HOVERCRAFT FAQ (Frequently Asked Questions)
By: Alex Olshove
V. 1.33
This FAQ will be updated as required and posted to ALT.REC.HOVERCRAFT at least once a month. It is meant to be used as general reference by those not familiar with the hovercraft. If you reproduce this in any way, I only ask that you give me some credit (unless it's bad). :-) Contents: 1 This FAQ is completely sucky... how can I make repairs to it? 2 What is a hovercraft? 3 The Skirt 3.1 What's the big deal about the skirt? 3.2 What types of skirts are there? 3.2.1 The bag skirt 3.2.2 The segmented skirt 3.2.3 The juped skirt 3.3 Comparison between skirts. 4 The Engine 4.1 How many engines does a hovercraft need? 4.2 What types of engines can a hovercraft use? 5 Okay, a hovercraft sits on a cushion of air but where does the air come from? 5.1 How many fans does a hovercraft use? 5.1.1 Single fan design 5.1.2 Dual fan design 5.2 What types of fans are there? 5.2.1 Axial fans 5.2.1.1 Ducted fans 5.2.1.2 Propellers 5.2.1.3 Propellers vs. Fans 5.2.2 Centrifugal fans 6 How much does a hovercraft cost? 6.1 What are some good sources for buying a hovercraft? 7 Where can I find plans to build a hovercraft? 8 Do you need a pilot license? Driver license? Any US states require licenses? 9 Are there associations and conventions for hovercraft owners? Clubs 9.1 Conventions 9.1.1 U.S.A. 9.1.2 France. 10 Are hovercraft allowed on public roadways? 11 What companies manufacture hovercraft? 11.1 Australia 11.2 England 11.3 Canada 11.4 Holland 11.5 U.S.A. 12 Where can I get more information about hovercraft on the Internet? 13 Can you recommend good hovercraft books to read? 14 Can you make a hovercraft stop and back-up? 14.1 Reversible pitch fan 14.2 Reverse bucket 14.3 Transmission 14.4 Puff ports 15 Can I insure my hovercraft? 16 Aren't hovercraft ‘handicapped’ when it comes to control (stopping/steering)? 17 Do Hoverboards like in ‘Back to the Future’ really exist? 18 Where the heck to do I find 1/8” marine plywood!?! ---------------------------------------------------------------- >1. This FAQ is completely sucky... how can I make repairs to it? Just e-mail me at. I'm not claiming to be an expert so there may very well be errors in this and I'll be happy to fix them or add more information if you want to set me straight. ;-) >2. What's a hovercraft? I'm going to answer this question with a description of newer, popular hovercraft. Perhaps I'll add a history lesson later with descriptions of peripheral jets, etc. A hovercraft is a vehicle which is suspended upon a cushion of air. The cushion of air is generated by a fan which is attached to an engine which is attached to the hovercraft. The cushion of air is contained by a flexible sleeve called a 'skirt' that is attached around the perimeter of the craft to hold the air under the craft and thus upon an air cushion. The craft is then propelled by whatever means is necessary to carry it forward. A majority of craft simply utilize a ducted fan or a propeller attached to a small 2 or 4 cycle engine. Be assured that pretty much every mode of propulsion known to man has already been tried from jet engines to sails. Control of a hovercraft is accomplished primarily through the use of rudders like the type used on aircraft. The main difference would be, however, that hovercraft generally utilize many rudders rather than just one. Another method of control is through 'puff ports' (see 13.1.4) or dual thrust fans where you would slow one down and speed up the other to turn in the direction desired. >3. THE SKIRT >3.1. What's the big deal about the skirt? The skirt is one of the most important parts of a hovercraft as it is the part that allows the hovercraft to clear obstacles. Generally speaking, the higher the skirt, the larger the obstacle that the craft will clear. However, if the skirt is too tall, the craft will 'slide off' the cushion and the cushion will deflate or the craft will become extremely unstable. This is not a FAQ on hovercraft design so I won't go into this