Video of Rod flying
Excerpts from email exchange with Ray Vellinga, IHS:
Attached are some pictures of progress so far, she is 14 foot long 4 foot wide and will be driven by a 40 hp 3 cylinder Suzuki car engine via a custom made deep leg stern drive with power transmission via timing belt made from a chunk of yacht mast,
I was just going the buy a 30hp long leg Tohatsu outboard and get the extra leg extension for it but that is not much of a challenge.
I have also acquired a couple electric actuators because in the first instance I was going to make the front foil variable.
I have got the plans for the Sportfoil boat and some other stuff and ofcourse you book is the bible.
My goal at present is to finish the hull, the stern drive, engine installation and some other stuff to establish her weight before I got serious about making the foils.
I am an engineering patternmaker by trade and have recently retired from my business www.strathsteam.com so have almost unlimited
I still have not made a decision yet whether to go surface piercing or canard.
My question for you if I may, I can buy these extruded Ali foils they sell for making wind generators, I have looked at them fairly closely, although they have a fair bit of reverse scalloping on the underside I think they may do the job what are your thoughts.
First up I spoke to the guy with the extruded airfoil sections a few month ago and he answered with this:-
T6061 material standard
Same profile with easier end cap mounting (relates to PVC extrusion you can see on that website)
My weight is 80kg
25mm... deflection and that length I am standing on is 5 foot
And... NO... there is no trickery , these blades are strong and quiet , they do not need solid bar to strengthen , a good heavy wall tube min 50% of the blade . (That relates to use for a wind generator and no there is no tube in it)
I have not made up my mind about configuration but it will be a 4 poster I want to be able to drop the actuator arm of the front foil so I can fold it up towards the bow to make it easy to put on and off the trailer (see picture of trailer)
I have been concentrating on the stern drive leg which I finished machining the internals of the lower drive housing and perhaps tomorrow I will make the front seal carrier/bearing retainer and then the conical cap leading to the propeller hub and maybe begin the SS prop shaft, in one of the pictures you can see a prop I thought may do the job it does not have much pitch but the Suzuki engine can run up to 6 to 7000 rpm and it is a 1 to 1 drive so it may be suitable. I am facing the prop forward.
I had a look at it and a heap more stuff on the photo site in particular found a web site with some good pictures of Bras D OR
so as you can see from the pictures have taken the "plunge" (metaphoically speaking ofcourse I dont need to do any swimming) to run with a similar layout for the foils as the FHE 400, what a buzz that would have been to go for a ride on, especially at 60 plus knots.
The front foil is 8 inches wide across the chord and a total length of 72 inches while the rear main foils are 10 inches wide by 74 inches long with a take off foil that is 48 inches long by 8 inches wide. I reckon the boat will weigh in at around 1000 with me and fuel.
The masking tape shows where the extra struts will go and they will add to the lift aswell.
I have a feeling it will be over foiled but as you said you can always cut them down, my only comment at this point is " there are soooo many variables" I guess you just have to draw a line in the sand and start from there.
I am using 1 inch ply for prototyping as I think I could waste a bucket of money on Ali, I managed to get all the foil stuff out of one sheet of 8 X 4 foot 1 inch ply.
A tiny question for you "am I trying to fly to high to start with" and am I dicing with danger? I am a careful test driver/pilot and will take it extra quietly to start with. I can easily lower the foils at this time and just leave the legs standing above the deck line till a later date.
October 1, 2013
Well the project started in early April and she flew in early October (6 months) much to my great pleasure and relief.
I have been having sleepless nights over the past week fretting over whether it was going to work and finally today although it was still a bit windy I figured it was safe enough to go for a fly so I arranged with a friend to back me up with another boat and took her down to the river.
I had an opportunity to borrow an 8 horsepower long leg Mariner Sailpower outboard which I wondered a bit, if it had the grunt to get her out of the water, to my surprise she lifted out with ease mind you pretty sloppy flying technique to start with and a few unceremonious crashes back into the water till I worked out where to sit and just how far I could lift her out before the prop lost its grip and she nose dived. I havent even dared to think about turning a corner at full speed yet I think my blood pressure would have been off the planet as I backed away from the jetty and the adrenalin was rushing freely for the first few minutes, but there is plenty of time for that yet.
This outboard is a bit daft as all my other outboards you can lock the leg down manually but this one will only lock down when you engage reverse gear so it gets cranky when she starts to hoot along but not much more than about 18 kilometers per hour on the GPS before it looses the plot.
