Archived Messages
Count,MessageID,category,ShortTitle,Message,Date,UserName,MsgPswd,Phone,Email,ParentMsgId
"1","904809","10","Req for Technical Paper||904809","Where can I find this paper Altman, R., "The Design of Supercavitating Hydrofoil Wings," Technical Report 001-14, Hydronautics Inc., April 1968[. Can somebody email me the pdf version of this paper at the following mp_mathew@hotmail.com.","2005-10-01","M.P. Mathew","nopswd"," ","mp_mathew@hotmail.com","10"
"2","888646","10","Re; Could Hyrdofoils do the job||888646","Foils are probably more complicated and expensive than what you need. The biggest problem as you pointed out is that there are no planing surfaces on the bottom of the hull. I suspect a long, narrow board attached to the underside of each of your hulls will be cheaper, and give you what you want. I'd try a piece of plywood about a foot wide, starting from halfway back and running to the trailing edge of the sponsons, mounted so it is level at rest. If the engine doesn't give you enough bow rise to allow the boards to plane you may need a small board with a positive angle of attack at the front. Once you get it to plane at full load, carve away at the board until you determine how small it can be. Then remove it and replace it with a fiberglass board (cut from the side of an abandoned hull if need be). Be carefull when you first get it to plane, if there isn't an angled planing surface at the front it may try to turn into a torpedo when you breach a wave or drop the throttle suddenly. By adding a planning surface you should be able to get it higher in the water with no moving parts, and nothing to interfere with shallow water or beaching.","2005-09-05","Scott Smith","nopswd"," ","boatswithwings@adelphia.net","10"
"3","879787","10","Re; Question on hydrofoils abilities||879787","Maxx,
To repeat an earlier post, see photos of a successful kayak on foils at www.foilkayak.com .
","2005-08-19","Mac Stevens","nopswd"," ","stevensm@earthlink.net","877174"
"4","877903","10","Re; Question on hydrofoils abilities||877903","See: http://www.foilkayak.com This is a worked out foiling kayak that has done over 20mph under paddlepower.It uses foils readily available from Fastacraft( http://www.fastacraft.com )","2005-08-16","Doug Lord","nopswd"," ","lorsail@webtv.net","877368"
"5","877368","10","Re; Question on hydrofoils abilities||877368","I timed it yesterday and the skyski will glide about 8 seconds, relesing at 21mph before it settles into the water. Take a look at human powered foil watercraft, and nearly all are powered by the legs, which offer far more energy than you can get from your kayak paddles. As with the aquaskipper (http://www.inventist.com/products/aquaskipper.html), you have to have a lot of speed (a good push-off from a solid dock) before it is moving fast enough to fly. But it is available from www.hammacher.com for $500 complete, and inventist says they can sell the foils as replacement parts. (The foils are aluminum and look perfect.) Lacking local technical knowledge, I'd suggest starting with something that works, especially in your speed range and go from there.","2005-08-15","Barry Steele","nopswd"," "," ","877174"
"6","877174","10","Re; Question on hydrofoils abilities||877174","Hi,
Thanks to Barny and Berry for the information. Given the information, and looking at the web sites and the videos, I think that it looks like hydrofoils can glide reasonably well.
As a project I would like to try and put a couple of hydrofoils on a kayak and see if it can glide while paddling, but without costing too much. However, although I understand the basic principals, I do not understand them to their fullest.
I get from some websites that a cambered foil has more lifting action than a non-cambered foil, but am I correct that I do not need it to be cambered as it is going through water which should provide a lot of lift?
Also, how critical is the cut of the foil? Can I approximate it with only two or three line segments per surface (top and bottom)? Or would I need many more so as not compromise too much lift?
Are there free calculators that I can get hold of to get an idea of the cut and the length of the foil as well as the amount of lift and drag? I saw one package going for over $600 but I am not able to devote that much money to this project. Another calculator I saw calculates the “NACA 4 Digits Series” and yet another one that calculates the “NACA 5 Digits Series” . What exactly does this mean? Are they something that I should be using? Unfortunately, it does not give me info on lift and drag.
Thanks for all of your help.
