Brushless Wild Cat?

[FighterCat57]

I have a 500' body of water really close to me that's small for a fast boat, but fun in the wild cat.

What I want is to use my standard transmitter/receiver setup...

... 5+ more MPH and 20 minutes of run time.

It's pretty clear that the mounts can be taken out and the motors can be changed and there's room for an ESC, maybe two...

What I don't know is the Kv of the stock motors and the size?
What kind of brushless setup would work?

Much smaller than I've worked with in the past and probably best to ask before tearing in to it. =)
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FX-1 (http://www.toyota-wiki.com/wiki/Toyota_FX-1)

[FighterCat57]

Still looking for the Kv of the stock motors. They are Aquacraft T270
Can Diameter: 24mm (0.95")
Can Length without capacitor and shaft: 30.5mm (1.20")
Overall length including capacitor and shaft: 57mm (2.25")
Shaft Length: 10mm (0.40")
Shaft Diameter: 2mm 0.08")


I think it could be a fun little boat with twin brushless.


If I can get enough power out of it, I'll make it my rescue boat!
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BMW M51 HISTORY (http://www.bmw-tech.org/wiki/BMW_M51)

[FighterCat57]

OK. Parts ordered! This is going to be a crazy little thing!

The next question, is prop size. Tiny little guys, anyone know if I can find a counter rotating pair?

Looks to be an M3 nut. I'm guessing a 1/8th prop will work.
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Daihatsu Taft History (http://www.toyota-wiki.com/wiki/Daihatsu_Taft)

[forescott]

How about the octura x430 left and right??

[FighterCat57]

How about the octura x430 left and right??

Hmm. I think those would work.

I did find out that these are 3mm shafts, so again, I think a 1/8th is in tolerance (.17mm)

I'd really like to stick with plastic and cheap though. I have a set of 32mm counter rotating props that I think would work, however they are for 4mm shaft. I think I can find a 4mm OD, 3mmID tube, but haven't looked yet.
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Medical Marijuana (http://medicalmarijuanacard.info)

[forescott]

Hmm. I think those would work.

I did find out that these are 3mm shafts, so again, I think a 1/8th is in tolerance (.17mm)

I'd really like to stick with plastic and cheap though. I have a set of 32mm counter rotating props that I think would work, however they are for 4mm shaft. I think I can find a 4mm OD, 3mmID tube, but haven't looked yet.
AAAAAH! venom props!

[FighterCat57]

AAAAAH! venom props!

Yep. Cheap $3 props. That reminds me, I have to look up 3-4mm tubing.
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VAPIR ONE REVIEW (http://vaporizer.org/reviews/vapir-air-one/)

[FighterCat57]

Perhaps a #128 inside of a #129 brass tubing?
http://www.offshoreelectrics.com/proddetail.php?prod=dh-ks-brass-tb
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America'S Next Top Model Forum (http://www.tv-gossip.com/americas-next-top-model/)

[FighterCat57]

OK, got the prop thing figured out. Just waiting on Hong Kong Post!

Have the coupler thing all set as well.

In case of failure, I have an alternate configuration in mind... HobbyHot has a 60a esc/motor combo with a water cooled inrunner that is very similar in dimensions, but has a larger motor shaft. Looks like it will bolt right up. My biggest worry then would be controlling it. Way too much motor for this little guy. Who knows though, it might make it really fun! It's about $80 bucks though, so will try the bolt in $30 Turnigy solution first.

My speed/time goal is 30 mph with 15 minutes of run time. Either the Turnigy or the Hobbywing setup will do the trick for sure!
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Ford Xw Falcon (http://www.ford-wiki.com/wiki/Ford_XW_Falcon)

[turboed13b]

care to provide some links of the parts you are using?

[FighterCat57]

care to provide some links of the parts you are using?

Sure!

Plan A:

2900Kv Inrunner drop in replacement
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=4197

35-40a ESC for 2900Kv inrunner (2-3s Lipo)
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6461

Plan B:

SwangHobby(HobbyHot) 60a ESC/Water Cooled motor Combo:
http://www.hobbyhot.com/swanghobby-marine-3600kv-brushless-motor-flyermate-atlantis-60-c-281-p-1-pr-2307.html


I plan on using the 32mm Counter Rotating Venom Propellers with a #128 brass tubing insert to fit as 1/8th props. I'll experiment with both rotating inwards for performance and outwards for stability.
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IOLITE VAPORIZER (http://vaporizer.org/reviews/iolite)

[FighterCat57]

Ha! Swang's out of the 60a/Inrunner combo! Guess it was a good deal!

