My New Mini Eco! Set up tips?

[Rich]

I just received my Mini Eco from Jim over at Minicatracing with my OSE membership discount. The boat came nicely packed with motor and servo installed. The esc came in a plastic bag with decals, instructions for the esc and boat, and a programing card. Once I was done with soldering the deans on the battery leads, I programed the esc for 3s lipo and used low timing and pwm. Programming the throttle range using my DX3S was a pain!! I had to play with the brake travel in order for the esc to recognize the neutral position. Once all was figured out I put a 3s lipo in a headed out. I had the lipo sitting in the middle of the boat up against the flood chamber wall. It was windy out and the boat handled the wake well. It did not self right and I stuffed it many many times; it came back up. :thumbup1:

I have made a few adjustments:

1. Added a pine car lead weight to the back of the flood chamber.
2. I flipped the servo arm around so I could move the lipo back against the transom (see attached pic)
3. Added some pool noodle foam for added assurance.

The boat handles much better now and it self rights. Sometimes I have to give the throttle a quick kick for it to flip over (which can be fixed with the addition of weight and a vent hole or two on the deck).

The other problem I am having is the boat still stuffs, but only in right turns. The boat spins out on left turns. Is there anybody that can give me a few tips to remedy this? In a straight line the boat seems to be good, but I hear the prop coming out of the water a lot. Any ideas?

[martin]

Its pretty much standard to add weights on these for self righting, Most use the stick on balance weights which come in 5 & 10 grams & stick them as far to the outer edge as possible. Some put them inside the chamber & some stick them on top of the deck & place them if nessesary spread along the hull for better cg balance rather than just putting them all at the rear of the chamber. You def want to add a few holes along the chamber for water to flow in faster & air to get out. When i spoke to Tenshock about cg position they say 190mm from transom centre which is 44%, I found 175mm or 41% works much better & reduces diving but not completelly. The diving is also caused by the angled shaft with sub surface props, When you put the boat into a turn the boat banks over & the prop breaks the surface. You can hear this from the prop when it does this & the angled shaft drive line is pushing the back of the hull up & the front down & the front side thats dipping down catches the water & causes a dive. This isnt all the time as the boat turns very well in a very sharpe turn but its worse when the boats going faster in a straight line & you take a wider turn. Martin.

[martin]

One of the mods they do here in Europe on Mini Eco class boats when racing is the replace the entire propshaft assembly & replace it with something like the Etti wire drive Eco shaft assembly where the outer stuffing tube has a very gentle curve with a 1.2mm wire drive. So the prop drive angle is only 1 degree, It produces a faster more stable boat because the trust line is pushing the boat fowards & not upwards & foward as the standard drive has. You also get better handling in corners as the prop drive line isnt pushing the back up & front down. They also lower this shaft a bit to get bigger props on as stock 27mm props are very close to the hull & you cant put bigger diam props on. You also have to use a bigger rudder blade (30% bigger) on this setup to handle turning at higher speeds. It just depends on how fast you want to go re mods. Martin.

[martin]

One of the mods they do here in Europe on Mini Eco class boats when racing is the replace the entire propshaft assembly & replace it with something like the Etti wire drive Eco shaft assembly where the outer stuffing tube has a very gentle curve with a 1.2mm wire drive. So the prop drive angle is only 1 degree, It produces a faster more stable boat because the trust line is pushing the boat fowards & not upwards & foward as the standard drive has. You also get better handling in corners as the prop drive line isnt pushing the back up & front down. They also lower this shaft a bit to get bigger props on as stock 27mm props are very close to the hull & you cant put bigger diam props on. You also have to use a bigger rudder blade (30% bigger) on this setup to handle turning at higher speeds. It just depends on how fast you want to go re mods. Martin.

