Miss Geico 17 brushless conversion / planer board / trim tab on rudder set up?

[Davey80]

So I picked up a few MG17's for summer time pool racing, as well as brushless set-ups for each. I've been digging through the forums on here, as well as just about every YT video I could find on it. There is one video in particular, posted by Waggers79 a few years back, that shows very nice performance from this little hull. Here's the link:

https://www.youtube.com/watch?v=AQx9OfQ1-xg

I'd like to replicate that. He did it by counteracting the direct drive angle using a (planer board?) trim tab on or near the rudder. I'm looking for info available on parts to use, pics of what's entailed, and/or how to go about fabricating it.

Here's a quote taken from his video comments on what he did: "Next part is very important; the pitch of the drive shaft was designed to put the prop at a particular angle for the cat to plane out on the water with the stock motor. With the power increase the boat will nose dive and flip...The best solution I found was on another video on here....fit a trim tab to the bottom of the rudder (easier than it sounds) thus driving water pressure from the prop down onto it which will drive the nose up and allow her to plane out...."

Any personal experience you guys have with this would be very helpful, thanks! -Mark

[fweasel]

PM member H&YRACING. He had one at a pool event in Indy this year and it ran great in smooth water. Perhaps he can send you some pictures of his. It was totally custom and rebuilt with scaled down hardware like you would use on a traditional FE cat hull. New stuffing tube with a bend, strut, offset rudder, and a brushless motor. There were no trim tabs on that boat and it certainly wasn't nose diving.

[Dr. Jet]

I would cut the straight shaft housing off the bottom of the hull, fill it in, and consider using this strut/rudder with an appropriately installed and curved stuffing tube: https://www.offshoreelectrics.com/pr...prod=ose-80972. That particular unit has a limited strut height adjustment and may or may not work with your hull. I put one on my 16" scratch-built cat (not yet completed) and had to modify the transom to get the prop in the right location. Another alternative would be to use the Octura strudder assembly. Here's a photo of the Octura unit on a 17" brushless cat I had a decade or so ago. It was an order of magnitude faster than the one in the video you provided, but due to other design factors, it didn't corner very well at the speeds it could obtain.

[H&YRACING]

PM member H&YRACING. He had one at a pool event in Indy this year and it ran great in smooth water.




Thanks fweasel,
I was delighted by the performance of such a small hull. As you said its setup like a full size hull. Most of the hardware is hand made. Simple but strong.

Points of interest:
1. The Plastic strut was removed carefully using a sharp knife and gently persuading it out.
2. motor mounted further back to allow more room and better balance.
3. Servo mount is mounted in right sponson. This frees space and makes great alignment with rudder.
4. Inner plastic lip around lid opening is trimmed extra close to create room for sliding batteries and ESC in position.
5. All old mounting holes (10) were plugged with plastic white plugs and glued in place. This included moving the water cooling exit to port side.
6. The entire drive line is the same as a larger one. Brass stuffing tube, .096 flex cable & drive dog.
7. Rudder is stainless steel with water pick up attached to back. Homemade steering arm from aluminum.
8. Bottom sanded flat (blueprinted). The bottom picture showing the white areas where the green was sanded.

If I was better I'd attach the the video of it running in the pool this past January. It's over powered with a 3600 kv motor and 3S battery. On its first run I was surprised how stable it was in the turns. I'm not sure how fast it is, but I wouldn't shy away from any challenge. Looking forward for someone to run it in our "mini" class this year.

Mike

[H&YRACING]

More Pics.

[Davey80]

Miss Geico 17 brushless conversion / planer board / trim tab on rudder set up?

Lots of great info, thanks guys, much appreciated. [emoji1303]

I’m pretty limited on what I can tackle right now due to being overseas for work and not having access to certain tools and parts.

I’m trying to focus for starters on improvements I can make to get these boats decently operational on 2 or 3s here at the pool without getting in over my head on modifications.

If I can get the right parts though, I guess I might take a stab at the driveline.

With regards to the flex cable, are they available in a pre cut size that works well for this hull or do they have to be custom fitted?


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[H&YRACING]

With regards to the flex cable, are they available in a pre cut size that works well for this hull or do they have to be custom fitted?

