6s rigger and only 37mph? help

**crabstick** · 07-06-2009, 12:30 AM

could be anything, more pics and details of your esc motor etc will help us help you..

How are the bearings in the motor? How is the cell balance ? Anything getting hot ? etc

**nate** · 07-06-2009, 12:37 AM

Originally posted by yurkanip

Hello there...you rigger and hydro guys...I am looking for some input. or thoughts. I have a rigger I have been running now for a while, built it last winter, just never had a chance to run it with gps...now I did and am very dissapointed with only 37 mph and on 22.2 volts? doesn't make sense. here are the specs:
34" Rigger, (sponson tip to drive dog), Feigao 11xl on 6s 5000mah zippy lipos. Seaking watercooled esc. Drive line is .187 and turning an x640 detounged. Strut is set a 3/4 inch from stuffing tube to bottom of hull, at 0 degrees...Rudder is perfectly straight.
I ran this all weekend at my brothers cabin and it was fast...but NOW that I have an actual gps to measure...it was 37 mph and doesn't make sense. since the rigger was not running wet, and was full on out for only 3 minutes...this set up should be around 5.5 minutes...give or take. I tried timing at 0 degrees, 3.75 degrees and 7.5 degrees...and all it did was make my motor run hot hot hot..the higher I set my timing.

Any thoughts on setup? I have been running boats now for about 3 years..and have built and setup all of my scratch built riggers...only this one..is not even running in the 50s.... as it should at MINIMUM compared to my other 6s hulls.

shoot some suggestions or questions at me as I welcome them all.
Thank you
Patrick

Yeah Id like to see some pic's too. Wow crazy problem, most 28"-35" boats running over 20volts on the proper setup should see atleast 45mph and up...

**yurkanip** · 07-06-2009, 01:02 AM

Yeah.,..it is a crazy thing..with this rigger. and as you said...all of my 6s hulls would run 50 no problem..even poorly tuned hulls would get close to 50, before I tuned them. THis hull is tuned...it is balanced right at the turn fin. motor has perfect bearings, cells are balanced EVERY charge, (running 2 3s in series) it rides flat and tail doesn't drag or bounce...like I said this thing is balanced..and it still only moves 37mph. pics later...as I don't have my digital camera with me (still on my 4th of july vacation) my feigao 11xl turning the x640 does get very hot...I do not have a temp gun, but it is too hot to touch for sure. this is on 0 timing, 3.75, and 7.5 timing. I am not sure if the esc is going into thermal slow down...right from the get go or what.
The hull is a keps .21 hull. can be found in some old posts on here., when I built this particular boat. here is my original post, before it was finished.

http://forums.offshoreelectrics.com/...ight=6s+rigger

**nate** · 07-06-2009, 01:06 AM

OMG Very clean boat, and it only runs high 30's...ummm cell balance problem maybe.. does your charger peak those at over 23volts full charge??

**yurkanip** · 07-06-2009, 01:17 AM

Nate...Thanks for the compliment...it was a great build...just not happy with the speed.
balancing...I charge the 3s seperately...and run them in seires...this is not a single 6s lipo...just for the information. they are balanced out at about 12.51 each pack. I am NOT using a balance harness. I have the 5.5 bullet connectors, soldered directly to the leads, and basically make a balance connector with the lipo leads...instead of using a y harness etc. so I am getting the 22.2 voltage.

**crabstick** · 07-06-2009, 01:59 AM

if the motor is really hot then its working hard for some reason, no driveline binding?
id try spinning the motor by hand and just see if the bearings are notchy or noisy. Have u got enough free length in the flex cable to allow for wind up ? From the pic it looks like you are running a thrust bearing, How are the surfaces the balls run on ?

Have you checked the balance per cell? You could run it for 1min and then pull it in and plug a cell meter in and get voltage per cell

one other thing I would check is solder joints on the motor wires and batt wires where they solder to ESC and bullets, if you are still no closer open up the motor and take a squiz

**yurkanip** · 07-06-2009, 02:35 AM

Thanks...
the flex shaft has 1/4 inch between drive dog and strut. Flex turns like butter...smooth and greased every run. have not checked individual cells after runs. All of my solder joints are clean and solid....one thing I thought about, as you mentioned wiring....come to think..when I soldered bullets onto the lipos...I simply used male, and female combinations to make a y harness...using the actual wires for the lipos. positive to potive on esc, negative to negative on esc..and the other positive/negative connect together....however...thought of when I soldered the bullets...I did not cut the jumper wire (negative to positive) to be the same length as the other positive and negative wires. ......this just popped into my head...but still stumped that different length wires would give different voltages on identical packs... thoughts?

**crabstick** · 07-06-2009, 02:54 AM

on the wire length, its possible it could be it, by adding length its adding resistance, what size wire ? no broken strands? does the wire heat up at all?