in any more detail. On larger craft (> 1 or 2 tons) the skirt is made of heavy, rubberized fabric. On smaller, recreational craft, the skirt is made of neoprene coated nylon that weighs >= 8 oz/sq. yd. >3.2. What types of skirts are there? There are several types of skirts but the most common are the bag skirt, the segmented skirt, and the jupe skirt. >3.2.1. The bag skirt: The bag skirt is basically just that... a bag. The bag skirt should probably be called a tube skirt because it consists of a tube that encircles the perimeter of the craft. The bag is inflated which serves to lift the craft off the ground and more importantly, to contain the air cushion. There are two methods of inflating the bag skirt, the first being serial feed and the second being parallel feed. The serial feed method requires that air be directed from the lift fan _through_ the skirt and then out into the cushion. The parallel feed method requires that a certain amount of air be split off of the lift fan into the skirt (about 10%) and the rest into the cushion. >3.2.2. The segmented skirt: The segmented skirt is also called a 'finger' skirt because it consists of several separate nylon segments that, when inflated, press together to form a shape that looks like fingers of a hand that are pressed tightly together (place your hand into a fist and then look at your knuckles). Although much more complex to manufacture than a bag skirt, the segmented skirt offers much less resistance to obstacles and much more ease of repair when damaged since you only need to replace one or two damaged fingers instead of an entire skirt. Segment skirted craft, however, are less stable than bag skirted craft (not necessarily a bad thing if you race hovercraft). >3.2.3. The juped skirt: The jupe skirt (a.k.a. cell skirt) consists of several cells that look like cones with their tops cut off and have their bases attached to the bottom of the craft. When inflated, these cones readily support the weight of the craft upon a stable cushion. A jupe skirted craft generally utilizes a minimum of 2 or 3 cells surrounded by a large jupe that encompasses the perimeter of the craft. Although a jupe skirted craft is very stable, it will experience difficulty when attempting to inflate the jupes on a rough terrain such a tall grass or deep gravel. Jupe skirts also tend to scoop water in rough conditions and drag on grass. >3.3. Comparison Between Skirt Type (excerpt from 'Light Hovercraft Design' by Christopher Fitzgerald and Robert Wilson): Bag Segment Jupe Cost low high low Labor low high medium Drag smooth water same same same Rough water high low very high Mud high low low Grass high low medium high Ice same same same smooth snow medium low low rough snow high low medium Reparability hard easy hard Life good moderate good Durability good poor moderate Stability good poor Excellent Plow in same same same Roll ability for turning slight excellent none Dust and spray poor good poor Colors available limited unlimited limited Ease of attachment moderate easy moderate hard Weight of skirt low moderate low Hump performance moderate good poor moderate High speed good moderate moderate Bulkiness poor poor good Appearance moderate good moderate Bounce poor good good Performance when damaged moderate good poor Potential for development good good good Over water rapid take off ability from long time floating mode poor good excellent Obstacle capability poor good poor Complexity low high moderate >4. THE ENGINE >4.1. How many engines does a hovercraft need? With the exception of human powered craft, a hovercraft needs at least one engine. With a conventional hovercraft, air needs to be supplied to lift (to make the cushion) and thrust (to propel the craft). The supply of air to lift and thrust can be accomplished using only one engine by either powering a single fan and then splitting an amount of air off to lift (about 33%) and the rest for thrust (called an 'integrated' system) or the one engine can be used to power separate lift and thrust