Unfortunately there are not and yes the brass stuffing tube and shaft have to be custom fitted. I'd say converting the drive line over would have the single biggest impact.

[Davey80]

Miss Geico 17 brushless conversion / planer board / trim tab on rudder set up?

Unfortunately there are not and yes the brass stuffing tube and shaft have to be custom fitted. I'd say converting the drive line over would have the single biggest impact.

Rgr, thanks. I will see what I can do with the stock driveline and new electronics, and go from there. Maybe in the interim I can figure out Waggers79’s rudder/trim tab mod, use that while abroad, and then make the switch to a flex cable when back home.


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[trigger]

The aluminum parts on the boat as seen in the pictures are very nice. If you don’t have those skills a GP1 strut and rudder system would get you very close, but those will be plastic....... you could even use the wire drive from the GP1 too and the collet. Again it won’t be to the same standard, but it will be a major improvement over the stock boat. That brushed system is a bit of a turd.

Sorry to interject Mike. I know that thing is a rocket, just a few ideas, if tools are limited.

[Davey80]

The aluminum parts on the boat as seen in the pictures are very nice. If you don’t have those skills a GP1 strut and rudder system would get you very close, but those will be plastic....... you could even use the wire drive from the GP1 too and the collet. Again it won’t be to the same standard, but it will be a major improvement over the stock boat. That brushed system is a bit of a turd.

Sorry to interject Mike. I know that thing is a rocket, just a few ideas, if tools are limited.

Thanks for the idea. That seems promising. I'm gonna order one set of the GP-1 drive line components for starters and see how it goes. I messaged AQ CS to get the specs on the wire drive and stuffing tube. Waiting to see how intact Hobbico CS is these days with all that is going on.

I also ordered some small stainless trim tabs to attempt the YT Waggers79 rudder/board mod. We'll see how that goes. Mail takes roughly a month to get here, so this might take awhile.

[wingnut]

Sounds like the tab on the rudder is more like a hydrofoil

[Davey80]

Sounds like the tab on the rudder is more like a hydrofoil

Yep, pretty much

Quick update: The first boat just arrived in the mail yesterday along with a bunch of upgrades. I got a box from OSE today with all the Leopard motors and cooling jackets. On top of that, I just found the YT video that was referenced in the initial quote, about attaching a trim tab to the rudder. It looks pretty straightforward. Will post up pics and the specs on the upgrades as progress is made. Still waiting on new couplers, batteries, and some other goodies which is gonna take a few more weeks.

Pretty sure this is the video referenced in the YT post: https://www.youtube.com/watch?v=Ds7TrI7_84Y

[jtthebiggafigga]

Hi there, I would like to duplicate this setup. Could you please tell me how high(low?) you have the center of the propellor from the hull? Also, what diameter and pitch prop are you using. I am going to use a 2800 kv 4 pole inrunner(2850) and experiment with 2 and 3s batteries. Also, when you sanded the hull did you just try to make the bottom flat or was it a little nose high? I am newish to boats. I plan on using the blackjack 24 propshaft setup.

Thanks,

Jeff

[Davey80]

It's taken awhile...like a year but I finally got back to this and got it finished! Decided to scrap the trim tab plan and go for the flex shaft conversion. Many thanks to Dr. Jet, H&YRacing, and Trigger, for their input. All were beneficial in helping me decide how to move forward on this.

Enjoy the pics

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[Davey80]

Parts List:

1) DYNM3860 DYNAMITE 30A MARINE ESC
2) LEOPARD 2845 2550KV MOTOR & COOLING JACKET
3) ASSOCIATED XP120 TX/RX
4) OSE .098 FLEX SHAFT ASSEMBLY / COUPLER
5) K&S 3/16 BRASS STUFFING TUBE
6) POWERHOBBY 3S 1500 MAH BATTERIES
7) ZAP Z-POXY 5 MINUTE ADHESIVE
8) OSE CNC PROP 32mm - 1/8" BORE
9) AQUB8813 AQUACRAFT GP-1 STRUT ASSEMBLY
10) TAMIYA TS-92 METALLIC ORANGE
11) TAMIYA TS-79 SEMI GLOSS CLEAR
12) OSE 1345 4MM COUPLER

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