need some guidance, first hydro build

[ls1fst98]

picked up an r2 hobbies swifter hydro bare hull for dirt cheap ($1 off ebay)

my plan is to run 4s....not sure if 2s in series or one 4s pack or 4s2p... a lot hinges on my few questions.

1) how do you determine COG on a hydro?
2) i have a castle 1516 2650kv motor, a 120a seaking esc or 180 esc, would this be a good choice?
3) can you use standard x series octura props?
4) was thinking of using the AQ UL-1 hardware with this build since its already black and will fit my theme.

R2 swifter.jpg

[nichismo]

Center of gravity on most hydros is anywhere from .25" to 2" behind the back heel/transom of the sponsons, (obviously depending on size) so generally, a good place to start would be to aim for the end of your turn fin bracket and go from there.

For most applications, two packs to get the desired cell count is usually more applicable given how reliant hydros are on the COG to perform well, and having the option for a parallel setup has its obvious advantages as well. However, we need to know the exact specs/dimensions of the hull you are using to give more accurate recommendations.

Im not too familiar with Castle motors aside from the 2028, so I cant really speak for the motor you listed. However, that is a pretty high KV, and the respective ESC you listed also is rather powerful, I imagine if the boat is anywhere near 25-30" that power setup may be a little too much for the boat to handle (i could be wrong). The popular UL-1 2030kv motor and 60amp ESC is a very very good setup for pretty much all boats this size and would go perfect with 4s lipo configurations, just something you may potentially want to consider.

No reason not to use X series Octura props, I have both 2 and 3 blade X450s for my 1/8 scale, and an x455 3 blade.

[ls1fst98]

Awesome, thanks. After I got the baot in hand I can not fit a 40mm diameter motor, so I do have some aq 1800kv and 2030kv motors as well as some 2150kv.

The boat is just shy of 26" long, 13" at the widest point, 7" wide at transom. Transom is 1.25" tall

[JimClark]

Probably closer to .75 in behind the back of the sponson

Sent from my SM-G900T using Tapatalk

[785boats]

I had one a while ago & ran a Proboat 1500kv motor & the 45A ESC for our Restricted class. With an X645 prop she moved along quite nicely.
So your 2030kv motor with a 440/3 blade or 442/2 blade would make this hull fly.
Here's a vid from a couple of years ago dueling with a Whip. Both had the same setup. Held it's own in my opinion. We were both just testing new boats.
The hydros start at 2:20, but you might enjoy the mono's at the start in our little Boondall Bullring.

[ls1fst98]

Very cool, thanks for the info and sharing the video! Always love watching. Does the hardware from the ul1 make a good fit? Won't be too big on the boat?

[785boats]

I'm sorry I can't help you with that question. I've never used that hardware so I'm not familiar with the size of it.
mine had the hardware already installed.

[T.S.Davis]

It's a 2s boat. Spec power is too much.

[Fluid]

I agree with Terry, 2S is probably a better choice although an experienced boater could run 4S or even 6S with the right motor and prop. Our club runs a "spec" 2S class with specific budget motor and prop, a popular and very competive class. As propped the boats run in upper 40s for one mile heats; propped up mid-50s.

.

[T.S.Davis]

Lehner Basic 5000XL if you can find one. 2s with a 435/3. Weeeeeeee.

A cheap option would be a Fieago 7s......ish on 2s.

[nichismo]

Curious how spec power is going to render the OP incapacitated in driving the boat if its just about the same size as a UL-1 (I mean this 100% as articulated, no way trying to imply anyone is incorrect, im still learning). I know this is like darn near blasphemy from other topics ive read here on OSE, but for my current build with a CT13s, I am running a TFL 4074 2200kv on 6s (yes high RPM to say the least) and its very fast and yet control is magnificent, and this is 31" boat at just under 6lbs. However im sure the design of the sponsons have influence in this case.....

[785boats]

It is just 1" shorter than the UL1 & runs fine on 4s.
The yellow one in the video ran at 77klm (47mph) with the 1500kv motor in oval race trim.
I have another one that I'm testing at the moment with a 3660 2310kv motor & a 437/3 blade prop & she flies quite well on a 4s 5000mah pack (2 x 2s). No video yet.
The only problem with this one is that the moulding is way off in the sponsons. Both sponsons have anhedral in them at the ride surfaces & the left sponson really ploughs in when she corners. You might want to check yours. I'll be making some ride pads to level them out soon.

