borristhboxer

Well Guys i thought it might be time to give you another update to the changes done so far..
The engine cowl has been finished and primed, andI have put all the radio gear back into the boat so now its testing time.
The cowl looks fantastic and pretty close to the boat it's meant to be copied from, well it should the person that built the Gp hydo in the picture also did most of the work on this boat and also made the cowl
I tookit down to the pondafter doing a few checks at home to see what it was like on the water..
After trying to reset the fuel mixeture since the motor has been out of the boat a few times the mixtre screw was removed during 1 of the test fittings of the engine so its needed to be rest oh well not to hard i guess. I dropped it in the water and ran it for a little, bugger the drive dog let the prop spin.. after waiting for i to float back the drive dog was checked and adjusted before a second hit onto the water, ahh much better but still not good. Just seems with the new drive that i need a little more time on the bank setting the skeg into the right postion and getting a few more buggs worked out. The boat had no leaks and sat really well on the water, after checking it on the scales its just a little lighter than the stock Elam boat so I was pretty pleased with that
The center of gravity it about 3 mm back compaired to the standard boat but once i adjust the skeg it shouldn't be to much of a problem. The control boat now has a carbon fibre lid over it to keep out some of the water and also carbon fibre was used in the cowl and in the engine bay and also the transom to help strenghten the boat.
Once the setup is done and im happy with it ill record it and put it onto Youtube then it's time to repaint it into the correct colours

borristhboxer

Hey there took it to the pond today for another crack and took the video recorder with us.
Had a mate of mine do the video footage while i ran it on 15% nitro to dial it in so more..
what do you think?
[youtube] http://www.youtube.com/watch?v=glqVzCpwlKU [/youtube]
i know the paint work isn't that great but i want to run it a few times before painting.
i was thinking of going to a 40 x 3 blade prop or a little bigger 2 blader and adjusting the skeg so it dont lift as much for more top end speed

amax

what prop do you have on it now??
Some negative pitch on the strut would definitely help hold the bow down a little more.
Looks Like your having fun which is the important part..

borristhboxer

I'm running a x440 prop at the moment, but yeah your right the strut needs a little negative on it..
It wasset in a neutral postionfor the first time on the water just to see how it went.
If i up the nitro it would make it a little more responce? or would it be better to put a 3 blade prop on it?
Im looking for a little more responcive acceleration and a little more top end speed.
Also whats the best why to find out what speed its doing, like which GPS system is the best, might even get a camera for some on board vision

borristhboxer

Can anyone give me an idea?
yesturday i took the boat to the pond for a little bit of fine tuning and trialing..
I runa normal 40mm prop but tried a 45 and 50 mm prop just to see how it would go.
Both of them took off really well and got the boat up onto the plane really easy but then it just wouldnt go any faster..
When i use the 40 mm prop i can throttle up and do max speed up the straights and have full control but with the 45 and 50mm props it just didn't want to happen
I'm running it on20% nitro, ifi up the nitro would that help or would an adjustment to the skeg be better?

Hydro Junkie

I think your larger props are too much for your engine. Another posibility is that you need to richen up yourcarb setting as you are putting a bigger load on it and with the available fuel there isn't enough power to pull the bigger prop. What you need to remember is that tuning a boat is a balancing act between engine, prop and pipe so if you change one, at least one other will need to be changed as well. Something else to consider is will the hull handle more speed? If you get the larger props to work, you may find the boat upside down

TCHedOff

Boris,

I've been following your thread.... glad you finally have it on the water.

One thing you might want to think about.... watch the rear of your boat in your video and compare it to other hydros running. Even when your going fast, it seems heavy in the butt/sitting deep in the water. At some point, you may want to consider widening and/or lengthing your rear tripletts (is what I've seen 'em called). That should get your heavier-than-designed boat (engine) up more out of the water and riding ON THE WATER. It'll also help address the nose-up running attitude (especially evident when you get on the throttle).

It should be easy enough to test this by making some temporary foam or balsa additions onto your existing tripletts to see if you get a difference and attch w/doublsided tape.

Adding neg strut will help, but it's a bandaid fix for what I think is the real culprit.... and it wont get you any faster. But getting up on the water will help your speed. Just my thoughts.

I owned a Miss Bud 1/12 and the aforementioned mod was something I thought might be necessary if I converted up to a .21.

