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1/8 scale Hydro Hardware

Old 07-04-2005, 12:13 AM
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Default RE: 1/8 scale Hydro Hardware

Just out of curiosity, what is the prop weight? If you haven't checked this yet, balance the hull on the rear of the sponsons with the rudder sitting on a scale. You will want the boat to weigh less than 2 pounds at the prop. Having a light propweight lets the prop lift the rear of the hull easier, letting the engine unload quicker and ultimately giving better performance.
Old 11-26-2005, 12:14 AM
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Default RE: 1/8 scale Hydro Hardware

If you don't mind me asking , what radio box and fuel tank did you use. How is the cowl and boat going? i purchase a Atlas Vans Line used and working on rebuilding it, I have a long way to get it ready for the water.
Old 11-26-2005, 10:46 PM
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Default RE: 1/8 scale Hydro Hardware

You might have been sucking water into the carb by running without a cowl, but I'm just looking at possibilities. Are you running pipe presure to the fuel tanK? It might help too, if you're not. You might also want to downsize your prop again, to maybe around a 455. If you can, drop the pipe's height down as much as possible. A high pipe can make the boat act top-heavy in the turns. What is your prop weight? If it's over 1.75lbs, you're too heavy. The 10.25lb is actually very good for a 1/8th scale boat, so you have room to add some weight in the left sponson if you need to balance the boat for less prop weight. Just my .02
Old 12-14-2005, 12:58 AM
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Default RE: 1/8 scale Hydro Hardware

You've got waaayyyy too much prop on that thing. X457 3 blade is the way to go. The X457 2 blade will work as well but the 3 blade is smoother in the corners. I've run 50 different props and you can't go wrong with an X457 3 blade. It's a very good prop to start with. What fuel are you using, how much nitro, what head clearance, what kind of pipe and how long is it from the plug to the widest part of the pipe?

50% nitro is a good starting place. 9-12 thousands is the usual generic starting place. 9 thousands for 50%, 12 thousands for 60%. Use a cold plud, like #9 McCoys. Pipe length should be between 11 1/2 to 12 1/4. 11 3/4 usually will get you going. Typically if it runs for 100 feet and quits its too lean, but the props you were using will make that a difficult question. It shoudn't accelerate too quickly on the bench. When you blip the throttlew it should burble for a moment then clean out. It it is real zippy on the bench, it is probable too lean. Also look for dark smoke to come out the pipe. If you hold your finger in the exaust, it should get covered in oil quickly. White smoke and no oil on you finger - lean!

Be sure to check that water is flowing through the boat. People doing their first runs often forget to chech, and that will burn up a motor real quick. The head shouldn't been so hot you can't touch it for a second or so after running it. If you put a drop of dpit on it and it bounces off like it was on a hot skillett, it's too lean. It should sit on the head and sizzle slowly before evaporating away.
Old 01-02-2006, 09:32 PM
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Default RE: 1/8 scale Hydro Hardware

Hello too all, forgive my absence of not answering as I see it has been continued with questions. I thought boating season was over.....

@ DMACK - These are the Props I have on hand at this time, X447 - 3 blade, x447 - 2 blade, X448 - 2 blade, Prather 240 - 2 blade and the X462 - "DID not Work" I will purchase the X457 2 and 3 blades to add to the collection.
The fuel I am using is the Coolpower 25% nitro, I know I can go Higher but the engine I am using is a no go on the Con -Rod, If it breaks, The engine is Buy Buy. So I want to baby it a little until I get the MAC .67 or new OPS .67
I have the pipe set to 11" per Andy Browns spec's / recommendation but i have another inch of adjustment on the header. You are right on the too Lean, I was tuning to lean on the beach before launch, I should have known better as I raced cats and tunnels. I bench ran it with a water pickup and pump system to continue water flow through the engine and it stayed nice and cold to the touch. I Do Not like the rudder pickup system as I am used to the pickup from the prop on my outboards and can see it immediatley upon entry in the lake.

@ Hydro Junkie - Yes on the pipe pressure to the tank, I have the fuel pressure tapped at midpoint / wide on the pipe. Definatley could have been water in the carb as it was a little rough that day. I am putting a metal spray shield in front of the carb for that purpose in the future. I have about a 1" gap to adjust pipe down in the back due to my electronics placing. The pipe hits the box. I measured the boat again and it is still 10.25 lbs which you say is good. I did what you suggested and got the prop weight, mind you I used a house scale but it came out around 3 lbs. So it looks like I am too heavy in the rear and need to compensate by adding some forwar / left weight to compensate.

@ Talon 25 - I used the design of the radio box that they incorporate on the plans. But as you have read in threads. It might be a good Idea to put the electronics forward of the engine and change the placement of the fuel tank. It seems I came out heavy in the rear and this would make a big difference, might take it into consideration and I am sure the guys hear will let you know as they have been a great help in my endeavor thus far.

I am going to get this beast running this summer and it WILL be a blur if it the last thing I do!

Thanks all
Updates will come as usual, but I am in Helicopter and plane mode now
Old 01-02-2006, 09:42 PM
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Default RE: 1/8 scale Hydro Hardware

Oops - forgot to answer one other from Talon - It has a Dubro S-14 ounce tank. I have seen the low profile tanks in other applications and might go the route when I rebuild my dads Dumas Drag 'n Fly 60. Put the tanks under the decks and put electronics in the front.

Jeff

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