P-Limited race speeds?

[zooma]

I did not want to hijack the P-Lim motor thread. My club has a twice monthly race program. But none of us race outside the club, so we don't know how fast the serious race boats can go. On the other hand, we are not burning up motors or ESCs, just having fun. We keep the monos and cats separate. My Impulse31 is a typical club mono: AQ2030 motor, 80 amp ESC, S/B M445 prop, 2x2S packs, sanded bottom, 30% CG, and is competitive in our group. Speed tops out at 37MPH (Garmin Forerunner 201), which I thought was respectable. Over on the motor thread, I hear people talking about speeds in the 40-50 MPH range. So I can imagine that the motors get cooked. I once cooked one right away just by bumping up the timing.

So, what is a realistic competitive speed, and current draw in P-Lim, and how do you tune for it?

Thanks

[Doby]

If you guys are not burning anything up and having FUN...then don't change a thing!!!

There was a thread somewhere that dealt with everything you ever wanted to know about tuning p-limited boats....I'll see if I can track it down.

[Doby]

http://forums.offshoreelectrics.com/...ht=#post599851

Have a read through this.

[dethow]

Agreed with Doby that's you're all good if not burning anything up.
The only additional question I'd have is your discharge rate on the batteries. Everything else you noted sounds like you should be in the 43 to 45 mph range at a minimum.

[Darin Jordan]

I only really have focused on gathering speed data in one class, my favorite, P-LTD OPC Tunnel.

In terms of lap times, the only real way to equate performance, I average around 1:35.xx to complete 6 laps on an official 1/6th mile NAMBA course.

If pushed, I run closer to 1:31.

I hold the current office heat racing record at 1:28.xx.

All using a Castle ICE100 in front of a standard AQ2030, using an ABC 42x55 with a few tweaks.

Average amp draw is around 89 amps, based on the ICE data recording.

Hope this helps.

I'm not sure this kind of lapping is typical in this class, however. Not sure why.

[Doby]

You asked about speeds...my Motley Crew has been GPS'd at 49.5mph (for whatever a GPS speed reading is worth) in oval trim with the stock 1800 motor and a HK 80 amp ESC running a Turnigy 5800 mah pack. Its set up to run very loose to get that speed. Does it always run that speed during a race...sometimes in the straights with the wind...but otherwise no.

Ditto my stock Revolt.....solid 46 Mph in race trim.

[Shooter]

49.5mph. Are you claiming fastest Motley Crew with that?

[Doby]

49.5mph. Are you claiming fastest Motley Crew with that?

I think its pretty much the fastest MC on the planet....but then, I'm biased.

[raptor347]

The only boat I have speeds for is my rigger. Through the traps at Legg at 63mph in rough water. AQ 2030 and an ABC 1817.

[rayzerdesigns]

I have seen page with one of your riggers..yikes it's fast..guess I need to get u to build me one..

[rayzerdesigns]

And doby..I might have to challenge u with that..lol..but with my measly 1500..

[Doby]

And doby..I might have to challenge u with that..lol..but with my measly 1500..

1500 Mph...you got me beat!

[zooma]

http://forums.offshoreelectrics.com/...ht=#post599851

Have a read through this.

Thanks. Last year I read, printed and highlighted the David Newland thread. Now, of course, sometimes in the excitement I get things mixed up. There is also a good tuning guide from RCchief on his web site.

[zooma]

Agreed with Doby that's you're all good if not burning anything up.
The only additional question I'd have is your discharge rate on the batteries. Everything else you noted sounds like you should be in the 43 to 45 mph range at a minimum.

Thanks. Yeah, I thought my equipment and setup were in the ball park. Don't know about current draw. I might put my Swordfish data logging ESC on it to get a reading. I am starting to wonder about the GPS readings. Our practice lake is small and we go around in a continuous circle. That might be affecting the accuracy, or even limiting the boat's top speed. We will be racing on Saturday at the big lake with a NAMBA-like course, so I will leave the GPS in the boat.

[zooma]

Here is a specific question. Is the Octura M445 the prop of choice for P-Lim mono with the AQ2030 motor? If not, what are the hotter alternatives?