new skunkworks cat: twin outrunner build

[bea5017]

jus got my new skunkwork 32"cat. very nice scott, came with no damage, couldnt be happier. thinkin about two of these http://www.innov8tivedesigns.com/product_info.php?cPath=21_25_49&products_id=396 on 6s, whatcha think or two of these http://www.innov8tivedesigns.com/product_info.php?cPath=21_25_65&products_id=314 on 5s

[j.m.]

eh...

How ya going to cool them?

[bea5017]

Built in fan, only pulling 25 amps, got high temp magnets, not all that worried, but ima try for a water cooled mount but four it will fit

[j.m.]

You think your only going to pull 25 amps??

What prop are we running here?

[wakeboardfusion]

I am new at this, but i can almost bet you will have a heat issue.

[bea5017]

i am awear of the heat issue it has a built in fan, with magnets that can take upwards of 350 degree f, the boat is only going to be ran on short runs so im not that concerned, the esc will be water cooled, and like i said i am going to try and get a water cooled motor mount. the smaller motor has a max of 25 amps, on 6s for around 550 watts apeice, or at least according to the specs.

[j.m.]

so 1100 watts on a 32" cat without water cooling is like putting a weed whacker engine on a pontoon boat and expecting it to do 50mph.

[bea5017]

1100 watts is approx equivilent to an 540 xl motor which will easilly push a 32 cat

[bustitup]

I think your wanting to run scorpions is a great idea

check out Jim Williams site for scorpion motors and outrunner cooling motor mounts.......his prices are cheaper than the site you linked and he gives an extra $5 discount to people who register on his site

[bea5017]

Thanks bustitup, do u think I should go wit the larger ones (1900 kv) on 5s ?

[bustitup]

Thanks bustitup, do u think I should go wit the larger ones (1900 kv) on 5s ?


perfect

[wakeboardfusion]

what about a metal cooling coil just to be safe?

[bea5017]

tough to do wit an outrunner, coolin the mount bi=out the best u can do

[bea5017]

finally got my motors n mounts. sry about the poor quality pics, it was the best i could do. hopefully more to come waiting on hardware. keep up the motivzation

[ozzie-crawl]

i run a 3026 1900kv on my tunnel,i cant fit a data logger in but going of mah used it pulls a average of 66 amps on 4s running a m642. running 5s on x442s shouldn't draw to many amps i dont think.mine being in the wind doesn't get past 40c after a few min run time.
the scorpion in runners will be released in the next 2-3 months,more motors :banana:

[bea5017]

what kind of speed do you think i will be around with thats settup?

[ozzie-crawl]

well according to Fecalc (if its to be believed?) on 5s a single 3026 1900 kv would pull 117 amps and speed would be 50 mph. on 4s it would be 84 amps 42 mph.
running twins should drop the amps but 5s would still be pushing the motor fairly hard

[befu]

I am finding this one interesting as I will be building one of these this fall probably.

There are some incredibly fast boats out there, but the power draw is staggering in these things. FE has come of age, makes you wonder what we will see two years from now.

Anyway, I think there is a drastic range of power options, and we have to remember that while speed is linear, the power to get there is exponential.

If you look at the Ekos (bad example, I know!) power system, you have twin drive pushing 32 or 36mm props on 3s. Or 4s with the 32mm props if I recall. On 3s this should be +/- 40mph depending on prop, bumping 50mph on 4s - 32mm. (Not firm numbers, going off memory but it gives a ball park)

I also run a 24" mono on a turnigy 3650-2300, 3s, 38mm prop. Goes great, fun sport boat and runs on 22 amps average which is 244 watts. Haven't run it on the eagle tree yet, but that is averaging things out from run time, all temps are very cool. I would think I should be running low to mid 30's.

So back to this cat. I do not see why you could not run a 32" cat on 1100 watts. You just have to match the motors kv and props. 1900 kv on 5s is 35,150 rpm. Definately up there, but OK. With props in the 32 to 36mm range, speeds should be low 40's to upper 40's. You are talking 1.5 HP! Heck, the stock weed homelite weed eaters were a little under 1.5 HP I think and they pushed a 55" mono or cat nicely, weighed a lot also.

going from mid 40's to mid 60's is another story. Depends on what the user is looking for in speed, cost and run time.

From an engineering prospect the maximizing speed per watt is interesting to me. I love boats that are in the 20 to 40 amp range, cheap equipment! Opps, just noticed the outrunners he went with are 80 amps apiece on 5s. That max's out at almost 3,000 watts in this boat, out of my league! Doesn't look like a sport runner like the EKOS, should be a fantastic fast boat.

