Mark- You wrote that you took the mvgs off a Greg Loehr fish and positioned them in-line - where did he originally have them? Do you prefer the new in-line position, or the original position? I ride thrusters, not twins, but I’m intersted in trying these mvgs. For thrusters would you put them in front of all three fins? Mahalo,
mvg’s?
Mark puts them in front of the back fin only. He has been working in others that will fit elsewhere but I haven’t seen them yet. He was also working on some C-5 type as well.
mvg= multi vortex generator. it’s a take off on the term micro vortex generator, a concept developed by NASA many years ago. in our design we use 2 or more micro vortex generator finlets arranged in a linear array, hence the “multi” term. there are many reasons for this like the net effect of fin volume greater than or equal to fins much larger. plus with lower profile and hence lower shear requiring a smaller base making posible the use of 3M VHB Very High Bond adhesive tapes. NO damage or major alterations to any existing board surfaces. No skin penetration either. Thus you can retrofit any board in the world. i credit my team rider #1 turner lotowycz in jax FL with coming up with the “multi” part of the name many years ago and it seemed to fit perfectly. on my boards with thruster setups i have been putting only one in front of my trailer fin. Kech and Nick Guillarte like this set up too. in fact it was Kech who came up with the one thumb width measurement between the fin and the mvg. John Holeman rides twins so he puts the mvgs in front of each of the twin fins in line and at the same toe in angle. Greg Loehr told me he had been thinking of ways to clean up the flow after it goes through the side fins of a twin fin fish by putting a fin on each tip of the fish tail. clyde beatty, inventor of the Rocket Fish and a Resin Research user, has done this with fcs c-5’s. however, the plugs limit thinness of the tail points, which is a demand mvgs dont make. so Greg said when he saw my mvgs he thought they’d be perfect for his idea. besides putting less demands on the builder he liked the design as it fit with well with his theory of cleaning up flow, which is the principal design feature of micro vortex generators. to do this Greg places them about an inch from the tip of the tail pointed to the nose. i like greg’s setup for tail turns and lippers. that design just goes anywhere i want doing standard twin stuff(bottom/lip/bottom /lip) and it doesnt stall in the flats. the Holeman set up i have only tried once but i think it will be better suited for very rapid acceleration, putting my rail in the face and launching airs. i dont think an mvg is necessary in front of each fin of a thruster. that just seems like too much mvgage. you’d have to be very powerful to control it. but Holeman has that power though he doesnt show it. he has worked with two experimental triple mvgs in front of his side fins. he said he liked it. i dont know where the point of diminishing returns will be just yet, but i believe it will vary from surfer to surfer. m