[Rich]

Its pretty much standard to add weights on these for self righting, Most use the stick on balance weights which come in 5 & 10 grams & stick them as far to the outer edge as possible. Some put them inside the chamber & some stick them on top of the deck & place them if nessesary spread along the hull for better cg balance rather than just putting them all at the rear of the chamber. You def want to add a few holes along the chamber for water to flow in faster & air to get out. When i spoke to Tenshock about cg position they say 190mm from transom centre which is 44%, I found 175mm or 41% works much better & reduces diving but not completelly. The diving is also caused by the angled shaft with sub surface props, When you put the boat into a turn the boat banks over & the prop breaks the surface. You can hear this from the prop when it does this & the angled shaft drive line is pushing the back of the hull up & the front down & the front side thats dipping down catches the water & causes a dive. This isnt all the time as the boat turns very well in a very sharpe turn but its worse when the boats going faster in a straight line & you take a wider turn. Martin.

Thanks for the info Martin. I took it for a spin just a little bit ago. I placed the battery a little more forward. My cg is at about 160mm from the very back edge of the hull were the seam for the two halves are. Is that the right place to measure from? I noticed that the hull likes to be a tad flighty. I also noticed that left turns the boat has never stuffed. The hull likes to hop in left turns until it gets a "grip" on the water. I am also getting this random change of direction when driving, its like the servo is glitching. Any thoughts?

[martin]

Yes cg is measured from the double seam in the centre of the hull, So furthest point back on the hull. I ran many points ranging 190mm as suggested by Tenshock down to around 155mm. I found 155-160mm to be to far back with the front riding much to high, The best position i found for the conditions i was running that time was 175mm. I think what you have to consider also that these hulls were not initialy designed for use with lipos or the extra speeds that are possible over the old ni cads or ni met hyd batteries. Martin.

[martin]

Boats never turn as well left as they do right because of the torque direction of the prop. This is why boats have most of their batteries etc to keep a bias to the left of the boat to help in turns & also to aid self righting with the flood chamber on the left as well. Most race boats are only intended to turn one way fast only using 1 turn fin set to the right of the transom to turn right. Turn fins are not used on mini eco class boats though.Martin.

[CaptPJB]

:sold:Interesting info on the Eco
Always wondered why most videos show them running anti clockwise or left while most other boats go right must have something to do with the stuffing problem going right mentioned here

[martin]

Yes the boat does dive more in fast right turns than left as the front dips in a right turn & catches the right front. I dont think it has dived much if at all in left turns. Martin.

[sailr]

It sounds like your battery is still too far back. Move it forward in 1/4" increments until you find the sweet spot! Look at the balance point on our instructions that came with the boat.

[Rich]

It sounds like your battery is still too far back. Move it forward in 1/4" increments until you find the sweet spot! Look at the balance point on our instructions that came with the boat.

I'll give that a try Sailr. How to you guys check the balance point? I mean do you just hold it with two fingers and see where she sits?

[sailr]

Yep, a finger from each hand inside the lip of the hull with the hatch off.

[SweetAccord]

It's easy to understand that a CG towards the front tends to maintain the bow down into water, increasing the wet area and hampering the planning of the boat when at speed. On the other side, a CG too close to the transom tends to raise the bow too much, making the boat unstable at speed. As a rule of thumb, CG must be between 27% and 30% of the total length of the boat, measured from transom, for a completely assembled boat - ready to run.

Everyone will try to tell you that it should be about 30% of the hull from the transom but not tell you how to figure that out. Here's how: Measure the hulls length. Multiply the hulls length by .03 and measure this point forward from the transom and mark that point on the hull. Check the hulls actual balance point with (finger method) and move the batteries for or aft to make the hull balance on that point marked. Run it and if the bow rides low and plows, move the balance point back an inch from the balance point that was marked. If the bow hops, move the batteries forward an inch.