[FighterCat57]

The drop in HK motors should be here tomorrow!

Nothing fancy, 2s and little 32mm props to start. The goal isn't massive speed runs, rather a good increase in speed and a nice long run time.

[FighterCat57]

The babies are heeeeeeeeeere!

So tiny!

Looks like I'll have to shave in a flat spot on the shafts, but otherwise, good to go!

I'll get some photos of the mounting/installation process. The aluminum cooling coils should fit right on.

The special instructions on these ESC's say 2s only if over 2000Kv, which I'm at 2900Kv on these lil guys. So, 2s it is. There's room for two 2s 2200kv lipo packs, so will see how the power/run time situation goes.

[FighterCat57]

OK, parts in! However, in a 50/50 chance I setup the props spinning outward.

Hmmm, should I set them up counter rotating in or out?

[forescott]

Good question! I thought of reversing the rotation on my ekos to see how it performs.

[FighterCat57]

This little mofo is awesome! I may go up to the 36mm props!

Didn't manage to get any heat out of it messing around on 2s w/32mm props. None, temps in the 80's.

I left the props counter rotating outwards. This is supposed to help keep the tail planted in the water and will hopefully help with a more forward COG as the motors and ESC's put the COG forward more than I wanted.

Didn't have time to put it in real water, just the pool, but it literally jumped on plane and launched like a hole shot!

Don't know if I can get a GPS on it, but I'll try sometime.

Very cool project!

Parts list:

2 x 35a HobbyKing ESC's (http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=6461)
2 x 2445 2900Kv Inrunners (http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=4197)
2 x 32mm Venom 32mm CR Props (Venom Racing 3 Blade Prop D32 P1.4 CR EKOS VNR1982 & D32 P1.4 EKOS VNR1981)
2 x 2s1p 2200Mah 20c Lipo Cells (http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=6540)
1 x #128 brass tubing to shim the props

Total upgrade cost including Lipos: $95 plus Rx... :w00t:

[turboed13b]

how do you put the esc's into the reciever? real boats have their props rotating outward. are you running two batteries or just using one as an extra?

[FighterCat57]

how do you put the esc's into the reciever? real boats have their props rotating outward. are you running two batteries or just using one as an extra?

I used a Y adapter with the red wire pulled on one of the ESC sides. (prevent BEC overlap)

The battery packs are in parallel, 2s2p 40c 4400Mah total configuration. A full size 150 x 50mm battery would not fit, so I used two smaller format lipos instead.

[FighterCat57]

OK, one of you smart guys should have told me that the cables lay in the same direction and switching them to counter rotation, I would need to get a cable laid in the opposite direction!

I noticed a change in drive sound and quickly pulled the drives, the cable is OK, but I quickly noticed it was laid in the opposite direction as I was using it.

So, add a new drive cable to the list!

I think Jeff can make me a pair. His cables are top notch. =)

[FighterCat57]

The cables, notice the odd looking one.

[FighterCat57]

Approximate measurements:

3mm hard shaft, 1.2mm cable, 18mm long

Or... 1/8th & 5/64ths 7 inches long

[FighterCat57]

...or I could just get some .047 music wire, some silver solder and build a set myself... =)

[turboed13b]

will the .098 flex cable work?

[FighterCat57]

That's like double the size. The current cable is .047 and the couplers are setup likewise.

[turboed13b]

a lot of people use them in the mini rio's i will check later to see if the tubes are the same size.

[FighterCat57]

a lot of people use them in the mini rio's i will check later to see if the tubes are the same size.

I'm pretty sure they will fit in the tubes, they are #128 sized tubing.

It's the couplers, they would need to be larger to accept the larger wire.

Although, that's easy to drill out if there's Left/Right or wire drives already available for 3mm (#128) brass stuffing tubes.

[turboed13b]

anything new?

[FighterCat57]

Yeah, I got the 047 wire and soldered up a set of drives!

The only problem is the stock tubing is bent like and "S" and the wires bind up too much.

I have to make a decision to either scrap the wire drives and go back to the cables without counter rotating props... or... straighten out the brass tubing for a clear shot for the wires.

Which... I'm most likely to heat up the epoxy and replace the brass with a straighter tube. Since it's #128 brass, I happen to have a couple of pieces of it right here.

Just time now... My other half is off for a few days, so busy doing other stuff. =)

[FighterCat57]

Photos

[turboed13b]

the thing i found when i put 370 brushed motors in mine is the boat turn to the right i had to offset my battery and use the rudder to make it go straight again. i say stick with counter rotating props.