fans. Most hovercraft, however, use a dual engine system where one large engine is used for thrust and another, smaller engine is dedicated to lift. Unlike the integrated system, this allows the craft to remain hovering while the thrust engine is turned off. Larger, commercial craft may use as many as 6 or 8 engines for power of the lift and thrust systems. Engines types range from diesel to gas turbine. >4.2. What types of engines can a hovercraft use? A hovercraft can use (and probably has used) any type of engine you can think of. The main point of concern about the engine to be used is weight. Obviously a high weight to power ratio is bad for a craft that is supported by a cushion of air. Although an air cushion can support a massive load, that load must still be moved and accelerated from a dead stop (and then stopped again when need be). Also, drag becomes more imminent as the weight of the craft increases. So, you must try to keep the engine light and powerful. Currently, the engine with the best power to weight ratio is the 2-cycle engine which is the primary engine used for racing hovercraft. Unfortunately these things are _generally_ noisy and temperamental. Also, they generally require a gear, belt, or chain reduction system to match the fan or propeller they are powering. A large majority of hovercraft utilize the heavier, but quieter, 4- stroke engines. Although these engines put out less power than a similarly sized 2-stroke engine, they are much quieter, don't require a special fuel-oil mix, and sometimes don't require a gear-down mechanism. Large, military or commercial craft will sometimes utilize jet turbine engines that put out thousands of horse power as well as large diesel engines. >5. Okay, a hovercraft sits on a cushion of air but where does the air come from? The answer is 'fans'. Fans are a very important part of a hovercraft whose primary purpose is to inflate the cushion contained within the skirt beneath the craft as well as to provide thrust with which to propel the craft forward. For all intents and purposes, 'fan' in this text will be used to describe any air moving device. >5.1. How many fans does a hovercraft use? A hovercraft can use as many fans as the designer wishes. In fact, the larger military and commercial hovercraft like the Bell Aerospace AALC Jeff (B) uses six lift fans and two thrust fans. In the recreational hovercrafting world, however, most craft function on two basic designs. The single fan or the dual fan design. >5.1.1. Single fan design In the single fan design, one engine powers one fan (or propeller). Most of the air generated by this single fan is directed rearward as thrust while a moderate percentage of the air (c. 33%) generated is split off and thrust below to charge the air cushion contained by the skirt. >5.1.2. Dual fan design In the dual fan design, one or two engines are used to power two, separate fans. One of the fans is dedicated to the generation of air for the maintenance of the air cushion beneath the craft while the other is dedicated to the generation of air to provide forward momentum for the craft. Typically, this configuration utilizes two separate engines but occasionally, you will see a system devised which uses only one engine to power both fans. This often proves to be a more daunting task than using two separate engines as the mechanics involved may become very complex. After all, you need to provide a constant speed to the lift fan while allowing the thrust fan's speed to be moderated. If not, the basic advantage of using two fans is lost. >5.2. What types of fans are there? There are several types of fans that may be used but the two main types of fans are axial fans and centrifugal fans. >5.2.1 Axial fans Axial fans are those that propel air parallel to their axis. Of the axial type of fan, there are propellers and ducted fans. >5.2.1.1. Ducted fans Ducted fans typically utilize several blades that are generally wide at the tip and taper towards the base. A ducted fan may contain as few