[martin]

The 30% ish cg does not apply to these Mini Eco sub surface drive boats, I know this from extensive testing of this boat. 30% = 127mm, This is immposible to acheive moving everything right to the rear inc turning servo, rx right at the rear, battery touching transome, esc further back,stick on balance weights at rear of flood chamber. The furtest back i could get the cg was around 155mm = 36%, The boat handled terrible with the front way to high. I also spoke with Tenshock in China & asked them on cg & they said gc is 190mm which is 44%, I ran 190mm & found this to far foward & got to much diving & tried several points between 165mm & 190mm & found that 175mm = 41% worked best & reduced diving.I dont know weather its coincidence but theirs a Tenshock sticker inside the hull bottom that also has a mark on the centre of the oval sticker that is 190mm from the rear possibly an indication this is the cg point. This also looks the same area that Minicat show on their cg point details. But im sure Sailr can say more about that area that they show as theirs no measurment given on the site. Perhaps you get a measurment with the boat instrutions i dont know. But like i said the general rule of 30% + / - that we normally apply dosnt seem to work on the Eco class boats. Martin.

[sailr]

With all mini boats, the CG can be somewhat subjective. Move the battery fore and aft til you find the sweet spot and then mark it! Remember, weights of battery packs vary from brand to brand so the best spot for a 3S 2100 Hyperion may be different than with a 3S 2100 Turnigy. Also note that the higher the "C" rating of the pack, the heavier it will be.

[Rich]

Thanks for the tips guys. I just drove it a bit ago. I moved the battery up so the back of it was equal with the center of the servo horn screw. It handled very well in a straight line. Left turns it likes to hop still. I think I need to get a new lipo with a higher C rating. The lvc kicked in about a min of running. I will have to see with a better battery what this thing can really do!

[sailr]

Is she running cool? If it's getting hot, it would cause the temp cutoff to kick in. BE sure to check that as well. Another tip for the battery, I mount mine against the flood chamber wall, on it's edge. I put velcro on the wide part of the battery and also on the bottom edge. That way it holds the battery against the bulkhead AND the bottom of the boat. That concentrates more weight on the left side. The hopping in a left turn is probably because of torque. You need more weight on the left to counteract the torque roll, so it can't lift the left side of the boat.

[Rich]

Thanks for the tip! I just ran it again with the back of the battery just behind the servo horn. It ran really good, no stuffing in right turns and it hops less in left turns. I have to add some weight to the left bc it doesn't self right. I figure this will solve the hopping problem too. The temps were 95f on the motor 85f on the esc. I did notice more water coming out of the cooling system more often than not. I might end up lengthening the pickup tube just a bit to aid in cooling. I most def need a different lipo, the temp was at 137f! I know they can get that hot but with a new battery it would solve the heat issue and the weight issue on the left side. Of course this means I am going to get a slightly heavier battery :biggrin:

[sailr]

Temps are perfect. No need to mess with the water pickup tube! The lipo is a bit warm to be sure. Use a 3000mAh pack if you can fit it in there. That way you won't need to add as much weight to the flood chamber side.

In addition to adding weight to the left side, cut some bigger holes in the deck. This allows the chamber to flood more quickly and thus self right more quickly.

[Rich]

How about this pack? Will it fit? http://www.hobbypartz.com/77p-sl3000-3s1p-30c-3333.html

[sailr]

I'm not sure. You have the boat there, measure the area where the battery needs to go. The dimensions for the battery are at your link.

[Rich]

I think the width might be a tad too long. It may hit the cowl. What lipo do you use?

[martin]

The tallest you can get right over against the flood chamber wall & under the hatch lip is 37mm, slightly less if your moving the battery further back past the servo. I use a 34mm wide lipo & it just goes under the lip. Martin.

[Rich]

I order the Skylipo 3000 mah. I should be able to fit it in if I lay it down.

[martin]

I order the Skylipo 3000 mah. I should be able to fit it in if I lay it down.
If you have to lay it down which i suspect you will have to + its a much heavier battery then you will have to add more weight still on the chamber side of the boat to get self righting as your moving weight towards the other side with it layed down. Martin.

[Rich]

If you have to lay it down which i suspect you will have to + its a much heavier battery then you will have to add more weight still on the chamber side of the boat to get self righting as your moving weight towards the other side with it layed down. Martin.

That's what I figured would happen. I'm not too worried about adding more weight to the hull since I do run in somewhat choppy water.