I took a few big greenies over the bow at times and as we don't have a front deck yet, that was a bit uncomfortable but now I know I heaps more about where I am headed I can concentrate on sorting out many more things relating to the whole boat and finishing the set up of the trailer.
I can now understand how you broke your nose when Sabre Foil took a dive at high speed and you broke your nose, hell, it is like you hit a brick wall and then all of a sudden you have an engine running at high power suddenly grips when the transome drops back in the water and tries to smash the back out of the boat as you accelerate forward at a rapid rate.
Anyway just great great fun I can see it being a special summer this year and Wow as you say the moment you lift the hull clear of the water surface she takes off like a rocket.
We must have a long and serious chat soon to get some advice from you as it is doing what I thought it would, in the fact it is "overfoiled", gets out of the water quite quickly and perhaps has too much lift that is to say "it works too well".
I sincerely thank you Ray for your advice, support and your great book.
Here are some pictures of the fitting of the suzuki engine and rear leg.
As you can see I have strengthened the transom considerably as with the 8 hp outboard it was making cracking noises so hopefully this will be much stronger. I have had to put a pad on the transom so I can fold the leg up to one side or vertical for towing the boat down to the river as there is literally no road clearance when it is in the running positon, the vee shape sheet of aluminium which coveres up the water inlet pipe on the forward facing section of leg would have been hitting the wood.
I am waiting on the belt people to run my numbers through their computer to give me the belt tension figures so I can pack the bearings out, then I can drill the holes in the transom, mount the leg properly and couple it to the engine.
I have searched through my junk and found a forward control unit of an outboard a steering wheel, cables , pulleys etc so that is another job that can move on as well.
Notes taken from Rod's video:
Published on Oct 8, 2013.
This is my first attempt at a hydrofoil which came together with the help of Ray Vellinga's book on Hydrofoils, some plans entitled The Sportfoil along with endless hours of looking at internet info and watching Youtube clips and then rolling all the ideas together to come up with what you see.
Her name is TOPPY which is Japanese for flying fish and there is a fleet of Boeing 929's Hydrofoils that work out of Kagoshima all called TOPPY 1 to 8 that were built under licence by Kawasaki.
It is by no means finished as it is powered by an elderly Mariner 8hp long leg outboard which limits its flying height at approx. 8 to 10 inches (200 to 250 mm) before the prop comes out of the water and causes her to crash back onto the surface. I was amazed at how easily she gets up on the foils and flies and on this day we put a second adult on board along with an extra 40 litres of water which just made it go faster as one had to apply more power to get it to fly and hence higher prop revs with increased speed but certainly no even close to flat out.
The next step is to fit it with an old Suzuki Alto car engine and a specially made deep leg stern drive which utilizes a timing belt drive down inside a chunk of yacht mast with a forward facing prop.
At present it will do about 25 kilometres an hour and I think it is over foiled as it creates too much lift with the boat 1200mm wide (4 feet) and 14 foot long the front foil chord is 200mm wide (8 inches) and the back foil the same for about 500mm (20inches) but then the foils going out to the struts widen out to 250 mm (10 inches), as I make changes and additions I will put up some more video clips.
November 7, 2013:
Here are some progress pictures of what I have been up to,
I epoxied the inside of the hull where the engine fits and painted it so I could fit the engine.
Made a sort of wind screen come water deflector and incorporated the steering box mount and
will be the dash board for switches and gages.
Installed the steering wheel and cable but yet to hook it up to the rudder shaft.
Installed an old Suzuki outboard remote control and made a cable adapter for carby cable.
Brought together a new (old stock) muffler to the engine.
Fitted the wiring loom but not wired to anything yet.
Bolted the leg on and aligned the drive shaft, although still temporary as the transmission people
have not come up with the tension figures for the belt yet. ( hopeless bunch,manufacturers that is)
Cut all the keyways and fitted the HRC coupling.
Ran the engine for a little bit as no cooling system yet to see how quiet the muffler was.
As you can see I got the wiring done enough so I can start the engine without using jumpers .
I have pulled the steering box back out and spent about 2 hours on it replacing the substandard plastic bushings supplied by the Indian manufacturers with some of my own with much higher tolerances.
I have been agonizing about the problem of ground clearance on the leg and foils when the boat is trailered, trying to think up some method of either getting to leg to clear the ground and had ideas of scissors type jacks or hydraulic ram etc. but a friend of mine said why not winch it up ( the man is a genius) so with considerable thought and testing I came up with a system that can pull it up to give me plenty of ground clearance when I tow it down to the river then winch it up a bit take out the chocks and lower it back down to launch.
