How to Troubleshoot your AR Drone after a crash (1.0 and 2.0)…….

Sooner or later (probably sooner) you are going to have a nice little wreck with your AR Drone. Maybe you hit a wall too hard, hit the ceiling, smacked a tree, or sucked in a twig. Wrecks, crashes, and other emergency stops are par for the course with the AR Drones.

NOTE: This is an older “legacy” article and not updated – if you think it’s time to upgrade to a more capable quadcopter/drone, check out our list of current recommendations.

In many situations, you just need to place the AR Drone back on a flat surface and start over. While this may work most of the time, other times the drone won’t level properly, one motor might not spin up, or some other problem will come up. That’s when you need to try some alternative solutions.

The tips below will have (1.0) for the original Parrot AR Drone or (2.0) for the current Parrot AR Drone 2.0. Tips that cover both the AR Drone 1.0 and AR Drone 2.0 will have (1.0 / 2.0).

AE lock, AF lock, FE lock, LCD live view mode, RGB primary color filter, audio recording, auto power save, camera orientation detection, depth-of-field preview button, digital image rotation.

1. Always do a Flat Trim / Calibrate.
(1.0) Before every flight, crash or not, always do a Flat Trim, then, once you launch, let the AR Drone hover for about 10 seconds before flying. If all is well at this point, you should be good to go.

(2.0) Before every flight, crash or not, always calibrate the AR Drone 2.0. After connecting the battery place the AR Drone 2.0 on as level of a surface you can find. On your flight app find and click “Calibrate” before taking off. Then take off and allow the AR Drone 2.0 to hover, once a nice hover has started click the “calibrate” button again and allow the AR Drone 2.0 to spin 360 degrees.

Doing the above allows the AR Drones gyros and sensors to reset and allow a good flight.

2. Reset after a crash.
(1.0) If you are using Parrot’s FreeFlight app, then you will need to press the reset button on the bottom of the AR Drone. You will need an “in-field drone reset tool” (a toothpick for example). If you are using AR Drone Flight for Android, the Emergency button on the top will become a Reset button when the AR Drone is not flying. Pressing the RESET will recalibrate the sensors and will almost always get you back flying again.

(2.0) Normally it is not necessary to push the rest button after a crash, just calibrate the AR Drone 2.0 as told in tip 1 (2.0) above. But if the AR Drone 2.0 still has issues, the reset button can be found under the battery through a small hole in the battery tray. The button is a fair distance down inside, but with steady hands you will be able to push it with the “in-field drone reset tool”.

Note: We recommend a nonconductive tool (toothpick or small plastic rod) for the “in-field drone reset tool”. Accidentally shorting out the AR Drones circuit board by using something like a paper clip could cause damage that will require the circuit boards replacement

3. One or more motors won’t spin up.
(1.0 / 2.0) This is a fairly rare phenomenon but it can happen in a flight just after a crash. You have to be fast on this because without all the motors spinning on launch, the AR Drone will only make it about a foot or two into the air and do a nasty backflip (hopefully not into something). If pressing the reset button doesn’t solve this one, first check the motor gears for any broken or grit / dirt binding them up. Also check that there doesn’t seem to be any wobble in the prop shaft by unplugging the battery and spinning the propellers a few times by hand (see tip 5 if you have a bent shaft). Follow the instructions in tip 2 above and hopefully that should put you back into the air. After trying all this and the motor still does not turn, you might have blown the motor, ESC, or the motherboard.

4. All motors are spinning but the AR Drone flips over.
(1.0 / 2.0) See tips 1 and 2; also check the motor gears for any broken or grit / dirt binding them up. Then check that there doesn’t seem to be any wobble in the prop shaft by unplugging the battery and spinning the propellers a few times by hand (see tip 5 if you have a bent shaft).
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5. AR Drone takes off but seems to be unstable and somewhat noisier than before.

