eengler

A small update, the boat has been to the lake 3-4 times only. Right now it's 65.2mph with the strut at dead flat with the sponsons. I am running an SS/Hotpipe 2.5 inch coupler / a W2716Round from Dasboata. Doing 2 on the low and 1 on the high. I believe i can mess with the carb a little bit more (lean her) becuase I still get residue from the hotpipe. And change the rudder to a "knife" rudder from Insane. I might be able to achive 1-2 more mph if I do these two things. CG is set at 34.14% on empty tank. The 65.2mph was with very little gas on the tank. WHAT ELSE DO YOU SEE, WHERE I CAN IMPROVE? WALLY????? please....

eengler

These are the pictures to the CAT! I also ordered the 2 and 5/6 hotpipe coupler, just to give it a shot.

martno1fan

I allready mentioned try 1/8 to 1/4" up above sponson bottoms,thats roughly where wally Tahoe has his at i believe?.Also get rid of that transom piccup and use the ones in the rudder.
Mart

PEERPSI

I'm finding with mine that about 1/2" above the sponsons is the best speed, highest RPM's. Try moving up from where you are a 1/8" at a time and 1/16" moves once you're close. Ditto on the rudder pickup. Just be sure you're getting flow. I fine mine clog easy.

What's your exhaust distance, centre of band to joint of exhaust header flange and exhaust port flange on the engine?

PEERPSI

Just took another look at the pictures, looks like you're running quite a bit of positive tilt on the prop shaft. Try more neutral. I find just one degree, negative in my case, keeps the bow down and prevents blow overs. I use a protractor from my high school math set with the boat on a table or other flat surface to gauge the angle accurately.

Scott Schneider

Go to the ABC 2716-20* rake. Round ears with cupped tips at @ 5.2/5.4" ......

martno1fan

Are these speeds with the cowl on or off? is it a full cowl or cut down one?.I know some of the guys running the cut down ones do some mods to the transom on these cats to allow air to escape quick when running.You could also spend some time sharpening up the edges of the running surface at the transom that will make a difference too as it allows water to break free of the boat when shes running.Also spend some time making sure the running surfaces are true and flat etc.
Mart
heres a pic i think these are Wallys boats give you some idea what i mean lol

Body Guard

Hi,
I've seen some difference in speed when I wax the bottom of the hull. 1mph gain at least.
Just a little something that might add one more mph to your current speed. Congrats.
Good luck.
Latiff

painman

You had mentioned that the boat was running wet, try moving the strut up about a 1/4" and leave netural. Just test and TEST; The 20* rake will make the boat faster, if your motor has the torque to spin at same RPM.
Also as mentioned lean, and check plug, I am more at the 7/8's than 1 on the high end. You might try camp fuel and av mixed 50/50.
Where are you getting your IV bags?

Good Luck and Thanks

Randy[sm=shades_smile.gif]

eengler

Mart: yes my cowl is cut and the boat has transom windows. Boby Guard: Yes waxing is a good idea and using "rain-x" also too, i'll try that! Peerpsi, I find that when I raise the stut my boat "attaches" to the water and becomes very wet, then i feel the torque steer (do you think i might have raised it too much?), as far as the quickdraw pipe they are "set" there is no "distance", just the 2.5 inch coupler. I actually do not have a problem with the boat "blowing over", it has never blown over, In fact I want it to ride MORE LOOSE. I also have 3 water pick-ups, the rear one and the two "flush sponson mount" under the boat from dale pynernberg. At first I only had the "flush sponson water pick-ups" but they don't pick-up enough water, so I added the rear one. (I really don't want to burn the engine). SCOTT: As far as the ABC2716R rake 20* and cupped, why do you think that prop is better? THANK YOU GUYS!!!!!

