Simon O
Don't let some one chase you off just because they have some nitro boats and a Vette
That does not make them an expert on set up and weights for electric
I have been following your builds for some time and they always turn out in the end

Not trying to chase anyone off TRX needs all opinions.. riggers react to the same adjustments no matter if they are nitro,electric,turbine or whatever pushes them around the pond.
I realy dont think an electric rigger has its own set of rules with the obviouse exception of power...you still have to deal with the same hydrodynamics any other rigger has to deal with.. Dont you think?? am I just totaly out in left field about that???
The biggest differance I see is weight..electrics are much lighter and therefor do need to have the cg set differantly and components placed in the hull differantly..other than that whats the differance????and I dont think ive given him any advice on weight other than to save it anywhere he can..all ive tried to help him do is get his hull into a bit better running shape..sounds like he is getting there and that folks is what its all about.

And TRX the ebay store you need to go to is Head of the river-rc specialist....jhocheung....hope this helps

My electrics are significantly heavier than my nitros.

The difference is very clear. Inboard hydro's and outboard hydros are completely different. Outboard Hydro's use oversized rear sonsons to support all that weight hanging off of the hull. The CofG is no where near where it should be in this case for any hydro. OB Hydros CofG is further back then it should be but this is unavoidable. Having a CofG so far back requires the use of very large rear sponsons.

Outboard Hydro's typically don't use high lift props which would aid in the amount of lift produced, thus relying on the sponsons for additional lift. These style Hydro's also do not handle as well as in inboard. This is due to the draggy rear sponsons being so large and carrying a lot of weight, and that the CofG is not spot on the turn fin.

Ryan

Ryan did a good job of describing the differences....srw1960 not so much...
I currently have a brushless Predator Rigger that started off with ride pads but I quickly found that they just added unnecessary weight and drag in the rear end and took them off right away.The boat is much quicker now and is just a better all around boat for it.

Steve

No ride pads on this boat and it's faster than nitro's

Just picked up a new prop Octura Y-535, hopefully this one won't explode on me. http://www.offshoreelectrics.com/products.php?cat=97 Do I need to sharpen or polish this or something, I never owned one of these props before?

You must have bought a raw prop as they are out of the S/B props for that size. So I think I am safe in assuming that it needs to be sharpened and balanced. If you do not have the equipment to do this yourself I would be glad to do it for you. Send me a PM and I will give you a delivery time and cost.

My first run with my new Octura Y535, I made some new rear sponsons because I think I needed some more lift before the prop upgrade. I think I need to take off the rear sponsons because it looks like it has to much drag still. Just give me some opinions of what you guys think I should do. Thanks, Chris


http://www.youtube.com/watch?v=5dopsUhrTwU

Show us a pic of what you added please and maybee we can see what the drag issue is..if they dont have a very sharp front edge they will def slow things up...and definatly get the prop sharpened and balanced..theres a thread in general boats or maybee speed nitro that will show you how to do it yourself or take egneg up on his kind offer....

Ryan you said your electrics are significantly heavier? than your nitro's??I would have expected the oposite...if so and im not doubting what you said I agree with all of it by the way. there is a distinct balance differance from O/B to I/B and yes a coresponding differance in rear sponson shape and size and I totaly agree an O/B rigger will not be competitive..comes down to weight and drag doesnt it??? anyway why are the electric riggers running so good with no rear sponson or ride pad if they are heavier??? doesnt make sense to me..you would have to move everything far forward to get descent lift off the back and that should weight the nose down to bad..or are the front sponsons on the electrics oversized to compensate?? all i have seen seem to be pretty large front sponsons....enlighten me please?

Egneg are you running a high lift prop on it? nice boat by the way love the color

On my 2s1p rigger, my lightest electric setup most comparable to my old .18 powered rigger- weighs 3lbs 2oz. Weight at the prop is 4oz. The prop has to lift 4oz of weight in order to lift the rear up. That is due to c of g placement. The strut is a flat bottom hydro which also aids in lift.

I custom build or setup my riggers so that the battery packs CofG is placed ahead of the Cof G for the boat. This means a heavier pack will bring the hulls CofG closer to the front.

In order from front to rear placement of the electrics is as follows
Batteries
ESC
Motor
Radio/Servo

On the nitros I set them up as
Fuel Tank
Engine
Radio.

When the tank was empty CofG would change rearward. The pipe/motor/radio equipment would weigh the hull down in the rear also effecting CofG. Not sure how they currenly setup nitro riggers but thats how mine were setup.

Just for reference my old .21 rigger weight around 4lb 7oz with fuel. My current 4s rigger will weigh in around 7-8lb. Still in building stages but these are the realistic weight goals. A well setup .21 should do close to 70mph. My 4s hull should be able to exceed 70mph.

Ryan

Not at the moment ... I have an M545 on it as all the weight is up front to keep it on the water. Thanks for the comp on the boat.

Ok you are doing exactly what I thought you were doing to get these to run like they are and as I thought about it Ifinaly had to admit my thinking on the battery packs as being lighter than the nitro engine and fuel was wrong...I understand better now how your getting the back end up without ride pads or even sponsons...I still think a simple small ride pad with the strut coming out of it his little rigger would fly and do away totaly with the rear sponsons..anyway thanks ryan for the info

Thanks guys for all your help, I gave up on that rigger and have almost finished my new Predator. The reason I gave up was because that boat had a major leaking problem and I didn't follow any plans when I built it so nothing was even. But my new predator is coming out great and I hope I can make it fly!!


Thanks, Chris

The water conditions were great today. I had one of my best runs ever!

What setup you running in that?

Ryan

Do you think I need to make rear sponsons on my 20" Predator Rigger. I have a Feigao 540 10s, 90A Seaking ESC, 3s 3300mah 25c lipo, and an Octura Y535 Prop.

Thanks, Chris

Run it as is first.

Ryan

ok I will. And what do you use to seal the wood before you paint it?

2 Part epoxy. Use a heat gun to thin it out and then spread it. My creative tool for spreading is a posicle stick.

Ryan

Can I thin it out to the consistancy of paint and spread it with a paint brush? and also would 15min epoxy be ok to thin out?

It has a Feigao 8XL-modified, Turnigy 100a plush (water cooled) ESC, Elite 4S 35C 5000 mah lipo, .062 wire drive, speedmaster 3/16 strut and rudder, and a Octura M545-modified prop.

What is your AUW?

Ryan