Backpack Deicer

Backpack Deicer

1 Introduction

The Shergood Backpack Deicer provides basic deicing capabilities for small to medium aircraft. The deicer consists of a back mounted 5 gallon tank and a hand-held wand/sprayer.

2 Basic Usage

The deicer consists of a backpack portion which attaches to your spine, and a wand portion which attaches to your hand. Normally, you only directly wear the backpack potion and the wand will either attach automatically or be offered to you to attach. The wand attachment can occur in one of three ways:

1. If you have previously accepted the Shergood Aviation Experience and you are on land that supports the experience, the wand will automatically attach.
2. If you are on land the supports the Shergood Aviation Experience, and you have not previously accepted the experience, you will be asked to grant permission to the experience. This response will be remembered for future uses.
3. If the land you are on does not support the Shergood Aviation Experience, you will be asked for permission for the wand to attach. Click "Yes" to attach it.

Once attached, click the left mouse button to toggle flow of fluid on/off. Face toward the target vehicle to apply fluid to it. The backpack tank is translucent and serves as a visual indicator as to the quantity of fluid, and the type of fluid. Once the tank is empty, the flow will stop and you must refill the backpack before using the deicer again. Follow the instructions in Servicing to refill the deicer tank.

2.1 Rez Requirements

In order to use the deicer, you must have rez rights on the land on which you are using it, both for the wand, and for the invisible "bullets" that are rezzed as part of the system. If the land is a public rez spot, such as at most SL airports, then there should be no issues. If you are on land that requires you to be in a group to rez, there are some caveats due to SCR-395. Due to this SL bug, a wand attached in an area that requires you to be in a group to rez will not be set to that group when it attaches via script. As a result, it will not be able to ez the "deicer bullets" needed to function. A workaround for this is to temporarily changing your group to another group, then back to the land group after the wand attaches. Alternatively, you can manually change the group of the wand by editing it.

2.2 Manual Wand Attachment

If the wand fails to attach for some reason (e.g., you were on no-rez land when attaching the backpack), you can manually attach the wand by clicking on the backpack and selecting "Get Wand" from the menu. This will rez the wand which will then request to attach as explained above.

2.3 Access

You can control which totes can be used to fill your backpack through the Access menu. Click the packback and select Access, then click one of Owner (only owner totes can be used), Group (Only owner or group owned totes can be used), or Public (all totes can be used).

3 De-Icing and Anti-Icing Fluids

Figure 1: Deicer Fluid Totes

3.1 Fluid Types

There are four main times of de-cing and anti-icing fluids used for aircraft: Type 1, 2, 3 and 4. Type 1 fluids are applied hot, have the lowest viscosity and are generally used for removing existing ice from an aircraft. Type 2 and 4 fluids include a thickening agent to make them stick to the aircraft to prevent ice from adhering to it. Type 3 fluids have an intermediate thickness between Type 1 and Type 2/4. Note that the anti-icing fluids Type 2,3,4 generally do not do well at ice removal. For the reason it is generally recommended that line personal first clear ice from the aircraft with Type 1 fluid, then if current weather conditions are conducive to icing, apply the appropriate anti-icing fluid. For Shergood aircraft, Type 3 anti-icing fluid should be used.

Each fluid is characterized by a HOT (Hold Over Time), and a minimum rotation speed. The HOT is the time the fluid will remain effective at preventing ice build-up, and the minimum rotation speed is the airspeed required to shear off the fluid. Type 2 and 4 fluids are generally used on large transport aircraft with high rotation speeds, while Type 3 fluids are used on medium sized aircraft. Type 1 fluids are suitable for all aircraft. The characteristics and colors of the four fluid types are summarized in the table below:

Fluid	Color	HOT (min.)	Min. Rotation Speed
Type 1	RED-ORANGE	n/a	n/a
Type 2	STRAW	0:30	100 Kts
Type 3	YELLOW-GREEN	0:20	60 Kts
Type 4	EMERALD-GREEN	1:00	100 Kts

3.2 Tank Level

The backpack deicer is made of a translucent plastic with the fluid level and color visible through the plastic. When topped off, it will contain 5 gallons of fluid.

3.3 Servicing

Fluid for the deicer is distributed in 250 gallon totes (see Figure 1). There are separate totes for each fluid type. You can identify the fluid in a tote from the color and the label on the tote.

To transfer fluid from a tote to the deicer, using the following procedure:

1. Rez the tote near you
2. Click on the tote
3. The tote will scan the area and search for anything nearby that can accept deicing fluid. Click on your own username to fill your backpack deicer.

If a tote is not completely used, its fluid level will be visible on the side of the container. If the backpack deicer contains a different type than the type of tote you press, the old fluid will be discarded and the full 12.5 gallons will be filled with the new type. If the tote contains the same fluid type, the deicer will be topped off with whatever is required.

By default, totes can only be used by the owner. You can change the access to the tote by clicking on it and choosing "[ACCESS]". You can select between owner-only, group-only and public access. You must also have access to the target vehicle in order to for the tote to detect it.

Totes are available for free from any Shergood store or other distributer. Totes are no-copy and can be discarded once empty. Locations at which totes may be obtained include:

• Shergood Main Store at White Star Airport
• Shergood Store at Cheerport
• Shergood Store at Hollywood

4 About Experiences

For convenience, the wand attachment can be done using an experience rather than requesting permission each time. In SL, experiences are a way to grant permissions one time to a class of devices that are then remembered from then on out. To use the experience method you must:

• Have the land owner grant permissions for the "Shergood Aviation" experience on your land.
• Select "Yes" when attaching the hose for the first time.

After you have granted permissions for the experience, you will no longer need to grant permissions to attach the nozzle as long as you are on land that permits it.

4.1 Granting Land Permissions

To grant permissions for the Shergood Aviation experience on your land, click the parcel name at the top of your view to open the "About Land" dialog box, then go to the "Experiences" tab. Under "Allowed Experiences" select "Add...", then search for and add the "Shergood Aviation" experience owned by Kelly Shergood.