Zelos 36 - First Day Out (again)

[mikiek]

After a week of pulling my hair out trying to fix my throttle issue, I got some quality time with the z-boat today. Good fun but I can see I need to make some adjustments. I was running with all stock parts today, wind was 5-10 mph, water had just slight ripples not too bad.

First run was with a 6S Lipo on each side. Placed as far forward as the hatch edge would allow. She ran well but it was obvious I needed more weight. I flipped her almost right off the bat. After that, watching close, I could see she was bouncing across the ripples and looked like she needed more weight.

Next, I put in 2 3S Lipos on each side. Again, as far forward as they would go - 3S will slide under the deck. A slight improvement on the bouncing but still could not open up the throttle all the way. I was probably at 3/4 on the trigger - there plenty left that I was scared to use. Down wind I did get up to 59 mph if you can believe the GPS.

So, I have about all the weight I can add with the 4 batteries. Would a strut adjustment be next? Slightly downward to hold the front end down?

[Fluid]

Where is the CG relative to the back of the sponsons? With the boat resting on a flat table, are the struts parallel to the table? If not, make them so. If they are, angling them down slightly may help depending on the location of the CG. What props are you using?


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[Erroneous]

Both struts need to be set at EXACTLY the same height. I agree with the negative angle (pointed down) of the struts. On both my Z36 hulls 3-4mm negative angle from bottomed out is the sweet spot. The manual shows how to adjust the struts. I bottomed mine all the way out (run it) and started raising them (run it again) using my allen wrenches as gauges. Id start with the batteries forward then as it smooths out with the struts start sliding them back. My first hull was so good at holding a beat on the water this is all that worked.

[Erroneous]

Be carefull with the struts angled down until you raise them to air the boat out. Electronics will run hotter the wetter the hull is riding. Run short runs.

[mikiek]

Hey Fluid - with the 4 batteries CG is roughly 12" from back edge of sponson. Struts are parallel to bottom line of sponsons - I extended with a ruler. Props are stock that came with the boat. Manual says 1.4x1.65

[mikiek]

I can ask this since I'm still a newb - I know angling the struts down will get the bow into the water more. Doesn't that also raise the stern? If yes, is this really my solution? Watching the boat today, the whole thing was coming out of the water, not just the bow. You could hear the engines scream everytime the props came out of the water. It seems like I need more weight distributed all along the bottom of the hull.

A related question. When the boat gets up to speed, I imagine you get some serious airflow between the sponsons. If the bow is riding slightly higher than the stern, it seems like you would experience the stern trying to lift up since the opening at the bow would be larger than the opening at the stern. You're forcing more air into a smaller area. I suppose the opposite would be true if the stern is riding any higher than the bow. Does any of this come into play or am I thinking too much?

[Erroneous]

I know im not Jay but yes it all plays a part. Try what I suggested or dont.

[mikiek]

Erroneous - I will definitely try what you suggested. It will be interesting to see what happens.

[REDLINE1]

Check out this thread

https://forums.offshoreelectrics.com/showthread.php?55630-Strut-adjusting-jig-for-my-

I made this so I could get my struts adjusted even. Much easier than the rulers Started at the stock 4mm with 2 3S batteries then lowered to 3mm. Now this season w 4 batteries (inline) and 447 props I did cartwheel it so next time out I'm gonna try 2mm. Also notice I get more bow hopping when the water is glass then if there's a little chop. Doesn't make much sense to me but I'm still learning

[REDLINE1]

Also check this link out posted by one of the members on here. Good general setup info for boats

http://zenoahmodifiedengines.com/rc-boat-tuning-tips.php

If you scroll down there's a section on cats for hull balance

[mikiek]

REDLINE - I like your jig for getting a consistent adjustment on both sides. How do you make say a 2mm adjustment? Also like your PVC stand.

I was surprised today at the amount of bouncing given the relative smoothness of the water. Of course I was running faster than I ever have :unsure:

[REDLINE1]

I adjust the screw on the tip of the gauge to whatever setting I want. I use a dial caliper to set the distance the screw protrudes from the bottom edge of the gauge ,say 2 mm Then lay it in the bottom of the boat like in the picture to set the strut. I did shorten the gauge to cover only the two rear ride pads

[mikiek]

Didn't get out today, still catching up on things I missed while working on the throttle problem. I suspect adjusting the struts and testing them will take some time so it may be next weekend. I did see something in the setup post that REDLINE suggested. From that page " If the water is calm, increase the angle to lift the nose higher out of the water, which will decrease the drag of the hull, resulting in more stability and better performance." Does this sound right? For calm water I could see having the struts level (0 angle) but angling up?

[vinnyp]

Not the expert here... but angling the struts up will increase bow lift. Decreasing drag by allowing the hull to ride higher out of the water = more speed. The trick is to get the bow to lift enough for max speed but not too much where it blows over. Its all trial and error. As you said, the wind and water conditions will play a big role on set up.
Here in New York, the wind has been howling just about everyday. Between the weather and being slammed at work, I have not been able to test mine for a long time.

[mikiek]

I know what you mean about the wind - it's really blowing here too. Fortunately, the place I have been putting in is somewhat protected.

I'm still wondering if strut adjustment is the problem. My last run, the boat was like a rock skipping across the water. I may be all wrong but it seemed like it was just too lite. Yes, we want the hull up, but I think we want the props in the water too.

I've got a lot of experimentation ahead. Finding a good CG. Seeing what the boat does with various strut angles. And of course all that changes between calm water and rough.