ORIGINAL: vertical grimmace
ORIGINAL: alfredbmor
There is great literature here to read and involve to practical fluid physics, but the real deal is that the uniflow set up does not work, at least for me. I have tried in different circumstances but mostly because I wanted to stop flooding the carb in a high tank set up. According with the magazine review, the Uniflow will prevent the flood in a high tank configuration, in my tests the flooding with a Uniflow system is worst than using the normal tank configuration, maybe because I was using an enclosed system with a check valve at the muffler line.
In a lower tank the fuel does not get to the carburetor easily, maybe, as has been discussed earlier because of the pressure of the fluids that could cancel the effectiveness of the muffler pressure.
The system works better with the tank level with the carb. Providing a constant flow on the fuel, and preventing the engine from a leaner condition with an almost empty tank.
Our engines work fine with the normal configuration an can handle the leaner condition with almost empty tanks (They can not handle an empty tank with either system
)
It will be good for all of us to hear from more people that have been using the uniflow set up and to hear from their experiences in a level, higher or lower tanks setups. Allanflowers mentioned something very accurate when he expressed that plane manufacturers does not mention the uniflow system and the reason is simplicity and effectiveness. I just wanted to express my personal experience and I am looking forward to hear from some more experiences.
Interesting how you can make a blanket statement that something does not work, when this type of tank is not designed to solve the problem you had.
Your first mistake was to think the Uniflow would solve an extreme high tank problem and your second was to put a check valve on your pressure line! It is amazing how much pressure comes from your muffler line but it mostly bleeds out of the tank because it is not sealed. Increasing tank pressure would only make things worse if you already had a fuel syphoning\flooding problem.
The solution here would be to use a regulator like a Cline. Uniflow is a great system I have not read the article but it sounds to be misleading. Your tank must still be positioned properly. It did not work for you because it was not meant to solve your problem which you would have had regaurdless of how your tank was vented.
The blanket statement comes from the statements described at the magazine.
Definitively it's necessary to read thoroughly the review, the set up I used was following, step by step the procedure reviewed at the magazine.
One more note: There were two different issues on the same magazine covering the Uniflow system, the second one tried to clarify some confused statements made on the first one, I do not remember if it was FlyRC or MAN, as I am subscribed on both, but I would assure that it was a FlyRc magazine.
Maybe I did some mistakes in the set up like you are mentioning, but the author claims that this system works to solve a higher tank set up (they show some drawings) and the use of a check valve, you should look for that review and tell us if it is right or wrong.