Hard starting Yamato 102

[BillCNC]

Thanks Bill for the excellent info on ethanol. However, ... I have a feeling finding the stuff here in SoCal might prove to be quite a task.

[BillCNC]

Testing for ethanol is easy. I have a marked tube I got from Aircraft Spruce - add water to the water line (about 1/2"), add fuel to the (about 3" near the top), thumb over top of tube - shake - let it settle in for a few minutes. If the clearly visible line betwixt fuel and water is HIGHER than the original water fill line, you have fuel with ethanol.

So. Cal is gonna be rough to find clean fuel. Try a marina, as in on the water marina. Yeah, aviation gas is ethanol free but * technically* the Av gas supplier can not sell to non-aviation users because Av gas has a tiny bit of lead in it.

Bill,

I'll have to check into that tube. I drive by Aircraft Spruce a couple times a month.

Thanks
Bill

[G Stillwill]

ust some thoughts after reading through the thread. Early hydros were never designed for air traps and by adding them it upsets the lift in the boat causing the back to lift and the prop breaking loose. If your running the prop that came from Japan with the motors they are not surface props like we race but they are designed to run deeper in the water. Also if your driving the boat like in your picture your way to far forward letting the back lift also. Find a three blade racing prop and go from there that should cure a lot of your problems, have fun.

[ZUL8TR]

air traps on old designs

ust some thoughts after reading through the thread. Early hydros were never designed for air traps and by adding them it upsets the lift in the boat causing the back to lift and the prop breaking loose. If your running the prop that came from Japan with the motors they are not surface props like we race but they are designed to run deeper in the water. Also if your driving the boat like in your picture your way to far forward letting the back lift also. Find a three blade racing prop and go from there that should cure a lot of your problems, have fun.

Sid hydros, Swift hydros and other early designs had long traps in the mid 50's on. I raced a Kelly Wetback (a mid 50's design) in 20ssh and 25ssh in the 1970's that per the plans had short traps but I added long traps from sponson to the rear and it ran great with no back lift you describe and ran with sponsons clear even in the turns amd great speed. Bill's hydro is very Wetback like in design

Here is Swift hydro from the cover of Boatsport from Feb 1958 with long traps

http://www.boatsport.org/BSC/c65.jpg

[S Henderson]

air traps

My DAD'S 1954 swift hydro had long air traps.

[G Stillwill]

I really wasnt talking about the real race boats from back then like the Swifts,Sids and the Hal Kelly boats I was referring to the boat that were in popular mechanics mags you could buy plans for. I thought Bill mentioned his was a titan and I cant see how you can tell from a picture of his boat that its like the Hal Kelly boats without measuring the lift, deck angles and the design of the bottom. I been around boat racing since 1953 so I do know what was ran back then.

[BillCNC]

I thought Bill mentioned his was a titan and I cant see how you can tell from a picture of his boat that its like the Hal Kelly boats without measuring the lift, deck angles and the design of the bottom.

G Stillwill,

It's a Super Spartan, the bigger brother to the Tiny Titan. The Tiny Titan was 8' and the Super Spartan is 10'2". It is extremely similar in design and dimensions to the Wetback in fact, ... you could almost say it's a knock-off.

Bill

[BillCNC]

I have been watching the last set of videos in 1/8 of real time and the sponson's are up and flying 90% of the time which is new, so I'm wondering if I can get them higher once the air trap is shaved down a little.

It seems that if I can get the air to release around the back 20-25% of the aft-plane that will let the transom down a little which should relieve some of the force pushing down on the sponson's from having to much lift at the transom.

Does this sound correct?

Also, ... What do you think about making a jack plate for my motor height adjustments, ... it will also bring the motor 4-5"or so inches further back?

Bill

[BillCNC]

Testing for ethanol is easy. I have a marked tube I got from Aircraft Spruce

Bill,

Is this the critter?

http://www.aircraftspruce.com/pages/...oholTester.php

[ZUL8TR]

old boats

I really wasnt talking about the real race boats from back then like the Swifts,Sids and the Hal Kelly boats I was referring to the boat that were in popular mechanics mags you could buy plans for. I thought Bill mentioned his was a titan and I cant see how you can tell from a picture of his boat that its like the Hal Kelly boats without measuring the lift, deck angles and the design of the bottom. I been around boat racing since 1953 so I do know what was ran back then.

