Jae mini sprint carbon fiber wrap????

[crudeau]

So I ordered a mini sprint kit non prebuilt. I also have z poxy 30 and finish. I was thinking of wrapping the sponsons in lightweight carbon fiber and painting the hull. It would be my first build and first time with carbon fiber. Just wondering if you think it's too much weight and if tge finish epoxy would work with tge carbon fiber. I was thinking of getting the carbon fiber tape.

[crudeau]

I think I may just try to put the carbon fiber in the top or sides of the sponsons and paint tge rest. It's more just for tge look. Though I was thinking of using it on the rear to help stiffen up the transom inside. So more of my question is can I get carbon tape and stick it on the wood prior to the finishing epoxy. And use the finishing epoxy as the resin

[martin]

Yep you can use carbon tape on the rear of the tub to strengthen the wood where the rudder etc are bolted, this is what finishing resin is intended for as well as painting on the wood. You might want to put a couple of layers of carbon on to get a bit more thickness to it or you can stick a piece of carbon sheet on the rear. Go steady with how much carbon you use in other areas though as you are making the boat heavier which will affect performance if you go to heavy.

[crudeau]

I will have to evaluated ones its built. What's the recommended paint for hulls? Or does pretty much anything work. Since its epoxy my gut says to use enamel based like model paint

[siberianhusky]

If using spray cans I use the dupli color line, including primer. I use 2 part auto urethane for a clear coat, others use spray clear with no problems.
I've never used Krylon myself, buy my running buddy did on his SV and has issues with it crinkling, he followed the directions exactly.
Used plain old home depot white spray enamel on a hydro that has vinyl graphics, it went on very nice and has held up very well.
99% of the paint job is in the prep work though.
I've used model paint to do trim and windows etc, never tried painting an entire boat with it though.
Basically anything you're comfortable with will work, thought about some kind of stain and clear coat on my new Jae21.

[crudeau]

So I finally got my work bench built and am still waiting on some stuff before I start building. But I was wondering if maybe I should just not use the wood extension and use the aluminum mount that comes with the rudder. Seems easier to wrap tge inside and outside of the hull. Seems it would be stronger too. Any thoughts there? Or is it too much weight

[martin]

I dont use the wooden mount i use the alloy bracket bolted through the transome, from memory you have to shorten the angle bracket a bit so as to get the rudder in the same place as when using the wood bracket. I also add a flat alloy doubler bracket that bolts through the rudder bracket & runs along the side of the tub with 2 bolts going into the tub side.

[crudeau]

Sounds like exactly what I am looking to do. Is that a top secret mod or can pic or two be posted? Lol

[martin]

I will try & post a couple of pics tomorrow.

[martin]

8182281823Pics as promised.

[pyroM!KE]

8182281823Pics as promised.
Id like to see pics of your entire setup...Im currently building one with a 3500 on 3s....

[martin]

8188481885
81886

[pyroM!KE]

Nice!Thanks for the pis man! What is your motor esc setup..Also I see you didnt bolt the sponsons the the CF tubes..What prop are you running?

[martin]

Ive got 3 Leopard motors to try, 2845-4430kv on 3s, 2850-4400kv on 3s & 2860-3400kv. Prop on their is an Octura 1630 back cut but have run x435 detonqued & back cut when i had the outrunner motor fitted. Ill probably also try 1732 prop, esc is a T120a.

[eric_laermans]

@martin: it seems your JAE is a 21FE, not the Mini-Sprint(?). In that case the 2860 is certainly not too big/ heavy. In a rigger of the same size I used the 1535Lehner (2855) keeping the LiPo weight under 280gr, removing everything redundant to keep the weight low. Nice built though... like the hatch :-).

[martin]

Hi Eric its def a Mini Sprint 17" long, ive modded the top 2 times so as to get more room inside for various set ups. Yes i prefer the flat tops rather than the cowl tops. Their easier & more secure to tape down + i prefer see through tops so as to see whats happening inside ecspecialy to see if any water has got in.

