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The subject pretty much states my question, now I will provide a bit of background.

A family member, who lived on the west coast of Florida Manasota Key, collected tens of thousands of fossilized sharks teeth between the mid-1940s and the late 1970s. I have now become involved in deciding what to do with these sharks teeth. Here is one of the multitude of pictures available showing samples of these types of sharks teeth:

Enter image description here

The vast majority of this collection ranges in size between a dime and a quarter and likely has the same level of hardness.

If you've visited one of the beaches in this part of Florida in the last 25+ years, you probably know that finding these treasures is no longer as easy as it used to be. When I was a kid (late 1970s), I could usually come up with 10+ teeth in about a 2 hours stretch. However, by the time my kids were of the age where this would be of interest (early 2000s), we were lucky if we found one a day.

What I'd like to do is return these teeth to the area just off shore of this beach thus giving future searchers a better chance of "re-finding" them.

Let's assume for the purposes of this question that the airplane involved would be a Cessna 172S. What would be a good way of doing such a drop without harming the aircraft itself?

I assume just dropping them out the window risks blow back that could damage the aluminum fuselage or tail assembly.

A couple of notes:

  • This is NOT a question about the legality of dropping items from an airplane in the United States. I am well versed with 14 CFR § 91.15 - Dropping objects, which states:

No pilot in command of a civil aircraft may allow any object to be dropped from that aircraft in flight that creates a hazard to persons or property. However, this section does not prohibit the dropping of any object if reasonable precautions are taken to avoid injury or damage to persons or property.

  • I am not interested in a solution harmful to the environment. Thus dropping them in taped boxes or rolled up newspaper would not be warranted, because that would be littering.

  • I'm certainly aware that renting a boat and dropping them off the side would be an alternative. That said, for the purposes of this question, I am specifically asking how to achieve this using a Cessna 172 (or similar) high wing GA airplane.

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  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$ – Federico Jul 23 at 5:19

10 Answers 10

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Funeral homes sell gum bags for ashes. They dissolve in the ocean, releasing the ashes. You could make satchels and drop them in bundles with the teeth wrapped in kelp.

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  • $\begingroup$ I'm leaning toward this answer. Have you actually done this? Also, are the bags biodegradable/environmentally neutral? $\endgroup$ – bclarkreston Jul 18 at 19:46
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    $\begingroup$ @bclarkreston I think you’re going to struggle to find anyone who’s actually dropped fossilised sharks teeth out a Cessna 172 in cremation bags. $\endgroup$ – Tim Jul 18 at 23:27
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    $\begingroup$ Ah...let me clarify my question. I meant to ask if the person answering the question had actually used gum bags to drop anything from an airplane ;-) $\endgroup$ – bclarkreston Jul 18 at 23:30
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    $\begingroup$ Needn't be special gum bags. They could be vitrified in anything biodegradable. What comes to mind is "ice". $\endgroup$ – Harper Jul 19 at 15:20
  • $\begingroup$ @Harper ice sounds like a perfect answer $\endgroup$ – Notts90 Jul 19 at 17:15
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Spitballing an idea... Not sure of the legality or practicality of this, but it's an idea that came to mind.

Using a piece of 2-3" diameter PVC pipe (sized as necessary to clear the largest tooth), attach (very securely - using the appropriate PVC glue and, possibly adding some screws) it to one edge of a sturdy (heavy plastic) box. Add some eye bolts to the sides of the box.

When you reach the drop zone, attach ropes (with swivel connectors, like on a dog's leash) to the eye bolts, slide the pipe out the window/door so that it hangs into the air stream, but below the empennage, slowly pour the teeth into the other end of the box and let them slide down to the spout and out of the plane.

The pipe will guide them down far enough to clear the bottom of the plane and give you controlled output. The ropes (attached to something inside the plane prior to take off) will ensure the box doesn't go sailing out of the plane.

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    $\begingroup$ Great idea but I'm not sure a pipe that would fit in plane would be long enough to ensure that flat objects like that might not generate enough lift to fly up and hit tail- $\endgroup$ – quiet flyer Jul 17 at 19:09
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    $\begingroup$ That's a valid thought I hadn't considered. It might be possible to heat the tube (I'm thinking a propane torch) then flatten the end so that the teeth come out vertically. That, of course, leads to the possibility of the teeth jamming inside the tube instead of slipping down smoothly. $\endgroup$ – FreeMan Jul 17 at 19:15
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A nonprofit in Kenya is doing something remarkably similar (link shows the distribution of pellets formed of tree seeds and fertiliser to degraded areas to encourage reforestation).

One short observation from the video suggests that the vacuum effect on the end of a flexible pipe hung out of the window of a light aircraft is sufficient to draw small objects from inside the cabin. Shark teeth might be too dense but it's worth a try.