[T.S.Davis]

Never mind. Sorry I interjected.

[nichismo]

^^^

you gotta be kidding me......

[T.S.Davis]

You get input from experienced guys and immediately discount it.
Jay wrote a book on FE. Its always the same though. Questions get asked. Guys with limited experience answer the questions and argue with any conflicting opinions. Gets old.

Eventually the experienced guys we'll stop interfering. No worries.

[ls1fst98]

Well I've never seen one with 2s, and I'm by no means an inexperienced boater, just never built a hydro. And just because my builds aren't posted here doesn't mean I'm inexperienced as well. It's comments like that that I don't post here. 2s would seem like a waste in a 26" boat. As stated I'm not in any class as its for sport running. It has plenty of room to even fit 4s2p if the weight wasn't an issue.

[ls1fst98]

I haven't discounted anyones input yet.

[flraptor07]

RayR in our club built one of these on 4s and it ran really nice, you might want to get a hold of him.

[ls1fst98]

RayR in our club built one of these on 4s and it ran really nice, you might want to get a hold of him.

Will do, I've also been chatting with bill oxidean on fb, apparently we decided to build the exact same boat st the same time....and he's doing it pretty much the same way as my plan b was, with spec power

[Mxkid261]

I will be curious to see how this turns out I too have been tossing around the idea of a hydro I like the UL-1 but would rather build something

[nichismo]

You get input from experienced guys and immediately discount it.
Jay wrote a book on FE. Its always the same though. Questions get asked. Guys with limited experience answer the questions and argue with any conflicting opinions. Gets old.

Eventually the experienced guys we'll stop interfering. No worries.

First of all, no one is discounting anything.... Heres a little philosophy for you.....Look up Socrates method. It promotes healthy debate among individuals who are mutually interested in something, in order to further cooperate goals and education Even if someone is inexperienced and your the best racer in the world, its just simply foolish to not think outside the box with open minded perspective. The longer youve done something, the more you should feel motivated to change, adapt, improve. However, some people do the exact opposite, and for whatever reason, think that the longer they do something, it somehow grows more correct with time... its really rather silly to say the least.

For you to call anyone that doesnt agree 100% with you as "arguing" is arrogant and insecurity at its finest, and even more ridiculous when you do it in a forum solely dedicated for discussion and sharing opinions for evaluation. THEN to top it all off, you say "sorry for interfering" when you, and everyone else know damn well that you aren't sorry at all and in fact feel the exact opposite of this. Your a grown man dude! why are you getting offended... -_-

Go re read my post, note it hasnt been edited. It friggin says halfway friggin through the first line that im not trying to imply anyone is incorrect and im still learning, half of the comment itself was question!! Why you would call that arguing in the negative sense you imply is beyond me. Your one among a small couple handful of peoples posts on this entire forum that I quickly recognize naturally as an experienced veteran racer. Even moreso that I know your a hydro guy

[nichismo]

You get input from experienced guys and immediately discount it.
Jay wrote a book on FE. Its always the same though. Questions get asked. Guys with limited experience answer the questions and argue with any conflicting opinions. Gets old.

Eventually the experienced guys we'll stop interfering. No worries.

First of all, no one is discounting anything.... Heres a little philosophy for you.....Look up Socrates method. It promotes healthy debate among individuals who are mutually interested in something, in order to cooperate goals and education. Even if someone is inexperienced and your the best racer in the world, its just simply foolish to not think outside the box with open minded perspective.

For you to call anyone that doesnt agree 100% with you as "arguing" is arrogant and insecurity at its finest, and even more ridiculous when you do it in a forum solely dedicated for discussion and sharing opinions for evaluation. THEN to top it all off, you say "sorry for interfering" when you, and everyone else know damn well that you aren't sorry at all and in fact feel the exact opposite of this. Your a grown man dude! why are you getting offended... -_-

Go re read my post, note it hasnt been edited. It friggin says halfway friggin through the first line that im not trying to imply anyone is incorrect and im still learning, half of the comment itself was question!!

