CF Rigger Build

[Meniscus]

OK, I'm finally getting around to my rigger build.

I picked up these sponsons:

CF_Sponsons.jpg

I have some Carbon Fiber sitting around and am considering using it for this build. I'm also considering creating CF rails much like the Graupner that Diego recently acquired.

Scenario: Rigger will be just shy of 20" in the 50s range, maybe up to 60. I think I have the power system worked out for this, but still crunching the numbers.

First a few questions for the rigger guys: At these speeds, how important is tub design? Should I opt for a sweeping wedge type or something more aggressive? More specifically, I am assuming that at these speeds, aero will be more important. With this in mind, where on the tub should the crest or maximum height be (after which there will be lift created)? Please note that this is an ultralight build and a kevlar type material may be used to skin foam for the tub. Last question is, how much angle should be under the nose? I know that it will not come in contact with the water at all when at speed, so how much lift should be created there which in turn would lift the sponsons out of the water, if any?

So here is my dilemma regarding attaching the sponsons: I have the concern that I may not get the angle just right for the wet ride sections and I may have to adjust. Other than the Xzess adjustable and the Graupner rigger, what other adjustable designs has everyone else seen?

My thought is, if I run a tube through the nose and then run the front boom through it, then that portion could easily move and the back part of the sponson would be supported (and adjustable) using the CF straight edges (rails) to the back of the rigger (much like the Graupner rigger).

Anyone care to weigh in? Meanwhile, I'll get some better pictures of the sponsons and see what I can do about drawings (digital camera is MIA at the moment, LOL).

[Fluid]

My record setting 4-cell (NiMH) riggers ran in the mid 50s and were 19-22" long. Believe me the longer ones worked better at these speeds. With modern BL/LiPo power you do not need a lifting tub, and streamlining is not critically important at 50-60 mph. You are operating in ground effect and normal "airplane" aerodynamics don't always apply. Using a "wing" tub shape is useful only to fit in larger components without building a bulging cabin. Don't even worry about where the "hump" should be, this isn't what causes useful lift.

What power are you intending to use? If 2S and 540-sized motors are planned then 20" is too short by far....24"-27" would be a better target. If you are using a small-format 380 motor then the smaller hull size is more important. The question then becomes - can you achieve 60 mph with the 380 motor?

What are your goals for the build? What run times are you expecting? Where will you run this small boat? Have you run a 60 mph model before? These questions should be answered before you go much further in the build or you may end up disappointed.


.

[Meniscus]

I know that I will be pushing it to achieve those speeds. I'm not denying that.

Goals for the build: Low 50s, mainly sport setup, not SAW setup but only limited turning, runtimes 3-4 minutes if that.

Why isn't the 20" going to work? The sponsons will likely stick out and add an additional few inches. Hardware will add another 1.5" or so. So I'm thinking the overall length may be around 23" or so, but not sure yet.

Setup will be on 3s lipo, so far as the motor etc., I don't have it in front of me to share that info.

[Meniscus]

ESC will be the SeaKing 60a.

Any other thoughts on adjustable sponson mounts?

[Meniscus]

no one?

[longballlumber]

Adjustable in what direction and how? Most riggers I have seen keep the rear boom adjustable to change the AOA using shim stock under the boom tube mounts.

[Meniscus]

Adjustable in what direction and how? Most riggers I have seen keep the rear boom adjustable to change the AOA using shim stock under the boom tube mounts.

Adjustable angle of the sponsons in reference to the degree on plane. Could you explain the shims under the boom tube mounts? Forgive me, I don't get it.

I know a lot of the gassers have adjustable riggers, but they tend to run wet into the tub and of course, I'd like to be able to adjust the angle without introducing water into the tub.

Thanks for the feedback and questions for clarity.

