"Orange Cat" build 2013 - Fast and Reliable

[cugino]

Hello,

for next season 2013 i am going to build my new boat. It is 930mm long custom build carbon/kevlar catamaran hull. I wasnt sure about the suitable hull lenght, beacuse my intention was fast setup, but i didnt want to ruin my wallet much :-) I Thing that under 1 meter long hull will be enough for good speed, reliable setup and low budget boat. We will see.

I am not boat racer. I only want fast boat for holiday bashing. I will build twin motor powered boat, just becasue i like the roostertail and handling of twins. Nothing more.

There is my custom made hull. It is carbon aramid hull. Bottom part of the hull is carbon/aramid, hatch and top part of the hull is aramid only. Resin is high strenght epoxy with aerospace certification. Hull is tempered, unfortunately not vacued. Next time i will be smarter.

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I am not sure about HW i will use. I am only sure i will use wiredrive. It si simple, cheap, reacheble, reliable and efficient.

I am not sure, what motor, ESC (most likely T180) or battery i will use. I want to run only 6S configuration batteries, because all other boats i have i use 6S. I would love to try 6S A-Spec Nanotech 6600mAh 65-130C in 3S+3S configuration. Each pack in sponson. I prefer very light setup, all the build will be build within this phylosophy. All components will be as light as possible. Just try to look on 6600 Aspac nanotech - power/weight/capacity ratio.

[cugino]

I like doing as much as i can myself. Buying thinks is realy simple, but with no satisfaction for me. And finaly i want to save as much money i can to have low budget boat. I have some time these days, so i can play :-)

Today I will prepare servo mount. I will use low profile china servo, because it is only one that fits this low hull quite well.

There is my servo mount: I like to prepare all my carbon part first. Then assembly part togather. I always build boats like that. I will start with smallest parts then assambling together. Finaly equip hull with prefabricated components.


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[cugino]

Hi folks,

Its time to move on. I ordered some HW. I think, it fits very well. Some modification were done outside the hull. Here are some pics.

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I think, choosen HW is light and stiff enough for the hull this size and power. Stingers are shorter metric version (4mm). 4mm version offers me variable use of different props, either bored 3/16 or 4mm.

I prefer high revving setups, so everythink is done to handle high rpms well. But about driveline i will write more in future.

Next time, there is need to make some progress inside the hull.

[cugino]

My build continues. Today i did some work inside hull. I started with receiver battery holder. I dont trust china BECs, either internal or external. I was considering NiMH batteries, mostly Eneloop. But i dont have good experience with NiMHs at all. But i have nothing to complain on A123 LiFe batteries. They are pretty suiteable for receiver. The voltage is very similar to 5cell NiMH, so there is no need for BEC at all.

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[cugino]

Today i could install stuffing tube. I picked up carbon tube 6/4mm. It perfectly fits in my stingers. With wiredrive it is perferct stuffing tube. I glued carbon tube leveled with bottom of hull then will bend to correct radius.


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I also prepared some carbon and metal garbage. I made inlets and outlets from brass tube. I was warried about silicon tube sliding off, so i solder welt from copper wire. I think i will work perfectly.

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[cugino]

Epoxy is drying, there is time to prepare some other suffs.

My servo links:

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[cugino]

Motor mount. It si made from 2x 1,5mm carbon sheets. Glued togather and then filed to proper shape. That was terrible and took lot of time.

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[mtbenjamin77]

Motor mount. It si made from 2x 1,5mm carbon sheets. Glued togather and then filed to proper shape. That was terrible and took lot of time.

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Use a jigg saw with a tunsten carbide blade. cut slow works great takes about 10min

[cugino]

Stuffing tubes already dried and today i need motor mount installation i already prepared. It was quite frustrating to align stuffing tube with motor mounts but i think that result is good enough. All carbon garbage is on it place. And my epoxy phase is done. There is nothing left to glue with epoxy. U can see, there is very few matterial added. I wanted very light build.

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[cugino]

Everythink is glued on its place, there is time to equip the hull with electrical devices and wiredrive assembly.

It is only my test setup:

Motor Turnigy XK3665 2100KV
ESC: T180
Props: I will start with X436 CNC alu prop, good enough for first testing.

Only i want is to trim wiredrive instalation and tune it to zero vibrations. After zero vibrations procedure is done, i will upgrade to better motors. I expect some suggestions of very experienced FE addicts :-)

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[cugino]

Wiredrive is 2mm wire with 4mm stainless propshaft. Wire is in teflon tube with ketron bearings on eaech end of tube protecting lubricant (silicon oil) to escape outside tube. Teflon tube is fully filled with silicon oil. I hope it will work. I expect little drag from amount of oil, but i hope, that libricant will last several drives, i wish whole day. After whole day i will remove whole wiredrive with teflon and fill it with fresh oil.

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There is prepared power combo waiting for installation. I am very curious how will they perform. Motor wires will be soldered directly to ESC PCB after installation inside the hull.

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[cugino]

Ok, my build is almost done. Well, what do you think? :-)

Next step is paint. I will use 2K Glasurit or Standox car paint. Before that, i have to sand whole hull. I will send pictures after first paint iteration. Hull will be more white next time. :-)

[liteumup69]

Looking good, keep the pics coming!

[sampit]

Nice looking hull, with all the right bits fitted, nice and light it should be flying.
Any further info on the hull, how much does one cost, can another one be build to order? or is it just a one off!

[cugino]

Thank you for your post. I hope it will be light enough to need less power, less capacity batteries a then less weight again.

