ALUMINUM prop......WOW!

[Shooter]

Well, I thought I'd try it for kicks. Run to run comparison resulted in favor of the Aluminum prop. I realize there are all sorts of variables (prop balance, sharpening, conditions, etc....), but the AL prop resulted in slightly higher MPH on the GPS. I took a pass with the Beryllium, swapped props, and took another pass with the Aluminum. So if anything, it didn't degrade the performance!

It makes sense that it would spin a little faster with less rotating mass (old car buffs used to reduce rotating mass under the hood.......crank, con-rods, etc...).

They sure are cool looking if anything. Our lake is extremely clean, so I don't have to worry about too many floaters that might cause damage.

I'm running a stock UL-1 with an AL X440 prop. So far, it's topped out at 43mph. If I could just get rid of the sponson dance, I could steel some more speed.

[Ub Hauled]

Have you seen the CNC props from CMDI?
Sharp as a razor and really light... good stuff.

[Drag Boat Bob]

Well, I thought I'd try it for kicks. Run to run comparison resulted in favor of the Aluminum prop. I realize there are all sorts of variables (prop balance, sharpening, conditions, etc....), but the AL prop resulted in slightly higher MPH on the GPS. I took a pass with the Beryllium, swapped props, and took another pass with the Aluminum. So if anything, it didn't degrade the performance!

It makes sense that it would spin a little faster with less rotating mass (old car buffs used to reduce rotating mass under the hood.......crank, con-rods, etc...).

They sure are cool looking if anything. Our lake is extremely clean, so I don't have to worry about too many floaters that might cause damage.

I'm running a stock UL-1 with an AL X440 prop. So far, it's topped out at 43mph. If I could just get rid of the sponson dance, I could steel some more speed.

What other props have you tried? Any 2-blades?

The x440 3 blade is very close to the load of a L40x57/3 and there are some who are reaching 50+mph with that prop.

In a previous post you said you were using the Hyperion 6500's. Is that what produced 43 mph?

Also, what is your setup: Strut, rudder, etc.

I ask, because I think you can go faster than 43mph with 6500 mAh batteries.

[eboat]

I wonder if the lipos were warmer for the second run vs the first run
You should try the two props again in the reverse order and see if you get the same results

On my hydro I have some weight added to help keep the front down and you can really tell when the lipos warm up it starts to lift because it is going faster (with the warm lipos)

Just a thought

[Shooter]

I'll have to check out CMDI.

D-Bob,
I agree. I was hoping for more speed with the batts that I bought. We will be at the lake again this weekend for more testing and I'm hoping for calmer waters. I really think that has a lot to do with the lower speeds. I'm running about 7/8" strut depth (bottom of hull to center line of prop) w/3° downward angle. The sponsons are dancing like mad. Thanks.

[Shooter]

No doubt I need to run more testing to increase the confidence in my findings. Good point about the lipo temp. The best test would probably be alternating props for at least 5+ runs each.

[Ub Hauled]

The bouncing around of the sponsons is inherent to the hull, most guy have/had that going on, each has a different cure.
The UL in racing trim I have seen people being successful with 642 or 445 even, all temps in check.
The 440 is a great prop for a day to day scenario, longer run times and less stress on the equipment.
To make sure that all variables are the same (except the prop) pre heat the lipos to the same temps to each different props and keep all the rest exactly the same.

[Drag Boat Bob]

I'll have to check out CMDI.

D-Bob,
I agree. I was hoping for more speed with the batts that I bought. We will be at the lake again this weekend for more testing and I'm hoping for calmer waters. I really think that has a lot to do with the lower speeds. I'm running about 7/8" strut depth (bottom of hull to center line of prop) w/3° downward angle. The sponsons are dancing like mad. Thanks.

Measure the strut depth with boat on tabletop with prop over the end (pic). The distance from tabletop to bottom of the boat is strut depth. This is just so we are on the same page.

3 degree downward angle? Is this a positive or negative angle (see pic).

I moved my batteries perpendicular to the boat (cross wise) and it helped when it got too loose. Not sure if yours will fit that way, but if so try it. It moves the CG forward a bit.

Also, if it remains too loose, drop the strut to 1" and see if that helps. It did me...

[Rumdog]

I'd suggest flattening out the strut. You may be getting too much lift in the rear.

[6S HYDRO]

Delta Force 26 = Funnest boat i've ever driven!

ME TOO!

[Shooter]

Thanks guys. Just for reference, I DID try lowering the strut a little (OK, more like a LOT) and her rear end got as squirly as a hound dog in a flea market!! ....and then of course the usual....turn into a kite and land like a rock.

Sppplaaaaash!!!

Back to some earlier questions. Drag boat - Yes, I've tried the X440, 2 blade prop.

I'm going to get some measurements tonight (flat on the table method) and see where I stand. I'll also flatten out the angle for the next run. I had a huge amount of downward angle (prop wash angled down into the water).

So far, I love this boat. Speeds are incredible. It's not nearly as stable as my Vegas yet, but I'm sure it will get there. Just need to sharpen my pencil a bit.

Once I get this thing dialed in, I'll repeat the Aluminum vs. Beryillium test.

[mickvk]

Thanks Shooter, I look forward to hearing your results - could you also note water conditions? I'm wondering if there are any setup recommendations for different conditions or if there's a general setting that's best for all. I'm a little new at this. Thanks.

[Shooter]

Unbelieveable! Apparently I had two problems. After close inspection, the clasp on the rudder pushed it's way downward (off the ball joint). I have no doubt this is why the rear end has been doing a little dance.

Geez... All these adjustments and I had this extra variable in there affecting my results!! Argghh!! No wonder why she can't sit straight.

I also found some pretty significant cracks in the hull. I pushed on them and my finger went right through!! Yipes! A little epoxy should do the trick. Probably due to all those flips, roles, aerobatics, etc...

She's all ready to go again. Hopefully tomorrow night I'll get a few runs in. Just have to convince the wife why I need to spend an hour at the lake playing with my toy boat

I'll get back to the AL prop comparison as soon as I get this thing dialed in. Did I mention I lost the AL prop? Yup, it's spending some QUALITY alone time at the bottom of the lake. Well, that's not exactly true. It has some friends down there. The drive dog ($7), the flex shaft ($18), and the prop nut. Hopefully they're having a good time. (2) more AL props are on order.

I'm currently set-up @ 1" strut depth (table top method....bottom of hull to bottom of strut) and 0° angle. X440/3 Beryillium.

[Drag Boat Bob]

Also keep an eye on the little 'allen set screw' on the forward side of the rudder just above the lower arm of the rudder bracket. It WILL come loose without thread lock or similar.

[6S HYDRO]

the AL props dont bend easy?