New riggers everywhere ......

[forresterace]

Hey Guys

For all of you who are interested in riggers, it would surely be worth your while to check out the many interesting threads on the General Boating (nitro) forum. There is a groundswell of development going on using the .12 size glow engine and everyone and their uncle seems to be designing and building a new rigger for them. This size boat has a lot of relevance to electric use too. There is a huge amount of original and very creative thinking happening out there and one of the big advantages of hanging out on this board is that it's all here for us to read too.

 

[Hammerhead]

Any of you all wanna try to make an electric heat racer out of our Hammerhead .12. You are more than welcome.

One condition, though. You have to tell us how you did it, and how everything went.

Hammer

 

[forresterace]

;D

 

[Paul]

Hello Guys,

Any of you all wanna try to make an electric heat racer out of our Hammerhead .12. You are more than welcome.

LOL, Phil Thomas is still waiting to see how I made a Super Sport 45 run on electric.

Paul.

 

[TomMoorehouse]

i'm having fun with my .12!

 

[Ron Olson]

It seems that the electric and .12 powered boats are a lot alike. We share the same hardware and most of them can be made to run well either way easily! I have a mono that was an electric racers first attempt at a nitro boat after he made up engine rails for it. After some minor tweaks, it runs and handles well.

Are you going to the race in Lansing this year? It will be the first electric race that I am going to.

 

[Grimracer]

Gang

Seems to me that there is a huge difference between FE riggers and glow riggers. This is forward sponson placement..

My E-ninja is designed like a glow boat and my good friend Paul did some mods and got one to run well with the change? This is still a mystery to me and i need to drive a FE rigger that has the changes. Despite this my FE-rigger the E-ninja rockets around the pond at 40mph on a 19 turn motor and 8 cells.. What are we looking for with the sponson changes?

Paul

Crowbar

Anybody

After spending hours trying to understand the reasoning behind the change....Im toast..

Why is the sponson placement (not just the CG) different between a Nitro boat and a FE unit? Seems to me it could be that most FE riggers that have run in the last few years do so mostly on low lift props.. Not saying that the (SAW) record boats do this just a general observation.

Grimracer

 

[Dennis Whitt]

Hi Grim,I know that we run a little steaper angle in our FE riggers,My understanding of sponson placement is relative to the after plain in gaining a smooth ride through the corners.

We also have the luxuary of having a boat that weighs the same at the end of a heat as it did when it started so the cg remains the same.No fuel tank!

 

[madalaskan]

Dennis is absolutely right the after plane is critical to how a rigger will run through the corners. The key to getting a good running fast electric rigger is hitting the sweet spot with CG, after plane, and angle of attack all married up making a well balanced rigger. All of these variables change with cell count. Not so major of changes with a 6 cell boat to an 8 cell boat but significant when you go to 12, 18, or 24. Generally speaking the same boat will run well with 6 or 8 cells likewise with 12 or 18 cells but trying to run a boat that has a 6 cell configuration on 12 cells does not work well.

 

[Grimracer]

Guys

Understand.. however i can not imagine that my US-1 Nitro Ninja 21 could benefit from these changes. If i were to place the sponons in a forward position the boat would take more weight to correct things. This does not make sense to me. As for sponson AOA i have tried them all and anything running more then 3.5deg at 70 mph (heat speeds) gets ugly in a big hurry.

O yea you have to see this thing turn...lol..13 sec laps are not that uncommon.

I just trying to imagine how my glow ninja would run with a low lifting prop and the sponsons in the forward position.... Lots of prop blow out? Lots of speed loss in the corners? Im just not sure.

On an FE rigger… where do you guys place the turn fin in relationship to the CG? On mine (both FE and Glow) it is at the trailing edge of the turn fin. Seems to me im not seeing this in the photos that are out there.

Grim

 

[Dennis Whitt]

I agree with Larry, Finding the sweet spot all in the same spot! has been my nemesis.

On the lower powered riggers I tend to run the cg farther forward as to move weight farther over the sponsons.

In my experience I have only been able to ball park the cg and then tune it in according to power and prop.For me it would be hard just to say well your cg should be at this point.were is Dick when we need him...Ooops probably on a diaper changing challenge!!! hehehehe!

 

[Paul]

Hello Mike,

Man, I've got to get the boat in your hands. Once you run my new 8 cell boat you'll load your shorts. This thing flat out rips. And I've got the big boat coming back as well, that one was turning mid 70s on 16 cells. Oh ya, that was an oval boat, not a saw boat.

Paul.

 

[crowebar]

Hey Mike,

I set the CG up the same as you. It's right at the trailing edge of the turnfin. However, the trailing edge of my turnfin is 4 inches behind the back of the sponson.

Hey, you may be right and I may be wrong or we both may be right. I'll bet I could set your boat up to run good and visa versa. Where I notice a difference with forward sponson placement is overall handling.