[Rich]

I final got to run the eco with the 3s 3000 mah sky lipo. I have to say the extra weight really helped the handling! It doesn't hop as much in left turns nor does it dive much in right turns. I still need to add weight to get it to self right. This thing really hauls A$$!!! Now if only I could get my Gecko to run like this. I'll keep you all posted.

[sailr]

Did you ever enlarge the holes in the flood chamber? You may have enough weight on the left now but the flood chamber needs to be able to "flood" quickly for proper self righting. Can you post a pic of your boat?

[Rich]

No I haven't. I have one hole in the top and thats it. How do you guys cut holes in yours? With a knife or a drill bit. I can post pics later.

[martin]

Be carefull when drilling as you can split the deck quite easy as the glass is very thin, Also watch the drill dosnt bite as it can pull the drill & go through the bottom of the hull as well especialy if your putting larger holes in. Martin.

[sailr]

I use a cutting wheel on a dremel tool and then the little drum sander on the dremel. You can take small bites at a time and end up with a very smooth cut. The guys in Europe cut some crazy shapes into the decks of their flood chamber boats like club, spade, heart, and diamond and stuff like that. I'm not that good with a dremel to do that!

The hull is very thin. Be careful

[Rich]

How many holes should I put on the deck? Should I put them all the way back to the trans?

[martin]

Ive found you dont need to put holes all the way to the rear, When the boats upside down it sinks down one side as water enters the rear of the chamber so can trap air that towards the front. Having holes starting from around the motor area & going back say 5", I have 4 .25" holes spread 1.5" apart & it floods & rights very quickly. The more you put or the bigger they are more water will get in quicker but ive found theirs no point in putting to many unnessary holes when you can get it righting very quickly. Start off smaller & simply open them up if you find it dosnt right as fast as you would like. Martin.

[sailr]

The holes in the deck are to let the air out! Martin's advice is perfect!

[NativePaul]

I did mine with a mixture of the dremmel and a scalpel, just the scalpel would have resulted in a neater job but taken MUCH longer, Martin is right about the thin deck in the flood chamber some of my fancywork is too fancy and too weak, I broke part of the 2cell battery symbol off while cutting it out and broke a part of the earth symbol off when rubbing down for paint, the warning high voltage and danger shock hazard symbols are pretty weak too and though I haven't broken them yet if I was doing them again I would leave bigger bridges in the corners. The high voltage lightning bolt,ohm symbol, 8.4, resistor symbol and brushless motor symbol are all plenty strong enough, which should give you some idea of what you can get away with if you want something fancy.
http://i22.photobucket.com/albums/b310/nativepaul/tenshockminieco003.jpg
Sailr, it is my belief that the holes in the deck are to let the water in, not the air out. By some strange coincidence mine always seems to be upside down when I want it to self right!:sarcasm1:

[sailr]

The original holes that come with the boat, a couple of small holes, are to let the air out. The water will come in the back of the flood chamber but unless the air can exit the chamber, the water can't flow in. The faster the air can exit, the faster the water can flow in. With you're extensive cutouts, I'm sure they facilitate both water and air.

Your boat is super cool!

[Rich]

I drilled more holes in the side and took her out for a spin today. It didn't self right, but i need to put some more weight in the chamber. The motor stopped and the controls went dead. Turns out there was water in the hull?:huh: I dried everything out and ran it once again. It did the same thing and again I found water in the hull. :huh: Which would explain why it self righted multiple times. I left the hatch off and placed it in the water with nothing in it. I came to find out my dumb self must have nicked the flood chamber wall with the drill bit causing a small hole right next to the motor. :doh::doh::doh: I am now waiting for it to dry so I can plug the hole with epoxy. ...:cursing: Tomorrow is another day.

[Rich]

Well I got her all glued up and added some weight to the left side and bingo! It self rights with no leaks! :banana: I would like to thank Sailr for the discount and the advice. Thank you all!

[sailr]

Good to hear Rich! Thanks for the kind words. My main goal is to be sure everybody has fun with our boats!

