Simon's New Balsa rigger.

[Meniscus]

I assume the 2800kv on 4s is an inrunner, Even though the rpm is simular the outrunner will have much more torque & take a bigger/more pitch prop. Going fast is about more pitch, Providing the hull will take a particular prop. Martin.

I agree, it is very hull specific. Personally I mainly look at the thrust cone and the rooster tail and adjust from there. I have had a few models that prefer less pitch at a more shallow strut depth.

[Simon.O.]

Results !!

I had it on the water again this morning, the pond was like a mirror so was good tip rip it it up a bit. The little cat went in first to show the resident swans I was here to run.

I went for a very tame setup with the tub flat and the sponsons at 3deg AoA, consider that my big rigger runs more AoA on both.
The Cg was at 23% afterplane which is also tame for my riggers as I like around 25%
I threw on a 432 just to see if the hull would ride correctly and then a 632 for a bit more.
It was very clear that a 32mm prop is too small ( I suspected so ) so on went a 438.

That was different !! It hooked up well and ran the rigger at the correct attitude......and fast
It was easily quicker than the big Cat so I guess is up in the 80kmh or 49mph area

I did two passes each with each prop so 6 full 100m runs and the packs were down to 3.9v afterwards.....to me that means close to spent.

After each run the esc was barely warm and the packs too. The motor was stone cold as expected with the open setup it runs. will have to do this to the Cat soon.

All in all I am happy and will shake the hull a bit more on the 438 or a 437/3 and start to raise the angles for a bit more speed, then come the big props

[Ub Hauled]

hell yeah! that's awesome Simon!

[Meniscus]

Congrats Simon! Be careful running the packs down to that level. Depending on the cells, you may find that you start losing capacity over time.

I may run aggressive setups, but I like keeping my stuff around too and not having to replace on the regular basis.

A word of caution as you prop up. Keep in mind in the larger diameters, an 6 series prop is a big jump from a 4 series. Personally, my favorite props are the 6 series. For example, a model that hooks up with a x442 will be ever so slightly faster on an x637. Typically as a general rule of thumb in this size range, subtract 5mm from the actual diameter of the 4 series to get the equivalent 6 series that most likely will be slightly faster.

The easiest way to keep track is always look at total pitch which indicates how much water is covered per revolution.

I'm probably not telling you anything you don't know, but did want to make sure you were thinking about it as you increase the load.

[Simon.O.]

Ben, don't worry about my packs, I just re-read it and see where it looks bad. The packs were down to 3.9v/cell
I like what you say about the props and I'll deffo get this thing swinging the 6 series soon.

[Meniscus]

Glad to hear that was 3.9 per cell!

[Boaterguy]

Did you make the plans? if so, Can I buy them? also, If upgraded in size will this take a weedeater?

[Simon.O.]

Did you make the plans? if so, Can I buy them? also, If upgraded in size will this take a weedeater?

No plans. I build by eye, sometimes I get it right

[Boaterguy]

wow, lucky man, I would never be able to do that

[Boaterguy]

Any vids of this beaut' running yet?

[Simon.O.]

No vids. Between 2 jobs and the dodgy weather I am not getting a lot of pond time at the moment and then when I do I still need to shake this hull down to get it right.
I'll sort some moving pics when it is ready.

[Simon.O.]

I am getting this one sorted one day at a time.
Yesterday saw it on the water with 4deg (up from 3)AoA on the sponsons and the same 438 prop for a good guessed at 80kmh or 50mph.Sponsons were running dry and the whole boat looked good and ran nice.

A 637 broke the wire at the stub at least I get to keep the stub shaft as I have a retaining collar in front of the strut. It was looking real nice before that little problem.

I am now beginning to regret placing the sponsons with the ride pad as far aft as it is. The weight on the prop needs to increase so I can either add lead or cut the sponsons to move the pad end forward, thus increasing the AP length and therefore the weight on the prop.

There is a lot more to do with this hull and I love it !!

[Simon.O.]

I have been having a lot of fun with this hull until this morning. The pond was near covered in swans and a few small hulls got them to move to one end so could I run the bigger quicker ones..
I sent this one out with a 637 as it likes and did a few short ovals and then set it up to do a diagonal run at full power as my Dad and my little nephews were watching.

Something went well wrong as far as driver error and it hit a basketball size marker float dead on the nose.
The tub separated from the booms and sank, it was later retrieved by a mate who loves any chance to dive even in real cold water.
Given that it was running around 50mph on impact I would suggest a grp or cf hull would have suffered the same result.

As we know riggers have very little room for flotation in the tub, my wife said "why do you not have a bit down each" side and I said "what a wider body?" just as it occured to me that Chris Harris has a wide bodied rigger. Not a bad idea really.
I now have a pile of machined cedar on the way, from dad, and will rebuild the tub.

The sponsons are fine, booms need a bit of work.
The remains of the tub give me enough to work with and I will splice a new front on there that will be stronger.

Electrical losses will be known in a day or more as each cleaned part is dried and then tested

Here are some pics.

[Chris Harris]

Hey Simon,
DANG! Sorry to hear and see this. Your right carbon probably would have shattered too hitting a solid object at speed, just maybe not to that extent.

On my newest SAW boat there is some room for foam to be shoved in there amongst the gear, just in case. Building a wider tub however will change the lift characteristics of the hull so some setup
adjustment will most likely be needed.

Chris

[Simon.O.]

Chris, Thanks for dropping in.
I will widen the tub a little which will give me room to get some good dead tree in there and maybe a bit of foam too !
As you say it will change the handling a little or a lot and I am not too sure either. Given that I have to build a whole new front it really is a new build with existing sponsons and some of the angle numbers.
Stay tuned as this will be on the repair bench in a few days.