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View Full Version : HPR C5008 185cm prop size dilemma... Any suggestion???



PETERPAN
08-02-2011, 10:01 PM
I just recently bought a HPR C5008 185cm all carbon fiber hull from Switzerland and yes it did cost me an arm and leg but what is a guy without toys???? This bad girl will be powered by 2 Lehner 3060/10 and 2 12S/3P 4000 Lipos. I'm kind of new to RC power boating so I'm having a dilemma on which prop size to use as my "starting point prop". I know every boat has it's own "favorite prop" so I wanted to use my starting point prop as a guide to finding the favorite prop. Ideally I want to go with a 3 blade but I'm totally lost on diameter and pitch. Anyone familiar with big euro cat please help?

Boaterguy
08-03-2011, 03:43 PM
I don't know how well a 3 blade will perform on a twin cat. You could go with 5 Bladers for a scale look, but two blades will be your best bet.
I don't know good dimensions for props, someone will most likely be able to help

ManuelW
08-03-2011, 06:40 PM
Hello Peterpan,

when I read what you write I would not think about props but about getting enough flotation. Imho 12S3P per engine is WAY too much for the boat. Normally a 12S1P 5000mAh 40C Lipo is enough, for longer runtimes maybe a 12S2P 4000mAh Lipo is okay but 12S3P is an overkill.

Best regards,
Manuel

johnson22456
08-18-2011, 02:48 PM
Octura x457 right and left should put you where you want to be as far as speed goes. You could start with a x450 r&l but that's probably not enough prop for a cat that size. You could have a set of x457s cut down to 55mm or so. The only bad thing about twins is your limited by what props are available. Abc has some bigger props with higher pitch you might want to look at also.

ManuelW
08-18-2011, 06:11 PM
maybe most important question is: how fast do you want to go?
LMT 3060/10 on 12S is not a really hot setup in my eyes, still enough power to achieve some serious speeds. And which ESC's do you want to use?

best regards,
manuel

PETERPAN
09-15-2011, 12:53 PM
Thank you Boaterguy!!!

PETERPAN
09-15-2011, 01:01 PM
I apologize for the slow reply. Been very busy with work. I will follow your advice and go with 12S1P or 12S2P lipo. I'm also about to purchase some props from the Prop Shop. Do you have any recommendation on prop size and pitch? THANKS AGAIN!!! Say hello to Hanspeter for me!!!

PETERPAN
09-15-2011, 01:14 PM
Fast as possible... with all the money I already invested into this project my as well go crazy!!!! What is a hot set up to you??? Like I mention before I'm very new to power boating so I'm kinda lost:sad: I see a lot of ppl using scorpion brushless motors. Is that a better choice? I'm planning to use Schulze fut-xxl-40.333WK.

Best Regards,
Peter

PETERPAN
09-15-2011, 01:20 PM
Thank you johnson22456. I will take your advice seriously in consideration. How about 3 blade props? Thanks again!!!!

Best Regards,

Peter

LarrysDrifter
09-15-2011, 02:04 PM
The props Johnson suggested are 3 blade.

PETERPAN
09-15-2011, 02:24 PM
Thanks LarrysDrifter.

6BOOST
09-15-2011, 07:30 PM
Hi Peter,

I am in a similar position to you having just purchased a 67" MHZ Mystic and being relatively new to rc boating (coming from gas cars), I would have liked a HPR but after numerous emails over 2 weeks with no reply I gave up. Anyway the 3060/10 is a 700kv motor, so 12s is only 31000 rpm, which imo is low unless you just want to do some sport boating, it is however far below the capabilities of these motors and the video's you see of guys doing upwards of 165klm are doing 40-50000rpm. another thing to keep in mind is that the lower the voltage, the more the amperage, the higher the voltage the lower the amperage. So those motor's propped up hard might pull 300 or so amps on 12s, and 150 amps with the same load on 24s, much less heat. 60000rpm is too hot for your application, but you get what I mean.

I would be looking at something between 15 and 18s, I have gone with 3s batteries for my LMT3080/7's (similar kv) so that I can step up in 7500rpm steps from 15-18 and 18-21 for saw purposes. This will bring your heat down and your speed up and put less strain on the esc's, if you were on 18s with 46000rpm and 9000 watts of power draw your only looking at 135 amps, this brings your battery requirements down to 5000mah 1p 45c, you could even get away with less for short run times, but 5000 would give you decent run times, similar to running 5000 2p 45c at 9-12s, similar total battery weight, more rpm and speed, less heat, win/win =P

As far as props go the 457's will probably be ok but maybe start with 50's and work up. For the amount of money you have invested some data logging might be a good idea like eagle tree or similar, it's only about $400-$500 tops for a decent amount of sensors and full system to keep an eye on temps, rpms and they have just released a 300amp sensor as well. Any good prop guy out there like Andy Brown or similar can cut down a 457 for you if you need something in between a 50 and 57, I'd get on the water with a 50 and get used to it and then see how your temps and speed go.