(1.0 / 2.0) You may notice the AR Drone wobbling a bit or it will drift and not hold a stable hover. After a number of crashes, the propeller drive shafts could be bent or the propellers are damaged / warped. These problems can be determined in a couple of ways. One is to just spin the props by hand and at eye level look to see if any wobble in the prop shaft is present. Inspect each propeller for cracks or other damage (if you find any cracks or chips in the propellers DO NOT FLY with them).

If you are 100% certain there is no damage to the propellers you can fly the AR Drone at eye level and carefully watch each propeller. The one(s) that are off-balance because of a bent drive shaft or warped propellers should be evident as the two blades of each propeller will look like they are at two different heights. It is highly recommended that you have a helper to do this, one to fly while the other watches the propellers and wear safety glasses!!!

To determine if the drive shafts are bent remove them from the AR Drone and roll them on a hard flat surface to determine where the bend is. You could straighten them by putting the bend facing up on an anvil with a hole in it (place the bend over the hole) and tapping it down with a small hammer. But once bent you will never be able to get them perfectly right. Replace them with either stock versions or any of the aftermarket upgraded ones (titanium versions are our favorite) for the best results.

Instability from the propellers being warped (some replacement propellers will be warped out of the package) can be fixed as well. We recommend doing the following to the AR Drone propellers from the start anyway. This will not only make the flight more stable but also cure many problems as like; Vibration in your video recordings, drifting around while hovering, losing altitude when coming to a stop from forward flight, wont climb to a higher altitude, bad flips (2.0), or acts like the motors are cutting out and dropping a few inches ever few seconds.

Note: The below procedure came from DroneBonerStallone, his original post can be found here Fix Your Props.

To start you are going to need a few “tools”. Find a decent 1980’s type hair dryer, the kind that blows your hair dry. Two 1 1/2″ (38 mm) metal tubes about 3″ (76 mm) long. A bunch of reusable or regular zip ties (the reusable ones are best as you can reuse them, but regular ones work just as well). A flat piece of metal strip 1″ X 12″ X 1/8″ ( 25 mm X 305 mm X 3 mm). A few modeler clamps or cloths pins (the wood with spring type).

Remove the propellers from the AR Drone (important, note where each one came from. some rotate clockwise and the others anti-clockwise) Use a piece of colored tape on two that turn in the same direction. Put a piece of tape on the center of the propeller and a piece on the arm of the AR Drone the propeller came from. When removing the “Jesus” clip from the propeller shaft be careful, they have a tendency to fly away…..that’s when you say Jesus Christ, where did that go. And why they are called Jesus Clips.
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First we need to make sure the propeller still has the airfoil shape it needs to create lift. Looking towards the tip of the propeller at the end it should have a nice curve to it.

The picture on the left shows what the propeller should look like by looking at it from the blade tip.

If the tip looks flat then a little corrective action will need to be done. The two metal tubes, zip ties, and 1980’s hair dryer will be needed. Attach the two tubes to the propeller as shown in the picture to the right. Then using the high setting on the hair dryer slowly heat the tips of the blade, let it cool to room temp and do it again. You may have to do it a few times to get the plastic to relax in the curved shape. Make sure to propellers have cooled before removing the zip ties.

We Also need to make sure the propeller is flat along the leading edges. Looking at the leading edges of the propeller it should be flat along its entire length (the tip curve will be slightly above the leading edge towards the tips). See the picture below.

If the leading edges of the propellers are not flat another easy fix can be done. Get the cloths pins and flat metal strip, clamp the propeller to the metal strip as shown below (we recommend a metal strip as it helps in the heating process, a ruler can be used though). Only clamp on the leading edge, if you clamp too far in you will have to redo the tip curve. Using the high setting on the hair dryer slowly heat the blades, let them cool to room temp and do it again. You may have to do it a few times to get the plastic to relax and keep the leading edges flat. Once again, let the propeller cool before removing the clamps.

