Simon's New Balsa rigger.

[Simon.O.]

Power !!

A bit of back story and some of my research.
The previous hull was run with a 2980kv 540 S-size can with a water coil via a 100 watercooled esc. The pack was 3S 1800mAh 40-50C in a 2P config giving me a potential of 140A at 11.1v thus 1400W

With a 637 prop
My findings were: Esc=warm, Motor=quite warm, packs=cool
My assumptions are that I am running under the 1400W mark and can hope for similar in this new setup.

Given that a 637 with my new projected setup will be a high end prop I believe I am safe so far.

Here is where it gets different. I have gone form 3S2P to 6S1P with the same packs
The motor is a 1800kv 500 size OR. Turnigy Typhoon

I will be gentle with them as they have another use later. If this whole 6S setup is a go then a set of new packs will be on the plane real quick.

Enough from me for now. The water will tell the truth !!

These are my figures based on my findings are are in no way a reccomendation. Please use my data as a guide only !

[Simon.O.]

The motor is here and it is fitted now. It make a beautiful sound during testing!!! SHE upstairs gave me hell for a bench run when I hit wot briefly.
The shaft and especially the strut was kept cool with a very wet sponge to simulate water time.

Here is what it can look like in my mad cave, it is very busy here as I need to get the new recovery setup of the Patrol boat going before this rigger hits the water.

Enjoy !!

[Meniscus]

...I will be gentle with them as they have another use later....

Simon, I'm hoping that what you mean by "gentle" is starting with a smaller prop. I would be concerned for the ESC if you plan to go partial throttle.

Is this X637 detongued? It may be a consideration. If the motor holds up, you should see around 64mph by my calcs, assuming the motor is 85% efficient. It could be higher based on 6s.

[Simon.O.]

Simon, I'm hoping that what you mean by "gentle" is starting with a smaller prop. I would be concerned for the ESC if you plan to go partial throttle.

Is this X637 detongued? It may be a consideration. If the motor holds up, you should see around 64mph by my calcs, assuming the motor is 85% efficient. It could be higher based on 6s.

Ben, I promise I will spin a smaller wheel for its shake down runs, I have a 438 that is basically deburred and smoothed a little on the back face (fwd side) nothing flash but will be less of a mouthful than a 637
The speedie is on borrowed time and I will be lucky if it takes a few runs, if not then no drama as I will have a 80HV unit on the plane quick time. there will be more speedies in that packet too

[martin]

I also got 64mph on my calcs & 57mph on the 1438. Martin.

[Simon.O.]

Dang, I was hoping for a little less speed off those props as they are the starters for this setup !
Oh well lets see what happens in the morning if the weather is good. I have set it for 3deg on the sponsons and 0 on the tub as this should be a tame set of angles and allow me to get my head around the whole build......as it scoots down the pond approaching 50mph !!

Here are a few pics of it rtr, or as I like to think of it as bridal pictures. She will never look this good again !!

[Simon.O.]

I have had a look at my calculations and can see one thing if no other. This will-should have a lower shaft speed than my big rigger.

If we ignore some of the variable factors and go with true numbers we get:
** using 4v/cell as a comparative voltage, we all know loaded volts are lower.

4S=16v x 2800kv = 44800rpm
6S=24v x 1800kv = 43200rpm

Negligible, yes but the important thing is that I have run my hand built struts and shafts at these rpm with a lot of success and that for me is a small comfort.
It will still be a bit wild as I pull the trigger on its first run as the speedie despite being labeled as 6S capable will be the determining factor.

Let's wait and see

[Ub Hauled]

Simon, first thins first...
I thought it was sacrilege to cover a beer mug down under?! LOL
She is looking great mate... I m sure that I am not alone when I say...
VIDEOS PLEASE!

[Simon.O.]

Simon, first thins first...
I thought it was sacrilege to cover a beer mug down under?! LOL
She is looking great mate... I m sure that I am not alone when I say...
VIDEOS PLEASE!

Jan, that is no mug, it is a 1L Stein from a long ago beerfest, makes a good boat stand too !!
Vids may come , if this thing rocks then I'll get someone to shoot some film for me.

[Ub Hauled]

1 Liter?! Niiiiiiiiice
that gives me a better idea of the size of your rigger...
=)

[Simon.O.]

I ran it today and have learned a LOT !
I have broken the cardinal sin of FE and made too many changes at once and paid a small price for it.
This is a new hull with a very hot setup so that was a bad idea I should have seen yesterday
Good points
I think this hull will fly !!
The open area for the OR motor is deffo a winner and works, after two less than wot passes it came in and the motor was stone cold, esc and packs were just warm as expected.
The hull is fully watertight even with a wet section in the middle.
The no-name 100A esc survived even with a lot of part throttle
The motor is fine, just too dang fast for this setup !!

Bad bits
The 1800kv motor is too wild, some reviews suggest it may be 1900kv This would give me about 35krpm (loaded) assuming 85% eff on the motor.

The hardware was not up to the task as when I went for wot the prop walk caused the rudder mount to shear and let the rudder hit my new 438 prop is near buggered and rudder mount broke off and I lost the rudder, no big loss but a lesson in component strength.

Conclusion

I have a new stronger rudder mount on now and will give the whole thing a whirl again in the morning with a different setup.

I have now refitted the older 12S can that has run a lot on 3S with this speedie to a 637 and that will help me shake down the hull before I attack it with more power.

I have a lot more to learn while playing with this new hull.

[Ub Hauled]

Congrats!!!!

[martin]

I have had a look at my calculations and can see one thing if no other. This will-should have a lower shaft speed than my big rigger.

If we ignore some of the variable factors and go with true numbers we get:
** using 4v/cell as a comparative voltage, we all know loaded volts are lower.

4S=16v x 2800kv = 44800rpm
6S=24v x 1800kv = 43200rpm

Negligible, yes but the important thing is that I have run my hand built struts and shafts at these rpm with a lot of success and that for me is a small comfort.
It will still be a bit wild as I pull the trigger on its first run as the speedie despite being labeled as 6S capable will be the determining factor.

Let's wait and see

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.

[Simon.O.]

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.

The 2800 is deffo an IR, That is the one in my Big Rigger that is now having major surgery to fit a T-180esc and new packs

I ran this hull again this morning with the old setup from the hull it replaced.
Same packs but 3S2P this time and same speedie ( bless the cheapo 2-6S ebay special)
This time I threw in the 540-12S 2950kv very abused motor.
With a 637 it went very well and the sponsons were a little wet but that is to be expected at lower speeds and at 3deg AoA

Overall I am now happy with the hull and will pull a 1600kv OR motor from the Big Cat to spin the props in here , that means I get a 1800kv Typhoon left over and one motor missing from the Cat..........Easy solution there

Here are some pics of the setup that went out this morning, 12S with a car type fin cooler and a ghetto "gt style" vent. It worked as the motor only came back insanely hot but not melted.

[ray schrauwen]

I love those outrunners Simon, I still have a pair bagged up for a twin cat.

Love your thread, keep up the good work!