The hull is only test modiffied protorype now, if it will perform well, there is little chance to do more hulls, but i dont know if any.

[cugino]

Hi folks,

Can anyone give me rough amp draw estimation with following setup (test purposes only)?

Motor: Turnigy XK3665 2100KV
ESC: T180
Batt: 6S A-Spec NanoTech 6600mAh 65-130C
Prop: Alu CNC pro 36mm 1,4 pitch and Octura X442?

I think, it will be under 90Amp per motor with X436. But with X442 i have no clue? I am little warried about XK with X442.

If cat perfomes well, i will spend more money for better motors. Its to early, but what would you suggest. I was considering Tenshock EDF 2240/7, Lehner 1950/6 or NEU 1415 1Y. I am limited to 36mm dia. motors.

Or are there another good options?: MEGA, HET, Plettenberg, Kontronik, Hacker, etc..?

What do you think is the best choice and why? If everythink goes well, i will be looking for most efficient setup for speeds around 150kmh for SAW and 110kmh for bashing. 2x3S pack is only one possible battery configuration. So, my vision is to heve in the end two sets of prop. One set for bashing another for rare adrenalin SAW passes. :)

[TheShaughnessy]

are you gonna spin the props in or out? Why 6s? thought those motors would be better on 4s. 46000 rpm is pretty high, even for a saw set up

[cugino]

I decided to use 6S (3+3) because it is common configuration for my all other RC models. I dont want to have separate battery pack for each model, it is expensive.

I dont understand why is 46000 rpm high, when amp draw is low enough? What issues i can expect?

I have experience for five years with that high rpm setup using Hacker motors. Off course, perfect driveline and bearing is a must. It performs quite well and overall efficiency is satisfiing.

I gonna spin props in for few first tests, then out.

[mtbenjamin77]

I decided to use 6S (3+3) because it is common configuration for my all other RC models. I dont want to have separate battery pack for each model, it is expensive.

I dont understand why is 46000 rpm high, when amp draw is low enough? What issues i can expect?

I have experience for five years with that high rpm setup using Hacker motors. Off course, perfect driveline and bearing is a must. It performs quite well and overall efficiency is satisfiing.

I gonna spin props in for few first tests, then out.

the motor will lose efficiency and create more heat than necessary at that rpm.

[cugino]

Thank you for your reply,

do you have any data? or estimate of efficiency lost? Is there any graph of efficiency showing efficiency lost depending on RPM for any motor?

Thank you.

[cugino]

If i understand correctly, u should use lower KV motor then i originaly intended. But with lower KV i should use much bigger prop to keep same speed. I thing, it is not acceptable, i love small props because of handling.

I think, i should find balance point for rpm/propsize/desired speeds/overall efficiency.

[mtbenjamin77]

I would just aim for about 35000 to 37500 unloaded RPM. remember that is unloaded rpm. I've found in some cases a lower KV motor will spin higher loaded RPM than a higher KV motor in the same setup. The prop really needs to be determined by the hull design & size. Determine the best prop range for your hull and start at the smalledst size and work your way up. It's best to use some type of data logging to determine the current draw as your move up in prop size. You can also analyze your current draw by very closely monitoring your component temperatures. Also, it's been my experience that large CR props do really well on CAT hulls. Because they create more lift than samller props and the CR cancels the negative effects you would find in a single drive. To control your lift, first start with props rotating inward, then outward. determine which configuration worksf best and adjust your stingers to fine tune. Also setup your CG so that you have plenty off room to adjust your battery location to compensate for variable water conditions. The stingers can be adjusted for this but you lose forward thrust the more +/- angle you have on your driveline

[cugino]

New season is going to come, my project is going to continue.

Package actualy arrived home. So here R some pics i must share with you all.

NEU 1415/1Y 2200KV will be installed.

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[ray schrauwen]

Nice choice of motors. Your attention to driveline vibrations will allow you to get as much out of these motors as possible. Many don't realize how much power is lost to vibration as well as the damage to bearings and the heat created.

You are on track, this will be a very fast boat.

Your hull is absolutely beautiful ! Even Hanspeter would raise an eyebrow. Great work!!

[cugino]

Thank you for your post.

I willl do my best to eliminate vibrations as much as i can.

Now i am waitnig for my hull, it is at paintshop now. I am looking forward :)

Hull isnt build by my hands, maybe next time, i hope.

[ray schrauwen]

Was it hard to remove the wires from the T180? How many watts is your solder iron?

[cugino]

Removing wires was quite easy. I used 100watt high kapacity solder iron. Only about 0,8 second was enough to trasnfer heat to ESC connectors. Any part of ESC wasnt heated much. It is very safe to unsolder wires from ESCs PCB.

I prefer to solder motor directly to ESC to avoid high RPM motor-ESC sync. issues and low internal resistance of very short wires, wight comes to play either. Lighter is always better. Any saved gram is lot of saved watts.

[cugino]

Hull is back from paintshop where 2K filler was applied. I already sended the hull again. Here R pictures.

Tomorrow i going to take her to painshop again, where next two coat of base paint will be there. I have already cut vinyl stickers, pretty simple, i like.

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[iridebikes247]

Nice boat I imagine it will run best with props spinning in. Spinning out at high speed I usually run into problems but this is my personal exxperience.

[cugino]

First test will be definetely with inwards rotating props. I am going to do first test with very conservative props 436 only to ensure, the driveline works perfectly and any other problems found last year were solved. Next step will be Alu CNC prop X442. I thing, it will be my final choice for this hull. May by ABC 1616 would work well. I am very curios now, i like high rpm setup.... :-)