Brian

[bea5017]

got my stinger choice down to 2 http://cgi.ebay.com/aluminum-adjustable-stinger-drive-for-4mm-shaft_W0QQitemZ290369428009QQcmdZViewItemQQptZRadi o_Control_Vehicles?hash=item439b5dda29 or.... http://cgi.ebay.com/Adjustable-stinger-drive-for-4mm-cable-for-rc-boat_W0QQitemZ140313080206QQcmdZViewItemQQptZRadio _Control_Parts_Accessories?hash=item20ab4fb18e cant pick leanin twoards the silver 1

[j.m.]

I would go with a stinger that has a proper bushing and allows the use of easy to find US Customary cables.

I read a quick review on that black strut and the guy said it worked great IF you replaced the bushing and machined a little insert to allow a .130" cable. He had to chuck a speedmaster bushing on his lathe to make it the right diameter.

Jon

[Eodman]

they also sell a stringer for 3/16 ths shaft for $31.00 comes with ceramic bearings! A little more money but maybe less headaches down the road!

[bea5017]

i do want to use a 3/16 shaft.. however it is hard to find one that has a small enough mounting bracket (less than 1" height). i was thinkin about just drilling it out and putting in a 3/16 bushing.

[bea5017]

Eodman, Link Please?

[gni5002]

Ben i love the setup cant wait to see it once its all together. you got to do a real nice paint job so it looks as sweet as it gunna run.

just remember to watch for the pipes under the water.:beerchug:

[bea5017]

too much swine

[tiqueman]

got my stinger choice down to 2 http://cgi.ebay.com/aluminum-adjustable-stinger-drive-for-4mm-shaft_W0QQitemZ290369428009QQcmdZViewItemQQptZRadi o_Control_Vehicles?hash=item439b5dda29 or.... http://cgi.ebay.com/Adjustable-stinger-drive-for-4mm-cable-for-rc-boat_W0QQitemZ140313080206QQcmdZViewItemQQptZRadio _Control_Parts_Accessories?hash=item20ab4fb18e cant pick leanin twoards the silver 1

Ive got the black ones.. Took 45 seconds each to modify them to accept a 3/16 shaft. Very Very easy to do. Cordless drill and a 1/4 inch bit. If you have a drill press, then your one up on me and it should be even easier.

[bea5017]

change in plans waiting to see if i can get some modified struts. before & after so i can cut them and make them fit should be even easier for the machinest too

[Eodman]

If you look at the ebay page he is selling the two you mentioned then click on his store site or other items for sale you will find them!

[bea5017]

looks like this wont be a problem :) hopefully i can get them made for a 3/16 shaft aswell

[j.m.]

Ive got the black ones.. Took 45 seconds each to modify them to accept a 3/16 shaft. Very Very easy to do. Cordless drill and a 1/4 inch bit. If you have a drill press, then your one up on me and it should be even easier.



Really? That sounds awesome... What size flex did you use and how deep did you drill?

Jon

[tiqueman]

Really? That sounds awesome... What size flex did you use and how deep did you drill?

Jon

I used .150 and drilled about 3/8 deep into the tail end of the stinger. Then made a bushing using 7/32 and 1/4" brass. The 1/4 inch is cut the same depth as the drilled stinger. 7/32 is as long as the 3/16 shaft. Works great.

[bea5017]

got a little bit of work done, came out decent for first time layin up cf.

[gni5002]

that sheet you used for the motor mounts is sweet. should make it easy to get the motors in and out to

[obrien008]

good thing we pulled that first sheet haha, looks alot better now..

[bea5017]

that was a complete desaster lol

[Xfactor]

1100 watts is approx equivilent to an 540 xl motor which will easilly push a 32 cat
A 540 xl is gonna pull alot more than 25 amps and can put out alot more than 1100watts and is gonna pull more like 1900 watts on a x440
not saying it wont work though.

[bea5017]

read the post. i didnt even go with xls.. and i wasnt talking about the xls pulling 25 amps was refering to a small outrunner motor. fyi my 8xl pulls approx 80 amps * 14.8 volts = 1184 watts...... i know they can produce more power jus depends on the wind and cell count

[bea5017]

ordered my rudder and stingers today, who knows how long they will take to get here from china... http://cgi.ebay.com/Aluminum-rudder-for-fast-electric-87mm-blade-height_W0QQitemZ300417231701QQcmdZViewItemQQptZRad io_Control_Vehicles?hash=item45f2432b55 http://cgi.ebay.com/aluminum-adjustable-stinger-drive-for-4mm-shaft_W0QQitemZ290369428009QQcmdZViewItemQQptZRadi o_Control_Vehicles?hash=item439b5dda29

