KNPC's 43'' Conquest build

[TotalPackage]

I've been running the big Neus for several years now and this is my take on it. In my mono I ran 12s and all sorts of 3 and 4 blade props in the 65 to 70 mm range from voodoo and prop shop and the motor handled all of them. What it comes down to is finding the right prop that the boat likes. For my mono it was a 6515 or 6715 prop shop prop with a little work done to be more mono friendly. I would figure out what prop the gas guys like running with that boat and start there. An X465 or 467 wont work that motor very hard on 10s. I agree most electric motors dont like gas props but the 2230 has no problem with them.

Mark

Thanks Mark. I like that mono too mark shes screaming!

[RaceMechaniX]

I have a similar conquest with a 2215 1.5Y on 10S2P. The hull likes the X series Octura props. I ran X457 up to X462 with speeds varying from 72 to 78 mph. For the larger 2230, i would swap out of the 3/16" step down shaft and just run a regular 1/4" flex. A X467 with added cup or a X670 will make her fly.

http://forums.offshoreelectrics.com/...light=conquest

Tyler

[jingalls007]

No challenging anyones expertise but weve yet to see a GAS prop as effective in an FE as they run in a different rpm range. Fluid has already told us this and I honestly cant remember seeing a gas prop run good . So i got to agree with him.Nothings impossible I know but stick to the octuras in the 55-65 mm range. ABC makes some good props too.

I wasn't sure so thank you for clarifying. Voodoo actually has a nitro/electric line now which I just noticed here: http://voodoopropellers.com/catalog/...cPath=21_22_26

I know the gas props were fantastic, I know nothing about their electric/nitro line. Anyone?

[knpc]

Thanks for all the prop advise, this gives me a good idea of a few props to order to start out.

RaceMechanix - I went with the 1/4 flex stepped down to 3/16 because this setup seemed right on the line of 3/16'' and 1/4'' props. I figured with the 3/16 I could run a sleeve bushing and use both sizes to give me the most options. I've looked at your Conquest build, great thread and also where I found out that the Avenger hatch would fit this hull.

10gauge - those speeds you came up with seem like they will be very accurate with the real world speed, what formula did you use to produce those numbers? From what I know this motor would do great on 12s, I just don't trust the Castle on any more than 10s and didn't want to make the leap to a Shulze just yet.

Norm - I won't be able to hold you off for long, once that HPR is done the rest of us won't stand a chance.

There are still a few things I can do until the motor gets here. I'm going to make the rails, battery trays, and finish up the hatch hold downs.


Kevin

[TotalPackage]

Thanks for all the prop advise, this gives me a good idea of a few props to order to start out.

RaceMechanix - I went with the 1/4 flex stepped down to 3/16 because this setup seemed right on the line of 3/16'' and 1/4'' props. I figured with the 3/16 I could run a sleeve bushing and use both sizes to give me the most options. I've looked at your Conquest build, great thread and also where I found out that the Avenger hatch would fit this hull.

10gauge - those speeds you came up with seem like they will be very accurate with the real world speed, what formula did you use to produce those numbers? From what I know this motor would do great on 12s, I just don't trust the Castle on any more than 10s and didn't want to make the leap to a Shulze just yet.

Norm - I won't be able to hold you off for long, once that HPR is done the rest of us won't stand a chance.

There are still a few things I can do until the motor gets here. I'm going to make the rails, battery trays, and finish up the hatch hold downs.


Kevin

If casle couldnt run 12s then that would be false advertisement but all the conponentry in it can handle more I think it would be ok . Dont take this to mean run 12s coz I really dont know if 12s with your kv is right im just saying im sure the castle can do 12s

[10gauge]

Over three years ago, I derived a mathematical equation to calculate speed for catamarans. I guess it's been long forgotten by the forum or it never really caught on. I find it very useful for approximating performance without having to take the boat on the water or build a boat by hearsay or guessing. Maybe I should repost this? I based my formula on quantitative analysis and it is a fairly accurate statistical approximation of actual setups. My formula was verified by Jay Turner on RRR and it's within 3% of his calculations. I had more time to devote to RC boats back then...

