A Slow HPR 115

**m4a1usr** · 09-19-2011, 01:01 AM

Originally posted by 5150WS6

I'd thinking a pair of Neu motors just because they are easy to get, Castle ESC's and some 4s lipos. I feel lame even asking, but has anyone tried to build a tame HPR?

Mike

I dont think you can get a 115 up to a decent speed on 4S. Even into "just" the 50's. Thats a big boy. Needs more power. And 15 plus minutes run time? Thats going to need capacity. What motors do you have in mind?

John

**5150WS6** · 09-19-2011, 01:58 AM

John,
Well that's my problem. I really am pretty new to electric boats. Never had a "real" one to be honest. Everything I've done has been gas. So I really have no idea what is doable. I guess big picture is I'd rather sacrifice some speed in hopes of more run time. I could be ok with 45mph ish as well.

So I really have no idea. Maybe 4s was too small. I was just thinking trying to bump down the volts to increase the mAh's of the batts......

But that's why I'm here. I really am pretty clueless on the fast electric versions of these boats.

Mike

**m4a1usr** · 09-19-2011, 02:36 AM

A pair of 1527 1D/ 2300kv motors on 4S3P might get you to 40 mph for 10 min on 447 props providing you get the hull ride perfect. Just my conservative 2 cents. But to get into the 50's and long run times your going to need 7S minimum, most likely 8S. So its not impossible. With more voltage you get better efficiency. Say you went to 2217/ 1Y 1275kv motors and 7S hyperion 45C 6500 packs. With 3P and the same props 50 mph can be achieved. But 15 minutes on calm water Vs 15 minutes on 2 inch chop can be worlds apart in power consumption. Dynamics can be a ball buster.

John

**graill** · 09-19-2011, 05:55 AM

The difference between an FE boat and a gas boat are night and day. So is the technical knowledge to get one running without it self destructing due to builder error. (Grin)

I dont usually reply to folks asking to go fast and never made an FE boat but you also seem like you can take advice. Listen to the racers and some of the builders here, they know what they are talking about. If they tell you to start small, then do so. That said here is a link and the combos for the 115 that arent water rockets, fast but not insane. And as always, its your dollar that you will be wasting if your math is wrong...

http://www.swissmodelpowerboatteam.ch/

under links/115

**5150WS6** · 09-19-2011, 01:19 PM

Thanks guys.

Graill--I appreciate the advice. I'm actually old enough and have made enough mistakes building gas boats to know that this is a whole new world. That's why I'm looking to you guys to school me a little. I've converted everything I own almost over to brushless lipo combo with the exception of my boats. I've had 2 HPR cats and sold them both(not happy Bob, not happy) So I'm looking to get another. I want to eventually build another 233 but thought I'd better start small and less insane than every other project I've done. :) With the quality of HPR's hulls I really have a hard time wasting money on anything else......

John--I see what you're saying. It's the same with cars right? My 4000lb Camaro back in the 80's had a V6 and sucked gas.....My Iroc Camaro with the V8 got great gas mileage......same car, the V8 just didn't have to work as hard to move things.....taking less gas. Same sort of principal with the boats I'm assuming? I guess where I'm going with this is I'd like to have a boat that could eventually be a 80-90mph boat but I certainly don't want to start out with that. I'm in San Diego.....so I have running places 365/24/7 practically. I'm just trying to go against every fiber in my body to go big and just start with something a little smaller and conservative.

How are you figuring all those numbers......with the props and batteries. Is there a good formula to figure that out? Or is that sensai experience speaking? :) I think I can do it, there's just to many dang choices for combos between motors and props and batteries.

I don't mind going expensive.....I'd rather spend money and have it done right than to be cussing at the lake teaching all the kids new words! :D

Mike

**Rumdog** · 09-19-2011, 01:33 PM

Twin 1515 1y's on 4s2p each will get you low 50's no problem.

**LarrysDrifter** · 09-19-2011, 01:38 PM

I have 2 for sale with water jackets right now in the swap shop. New, never used 1515/1/Ys.

**m4a1usr** · 09-19-2011, 02:50 PM

Disregard my previous comments. I read HPR135 not 115. Dont know why I had them confused.

John

**tiqueman** · 09-19-2011, 04:21 PM

Yup, my 115 is mid 50s on 4s, mid 60s on 5 and mid 70s on 6. Castle 1520s. Vids on youtube under tiqueman97 and bill34207

**ManuelW** · 09-24-2011, 06:59 PM

Well I just read not everything carefully but 2 opinions:
-18min runtime is not really possible I'd say
-on 4S1P per motor (2x 4S1P overall in the boat) 75mph are not even a little problem in the HPR06. Have already tried it myself. Okay, runtime is limited but its a sport setup, nothing for SAW purpose. For SAW I already ran 6S1P for BOTH motors, fastest heat was 97.5mph. So in this case I've to correct John, its possible.

@ Mike:
So what would you want and what are you willing to spend on the setup?

Best regards,
Manuel

**graill** · 09-24-2011, 10:49 PM

If you want to do a 2.33 with an 18 minute run time let me know, it barely got off plane but did it several times. Have a couple grand on hand. (Grin)

**Algroove2000** · 02-21-2012, 07:54 PM

You could do like I did and run outrunners.... It's very uncommon but it works great. I use twin Scopion motors running on 12s per side for an eventual 85 - 90mph, but with the current prop setup it is doing 70MPH and run times of 20 - 25minutes. With Scorpion's huge choice of motors you could find something at a descent price with the speed and runtime you are looking for.

**wataslyd** · 02-21-2012, 08:57 PM

Originally posted by Algroove2000

You could do like I did and run outrunners.... It's very uncommon but it works great. I use twin Scopion motors running on 12s per side for an eventual 85 - 90mph, but with the current prop setup it is doing 70MPH and run times of 20 - 25minutes. With Scorpion's huge choice of motors you could find something at a descent price with the speed and runtime you are looking for.

i went to my lhs sunday and i was pondering the same but on an out board running a 4 pack out back of a long boat ,trying to build a scarrab ,dope smuggeling boat lol sorry but those boats are fast ,but the guy there told me that ,out runners use the prop to cool them "airplane app" and he told me that id burn the motors up and also water isnt there friend ,so by you saying that has me strongly trying out my theory..thanksa and if theres something i need to know about running 4 outboards or more please school me

**Algroove2000** · 02-21-2012, 09:42 PM

Originally posted by wataslyd

i went to my lhs sunday and i was pondering the same but on an out board running a 4 pack out back of a long boat ,trying to build a scarrab ,dope smuggeling boat lol sorry but those boats are fast ,but the guy there told me that ,out runners use the prop to cool them "airplane app" and he told me that id burn the motors up and also water isnt there friend ,so by you saying that has me strongly trying out my theory..thanksa and if theres something i need to know about running 4 outboards or more please school me

Well I built a simple cooling system for my outrunners. With the current prop setup, I'm using a little more then 1/3rd of the motor capacity. It runs at 70mph and barely gets hot. Scorpions are known for their hot running motors, they usually run hotter then other motors but can also take way more heat then most motors. I could runs the current setup all day long with 20 - 25 minute run times and never have a problem with the heat in the motors. I thought you were looking at building a dependable slow HPR?? Now we are talking go fast boats? With quad outboards??? Hardly seems slow, and a Scarab V Birth is a totally different animal then an HPR Cat.

A Slow HPR 115

A Slow HPR 115

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