Ron Olson

My Feedback: (1)

Yup, those are Wally's boats. I know, I took the shot. If I didn't take it, somebody did at the same angle!
I've got one from the same event, his Aeromarine that he loaned Carlo and Mark Grim at the record trials this past spring.
Waxing the bottom won't help. Wally sanded the bottom of his of his Drag Cat, at least the last couple of inches as the boat didn't run on that much at speed.

eengler

Yes, I have seen these pictures before. Judging by these pictures, his strut is flat and not much more above the sponson. It looks like he is from 1/8 to 1/4 of an inch above the sponsons. My rudder is a "no water pick-up" rudder to reduce drag, pick up rudders are thick. Remember I will probably buy the "knife" rudder blade ($85.00) that jeff from insane builds, he builds them from an actual hardened steel knife and then cuts them like a rudder. THANKS, KEEP IT COMMING!!!!!

martno1fan

First thanks for posting the pic of the sprintcat Ron i knew you took those pics,i couldnt find the sprint one lol.Eengler first dont wax the bottom the boat will stick,do as full size racers do and sand the bottom using some fine wet and dry about 1200 will do or a scotchbrite pad(fine).Piccup rudders are as thick as you need them to be,i have one thats thin enough to cut paper and does.Transom piccups are fine on a fun boat but when your looking for all out speed its not a good idea.I think i did tell you Wally has his strut up 1//8-1/4 as the pic shows .To thin your rudder blade all you need is a belt sander fixed in the vice and some gloves,press her down hard on it till its as thin as you need,be sure to do both sides evenly .By the way in the pics your transom doesnt show any windows which is why i suggested them .By the way if your flush piccups dont work theyre in the wrong place,positioning is critical especially on a cat.
Mart

Ron Olson

My Feedback: (1)

Wally has a flush mounted pick-up in the rear left sponson. They're a little hard to find right now but you can get pick-ups that get the water off from the roostertail.
Wally was using an H-50 prop reworked by Chris (Dasboata), a Suicidal modded Zenoah and Hot pipe.

Dreamin Hemi

Woah, clamp hand held power tools down in a vice...no way man. It is my strongest recommendation NOT to do this. How do you plan to keep it running?Tape down the trigger? What happens when it falls out of the vice because there is no designed way or safe way to clamp and it continues running? See any issues here....I see pleanty. Even with gloved hands your setting up for injury. Iwould be all over that student in my class if I sighted that and probably reprimanded him for doing such a thing. If you don't have the proper tools to do a job safely, than it's my professional opinion that you don't do it. Easier to find someone else with the proper machines. Simply take it to a tech or high school and their metal shop should easially be able to do it for free.

Usually I keep these kind of opinions to myself, but when it comes to safety, no "toy" is worth bodily injury. Falls under the same line as using the right gear to retreive a stalled boat out in the lake. If you don't have a proper means to get it, your not ready to go out.

Sorry mate, had to say something.....

martno1fan

Well it has a push button to keep it running and its never fell out of the work bench so far ,i use wooden workmate type table to hold it maybe i should have been clearer.I also have a custom built table to hold one as well as my router,no big problem at all theyre made for this job.It didnt surprise me you would chime in Scott its the teacher in you but ive never had an injury with any power tools in 30 odd yrs of working with all kinds of machines both at work and home.I dont see any safetey problem using a belt sander this way and using your hands to apply pressure to the piece your working with,its no different than using a sanding table .In my experience common sense needs to be applied with any machinery but what ive suggested is not dangerous if common sense is used.You can make a sanding table to utilise your belt sander quite quickly and they work well.Allways a good idea to have a fence or a stop behind the work to stop it slipping in case you do let go,we dont want any accidents do we
Mart
heres an easy to build sanding table they work great
[link]http://www.youtube.com/watch?v=oodlRI139-c[/link]

Paul M

Here are the things I have done. None of them are my ideas

1) Scotch brite the running surfaces, don't sand. Be careful of sanding - you may change the shape and really have problems. I f you must sand, use a block so you don;t round the corners

2) Lose the transom mount p/u's - it is slowing you down. The flush mount needs to be mounted as far back in the sponson as you can. I use them. It's not going to burn the engine. Just check for flow. As long as you can put your hand on the head for a count of 2 when you bring the boat in, your fine.

3) The pic looks like the strut is positive but there is no way it can be and you not blowing over so I am assuming that it is neutral. Strut position on the Sprint will be different than on the Drag or the Falcon.

4) Cut windows in the transom - they will make a big difference. The transom can trap air and slow you down like a parachute.

5) You can change the pipe length on the hot pipe. Order a length of Phenolic tubing from Maston's Marine and cut it to lengths. If your at 2.5 now, try a length 1/8 inch shorter and longer and see.