[tiqueman]

ordered my rudder and stingers today, who knows how long they will take to get here from china... http://cgi.ebay.com/Aluminum-rudder-for-fast-electric-87mm-blade-height_W0QQitemZ300417231701QQcmdZViewItemQQptZRad io_Control_Vehicles?hash=item45f2432b55 http://cgi.ebay.com/aluminum-adjustable-stinger-drive-for-4mm-shaft_W0QQitemZ290369428009QQcmdZViewItemQQptZRadi o_Control_Vehicles?hash=item439b5dda29

I really hope to hear good reviews on that rudder. I started w/ almost the exact rudder on my twin Hotr. It didnt like it at all. It was very loose and very "fish taily" out of the corner, when it would go thru a complete corner. Mostly it would just spin out. I ended up w/ the one Steven sells, http://www.offshoreelectrics.com/proddetail.php?prod=ose-80085 , only using the mount and rudder and wow what a difference it made. I also think it helped a lot becasue its a bit further back. :confused2:

[gni5002]

i see you decided to go with the stingers instead of the struts what the deal

[obrien008]

any updates? you better get moving cause mines almost done :laugh:

[bea5017]

hardware should be in sometime nxt week, convently the same time finals are over.... should have some progress in a week or so. once the hardware comes in ill be able to mount my motors too

[bea5017]

what props for this thing 42's 45's? do the outrunners like more pitch? blades? diameter? i no nothing about props

[bea5017]

servo layout. i want to to a pull pull setup with steel cable. anyone no and good servo arms that would work.

[j.m.]

Your standard two arm servo horn should work great. Just make sure the distance from the center pivot to your holes is EXACTLY the same on your rudder and on your servo arm.

Jon

[blackcat26]

I can't wait to this this baby in action! Being outrunners, you might be able to swing some c/r 447's. I think you will be pleased with the speed. Be sure and note the motor temps. when you run also I am very curious. From the description of the motors, it sounds like they would almost have to be on fire to overheat......:rockon2:

[BakedMopar]

If that stinger is 31mm high its not going to fit.

[bea5017]

its 25mm

[BakedMopar]

Cool. Did you get it yet? Looks to be higher than wider. Could just be the pictures also. Anyways nice build dude:thumbup1: Interested in how those outrunners will work.

[bea5017]

nah bot yet should be in sometime this week, then i can mount the motors or somethin... tryin to work out my water pickup situation, i need 4 rudder has none.. what kind do you guys use for max water flow?

[obrien008]

These stingers are way better, plus they use regular size cables

http://www.etti.com.hk/product_info.php?cPath=10&products_id=104

For cooling just get those double flush through hull pick ups from offshore

[bea5017]

idk bout the through hulls man

[BakedMopar]

Those ettis are 4mm. Even if you get the ones from HK that they advertise for 3/16" they are not. That's what I use on my cat.

[tiqueman]

These stingers are way better, plus they use regular size cables

http://www.etti.com.hk/product_info.php?cPath=10&products_id=104

For cooling just get those double flush through hull pick ups from offshore

I use the aluminum flush thru hulls. They work great! :thumbup1:

I also have the stingers you got and am 100% pleased w/ them. No doubt you will be happy w/ your purchase.

I dont see, other than style, what the diifference is in the stingers.. they both are for 4mm shafts? Or am I missing something? The HOTR stingers are super easy to adapt to 3/16. It takes a 1/4" drill bit and about 5 seconds per stinger and your done.

[bea5017]

the only reason in hesitent to get them is i have no room from the motor back... its already gonna be so crampt..

[tiqueman]

I thought the same while building mine, but they fit. I used the singles though. Plenty of room. I could see the double inlet being a bit tight.

[bea5017]

few pics

[bea5017]

more

[bea5017]

even more

[bea5017]

last ones

[tiqueman]

Look great Bea! Nice little mod on the rudder bracket as well.

[bea5017]

what u guys think of the flex shaft angle? and my dual water pick up are approx centered in the rear ride pad hopfully that is far enough back?

[tiqueman]

uhh I didnt even notice that. Looks kinda drastic in the pic. You really want your motor to be inline w/ the end of the stuffing tube. It looks as though the flex continues to bend to get to the moter. Thats going to cause a lot of heat and stress on that part of the flex and may cause premature failure.

Pick ups shoudl be okay where they are, but you wont know for sure until you run. Ive got mine a bit further back and they work well.

[blackcat26]

Scott's right about the stuffing tube. Ideally when you grease the flex and send it into the stuffing tube it should go perfectly into the coupler with no help.....I deff. would address that issue before running it. Less headache in the long run.