Maxx","2005-08-14","Maxx On","nopswd"," ","maxxon@animail.net","875804"
"7","876133","10","Re; Question on hydrofoils abilities||876133","My guess is it would depend on the efficiency of the foil, but here is my experience: A skyski (www.skyski.com) at 20 mph glides a very long way once the towline is released (Much further than skis). Another craft, the Tramp-o-foil, now marketed as the Aqua Skipper (http://www.trampofoil.info/aquaskipper.html) will glide about 40' with just a push off a dock. It relies on gravity making it glide forward (and downward). When the rider jumps up, taking his weight off the craft, the rear foil is pointed upward, bringing it toward the surface for the next cycle. (It's a fun craft, a little tough to learn, lots of work and hard on the legs.)","2005-08-12","Barry Steele","nopswd"," "," ","875804"
"8","876067","10","Re; Question on hydrofoils abilities||876067","Hopefully one of the engineers who follow this BBS will quantify the glide time for you, though there are are several variables. Meanwhile take a look at a photo of a PHM hydrofoil missile boat coming down off its foils in an emergency landing drill (in this case, controls are used to get the ship back foilborne and stopped). Go to: http://www.foils.org/gallery/phm5emla.jpg","2005-08-12","Barney C Black","poopdeck"," "," ","875804"
"9","875804","10"," Question on hydrofoils abilities||875804","My question is can a hydrofoil craft glide in (relativity calm) water.
Given that water has a lot more friction than air, it would seem to me that any foil attached to a boat, even a small one, would have a lot of drag and therefore not be able to glide (i.e. have an initial impulse of forward motion and have the boat stay above the water for a short duration, maybe 5-10 seconds) in the water. If it is able to glide, just how far or how long can it glide?
Am I correct on this?
Maxx","2005-08-11","Maxx On","xx"," ","Maxxon@animail.net","10"
"10","862461","10","Re; Could Hyrdofoils do the job||862461","David Keiper designed hydrofoil kits for Hobies, and his papers on this are available for sale from IHS, but this design was for sailing. Take a look at the HYSUCAT webpages... this design places foils between the catamaran keels. Explanation of how this works is at:
http://www.hydrospeed.co.za/index2.html","2005-07-18","Barney C Black","nopswd"," "," ","0"
"11","861961","10","Could Hyrdofoils do the job||861961","A personal interest led me to try and motorize a set of Hobie Cat 18 hulls. I have created a firm fibreglass deck between the hulls and welded up an aluminum transam with a 30 hp long shaft Johnson Outboard, with controls mounted on a center consol, mid ships. She floats well and is as level as I could wish for. She rides well, with one person in flat water. However,due to the hull design,she lacks boyancy and this makes her struggle in any kind of chop, or with any extra weight. The ribs below the deck, which were fibre glassed in for strength, catch any solid water and the boat is slowed dramatically, throwing the occupants forward slightly. Had the clearance between the under side of the deck and the water surface been greater, the project would have been succesful. Approximatly half the hull height is above the surface, while under way.
I am researching ways to create the boyancy, or lift that I need while under way,which will increase the distance between water surface and the under side of the deck, and was wondering if anyone thought that some form of hydrofoil or lifting apparatus may help. Needless to say, creating an apparatus that requires lots of water depth, or increases the draft of the boat, to accomodate the new design, defeats the purpose.
I am aware that the hulls were never designed to plane nor were the hulls designed to do this. Either I give up and admit defeat, or I do something extra ordinary and succeed. I am hoping that there is someone, out there, who has a great in-expensive idea that may make this work.
The overall idea is that I would have a flat water boat that could cruise around in the shallows, carry three or four adults, be pulled up on to the beach, run at a reasonable speed, and handle other boat wake with relative ease.
If any one requires photo's to assist with this project, please feel free to ask for them.