as 3 blades and as many as a dozen or more. These fans need to be contained within a duct to realize their peak performance. Some advantages of ducted fans include the ability to mount reversing mechanisms such as reverse buckets which direct air forwards when placed in the column of air generated by the fan. Also, ducted fans are generally of a smaller diameter than propellers which can allow several fans to be placed side by side thus allowing for better control of the craft (speed one up and slow one down and the craft turns). One more major benefit that comes from using fans is that fans are readily available from ventilation companies. Ducted fans can be used to provide either lift or thrust. >5.2.1.2. Propellers Propellers typically utilize between 2 and 5 blades that are quite a bit longer than those used on ducted fans. Although propellers are generally more efficient (and safe!) when placed in a duct, ducting is not a necessity as propellers will function well in open air. Propellers must be replaced if damaged by debris whereas a blade is replaceable on a ducted fan. Propellers are generally noisier than ducted fans. Propellers can be used to provide either lift or thrust. >5.2.1.3 Propellers vs. Fans. (Note: This was taken from James Perozzo’s ‘Hovercrafting as a Hobby’ and is best viewed with Courier 10 font.) PROPELLERS FANS More thrust/HP No blade edging Less costly More costly Noisy Quiet Rotate fast Slow Rotation Edge blades avail. Less blade erosion Large Diameter Smaller diameter Must have a guard Duct is also a guard 8’ and more diam. Only to c. 48” diam. Fast throttle resp. Slow throttle resp. Replace whole prop. Replace indiv. blade >5.2.2. Centrifugal fans Centrifugal fans are those that propel air perpendicular to their axis. That is, they draw air in the center and 'fling' it out the side similar to the type used in hair dryers. This type of fan is generally limited to use as a lift fan due to their orientation and relative bulkiness although some craft have been built that use centrifugal fans exclusively. >6. How much does a hovercraft cost? Depends on several factors. A hovercraft could be build for less than $300 if you don't mind that it may only support 100 lbs and only goes 5 MPH. However, if you need a craft that will support 2 adults over water at around 30 MPH, then you will probably spend in the neighborhood of $5000 for a pre-manufactured recreational craft. If you can stand something that's used, you can get a good deal for between $1000 and $5000 for the same craft which will probably get you a trailer as well. If you're handy with a saw and screwdriver then you could build one for less than $1000 or as much as you want to spend. All in all, the cost boils down to the materials used to manufacture the craft (fiberglass or plywood?), the time spent, the engine(s) (Rotax 503 or B&S 12 HP?), the fan(s), the skirt (bag or segmented?), and the gadgetry (Radio? electronic actuators? elevons?). >6.1. What are some good sources for buying a hovercraft? The HoverClub of America's bi-monthly publication called 'The HoverNews' lists several good deals in the classifieds section in the back. Also, there are a few hovercraft related pages on the Web that have a classifieds section. You can also order a brochure directly from the manufacturers listed below. >7. Where can I find plans for building a hovercraft? Why not design your own? If you're not feeling that confident, then try the dealers listed below: Sevtec Inc. PO Box 846 Monroe, WA 98272. 