Miss Geico dialed in- strut modification

[Arizonaheat]

Hi,
My son has been racing his Miss Geico (V2) in the p-limited offshore class, and we have it dialed in on stock setup with x642 prop. Batteries are just behind the front end of the motor (non-shaft side). Per the tips on the forum, I ground a wider slot in the strut, allowing a bit of negative angle. I have the strut up pretty high-- with the sponsons on the table the shaft does not touch the table-- close-- probably less than 1/8 above it (in the picture it looks like more, but that is just due to the camera angle).

In race conditions (ie, some race-induced chop in the water), the boat rides perfect, no bounce. In glass water, we get a slow bounce. I have not blueprinted the sponsons, and probably won't bother as the boat is doing great in race conditions.

Been too busy coaching my son through the races to get a video, but will try to get one next time.

Chief

How do you plan to "blueprint" the sponsons?
Is there a dimensional drawing available?

[tlandauer]

How do you plan to "blueprint" the sponsons?
Is there a dimensional drawing available?

So-called "blue printing" the sponsons is just a process to make the bottoms match each other and to make sure that they are flat when placed on a flat surface such as a glass table or granite top counter. See this thread:https://forums.offshoreelectrics.com/...ace-Prep/page2, specifically read from post #43.

[jsturess]

Longest time was bending the stuffing tube correctly and keeping the strut lined up while tightening it.

Do you taking the stuffing out or does you only bend it with hand strenght? heating?
Mine is hard as a stick (stuffing :-) )

[tlandauer]

Do you taking the stuffing out or does you only bend it with hand strenght? heating?
Mine is hard as a stick (stuffing :-) )

If you don't plan to replace the stuffing tube, you need to bend it with your hand strength, heating it on the boat will soften the FG exit point and also the epoxy, that is how people take the factory tube out BTW.
You need to take care not to kink the tube. The only portion you need to bend is where it goes into the strut, basically make it straight so you can point the prop down a bit. The suggestion is to insert the largest drill bit possible to the open end of the tube and gently shape ( bend) it.

[Speedracer128]

@ Alan

What speeds are you hitting on the gps with your setup? Also curious what kv that motor is?

[h8onit]

Just wanted to say thanks to op for the mod. It has helped my bj29 a lot with the traxxas system in it

[AlanD]

@ speed racer - it's a leopard 4082/1600. Haven't GPS'd it yet. Took it out yesterday and got pretty much the same performance out of it.

[BHChieftain]

Well my son ran his boat up on some rocks and ripped up the sponson, so that gave me an excuse to blueprint it! I used West Marine Epoxy Putty. Super strong and sands easily. I'll try to take it out on a test run next weekend before I repaint it.

Chief

[BHChieftain]

Did a test run with the Miss G's repaired and blueprinted sponsons-- wow, what a difference!! The bounce is even further reduced, but the real benefit is that the sharp edges on the back of the rear sponsons keeps the nose down much further than stock (the sponsons are pretty rounded out of the box). I did not change the strut position at all, and the nose is way down. On this run I pulled the batteries back about 1" (which would have caused blowovers previously). I think I can even reduce the negative angle I have on the current strut position a bit.

I think the only thing left causing any bounce at all on glassy water (with this config it is not a problem-- any racing induced chop lets the boat run great) is the rooster tail hitting the center mounted rudder. The next experiment will be to use an offset rudder. For sports running the center mounted rudder works great as it has equal left/right turning, but my son is racing this one in offshore class so offset should work just fine.

I've been doing free s/b of the stock props and also free strut mods on the RTRs I sell at my webiste (see sig), I think I'll add blueprinting as an option since this turned out so well. The marine epoxy putty is a bit expensive but is the perfect consistency and is super strong.

Here's a video of the run:



Chief

[lenny]

Hey.
Look like it came out pretty good,
Is mike legally blind ?
Look, It's a moving green bullseye.
I just started testing the setting on mine today,
And got some pretty good video to I think.
I will see what it looks like and than may be post it if it looks ok.

[angrycat]

hey cheif where did you buy the marine filler? i have my old bj hull awaiting carbon fiber/kevlar inlay and some sponson blueprinting after the seam split

[AlanD]

Chief, she runs pretty flat and smooth. Can you share some close up photos of the edges you're referring to?

[ray schrauwen]

I like that stuff. I wonder if I can get it in Canada??

Well my son ran his boat up on some rocks and ripped up the sponson, so that gave me an excuse to blueprint it! I used West Marine Epoxy Putty. Super strong and sands easily. I'll try to take it out on a test run next weekend before I repaint it.

Chief

[iop65]

i wonder if it would make a difference when you would make the last step 90° angle ?
now it's about 100-110°

the MG v2 iss my first cat ,so i'm not an expert on this matter but in the mono-world we make the point where the water has to "leave" the bottom of the boat razorsharp and 90°

when i was blueprinting mine i was thinking about doing that , but did not
mine has still a very small bounce on flat water

[hydro_pyro]

Same thing with full-scale performance boats. A sharp, 90° square trailing edge is ideal. The water comes off clean with less drag.

[BHChieftain]

Chief, she runs pretty flat and smooth. Can you share some close up photos of the edges you're referring to?

Here are a few more pics. I found the putty at a marine supply store that sells West Systems products.

