MICRO RIGGER

[Speed Jr.]

I put a few pics of the finished boat, take a look:

https://www.intlwaters.com/gallery/displayimage...cat=10221&pos=5

It was a fun build and a learning experience about these electric helicopter motors/esc's

Larry B)

 

[anthony_marquart]

Man that is supper cool. What kind of speed do you expect. The pond in INDY would hav been perfect fro that today... Super smooth except one .12 rigger running.

 

[Ray Sametz]

Why do the sponsons look upside down. :unsure: :unsure: :unsure:

 

[RodneyPierce]

Why do the sponsons look upside down. :unsure: :unsure: :unsure:

I was thinking the exact same thing. Arent your sponsons mounted on there upside down?

 

[Speed Jr.]

Why do the sponsons look upside down. :unsure: :unsure: :unsure:

I was thinking the exact same thing. Arent your sponsons mounted on there upside down?

LOL. Nope, they are not upside down. Since the boat will be so overpowered I needed to use the sponsons as downforce. If you look closely you can see the trailing edge at the bottom of the sponsons hang off. Its my own design, kinda taken from a set of Strait Away sponsons Ive seen at Gary Preusse's house. Im hoping for about 45mph. With the RPM, ave. pitch, and 15% slip I calculate 51mph. Im curious about the RPM though with the load of the boat. should be around 36,000 rpm. Ill be happy with anything over 40. I plan to run next week as long as there is no wind.

Larry Jr.

 

[Andrewg]

Larry,

51 mph - Here's hoping. If you do get it you have to blurt it about it bigtime. It will be the fastest micro ever built by huge margin

 

[Speed Jr.]

Larry,

51 mph - Here's hoping. If you do get it you have to blurt it about it bigtime. It will be the fastest micro ever built by huge margin

Actually, thats not true at all. A few guys from RC groups that sell a new Depron Micro rigger kit are running in the 40's with a far less powerfull motor/esc, and less hydrodynamic design that Im going to try out. The technology with these electronics in the near future will allow these micro boats to go far faster than what most would believe. I honestly put 40+mph to be conservative. With correct setup and top end electronics much higher speeds can be achieved. These Lipo batteries are amazing.

Larry Jr.

ps, there are some micro riggers (about 18" long) in Brazil going over 65mph. theres just no class for them lipos to really race.

 

[AlanN]

True...no classes are setup for the microriggers...but IMPBA has allowed Lipos....in classes already established. I hope to be at lease testing some more for sprint setups this year...already been amazed by the new cells in our offshore setups.

BTW Speed...I realy like your rigger...where do you buy depron?

 

[Speed Jr.]

BTW Speed...I realy like your rigger...where do you buy depron?

My local hobby shop carries sheets of it in different thicknesses. but my local hobby shop isnt just any, its Al's Hobby Shop in Elmhurst, Illinois. You might have luck finding them at a hobby shop that carries plane stuff, thats what its primary use is for. Cost about $7 for a 3' X 4' sheet. I used about 15% of that one sheet for my complete rigger, so about $1.05 worth B) The problem is its really not worth buying to ship cause it will cost more to ship than it costs itself. Hope this helps, maybe you could find it online somewhere close to where you live.

Larry Jr.

 

[rek]

Larry,

One thing I do not think I have ever seen or heard discussed is the front to back weight ratio on a rigger, similar to putting scales under the tires on a car. It always just seemed that if it porpoised you knew the weight was to far forward. Anyone have a take on this subject.

Richard

PS. did you layer the foam on the sponsons or use a solid piece.

 

[Speed Jr.]

Larry,

One thing I do not think I have ever seen or heard discussed is the front to back weight ratio on a rigger, similar to putting scales under the tires on a car. It always just seemed that if it porpoised you knew the weight was to far forward. Anyone have a take on this subject.

Richard

PS. did you layer the foam on the sponsons or use a solid piece.

Its not front to back ratio, its what we call "center of gravity" (COG) The center of gravity has a lot to due with how the boat will handle and how it should be set up, and most importantly, how it will turn. Its important to have a turn fins trailing edge at the cent of gravity. what most call "porpoising" can be corrected at the strut most likely, but I guess there are some extreme cases where the COG is so far forward that the boat's rear end will not hook up correctly. My COG is about 1" beheind the trailing edge of the front sponsons. Should be about right. The sponsons are five 1/4"depron sheets slapped together vertically, so its very solid. I cut out, glued, and sanded sponsons, slapped the 1/64" on the bottom in about 25 minutes, done.