794-7505 sevtec@aol.com Models: Scout ($29) Vanguard ($44) Prospector ($48) Explorer ($62) Mariner ($92) http://members.aol.com/sevtec/sev/skmr.html Universal Hovercraft 3rd Street Box #281w Cordova, IL 61242 Phone / Fax (309) 654-2588 Complete Catalog $2.00 Too many plans to list http://www.hovercraft.com Databoat International, LTD. PO Box 1073, 8609 Fissile Lane Whistler, BC Canada V0N 1B0 databoat@whistler.net Models: Neoteric Neova 4 ($143.50) http://www.databoat.com/27hover.htp Robert Q. Riley Enterprises Box 12294 Scottsdale, AZ 85267-2294 Phone: (602) 951-9407 rqriley@netzone.com Models: Tri Flyer ($45) Pegasus ($35) http://www.netzone.com/~rqriley/plans.html >8. Do you need a pilot license? Driver license? Any US states require licenses? Nope. >9. Are there associations and conventions for hovercraft owners? Yes, here is a list of Clubs followed by some annual conventions. >9.1. Clubs Australian Hovercraft Federation Michael Nell 17 Fegen St., Huskisson, NSW 2540, Australia Email: nell@mpx.com.au Title of Publication: Australian Hovercraft News Frequency of Distrbiution: Quarterly Cost of subscription: Australia AUS$20.00; USA US$25.00 Contact: Tim pryor, Editor, Australian Hovercraft News [tpryor@mail.fairfax.com.au]. 38 Barnes Road, Frenchs Forest, New South Wales 2086, Australia Hovercraft Club of Canada 10 Gold Crescent Russell, Ontario CANADA K4R 1B4 Tel / Fax: (613) 445-3139 Bob Rennick Title of publication: 'Hovercraft Club of Canada Newsletter' Frequency of distribution: Four times a year Cost of subscription: Membership in the club ($15/yr) http://www.peaceregion.com/hover/ Hoverclub of America PO Box 908 Foley, AL 36536-0908 Phone: (334) 943-3279 Title of publication: 'HoverNews' Frequency of distribution: Every two months Cost of subscription: Membership in the club ($30/yr). Http://www.hoverclubofamerica.org/ Hoverclub of South Africa 5 Marais Street Somerset West 7130 SOUTH AFRICA Title of publication: Frequency of distribution: Cost of subscription: Belgian Hoverclub Blvd St. Michel 78 1040 Brussels BELGIUM Title of publication: Frequency of distribution: Cost of subscription: RHONE ALPES AEROGLISSEURS Jean CLAUDE DELORME RUE DU MONT CINDRE ST CYR AU MONT D'OR FRANCE Title of publication: "POTIN d'AEROS" Frequency of distribution: bi-monthly (once every two months) Cost of subscription: 12 (Francs?) Hoverclub von Deutschland Lechfeld Str. 2 Mering GERMANY Title of publication: Frequency of distribution: Cost of subscription: Hoverclub of Great Britain Secretary: Mrs Brenda Kemp Long Acre, Bingham, Notts, NG13 8BG Title of publication: Light Hovercraft Frequency of distribution: Cost of subscription: Editorial contact: Jeremy Kemp Long Acre, Bingham, Nottingham, NG13 8BG The Netherlands Hovercraft Club Uiterdijksehof 5, JK Nederhorst den Berg HOLLAND Title of publication: Hovercraft Sportnieuws Frequency of distribution: Cost of subscription: Japanese Hovercraft Association C/o SOREX Co. Ltd. KOUMENAKA Kumenan-cho, Kume-Gun OKAYAMA-KEN, 709-36 Title of publication: Frequency of distribution: Cost of subscription: Hovercraft Club of New Zealand David Van Bysterveldt Robinson Rd, 4, Paeroa Phone 64-7-862-4793 NEW ZEALAND Title of publication: Hover News Frequency of distribution: Cost of subscription: Wellington and Wairarapa (New Zealand) Hover Club Kerry Workman Harvard Grove Totara Park Wellington. New Zealand Phone: (04) 5267655 http://www.voyager.co.nz/~arthurg/ arthurg@voyager.co.nz Swedish Hoverclub Ollonvaegen 17 Akersberga SWEDEN Title of publication: Hover News Frequency of distribution: Cost of subscription: > 9.2. Annual Events There are many annual events around the world. Here are some of them listed by country. For more specific information, visit http://www.hoverclubofamerica.org/events.html courtesy of the Hoverclub of America. >9.2.1. U.S.A. What: West Coast Hover-In and Cruise When: July Where: Long View, Washington What: The U.S. National Cruise on the Wisconsin River When: August Where: Muscoda, Wisconsin What: Scioto River Hover-In & Cruise When: August Where: Chillicothe, Ohio What: Tennessee Hover-in When: October Where: Big Spring, Tennessee What: Texas Hover-In When: October Where: Dallas/Ft.Worth Texas What: 23rd National Annual Hoverally When: June 12,13, & 14, 1998 Where: Troy, Ohio >9.2.2. France What: The World Hovercraft Championship When: August Where: Luçon in the Vendée, France >10. Are hovercraft allowed on public roadways? Nope. And you probably wouldn't get very far if they were since most roads are 'humped' up in