Hello Kris-I was just making a "blanket statement" that seems to me like everyone is trying to make a tunnel boat that looks fast &"zoomie" sitting on the table but making no progress on the water. This could be a controversial subject and some probably will not believe what I say but I don't care . I know what I have learned. I have no desire to get into a big discussion over this. (I'm too old) I do have access to wind tunnel data that was taken from a model of a full size boat and from what I know this is the only time this has been done. I do not own the data and I cannot and will not share the info on an open forum. However, all the aero principles that have been around for years and apply to airplanes, cars, trucks, etc. also apply to tunnel boats. There are no big secrets out there. I will share a couple of facts that may surprise you-maybe not. 1-a tunnel boat is not a good aero design. 2-the deck shape above the tunnel floor does absolutely nothing to affect performance, lift or anything. 3-you CAN NOT CREATE LIFT from the deck of a tunnel boat. 4-the cowling has no lifting capabilities and Kris as you have stated the boats work pretty good without them. Maybe a small increase in drag. A few things to think about.
I have worked on tunnel hull aerodynamics for the past 20 years and it is what keeps me interested in the sport. I have learned many things about these persnickety little boats because I don't accept ANYTHING that I can't prove to myself. Yes I am hard headed. I have a wind tunnel that I test and prove all my boats on. It came with several variable surface texture settings and air speeds but I am not able to set them because they are randomly set by the guy who made it for me. The last tunnel boat design that I just recently finished is called the Taboo MR 300 (MR for Mike Rushing) This was the last project we worked on together before he passed. This boat challenged all my knowledge about boat design big time and I ended up spending 9 years in development (off and on) and 5 molds before I finally got what I originally set out to build. I learned a piece of the puzzle with each change I made. What I had originally set out to do by building the Taboo was to make a boat that was superior to the performance of the Lynx. This is why it took so long to accomplish. So far only two boats have come out of these new molds.
People who run my Lynx and who also know how to set them up
correctly... will tell you that they can actually see the aerodynamics taking affect and working on their boats as they near the ends of the straights while driving them. You will never get this to happen unless you have a boat that is what I call neutral. Meaning the top and bottom of the boat are working together to the same degree "at a given speed". When you get to this magical point, you can push it faster than ever because everything is working together instead of one over powering the other as the speed increases. When I design a boat, I am all over it. Meaning, I am working it from all aspects of its shape, length, width, weight etc. leaving nothing out while trying to get the model to behave in a certain way. All of this effort only gets the initial prototype close to this point because believe me this is just step one of a long project when trying to tame a tunnel boat. The sleek resulting look of the boat is just what works best.
As Kris mentioned in his post about his cowling having little affect on his boat... When a boat is being controlled mostly by its hydrodynamic footprint, then aerodynamic changes may not have as much of an affect on the model and vice versa. This is not intended to be a slam to his model because the Dragon can run hammer down around the track and finish in some nasty water. We have been watching the performance of this boat and agree that at the end of the day, it is a good round track boat. When you get your model performing equally between these two effects (aerodynamically and hydro dynamically netural) is when you can really start to work on subtle changes that allow you to fine tune your model. This takes time and LOTS OF IT! You do not always make progress as it is easy to branch off into what you think is a "fix" to a problem only to learn later that you have been working on an
"effect" the whole time and not the real
root of a undesirable trait.
If you want to design, build and perfect a model tunnel boat, get ready to spend years doing it because if you throw one together and it is the best tunnel boat ever made in its class; you will not need to think that it will ever happen again. If it does, you would be better off using that kind of luck buying lottery tickets because take it from me, you will never make enough money from selling models to pay your bills.
But now to each his own. I'm not knocking anybodies designs or ideas. I think everybody should have their own ideas because that is what makes designing and building and racing tunnel boats fun.
See you at the time trials!
-Carl