[FighterCat57]

the thing i found when i put 370 brushed motors in mine is the boat turn to the right i had to offset my battery and use the rudder to make it go straight again. i say stick with counter rotating props.

Ah, cool. Good to know! When I get some time again, I'll get the brass straightened out and the wires running smooth and she'll be good to go. The ESC's basically have to be mounted inbetween the motors to help keep the cog towards the back. Can't wait to run it in real water. =)

[FighterCat57]

Ok, counter rotating and ready to go! Had some time while I was watching paint dry today. Had to straighten out the brass tubes for the wire drives to spin freely. I moved the wooden supports and re-glued them further towards the motors. They had the stock tubes bent like and s curve. Don't understand why? :confused2:

Against my better judgement, I decided to do a bench test and open her up to see if I could generate some heat! I would rather have it fail on the bench.

None, really. Didn't get hot at all, in fact, was kinda fun seeing what I could blow off the workbench with it. Good mount of air flow. Had some fun for a few minutes with my little remote control fan.

I'm sure I'll get some heat with the props in the water. =)

[FighterCat57]

Ah, thought I would add... the cheapie ESC's have a slight delay on acceleration then catch up with a punch... like they are building up and then go.

[FighterCat57]

Of course it broke a shaft today... I think 047 is a bit too small of wire.

Not sure what to do at this point. It would be really great to find a left hand lay cable!

For now, I have a new pair of drives coming and I'll try the stock props both CCW and see how that goes.

It was a rocket! For a minute.
=)

[damfurst]

I think the wire broke because of the s in the tubing. Wire drives can take a slight curve, but an s would be bad I think. You might try Jeff Wohlt he may be able to make you a left & right lay cable for it. Defintly go to something bigger than the stock drive cables. I don't think they'll take the power of the bl motors. Jeff Wohlt can also make motor couplers.

[FighterCat57]

Yep. Already talked with Jeff. He doesn't have the 3mm drives.

I am going to try to straighten the brass some more. I really think they are breaking like you said, because of the double bend, even if reduced to only a slight bend, it's still an s and that's where the wires are breaking.

I guess the way to do it is to heat the tube up with a soldering iron and loosen up the epoxy? I've never messed with removing epoxy like this. If I can get it out, I can replace it with a straighter tube. It's just #128 tubing.

[FighterCat57]

New cables are in. Might get the prop wet this week!

[FighterCat57]

The port side wire snapped and put a slight bend in the shaft. Just enough to make some vibration.

The ESC fried, so now there's only 1 ESC working. So I pulled the Rx for another project and shelved it.

[FighterCat57]

Updated photos by request:

[FighterCat57]

More;

[FighterCat57]

Next HK order, I'm planning on another ESC & motor. Will give it another try. Was wicked fast when it ran the first time. =)

[FighterCat57]

This ESC and motor are "drop in".

Motor:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=4197

ESC:
http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idproduct=6461

[forescott]

You're esc shows a maximum kv of 2000. The motors are 2900kv. Is that why one burnt up??

[FighterCat57]

You're esc shows a maximum kv of 2000. The motors are 2900kv. Is that why one burnt up??

Max 2000 on 3s. 2s doesn't matter.

ESC burnt because I plugged it into a BEC and fried it since it already has a BEC. :doh:

[GTX]

Is there such thing as a single ESC w/ BEC that will run two motors ?

[FighterCat57]

Is there such thing as a single ESC w/ BEC that will run two motors ?

So far, no. But I've gotten two ESC's to share the same cooling block and shrink wrapped them together successfully. When the other ESC comes in, I'll post some photos of it going together. It takes up much less room shrinked up as one unit.

[GTX]

Hmm that is too bad....but how about this.

two brushed Frenzy 370's one brushed ESC with the two motors running off it in parallel ?

I think the airplane guys do this ?

[FighterCat57]

yeah, as far as I know, you can run two motors off of a brushed ESC. The stock wildcat uses an ESC/Rx all in one with two brushed motors. The generic brushless ESC's are only about $10... http://www.himodel.com/electric/HiModel_GX_Seires_30A_Brushless_Electric_Speed_Con troller_Type_GX-30A.html

OSE has the water blocks to cool them. Mount them back to back and you're good to go.

[turboed13b]

Hmm that is too bad....but how about this.

two brushed Frenzy 370's one brushed ESC with the two motors running off it in parallel ?

I think the airplane guys do this ?

Im runnin the frenzys with the mlst esc i need to run smaller props as the battery gets hot.

[Mash13]

I love these mini boats! I have a mini C, its been a pain in the butt with water ingress and the ABS is cracked up. Pity these little boats that look so scale cant be easily modded. your build looks great!