Hydro Junkie

There was no such thing as "triplett" per se'. The rear of the nontrip, as the side is called, has the little wing or "tiplet" and the rear sponson or shoe. I do have to agree, the boat is dragging it's transom and is very much tail heavy through out the video. I also noticed that the boat tended to try to fly at the front, again a sign of an unbalanced condition. As mentioned above, you may want to add some additional depth and /or width to the shoes to support the back of the boat while running

joseywales

Ditch those rear tiplet's,water dragers. By doing that,should free up some more speed on your boat Also try a 42mm prop,that might be the ticket prop for your boat. The wife has the same hull as yours and its driven with a CMB.21 RS REDHEAD. Really a handfull to run too. That has a 42mm prop on it.

Hydro Junkie

Has she gotten past half throttle with it yet?

borristhboxer

Hey there guys, took it to the pond today after reading what you had written to see a few things...
The water was nice, no wind at all but just a little ripple on the water but perfect for the hydro's to play
I ran the boat on 20% nitro lowered the strut, Major plus, it lifted the bum out of the water and it sat perfectly on the water
I gave it some full noise action and it really was going well, the adjustment of the skeg makes it more flighty but then again it looks really stable and in control when its on the water.
I ran 30% to see what it was like and it was a little better, it was more quicker to respond but i couldn't really notice if i gained or lost any speed, think some tuning might help.
I put the boat onto the scales to see what it's weight was race ready, 2250 gramsor just under 5 pounds now i need to know the weight of the standard boat which I'll find out tonight..
I was going to run a bigger prop but saddly the drive shalf let go so onceI have new partsit willbe back on the water and doing it all again.

joseywales

stock weight is about 4 pounds. Try some 40 or better yet 50% nitro. You'll see a better performance..

borristhboxer

G'day everyone I have been doing some work since breaking the drive shaft.After getting home from a holiday I stripped it down and started to repaint it.I also put it onto a digital scale before starting along with the standard boat, both race ready. As you can see it's not that much difference between the 2 boats. I ordered another prop to try, 42mm but I'll give it a go once I'm back up and running again.Anyway the paint is coming along rather well, the boat was re-primed, base coated in white then top coated in white on the bottom, yellow on top before spending sometime masking up and doing the flame work.Now its dry I've masked it up again for the black around the window and front conard wing. Hopefully it will be painted tomorrow then I might start putting it back together again. I've spoken to someone about doing some stickers for me, so hopefully they will be able to do them to finish it off Once it's all back together I'll upload more pictures

borristhboxer

Just letting you know that i painted the black and have put the stickers on....
now im puting everything back together and going off to the pond

TCHedOff

borristhboxer

Hey all, just letting you know that last night i took it out to the pond for a few laps and a good race against my cousin..
He has an electric elam running 5s batterys about 5500mps set at 80% power with a stock prop.
I was running 42mm prop and 20% nitro, both boats went really well and looked great on the water
had a friend record it so it's on youtube http://www.youtube.com/watch?v=4fIo1u9yN_E
see what you think and let me know....
Getting closer to being dialed in and just about ready to go down to the race track for my first meet

borristhboxer

Well i did a good few hours of testing on the weekend, ran different prop's, skeg/strut height and some tuning all worked really well
Just after some advice on different video camera to put on the boat and also what is the best gps should be used to find out how fast its really going?

A few video's are: http://www.youtube.com/watch?v=EzqtE...eature=related

http://www.youtube.com/watch?v=_nVIspYECIk After this run I was pretty happy enough to say itsabout as good as it gets

TCHedOff

Ever considered just setting up bouys at a mmeasured distance, used a stop watch and some math? Old school but does the job.

borristhboxer

Hey guys just after some advice..
After a minor problem, the flywheel was free spinning I noticed the collet was broken.. ahh the love for a hydro
anyway have them fixed, test fired the boat and all good Oh and a birthday suprise was a a 1:12 proboat Formula Boats.comwith the.18 in it sweet!!!
I'm looking at trying to lighten it up a little maybe run some higher nitro and get it going a little better...
The servo's in it are okay, i have replaced the original ones that got wet a few timeswith cheap ones mg995 YUK!!! (they jitter all the time)then back jr sports servos now i have ordered some light weight hitec ones feather ones i think they are called to lighten the back of it up.
Which servos are good and why? most of them are about 32 grams to 62 grams which makes a difference in the back of a boat!! but the feather ones are 8 grams big difference, even if i use if for a throttle servo!
Another 1 is im getting confused some poeple say run high nitro, others dont. i spoke with the hobby place where i get the fuel from and he said well unless you rebuild the engine, change the timing its not going to work and the motor will last only minutes before it explodes, really how come?
I watched a few jae riggers getting around and they scream!!! small engines or big ones they scream, I watch one on youtube with an engine like mine in it and it was so fast and the sound!! i'd like to know how to get my engine doing the same..
Pipe length i was told not to pay to much attention to it being 8.5 inchs from glow plug, a short pipe is for revs and long pipe is for torque so im a little confused so to speak....
The boat goes well but i would like a little more, think the speed demon is coming, should i try a few engine mods or replace the motor for another is the last resort...