Chief

[CHIEFY_44]

the biggest thing to do with this hull to stop the bounce is blue printing the hull, I have tried everything in the past and the biggest change was when I blueprinted the hull made all the edges to 90 deg and razor sharp, I also used a rudder offset and angle the rudder forward this helps with the bow ride height, I also use 2x4s in p, I personally cannot see the advantage of having any extra cells infront of the motor its dead weight and just slows your boat down and I am sure its this extra weight that is helping pyro's boat run flat, but how much speed is he losing carrying the extra cells. My MG runs great tlaunder has seen it running and i'm sure he will back me up on this, I run my MG in prod class with a aquqcraft 2030kv motor and the same 2x4s in p on a x442, and when i'm just messing about I put a castle 1515 1y in it with a m445 and it flies, if you can get this boat to around 50mph it just flattens out and flies. There is a video on here somewhere take the time and look for it and you will see what I mean

[hydro_pyro]

Looks can be deceiving. I'm using the same overall COG as many others who are running a pair of 3s packs. I have blown over three times using this COG. It's NOT bow-heavy. I have tried it more forward, and it tends to plow the front end at lower speeds.

The strut mod helps lift the stern, so the tunnel is not constantly trapping and "burping" air pockets out the back, which is the hallmark of catamaran porpoise in the 1:1 world.

[CHIEFY_44]

Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat, I have done that mod myself you have to to move the strut up as far as you need to and have +/- angle adjustment on the MG v1. The other thing is every hull is different, your setup might not suite my hull and vice versa, there is loads to take into consideration when setting up a boat. For me IMO carrying that much extra weight does not make sense, there again when I'm racing I want to run as light as possible

[tlandauer]

the biggest thing to do with this hull to stop the bounce is blue printing the hull, I have tried everything in the past and the biggest change was when I blueprinted the hull made all the edges to 90 deg and razor sharp, I also used a rudder offset and angle the rudder forward this helps with the bow ride height, I also use 2x4s in p, I personally cannot see the advantage of having any extra cells infront of the motor its dead weight and just slows your boat down and I am sure its this extra weight that is helping pyro's boat run flat, but how much speed is he losing carrying the extra cells. My MG runs great tlaunder has seen it running and i'm sure he will back me up on this, I run my MG in prod class with a aquqcraft 2030kv motor and the same 2x4s in p on a x442, and when i'm just messing about I put a castle 1515 1y in it with a m445 and it flies, if you can get this boat to around 50mph it just flattens out and flies. There is a video on here somewhere take the time and look for it and you will see what I mean

The first time after my blue printing the ride pad, i thought to myself, big deal, now let's see if it really makes a difference. I was speechless the moment I pulled the trigger. I have also found that dead weight infront of the motor is useless, I put a heavy 5000mAh nicad stick, the boat still bounced.
My mistake is not doing a 90* on the back of the ride pad, after seeing how great yours was running, i will go back and redo them the future.

[BHChieftain]

Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat, I have done that mod myself you have to to move the strut up as far as you need to and have +/- angle adjustment on the MG v1. The other thing is every hull is different, your setup might not suite my hull and vice versa, there is loads to take into consideration when setting up a boat. For me IMO carrying that much extra weight does not make sense, there again when I'm racing I want to run as light as possible

Hi Chiefy_44
Where in CA are you located? I'm in San Jose,

(the other ) Chief

[CHIEFY_44]

Hi chief I live in Rancho Dominguez just off the 91 fwy

[hydro_pyro]

Pyro I am NOT saying the mod doesn't work, what I am saying is the weight of the extra battery has to be slowing your boat...

If it's slowing it down, then why am I running close to 60 mph on a stock motor and ESC? The third pack is NOT for dead weight, it's a third 2s pack wired in series for 6s total. It does not run bow-heavy this way-- I have seen three blow-overs with this center of gravity, but rarely any bouncing.

When I run 4s (two packs), I put the side packs slightly more forward and it still runs nicely, with a high-flying bow, and no bounce.

6s:


4s:


If anybody is wondering... I made the pair of spacers in the photo from thick commercial rubber roof sheeting. Each one is a rectangle of flat rubber with the motor wires threaded through three tight holes. This keeps the stock motor bullets cooler, and keeps them from making contact with anything if the heat shrink gets hot enough to soften. Works great.

[BHChieftain]

Here's another video from a run we did yesterday-- since blueprinting brought the nose down I was able to set the strut completely neutral, no negative angle. The bottom of the propshaft is even with the sponsons (just put the boat on a flat table, and set the strut so everything was level). So bottom line-- if you blueprint with 90 angle off the sponson, you could skip the strut mod altogether.



Chief

[iop65]

runs great!
hope to achieve the same !

[maxmekker]

Yeah that was super to watch, great Place to run to. Love those Places were you get a bitt above water Level.

[skeeler]

Very informative thread. Subscribed.

[BHChieftain]

I'm pretty sure that's all high-quality aluminum, but I could be wrong. Aluminum tends to wrap itself around the Dremel bit, clog up the abrasive surface, and sort of "burn" away while you're grinding... This can make it more difficult than some other materials.

I used a spiral-fluted metal cutter bit, and finished with a small stone bit.

Hi,
I made this mod for a few customers and this time used a rattail file to widen the strut slot-- much easier than the dremel.

Chief

Sent from my XT890 using Tapatalk 2

[Speedracer128]

I can't see a link to video. But that is impressive to have am MG near 60 with stock motor.

[BHChieftain]

I have a Word doc that has both Miss Geico and Blackjack mods and setup I have made documented, and also has a great overview on prop selection. I have not yet updated it with the blueprinting process, but I will get around to it this winter.
If anyone would like a copy of it, please email me at jqhydro@gmail.com

Chief