ISIRC10

For my second project this summer, I will venture into this area of boating. I have built a few airboats and am now going to attmept to build an outrigger from the predator plans. I will be using balsa and plywood, and will probably end up making my own hardware. I am only 15, so I have a lot to learn, especially in this area of RC. I plan to power the boat with a plain-ol' 550 motor, then stick in my Mamba Max 5700kV once it comes from Tower Hobbies. I worked my butt off to get it and my bugdet will have to wait awile to be fully recovered. I hope to finish the build in a two week timeline... then again, I am usually pretty bad at following them, so we shall see about that. I will post some pictures every step of the build, and would like some input as to how I am doing.

Futaba 2pl radio / reciever
Futaba s3010 HT servo
7.2 v 3000mAh NIMH battery
550 motor (brushed)
Dynamite Tazer 15t ESC
plastic prop from some old boat

- hope this one isn't going to sink

ryan_t888

5700kv is quite a lot. It will work but you will have to keep a good eye on temperatures very frequently until you are confident in running for a specific time period. Start with an X427 for that motor and check temps every 30 seconds for the first bit. Please read the thread stickied at the top.

Ryan

ISIRC10

I have just read the thread - it helps a lot, and it seems that I fall into a good range. the 5700kV is just a MAYBE last resort if I don't like the speed I'm getting from the stock motor. its meant for my T4. Will a water cooling jacket help with heat issues? Thanks for the great tips - learning a lot already!

ryan_t888

It's already assumed a water jacket will be used. It's mandatory for FE.

Ryan

Simon.O.

I'll help you out here if you want.
I have a rigger that is very similar to the predator. The overall dimesions are similar and so are the critical angles of attack etc.
On a stock 550 drill motor not a lot happens.
Riggers need rpm and a prop to match.
I use a brushed 540 car motor of 23t giving me 27,000 rpm (unloaded)
This is fed via wire drive to a 431 prop, believe it or not the 431 is quicker than a 531.
I have learnt a lot by designing and building my own hulls and now believe I am in a position to offer advise to those who want to go the same way.

Key points of advice for a rigger.
Angles of attack are critical.
Strut settings make the whole boat do a lot of things. Jeff Wholt wrote alot about this and I learnt from it.
Weight is your enemy.
You can make a rigger of this size go well with a brushed motor on Ni cells ( good ones )

Last but not least, listen to Ryan and a few other here as they do know what they are talking about. This I do KNOW.

Fiend

when I was building mine (small predator) someone told me not to bother too mutch about the weight, I think that mean light dech without internals (my thought) as for example mine boat weighed les than 300g empty and about 800g with hardware, engine, esc and li-po... so I think You can put as mutch weight that makes power as you wish and the bigger "power" density the better.
besides I run 5070 rpm/v feigao S motor and it works great in my aplication on 2S li po. I used y531 x632 props. x62 was really fast.. the crusual thing is to choose good esc and batteries ir you want to go really fast

ISIRC10

What do you mean by angles of attack and strut settings?

I figured that going light would help - the same applies to most things (cars - airboats - planes)
the frame is very light - 3/16 balsa skinned with 1/32 plywood. The transome is 1/4" plywood.

Should I really make the sponson insudes out of foam (the pink stuff?) if so, should I use it anywhere else in the boat?

Thank you for your informative answers!

Fiend

You don't relly get the weight I was talking about..

regarding angles he means that sponsor angle to a water is quite critical to these boats - it must be a certain angle and not less or more or it will perform not at its best. The strut angle can regulate how mutch vertical forse you want to get, the ideal is when strut angle is about 0 degrees with water, than most of trust is where you want it to be.. best way to arrange best strut angle is to test it in the lake..

ISIRC10

sorry, I was replying to the post before yours, just as you posted yours. I am still going to go light as my initial setup won't have too much power (maybe even not enough)

thanks for clarifying that up!

Simon.O.

The angles I refered to are the sponson planing surface to water angle. With the boat set at its running attitude the sponson bottom should be at about 4-5 degrees up.
The strut settings do a lot. I will dig out some interesting articles for you soon. In summary is this: Changes in strut depth will alter the AoA of the sponson and therefore the behaviour of the front of the boat. Changes in the strut angle will raise or lower the stern and determine the behaviour of the rear of the boat.
Depth = front
Angle = back.

To demonstrate this I played a lot. With the strut too deep the front ran very wet and therefore could not get best speed.
This shows up even more with a vintage style shovel nose hydro. If the strut is too shallow the front gets too much air and lifts too high.....blowover time.
With the tail shaft angled down the back hopped all over the place losing thust, this is where Fiend refered to 0 deg being optimum. Mine is 0 deg on the hydro and the rigger.

sportygreg

My Feedback: (2)

Here is my Predator "bat boat" with Graupner speed 600 and 1/8" straight shaft and a classic round nose hydro I am working on that will use the same setup.I like to make 'em old school-maybe not as fast but a lot of fun![8D]

ISIRC10

Nice boats!