I would love some assistance
Thanks
Steve de Klerk
stephenson2006@bellsouth.net","2005-07-16","Steve de klerk","nopswd"," ","stephenson2006@bellsouth.net","0"
"12","828124","10","Re; Foil Design Help||828124","I have a friend who is a competition wake-boarder, and we have had the same discussion. Here are a few of the details we have considered. You always have to concern yourself with the possibility of striking debris. If your foil is strong enough and rigid enough, it would probably survive a hard strike at the relatively low speeds used by wake boards, but you might need hull strengtheners at the mounting points. If you made the foil so it would get knocked off and recovered (common for small foil boats), then a centerline foil would have the highest possibility of ending up in your prop. Don't forget you need to remove or retract the foil to trailer the boat. And side mounted foils usually have to be retracted or removed to approach a dock. A front mounted foil will only lift the front end of the boat, limiting the down force on the rear of the boat to whatever weight is available. But if you were to attach a foil to the transom of the boat instead,(foils can pull down too) you could get as much downward force as the foil area and engine power will allow. The foil could easily be trimmed and retracted without complicated gear, and would remain outside the boat when retracted. Perhaps the struts could attach to the leading edge of the foil with hinge points, while the rear could be attached to trim actuators via springs. In this way the springs would allow the foil to pivot under varying loads and boat angle-of-attacks, while keeping the downward load fairly constant. During a strike the struts could pivot up, while the foil angle decreases. This could be important because if you let the struts pivot up with the foil rigidly mounted to them, the ensuing increase in angle of attack on the foil would try to tear the transom off your boat. If the foil pivots up instead of knocking off, you won't have to worry about your buddy on the wakeboard hitting the detached foil. Your foil(s) won't need to be very large, I would consider using two inverted 'T' foils, one on each side, to keep them somewhat out of the prop wash. Since efficiency isn't an issue for wake-boarders, you could probably make the foils a little thicker and out of G-10 (FR-4) fiberglass, machined to shape. We use the stuff to make supersonic rocket fins, it is very stiff and very strong. Good luck with your project, let us know what you come up with.","2005-05-13","Scott Smith","nopswd"," ","ssmith@veinrxinc.com","0"
"13","824679","10","Foil Design Help||824679","Gday mate my name is sam doolan and I am an Industrial design student from
RMIT university Melbourne Australia. I am currently designing a foil, which
creates larger wakes for wakeborders by lifting the front of the boat and
transferring the weight to the back, to give it larger wakes. However I am
sure how the foils should be designed. Wether one at the front of the boat,
or coming off both sides or both. Would you be able to answer this question
for me.","2005-05-06","sam doolan","nopswd"," ","doolans@bigpond.net.au","0"
"14","821854","10","Students Need Help Design, Build Hydrofoil||821854","I have available 3 sets of plans for just such a craft I'd be glad to email to you. They can give you a good idea of a place to start. email me at barry_steele@yahoo.com","2005-05-02","Barry Steele","nopswd"," "," ","0"
"15","820981","10","Students Need Help Design, Build Hydrofoil||820981","Hello,
We are five ambitioned german design students and we're working on a hydrofoil for six months. it's a projekt provided by the professorship for technical design.
in this stage we're on our way to build a prototype to be able to do several tests on the water.
We have already defined the dimensions (length 2,50, weight 140 kg pilot within, power of engine 4 hp, take of speed 13 mph, cruising speed 25-30mph) and are now trying to get answers from several sources (technical universities in hamburg and duisburg we have already contact with) on questions about the foil configuration like:
Which profile is the best to use for a boat like this (maybe you can propose several naca numbers to test)
Which angle of the v- wing is suitable, is there one that's perfect or in which range is it sensible to test
we know that it is difficult to give detailed information on these subjects but any advice would be precious for us to find a starting point.
we want to take reallife tests as soon as possible to get the results we need
great thanks
the team flying dutchman
basti
leo
jan
daniel
jonas
","2005-04-30","white","nopswd"," ","whitewn@speakeasy.net","0"
"16","787545","10","TIPE||787545","Bonjour Romain,
Je suppose que c’est pour un TIPE.
Je te contacte sur ton email perso.
A plus,
Gérard Delerm
http://gerard.delerm.free.fr
PS: sorry for this french message
","2005-02-26","Gérard Delerm","nopswd"," ","gerard.delerm@free.fr","0"
"17","787317","10","Information on struture of foils & materials||787317","bonjour
je suis actuellement élève en classe préparatoire et je dois mener un projet en vue des concours.J 'ai décidé de m'intéresser aux foils avec pour thème: erreurs et évolution des connaissances. Donc si vous avez des informations sur ce thème merci de m' en faire connaissance.je cherche aussi des renseignements sur la struture des foils et les matériaux qui les composent, ainsi que des explications sur les phénomènes de cavitation et de ventilation.
