genesis set up please

[1945dave]

Yep Martin, I think you are right on. Regardless what his actual speed is the known result is high heat.

Dave

[martin]

Your absolutally right running these cheapo motors at more than 30,000rpm unloaded, ive seen to many fairly new fe club members that have these very type motors in Pursuit monos that want to go faster than the 4s set up but dont seem to understand its not as simple as going higher voltage will be faster. Ive tried to explain things as to why but they either dont listen or simply dont understand what your saying, sometimes it almost sounds to me that im trying to put them off & dont want them to have a faster boat. At one time all you could smell at the lakeside was that horrible electrical burning smell where they were melting down esc & or motors.

[J.Calway]

Its true i do like the speed.... 90kph today.. will it go faster in fre thansh water...? Its not a reliable boat and w ill be lookito change. would a more honest ,speedy than the birdie 200 a make a difference or should i stick to lower kv motor?

[1945dave]

Okay my Ausie from the land down under friend. First the Genesis is a perfect boat for your interest. For some reason you are saying you will change the boat or the speed control but the only thing you have got to change is the motor. If you do that, as all of us have tried to tell you, you will be happy and you will be ble to hit 100 kph.

Do it!!!

[Prop-a-Gator]

J, I like the speed too!

Early on, I too tried a high rpm setup similar to yours in my Daytona (Genesis hull) with a Birdie 200A. My setup yielded a slightly lower unloaded rpm than yours, but still 45K+ rpm! I don't know what prop you are running, so I can't tell what your current draw would be, but I thought I was well under the current capability of the Birdie. (130ishA calculated, actual amps?) It was really fast for about 4 passes. Now the Birdie is stinking up a landfill somewhere and my hatch has some battle scars... I now have a FighterCat 16S300A ESC that barely gets warm and an Eagletree on the way to log what's actually going on.

Just thought I'd share my newb mistakes. I don't expect anyone to do as I say or suggest. We all have our own goals and motivations. Just passing along info and hope you have fun!

[limitedr1]

j.c. are you asking if it will go faster in freshwater??? you also state that the boat is unreliable.....the boat itself is fine, what these fine, experienced guys like martin, dave and gator are trying to tell your set up is not reliable. 6s is great for this boat. they are saying that you have got to drop kv on your motor choice if you stay with 6s. or drop to 4s maybe 5s depending on your prop choice. martin is trying to warn you about quality and heat issues you might be having due to your amp draw and rpms on your motor/esc. i also get a sense of frustration here as you chimed in asking for advice and seems to be ignoring it. least that what i am getting out of this thread here maybe im way off.

[martin]

My experience with freshwater & saltwater is saltwater is denser than fresh due to the salt & you get more bite on the prop, not sure if its enough to push amps up much higher. I now only run rc boats on saltwater but ran tethered hydros on freshwater for 40years, years ago i use to run rc nitro boats mainly on salt & boats were obviosly set up for my lake but when we went away to run on fresh lakes the boats was always underpropped with more prop slip on the freshwater & looked slower but were reving harder.

[J.Calway]

ok... i would like to clarify the CG of my boat... do i rest the boat in the a
water ,no batteries, then measure from where the water first touches the front to the rear of the hull then measure 1 third of that from rear of hull ??

[1945dave]

No that would be too complicated. Actually on most other boats you measure from the outside edge of the transom and calculate 28% of the length for the stating point. On the Genesis because the rear edge of the sponsons stops about 4 inches forward of the actuall rear of the boat that is why some guys say 33 percent of the over all length. However, when you do the math and measure corrrectly the balance point falls about 1 to 1.5 inches forward of the motor. You need to remember that this is a starting point. Many guys have their own feel for how the boat should balance and not all knowledgable racers are going to want it the same. A fudge factor too is the speed your boat is setup to achieve. I would venture to say the balance point for the 84 mph Genesis would be further forward than most of us slower guys running down around the mid 50's. Part of that explanation is the fact you need more weight forward at higher speeds to keep the nose down and not allow a blow over from excessive lift. So I hope what you gain out of this discussion is that you need a certain amount of weigth to keep the boat stable. You do not want the boat to ride too wet but if the balance point is too far to the rear the boat will porpoise and maybe blow over. If the balance is too far forward the boat will ride too wet (bow down attitude) and not corner well. You need to experiment to adjust the balance the way you like it best.

Dave

[martin]

If you do have probs with blow overs due to high speeds ( cg needs to be in the right place to start with ) fit an air dam around 2" in from the front of the tunnel. These work wonders on cat hulls either stopping blow overs or just keeping the front more planted.

[JonD]

If you do have probs with blow overs due to high speeds ( cg needs to be in the right place to start with ) fit an air dam around 2" in from the front of the tunnel. These work wonders on cat hulls either stopping blow overs or just keeping the front more planted.

I'm not quite sure what you mean by an air dam. Do you mean blocking off the tunnel close to the front? Wouldn't it add more air resistance? Could you please elaborate.

Jon

[martin]

An air dam is quite common on cats & hydro hulls even Kintec racing sell them for the UL1 hydro, basically its a piece of plastic angle that gets fixed between the 2 hulls 2" in from the front, the edge that hangs down is around 3/8", wind resistance is neglagable over how much you can push the speed on the boat & not lift or blowover. Fluid on this forum one of the most respected fe racers on this forum uses a simple drinking straw taped under the tunnel running at 80+ mph.

[J.Calway]

What is a good rudder saver, as the nylon one keeps breaking at high speed . brass ?

[1945dave]

Ah, how fast? Is your pond full of sticks or other junk. I find it hard to believe water pressure is cutting the nylon bolt. If you change to brass it might be better than steel but it still might rip your transom bolts out the transom or perhaps damage the hull structure itself. Somebody recently showed us pictures on this forum showing what happened to him because he replaced the nylon bolt with a hard metal bolt...lots of physical damage plus a major water leak out on the lake before he could get to retrieve it. I have only replaced my nylon bolt twice in maybe 50 runs. Each time I hit something I could not see perhaps a turtle because besides the rudder I curled my brass prop. I have run through some seaweed that almost brought my boat to a full stop without shearing the nylon bolt. Is the pivot bolt fairly tight? I think I tightened my pivot bolt tight enough that I could run perhaps 45 mph without the nylon bolt whatsoever (just a guess) tighten up the pivot bolt pretty snug and go back with nylon. By the way Radio Shack sells small nylon bolts I believe they call them chassis bolts. 3mm is about right.

Dave

[J.Calway]

Thanx dave.. yer we have a few sticks an such as is a tidal creek . i think the nylon provided is soft , will stay away from metal...