C1 Flowmaster 920EP

[TheShaddix]

Building another flowmaster. This one came as a twin already, but I took everything out to do it my own way.

The quality of the boat out of the box is pretty bad to say the least. There are visible seam lines under the paint, the fiberglass layup is mediocre, and just the weakness of this thing makes me regret this purchase, but it's too late to turn back. The paint colors are great. The paint quality, however, is not. But from afar it's definitely awesome looking. Definitely the last hull of this kind that I will ever build, especially for myself. I'm working on a c5009 in the meantime as well as some other projects.

The power setup will be:

2x leopard 3674 3270kv
2x swordfish 220A esc
4S lipos


http://imageshack.com/a/img673/2775/IyMsxx.jpg


http://imageshack.com/a/img538/5402/WBpf36.jpg

[lt130th]

I have one of these that I'm leaving in stock trim, except for upgrading the ESC's ad props, for my niece to run at the lake. What do make of that raised cavity blocking off the transom?? I can see what look like holes for mounting a rudder...like that used to be a transom. It's as if this hull was modified/lengthened from some existing design, and they just made some sloppy fix. It doesn't really make sense, otherwise. I thought about cutting it out, and throwing a layer of carbon fiber over the square hole on the inside, and gel-coating the outer side, flush...

[lt130th]

Are you ditching the magnets in the canopy? I notice you removed two from the hull already. One of the magnets in my canopy already came out. Found it stuck to the hull magnet, so they'll need some better epoxy if you're keeping the other four.

[lt130th]

One more thing, haha...your builds are typically thorough, but if it's not already in your plans, the stingers need more support where they mount. My starboard stinger shakes when I blip the throttle, and that's with carbon prop's. The other stinger remains rigid under throttle, so I think the fiberglass wall is too weak there. I've got to pull mine off and bond a carbon fiber plate to the inside, then drill out the screw holes and put the stingers back in with longer screws. Are you into wire drives? I ran a Jeff H. .078" wire with 4mm, stepped up to 3/16" stub shaft in a King of Shaves P1 which uses this same stinger. Would probably work out pretty nicely with all the extra Teflon liner they put in those stuffing tubes. Good Luck!

[Tamelesstgr]

Subscribing to this one

[TheShaddix]

My plan is to reinforce everything in this boat - all the mounting areas and such. i don't like that box piece that sticks inwards, no idea what it's for, but now that you said it could've started out as another hull style, it makes sense. I noticed after I tore everything out that the hull was originally meant to be a single drive as they actually filled the stuffing tube hole in the center with epoxy and painted it over on the outside, then covered up by wooden plates so no one would ever know. I am very disappointed in this hull overall, as I said. I was told about it by a friend who was super excited about its release. I hated to tell him that it was junk. I really feel bad for those people who will buy this boat and run it as is. It's so fragile I could barely keep the hatch from cracking when I was pulling the wood off of it, it's pathetically weak. When I did the usual in-tip epoxy pour I stuck the hull vertically into a bucket of water to cool it, then I noticed the epoxy was a bit too liquid... Turns out the hull had tiny holes in the front section and got flooded with water. Luckily the epoxy had cured regardless, so then I just poured in some more after getting the water out and drying it. But that is really crappy work by any standard because the ordinary buyer would get leaks and not even know the source.

Well, I have finally finished tearing out all the original epoxy and will begin sanding and do an inlay and reinforce the stinger mounting areas and the transom. I also want to do my own steering system with pull cables instead of a push rod as I find that much more precise and reliable.

Not into wire drives, had them on my hpr when I bought it, I don't think they are good as you're bending the wire constantly and it will eventually become weaker due to fatigue. It also puts more pressure on the motor bearings since the wire pushes it downwards. And another main reason is wires have no give in them, so you get full torque from motor to prop. A flex cable does not have any of those issues as it's designed to flex, absorbs that initial jerk, and bends and spins freely, and also has the screw effect which pushes water out from the stuffing tube. With a piano wire all you get to grease is the stinger, so it's much more prone to water leaks.

