TopSpeed 2 - PSFEMBC First Race for FE Conversions

[Darin Jordan]

Well... the Puget Sound Fast Electric Model Boat Club (PSFEMBC) held it's second annual Todd Wilkens Memorial Race this past Saturday, and we debuted the TopSpeed 2 OPC tunnel FE conversions for the first time.

Stock TopSpeed 2 hulls with modified radio boxes for FE.

REK Lower units

Stock SV27 Motors and ESCs

4S1P Lipos

So here's my summary of how these things worked... AWESOME!!

The video link below is for the first heat on the water... We had each ran a couple of practice and tuning laps, but this is the first time we put them in the water to race, so we were all getting used to driving them, getting steering dialed in, etc...

Mine (Oberto colors) had a full-bladed ABC 42x55, I think Brian (Orange... out front as usual...) was running a Prather 220, and John (Yellow) had an X642... Amazing that with that range of props, they still ran this close... but they did, and they did for the next two heats as well...

The boats handle GREAT for these speeds... I GPS'd mine after the second head and got 33.6 MPH... so I think about mid-30s once they are dialed in is about right...

We ran 10-laps for the first two heats, but decided to cut it back to 8 because we were pulling about 3400mah out of the packs, which was approaching the 80% capacity mark for the packs we could fit into the hulls... 8-laps was about 1-mile... Battery temps were approaching 140-degrees... With some setup and dialing in, that may come down some, but as you can see from the video, they are already running pretty well...

Brian tested an AMMO 2300KV motor and the boat GPS's at 41mph... However, the handling was not that great... Since these hulls were designed for the stock 3.5cc motors and about mid-30s... This may just be the way they are... Brian tried a TON of changes, all having negligable effect... (If there is a trick to making them really work at higher speeds, we'd love to hear about them...)

As a result, we've decided at this point that we will push for this class to run with the SV27 power system for the time being... We think that it will be much less frustrating for those new to tunnels to make this system work and the racing did NOT suffer from the slower speed... It was FUN, and I can't wait to get six of these out there at the same time... Watching Brian's go with the AMMO motor in it, however, really showed how exciting this has the potential to be if we can get them to handle at those speeds...

Looking forward to getting these out there again!

Here is the video for the first heat:

 

[moparbarn]

darin, the ts2 CAN handle the higher speeds. i am NO testament to this, as i still haven't found the "handle" on mine. my son, however, is running 52.6 (gps) in heat race trim. i have tried to duplicate his set up, even using his 'cut' octura x-440. has gotten better, but i feel driving style has a good bit to do with it. maybe i need to borrow his stick radio, and put down my pistol grip. it took us about 6 weeks of testing and tuning to get his right for him, just need to keep working on mine. his handles good enough to win .20 tunnel at the d-12 race at greenbriar last weekend. kepp playing with it, once it's stable in a straight line at speed, learn to keep the power on in the turns, lower speeds seem to make it handle worse (at least that what my son tells me ). looks like a fun class, good luck with it.

later,

robin

 

[Tim_Duggan]

Thanks for the report Darin! I've been waiting to hear how your new boat ran! Unfortunately I can't watch the vid - streaming data is blocked on my connection. If the file is not too large, any chance you could email it to me?

As Robin has said, the 30" long TS2 is capable of running at much faster speeds. Mid to high 40's no problem.

Do you have any idea of the rpm these SV27 motors + ESC's are producing on 4s - going by the props you are using and the speeds you measured, I'd say you are pulling about 18-20krpm (if it's not set-up limited). If the boat set-up is way off for various reasons then that would hurt your speed by a lot. Hopefully some of us on here can help point you in a direction that can net some more speed.

Using the SV27 running gear and 4s1p LiPo seems to make a whole lot of sense for costs and parity. I think if you can refine the boats and get the speeds up into the mid 40's you would find that a lot of the Sport tunnel / Stock tunnel guys would take a lot of notice!

Tim.