To me, my boats are more streched out. As long as you have the power to hold the tail up without adding a bunch of strut angle then forward sponson placement should benefit stability. My guess is if I tried to set up your boat my way I'd have a hard time getting the tail to settle onto the prop all the way around the course.

Remember too, an electric boat has TONS more toque then a nitro, especially a .12. Most of the power on an electric boat is at start up. It's one of the reasons I don't put rear shoes on the back of my smaller boats. I just don't need them. I'll bet my boat wouldn't be all that hot with a .12 nitro motor, it would really struggle to get on step. Then again?????

My goal is to have a boat run just like a hydro and be as stable as possible. A longer wider stance should take care of the stability but it has to be constrained by the available power. The marrige of these two components has been the key for me.

BTW, I can remember talking with Paul about modifieng his e-ninja. I think he sent me pics the next day with the trick he did to the sponsons. He's an inovative guy.

Someday we'll have to hook up and see how everything pans out on the course. maybe my 6 cell rigger vs. your .12. However, I think I'd get destroyed if you're running 13 second laps on a nitro course. I can run 10+ second laps on an electric course. Mybe I could squeeze a few more cells in!!!!!

Dick

 

[Eric Perez]

I noticed no one has mentioned another major difference between the .12 and the 6-8 cell riggers. The boats may be similar in size -but there is a 1/2 pound difference between them.

How do you work arround the weight difference between a 2lb. .12 Rigger and a 3lb. 8 cell rigger? What is the std. weight of a competitive 6 and 8 cell rigger?

Also, with electrics you can move the CG to other areas... With forward battery placement you can get the CG quite close to the running surfaces. On the .12 nitros there is only so much you can do for moving things arround.

I would like for someone to explain what the benefits are of CG that 2" from the trailing edge of the spoon to one that is 4".

 

[crowebar]

Hi Eric,

You're right about the weight. The bigger pictures is it's very hard to compare nitro and electric and even fewer people qualified to do such a comparrison. My guess is I could make and electric better then Mike or many other nitro guys. On the flip side, I wouldn't even begin to compare myself to any of these guys when it comes to building a hot nitro boat. I'm sure there is someone out there that could, but I can't. My .15 is a dog comparred to my 6 cell rigger. that's why I think it would be fun to do a run off sometime.

The Striaghtline record for 6 cells is 58, but I think the 60's are very possible. The straightline record for 8 cells is 70 MPH. By no means do oval speeds com close to this mark, but it might be a starting point for comparrison. I don't know of many others.

Regarding the CG at 2 inches vs 4 inches. As I mentioned in my last post, it's for stability. My boat (and I emphasize "my") settles out better in oval trim at 4 inches. It's fast down the straights and looks like it's on a string around the corners even in race water. In boats where I've had where the CG is farther forward, the boat hops and bucks a little more in race water. It will eventually settle down, but it seems to get put out of shape a little easier then boats with the CG at 4 inches. This might not work on a boat with a .12 as it may put too much load on the prop.

Hope this helps,

Dick

 

[TomMoorehouse]

yea id say your right Dick, the cg being more towards the front for nitro does help to unload the prop. the other thing it does is help keep the boat on the water. if it is to far towards the back it is more prone to blowing off.

here is something Gene Gillman and i noticed however. with .12's we are getting them very light. especially with our saw boats. we both quickly learned that you cant launch them with as much throttle as you would a .21. they will actually do a wheelie on the launch if you give it too much throttle.

I guess on electric this is not as much an issue as you can launch them from a dead stop. But with everyone that is talking about 12's on the forum saying they have problems with hopping i wonder if we would benefit from a more rearward CG. so what i'm saying is with very light boats, and the new high power 12 engines this might be a good idea to try for this size class.

what ya think guys?

 

[crowebar]

Sounds like a nice idea to me. If it doesn't work you'll have a heck of an electric boat! Before the advent of the brushless motors I ran the CG's much farther forward. There just wasn't enough power to keep the tail up.

Blowoffs aren't much of a problem with electric riggers. It still happens, but the weight of the batteries keep it pined down pretty good. What would happen to your boat if you dropped a pound of lead up front?

BTW, what kinds of speeds are you getting these days?

Dick

 

[TomMoorehouse]

well unfortunately my saw 12 never got a timed pass so i have no idea what it did. bad weather and rudder problems..... then the club lost the pond so i could not even do it last year.

my newest 12 ive had out only once and it went 47 with a prather 215 on radar. it was hopping real bad with the v937. i really want to try the 2137 or v940 if i can get rid of the hopping.

 

[Randy Naylor]

I got my small nitro pond back. it has been two years sence I had a place to run the small nitro riggers. You all with the talk about .12 gets me going with thoughts for the new ABS sponsons and nitro .12 to .15. Anyway I have enjoyed the thread.

Randy