Best of luck with the build and happy boatings=)

6BOOST

6BOOST
09-15-2011, 09:06 PM
Forgot to add that naturally you need a esc that will handle high voltage, there are a number of them available these days, swordfish and fightercat do some, the fightercat ones have a 200a 16s already released and a 24s 200a on the way.

6BOOST

ManuelW
09-17-2011, 06:48 AM
Hello,

seems as I need to write a bit of a longer post.

@boaterguy: Please don't get me wrong at all but as far as I read your posts up to now I'm not 100% sure if you should try to give prop recommendations on such a FE setup in a 185cm Mystic. These things are no toys anymore and a little mistake or wrong recommendation can cost quite a sum. This means by giving recommendations you also have a certain responsibility in my eyes. PropShop 5 blade props look nice but I wouldn't recommend them at all except for display or show purpose. At the moment 3-blade props is the maximum I'd run on the boat.

@ PeterPan:
As far as I understand you already have the LMT 3060/10 engines at home? When used with 12S Lipo each you'll get around 31.000rpm at a maximum efficiency of nearly 96% at 170A, resulting in a power output of 7500W. This means enough capabilities for your boat, with an Octura X457 prop which should be fine you should be driving a bit over 130km/h. For higher speeds this setup won't have any problems later on using 2x 13S Lipo which should give around 140km/h. Another setup idea would be maybe a 3060/9 on 12S1P 5000mAh 40C per motor. With the X457's you could be around 145km/h. The Schulze 303/333 is a good ESC but quite high priced and also heavy. If possible you could also try to get a pair of Schulze 40.160's of the old series, they should do the job quite successfull. For the Scorpions, the 5035 MHZ Edition is quite fine but you may get troubles with the 240A Swordfish when using more than 10S or bigger prop. But this is just what I've seen from others, I've never tried them. For further contact you can also write me an email!!

@6Boost:
A MHZ CT04 with 2x 3080/7 and 18-21S lipo for SAW purpose.... PLEASE could you be so nice to take a video of the test run? I'd also consider to take at least 2-3 big garbage bags to the lake, you might need these :scared:

And as a general recommendation:
Please be aware of high-voltage or careful. 12S lipo is okay, 14S lipo is hard on the edge but I think with more than 14S you may just play with your life. A 16S set of charged lipos can be around 67V, wouldn't recommend or try to touch both poles at the same time. If someone really knows what he does this might be okay to take the risk, but as a general recommendation?

Best regards,
Manuel

6BOOST
09-17-2011, 10:18 AM
Sorry Manuel, I was obviously too blazé about running higher voltages, and assuming someone with a boat worth more than $10000 would educate themselves as to it's running and safety, I guess it's something I took for granted in posting having an electrician as a father.

I Will post video's of all my projects when I get more time away from work, having only had 4 days off this year including weekends rc comes second. Engineering 2000+hp fuel injected turbo race cars from scratch in house, I can assure you that nothing will be coming home in garbage bags, not every "noob" is incapable of those things that most only dream of;)

6BOOST

ManuelW
09-24-2011, 07:12 PM
Hello 6Boost,

interesting that you seem to have the knowledge. But then the big question is "WHY"?

Why is it necessary to use 2x 18-21S and 3080's in this hull, beside being very dangerous? For SAW purpose I'd say its no problem to get this boat with 2x LMT 3040 and 10S1P 5000mAh Lipos per motor to 100mph, with 2x 3060's on 12S1P each you could aim to reach 125mph IF the hull alows it. So whats the point of using this big engines and so much lipo cells?

Best regards,
Manuel

6BOOST
09-25-2011, 05:30 AM
Hi Manual, are you friends with Hanspeter? I have a mono on order with him now.

How do you justify running the same speed in a 20% larger boat with the same motor? The record is held by a 53" boat with twin 3060 LMT, so I don't see why it would seem unreasonable to think that the twin 3080's are a perfect match for the larger hull for similar speeds.

As far as running 18-21s vs running 10-12s goes, we could debate all day, but you learn very quickly in drag racing that just because it's the way everybody/most others do something, doesn't mean it's the best way of doing it. You may want to keep in mind tho that I am not running the same kv motors or close to, and my total rpm will be very similar.

As far as knowing what I'm doing goes, with 9 boats, 14 motors and as many batteries and esc's, I can assure you that my path of destruction will be done with on the cheaper boats before stepping the 3080's up to their ultimate potential in the CT03. I don't want to claim speeds and list goals, I am just here to learn and have fun like everyone else, I look forward to sharing my triumphs and failures with everyone and hopefully we can all learn something together=) Work can't start in earnest until I finish building a race car for a customer, so a few months yet but all in good time.

6BOOST

ManuelW
09-26-2011, 07:56 AM
Hi 6Boost,

yes I'm quite a good friend of Hanspeter and also help him out from time to time.

And for the record: Well I'm not sure which one you mean, except one HPR06 from Florian Schönböck all >125mph cats are in the 53" size and run motors like LMT 3040. I've never seen one using 3060's. These were just a few recommendations I could give you, what you try or not is your decision.