Larry

 

[rek]

On the turn fin. If mounted at CG, do we go with leading edge, center or trailling edge on CG. I figure a little behind of leading, in theory this should create a slight push in the turns.

Richard

 

[Speed Jr.]

On the turn fin. If mounted at CG, do we go with leading edge, center or trailling edge on CG. I figure a little behind of leading, in theory this should create a slight push in the turns.

Richard

Trailing edge is what everyone seems to recomend, but on my boat Im starting out with the COG right in the middle of the turn fin and I have room to go forward or back. Some boats like different things, plus the style of turn fin plays a huge role also. The characteristics will change with the role in the turn fin(how much bottom is bent and if its a role ir a crease) and the profile if the turn fin(is the leading and traling edge vertical or at an angle) and of course the depth. With a new boat this needs to be experimented with.

Larry.

 

[Andrewg]

Larry

I was assumming when you said speed you didnt mean momentary but capabl;e of sustaining over 100 yards in two directions

Believe GPS claims when the boat runs it against the clock over a measured distance. SAWs experience in Nth America seems to be that baots with a GPS in them always run faster. What I dont understand is why the racers take them out when theyare trying to break the real records

 

[Paul Pachmayer]

Andrew,

SAWs experience in Nth America seems to be that baots with a GPS in them always run faster. What I dont understand is why the racers take them out when theyare trying to break the real records

Some don't take them out. I love your broad sweeping statements. GPS speeds are very close to clock speeds from my personal observation at the SAWs. Within a couple miles an hour.

Paul.

 

[jayt]

SAWs experience in Nth America seems to be that baots with a GPS in them always run faster. What I dont understand is why the racers take them out when theyare trying to break the real records

I don't understand what you are trying to say Andrew. My fastest SAW records were all set with a GPS in the boats at the time.
The GPS reading is almost always within 1-2 mph of the trap speeds, unless I take a very bad line. The GPS is an excellent tool for SAW tuning as long as the racer runs the boat at full speed for at least 400 feet. My testing speeds at home with the GPS are almost always within 2-3 mph of what I achieve through the traps at SAW events with the same setup. The extra 3 ounces of the GPS doesn't seem to hurt - I took the GPS out of my 12-cell rigger and the trap speed changed by 1/4 mph - no difference.

 

[BulletMaster]

nice looking bit of construction there m8!

But quick question.....do you think the JST power connector wil be up to the challenge?

 

[Jim Caldwell]

JST'S are rated for only 10 amps. Iwould suggest 3,5 mm bullet conectors, fairly small.

 

[Speed Jr.]

Alright well I ran it today! 1st run it was running very wet with the end dragging quite a bit in the straits. Couldnt really reach any hig rpm though. So I dropped the strut and threw it out and it ran much better but still didnt lift out like I would want it too. I added some angle in the strut to get the back to lift more. As I was walking the boat down to launch I heard a noise that nobody wants to hear; pohhhh, followed by a phizzing noise. I immeadeatly ripped the tape of the hatch and a puff of smoke came out. The speed control had melted. Luckly I got to it fast enough that it didnt do any damage to anything else in the boat. I was going to take some pics on the water after getting it running better but I really didnt have much of a chance. Looks like Im off to buy a new ESC. I am happy with the design of the boat though. it does corner exteremly well, and hopefully I can get it to run a little looser with a few adjustments. If at first you dont succeed, try, try again.

Larry Jr.

 

[Andrewg]

Larry

sounds very promising - look forward to more news

Jay

I think you just gave some excellent guidlines for GPS use. The only GPS I use is the ET data logger. After using it in 1:1 and smallboats. Actually what was worrying was testing the whole setup by taking the tunnel for a high speed run while it was attached to my car. I am wary of momentary peak readings as representative of boat speed. However I havent tested on smooth water alone

I am curious about leaving the GPS in during SAW, might it be because u set the boat up for with the gps so its left there for balance or is it as a secondary reference if the run is aborted for any reason? Always curious as to the hows and whys?