Are you charging with balance plugs ? IMO its the best way to charge lipos, get a cell meter that plugs into them. they are about 6$ at hobbyking and the best thing to test lipos for the price.

the thing is the motor is getting hot so i would prolly look at that also have u got another you can swap it out for?, assuming your low voltage cutoff was set correctly if there was a cell damaged it would be hitting that, is it a hard or soft cut?. Its not something as silly as throttle EPA or trim (sorry not telling you how to suck eggs just asking if you have checked)

**Simon.O.** · 07-06-2009, 03:22 AM

Most of the electrical componentry checks have been detailed. You know better than me if your gear is in order.
Here are my two suspects.
Motor
Coupler.

Now the second is a problem that I have had before and that is a slight shaft slip at full power although this usually gets a lot worse after about 10-20 seconds and becomes apparent very quickly. This is with my home made wire couplers.

The first issue ( the motor) may be easy to diagnose.
Assuming that all else is left as in the hull, do you have another motor that you can drop in a give a run. The heat that you mention is a concern. I do not have a temp gun either but the old 5 second test is good enough for me.
If it is too hot to touch for 5 then the setup is too hot and the motor may now be damaged.

I will follow this thread and see how it all pans out.

**Apples1** · 07-06-2009, 04:04 AM

Maybe the GPS is rooted? May be those cells arent right, i have had cells that show full charge but under load drop down to bugger all, another thing you said you were into boats for a while now, Put and known Quantity On the water ( IE and BJ26 or SV27) and get a speed comparrison against it, it sounds strange that you were happy with the speeds untill your GPS showed 37MPH? Something sounds fishy!

**Fluid** · 07-06-2009, 05:19 AM

Your CG is too far back and you're dragging the transom. Angle the strut down ~3 degrees at the prop end and try it - set the boat on a flat table and check it, don't eyeball it! A lifting prop may help too but if you have no rigger experience then stick to X or M props. That x640 should get you deep into the 50s with decent packs. I don't think that the Zippys are very good at the high amp draws you are experiencing.

You may have problems with the motor etc. as well, but get that transom out of the water first.

You do not need to charge through the balance taps, I never do. I balance the packs before charging and check them afterwards. I seldom have to spend more than a few seconds....

.

**ozzie-crawl** · 07-06-2009, 05:36 AM

also check your esc, have heard reports on some of the seaking/turnigy escs that if your low cut off voltage is set to 3v it will limit the esc to half power for some reason. needs to be set for no cut off, if you try this just be carful you dont run for to long

**yurkanip** · 07-06-2009, 11:58 AM

Thanks for your replies members. One thing I have not checked is the spinning of the coupler....that could be a weak point in my setup. I do not have a flat spot ground on the motor shaft. the coupler is octura...and I crank that thing tight tight tight. thrust bearing is free spinning and rides on a smooth surface. flex is not binding..I have ruled that out, before I decided to post this problem on the forum. I was happy with the speed, but as EVERY setup they can always be inproved..which is what I was looking for...only now I have gps to back it up completely and want to improve the speed. Not sure how that sounds fishy, Apples1. all of my 6s hulls have run starting into the 50s, untuned and even running wet. so I am trying to pinpoint the cause...and also the heat issue with the feigao 11xl. I have a 10xl I will try. the seaking...is a new esc. But you have an interesting point in saying that seakings will cut half power...when cell cutoff is set at 3v. I have mine at 3.2 and it feels half power..and not to mention it cuts at 3 minutes. soft cut, or slow down.
one thing I have added since the pics show in my original build is a rear ski, under the hull....it is setup very clean. That helped the boat keep the rear end up during a half throttle turn....but really did not make a difference in speed turns...so I know the rear is not dragging. As others suggested...I stated earlier, that my cog is right at the turn fin...so if anything..the weight is too far forward, rather than too far back. the hull is pretty long, so I have a good amount of adjustments with lipos inside.
back to some other ideas.....the wire length on my lipos ARE different lengths...once I finished soldering them...to make the original wires a series connection...they are not all matched....never thought it would matter..but I am really debating that now...or cutting them all short/the same length then resoldering the bullets back on. so every wire length...connected is the same.

I will try to get pics of the rear end when I get home from my trip....
it might be possible that this motor is on its final run...being that I have had it pretty hot..... anyone else use Feigao and have major heat issues?

one more thing...I checked my gps on the drive home..and it matched my cars speed, so I know it is not that.

Thanks again...keep em coming if you have any thoughts.

**Gerwin Brommer** · 07-06-2009, 12:41 PM

flexshaft-propshaft : slip ?

6s rigger and only 37mph? help

6s rigger and only 37mph? help

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