Ran My UL-1 Today...

[detox]

Using my heavy Maxamps 8000mah packs (these packs barely fit and measure 145mm x 45mm wide x 35mm high) and detunged Octura 645 the UL-1 boat was incredably fast. Do not know for sure how fast, but nearly twice as fast as using the stock prop and smaller 4900 mah batteries. I did have one problem after running the boat for about 10laps... the UL-1 shut down. Im thinking the 645 prop is too large causing the ESC go into overload protection. I was also using a lot of on and off throttle which I know will cause overheating. After about 10 minutes of cooling off the ESC operated like normal again.

Even with the heavy batteries the boat ran a little loose on sponsons and did chime walk some, but this can be fixed maybe with deeper prop depth, prop angle, and COG. I did not use air dam...the extra weight of these large batteries kept boat from going airborn.

Here's a couple of mods I did to the boat afterwards. During run I noticed very little water coming from water outlet, so I installed a home made 3/16' aluminum motor cooling coil. Also check out the upward angled 1/8" aluminum water outlet...water exit should be easier to see now. I also noticed that turn fin area is OK and has not cracked so far.

[egneg]

I am curious as to the speed with the stock prop as I have never used it. The one that came w/my boat left a lot to be desired.

[properchopper]

The specs state that the SC thermals at 230 deg F. Pretty hot; also the LVC kicks in at 11.6 V. Doubtful that with your big packs the LVC kicked in, and 230 deg is hotter than I've ever experienced. I'd suggest checking the solder joints on the motor/SC junction.
My UL-1 powered LSO mono would stop & start; it had de-soldered one connector under the shrink and became intermittant. I redid both the UL-1 & mono with 5.5's I need to run the mono for 4 minute LSO heats so I put in an Etti cap board to keep things stabilized & will test tomorrow.
Frankly, at this point I'm questioning the accuracy of that 11.6 LVC. I hope I'm wrong !

[detox]

I checked voltage of the large packs and they were OK...15 volts total. I am sure the extra weight and large prop caused this thermal overload. Or maybe it was a failed soldered joint. THANKS

I remember I did have to resolder my SV27 ESC/MOTOR connectors. I now use Castle bullets without a problem.

[rightturnonly]

I ran my UL-1 with the stock prop today. Ran her right out of the box....GPS'd at 39.2 MPH...

[detox]

I was going to try the CMD Racing 3 Blade CNC Aluminum Prop (45mm diam 69mm pitch), but the drive dog on propeller shaft needed readjusting so that threads would be exposed for prop nut. This prop covered all of threads.

Next I will try the .062 wire drive with Octura m445. Then maybe the CMD aluminum prop?

BTW...I wonder how well thIS big three blade CMD prop will work in the UL-1?

[properchopper]

I immediately replaced the stock shaft with an Octura .150; less windup & I gave myself more shaft length behind the drive dog. I've watched Jan lose lots of props with wire drive so I'm a little shy of them myself.
I tried a m445 & it was a wild ride !! Way fast ! Once I get the trim dialed I'll try it again. For now I'm using the Grimracer 40X57X3. I have the CMDI 45X69X3 & may try it, 'tho I bet It'll cavitate like hell before it bites. Hopefully tomorrow I'll get some smooth water to see how the G 10 ride pads [DJ's idea] do.
If the sponson wiggle persists, I have what may be the "final"solution in mind, although it involves some scary surgery !

[detox]

I noticed that my sponsons would wiggle at top speed "only" in slightly choppy water (2" chop). I will try more forward COG to see if that helps.

I tried Raptor347's 65 mph prop (he used a modified Octura 2047) in my SV27 powered Rigger Insanity and man is this prop fast. I can see why he ran 65mph using this big prop in the UL-1. Octura makes smaller versions of this 20series prop that I think would work great in this UL-1 boat...although OSE does not stock them.

[Capt. Crash]

That balance thing is what I've been saying about my boat...ran it again yesterday and tried moving the batteries back a little...nope..."hospital hop" have to have all the weight forward . 10 laps may be pushing it for an aggressive prop...depending on what a lap is.

I was curious about those MaxAmp 8000s but I see they are only rated at 20C. That's why I went with the 5250s....30C.

Here is pic from yesterday....RightTurnOnly and me duking it out.....more to come.

Edited to add...I see they have a new 6500 2s 30c pack now....rats!

[detox]

Capt. Crash,
I think you made a verygood battery choice (Maxamps 5200 30c)...you can always add more weight if needed. The new Flightpower 28 and 30 are verygood batteries , but their larger size will barely fit in the UL-1 hull.

I was looking at all the Grimracer lifter style props. I am betting some of these would be worth investing in. They take a little more time to sharpen and balance because they are so beefy.

Cool picture BTW!



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[detox]

I am thinking the sponson hopping or chime walk (loose) at higher speeds is caused by the steep AOA built into sponsons. I will try to cure this hopping by setting strut deeper, using a higher lift prop, and/or more upward angle on propeller strut. This extra lift at stern should decrease AOA of sponsons and decrease the chime walk.

I installed home made cooling coil and rerouted my water cooling lines to try and prevent thermalling using the larger props...(I think it was thermal shutdown?).

[Capt. Crash]

I think you may be right about the chine walk...I have mine set up the way your describing and have eliminated it as long as I keep the battery weight forward too.

Looking at your can cooler I have to wonder if that isn't your heat problem. I use that coil system in a brushed Crackerbox boat and found that it takes a combo of the coils flattened , taped down and thermal pasted against the can, extra tab cooling and a electric end bell fan to keep my motor cool enough to run for a few minutes...and this is with a NiMh 6 pack. Here is a pic of that mess. Maybe you need to go back to a water jacket?

[Darin Jordan]

Maybe you need to go back to a water jacket?

I'd say that's incredibly good advice... Jay turner did an article in RCBM some time ago talking about this... The coils are minimally effective. One of the beauties of running BL motors is that you can put the water in direct contact with the can. INFINATELY better cooling performance...

[detox]

Guys, The boat thermalled using the Aquacraft water jacket, I have not ran the boat since I installed the home made cooling coil. I know the water jacket sounds like a more logical choice, but now I am having second thoughts. I will take temp readings at shaft/bearing area to see which is best...coil vs. water jacket. I do know the coil will allow more water flow...which I think is good for cooling the ESC.

Isn't the ESC usually the first to burn up?

BTW Captain Crash, After I formed the cooling coils on smaller diameter socket. I then wrapping 300grit sand paper around socket then sanded the inner part of coils flat...so simple yet so effective.


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[detox]

I'd say that's incredibly good advice... Jay turner did an article in RCBM some time ago talking about this... The coils are minimally effective. One of the beauties of running BL motors is that you can put the water in direct contact with the can. INFINATELY better cooling performance...

INFINATELY better only if you can controll the flow aroung motor...much like a silicone jacket does. Water can act as an insulator if it is not replaced correctly with cool water.