[Rich]

Your welcome! I am looking to get a Starship later on down the road that would be a fun boat. I drove it again and had a mishap, it was a bit choppy today. It handled it well until it dove and didn't come back up....:cursing:I had my fishing rod with me and started casting for about 45 min. My brother got some chain to see if we could stir it up since our lake is muddy. We also enlisted the help of a boater that was passing by to use his motor to stir it up, but with no success. I knew it couldn't have sunk. My gecko was submerged for 45min until I pulled it off the bottom and it popped up and drove it back to shore. I left to get some heavy duty line and hooks to snag it. My brother called me when I was on my way home about 1 mile from my house and told me it came up!!! :w00t::bounce::banana: The best part was that there wasn't more than a few drops of water in the hull!!!:rockon2: How the heck the Eco and the Gecko dive down 3ft and get stuck in the mud is beyond me! I think I need to design a float system that activates when the signal is lost via the 3rd channel and looks good......any ideas? I am thinking about something that can release a bobber with enough line that it can reach the surface so I know where it is.

[NorCalZ71]

the float idea would be fairly easy. just mount a traxxas waterproof micro servo in the flood chamber and make a catch pin to hold the bobber in.

[Rich]

Thats not a bad idea NorCalZ71, I'll have to look into it for my Gecko too.

[stevie]

Hey guys I'm new to boats im 20 I've always raced 1/18 brushless on road and I'm sponsored through max amps batteries. My dad had a prather spitfire 2 nitro with a k&b7.5 modified out in california years ago. I've always loved rc boats and I got my dad back into it. Then when I found minicat I couldnt beleive how much better then all the other micros. I kept reading and doing homework on them. I finally decided the eco was amazing. I ordered one from them on thursday and got it on monday ive worked on it all day and I think im gonna see how it handles tommorrow. I live in michigan and the pond were they race their nitro hydros and mono's. Hopefully my dads boat will run by then but im looking forward to blowing them out of the water. Is there any advice or tips you would share. I have 2 cells and 3 cells and the 3200 kv should I just run the 2s. I cant wait to run this boat please help if u want.

Thanks

Stephen

[sailr]

Thanks for the kind words! You can run the boat on 3S OK. That is 35K no load rpm. No worries.

[stevie]

Ok cool thanks I just got back from running it and its on rails im having trouble getting full rpms out of it though. Ive tried reprogramming the throttle response but it wont get up to plane if I adjust the throttle trim so it goes about ten mph when my throttles at nuetral itll go a lot faster but still not close to full speed. If I set the esc to auto will that work for both 2 and 3 cells. Im looking to make this boat to be a serious racer.
Thanks sailr
I would like to talk to you personally about this boat I have a few questions. Can't wait to get this boat screaming

[electric007]

Programming the throttle range using my DX3S was a pain!! I had to play with the brake travel in order for the esc to recognize the neutral position. wow!!!!!!!!!!!
im still cant get mine to work correctly>>

[stevie]

Im gonna run it with a 4 cell tommorrow but does anybody know what prop I should use

[sailr]

Seems a lot of people have trouble with the Spektrum radios programming with various esc's. We can't help you if you're using Spektrum.

[sailr]

Good luck with that. You run the chance of blowing the esc and motor on 4S. That will produce 46,080 no load RPM! Too high for the motor. It will NOT be warrantied. You definitely will need a smaller than stock prop on 4S but we don't carry any because the boat is not designed to run on 4S.


Im gonna run it with a 4 cell tommorrow but does anybody know what prop I should use

[stevie]

Ok thank you I havnt yet and im not going to now were going to the pond in an hour what batteries should I be using all my packs are between 800 and 1200 mah 3 cell and they dont power the boat it will only have power for about 5 seconds then slower than 2 cell I need new lipos what should I get

[NativePaul]

Use your 1200mAh 3s pack it should net you a little under 4 minutes of runtime, if your in the states I doubt you will be racing it, but the Naviga rules for mini ECO give you a sub 110gram 2-3s LiPo pack which is about 1500mAh in 3s, with which to do a 6 minute race plus in lap.