Next props to try? (Stock ProBoat Mystic 29)

[desmobob]

I'm having a ball with my new Mystic 29. Two of my buddies have them and are running theirs bone stock (not even a strut height change).

I started experimenting by raising my strut and balancing/sharpening/polishing my stock prop (direct copy of Prather 215). My boat was a little faster than theirs. Then I switched to a balanced/sharpened/polished Octura x640. My boat gained a bit more speed advantage. Naturally, I want as much as I can get with my stock power system (1800kv motor and 60A ESC; 4s 5000mah 40C).

I have balanced/sharpened/polished an Octura x642 but it looks so much larger than the props I've used so far, I'm a little leery of it. I'm familiar with the recommended protocol of running the boat wide open for half a minute or so and checking ESC and motor temps (so far, my temps have not been above 93F with the x640). I need to wait for some calm conditions to give it a try.

I was interested in an Octura M-series prop (detongued x), but I can't find one in the size I'd like to try... M640. I found an M445 but it seems like too much additional diameter. I'm tempted to detongue an x640 and x642 but I hate the thought of grinding on beryllium copper. (I do my sharpening work on them in a bucket or sink of soapy water so I don't raise any hazardous dust.)

What are some other props I should experiment with?

Thanks for any tips,
desmobob

[properchopper]

Bob,

The PB 1800 is quite hefty and can handle some rather agressive props but as I'm sure you're aware of, batt consumption and heat rise as load increases. You're on the right track by testing short runs with the temp gun. I'm rigging a P-Ltd raceboat with the "other" 1800 motor & need at least 4.5 min with good speed and longelivity and will report some prop testing results, 'tho not till at least next week . Starting tomorrow I'll be SAW racing with Darin (who had a hand in the Mystic design) and see what he has to say & get back to you. You should likely have no real problems with the 642 or M445 for 2-3 min runs, but keep your setup loose (raising your strut as you mentioned keeps the prop unloaded some and helps), and check your watercooling flow. FWIW my rig has two pickups; rudder & propwash to maximize the cooling flow to the SC & motor separately.

[CHIEFY_44]

I have a miss G which is basically what the mystic is I run a leo 2200kv with a m445 np but as tony said keep a eye on temps, set ur strut bottom level with the sponsons and u should be good to go

[desmobob]

Thanks Tony,

I did get to do some very limited experimenting with the x642 last night. I made a couple of short, wide-open runs on perfectly flat water. I had some serious porpoising on the first run and moved the batteries up a bit... didn't really help.

I couldn't see that the boat was any faster but didn't have a GPS on board to check for sure. Also, the place I ran the boat was weedy, and I never knew for sure if I was trailing a piece of weed or not during my runs. I switched back to my x640 and the boat seemed to run much flatter, as fast or faster, and ran cooler.

When I got home and greased the shaft, the motor collet stripped so I'm out of business for a while. I ordered a new short Octura and I hope it fits... I had already bought the really nice three-piece Aeromarine style collet set from OE, but it's too big in diameter (the thing is huge!) and too long to use in the Mystic. I have another type of stainless steel collet on order from Kintec (the first one on the collet page) and I know it's long, but if the diameter is small enough for it to fit the Mystic, I can always shorten the motor side of the collet.

If I have to, I can relieve a bit of the Mystic's motor mount base to allow for the larger diameter of the new collet.

Take it easy,
desmobob

[properchopper]

DSC02626.JPG

Bob,

Three things : Be very carefull with the weeds. A few years ago Legg always had weeds in the spring and summer. Before I wised up, I smoked several speed controls (all $$ Castles) when weeds wrapped around the prop.

My personal preference is for Octura 2-piece colletts. They seem to have the best grip. To get them tight & released without hassle, put a TINY dab of anti-seize on the threads and taper.

Don't drive yourself crazy trying to eliminate the porpoising. Seems inherent.

[desmobob]

[ATTACH=CONFIG]62240[/ATTACH]

Bob,

Three things : Be very carefull with the weeds. A few years ago Legg always had weeds in the spring and summer. Before I wised up, I smoked several speed controls (all $$ Castles) when weeds wrapped around the prop.

Thanks for the heads up on that... I was already paranoid about the weeds hanging on the rudder and plugging the water intake (I've had that happen on real outboards). The place I was running was not a place I'd normally run, but I was really dying to get out and make at least one run with the new prop. :-)

My personal preference is for Octura 2-piece colletts. They seem to have the best grip. To get them tight & released without hassle, put a TINY dab of anti-seize on the threads and taper.

Glad to hear that as I have one of the Octuras on the way. Thanks for the tip on the anti-seize... I have a jar of it in the shop and will make use of it.

Don't drive yourself crazy trying to eliminate the porpoising. Seems inherent.

It is maddening, isn't it? I have a feeling I've done the best I can do at eliminating it until I get a chance to blueprint the hull (if that even helps....).

Thanks again for your help; I appreciate it.

Take it easy,
desmobob

[CHIEFY_44]

Blue printing the hull does go a long way in stopping the bounce, tony has seen what a difference it made to my mg, right now all we can think of to try is a air dam to take it away all together

[desmobob]

Blue printing the hull does go a long way in stopping the bounce, tony has seen what a difference it made to my mg...

Good... hearing that will motivate me to get it done soon (not that much boating weather left here in northern NY).

Take it easy,
desmobob