Now the propellers should have the right tip curve and be flat along the leading edges, but we are not done yet. Balancing the propellers is next. There are a number of ways to do this, but most do not balance the main gear and propellers together. We do, and this is how. You are going to need a set of parallel and perfectly level “rails” high enough to allow the propeller to freely “spin”. Some way to add weight to the light blade, tape can be used. As you do each blade temporarily remove the marking tape added when you took them off the AR Drone.

Assemble the main gear, propeller shaft, and propeller as shown in this picture to the left. Make sure the gear you use stays with the propeller it was balanced with, we are balancing the assembly and they will be matched once done.

Now we need to set up the balance stand. This is the “rails” mentioned above. A block of wood and two metal plates can be used to make one similar to the one in the pictures. The top edges of the “rail” must be perfectly level. A spirit level along the top of both edges as well as across the pair will let you know if your level.

To balance place the propeller assembly on top of the balance stand and allow the assembly to “spin” around (see picture to the right). The side that is heaviest will naturally fall low. Once you know which side is lightest you can add a small piece of tape on the under side of that blade tip.

Add a long strip of tape and trim off small amounts at a time until you get the right amount. Once the propeller sits level on the stand and does not favor one side or the other your almost done.

You could add weight with paint, clear finger-nail polish works well. Add a little paint at a time, once balanced let it dry and check the balance again.

Next you will “stand” the propeller vertical and see if it wants to fall to one side or the other. Do this with one blade high, then the other blade high. If it just stays where you put it you are done.

If the propeller tip tends to always fall in one direction you need to add weight to one of the gear spokes, if the tip falls left add to the right gear spoke, or the opposite if the tip fell right. Tape can work for this, but it might be easier to use paint.

Once you have balanced all the propellers with their gears put them back onto the AR Drone (in the correct location).

6. Constant Ultra Sound / Video Alerts.

(1.0 / 2.0) If everything was working fine before, but after a crash you are now getting Ultra Sound or video alert messages. You may need new electronics. But before you go out and spend money on any parts there are a few things you could try first.

Warning: If you are not comfortable taking apart the AR Drone (1.0 or 2.0) then get to your hobby store and let them diagnose and fix it.

Take the bottom plate off the AR Drone to expose the circuit boards inside. Then check that all the cables, wires, and connectors are tight. By just making sure everything inside is still together will solve most of this type of problem.

Also check that everything is clean and dry, canned air will clean out most dust. While the bottom is off do a short “test flight” indoors. If all the alerts are gone then reassemble the AR Drone. and enjoy the money you saved from nor buying a part you did not need.

7. All four motor LED’s do not turn green.

(1.0 / 2.0) See tip 6, same type of problem normally. But sometimes the ESC’s blow out. If there is a small crater on the case of the FET’s your going to have to replace the ESC. See the picture on the right, the part that is in the lower right has blown a FET. That means replacing the ESC / motor assembly.

8. Other Tips

If you want to avoid a lot of the crash problems, be sure to read this Droneflyers.com article on shock absorbing landing gear.

If you have additional troubleshooting tips, please let us know. We also have a continuation and Q/A discussion of this article at our forums – please join and ask your questions. Here is the link to the Droneflyers Forum Discussion of this article.

NOTE: This is an older “legacy” article and not updated – if you think it’s time to upgrade to a more capable quadcopter/drone, check out our list of current recommendations.

A reamer is a type of rotary cutting tool used in metalworking. Precision reamers are designed to enlarge the size of a previously formed hole by a small amount but with a high degree of accuracy to leave smooth sides. There are also non-precision reamers which are used for more basic enlargement of holes or for removing burrs. The process of enlarging the hole is called reaming. There are many different types of reamer and they may be designed for use as a hand tool or in a machine tool, such as a milling machine or drill press.

Construction[edit]

A typical reamer consists of a set of parallel straight or helical cutting edges along the length of a cylindrical body. Each cutting edge is ground at a slight angle and with a slight undercut below the cutting edge. Reamers must combine both hardness in the cutting edges, for long life, and toughness, so that the tool does not fail under the normal forces of use. They should only be used to remove small amounts of material. This ensures a long life for the reamer and a superior finish to the hole.