For the hatch I'll use slide-in bolts/bullets on one side and hatch bolts on the other. The magnets were a joke, not sure what they were thinking. I've had hatches fly off in mild crashes that had bolts holding them down. But it's just not worth all that work that I'm doing to it as the quality is poor and I wish I knew that before. Although it's not totally wasted. Should be decent once I'm done with it.

[boilo56]

What do make of that raised cavity blocking off the transom?? I can see what look like holes for mounting a rudder...like that used to be a transom. It's as if this hull was modified/lengthened from some existing design, and they just made some sloppy fix. It doesn't really make sense, otherwise. I thought about cutting it out, and throwing a layer of carbon fiber over the square hole on the inside, and gel-coating the outer side, flush...

Have you done something about it? I think it may cause a lot of drag when water hit the back part of that square cavity. I'm going to put a piece of clear tape over it and get some gps runs to compare speeds.

[lt130th]

Have you done something about it?

Not yet. That area should be out of the water once the boat gets on plane, but it still kind of irks me being there. It would be easy to cut it out, cover the hole and sand & polish some white gelcoat, flush. I have a handful of other boats I'm trying to make progress on right now.

[boilo56]

Ok, thanks! I'm working on mine at the moment. I've put some FG layers on the sides and bottom of the sponsons, I'm making a support for the back of the motors, because the aluminium they used for the brackets of the mount is too weak, and bend easely. I also ordered new motors and .130 flex shaft to replace the stock ones. After all this, we'll see!

[boilo56]

Any updates about your build, TheShaddix?

[TheShaddix]

I've been working on other boats, but here is what I got so far on this flowmaster... The inlay is done. Also converted the drives to use 3/16 flex cables. And ran out of water outlets so I just modified some inlets that I had, came out better than the actual outlets I was using!

Next is the motor mounts and rudder which I still need to figure out due to the awful rear section design. I can't remove the original rudder and install the one I want, so I'm forced to use what's there.


Note: I ended up using some floating bushings instead of the smaller ones pictured. Figured it would hold the cables better since they are longer. Also nevermind the crappy hatch cutout work, I'm still working on that to open up more hatch space.



http://imageshack.com/a/img540/937/NteOc7.jpg

[TheShaddix]

Some more progress...

http://imageshack.com/a/img540/7500/E7SCs4.jpg

http://imageshack.com/a/img661/9207/6RxlC8.jpg

[boilo56]

Looking good! Only a suggestion, i would double the thickness of the motor mounts. Great job on the boat!

[TheShaddix]

They are stronger than you'd think from their size. Plus it's too late now anyway.

[TheShaddix]

Finally finished the boat, did some water testing, will post some videos asap.


http://imageshack.com/a/img537/5906/5vZZ3b.jpg

http://imageshack.com/a/img537/1045/O6dIPV.jpg

http://imageshack.com/a/img537/8895/hEwoPL.jpg

http://imageshack.com/a/img537/2783/Nz8PnA.jpg

[Tamelesstgr]

That's an interesting stand, is that for space saving during storage? Also, can you tell me more about your servo wires connecting to the rudder? Is that straight wire you bent?

[TheShaddix]

That's a stand so I can place the boat vertically to work on the hardware, etc. Also for pouring epoxy into front/back. Just got tired of taping up hulls to table.

The servo is a pull-pull system, the arm is connected to the rudder by 2 wires.


http://imageshack.com/a/img537/93/ps2Vnq.jpg

[Tamelesstgr]

I like that idea for working on the hardware, boats that long take up a lot of bench space.

Excuse my ignorance, but is the cable flexible or is it like a stiff piece of wire? Reason I ask is because on my mono build I may need to move my servo location and it's not a straight shot to my rudder connection point.

[TheShaddix]

The cables are flexible, but they both are under tension so there is 0 flex. They pull on the rudder arm, there is no slack or delay in response. Every hpr/mhz boat has this system.

[lt130th]

https://www.youtube.com/watch?v=FR82ShhDpzA&feature=youtube_gdata_player

[Tamelesstgr]

Thanks for the video link, makes sense.