the middle to allow for water run-off. Unfortunately, this also causes air cushion vehicles to slide off to the side of the road since there is no friction to hold 'em on there. If you're a skilled driver, then you can counteract the sliding affect by directing the nose of the craft towards the center of the road and 'crab' sideways like you would during heavy wind. >11. What companies manufacture hovercraft? The companies listed below are categorized by country. >11.1. Australia Airlift Supercraft (Aust) Pty.Ltd. Olsen Avenue ASHMORE, 4214 Queensland Australia Phone: Australia 07 5527 8111 Fax: Australia 07 5527 8016 Models: AS 400 Thriller AS 560 Hoverflyer AS 560U HoverUte AS 600C Mustang AS 600A Mustang Ambulance AS 8900 Pioneer AS 10600 Pioneer L(ong) AS 1200 Challenger TURBO Hovercraft Pty. Ltd. Vortex Hovercraft Pty. Ltd. Models: Turbo 235 Superwedge 225 Wedge Vortex 245 Turbo 265 Super Turbo 265 Hyper Rocket Revolutionary Technology 11 Mulberry Court Eltham Victoria, Australia, 3095 (Owen Ellis designer of Rocket) Models: Rocket (seen by many at the last world championships) >11.2. England Pegasus Aviation Elm Tree Park Manton, Marlborough, Wiltshire, SN8 1PS ENGLAND, UK. Tel. + 44 (0)1672 861578 FAX. + 44 (0)1672 861550 pegasus@cccp.net Models: Cyclone PRIMO http://ayla.avnet.co.uk:80/pegasus/caprimo.htm#primo Bill Baker Vehicles Eagle Hovercraft Ingles Hovercraft Associates Ltd. Ingles Manor Castle Hill Avenue Folkestone, Kent CT20 2TN ENGLAND, UK Models: River Rover >11.3. Canada AeroTour Canada 1279 boul. Hurtubise Gatineau, Quebec, J8P 7C2 Tel.: (613) 762-3167 Voice and fax: (819) 669-8454 http://www.angelfire.com/biz/aerotour Canair Hovercraft Inc. O. Box 478 Carleton Place, Ontario K7C 3P5 Telephone: (613) 257-8332 Facsimile: (613) 257-7948 Models: Canair 504L http://local40.pr.incentre.net/~hover/canair.htm Surface Effect Boats (S.E.B.) Enterprises Inc. Models: AirCat 7 >11.4. Holland Hovertrans B.V. Keizersveer 9 LD HANK The Netherlands Telephone: +31 1622-3062 Tel/Fax: +31 1622-3075 hovertrans@pi.net Models: Colibri Hurricane HP Design Uiterdijksehof 5 JK Nederhorst den Berg NETHERLANDS Models: Sprinter >11.5. U.S.A. Hovercraft America N114 W18605 Clinton Dr. Germantown, WI 52033 Phone: 414.253.9979 FAX: 414.253.9033 hover@execpc.com Models: HA-5 http://www.execpc.com/~hover/index.html Hovercraft Concepts 13910 SW 139 Court Miami, FL 33186 305/256-8696 FAX: 305/256-8698 Contact: William Flett Models: SA 580 Aerocruiser SA 1100 (price: $12,995) HoverDynamics JAKenney@aol.com Models: Starcraft RX2000 GPL Enterprises Contact: Gary Lutke Tangelo Terrace #A13 Delray Beach, FL 33444 Phone: (407) 274-2247 or (800) 541-7228 Fax: (407) 276-4159 Models: Air Commander Neoteric Hovercraft Inc. Tippecanoe Street, Dept.. 12 Terre Haute, IN 47807-2394 Telephone: (800) 285-3761 Alternate Phone: (812) 234-3217 Fax Phone: (812) 234-3217 Hovercraft@delphi.com http://www.sapphire.com/UNCAT/uncat135.html Oregon Hovercraft 27612 Crow Rd. Eugene, OR 97402 Telephone: (541) 485-0588 hiblerp@continet.com http://www.continet.com/hovercraft/ Sevtec Inc. PO Box 846 Monroe, WA 98272. sevtec@aol.com Models: Scout Vanguard Prospector Explorer Mariner http://members.aol.com/sevtec/sev/skmr.html Hovertechnics Inc Contact: Hugh B. Firminger Box 257 St. Joseph, MI 49085 Phone:(616) 925-0025 Fax: (616) 925-6940 Models: HoverJet Weber Hovercrafts 28728 Crabtree Corner Road Cuba City WI 53807 vweber@mhtc.net Phone: (608) 744-3678: Verdon Fax: (608) 759-5704: Vernon Models: StarCruiser 1-4 Price: $3400 + SCAT Hovercraft of Washington PO Box 4838 Federal Way, WA 98063 voice (206) 838-5005 or (888) NEW-SCAT New Mexico Scat P O Box 90575 Albuquerque NM 87199 Dan Morris Phone: 505-828-2273 St. Louis Hovercraft Rides Inc. P.O. Box 73 Chesterfield, MO 63006 Michael Murphy (MURHOVER@aol.com) Models: HoverStar HoverJet http://members.aol.com/MURHOVER/index.html >12. Where can I get more information about hovercraft on the Internet? When I first started the Hovercraft Homepage, there was no, none, zip, zero, nada