Je vous remercie d'avance
Romain Dumont :23 bis rue de la varenne 94100 saint maur des fosses
PS:si vous voulez plus de précisions sur ce que je recherche, n' hésiter pas à me le demander
I am currently student in class preparatory and I must take a project regarding the concours.J 'decided to be very interested in me the foils with for theme: errors and evolution of the knowledge. Therefore if you have the news on this theme thank-you of m' some done connaissance. I looks for also pieces of information on the struture of the foils and the materials that the compose, as well as explanations on the phenomena of cavitation and of ventilation. ","2005-02-25","Chris Huxley-Reynard","nopswd"," ","chris_huxley_reynard@hotmail.co.uk","0"
"18","770512","10","vs8 pictures||770512","I am looking for any pictures of the vs8 particularly on the prop rudder area - I can not contact challenge publications to see if they had an old copy of the scale modeler magazine from july 82 which showed photos of the 32nd parallel kit","2005-01-25","David Short","nopswd"," ","davidsh@internode.on.net","0"
"19","755409","10","Boat Hulls ||755409","Hi Austin, good luck with your product. Maybe you have heard about the Raingutter Regatta. This is a boat race held by Boy Scouts of America. The scout store and some hobby stores sell a kit of parts from which you build your boat. You could get three of these kits, make three different designs and race them. Here are a couple of good pages I found googling:
http://pack655.ocbsa.org/raingutter_regatta.htm
http://webpages.charter.net/cschott/boat/supercat.html
Hope this helps you with ideas. ","2004-12-23","Barney C Black","foilsadm"," ","bcblack@erols.com","0"
"20","753494","10","6th grade science fair project||753494","Hi, I would like to do a science fair project on aero dynamics - Hydro plaining. I am going to build 3 small boats out ot bass wood with different type bottoms. ( to test which go through the water the best and which are more stable. Do you have any ideas that couldmake my project more interesting or detailed. I would appreciate any information. Thank You,
Austin Eastman
6th grade
Ponderosa School","2004-12-18","Austin Eastman","nopswd"," ","kerritallerico@yahoo.com","0"
"21","743423","10","Re: student project||743423","Hi Justin, I note that your photo did not upload to the BBS... maybe the file size is too large. I suggest you email it with attached text background and description to: editor@foils.org with copy to gallery@foils.org.","2004-11-24","Barney C Black","poopdeck"," ","barney@alum.mit.edu","0"
"22","743094","10","picture||743094","","2004-11-24","Justin Lohrmeyer","nopswd"," ","justin1983@sbcglobal.net","0"
"23","743079","10","student project||743079","Hello,
I am a student at the university of Kansas and I decided to involve myself with personal watercraft design.
I am not an engineer so much of my work is on creating a comfortable arrangement for the rider while maintaining a fast and wild experience.
I thought that if I used foils to lift the craft it would be faster and smoother.
The rear foil is intended to move up and down according to suction and speed. This means that if you jump slightly the foil will respond and lower itself as to maintain suction and acceleration.
I thought that something with the equivalent hp as a 900cc 4 stroke could do the trick.
After looking at some of the stuff on this site I think I am not too crazy for going where I am going.
Tell me what you all think, I enjoy criticism.
","2004-11-24","Justin Lohrmeyer","nopswd"," ","justin1983@sbcglobal.net","0"
"24","721719","10","kite hydrofoils||721719","I have recently competed in Weymouth speed week on a kitesurf kite and standard board and have posted a speed of 30.97 knots.
I wish to increase the speed and the only thing I believe is stopping me is the boards resistance. I wish to try out hydrfoils on my board that will lift the board approx 5-10 cm off the surface of the water. I have thoght about using hydrfoils off model boats.
The hydrofoils will have to be made of metal I think. Has anyone got any suggestions of where I could get such things from or made?
The board I am using is 130cm long and 37cm wide.
