Best Whiplash Lipo Location

[detox]

I'm ready to build my Whiplash 20 powered by a NUE 1515 1y and was wondering where is the best location to mount Lipos for best balance. I thought about using these two 30c 4s 3700mah packs wired parallel for a total of 7400mah. http://hobbyking.com/hobbycity/store...idProduct=9506
These fit very easily in the 4" x 4" location I have outlined in red. Is there a better option?

[detox]

I also have two Hyperion G3 packs (4s 3300mah) that are very close to the same size that I use in my UL-1 powered by a Nue 1515 1y.

[sailr]

Myself and others in our club are running two 2S 4700-5500's in series. You'll have to add dead weight with anything less! The lipos fit great right up front. Look for the Whiplash Builds on this board.

[crabstick]

I did mine a little different, Motor right up the front and cells behind, I can get good cog on 4 and 6s setups like this

[eboat]

Where were you going to put the motor in front of the lipos or behind ?
There is alot of boat behind the sponsons and you will need to keep as much weight near the front

[Jeepers]

First remember Brian recommends the CG at 1 inch behind the sponson with a RTR weight of 5lbs this will change the heavier the boat is.

In my opinion there is 2 much weight in the nose with 4s2p, it handles the corners poorly actually loses speed, I tested it, 2p did not go back in after the first run.

Here is how I set my Whiplash up: 4s1p 6500mah Hyperion cells, Neu 1521 1.5d. hydra 240 set at low timing, water cooling on the ESC ONLY, it weighs 7lbs 7oz on the water.

This boat finished overall 3rd at the 2009 Nats in P Sport hydro,not bad for a boat I finished 1 week prior to Nats and had very little tuning on it!

The Whiplash is my favorite boat!

[detox]

Jeepers,
I will mount my motor about the same location you mounted yours in picture. That way I can use the side locations like yours or up front in front of motor

[LuckyDuc]

I did a significant amount of CG testing with mine, and found that the packs needed to be as far forward as possible. I used 2 x 2cell 5000mah 30c packs in series in mine. If you look at the link below you will see that I still had to add 3oz of lead to each sponson tip to get the CG close.

When you get to the point where everything but the top decking is glued on, install everything and play with the layout until you get close on the CG. I'd be willing to bet some $$ that your packs will end up in the front as far as possible.

Pic https://forums.offshoreelectrics.com/...4&postcount=58

[Jeepers]

I also have two Hyperion G3 packs (4s 3300mah) that are very close to the same size that I used in my Nue 1515 1y powered UL1.

this is what I would run If I had them!

[Jeepers]

Jeepers,
I will mount my motor about the same location you mounted yours in picture. Thet way I can use the side locations like yours or up front in front of motor

Even built this way its still a tight fit, the cells hardly fit next to the motor and the sides of the boat. 4s2p does fit on either side of the motor and the hatch does close over 2 4s 5000mah Poly RC packs.

[detox]

LuckyDuc, Have you ran your boat yet. I have been following your build, but it hasn't been active for awhile now. I especially like your idea of using the UL-1 motor mount.

Maybe I will put one lipo pack beside the motor and one pack in front of the motor? Never know until I run hull on water.

[LuckyDuc]

LuckyDuc, Have you ran your boat yet. I have been following your build, but it hasn't been active for awhile now. I especially like your idea of using the UL-1 motor mount.

Maybe I will put one lipo pack beside the motor and one pack in front of the motor? Never know until I run hull on water.

I still have some more work to do on mine, so no water testing yet.... I got too busy with work and life
I plan to get back to it after the holidays

Raydee did quite a bit of testing with his and confirmed that the CG needs to be around 1" behind the sponsons to keep stability at 60+mph speeds. BUT like you said. It is hard to know until you run it.

[detox]

I did mine a little different, Motor right up the front and cells behind, I can get good cog on 4 and 6s setups like this

crabstick,
Thanks for your input. I may try it your way, but one thing that worries me about your motor being so far up front is driveline vibration. It seems that the longer the drive cable the more vibration no mater how much grease I use? Wouldn't a shorter stuffing tube and cable run smoother and vibrate less? Anybody have the answer? What is the best way to prevent a vibration free drive train other than perfect balance?


...

[tylerm]

Hi Detox,

I have sen people put one 4S pack up the front in the nose, motor where Jeepers is, and 1 2S pack under the deck where the fuel tank is, and then another 2S pack on the opposite side.then you have the 2 x 2S packs in series, then parrallel with the other 4S pack in the nose.