 

[David Kingston]

darin,

great vid footage of the tunnels.

Good the see them racing so close.

Tim

As far as i know the aqua craft motor ESC combo is 1700kva with a 45amp speedy. Great combo, proven in a range of mono hulls in our club here, and as Darwin has show, also tunnels. Im sure the motor could be proped up a bit more with a bigger ESC,

with out hurting it. Being on the tunnel, air cooled it wont get that hot.

So as for rpm on the motors you are looking at

25000 no load

round about 22kloaded maybe a bit less.

the AMMO motor of 2300kva would give you more speed, but again if run with 45amp esc you wont be able to get a bigger prop range on there without smoking something. Guys here run a x440/3 in monos with that motor and hit 68kmph with NiMh cells so lipo will be faster. Break into the 70's. The ESC's are warm with that setup. Prop less heat with the lipo as there would be less weight.

To make them go faster you would have to pull a bit more amps. The boats looked like they were riding nice and light on the water so setup is not the issue. Personally i really like those motors. I would consider one but with a 70 - 80 amp ESC. Just not sure on the max amps for the motor itself.

david

 

[Jerry Wyss]

It looks like good, clean, fun Darin,, nothing wrong with formula racing, it's very exciting to watch and

the neighbors probably love it, yeah?

Thanks for the vid,

JW

 

[raptor347]

The boats ran very well for the first time out. I got out a ran mine for the first time the day before the race. The SV motors are capable of pulling lots more prop, but we're limited to what would fit under the cav plate (wanted to start off as stock as possible). I ran a 45x55 the last heat and the boat was running 35-36 mph, good trim nice and light on the water. We aren't going to get much more out of them without going to much bigger props. I don't know that we need much more speed for a club/spec class, 6 or 7 boats on the water with pretty even performance is going to make for great racing. I think we'll innitially run the SV system with the prop limit being what ever fits under the cav plate as the stock class. We can always add a superstock class if there is enough interest.

David,

We're running cooling on the ESC's and motors, they get too hot if you don't cool the whole package.

After the race I bolted the 2300kV Ammo motor on with a y537/3 running the stock SV ESC. GPS'd at 41.3 the first run but wasn't real stable (big understatement, I have a lot to learn about tunnel tuning). Motor was 120F, ESC 150F, batteries 140F. Motor and batteries were within safe temps, I don't know how long the ESC will with that abuse. That being said, mid-high 40's is very possible with a dirt cheap power system.

I'm planning on building a second boat to run the ammo system just to see what I can get out of it.

Jerry,

If I drive out your direction, would you give an FE hack an education in tunnel tuning?

 

[Darin Jordan]

I'm planning on building a second boat to run the ammo system just to see what I can get out of it.

Hmmmm... I suppose that means I need to put together the second one I have here as a "mod" as well... Guess I'd better get on the phone to Ray about another lower unit!

 

[Tim_Duggan]

Ok so if prop diameter clearing the cav plate is a limiting factor, what about running props with more L/E pitch (or would that mean the current draw is getting too high for the aquacraft ESC?)

Similar tunnel hulls with nitro engines and about 22krpm will do mid to high 40's with an Octura 1440 prop cupped to kill off the lift. The ABC 40x53 2 blade is a better handling prop on the TS2 and capable of some decent speed without cupping - just sharpened and balanced.

This is a really interesting thread - I hope it keeps going...

 

[Jerry Wyss]

Jerry,If I drive out your direction, would you give an FE hack an education in tunnel tuning?

i'm a little nervous here, not sure if your talking about Dunlap or me,, But Yeah, No problem here!

I have to test a New XM head config this weekend with Jim Hill if he's on vacation then, but if not

I'd like to help out, heck yeah

I really like watching the,, what I call Formula racing,, everybody has the same equipment??

The little Sport I/B's at our club get everybobys attention, wives, kids , everybody,,, I had no idea

they would end up being that fun,,,, i don't have one though,, too tempted to put a 21 in there :wacko:

Still have my ph number? I think I have yours somewhere here, i'll look.