The spiral may be clockwise or counter-clockwise depending on usage. For example, a tapered hand reamer with a clockwise spiral will tend to self feed as it is used, possibly leading to a wedging action and consequent breakage. A counter-clockwise spiral is therefore preferred even though the reamer is still turned in the clockwise direction.

For production machine tools, the shank type is usually one of the following: a standard taper (such as Morse or Brown & Sharpe), a straight round shank to be held by a collet, or a straight round shank with a flat for a set screw, to be held by a solid toolholder. For hand tools, the shank end is usually a square drive, intended for use with the same type of wrench used to turn a tap for the cutting of screw threads.

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Reaming versus drilling to size[edit]

The geometry of a hole drilled in metal by a twist drill may not be accurate enough (close enough to a true cylinder of a certain precise diameter) and may not have the required smooth surface finish for certain engineering applications. Although modern twist drills can perform excellently in many cases—usually producing sufficiently accurate holes for most applications—sometimes the stringency of the requirements for the hole's geometry and finish necessitate two operations: a drilling to slightly undersize, followed by reaming with a reamer. The planned difference between the drill diameter and the reamer diameter is called an allowance. (It allows for the removal of a certain small amount of material.) The allowance should be < 0.2 mm (.008 in) for soft materials and < 0.13 mm (.005 in) for hard materials. Larger allowances can damage the reamer. The drilled hole should not be enlarged by more than 5% of the drilled diameter. Drilling followed by reaming generally produces hole geometry and finish that is as close to theoretical perfection as possible. (The other methods of hole creation that approach nearest to perfection under certain conditions are boring [especially single-point boring] and internal cylindrical grinding.)

Types[edit]

Chucking Reamer[edit]

Chucking reamers, or machine reamers, are the most common type of reamer used in lathes, drill presses, and screw machines that provide a smooth finish to the hole. They come in a variety of flutes and cuts (e.g. right hand cut, left hand spiral, straight flute) as well as different shank types. Chucking reamers can be manufactured with a straight shank or morse taper shank. ^[2]

Adjustable hand reamer[edit]

An adjustable hand reamer can cover a small range of sizes. They are generally referenced by a letter which equates to a size range. The disposable blades slide along a tapered groove. The act of tightening and loosening the restraining nuts at each end varies the size that may be cut. The absence of any spiral in the flutes restricts them to light usage (minimal material removal per setting) as they have a tendency to chatter. They are also restricted to usage in unbroken holes. If a hole has an axial split along it, such as a split bush or a clamping hole, each straight tooth will in turn drop into the gap causing the other teeth to retract from their cutting position. This also gives rise to chatter marks and defeats the purpose of using the reamer to size a hole.

Straight reamer[edit]

A straight reamer is used to make only a minor enlargement to a hole. The entry end of the reamer will have a slight taper, the length of which will depend on its type. This produces a self centering action as it enters the raw hole. The larger proportion of the length will be of a constant diameter.

Reamed holes are used to create holes of precise circularity and size, for example with tolerances of -0/+0.02 mm(.0008') This will allow the force fitting of locating dowel pins, which need not be otherwise retained in the body holding them. Other holes, reamed slightly larger in other parts, will fit these pins accurately, but not so tightly as to make disassembly difficult. This type of alignment is common in the joining of split crankcase halves such as are used in motorcycle motors and boxer type engines. After joining the halves, the assembled case may then be line bored (using what is in effect a large diameter reamer), and then disassembled for placement of bearings and other parts. The use of reamed dowel holes is typical in any machine design, where any two locating parts have to be located and mated accurately to one another - typically as indicated above, to within 0.02 mm or less than .001'.

Another use of reamed holes is to receive a specialized bolt that has an unthreaded shoulder - also called a shoulder bolt. This type of bolt is commonly used to replace hot peened rivets during the seismic retrofit of structures.

Hand reamer[edit]

A hand reamer has a longer taper or lead in at the front than a machine reamer. This is to compensate for the difficulty of starting a hole by hand power alone. It also allows the reamer to start straight and reduce the risk of breakage. The flutes may be straight or spiral.

