OB Hydro Tuning...?

[_laxmasta2039]

i've got 4 weeks to get my Phoenix running smoothly for the first race of the season, anyone with experience running OB hydros please help me out. can't start 'till next weekend but i've got a couple pre-first run Q's..:

-I got everything in the boat needed to run except steering servo and fuel, and put it in the water- the back sponsons completely submerged, and the water was only about 1" shy of flooding in over the transom into the fuel compartment. im afraid filling the tanks will push it low enough to sink the compartment...i know riggers sit very low in the water when not up on plane but shouldn't there be a bit more space between the transom and water line?

-there are some square metal plates curving up off of the front sponson bars at an angle that seems as if air rushing over them would push the nose down towards the water, something that's going to need to happen with the balance so far back. do these plates actually do anything or are they just for looks?

any help would be greatly appreciated,

Joe

 

[Pitboy]

Joe,

Seal off your radio box lid however you are going to and submerge the hull, filling the various compartments full of water. Then release it and see if it still floats. Don't sweat it if the back is setting deep in the water as long as the boat floats.

The square plates you refer to sound like spoilers to help hold the front sponsons on the water. Try it with them, and if you don't like the way it handles, remove them and see what it does. Trial and error is the only way to know for sure.

Todd Zeller

 

[Grimracer]

Lax

The ride of the boat is very different then the sitting attitude. You can not learn anything about ride setting the boat in the water. It is nice however if the boats back does not sink as it is dead in the water because if you do not have your radio area taped well you it is going to get all wet. BAD

Now: What prop are you going to be running? You can start with an X prop if you like but the boat is not going to haul the freight until you get some lift in the back. I like the 1.6 by Octura or the 1740.

Grim

 

[_laxmasta2039]

P215 done by TunnelBill...Gene told me to get with you for a prop but im in the red right now and about to get redder joining the racing club so i'll have to wait till i can afford it.

I do realize it will be alot different once it gets on plane, but it's gonna be a pain launching it if setting it in the water means the back compartment sinking. The radio compartment is completely sealed as long as the hatch tape is waterproof. I put flotation in all the empty spaces but there werent very many of those..luckily the sponsons are foam-filled so i think it should stay afloat even full of water.

Joe

 

[Grimracer]

LAx

One note about hydros is that you have to give them a stout shove to get them on plane. Once there you are good to go.

Mike

 

[_laxmasta2039]

yea,

i've seen several vids of guys launching them and it looked like it would be pretty easy once you had practice [there's the trick ]

i have to say that one good thing about elec. riggers is you can just place them in the water and go....

im hoping to be able to run next weekend but i dont think it'll work out with the steering servo in the mail and all this snow on the ground...i'll try sinking it later and see how it does. :-X

Joe

 

[Grimracer]

LAX

Even with my e hydros i never just drop and go. I can get the boat on plane faster with a launch and use less power doing it. However your right in most cases the boat will still go.

Grim

 

[_laxmasta2039]

it's rained/sleeted/snowed/iced here for a whole week off and on.....great for the ponds and lakes in the long run but i still havent gotten the boat off the shelf [delayed gratification....hmmmm.....im gonna have to look that one up!! ]

not good for tuning this sucker but no-one else around can do much either- it's going to be one heck of a rusty first race here!!

Joe

 

[_laxmasta2039]

well,

the weather finally coooperated and i've got a brand new Hitec 645 MG steering servo, along with a good pond and weather- here's the result:

-arrived at the pond with matt and my bro an hour before sunset

-after filling the tanks and taping down the hatch, we hooked up the starter motor and flipped it on...the motor whined and ripped the jerry-rigged connector out of place!

-we decided to try wrapping a peice of tape around the flywheel 4 or so times, then pulling it off.....whadya know, the engine starts on the second try!!! i've got to send this tip in to RCBM.... : ;D

-after running the engine for 20 seconds, we cut it off and got everything ready to run....the engine wouldnt' start again. :-[

-after the sun went down and we packed up, i took off the plug to squirt in some after-run oil, and the plug was so loose it practically fell off!! :

we're going back tommorrow with the camera, hopefully the results will be better.

just wondering, does anyone else start thier OB's with tape? sounds crazy but it really does work.

Joe

 

[_laxmasta2039]

holy sh--!!

this thing can moooove!!

we started it up with tape and gave it a lil' push, the boat started screaming across the pond on half throttle/20% nitro with the nose 10" above the water and wobbling back and forth with every gust of wind....Grim would you recommend putting lead in the nose like in a tunnel?? the pond was a little too small and it went out of control, doing some "land-surfing" [aka hitting the bank : ] the flexshaft broke, the prop bent, and a rear sponson ripped off, luckily all can or have been repaired easily. got some pics, though none of it running. here they are.

Joe

 

[Rob Duck]

Is the engine completly stock? I used to run a 707 products slide exhaust throttle and the needle for the venturi. You remove the carb and insert the needle where the 2 screws were to hold the carb in. With this set-up you need to run crankcase pressure which is tapped through the side of the engine mounting lugs and into the engine crankcase. Hook this line up to the vent line on the tank. Run a 1740 3 blade prop and get ready to go 50+ mph on 50% fuel. If the engine is stock a 1740 2 blade will work or the 1.6 2 blade. my 2 cents....

 

[_laxmasta2039]

here's the whole thing at home afterwards...notice the paint stripping from the hatch tape.

 

[_laxmasta2039]

Rob,

it's got a pipe on it and may have head shims, so not stock....the carb's a regular ol' KB black plastic one, i'm looking to change to something better. here's a pic of the tuned pipe, the guy who sold it to me said it was an Irwin- irwin inboard maybe?? [notice the hole for an IB mount]

 

[Grimracer]

Lax

Land surfing.....!!! LMFAO...........

It is likely the prop needs to be changed to 1740 or 1.6 . Also put some neg trim in the motor..

You have a jewl for a pipe..its a Garcia and is the same pipe i used to win at the Internats last year..

Grim

 

[_laxmasta2039]

great!!

i was wondering why it didn't look like the other Irwins i've seen, i though maybe it was an IB. pleasant suprise though- if it's good enough to go on the internats-winning Villain, it's good enough for me! ;D

neg. trim sounds like a better idea than putting something heavy in ['cuz the added over=all weight] , but i remember JD saying [posting] once that he likes to use lead instead of neg. trim? is there any reason for this or is it just preference? i emailed the guy who i bought it from and asked him what kind of paint he used so i could try to get some and touch up the scrapes- Imron two-part. it's going to be hard to find in a small amount i think, also finding the right color might be a wee bit difficult if they've got alot.

Joe