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  • $\begingroup$ Wow...that is similar! The only difference might be that if these are seed pods they are likely quite a bit softer than sharks teeth would be. $\endgroup$ – bclarkreston Jul 18 at 17:31
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    $\begingroup$ What is the airspeed velocity of an unladen shark's tooth? $\endgroup$ – Harper Jul 19 at 15:18
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    $\begingroup$ @Harper African or European? $\endgroup$ – Michael Richardson Jul 19 at 22:01
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    $\begingroup$ @MichaelRichardson African, obviously, that's where Kenya is located. ;) $\endgroup$ – FreeMan Jul 22 at 12:40
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Rig a curved PVC tube running from window to behind and below tail and have passenger pour teeth through a big funnel. You may need a fairly large diameter pipe because with this version of pipe idea, the slope of the pipe is small, making it easier for teeth to jam. Maybe the end of the pipe will even drag on ground during taxi and takeoff run or at least when you rotate for takeoff, which should be ok as long as the pipe has some flex, as the pipe doesn't have to survive multiple uses. Check what pipe does when you put the aircraft tail tiedown ring on the ground before actually flying with this idea. Also check what happens when you turn while taxiing. Operating from a grass strip would help.

Calculate CG carefully!

Maybe even bring a pressurizable (pump-up) container of water to blast teeth out if get stuck, or something like a toilet snake, or just do sufficient tests on ground ensure won't get stuck. You may want to drop teeth in steep climb to make pipe steeper.

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    $\begingroup$ Decided to make pipe idea a separate answer $\endgroup$ – quiet flyer Jul 17 at 20:07
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You can crack the door on a Cessna 150 or 172 while in flight, probably can most other high wing aircraft. So just crack the door, put a PVC pipe out the door far enough so it is out in the slipstream, and pour your shark's teeth into the pipe. Further away from the tail and easier to manipulate than out the window.

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    $\begingroup$ Oh an keep your seatbelt on if you're going to open the door. You're welcome $\endgroup$ – zundi Jul 18 at 23:50
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    $\begingroup$ You can steer a Cessna by opening and closing the doors alternately. Demonstrated to me by my instructor many decades ago. $\endgroup$ – MikeY Jul 19 at 14:14
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    $\begingroup$ I think the concern is the flat shape of teeth may make them follow very unpredictable trajectories including climbing upward so it might take a very long pipe to do that- as noted in other similar comment to other similar idea. $\endgroup$ – quiet flyer Jul 19 at 16:40
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Out the window should work fine, assuming they're as dense as a typical fossil. The "blowback" hazard is with low-density or fine particulate materials such as the human ashes that you hear all the horror stories about.

You can fly at a lower airspeed to further improve the clearance from the empennage.

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The common technique for scattering ashes is to put them in a small cloth bag, under the wing and well away from the fuselage. Tie the bag with a slipknot, and open it by tugging on the other end of a rope run under the wing to a cockpit window.

You can further avoid risk to the airplane body by paying careful attention to the prevailing wind, and making sure the drop happens on the leeward side of the plane while crabbing. This should make the pieces move away from the plane very quickly as soon as the bag is opened.

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  • $\begingroup$ I think they might fly up and hit wing. Maybe cover wing behind bag with adhesive film of some kind to protect paint. $\endgroup$ – quiet flyer Jul 17 at 16:34
  • $\begingroup$ Wait, are you suggesting that the prevailing wind direction makes any difference? You said "crabbing", did you really mean a simple "crab" like we do all the time on a cross-country flight, and during a non-slipping style of crosswind landing up the point where we "kick out the crab", or did you mean a true cross-controlled slip to put a sideways flow over the aircraft, in which case the meteorological wind direction would be completely irrelevant? Sorry, but I have no choice but to downvote until clarified! $\endgroup$ – quiet flyer Jul 17 at 19:06
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    $\begingroup$ @quietflyer seems pretty clear to me what he is saying, aren't crabbing and slipping two different maneuvers? The point of crabbing in his answer is that you want the wind to be moving perpendicular to the fuselage so that the objects are more likely to blow leeward. $\endgroup$ – bclarkreston Jul 18 at 15:53
  • $\begingroup$ @bclarkreston - that is not crabbing. It is a some form of a slip, or possibly a wings-level skidding turn which arguably ought to fall within the larger aerodynamic category of sideslip, i.e. sideways flow. Anyway what you are describing is definitely not crabbing. Could be the basis of anothet ASE question - "what is crabbing, in the aviation context, and does a yaw string (located outside of any propwash) blow straight or sideways?" $\endgroup$ – quiet flyer Jul 19 at 15:45
  • $\begingroup$ @quietflyer downvoting based on a small thing like that when the general idea is sound, seems quite petty to me, especially when you have several heavily downvoted answers. $\endgroup$ – Notts90 Jul 20 at 18:15
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It sounds like you're concerned that the teeth would fly around uncontrollably after being released and possibly damage the aircraft. Try changing their aerodynamic properties. The answer that mentioned marbles got me thinking that if you rolled the shark's teeth in cookie dough then the teeth would fall through the air in a more predictable fashion. I like the idea of a little ball of biodegradable cookie dough, with a crunchy shark's tooth center, falling through the sky. Then those ideas about using a pipe or just tossing out the window would be more viable. (Rolling the dough balls in powdered sugar to facilitate sliding down a pipe is optional.)