I can lower the foils right down to the design level and still not have them hit the road but it may be a while before we I get to drill some more holes and drop them to try it could be a bit scary
I am yet to try it but I am confident it will work although I wish I had bought the bigger capacity winch as I had no idea I would use the little one for such an arduous task I think I shall replace it with a higher capacity, lower ratio one.
Anyway there are many little sorting out jobs to do now, I finally got the figures to tension the timing belt so that has been done and it seems to run almost totally silent.
I trust you are well and speedy is looking good i thought you might like an update on progress.
The weather has been too cold and windy of late and I have been taking it a bit slower while recovering from my little health issue I had finished installing the car engine in the boat along with the leg, steering, electrical wiring and other associated equipment and took it out for a test run today.
The weather wasn't the best a bit too windy for a comfortable run but we got in a few good rides.
The major problem in the first instance it the rudder is far to small and the boat just does not want to respond so I could barely turn even with the boat sitting on its bottom.
I shall overcome this problem to start with by bolting a bigger sheet of Ali to the rudder and drop it down below the lowest part of the leg so it is in the clear water stream from the prop.
The other problem was its riding characteristics very unstable by comparison with the outboard.
The reasons I thought I should sit much further up front to compensate for the heavy engine but this was wrong because we are still getting heaps of lift from the big back foil which is tipping the boat forward with the slightest disturbance and she plunges back down with a big splash because the angles of attack get all out of whack.
With the outboard engine it was very stable as the back foil was controlling the front I get the distinct impression I must shift my seating position aft more to the center of the boat which is what you say in your book it is funny that the boat sits well in the water with almost a parallel water line but this I can see is wrong it is all about surface areas of foils in flight and how much lift the generate.
Anyway I wont bore you with my rambling.
We took a video but it only ran for a couple of minutes as the camera battery went flat but here are some stills.
We had a bit of fun and I was happy with the engines power the radiator kept it at a good temperature and the propeller pitch seemed okay you have to give a fair amount of grunt to get up out of the water which I think is due the big fat leg but once you pop up she takes off like the proverbial cut cat although I got fairly wet.
Here are the pictures of the latest modifications.
A much bigger rudder surface area with a bit extra down in the the flow of the water coming off the prop.
Shifted the seat, steering wheel and throttle control back about 3 feet
Made a couple of GOPRO camera mounting points so I can see what is going on during flights,
Dec 5, 2014:
The pictures of the chopper blades look really nice it will certainly be interesting to see how effective they are.
Hey it is really great to be able to talk to you as well Ray I can tell there are so few people who know much about hydrofoils in Australia you give me invaluable inf. and support.
Here are some pictures of the Sportfoil as she is today.
A great little craft easy to fly handles well very very economical, talk about run on the smell of an oily rag.
The name as you can imagine is a play on words relating to the fact the importance of a hydrofoil needing to be able to get it up (so to speak).
I have put numbers on the pictures in case you have any questions relating to it and I was interested to hear your thoughts on a couple of things.
I have spent ages looking at the picture gallery of Bras d Or which has a front foil with wings at 90degrees the sportfoil front foil is 90 degrees but when I made mine the included angle is about 120 degrees.
I downloaded the patent of the man who used to make the bolt on foil kits back in the 1960 and he started out with about 120 degrees but his last design was such that the bottom half of the front foil that was in the water at high speed was a 90 degree angle and then spread out to about 120 for take off and he thought this was really good
Here is a selection of pictures of the craft at present you can see from the black race tape covering up the bolt holes I have lowered the foils by 3 inches to increase my ride height to 15 inches
I have cut the section of foil out that used to join the back foil system through the center in an attempt to loose lift so I could drive it faster without coming out of the water.
This worked I could only get about 28 to 29 kilometers per hour before but now we are up to 34 and the engine is right on its redline so I must get a new course pitch prop sometime I have one picked out.
Important thing at present is to sort out stability problem as I described on the phone which as you confirmed sounded like serious ventilation.
I took the take off wing back out again as it was upsetting my take off characteristics and it really was not necessary as with out it she climbs out of the water quite quickly anyway.
I have raised the engine 2 1/2 inches so there is not so much leg in the water as I got the feeling it was part of the instability problems and was causing drag.
I have begun to modify the foil section already as you can see and I shall do the back ones as well but not quite the same as the Clark Y to start with as that will require some substantial filling to get it right and I may make some new foils but we will think about that for a bit to incorporate the 2 angles in the front foil like the kit set I mentioned.
Anyway important thing at present is to lessen the ventilation problem.