Hope this helps,
Ty.

[detox]

Hi Detox,

I have sen people put one 4S pack up the front in the nose, motor where Jeepers is, and 1 2S pack under the deck where the fuel tank is, and then another 2S pack on the opposite side.then you have the 2 x 2S packs in series, then parrallel with the other 4S pack in the nose.

Hope this helps,
Ty.

Wow! That would be alot of lipo capacity

[LuckyDuc]

crabstick,
Thanks for your input. I may try it your way, but one thing that worries me about your motor being so far up front is driveline vibration. It seems that the longer the drive cable the more vibration no mater how much grease I use? Wouldn't a shorter stuffing tube and cable run smoother and vibrate less? Anybody have the answer? What is the best way to prevent a vibration free drive train other than perfect balance?


...

RE: vibration on longer drive cables... Many of the nitro racers mount the motor flat and put an "S" bend in the stuffing tube to reduce flop and harmonics. I have also seen some use additional strut bushings inside the stuffing tube itself and at the motor end.

[sailr]

I'm working on mine now. two 2S Hyperion 5500's up front. They are HEAVY. Still need some nose weight! It will be even worse with my Flighpower 5000's....much lighter. DANG! Boat is built and closed up. too late for weight in the sponsons.

[LuckyDuc]

I'm working on mine now. two 2S Hyperion 5500's up front. They are HEAVY. Still need some nose weight! It will be even worse with my Flighpower 5000's....much lighter. DANG! Boat is built and closed up. too late for weight in the sponsons.

Yep. It is hard to get the forward weight on this hull. You could drill a small hole in the bottom of the sponson tips and add BBs and epoxy. Then seal the hole up.

[highndry]

My batteries are 4" back from the nose..bulkhead is removed, Mine is also lsh power although I'm not sure if that matters

[highndry]

Are you trying to get 4s2p in there?

[detox]

Are you trying to get 4s2p in there?

Yes. For longer run times using the Nue 1515 1y motor. For LSH class I will have to use 4s1p to be legal. How well does your LSH Whiplash run?

[Jeepers]

Raydee did quite a bit of testing with his and confirmed that the CG needs to be around 1" behind the sponsons to keep stability at 60+mph speeds. BUT like you said. It is hard to know until you run it.

And Raydee said his boat has always ran wet I believe.

[Jeepers]

Yep. It is hard to get the forward weight on this hull. You could drill a small hole in the bottom of the sponson tips and add BBs and epoxy. Then seal the hole up.

Dont put the weight forward add the weight on the CG. Directly on it, it works good!

[sailr]

I may have to. I added 3.5 oz. in the front of the tub today and still enough. The other alternative is to move my servo way forward.

Yep. It is hard to get the forward weight on this hull. You could drill a small hole in the bottom of the sponson tips and add BBs and epoxy. Then seal the hole up.

[sailr]

That would require an enormous amount of weight!

Dont put the weight forward add the weight on the CG. Directly on it, it works good!

[Jeepers]

That would require an enormous amount of weight!

not as much as you think!

[Raydee]

My 2 cents is get the cells as far forward as possible. Anything less and the butt end will drag around the pond. My cells are now way up into the nose of the hull with the motor right behind them and it is the best running hydro I have ever owned. It will run wide open all the way around the pond and will turn like it is on rails at 60mph. My Whip was built a little heavy to withstand some abuse so it did run wet at first but once I figured out how to properly load a 1515 1Y on 4s it became a water rocket.

[jesflorida]

My 2 cents is get the cells as far forward as possible. Anything less and the butt end will drag around the pond. My cells are now way up into the nose of the hull with the motor right behind them and it is the best running hydro I have ever owned. It will run wide open all the way around the pond and will turn like it is on rails at 60mph. My Whip was built a little heavy to withstand some abuse so it did run wet at first but once I figured out how to properly load a 1515 1Y on 4s it became a water rocket.

Kit just arrived and build is starting. My basics are Neu 1515 1Y on 4s. What prop are you using to properly load the motor and where did you locate the 2s2p or 4s1p cells?

Thanks for the info:

jesflorida

[Raydee]

This is where my cells are, and the motor is right behind them.

[jesflorida]

This is where my cells are, and the motor is right behind them.

Raydee:
]Thaks for the schematic, very helpful.

Are your G3lipos 3300 mAh or something else?

Can you tell me about your prop?

Thanks again,

jesflorida