And nice hint with the idea of different thinking, but maybe there's a reason that up to the Fighter Cat ESC every available ESC or charger had its limit at 14S (one exception: Kontronik PowerJazz could be used up to 15S). Even all the electric powered 233's used 12S setups.

Best regards,
Manuel

6BOOST
09-26-2011, 08:58 AM
That is correct Manual, all the cats are 53", NOT 67" like mine. That is nearly a 30% bigger boat, and it takes exponentially more power to move a bigger boat, so I think the engine choice is perfect AND logical, however time will tell. I will be back to back testing with NEU 2230's which some claim are better than the LMT3080, most say not quite as good, time will tell=)

You should have a paypal notice for payment for my HPR mono, please let Hanspeter know when you get it so that he can get my order ready=)

Regards, Kyle.

graill
10-22-2011, 06:29 PM
Manuel gives sage advice. Pay attention to it. :)

I have flat out refused to help folks with builds when they show they know nothing about electricity and speed or are out just to have something because they can. Sounds mean, but it removes onesself from responsibility as Manuel alluded to and hopefully makes the folks with zero FE experience think twice about building monsters that will cost them or someone else.

NativePaul
10-22-2011, 08:49 PM
I have gone with 3s batteries for my LMT3080/7's (similar kv) so that I can step up in 7500rpm steps from 15-18 and 18-21 for saw purposes. This will bring your heat down and your speed up and put less strain on the esc's

That is 7x 3s packs in series for 21s, assuming 4" on the ESC and if a typical pack comes with 4" of wire that is 64" of wire in your system, if you can cut them and your ESC down to 2" average and manage to connect them up you would still have 32" of wire and 8 pairs of bullets, many ESC manufacturers recommend having less than 8" of wire between the battery and ESC. I would ask your father about inductance before you run it and either rethink your strategy and use bigger packs or ask him to design you an ESC that will cope, because I don't think anything off the shelf will for very long.

6BOOST
10-23-2011, 05:57 AM
That is 7x 3s packs in series for 21s, assuming 4" on the ESC and if a typical pack comes with 4" of wire that is 64" of wire in your system, if you can cut them and your ESC down to 2" average and manage to connect them up you would still have 32" of wire and 8 pairs of bullets, many ESC manufacturers recommend having less than 8" of wire between the battery and ESC. I would ask your father about inductance before you run it and either rethink your strategy and use bigger packs or ask him to design you an ESC that will cope, because I don't think anything off the shelf will for very long.

Thanks for the advise mate. Some things to take under consideration, let's say you stack the packs 3 and 4 high, and mount the wired ends towards each other, all connections can be at a maximum 1" long and still reach the next pack in series. Secondly, if the esc is mounted level with the centre of these packs, it would be more than feasible to consider that it would take less than 4" of wire from the positive and negative to reach the ESC. How will the bullets transfer the current? Don't know, with castle 8mm bullets I'd say they should pass 120-160a ok? Maybe not who knows, having 9 other boats with packs from 6s, 8s, 10, 12, 15 and up, I will find out long before I burn a pair of LMT's or esc's. If it means buying more packs later so be it, with so much money invested the cost of a battery pack is hardly something I'm going to skimp on for the best result, 3s packs at this point in time allow for the most experimentation across a range of projects.

I realize that there are noobs to this hobby that regularly waste people's time and dream like a 12 yo school boy, lacking the general common sense, dedication and problem solving ability to support their aspirations. Let me be clear I am not one of those people, I am fine with people questioning my goals and generally rolling their eyes, I do hope tho that when the time comes you look back and admit you underestimated me;) I will crawl before I walk, walk before I run, and run before I sprint, but rest assured I will sprint;)

Now, back on topic, with the money invested in your boat Peterpan, there will be a number of people able to help you with your props, however to get started get it built, buy some X450's and 457's in each rotation and do some testing and have some fun, worry about outright speed when you have a handle on it. Or do what I did and buy 1/a few other boats with some cheaper hardware and cut your teeth on that while doing a thorough build of this one, then by te time you put her in the water you already have a fair idea of whats going on:)

6BOOST

graill
10-23-2011, 07:24 PM
Since your spending the cash 6boost, go with ultra lam connectors, 6 or 6.5 will do nicely for even the most demanding saw setup, though pricey (15 a pair), you get what you pay for. 8 mm are huge, hard to pull apart in the field or in an emergency and the solder job will need to be specific, plus you need to think about if your math is wrong, that big 8mm beast Will act as a heatsink in regards to your wiring, of course you know what i am referencing so i wont bore you with details. To date i have not found the point of manufacture for the ones floating around on the market.

If your investing so much into your artwork i suggest you use the best parts available, not ones that simply have no white papers or simply look good enough. :)

Good luck on your build.

6BOOST
10-23-2011, 09:03 PM
Thanks for the heads up Graill, I will look into those today=)

alhaddad
07-31-2012, 08:17 PM
:flammes-09:

alhaddad
07-31-2012, 08:17 PM
Very nice to read all the rave information from you guys:flashfire: