ryan_t888

I never really had an ESC glitch. That's strange.

I believe the ESC does not have thermal protection but I am unsure on this one. If it did have it, the temperature in which it would kick in is higher than 145F

To be honest, I wouldn't worry about your temps as they are in check. If you leave that prop on you will have a quite reliable hull. The only thing I would do is cut your run times a little bit shorter. Try to pull a Max of 75% capacity out of the pacls. For you that would be approx. 3800mAh. This will also extend the life of your LiPo's and in addition, reduce some of the heat build up.

Ryan

diabolic-mind

sv27, that boat is just awesome, for something you built you must be completely thrilled with it and its performance. very nice work. are you going to keep the wood finish look are give it some color? personally i think it would look amazing with some type of animal painted on it with the wood finish

SV27dayton

Thanks Ryan. I can't remember what you said is the scary temperature, but I'll look back and find it. I'll cut the run times back. I'm just now getting to where I routinely get a whole run out of it without flipping or haveing a minor driveline issue so I'm only now seeing the heat soak. The packs are pretty warm as well so your advise is sound.....again[:-] I may play with some between run cooling with a pump for kicks, I can also back the timing down a bit more although it's pretty conservative now. I need to get a good video so you guys can really see how it behaves. You can see there was almost no wind but going right to left it would lift and I would have to back off. It's really running loose with any amount of head wind. Going the other way I can go full tilt and the steps stay on the water. It prop walks through the turns right turns a bit (which looks soooo cool but if i slide over some parallel rollers it will barrel roll, but it turns well at speed and ridiculusly sharp at slow speeds. I am pleased with it DM. As for the looks I have a side business cutting vinyl so I'm planning on putting a multi color stripe pattern on it to wake it up a little but I want the wood grain to be visible. I want there to be no doubt that it's hand built. Needs a new canopy first though and I'm having too much fun running it to work on it.

ryan_t888

I don't like to exceed 140F. Although regardless of what I do, I could not get my SV27 motor to stay under 145F. Even with an X440/2, so I just let it be. Neu motors seem much better in the heat department. A lot more predictable.

If you hang around the car forum you will see a lot of the guys run their motors a lot hotter than we do. So in other words we do have some wiggle room. 140F is just a safe goal. I don't see a reason to exceed this number with very few exceptions.

Ryan

SV27dayton

My buddy Randall finally made it over to the pond and got a good video of the cat running pretty well. It was a little breezy so the packs are way forward and I didn't have my "inverted extraction gear" with me so I was pretty conservative approaching my own rollers. I'll edit and post some great still shots tonight.

http://www.youtube.com/watch?v=hbkDe8Io5S8

diabolic-mind

that thing sounds so sweet as it cruises by. i like it so much im considering building one on a micro scale. only difference would be im using the electronics from a suhkoi micro aircraft. but im confident i can use the electronics and make it work. the tough part is going to be scaling it down to about 7 or 8 inches long. thanks for the inspiration sv27, when i finish the build ill be sure to post some pics of it in here for you

SV27dayton

That would be the best compliment you could give me.

verado

Very nice build!!!
I just about skimmed through every page. Couldnt seem to find where you ordered the Balsa and what thickness you used?

SV27dayton

I bought it piecemeal at the local hobby shop. All the structural stuff is 1/8. I beleive the skin is 1/16 and then I CA glued a skin of 3 ply 1/64 birch over it. Then I glazed it with polyurathane.

SV27dayton

Some of the promised photos from earlier today......

SV27dayton

More........

norbique

Very nice running boat! Thanks for the video and the pictures too!

diabolic-mind

in some of the pics it looks as if it isnt touching the water. im thinking on the micro build version im doing im going to use foam to keep the weight ultra light. sz27 can you tell me the purpose of the angled cuts on the bottom? im not too familiar with boats, there still new to me, thanks

SV27dayton

DM,
Those are the pictures that I posted because they are the coolest! Actually the hull is on the water more than the photos suggest. The angled cuts are why it's called a stepped cat. They are forward angled cuts that are designed to interupt the water flow under the hull and inject air under the hull/break the wetted surface to decrease resistance. I've seen the same hull done with out them but I don't know how they run. To your point when the boat is in the air they are not really functioning (they've done their job by then). The true 1:1 boats probably get more from them than their RC counterparts because their scale speeds are significantly slower and consequently their hulls wetted more often but you see steps on many RC race boats so I'm sure they add value. You can see better views of them in the following posts in this thread 48 52 58 77 102 117 227 247

Also here's a link to some videos of the Callen boat that insipired this build.
http://www.rcuniverse.com/forum/m_2566613/printable.htm

hope that helps.

diabolic-mind

nice, thats for the info, seeing as how the boat im building wont be fast i might leave the steps out. but a micro version of your boat is gonna be so cute :P lol

SV27dayton

Anyone have a recomendation for the best water for a top speed run for a catamaran? I ran the other night at the largest local pond around and it was so breezy that I could only run in one direction w/o blowing over, but I think with the chop and the tail wind I was probaby at my personal speed max. I'd like ot best my old number so I have it when people ask. (they always ask)

ryan_t888

I'd say at this scale, low wind/glass water.

Ryan

SV27dayton

hmm I think I'll have to verify that>

SV27dayton

Ran both pack sets really hard today. Slight ripple on the water, running on a sailboat course working on turning at speed. I need more work. She slides in the turns. I'd hate to put turn fins on but I wonder what they would do. Looks pretty cool but I don't know how much control I really have. Anyway I'm charging the second set of packs back up now. First set took 4400 of 5000. Both packs sets were hot (140s when they came out of the boat). They were a little puffy. All 4 about the same. Puffiness went as they cooled down. I've read that this is probably OK but it's the first I've experienced it. I'm using zippy 40C 5000 2x2S.

SV27dayton

Update: Went out and ran at lunch today. The plan was to get new GPS numbers as I think I'm faster than with the previous prop. Walk your shoreline kids. After about 6 good passes I hit a submerged log. It was only sticking out about 1/2 inch but it apparently went all the way to the bottom (the log) not the boat. It ripped a chanel down the port side of the tunnel and sprung the transom pretty significantly -steering servo is loose, and some of the top skin even came up. The stinger is mangled. It's repairable- and actually could have been much worse, but it will never be the same. I think I'm going to have to put it away for a while. I'll post some photos sometime later. Time for a good cry.[]. GPS'ed at 47.7.

08gtrking

So sorry to hear that hope bests

ryan_t888

That sucks man, I'm sure you will have her repaired in time. But your gps number is excellent. Congrats on that.

Ryan

SV27dayton

View the carinage. I have my work cut out for me. Note the dark wood at the front (not original equipment)

08gtrking

I can`t look. so the log hit the tunnel lucky it did`t hit the stinger it could have been worse

ryan_t888

08g, I think it was you who pm'd me about hull material.

This is one of the main reasons I build with PLY only. Balsa is too light and very weak. I strongly believe my ply hull will hold up far better than balsa hulls or ply/balsa combination hulls. Only disadvantage is increased weight, but then I just budget in more power.

Hull strength is important when achieving high speed numbers. I've seen ripped apart balsa hulls just from a blow over. Not fun to constantly repair these after every incident.

Scott,
Looks rough. At those speeds, lots of damage can occur very quickly. Are the parts that were ripped up built from ply?

Ryan