6S LiPo Hydro prop suggestions

[BulletMaster]

Hey guys...

I have a B-hydro that I have converted to E-Power, using a 6S5000 TP-X pack, Neu 1521/1.5D/S motor. So far have tried 645 and 1440 props... any other suggestions?

Currents are about 120A so far.. I have attached an Eagltree data file for viewing if you are interested?

 

[AlanN]

Yeah,

Drop 2 to 3 S and run a x642.

What kind of speed are you getting? That setup is pretty dang hot for a 6S.

 

[PropNut]

So you have an 1860KV motor in a Q-Hydro. Sounds like your amp draw is correct for that setup with a X645. Prop down to a X642, it will free up some rpm's and lower your amp draw. Also, the three blade V937 and larger V9.. series props work very well on riggers in that class.

Dropping to 4S would lighten the load, but it sounds like the you have need for speed!

All the best,

Ray

 

[jayt]

That is too much motor for 6S for anything but a SAW application IMO - it will be tough to keep the amp draw under control for your LiPos. If your pack is 6S1P then you are likely over-amping your cells and will damage them soon if you are not careful. You did not say if this is a rigger or full-bodied hydroplane, or if you want top speed without run time (SAW) or run time with lower top speed (oval). Obviously a rigger can take a more aggressive prop, but a v900 series prop is a ticket for a new pack if you run for more than about ten seconds at a time. I assume you have a voltage cutoff device or ESC in your boat to prevent cell damage?

Depending on the hull and use I would drop down to an x440 and see how the boat runs. With that setup you need to keep the rpm up to maintain the desired lower amperage draw. A free-running boat will draw a lot less amperage than a wet running boat and this effects motor and prop choice too....

I find it hard to believe that the 1440 and x645 had similar amp draws - there was no data file attached to view.

.

 

[BulletMaster]

http://rapidshare.com/files/23138397/EB_Hy...1440_80AESC.FDR

Ok,

The hull is an outrigger hydro that I was using a MAC45 in. See photo ( http://i169.photobucket.com/albums/u238/su...s/group_001.jpg ).

Looking to race this in Oval heat racing. ESC will be Barracuda 180. Data was taken using a HV 80A ESC (quite surprised it held up as long as it did).

As I am using datalogging, heat is not that big of an issue as I am creeping up on run-time... Hopefully I will receive some props and the ESC tomorrow. I have a week before I am due to leave for an O/S racing trip. That's a week full of testing as I am off work.

I don't have the data for the 645 prop... But will get a set. The hull needs a little trimming yet... still doing some hopping in the straights. Spent a fair amount of the logged run off WOT... but was quite pleased so far. Estimate speed around the 60 MPH area. I do have a radar gun, so should be able to get some accurate speeds later in the testing. I also have the RPM module for the Eagletree micro... so can get RPM values too.

Using 3/16 flex shaft too.

appreciate the advice guys...

 

[Andrewg]

Jay

we are finding with Thunder Power Extreme 5000 25C the packs are fine running a 1521/1.5D in a rigger (34").

In the rigger the packs run 100-120 amps with an H5. This is within the constant rating of the pack and at those discharge levels the cells show no sign of electrical or heat distress. After 6.5-7 laps of 300metre nitro oval - maybe 55C at midsumer. I do the same in 10S scale hydro witha 2215/1.5Y same story no fuss no muss. Total amp draw 2700mah. On the scale that should drop significantly when I either get the right prop or go back a wind so I can use a larger diameter prop ie 57-60mm.

 

[BulletMaster]

I have these props on their way to me...

Octura V940/3 - 1.57" x 2.983"

Octura 1745/3 - 1.77" x 3.009"

Octura 1742/3 - 1.65" x 2.805"

Octura 1.8 - 1.8" x 3.240"

Hopefully something suitable there.

Also have a 646 to try.

Can get a 642 to try as well.

X645 is 1.77" x 2.832"

X642 is 1.65" x 2.640"

 

[Jim Caldwell]

I have these props on their way to me...
Octura V940/3 - 1.57" x 2.983"

Octura 1745/3 - 1.77" x 3.009"

Octura 1742/3 - 1.65" x 2.805"

Octura 1.8 - 1.8" x 3.240"

Hopefully something suitable there.

Also have a 646 to try.

Can get a 642 to try as well.