I look forward to your suggestions
Richard Gowers
Uk","2004-10-11","Rich Gowers","nopswd"," ","info@surf-skate-ride.co.uk","0"
"25","699977","10","Re: model rocket boat||699977","Sounds like an interesting project. I doubt you will buy yourself much improvement by using foils. The impulse from that engine is so short, the weight and complexity of the foils will probably cost you more than the gains. And stability will be trouble, high thrust for short duration, then unpowered cruise to the finish, plus induced drag from the depth the foils will need to penetrate in order to get adequate control. Hard to argue with a planing hull for that application. Have you considered a ram-rocket? In it's complex form a ram rocket utilizes unburned powder in the exhaust to increase efficiency, not very applicable to your needs. But in a simpler form, a ram-rocket set up as a venturi may be quite helpful. Rockets by nature provide very high speed capability (HP), while producing little total thrust (torque). In the days of jet-x engines, venturi tubes called augmenters were used to increase static thrust. It is much like gearing a car engine. Since your boat won't be able to do 300mph (where those rocket engines really start to work), trade some of the top end for more thrust. A venturi made from your aluminum should be able to double your thrust without limiting the boats top speed. I've seen venturis claimed to have 5:1 ratios, but a 2:1 or 3:1 ratio is certainly achievable. The overall weight of your boat with an augmenter tube will probably be lighter than a foil design, and that helps too.","2004-08-26","Scott Smith","beatrice"," ","ssmith@syntheon.com","0"
"26","694260","10","Re; Solar Electric Boat Design||694260","Brad
You might try the Human Powed Links section of our web site for some help with your questions.
http://www.foils.org/linksout.htm#human
Rill ","2004-08-13","Bill White","nopswd"," ","whitewn@speakeasy.net","0"
"27","689509","10","Solar Electric Boat Design||689509","I have a question that you might be able to help on. I am part of a solar electric boat team from The College of New Jersey. We take a boat up to a buffalo river and race it every year. This year we are designing a new hull. We run primarily two events: Sprint ( a 300 m drag race) and Endurance ( a 2 hour race in which the most laps is desired). Building a hull kind of runs into a problem here. The endurance event is worth more points and usually speeds of around 5 mph are kept for the 2 hours. Beings we run off of only two batteries in this event efficiency is vital. During the sprint, speeds of around 25 mph are the goals. Last year our boat was a deep v towards the bow more and this displacement hull kept us from ever getting on plane in the sprint event. The hull surprisingly did not perform that well in the endurance heats either, but I think
this is dude to our larger weight. The boat is usually around 17 feet but can be smaller if that is more optimized. I was wondering how you thought a cat might do in this type of application. I was wondering could it get on plane or would it at least do well in the sprint portion. I am assuming it would do very well at speeds of the 5 mph but I was wondering how you thought it would do at these lower speeds and its efficiency. We currently have a mono displacement hull and it can not be modified between the two competitions. The length of the craft may not exceed 19 ft 8 inches and the payload last year was around 400-500 including hull and all components, but will be drastically reduced this year with a much lighter hull and most steering weight will be gone.
DRIVER =150,
MOTORS (SPRINT) = 60,
SHAFT/MOUNTS = 60,
BATTERIES = 90,
STEERING 15,
ELEC = 30
And during the sprint we start from a dead stop and go 300 meters so time to get up on plane is important.
I have been investigating a cat with a hydrofoil involved that you could change the angle of attack so it could help us get on plane in a sprit race and be changed to reduce the drag in an endurance race. Your posting about hydrofoils was very helpful was and I would like to know more about hydrofoils and if you think it would be feasible and advantageous to use it on a project such as this.
Our website is http://www.tcnj.edu/~solrboat/solbo04.html
Any opinions would be greatly appreciated.
Thanks for your time,
Brad Lynch","2004-08-04","Brad Lynch","nopswd"," ","lynch10@tcnj.edu","0"
"28","684340","10","Re; model rocket boat||684340","Hello,. Mr.Alan san
My idea is proposed to research of your model rocket hydrofoil. It thought it impossible to carry out radio control for the injection time for about ten seconds, and the SHUPURAMARU type hydrovane with sufficient stability is adopted by the main part of a rocket supported to the catamaran. It is hydrovane experimental ship of a free flight. Refer to the appending illustration. It is necessary to manufacture underwater with an aluminum board etc., and an AOA angle needs to ask for the optimal angle in an experiment. Since it is high-speed, it is important in the case of an experiment to experiment on that people are not in the circumference or safety carefully enough. As mentioned above, please make this reference and summarize your idea. Above","2004-07-25","yoichi takahashi ","nopswd"," ","skyex@triton.ocn.ne.jp","0"
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