JW

 

[raptor347]

JW, that was directed at you.

I'm out of town this weekend anyway (10th wedding anniversary). I may not be able to get together before the weather goes bad (getting ready for the LA SAWs). It may have to be a spring deal, but we'll see how ugly the winter gets.

I lost your number when the last computer went belly up.

I have to agree that the formula racing is fun both to watch and compete. It's not as flashy as the high power classes, but it's more accessable to everyone.

 

[Darin Jordan]

Ok so if prop diameter clearing the cav plate is a limiting factor, what about running props with more L/E pitch (or would that mean the current draw is getting too high for the aquacraft ESC?)
Similar tunnel hulls with nitro engines and about 22krpm will do mid to high 40's with an Octura 1440 prop cupped to kill off the lift. The ABC 40x53 2 blade is a better handling prop on the TS2 and capable of some decent speed without cupping - just sharpened and balanced.

This is a really interesting thread - I hope it keeps going...

I think there is definately more to be had with the existing system... The thing that doesn't directly translate from Nitro to Electrons is that the FE motors have TONS of torque, and RIGHT from the bottom up... There is no "winding it up"... You hit the throttle and it LEAPS out of the water onto a plane and you're gone... So I'm not sure how props are going to directly relate... It does generate some interesting questions and thoughts on things to test... and I will definately check out the idea of maybe going smaller on the prop...

 

[Tim_Duggan]

The thing that doesn't directly translate from Nitro to Electrons is that the FE motors have TONS of torque, and RIGHT from the bottom up... There is no "winding it up"... You hit the throttle and it LEAPS out of the water onto a plane and you're gone... So I'm not sure how props are going to directly relate...

Darin,

I see this to be a huge advantage with FE, even though it means essentially starting from scratch with selecting props. With Nitro we have to select props to suit the narrow power band of the 2 stroke engine.

That may not be the case with FE - I think what might become the limiting factor is the prop's effect on handling. props with more leading edge pitch or constant pitch like the 14** octura's can upset the handling of tunnels greatly and often requires different set-ups and prop tweaks to get them to work. This leads to my next question;

Raptor347,

Did you try the Ammo motor with any X series props? I'd be interested to know how it works with an X637 or X437.

Tim.

 

[raptor347]

Raptor347,Did you try the Ammo motor with any X series props? I'd be interested to know how it works with an X637 or X437.

Tim.

Tim,

I've got a grand total of 9 charges through the boat. That equates to about 7.5 minutes of testing with the SV motor, 7.5 minutes of race time (including the heat in the video) and about 4.5 minutes with the Ammo motor. So I really haven't had much testing time, but we'll get it figured out. I'm absolutely possitive there's potential for mid-high 40's with the Ammo motor. The second boat will be here soon so I'll get to test quite a bit more with both setups.

I've got a stack of props to try. The Y537/3 I used was my prop of choice for both my small mono and sport hydros (I have 5 of them in different stages of modification). I could be completely wrong, but I've always gotten better performance for high reving FE applications out of the sharp tipped props vs spoon tipped. This could be a case of me not having enough experience with the round blade props.

 

[Tim_Duggan]

Brian,

I must confess I've never tried the Y537/3 on a tunnel hull before, and have zero idea about prop selection on any FE boats!

I'm just trying to establish if the severe differences in handling you described were because the motor and prop were changed at the same time. It may have little do do with the motor and all to do with the prop (or possibly the other way around )

Tim.