Here's my original formula:

mph = [Prop Factor] x [Prop dia] x [kv motor] x [LiPo Volts] x 0.000687
(Prop factor or pitch is 1.4, 1.5, 1.6, etc.; and Prop dia. is in inches).

mph = [Prop Distance per Revolution] x [kv motor] x [LiPo Volts] x 0.000687

Here are the original threads on the formula from February 2008:

http://forums.offshoreelectrics.com/...ead.php?t=2695

http://www.rumrunnerracing.com/feforums/showthread.php?t=25059&highlight=formula+calculating+speed

Here's the same formula for prop dia. in mm. Multiply Pitch, Dia, kV, V, then divide by 36970 for catamarans, and divide by 33610 for Hydros.

mph (cat) = [Prop Pitch] x [Prop Dia.] x [kV] x [LiPo V] / 36970

mph (Hydro) = [Prop Pitch] x [Prop Dia.] x [kV] x [LiPo V] / 33300


So in your setup, just plug in the numbers:

For a x462 prop: [1.4] [62 mm] [725] [37 V] / 36970 = 63mph
For a x465 prop: [1.4] [65 mm] [725] [37 V] / 36970 = 66mph

[knpc]

10gauge - I just tried your formula for some of my current setups where I know what the actual speeds are. All were within a couple mph, very impressive and a tool I'll be using for future setups.

Totalpackage - I spoke with Joe Ford, the guy how heads up Castle's boat dept, he reccomended not to run the 240HV on 12s. I'm not saying it wouldn't work, it may be fine for years, it may go up in smoke in a minute, or it may just shorten the esc's lifespan a bit. As a rule I never run an esc at it's max voltage, I try to leave some room for user error (me).

[dana]

For a x462 prop: [1.4] [62 mm] [725] [37 V] / 36970 = 63mph
For a x465 prop: [1.4] [65 mm] [725] [37 V] / 36970 = 66mph
i dont get it. why 37v?

[knpc]

For a x462 prop: [1.4] [62 mm] [725] [37 V] / 36970 = 63mph
For a x465 prop: [1.4] [65 mm] [725] [37 V] / 36970 = 66mph
i dont get it. why 37v?

I'm going to run 10s2p. 3.7 volts per cell x 10 cells = 37 volts

For my Sprintcat I ran an x455 on 6s2p - 1.4 x 2.17 x 1250kv x 22.2v x .000687 =57.9 the boat actually runs around 60-61mph

[Killer V]

KNPC's 43'' Conquest build

KNPC,

Two things, your daughter is beautiful, enjoy her as she is so young. Mine is 24 now. Ahh the good old days. The other thing is, and I am not critisizing, but Peter's mount looks like it is to attach to stringers. Are you going to put some in. I am curious as to your layout.


Jeff

[knpc]

Yes, I'm putting rails in. I thought it would be easier to make the rails the way I wanted them instead of having to modify rails that were already installed. The rails never come the way I would want them, not they they will be anything special its just a pain to try to shape them with a dremel while they're in the hull. I had Peter make the mount to fit betwen 5'' rails.
I'm still working on the layout, even in this big hull I somehow still seem to run out of space . I guess with a motor the size of a coke can and 4 packs it fills up quickly.

[dana]

I'm going to run 10s2p. 3.7 volts per cell x 10 cells = 37 volts

For my Sprintcat I ran an x455 on 6s2p - 1.4 x 2.17 x 1250kv x 22.2v x .000687 =57.9 the boat actually runs around 60-61mph

oh ok i get it now. so my MM comes out at 51 mph. sounds about right. ive never gps'd it tho.... i suppose i could also use this formula to calculate different props before i buy them... kinda neat

[10gauge]

Guys, remember that this formula is not based on theoretical conditions. The data to derive the constant for cats (36970) and hydros (33300) was from a pool of 30 actual and running setups. The calculated speed is an average for a particular type of hull and the data pool doesn't represent "best case scenarios or runs." It keeps the numbers modest, so be pleasantly surprised if your actual setup goes a few mph faster than calculated speed, and not the other way around.

Kevin, I am glad that 12S will work on the 725 kV motor. To bad Neu doesn't have an intermediate kV that keeps rpm <30,000 on 12S for such a large motor. I am just worried about current draw on a similarly large prop. I agree that the Avenger Pro Cowl looks great. I also like the Cyclone twin canopy design, but I wonder if it could be reworked to fit the Conquest?

[knpc]

The kv is as little in between 10s and 12s. On 10s its 27,00 and on 12s its 32,00, seems to me that 11s may be a good solution. 11s would put the rpm around 29,500, I am thinking about giving it a try after I get the boat dialed in depending on how it runs, I have the 5s and 6s packs to do it.

The cyclone cowl is nice, I'm sure you could make it work if you got both cowls and did a little cutting and fiberglass work. I modified my sprintcat cowl by cutting out the entire center section and making my own cockpit and glassing everything, wasn't too hard and came out good.

[knpc]

I got a little more done on this, I've done just about all I can do until the motor arrives. I made the stringers, they are ready to install. I also put on the vinyl decals that monojeff made up for me, he did a great job making exactly what I wanted.

Here are a few pictures