I am currently wondering whether to do a straight shaft or make my own hardware (flex shaft). I will use the straght as a backup if (or when) my setup fails, assuming its not in the middle of a lake

here are some pics of progress - got back from work today late so couldn't get much done. hull weighs 80g so far without electronics - they are just a mockup in the picture, not the real ones that I am using.

sportygreg

My Feedback: (2)

I'm sure a flex shaft and strut is better for performance but I just happened to have a few straight shafts and stuffing boxes laying around as well as some brushed motors and ESC's.I can always convert to flex later if I want to and maybe even brushless if I can spare the coin! Money for toys is getting harder to justify to the old lady![8D]

Fiend

I made mine hardware from zero. And it works perfect, is light too, and is fully adjustable. To make proper strut or coupler you'll need a special machine to make some drillings etc.. flex shaft is from 1 mm stainless steel rod.

ISIRC10

Nice hardware man! I have decided to just install the shaft drive for now (to save some time - I'm going to Florida next week and want to have it finished)
once I get a hotter setup I will probably try to make the flex shaft thing.


How is the flex shaft a single rod? wouldn't it have to be wound like a cable?

ryan_t888

If you have rear sponsons / rear ride pads on the hull, your prop shaft must be run parallel with the water using a low lift prop.

Fiend is using a wire drive.

I prefer flex shafts only. For this project a .130" flex with 3/16" shaft stepped down to 1/8" will work great for brushed and brushless applications.

Ryan

sportygreg

My Feedback: (2)

The rear sponsons on mine are mounted to the sides instead of the bottom so the rear rides lower in the water than normal and the prop stays submerged.[8D]

ryan_t888

The sponson on mine are mounted on the side of the tub. When properly setup the prop shaft must exit so that the center line is even with the bottom of these ride pads. At the most from the top of my head it is about 1/4"-3/8" deep and parallel with the waters surface.

I've never heard of a submerged drive on a hydro before, if it is submerged it is setup wrong.

Ryan

Simon.O.

I mentioned before that my rigger is similar in size to the predator.
It is brushed powered on Ni cells ( good ones)
There are no rear ride pads, ride shoes or call them what we like. I was told that on brushed I need them, well that is BS !
Straight shaft riggers can work. However I reccomend that you try a wire drive ( very low cost ) or a flex to get the appropriate thrust angles.
Get the CoB / CoG correct and the appropriate sponson angles and you can make a brushed rigger get up and go, just ask Jay Turner and Ed Hughey to name a few.
Plastic props CAN work.

Here is the deal. With a well built home made rigger running a brushed can ( stock or above ) on 6 x Ni cells ( good ones ) you can make a rigger boogie !!
It will not take out honours at the next LA saw's but you will have fun with it. I DO !!

Design it.
Build it
Run it.
I do.

sportygreg

My Feedback: (2)

I scrounged the parts from Ebay and will be putting in a flex cable and strut with an Orion 15T motor and an Octura 1732 prop.The roundnose will have flex also with a 20T Photon motor and X432 prop.I may build a Garwood Speedster next with straight shaft and Grauner speed 600 just for fun![8D]

ISIRC10

well, I am back from my vacation... the Mamba isn't here yet and tower says late august [:@]

so that leaves me time to finish up the boat and play around with the stock setup. I have started making the sponsons - foam cores and all, and have epoxied in the stuffing tube and the aluminum tubes attaching the sponsoons to the center hull. The center hull has been covered with marine grade polyurethane on the inside. I am planning on painting the outside with some made up paint scheme, I have attached a basic layout of it at the bottom of the post. The letters will be vynyl prints...

...getting back to the present situation, I have made a 7-cell out of old nicd cells (1700mAh) and will see how it runs on them... I really don't know whether I will need the rear ride pads (sponsons?) with my "incorrect setup" so I will try without them and experiment with their placement later. I have also made an aluminum water cooling thing for my ESC and routed the lines. more pics to follow.

ryan_t888

Remove the Honda graphics and you will gain an easy 5mph.

Ryan

ISIRC10

LOL! what should I put there, Ford logos?
I'm not going for any speed records so I guess honda will fit the boat well!

here are the pics:

CadillacDTS2001

Bahahah! ford... no that will make the boat go 7mph slower.
better leave the Honda graphics on....

detox

Found
On
River
Dead

Fix
Or
Repair
Daily

Frigged up
Old
Rebuilt
Dodge

ETC.