First Run w/38x63

[Drag Boat Bob]

GPS location pic

I ended up with it as far forward as I could get it, but still in the back of the boat.

Here is where it ended up.

[Brushless55]

Awesome, that's where I run mine..

[6S HYDRO]

Just got mine tonight, and ran it 41.1 mph on 4s and 46.0 mph on 5s but i did not have nearly enough lake. That was on the stock plastic. I picked up a 38/63 for this boat and i will run it tomarrow.

[Drag Boat Bob]

Just got mine tonight, and ran it 41.1 mph on 4s and 46.0 mph on 5s but i did not have nearly enough lake. That was on the stock plastic. I picked up a 38/63 for this boat and i will run it tomarrow.

Be careful if you decide to run 5s... many have ended up with molten electronics.

[6S HYDRO]

Oh believe me i know to be careful... Only saw type runs. Came back cool after the 2 passes

[6S HYDRO]

Hey bob, what about your strut angle w/ that prop? Neutral

[Drag Boat Bob]

Hey bob, what about your strut angle w/ that prop? Neutral

My strut is about 1 degree negative.
Rudder is about 1-2 degrees positive.

I think that the L38x63 is designed for a flat 0 strut, but for what ever reason, this seems to be working well for me.

[Brushless55]

what whould you say is the best overal prop you have used sofar?
also what prop has given you the best top speed?

Thanks

[Drag Boat Bob]

what whould you say is the best overal prop you have used sofar?
also what prop has given you the best top speed?

Thanks

I'm not sure if this question was directed at me, but here is what I have experienced so far with my stock setup...

Favorite prop: L38x63 .. best speed with this prop is 50.2mph.

I love the acceleration without noticeable cavitation. Great out of the turns, as I am not an experienced driver and sometimes turn too sharp and shed speed. I will admit that the boat was not turning to my expectation and I moved to the top hole on the servo arm.

Best speed overall: L42x66 = 52.3mph. I have only tested this prop a few times and speed was slowing each time (as with the other larger props). I found that my nicely tie-wrapped motor leads were melting the insulation together. The other temps were not out of spec however. I have now changed to the 5.5 bullet connectors, so we will see...

Lubrication tests will begin on Tue 8/18 and I will use only the L38x63.

After that its hammer time...

[Brushless55]

yes I was asking you..
Thank you for your info, just what I wanted!
I'll have to order a 38x63

I have tried Amsoil grease on my boats, and to me I like it better than the speed grease

[amishjeb]

So Drag Boat Bob, do you recommend using a two-blade? If so which gives better acceleration and speed ratio? I am thinking of changing to a two blade prop for reasons that is "more efficient" and provides less "drag" from reading sailing articles. As one lets off the throttle on a three blade prop, the water current forces against the blades with no escape. At least with a two blade, there is the chance that the water flows through and meets smaller resistance that the three blade prop.

[Drag Boat Bob]

So Drag Boat Bob, do you recommend using a two-blade? If so which gives better acceleration and speed ratio? I am thinking of changing to a two blade prop for reasons that is "more efficient" and provides less "drag" from reading sailing articles. As one lets off the throttle on a three blade prop, the water current forces against the blades with no escape. At least with a two blade, there is the chance that the water flows through and meets smaller resistance that the three blade prop.

The debate of 2 blade vs. 3 blade is one of popular opinion and factual results. Each has its positive and negative attributes. I can only comment on my personal results.

My all time favorite prop (for the UL-1) is the Grim L38x63 (S&B). It is not the fastest in top speed that I have tried, but hooks up real well. This helps me when I turn too sharply and shed a bunch of speed. It also doesn't make the boat go spastic.

I have tried the L40x57-3 which went just as fast as the L38x63, but did not accelerate as well.

The L42x66 was faster, but the boat was not as controlled (seemed to increase the spastic factor). It also made the components run hotter (but not out of spec).

As always when trying larger props, make short initial runs and watch your temps

In my opinion, there are 2 things to watch out for on the UL-1:
1. The capacitor on the esc. It is not sufficient for larger props on extended runs.
2. The motor leads may need to be replaced to larger bullet connectors.

If you find the temps getting high you may want to do what I did here:

http://www.rcgroups.com/forums/showpost.php?p=12281523&postcount=487

http://www.rcgroups.com/forums/showpost.php?p=12282500&postcount=490

Bob

[amishjeb]

Hot Caps

I am going to give that a try today in boring out the fittings on the motor jacket. I wonder if it was intended as sort of a "low pressure" value to keep some of the water in the jacket.

L38x63 sounds definitely like a winner prop!!

I don't know if that capcitor overheating is an "overvoltage" issue. However, I read some posts that involve UL-1 users running close to 20Vdc on the ESC. Using more voltage is never good because along with current is resistance. Resistance is the number one producer of electrical heat.

I will be sure to watch the ESC and the "hot cap" issue when I order the L38x63.

Thanks Bob!

[6S HYDRO]

cant get my 38/63 to hook-up at all anymore, it hit something and i straighten'd it ou and re balanced and sharpened, now nothing

[Drag Boat Bob]

cant get my 38/63 to hook-up at all anymore, it hit something and i straighten'd it ou and re balanced and sharpened, now nothing

I had that happen to my x640. It looked smaller after I re-sharpened it. Never was as good after that.