information about hovercraft on the Internet. Now there are hundreds of web pages to access. If you're too lazy to do an Alta Vista search, here are what I consider to be the main pages: http://www.olshove.com/HoverHome My Hovercraft Homepage. http://www.hovercraftersresource.com/ Kelly Jernigan's Hovercraft Resource. http://members.aol.com/sevtec/sev/skmr.html Barry Palmer's Sevtec page. http://www.hoverclubofamerica.org/ The HoverClub of America's Official Homepage. http://www-personal.umich.edu/~untitled/hover.html HoverTechnic's Page. http://www.ozemail.com.au/~ahf/index.html The Australian Hovercraft Federation Page. http://www.ils.nwu.edu/~eric/hover.html Eric Goldstein's page. http://www.innotts.co.uk/~pault/hcgb.htm The Hoverclub of Great Britain Homepage. http://www.hovercraft.com Universal Hovercraft. http://www.peaceregion.com/hover/ The Hovercraft Club of Canada Homepage. There is now one newsgroup relating to hovercraft called alt.rec.hovercraft. If you don't see it on your local news server then please e-mail root@ (root@xoom.com or root@netcom.com, etc) and request that they start carrying alt.rec.hovercraft on your news server. An easy way to read and post to alt.rec.hovercraft is through a service called DejaNews. You can get to this service via your web browser by entering http://www.dejanews.com as the location. When you get there, you can simply enter ‘alt.rec.hovercraft’ in the edit box marked ‘Type a specific question or topic:’. I have the capability to start a mailing list but I want to see how the news group does for awhile before I consider maintaining such a pain in the hoo-ha. >13. Can you recommend good hovercraft books to read? Sure thing. In fact, these were the primary sources for this FAQ (other than from my noggin that is). ;-) Title: Hovercrafting As a Hobby Author: James Perozzo Subject: All aspects of hovercraft design for recreational use. Available From: Twin Peaks Publishing; 30455 Kent-Blk Diamond Rd., Auburn, WA 98092. (253) 631-7347. NOTE: The author has passed away and this book is out of print. If you can get a copy, it’s a good book for beginner to intermediate. Title: Jane's Surface Skimmers Author: Jane's USA Subject: General hovercraft reference. Lists darn near everything ever built. Available From: http://www.janes.com/. Your best bet for getting your hands on one of these rather expensive references is to search for a used one through a book exchange. Title: Light Hovercraft Design Author(s): Christopher Fitzgerald and Robert Wilson Subject: General hovercraft design reference. Available From: The Hoverclub of America. See above for contact information. >14. Can you make a hovercraft stop and back-up? Yes, although it requires some mechanical wizardry since no part of the craft is in contact with the ground. This is generally accomplished via reversible pitch fan, 'reverse bucket', transmission, or 'puff ports'. >14.1. Reversible pitch fan A reversible pitch fan (or propeller) is a fan that allows the operator to physically reverse the pitch of the fan blades thus reversing the flow of air forward thus slowing and/or reversing the direction of the craft. These are mechanically complex and are not useful in a craft of single fan design (see 4.1.1.a) since the reversing of the airflow would essentially create a vacuum in the cushion and suck the craft to the ground. >14.2. Reverse bucket A reverse bucket is placed, mechanically, directly rearward of the thrust fan to redirect it's airflow forward via a curved surface when the operator wishes to slow the craft or stop. Although this method is much simpler than a reversible pitch fan, the bucket adds weight to the rear of the craft in addition to the engine, duct, fan, and rudders. Also, reverse buckets are only useful with smaller diameter fans. >14.3. Transmission A transmission is sometimes as complex a solution as a reversible pitch fan. As in an automobile, a transmission reverses the rotation of the fan and is attached to the driveline between then engine