[Meniscus]

My record setting 4-cell (NiMH) riggers ran in the mid 50s and were 19-22" long. Believe me the longer ones worked better at these speeds. With modern BL/LiPo power you do not need a lifting tub, and streamlining is not critically important at 50-60 mph. You are operating in ground effect and normal "airplane" aerodynamics don't always apply. Using a "wing" tub shape is useful only to fit in larger components without building a bulging cabin. Don't even worry about where the "hump" should be, this isn't what causes useful lift.

What power are you intending to use? If 2S and 540-sized motors are planned then 20" is too short by far....24"-27" would be a better target. If you are using a small-format 380 motor then the smaller hull size is more important. The question then becomes - can you achieve 60 mph with the 380 motor?

What are your goals for the build? What run times are you expecting? Where will you run this small boat? Have you run a 60 mph model before? These questions should be answered before you go much further in the build or you may end up disappointed.


.

What motors might you suggest? Of course I don't have the disposable income right now for the really expensive stuff, but would still like to know for future reference.

Thanks.

[Dr. Jet]

What motors might you suggest? Of course I don't have the disposable income right now for the really expensive stuff, but would still like to know for future reference.

Thanks.

If you are looking at "380-sized" motors, I have had good success with the Neu 1107/1.5Y/H. 3400 Kv, fan-cooled. I can direct you to a source for these motors at $80 (plus S&H). He only has a few left at that price. He may also have a 1107/2Y/H which may be a better option on 3S.

[Meniscus]

I am considering the Ammo 28-35-5100 if I still go with the 3s 11.1 (still crunching numbers)

Otherwise, I may use an Ammo 28-45-2700 at 4s 14.8

However, I may entertain another option, only thing is, I'm not sure I can come up with the money for the Neu motor to make this happen, especially since I've got some other projects that need attention too.

I'm still open to all ideas though! I may have to sell something, but I'll make it happen!

[Meniscus]

One soul for sale (or trade).

LOL, J/K

(Also taking donations) Again, J/K

[Dr. Jet]

I grabbed a few of the little NeuMotors from my source when he was having his "Giant Blow-Out Sale". What have you got to trade (besides your soul - I already have enough of that)?

[Dr. Jet]

Correction (for you number-crunchers): The -2Y NeuMotor has a Kv of 3400 rpm/V. The -1.5Y is 3850 rpm/V.

[Meniscus]

Trade? I'd love to, but I don't have much available and certainly don't want to insult you. I've been giving away some of my stuff available for trade to a newbie to our club, Jeff. He purchased a Miss Vegas, Nitro and we're trying to get him to go full Electric!

So now that you have the disclaimer regarding insult, LOL...

• I have an Ammo 28-45-2700 that is used, but in good shape (used to be Diegoboy's). This motor was originally slated for this rigger, but as time goes on, and since I don't have a 4s lipo, I'm thinking about a different motor.
• I have one of those NQD PX-16 32" ABS catamarans that has the electronics removed, but in a plastic bag (plus the BS transmitter). One of the brushed motors is bad. Other than that, hull is virgin, minus a sticker or two. I have hopes to do something with that since it was a gift from a family member. I'm not sure where I'm going with that one.
• I also have a small Turnigy brushless motor I tried in the Renegade (can't think of specifics right off hand, but it may be 2300kv, or maybe 2500kv?).
• Last I have a no name brushless motor that is 4300kv and in good shape (it may have come from hobbycity, not sure). Its gold in color, finned.

Other than that, I don't have much. I'm currently running a BJ26BL (still on NiMH), the resurrected Renegade (destined for the club's next newbie that needs a boat to run).

So, the point is, I appreciate the offer, but don't feel like I have anything worth trading. Especially to someone such as yourself LOL! I figure you have this much stuff sitting in a box in the corner you haven't looked at in 5+ years!

Go ahead, fess up, the truth will serve you better than diverting the subject!

[Meniscus]

Hey what do you mean:

your soul - I already have enough of that

LOL! For the record, my soul is in my boats and no where else.