UL-1 Power system upgrade arrived!

[detox]

Have you tried the factory detunged Octura m440? I think you will get more speed using it.

Water conditions have more effect in how the UL-1 handles and it's speed. I find it difficult to get the same exact water conditions every test.

[Drag Boat Bob]

Great data...again!

I must admit that I am very surprised that the 38x55 performed poorly. Was the instability accompanied with any increase in speed or was that down also?

Have you given any thought to the m440? I believe it is just a de-tongued x440. Not sure about you, but my fingers are numb for a long time after a lot of filing.

Thanks, and keep the data coming...

[LuckyDuc]

Have you tried the factory detunged Octura m440? I think you will get more speed using it.

Water conditions have more effect in how the UL-1 handles and it's speed. I find it difficult to get the same exact water conditions every test.

I have not. I thought that the m440 was a two blade prop? The x440 is a 3 blade prop. I was hoping to find a 3 blade prop for this motor.

I try to do my testing on similar water conditions, thus keeping that variable as consistant as possible. This is normally 30 minutes before dark when the lake is glass with a slight ripple. I might try a Grim L40x52 3 blade also.

[LuckyDuc]

Great data...again!

I must admit that I am very surprised that the 38x55 performed poorly. Was the instability accompanied with any increase in speed or was that down also?

Have you given any thought to the m440? I believe it is just a de-tongued x440. Not sure about you, but my fingers are numb for a long time after a lot of filing.

Thanks, and keep the data coming...

I was suprised about the L38x55 too. Below is the chart and stats from the best run with it.
I may try a m440. To my knowledge the m440 is a 2 blade prop. My x440 is a 3 blade with tongues.

I hear ya about filing

[Drag Boat Bob]

I got around to testing my Octura x440 3 blade prop with the Medusa.
The best strut depth setting for this prop seemed to be 15/16" below the hull.

In short, it had a much higher average lap speed than the L40x57 prop (43mph avg), but had a 2mph slower top end. Temps, Amps, and Watts were much higher though. As you can see by the increased avg lap speed, it was much more stable on the water than the L40x57.

I may de-tongue the x440 to see if I can squeeze a little more speed out of it.

BTW. The Grim L38x55 was the worst of the 3 props I've tested so far with the Medusa. It was VERY unstable. I tried many different setups, but it didn't help with this prop.

x440 stats/chart below.
Temp A = Motor Temp
Temp B = ESC/Battery Bullet connector temp
TEmp C = Motor lead bullet connector temp.

You are right Duc,
It seems they don't make (or list anyway) a 3 blade in the 'M' series for the 440. Odd, that they make the 'X' in both the 2 and 3 blade.

Your data indicates (to me at least) that the L38x55 does not load the motor like the others (watts and amps much less), which I would expect it to be, with the dia/pitch decrease from the 440 and being a 2 blade. However you are pulling 51 mph. I sure wish you had rpm with that setup...

I guess it is possible that the rpm of the motor is up to spec and looking for more load/torque. It might also be the reason for the instability (torque roll?)

Have you tried the m445?

[LuckyDuc]

m445... Not yet, but I have a feeling that it will be pulling way more amps than I'm comfortable with.

[Drag Boat Bob]

m445... Not yet, but I have a feeling that it will be pulling way more amps than I'm comfortable with.

If you don't test, then how will you know?

If the old AQ motor/esc took it, why not the new setup? A short run may prove to be very enlightening.

[LuckyDuc]

Medusa test with m445

I just tried 3 different runs with the m445 and the Medusa motor. Data below. Water condition was close to glass. The boat blew over each run, even with all 3 of my lipos at the front with lead weight. Definitely too much prop and motor for this boat.

[Brushless55]

m445... Not yet, but I have a feeling that it will be pulling way more amps than I'm comfortable with.

I agree, an M445 on your 2200kv motor could hurt something..

[Drag Boat Bob]

I just tried 3 different runs with the m445 and the Medusa motor. Data below. Water condition was close to glass. The boat blew over each run, even with all 3 of my lipos at the front with lead weight. Definitely too much prop and motor for this boat.

Oops...

I guess that takes care of that!

I'll keep quiet now.

[detox]

The whole purpose of the larger 2200kv motor was to run faster wasn't it. Do not give up...put an air dam under it to reduce fly overs, lower the strut more 1 3/16". Keep trying that m445.
...

[line6]

Ya really don't give up if its just blowing over give it some strut angle. and a air dam like detox is saying.

[LuckyDuc]

I have no intention of giving up. However, I would rather find the "best" prop to heat race with in IMPBA first... before revisiting larger props like the m445 for all out speed runs. The m445 generates more heat than I'm comfortable with for heat racing, and race water is pretty rough, even with an air dam for that prop. IMHO anyway.

The x440/3 seems to be the best so far, as the boat is stable and averages 43mph each lap with a top end of 52mph. The Grim L40x57 is super fast too (54mph), but is pretty aggressive for heat racing as well and less stable. I'm hoping that the Grim L40x52/3 runs similar speeds and stability, but with less amps. When I finish testing props for heat racing, I will then mess around with larger stuff like the m445 and air dams to satisfy everyone's interest in all out speed testing

[LuckyDuc]

Yippee!

Well… I think that I found the right setup for the Medusa and the Grim L40x57. The 73.53mph number is legit as the gps had 8 satellites fixed when it got that reading, but it only did it right off the start. The boat cavitated for the first 10yds, and when it finally hooked up it took off like a rocket. Thus, yielding the 73.53mph reading. After that it settled to a 55-52mph top end each lap. The boat was planted with this setup too. I lowered the strut further than with previous test runs (15/16 inch.) It cavitates a bit off the start, but once it hooks up, it is planted. I also angled the turn fin up a bit too. Color me HAPPY. I like this little Medusa motor and the Grim L40x57 prop.

[detox]

I wonder why it slowed the way it did? Did boat appear to be going slower after that 73mph fast start?