Well it sounded like you ment the hydros back then. My work with the Wetback when I saw his boat thought it looked like the Wetback type. I still think the traps will help him once the rig is set right.

[ZUL8TR]

Traps

I have been watching the last set of videos in 1/8 of real time and the sponson's are up and flying 90% of the time which is new, so I'm wondering if I can get them higher once the air trap is shaved down a little.

It seems that if I can get the air to release around the back 20-25% of the aft-plane that will let the transom down a little which should relieve some of the force pushing down on the sponson's from having to much lift at the transom.

Does this sound correct?

Also, ... What do you think about making a jack plate for my motor height adjustments, ... it will also bring the motor 4-5"or so inches further back?

Bill

Bill

First trim the traps as I previously noted that is make the trap zero at the rear but trim in a straight line from the rear of the sponson to the rear zero point. Then we look at the ride and if needed trim some more. You are going to have to get in the rear and just do straight runs, let's get the lift right then the turns are next. We do one thing at a time.

Forget the jack plate, I believe the hull will ride right with set up and prop.

[Bill Huson]

Bill,

Is this the critter?

http://www.aircraftspruce.com/pages/...oholTester.php

Yes. Tube is plastic so don't use carb cleaner on it.

[bill van steenwyk]

I certainly agree about only changing one thing at a time. All you do is confuse yourself if you try to do more.

I had a Swift "Big Bee" in the mid/late fifties. I seem to remember the air traps on that boat went ALMOST all the way back and the were basically non-existent the last 4-6 inches or so. This could be something you might want to try DOWN THE LINE, if the other suggestions do not get you where you need to be regards lift and air under the boat.

For right now stick with ZUL8TR's suggestions, as the air traps are his design and suggestion, and seems he has some previous experience with a similar design boat as your in his past.

George's suggestion about props is good also, but keep it simple for now, one step at a time, and as previously suggested try to get the boat in a proper riding attitude with air trap depth and motor set up. There are many props out there for you to think about a little later, unless someone reading this might have one they want to let you "try and then buy" if it works.

You are new to the feelings that you are experiencing, and it take a little time to figure out just what you are feeling in your knees and seat of the pants means, when you make these changes. Sometimes what you may think is a "wild ride", almost ready to have something bad happen, is really nothing more than the boat getting some air under it , getting "free" so it can "air out" and get moving. Other times, you might get wet with very little warning, so the practice you are following to video your practice runs and then post here for advice is good as you can get.

If I had to try to describe just what a Hydro feels like when it is "aired out" and really moving based on the power on the transom, an old racer from here in the midwest (who has since gone to the big boat race in the sky) named Emmit Holmfeld described it this way. "Its just like floatin' on a cloud", end quote. If I would add anything at all to that description, it feels like you are on a bubble of air and you can feel the boat rise out of the water and then just stay/stabilize on that bubble. Kind of like riding a motocross bike or something else that can hurt you if not careful and use your head.

That is when you want to be really careful, as you are getting close to the point of possibly getting wet. A fine line, but the good drivers can hold it there with the throttle and body movement. As has been suggested by others that are helping you, you need to get back in the boat some so you can experience that feeling to help you learn what is happening with the changes you will make to the boat and setup.

Good Luck.

[BillCNC]

Last night it was 36* out and I planed down the air trap pieces when it wasn't raining. Got it done and covered but I am not able to go today. I'm shooting for tomorrow.

Anyhow, the spark plug indexers showed up this morning, but to my surprise, ... they gave me two packages instead of the one I paid for, ... looks like I will call them on Monday to see if they want to send me a return shipping label or not.

I installed a pair of .064" indexers, and it looks like these ones will index the plug and recess them a tad, a win-win.

I'm going to toss the motor on and get the height and angle dead on, ... 1-1/4" x 0*.

[BillCNC]

Bill,

I was thinking of getting a prop and need to replace the 16mm shaft with a 9/16 shaft. I'd like to do that during the down time this winter. I was planing on going over this motor and giving her a nice cleanup and polish so when it comes out again around the end of Feb, ... she'll be all dolled up.

I am familiar with the floating feeling, ... I used to race Speedway bikes and that's pretty much having a motorcycle drag you around while your standing on a steel shoe. Remember Gumby, ... slidding on one foot?

What was happening was the back end getting out of control, ... it was wagging.