[Tamelesstgr]

Been really tempted to pick this hull up for sale locally. 100% stock with 2 batteries and a charger for $425

[TheShaddix]

Sounds like a great deal, but this hull, if not reinforced, is a piece of junk.

[Tamelesstgr]

I guess I was questioning if it was worthwhile without making the reinforcements to the hull (even though I neglected to type that)

[mabeldk4]

Any videos of this bad boy running?

[TheShaddix]

Actually, sold the boat to a friend, he set it up with 3674 2075 kv motors running on 6s. The boat is super stable and goes 90+ mph without breaking a sweat. I have a few videos i'll try to find. But this boat has definitely proven itself to be great, it just needs to be heavily reinforced for those speeds, especially the hatch.

[785boats]

Just to let you know also. A guy at our club had a bad flip. The side seams were reinforced but the leading edge of the tunnel, and the joins along the inside of the sponson tips, split wide open. Some extra strength in there is probably a good thing to do.

[mabeldk4]

Dang that is quite impressive actually, what props is he running? I just picked one of these up because they had them on sale, and I am going to reinforce it, just not sure how far to take it, only because I plan to turn my single motor setup in my Genesis into a dual. Might go all the way with the Genesis and make this one a good cruiser. Decisions decisions. Either way the boat looks cool just needs some tlc to make it rock!

[TheShaddix]

I reinforced all the inner seams too. He's had really nasty flips at 90 mph where he actually had to go for a swim a few times as the hatch flew off. Then I put in hatch bolts and now it's solid.

The props are 42mm octura, nothing special done to them other than your basic balance/sharpen. This boat has definitely impressed everyone as no one was expecting it be be so stable at those speeds. I think a lot of it has to do with how heavy the boat has become, especially loaded up with the giant 5000 mah 6s batteries. It's actually even stable than a lot of the bigger 45" cats I've seen. I will post a video if I don't forget.

[mabeldk4]

So I'm assuming you reinforced all the way up the sponsons? How were you able to do that? I haven't found anyone who has explained it clearly.

Maybe I will have to go all out on the flowmaster as well!

[TheShaddix]

I did the usual heavy mix of epoxy/silica/fiberglass, poured it in, rolled it around, etc. So far after so many heavy crashes there are no cracks or any stress marks. I also did the expandable foam which glued the two parts together. And I did the nose tip epoxy flood which made the entire nose solid epoxy. I've never had a hull fail after this kind of stuff done to it.

[mabeldk4]

That's what I figured, thanks for the info, I'm getting a better idea of what I would like to do. Still unsure if I want to go with a bigger 36xx motor or stick with a smaller set up like the tp 29xx

[Alessandro Garabaghi]

I picked up the same hull cause i wanted a boat to run from my deck instead of taking the 1:1 out =)

So far i like it... reading this makes me wonder, but so far everything seems strong enough and no issues with a few crashes ive had.

Really look for some suggestions of mods (props first... then esc / motors?) I bought 4 3s batteries so im wondering if im stuck with 3s, i suppose i could possibly build a dual 6s setup? and run all 4 batteries at once lol ...?

[Prodrvr]

Here's that vid...screamer!!
https://youtu.be/qOniot2zv80

[Prodrvr]

I've been working on other boats, but here is what I got so far on this flowmaster... The inlay is done. Also converted the drives to use 3/16 flex cables. And ran out of water outlets so I just modified some inlets that I had, came out better than the actual outlets I was using!

Next is the motor mounts and rudder which I still need to figure out due to the awful rear section design. I can't remove the original rudder and install the one I want, so I'm forced to use what's there.


Note: I ended up using some floating bushings instead of the smaller ones pictured. Figured it would hold the cables better since they are longer. Also nevermind the crappy hatch cutout work, I'm still working on that to open up more hatch space.



http://imageshack.com/a/img540/937/NteOc7.jpg


Where did you get the shaft bushings? I was just going to get a pair of 4mm flexshafts because they would fit without mods, but I have a pair of 3/16" shafts sitting here, so it would be cheaper to just get those bushings that you have there. Thanks!

[TheShaddix]

Got them on kintec

[Prodrvr]

Got them on kintec

Cool thanks!