6) Change things one at a time or you will quickly become confused and write down the results

7) No offense to the guys on this thread, but IMO you are wasting your time asking a group of people on here about this cat. Alot of em including me don't even own a Sprint. (Flame suit on)Wally is the last word and has forgot more than most people will ever know about setting this cat up. Talk to the Doctor[:-]

martno1fan

Paul i agree ,but hes allready stated before i believe that Wally was giving him advice so i cant understand why he doesnt seem to have used it no offense meant .I said in my first post to raise the strut same as Wallys ,also it doesnt have to be a sprintcat to know a transom piccup causes drag.If hes waiting for a sprintcat expert to come on here hes got a long wait ahead.I agree try the dock thats where you will find them or modelgasboats .I will have my own sprintcat style hull come autumn.
Mart

PEERPSI

Part of my role here at work is setting up and managing an electrical safety plan for our factory. Now I've been involved in the trades for 30 years as well.

Two things, in most places I've worked locking buttons are banned. Numerous injuries caused with drills, grinders etc.. In one plant we went as far as removing them in existing units.

My second comment would be that most often the serious injuries occur to those with plenty, often decades, of experience.

Safety is an attitude first and foremost.

Like drinking and gambling, working with tools one should always know their limitations. Be they hardware, skill or knowledge.

Also has anyone come up with an emicon that shows the little guy struggling to close the zipper over his mouth?

Tahoe1970

Thanks guys......Ron I run only SS motors , Never ran a Suicidal at the Events.
Paul , Appreciate you saying those nice things

I'am going to try to make this short......Dragcats like the strut almost even with sponsons

Not all sprintcats are rockets , Sad but true.....I have built plenty of them. Out of the recent 5 sprintcats I really only had two of them that broke the 80mph mark.

A few basic Tips :

Strut at least 1/2 above sponsons....thats with boat flat on a table and measure from the table to the bottom of the strut tube.
2716/2 - 15* rake cupped has netted the best speeds HANDS DOWN.

here's a picture of my cat using a flush mount......does not lack any flow

martno1fan

All my hand tools have locking buttons ,nothing elegal about that.All shop machinary has a cut off button as does my sanding table for when i want to use any of my tools in it ranging from a sander,router or circular saw,as i said use common sense.All this aside anyone who cant work a belt sander shouldnt be using any power tools get real and stop trying to come all high and mighty.Belt sanders have been used this way for years in fact you can buy tables ready made to accept them for use as ive described,along with the other tools i mentioned.I think weve covered this subject long enough now.
Mart

Paul M

NP Wally. Wow only two 80 mph Sprints, I really hate it for you. LOL

Always did love that picture of the dragcat. I really think you should post that in one of the airplane discussion forums We should talk soon. Been awhile

On the safety issues, I make artificial limbs for a living. Never take chances with power tools. that's why they call em accidents. I could tell you stories that would curl your hair. There's always some numnuts that thinks he can bypass the laws of intelligence. Next thing you know, I'm makin him a plastic whatever. Hey it's a living baby.

eengler

I trimmed the rear water pickup, changed the coupler to a 2 and 5/8 and raised the strut.... we'll see! Thanks!

eengler

Here are a few more pics, Where the gas bag is located, the angle of the engine, how the cowl is cut, the rear water pick ups, transom windows, where the rabio box is located, how the strut and rudder installed. By the picture of the "flush water mounts" you can tell they are not perfect flush and they are not perfect aligned with the boat. From the looks of it, my rudder it tilted too..... It does not have a stuffing tube, becuase i was in the middle of moving back the engine 1/2 an inch, when Wally told me to send more pics.
So, on paper we have: to sharpen my rudder (or purchase the tapered knife rudder), cup the w2716R, align and flush the water mount to remove the rear water pick-up. THANKS TO ALL!!!!!!!!!!!!!!!!!!!!!!!!

Tahoe1970

I hate to Say this.....But some things are a Mess[] The flushmount is destroyed....it will never pick/up water again ! Your hardware is on Crooked (Not Straight). Depending on how you have the stuffing tube done....thats a key factor also. Steering rod definate NO NO...ect ect

I see too many things wrong for this set/up to run as fast as you want it to go[]

Heres a few of mine and how they are done..............