and the fan. A transmission may utilize gears as in an automobile or belts as in a 'mule drive'. >14.4. Puff ports Puff ports are apertures through which air is redirected from the lift or thrust system to the front or sides of a hovercraft. When a puff port is opened, the air is allowed to flow out of the craft in whatever direction the operator desires. Realistically, puff ports are only useful at slow speeds since they often lack the ability to pass air at a sufficient velocity to counteract a craft with much momentum and are used primarily for low speed maneuvering. >15. Can I insure my hovercraft? Currently, insurance for hovercrafts is very difficult to obtain (in the USA anyway). Most insurance companies don't even know what a hovercraft is but may insure your craft as a boat >16. Aren't hovercraft ‘handicapped’ when it comes to control (stopping/steering)? Nope, we prefer to see those as "limitations of frictionless motion". It could as easily be said that automobiles suffer from the handicap of not being able to move over water or that boats suffer the handicap of not being able to transition to land travel. The primary advantage of the hovercraft is that you can fly them over any relatively flat surface on land, snow, mud, water, swamp, peat bog, river, etc. They are being used more and more often for rescues, ferrys, and general grins (_big_ grins). Advances are gradually being made in control. We've learned, for instance, that a tighter, more controlled turn at speed can be made by tilting the hovercraft to one side and banking it through a turn. This can be accomplished by operator weight shift, elevons, or cushion control mechanisms. The resulting control starts to approach that of your average speed boat on full plane and exceeds that of your basic automobile on an icy highway. ;-) Braking is accomplished fairly effectively through the use of thrust reversing mechanisms such as reversible pitch propellers, and reverse buckets. True, hovercraft don't offer the best response times for braking and steering as water plows (boats) and automobiles but owners/operators of hovercraft would agree that the advantages of hovercraft travel outweigh the disadvantages which, by the way, are adjusted to as the operator gains experience. >17. Do Hoverboards like in ‘Back to the Future’ really exist? Figure it this way. An axial fan puts out only so much lift per horsepower. In hovercraft terms this is measured in pounds per square foot. A good lift system will produce 10 lbs per sq. ft. Multiply the the area of the hovercraft by the lbs-sq-ft for a rough idea if it will work or not. How big is the hoverboard? 1' x 4' ? That is 4 square feet. With a good lift system you will have 40 lbs of lift total. Now, how much do you weigh? Note: This explanation was graciously provided by Dave Galka who is the editor of HoverNews for the Hovercraft Club of America. In summary, a 1’ x 4’ board is capable of supporting about 40 lbs. Unfortunately, most humans weigh much more than this. Sorry, but hoverboards will not be a possibility unless a seriously powerful power source can be devised. Preferably one that can supply at least 40 lbs per square foot and still fit within the confines of 1’ x 4’. >18. Where the heck to do I find 1/8” marine plywood!?! Okoume is a fairly common mahogany 3-ply marine plywood available from numerous sources. It is light, bends easily and is moderately durable. Below are some suppliers: M.L. Condon Co., Inc. 260 Ferris Ave. White Plains, NY 10603 914-946-4111 914-946-3779 (fax) Marine grade okoume - 3 mil, 4x8 $40 / sheet Edensaw Woods, Ltd. 800-745-3336 PortTownsend, WA www.olympus.net/edensaw/ Marine grade okoume - 3 mil, 4x8 $37 / sheet Boulter Plywood Corp. 24 Broadway, Dept WB Somerville, MA 02145 617-666-1340 617-666-8956 (fax) Marine grade okoume - 3 mil, 4x8 $39 / sheet Harbor Supply 1401 Russell Street Baltimore, MD 21230 800-345-1712 410-752-0739 (fax) Exterior grade okoume - 3 mil, 4x8 $24.68 / sheet Marine grade okoume - 3 mil 4x8 $53.20 / sheet