 

[moparbarn]

i don't think a "Y" series prop will be a good choice. they are lifting props, for hydros. i would think getting too much of the rear of a tunnel out of the water is going to cause handling issues. the "X" or "M" series should be better choices. on my .21 tunnels, the x-437/3, 438, 440 or 440 are good choices. on a fe boat, the higher pitches (x-540 or x-640) might be what you need. when you're balancing on a bubble of air, you want the back of a tunnel fairly well planted. try to fly it with trim and balance, not the prop. chine walking and prop walking would be the result of too much lift from the prop. the 3 bladed props seem a little more stable in the turns, but give up a little speed to a 2 blade. motor height affects turning ability a lot on tunnels, imho. keep us posted on your progress. .21 tunnels is all i do, got 11 of them. might be electrons in my future....... formula or spec racing is fun and good to watch. depends more on driving and setup, not $. keeps the fun factor higher, imo.

 

[Darin Jordan]

Hey Guys... We raced the FE Tunnels again this past Sunday at the "Pumpkin Scramble", hosted by the Puget Sound Model Boat Club. Jerry (Dunlap) got some great shots with his camera of my boat at full tilt... We're getting them closer to being dialed in... Still a ways to go, but we're finding out more info each time out... The main lesson we figure out this past weekend was that you can basically throw out any ideas you have on which props to use for this based on what Nitro does... FE is going to need something pretty much completely different... Also, we're not quite up to speed with the Stock 20 boats yet... They've got another 4-5 mph on us from what I can tell... at least with us using the SV27 power system...

So, here are a couple of shots of mine. Give Jerry Dunlap the photo credits... great shots!!

 

[Kris Flynn]

Hell if they are not going fast that first shot looks like they are! Well done guys, let me know what you throw a 'hot' setup on the back of one for some real speed ;-)

 

[Darin Jordan]

Hey Gang,

I've completed updating my TS-2 with the new full length radio box... This was the basis for the drawings I provided... With everything located as it is... balance point is about 9", which is 1/2" behind where it's recommended, so I have plenty of room to move it forward... It handled great a 9.5" last time out, so I'm expecting similiar results when I get to test it again...

All up weight for this hull with 4S1P of Poly RC 20C 4350 mah pack (actually... two 2S1P 4350 packs in series... so a tad heavier than a 4S pack by itself)... is 5lbs 12oz...

I've made some rough drawings of the pieces used to make this box in case anyone wants to try one... You can download them from the following link... they are in .pdf format, so you'll need an Adobe Acroreader:

TopSpeed 2 Radio Box Drawings

 

[Moparbarn Jr]

Darin,

All I can say for driving a TS2 at higher speeds, say 45 and up, for me has been to use an old or new stick transmiter and get it to lay out good in the straights; in the turns, just before the turn lightly bip the throttle to set the nose; then give it all you got and think dirt track or sprint cars, sliding will slow you down, but your probably going to fast to make it turn on the boueys anyway with a ts2 (only around 50ish). If you start what I call swishing (the nose will move in a circular pattern, generally if looking at the boat head on, the circle is going counter clockwise), then your motor is to high or if you like where the motor is it could be that you are over turning the boat. I usually keep my throttle high, motor spun up, and carry as much speed as possible into and thru the turn. A little sliding is ok (caused by prop push), too much and it will chatter on the water from side to side, not good, this will slow you too much and cause a split second bogg that at the wrong time can cost you a lot of the sling shot affect that is created by this driving style. May not work for you but the further on the edge I am the better I drive. Also know that I drive my boat so loose that at any time and almost any speed, I can hook my boat and do 360's all day long. It's a fine touch, but builds the adrenaline much higher! (Mmmmmmmhhhh, Adrenaline, mmmmmmmmmhhhuuuhhhh) Sorry got excited! Anyway, the reason I use a stick transmitter is that throttle is like cruise control so I can focus on stearing. (And the good Blues in my left ear.) Lanes 4 and up become your best friend. Don't be afraid to run a larger course. Driving like this with only a special mild mod to a K&B on a tuned pipe gave CMB's, that I believe were setup darn good, a big fit! The TS2 has a lot of moxy, you just have to have big ones!

 

[Bill-SOCAL]

My conversion is almost ready for the water. Should be this weekend. Here are a couple of shots