off.
(For the record, I’m an English major, he’s a mechanical engineer.)