[Mxkid261]

Ls1 don't want to jack your thread just have a few questions! What is the best way to check COG? Get all your stuff positioned in the hull and then set it on like a piece of steel rod and let itself balance out? I'm about to pull the trigger on a DF 24 vortex from OSE store for my first hydro so your build will be a lot of help. Thanks!

[revoltrunner]

Here's a pic of my Vac-U-Pickle 26" x 13"
Proboat 1800kv , aquacraft 60amp esc , X642 prop
2 5000mah 2s 50c batteries

[jaike5]

Lmao...

Cheers, Jay.

[ls1fst98]

Lmao...

Cheers, Jay.

just curious whats funny??

boats 95% complete. will post pics if anyone else really cares, or in case anyone still thinks its a 2s boat....

[jaike5]

I've known Terry for years, and was visualizing the facial expressions !! Terry, Fred, Jay, Tony, (sorry if I missed some one) these guy's are wealth of information and a sure way to save on expensive mistakes. Terry has borrowed parts from me, lent parts to me just to keep us on the water and racing , from tape and grease to motors and esc's his wealth of information there for the asking ...and I do ask. Anyone can over power a boat , but to be so flippant to pass on the information that was requested is crazy.

Just my .02

Cheer, Jay. (not the same Jay as the fore mentioned)

[Coug90]

I've known Terry for years, and was visualizing the facial expressions !! Terry, Fred, Jay, Tony, (sorry if I missed some one) these guy's are wealth of information and a sure way to save on expensive mistakes. Terry has borrowed parts from me, lent parts to me just to keep us on the water and racing , from tape and grease to motors and esc's his wealth of information there for the asking ...and I do ask. Anyone can over power a boat , but to be so flippant to pass on the information that was requested is crazy.

Just my .02

Cheer, Jay. (not the same Jay as the fore mentioned)

I'm confused. Which guy is Terry and why would someone be crazy to pass on his information? Did you mean passing it on to someone else to use, or passing as in considering another option and not going with his suggestion? I'm just trying to follow along. It looks like the guy doing the build said that his plan was for a 4s setup from the beginning and was asking questions about other things he hadn't already decided on. Were feelings hurt when the builder didn't change his plan based on someone's opinion? Is that where this thread went? Time to check our egos at the door. I don't think that was the builders intent when they started it. Anyway, I like the X series props and I see no reason not to go with them on this project at least initially. They seem to be a prop that you can mess with to fine tune the performance and handling of the boat when you see what it needs. I don't have much experience with the smaller, prefabbed hydros so I can't really be of much help on the other questions. Enjoy the build and please don't worry about us. We'll be just fine, regardless of what you decide to do.

[ls1fst98]

I'm confused. Which guy is Terry and why would someone be crazy to pass on his information? Did you mean passing it on to someone else to use, or passing as in considering another option and not going with his suggestion? I'm just trying to follow along. It looks like the guy doing the build said that his plan was for a 4s setup from the beginning and was asking questions about other things he hadn't already decided on. Were feelings hurt when the builder didn't change his plan based on someone's opinion? Is that where this thread went? Time to check our egos at the door. I don't think that was the builders intent when they started it. Anyway, I like the X series props and I see no reason not to go with them on this project at least initially. They seem to be a prop that you can mess with to fine tune the performance and handling of the boat when you see what it needs. I don't have much experience with the smaller, prefabbed hydros so I can't really be of much help on the other questions. Enjoy the build and please don't worry about us. We'll be just fine, regardless of what you decide to do.

thanks, and it appeared to take a turn when i didnt want to make it a 2s boat. i already had all the other stuff to make it a 4s boat from motors to escs. it is in the size range of most the other 4s hydros ive seen built or offered so thats why i bought it.

thanks for the input and i will probably start with a 440 or 442 and see how it goes. im thinking im overdoing it a bit on the esc with a 120a dynamite but its nice to have the headroom and again it was something i had already.

and i dont worry about things like what people say...its the internet...gota have a a thick skin.

thanks for addressing my initial questions, ill post a vid of the maiden run which should be soon. just have to cut flex and sort out waterlines and its ready.