Tertiary Testing

[Fluid]

Today I took the UL-1 out for the third time, now with the large prop. The stock prop has worked well with good speed and handling, but I wanted to try the Graupner K45 to see how it effected handling and speed. Knowing it would give higher speeds than the stock prop I lowered the strut to 1" with about 1 degree of down angle at the prop end. The two 2S/5000mAh TP packs put the CG 2.7" behind the sponsons; I heated them up to ~90F before running the boat.

The hydro had no problem getting on plane with the 'heavy' packs, I simply gave it full throttle and up it jumped. (Trying to ease into the throttle just makes the model submerge.) The K45 really yanked it out of the hole and top speed was attained quickly. I was running on 3/4" chop but the boat was stable as it skipped across the waves at full tilt. No GPS but it appeared to be in the low/mid-40s on rough water. The larger prop did seen to widen the turning radius a few feet versus the stock prop.

I thoroughly enjoyed the 2-3 minutes I ran the model, and the temperatures afterwards were around 100F on the motor, ESC and cells. I just wish I had a larger pond to run on with fewer obstacles. BTW I had complete control up to 400 feet away, the furthest I could test on the water.

You'll notice I've modded the appearance of the model a bit, although nothing that would effect its performance. The more I run the UL-1 the more I like it. Next weekend is it's first race and on bigger water - I can't wait!





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[Ub Hauled]

Good to hear Jay, any video?
Why did you use the K45 instead of a M445?
Also, were you using the usual Spektrum radio sys?

[Steven Vaccaro]

Looks nice all painted the same color.

[JimClark]

Looks good without the uprights Jay
On the real UL's the only reasion the uprights
were used was to provide more space for the sponsor names.

Jim

[JimClark]

Delete double post

[Doby]

Hey Jim;

He heard you the first time

[JimClark]

What the heck is up with the double post's. Sure wish I could delete my own posts

Jim

[Fluid]

Why did you use the K45 instead of a M445? Also, were you using the usual Spektrum radio sys?

No video - you'll have to wait until next weekend. The local club is specing the prop on our LSH and LSO boats to keep the performance level closer together. Other clubs have found that the racers who are good at tweeking a prop have an advantage in the BL spec classes. We want to use inexpensive props with good performance but limited tweeking ability....hence the K45. We need to do more testing prior to making a decision, but so far I like it.

I kept the factory radio in the boat, it works great and I don't have to drill a hole for an antenna. I may or may not change it out later.


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[properchopper]

Jay, Are the strut height measurements you're giving from the bottom of the hull to the bottom of the strut or to the propshaft centerline ?