Machine reamer[edit]

A machine reamer only has a very slight lead in. Because the reamer and work piece are pre-aligned by the machine there is no risk of it wandering off course. In addition the constant cutting force that can be applied by the machine ensures that it starts cutting immediately. Spiral flutes have the advantage of clearing the swarf automatically but are also available with straight flutes as the amount of swarf generated during a reaming operation should be very small.

Rose reamer[edit]

A rose reamer has no relief on the periphery and is offset by a front taper to prevent binding. They are secondarily used as softing reamers.

Shell reamer[edit]

Shell reamers are designed for reaming bearing and other similar items. They are fluted almost their whole length.

Tapered reamer[edit]

A precision tapered reamer is used to make a tapered hole to later receive a tapered pin.A taper pin is a self tightening device due to the shallow angle of the taper. They may be driven into the tapered hole such that removal can only be done with a hammer and punch. They are sized by a number sequence (for example, a No.4 reamer would use No.4 taper pins).Such precision joints are used in aircraft assembly and are frequently used to join the two or more wing sections used in a sailplane. These may be re-reamed one or more times during the aircraft's useful life, with an appropriately oversized pin replacing the previous pin.

Morse taper reamer[edit]

A morse taper reamer is used manually to finish morse taper sleeves. These sleeves are a tool used to hold machine cutting tools or holders in the spindles of machines such as a drill or milling machine. The reamer shown is a finishing reamer. A roughing reamer would have serrations along the flutes to break up the thicker chips produced by the heavier cutting action used for it.

Combination reamer[edit]

A combination reamer has two or more cutting surfaces. The combination reamer is precision ground into a pattern that resembles the part’s multiple internal diameters. The advantage of using a combination reamer is to reduce the number of turret operations, while more precisely holding depths, internal diameters and concentricity. Combination reamers are mostly used in screw machines or second-operation lathes, not with Computer Numerical Control (CNC) machines because G-code can be easily generated to profile internal diameters.

Combination reamers can be made out of cobalt, carbide, or high speed steel tooling. When using combination reamers to ream large internal diameters made out of material with lower surface feet per minute, carbide tips can be brazed onto a configured drill blank to build the reamer. Carbide requires additional care because it is very brittle and will chip if chatter occurs. It is common to use a drill bit or combination drill to remove the bulk of material to reduce wear, or the risk of the part pulling off on the combination reamer.

Tapered reamer (non-precision)[edit]

A tapered reamer may be used for cleaning burrs from a drilled hole, or to enlarge a hole. The body of the tool tapers to a point. This type of reamer consists of a body which, typically, is up to 1/2 inch in diameter, with a rod cross piece at the large end acting to form a handle. It is especially useful for working softer metals such as aluminum, copper, and mild steel. Another name for it is 'maintenance reamer', referring to its use in the miscellaneous deburring and enlarging tasks often found in MRO work. A similar tool can be seen on select Swiss Army knives, such as the electrician model, to be used on conduit.

Process[edit]

To achieve highly accurate and consistent diameters with a reamer, one must consider process variables that can influence the overall quality of the hole being reamed. Variables such as reamer material, reamer design, material being reamed, temperature at the reamed surface, reamer speed, machine or operator movement, etc. must be addressed. By controlling these variables to the best extent possible, the reaming process can easily produce highly accurate and consistently sized holes.

Reamers should not be reversed in use as this will tend to dull the cutting edges.^{[citation needed]}

Size – accuracy and repeatability[edit]

The final hole size that is achieved by a reamer subsequently depends on the reaming process being used in conjunction with the reamer design and materials involved. Studies have been conducted which demonstrate the effect of coolant use during reaming.^[3] The continuous use of a coolant stream during the reaming process has been shown to consistently (75% of the time) result in hole sizes that are 0.0001 in. (0.0025 mm) larger than the reamer itself, with a process spread of +/- 0.0002 in. the remainder of the time. Similarly, using a semi-wet reaming process often results in hole sizes that are 0.0004 in. larger than the reamer itself, approximately 60% of the time, with a process spread of 0.0006 in. favoring an increase in size. Dry reaming should be discouraged due to its low level of repeatability (20%) in size and wide process spread of sizes up to 0.0012 in. (0.030 mm) larger than the reamer size.

