new rigger build pics VIDEO ADDED

[anthony_marquart]

Video added!!!1

This is the latest revision to my .21 rigger design... It's looking real nice to me... The kit is available from Kevin Visconti if anyone would like to build one.. this is direct from the Kevin at the cost of laser and wood only.. It's JAE based,.. a few little changes here and there.. This one has a more narrow and a touch shorter ski to help with rough water hoppyness, tapered tub. It's built up with skins and doublers with notches for bulkhead.. makes assembly easy. Nice big isolated engine mounts to the tub sides this time instead of the JAE style. Over hangs on the sponsons, tub and ski,.. no curved surface touching water. Lighter build up with thinner skins and lots of triangle for structure where it's needed. Options for transom or tub side rudder mount,...

Thoughts and suggestions please.

 

[Chris Wood]

its a little late now but i would have moved the rear tube forward.. if you need to make sponsons tube adj it is going to be a PAIN with the pipe in the way.. the tube is in the way of the turn fin also.

chris

 

[anthony_marquart]

I did that on purpose Chis. I like the load of the turn fin going directly to the boom tube and directly to the CG of the boat.. This eliminates the moment arm of the turn fin to the boom tube and reduces the pull force on the sponson insert. This helps with the issue of sponson inserts coming out, and just reduces torque through the hull in general... . Unfortunately the boom doesn't really go straight to the CG of the tub,.. but it's closer than most.

 

[Jeff Barnhart]

What you did will actually make it easier for the sponson insert to pull out. Drill a hole in a piece of plywood and slide a tube through it. Pull directly up on the tube and feel how easily it slides out of the hole. Then do the same thing again only try to pull the tube out of the hole at an angle and you will see what I'm talking about.

However, the bottom line is attaching the boom tubes to the sponson with the brass insert is a horrible design that does not work well. Brass to wood makes a very poor glue hinge compared to a carbon-wood glue hinge. If you don't want your booms to fall apart, drill the boom tube hole all the way through the other side of the sponson and glue the carbon boom into the hole. Then use the SGX style boom tubes. Move the hole forward of the skid fin where it belongs and you will find that life is much easier with it there.

The forces on the boat in the turn will act on the CG regardless of where your boom tube is, the main thing is to have a rigid connection between the boom, sponson, and tub so it does not flop around. The boat going through a turn is the same as throwing an object through the air with rotation. IT WILL ROTATE ABOUT THE CG!

 

[RodneyPierce]

Jeff, he actually doesnt have brass inserts in the sponsons. I made him some 6061 aluminum pins with .040 relief's cut in them, then glued in the sponsons. So its a much stronger pin/attachment then the brass tubing....

I personally like this idea honestly. But its yet to be tested, so I will be interested to see how it works.

 

[Jeff Barnhart]

That still won't be as strong of glue hinge as carbon to wood. Unless he drills the hole all the way through the side other side of the sponson he will find that it is flopping around and loose after a few runs. The foam simply does not support the boom enough. The other problem with the insert design is that it puts all of the load on a small part of the boom tube. With the telescoping SGX booms, the load is dispersed over a larger portion of the boom tube, which is a lot less pressure on a given point of the boom.

 

[RodneyPierce]

The blackbird boats, both G1 and G2 seem to be holding up to it just fine...

 

[anthony_marquart]

Well we all have our opinions. THe inserts are notched all the way down,.. glued into Dyvinacell foam with expanding adhesive. A larger surface to disperse load may be better. I've had CF inserts pull out too,.. but the turn fin was far from the boom. My concepts are based on basic engineering principals that are proven. To me there is no doubt that there is a torque load multipled by the distance between the turn fin and the boom tube,.. and then to the CG of the boat. I can do a simple FEA that will prove this. I believe the boat rotation point is at the turn fin, and the CG rotates around the fixed point. Of course it's not actually fixed, but the point where the load eminates.

Of course I could be totally wrong,.. but I'm confident I will prove this out in about 2 weeks. I'll try to post video

 

[Jeff Barnhart]

I'm assuming the blackbirds have more to the inside of them than just foam supporting the booms. If there is more to the inside of the sponson than just foam supporting the boom it might not be an issue. I just know the JAE's don't come with anything other than foam on the inside, that's why I brought it up.

 

[anthony_marquart]

I'm not sure but I think CHris puts a block of hard wood on the boom tube insert...

 

[anthony_marquart]

starting to understand why most people don't share new concepts or ideas until they are totally proven out. TOok people a long to believe that you didn't need a dihedral or non-trp,.. and you could have overhangs on sponsons and trip...

 

[Jeff Barnhart]

ok

 

[Mike Larson]

Anthony... build it... learn, maybe.... The fin deal will be OK. After cracking tubes on my JAE's and it's always at the fin rear tube, at the tub, i think, installing the pressure/evening out the pressure with the style you have designed will help.... yeah, maybe you'll have to install the fin forward more upon testing, simple deal, make a pair of holes rearward on the fin,( boom), and have at it..... build it. We'll await results, and good luck. Mike

 

[Chris Wood]

I'm not sure but I think CHris puts a block of hard wood on the boom tube insert...

you are correct and the sponsons are made of balsa

chris

 

[steve wood]

once we got the g2 right(about 4 tubs,and 3 or 4 sponson mods) the right rear tube broke inside of the sponson,in a corner.at that time there was no hardwood insert glued in the balsa core,and the balsa actually broke.we then started gluing in a hardwood dowel insert,and gluing the aluminum insert in that. the aluminum insert has about 8 grooves turned in it and 2 cross holes.haven't had an issue since we did that.

 

[John Hudson]

Where did you get your fuel tank from? I cannot find any tank to fit in my jae 21.

 

[anthony_marquart]

That would be correct on the tank,.. And,.. I cannot say enough about walt or his product... A+

 

[kcvnd]

Tony please check your email it is regarding the stand. Thanks Kevin

 

[giuseppe gallegra]

Hello Anthony,

i have to see in the photos of you rigger that you use one 'motor mount' with light blue rubber and with nylon bolts.

Please,let me know the brand, or where i can take this light blue rubber.

Thanks and Regards

Giuseppe - Italy

 

[RodneyPierce]

Giuseppe, those are just some grommets from mcmaster carr. I will let Tony get you a link. I made the motor mount rails for him. he still needs to add a couple spacers in between the grommet and the mount rails yet.