X645 is 1.77" x 2.832"

X642 is 1.65" x 2.640"

Looking at the data it appears ;

1. the batterys are caving in, the voltage is down to 3.2 per cell, that is where we set the cut off. Too many amps.

You will kill the cells very quickly at this rate.

2. You have a delta wind (low tq.-high rpm) this won't like a 3 blade prop! for ovals. suggest you try a detounged x438 to start to get rid of the hopping and lower the amps and raise the rpm.

3. if you want, email me the data file and I will load it into my Eagletree and try to give you more detail.

[email protected]

 

[AlanN]

Andrew,

This from the guy so worried about us running 2P? Is this how you are directing your mates?

There is no reason why you could not go 60mph on a 4s with that motor. I've seen Brian B do it with general ease.

You guys are killing motors and speedos for no good reason.

Heck I was running in the 50mph range with my sport hydro on 12 cells with the same motor.

I don't get the "run time" statement made above. The only reason you may not be getting run time....your pulling too many amps.

 

[photohoward1]

Jay
we are finding with Thunder Power Extreme 5000 25C the packs are fine running a 1521/1.5D in a rigger (34").

In the rigger the packs run 100-120 amps with an H5. This is within the constant rating of the pack and at those discharge levels the cells show no sign of electrical or heat distress. After 6.5-7 laps of 300metre nitro oval - maybe 55C at midsumer. I do the same in 10S scale hydro witha 2215/1.5Y same story no fuss no muss. Total amp draw 2700mah. On the scale that should drop significantly when I either get the right prop or go back a wind so I can use a larger diameter prop ie 57-60mm.

PROP DOWN!!!!! Listen to them. 55c is not acceptable in mid summer. Keep your amp draw to about 100 and you will

see a bit above ambiant on the equipment.

Andrew you are way off on this one. He will never make a heat race pulling 120 amps and 5000 cells....

In a 1 minute race he may be OK he will pull about 2000mah out of the packs but our goals are running 1 mile +

not just 45 seconds to 1 minute. A boat needs to be able to go for 2.5 to 3 minutes. This includes 1 lap befor the start, 6 laps of heat racing and 1 cool down lap. In the states he will suck those cells dry....

Howard

 

[BulletMaster]

Guys...

Boat weight ready to run is 3.9Kg's (Porky I know...but its a converted Nitro boat).

I will try going to the smaller props as well, and see what's what.

That's one thing I really love about the datalogging... you can see changes instantly and they are quantifiable. Along with Radar measurement... you can have it all.

Also no need to run round and round... short dashes tell you everything you need.

What about other suggestions re-motor?

 

[Andrewg]

Tony said it all data logging and quantifiable

All the comments excepts Jim's were mere opinion (Jim most likely because the charge was a several+ days old)

As for opinion it is wrong - and we have been running monos riggers and sport hydros all summer. The fact is the cells we use and motors do it with ease without any heat issues or performance deterioation, and where did runtime come from I have yet to use more than 55% of capacity in a race.

 

[AlanN]

I would run closer to a 1200-1300 Kv motor. Same or larger than the 1521. And I would still stick with a prop close to 42 mm dia for starters.

Tony,

The higher the voltage you use the less amps you should have to draw. I understand that your running a fairly heavy hull. But you should be closer to 80mph pulling 120 amps than 60mph.

 

[BulletMaster]

well,

race meeting is over.

I ended up going to the 1521/1Y motor with a H5 prop. Ran reasonable consistent runs all weekend. Temps were fine (motor was only reaching about 30 degrees C). Batts were taking back 2700 - 3000 mAHr after a heat.

Time to build a new lighter boat. If I can lose about 1 Kg then should run a lot faster....

But as a proof of concept...in my opinion it worked.

 

[Jim Caldwell]

Sounds like a great combo!

How were the amps and RPM's?

Hopping gone?

 

[BulletMaster]

Jim,

new boat under construction as we speak....

should be a beauty...

the old boat - yep, eliminated the hopping and it went well. Just needed more speed...

 

[BulletMaster]

Here's the new boat....

2.5 Kg with ESC, shaft, prop,turn fin, radio and cowl to fit.

what do you guys think?

 

[ozzy2]

Hy Tony

Iv seen that somwear befor!!!!!!!

 

[BulletMaster]

what do you think of it Paul?

um.... new boat, not sure what you mean?

 

[raptor347]

Good looking boat. What are the dimensions?