Surface finish and longevity[edit]

When properly designed and used, reamers can experience an extended service life of up to 30,000 holes.^[4] A properly controlled process is also capable of maintaining a consistent size down the entire length of the hole while minimizing the hour-glass effect. Reamed holes may typically have a surface finish of 10 to 25 µin. Ra.

Setup and equipment[edit]

Generally, reaming is done using a drill press. However, lathes, machining centers and similar machines can be used as well. The workpiece is firmly held in place by either a vise, chuck or fixture while the reamer advances.^[5]

Tool materials[edit]

Like other cutting tools, there are two categories of materials used to build reamers: heat treated and hard. Heat treated materials are composed by different steels, most notably plain carbon (unalloyed, considered obsolete today) and high-speed steels. The most common hard material is tungsten carbide (solid or tipped), but reamers with edges of cubic boron nitride (CBN) or diamond also exist.^[5]

The main difference between both categories is that hard materials are usually unaffected by the heat produced by the machining process and may actually benefit from it. The down side is that they are usually very brittle, requiring slightly blunt cutting edges to avoid fracture. This increases the forces involved in machining and for this reason hard materials are usually not recommended for light machinery. Heat treated materials, on the other side, are usually much tougher and have no problem holding a sharp edge without chipping under less favourable conditions (like under vibration). This makes them adequate for hand tools and light machines.^[5]

Workpiece materials[edit]

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Aluminum and brass are typical workpieces with good to excellent machinability ratings. Cast iron, mild steel and plastic have good ratings. Stainless steel has a poor rating because of its toughness and it tends to work harden as it is machined.^[5]

Lubrication[edit]

During the process of reaming friction causes the part and the tool to heat up. Proper lubrication cools the tool, which increases the life of the tool. Another benefit of lubrication includes higher cutting speeds. This decreases production times. Lubrication also removes chips and contributes to a better workpiece finish. Mineral oils, synthetic oils, and water-soluble oils are used for lubrication and applied by flooding or spraying. In the case of some materials only cold air is needed to cool the workpiece. This is applied by air jet^[5] or vortex tube.^[6]

Related standards[edit]

National and international standards are used to standardize the definitions and classifications used for reamers (either based on construction or based on method of holding or driving). Selection of the standard to be used is an agreement between the supplier and the user and has some significance in the design of the reamer. In the United States, ASME has developed the B94.2 Standard, which establishes requirements methods for specifying the classification of reamers. ^[7]

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See also[edit]

• Reamer, a type of pipe tool

References[edit]

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1. ^'Chucking Reamers | Gammons Hoaglund'. gammons.com. Retrieved 2020-07-22.
2. ^'Chucking Reamers | Gammons Hoaglund'. gammons.com. Retrieved 2020-07-15.
3. ^'Reamer Study'. Calvalves.com. Retrieved 2013-11-17.
4. ^'Engine Valve Guide Reamer'. Calvalves.com. Retrieved 2013-11-17.
5. ^ ^abcdeTodd, Allen & Alting 1994, pp. 109–115
6. ^'Adjustable Cold Air Gun and Adjustable Hot Air Gun using a vortex tube and compressed air manufactured by ITW Vortec, vortex tubes, vortex tubes, cooling with compressed air'. Newmantools.com. Retrieved 2013-11-17.
7. ^https://www.asme.org/products/codes-standards/b942-1995-reamers

Bibliography[edit]

• Todd, Robert H.; Allen, Dell K.; Alting, Leo (1994), Manufacturing Processes Reference Guide, Industrial Press Inc., ISBN0-8311-3049-0.

External links[edit]