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    $\begingroup$ 10000 teeth times a teaspoon of dough each is already 50kg of cookie dough. $\endgroup$ – David Richerby Jul 18 at 22:08
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    $\begingroup$ @DavidRicherby. So that's a yes? :) $\endgroup$ – Mad Physicist Jul 18 at 23:06
  • $\begingroup$ Oh, sure, ... and then all sorts of creatures, including children, will try to eat the cookie dough! $\endgroup$ – Carl Witthoft Jul 19 at 14:00
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    $\begingroup$ I think you're just looking for an excuse to eat all the extra cookie dough :) $\endgroup$ – Harper Jul 19 at 15:24
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If they were marbles of the same weight, I think you could be sure would not hit tail if just poured out window, but maybe not with those teeth. Here's one solution: remove brace from side window to permit full opening. Put teeth in bag. (Optional: fill extra space in bag with sand to make heavier). Have top of bag tied shut with flaps that will open when a string pulls out a pin. Have bottom of bag securely tied to strong long rope. Throw bag out window, string comes tight first, opens top of bag, then rope comes tight and holds bag securely upside down. Or just do it with one rope, you just have a loose "bight" threaded through the rubber band that holds the bag closed, as is done with parachute shroud lines. (You could even buy a hang glider parachute deployment bag.)

Anyway after deployment the empty bag trails harmlessly way behind the tail till landing.

Better yet remove door and push bag out door. How big a bag would it take to contain all the teeth anyway?

Simpler- a strong-ish plastic bag like a trash compactor bag or heavy garbage bag. Remove door and passenger seat to accomodate huge bag with thousands of teeth. Bag is filled with teeth, bunched up on top, wrapped round with twine, then a long heavy rope is tightly tied around "bunched" point. Leave lots of excess bag material on top above "bunch" point so bag cannot slip out through twine and rope. Bag is tied to secure strong fuselage member or landing gear. To drop, do an extreme slip, or push bag out with broom or similar. Bag falls to end of rope, bottom rips open, teeth fall, empty bag trails well behind tail. (You'll use a rather long rope.)

Do tests on ground out of second-story window with same kind of bag to make sure it will consistently rip open when reaches end of rope and doesn't pull loose through rope and twine. Maybe using a bag full of same weight of gravel or sand, so you don't have to pick up all the teeth again. Of course the teeth will do a better job of ripping the bag than gravel or sand will. Make sure the bag is strong enough that the teeth won't rip the bag in the plane, and be sure the plane has an interior such that loose objects can't migrate to tailcone. Tie bag securely into place before takeoff with rope or strap that you can easily undo. Maybe better to leave passenger seat in place after all to facilitate buckling bag into place; also it will put bag in better postion for you to shove it out the missing door with one hand and avoid issue with bag clearing door sill. Make sure the bag cannot interfere with controls in any way!

A bag with a ripstop kind of "weave" (texture) would help stop minor tears and punctures from propagating before the drop, if such a thing exists in a disposable bag. You may end up needing to double-bag the teeth- do some experimenting.

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  • $\begingroup$ I see another answer had similar idea, but I would rig a long curved pipe basically parallelling fuselage before takeoff. $\endgroup$ – quiet flyer Jul 17 at 16:18
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    $\begingroup$ I've seen a number of questions asking about attaching a GoPro type camera to the outside of a plane. The general consensus is that is a "modification" requiring approval and paperwork. I would think attaching a pipe prior to flight would fall into that category as well. Who knows, maybe my "temporary pipe out the window" suggestion would cause CAA trouble, too. $\endgroup$ – FreeMan Jul 17 at 16:36
  • $\begingroup$ Well, good point, but maybe he can operate from a secluded airstrip where no one will care. Sure never stopped me from attaching Go Pros! $\endgroup$ – quiet flyer Jul 17 at 16:41
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    $\begingroup$ I'm not sure recommending "skirt the law and risk a potential FAA violation" is something we want to be seen doing at ASE... If OP chooses to ignore warnings and do it anyway, that's on him. (Again, don't know if that's legal or not.) $\endgroup$ – FreeMan Jul 17 at 18:08
  • $\begingroup$ (comments were intended for pipe answer which is now a separate answer) $\endgroup$ – quiet flyer Jul 17 at 20:16
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Inspired by another answer What would be the safest way to drop thousands of small, hard objects from a typical, high wing, GA airplane? (and now I also notice the comment suggesting to freeze the teeth in ice) : make a giant shark's tooth cookie! Mix dough and teeth together in barrel, let harden, cut away barrel, and take mister sharktoothcookie for a one-way flight in a plane with door removed.

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protected by Community Jul 19 at 11:19

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