Hydro Junkie

The first rule of thumb you need to remember is that most of the guys that work in the LHSs don't run boats and don't have a clue. That being said:
Small engines are notorious for loving the higher nitro fuels. They will run on lower nitro but normally not as well. Something else to remember is the higher the nitro, the shorter the run time
Pipe length is something you need to look at as you want a balance between power and speed to make launching and cornering as simple as running in a straight line at WOT
The drive must be tuned as a unit, meaning prop to hull, engine to prop and pipe to engine. Too much or little pitch or lift will affect the boats ride and engine load. An overloaded engine will never "sing" like you want while an underloaded engine won't last long. At the same time, as already said, the pipe length and shape will affect the engine's RPMs as well as torque. It's all a balancing act that you need to decode to get the boat to do what you want

borristhboxer

It's been a while since an update was done so here goes
I went to a race meeting and spoke to a few guys at the club, they hooked me up with some 65% nitro to try
They told me to tryodonnel purpleplugsor kb plugs.I waited for a good dayand went down to the pondfor some laps to try it out
http://youtu.be/m6nUYBToIYY this was my first run.
I still had the old os8 plug in it and you can tell because it burnt out towards the end of the video
http://youtu.be/jFZPAd5-wkQ This was it's second try with the purple plug.
I have noticed it starts easier since doing the swap. Before going out I did richen the fuel for the higher nitro then did a few laps on a lower nitro to clean it out before going home and doing a good engine clean down like I normally do after each run. I think it went okay

rcguy1411

nice build just read the thread from start to finish

borristhboxer

Well today was another day on the pond, fantastic weather & calm or glass water.
Went out did a warm up few laps on 30% and the boat was really loving the smooth water. I brought it back in and richened up the needle for some 65% nitro and sent it out on the water again, all going good. I will say this I didn't see any difference between the fuels!!. going from 30 - 65 i just couldn't see it.
SoI brought it back in, leaned it off a little thinking it was to rich and went back for a few more laps still didnt see any improvement...
thought to myself ahh who caresI want to race the brushless elam that had just rolled up. It was arunning proboat metal prop and 2s lipo batteries.
Emptied the fuel tank and reset the needle to where it was before and go ready for some hot laps. After a few laps we sorta lined up for a drag race, He was about 2 boat length in front when we both took off at full noise, By the end of the straight I was close to 1.5 lengths in front before hooking into the corner.
The boat started to take a wide corner before the steering servo decided to snap the mount and straightened the boat for the bank at full noise. I turned the control off hoping the fail safe would kicking, but it was too late.
Hitting the bank and a few rocks it got air-born at about 50 mph After the landing I ran around to see the damage. The rudder was bent and the servo mounthad broken away from the tray it sat on. It had scratched a bit of the paint & gel coat off the sponson, but thats no drama to fix, Also noticed the carb was loose and didn't know if that wasfrom the crash...
Oh well its all a learning curve. Time to ordera new turn fin and fix itup.
Just wondering now ifI move the prop closer to the transom or move the rudder a little further back to allow for better turning.
The picture is an older on when it had a rudder on it, just to give an idea. I'm thinking it would be easy to move the prop forward but how much would that effect the driveablity of the boat?
or would it be better to move the rudder back a little?
At the moment the rudder used to finish before the prop started, like even with the end of the strut. The corner at full speed was big as you could see from the video's before. After driving my normal 1:12 hydro's then driving this i'd like to see if i can get it to corner a little better any thoughts and ideas would be great

Hydro Junkie

I would keep the rudder as close to the transom as possible. The further you go aft, the bigger the boat will behave. If you move the rudder back 3", the boat will act like it's 30" long rather than the actual 27". I would look at either fabricating or buying a beefed up rudder servo mount that can handle the stress as well

wilsonreef

Good informative thread...good job.