[bea5017]

really think its that bad? it spins free and i plan to lube it b4 each run maby anin run oiler? i really dont wanna rip it out and the space is so tight i dont think i can make it much better

[blackcat26]

You can always try it first, but I think you may not be happy with the results and will always wonder how much faster it would be with that area fixed. (at least thats what i would wonder)

[bea5017]

true, if i notice the stuffing tube gettin hot or any drive shaft wear i will redo them..

[tiqueman]

Mine run in perfect. I run a liner and my tubes get pretty hot. If it were me.. I would take the time now and re-do them. It will be worth it in the long run. Theres nothing like puting all the time and effort into a beautiful build such as you have to find something you thought may happen, happen. I do not see that bend being a good situation at all. Ive been there, so close to done and want to get it wet.. but your not going to be happy if it does something like snap in a way and lock your motor quickly, then theres goes an ESC and possibly a motor? Or rips apart and twists the stuffing tube and damages your hull. Id rather be safe than sorry. Mishaps are not always just an easy fix.... Just my .02

[tiqueman]

Kinda hard to see but you get the idea....

[bea5017]

damn nice... my mounts put the motor alot higher up and i wanted them as far back as possible to allow me to put the 2 heavy 5s 5800 in each sponson to keep the weight a lil lower in the boat as opposed to having them in the tub.. that being said the stuffing tube has too have a lil more bend in em... i really really dont wanna rip both the mounts n stuffing tubes out, i just put them in! they spin free, im thinkin some sort of active lube system, i got a few ideas and i think i got the room up front... we will see. i have no teflon in my btw.. and tique where did you get those servo arm linkages i like them alot, and is that a cable or wire?

[tiqueman]

I dont think you have to remove the motor mounts, just snake the tubes back down towards the motor shaft rather than it stopping in an upward direction. I dont think it will matter how you try to lube it, that edges where the flex leaves the tube is not going to be good. Its going to produce a lot of heat and wear. It may spin free, but that doesnt mean its not going to have a hot spot. I learned this the hard way on a gas cat, but at the strut end. I broke 6, 30 dollar cables all within 15 minutes of thier first run until I finally let the LHS look at it and he found the spot where things didnt quite line up. I fixed it and since then am on the same shaft for a few years now. IMO it would be well worth the couple hours to remove and re-do.

The linkages are from Dubro

http://www.google.com/products/catalog?q=dubro+swivel+link&rls=com.microsoft:en-us:IE-Address&oe=UTF-8&rlz=&um=1&ie=UTF-8&cid=13145857597600799897&ei=4lP7S4rzJ8P38Abm5unxAw&sa=X&oi=product_catalog_result&ct=result&resnum=3&ved=0CB8Q8wIwAg#

And its running pull pull on aircraft aileron control cable from Sullivan

[obrien008]

Looking sick ben, sticker is facing the wrong way but the paint job is awesome. Shouldnt be too hard to redo them, still waiting on ESCs anyway, might aswell fix it while your waiting anyway. You gotta get it done already so you can run it with my new one before I break it.

Also Tiq, are those green gromets on end of your stuffing tubes used to keep water out? Whered you get them?????????????

[bea5017]

too late lol

[tiqueman]

Looking sick ben, sticker is facing the wrong way but the paint job is awesome. Shouldnt be too hard to redo them, still waiting on ESCs anyway, might aswell fix it while your waiting anyway. You gotta get it done already so you can run it with my new one before I break it.

Also Tiq, are those green gromets on end of your stuffing tubes used to keep water out? Whered you get them?????????????

:laugh: Yes, they are to keep water out and keep grease sling out for the most part as well. They are actually greenish blue from the color of the grease and they are :spy: cut pieces of silicone water cooling line.

Heres another pic

[j.m.]

If it really messes up, just move the motors forward and that'll give you less angle on the shafts.

[HYDROJERRY]

I do the same as Tiq with the stuffing tube, the rubber hose works well, finding the right size to not cause to much drag on the flex sucks..

[BakedMopar]

If it really messes up, just move the motors forward and that'll give you less angle on the shafts.

:iagree:

I have run the batteries both in the sponsons and on the tunnel. IME it made very little difference. It actually turned better with it on the tunnel.

I would try it first and see what happens.

[bea5017]

boat is pretty much done jus waiting on batteries n esc's that should be here in a few days. lookin for a little advice on cg anyone withthis boat please chime in... i also got the hull cleared with a heavy duty automotive clear when i got my truck bumper fixed... should i rough up the ride pads?