[eric_laermans]

Okay, on photo it looked larger to me. My 17'' mini-rigger has a 2221-8 Hyperion weighing less than 80gr combined with an ETTI 45A ESC and 2600mAh 2s LiPo and 36mm steelprop. I would pick the Leopard 2845-4420kV (125gr) from your list on 3s with 32mm (1.4 pitch) prop. That should give her a topspeed of approx 60MPH. Using the 1732 prop might work/ might not work and propel her to 75MPH which is probably too much... :smile:

[martin]

http://www.youtube.com/watch?v=nOUlQEGC8lg
Eric this is my Mini Sprint before i modded the top & also added 6mm boom tubes as the 3/16" tubes were not strong enough. Motor was a cheapo $12 Mystery 2636-3800kv outrunner on 3s 60c 2200mah with 60amp esc & Octura x435 detongued & back cut. Should be much faster now with the Leopard inrunners though.

[eric_laermans]

That's ballistic! :beerchug: Almost SAW speed with oval-handling. I never tried these kind of setups as I also run competitions in which during 5 minutes we need to do ovals. Do you consider the ridepad valuable in gaining speed? Rgrdz Eric

[martin]

Bearing in mind this has a cheapo motor, if the turn fin was either removed or a much smaller one was fitted for SAW runs only i think the straight line speed would increase a fair bit faster but with no turns only low speed turns at best. Re the rear ride pad im not sure whether that creates drag as you seem to get a fair bit of spray coming off of it but it does have other benifits that probably out weigh a slight drag effect though. Cant wait to run it with a 800w & 1000w motor though.

[brett657]

Yes... you can use carbon tape on the rear of the tub to strengthen the wood You might want to put a couple of layers of carbon on to get a bit more thickness to it or you can stick a piece of carbon sheet on the rear.where this is intended as painting on the wood. Go steady with how much carbon you use in other areas though as you are making the boat heavier which will affect performance if you go to heavy and very Nice pics Thanks martin...

Regards
brett
Nitrotek (http://www.nitrotek.nl/rc-boten.html)

[Meniscus]

Maybe not for this build, but you guys may be interested in this article for the future: http://www.modelgasboats.com/Composites_in_model_boat_construction/

[Gary Mullens]

http://www.youtube.com/watch?v=nOUlQEGC8lg
Eric this is my Mini Sprint before i modded the top & also added 6mm boom tubes as the 3/16" tubes were not strong enough. Motor was a cheapo $12 Mystery 2636-3800kv outrunner on 3s 60c 2200mah with 60amp esc & Octura x435 detongued & back cut. Should be much faster now with the Leopard inrunners though.

Martin, Care to share how much more in height you added to the build? Also, what is the brass mod you did on the 6mm tubes?

Thanks,
-Gary

[martin]

Hi Gary i added 5/8" in height but slightly less at the front & rear as i wanted a curved top to give a bit of shape rather than a flat top. Martin.

[martin]

I also upgraded the carbon boom tubes as the stock 3/16" were not strong enough for what i wanted, here in the UK we cant get imperial diameter carbon only metric. So went with 6mm diam carbon, obviously had to change the brass tube in the sponsons & in the tub to larger brass to take the 6mm carbon boom tubes. I also had to make new sponsons due to destroying them in a crash so made the sponsons a tad higher on the top so as to get more material above where the tubes go into the sponson as i also add hard wood blocks inside the sponson to strengthen where the tubes are bonded in. Martin.

[Gary Mullens]

Martin, What are the little clamps that hold the boom to the tube and where can I get some?
Thanks,
-Gary

[martin]

I made the collars, their are various collars around for doing this same job on riggers. Dont know of their sizing though as ive never had to buy any.

[Gary Mullens]

Martin, What is the length from the transom to the back side of the rudder? Also, Are you using the right angle piece and the aluminum that is mounted on the side for a rudder mount? How thick and what is the length of the aluminum piece that is mounted on the side?

Thanks,
-Gary

[martin]

From the transome to the rear of the rudder is 2.75", i also dont use the stock wooden bracket as on the kit i use the full aluminium bracket that the rudder comes with. You do need to cut the piece of angle on the rudder a bit shorter otherwise the rudder is to far off the transome. The flat plate i use is 1/16" thick x 7/8" wide & 2.75" long with the front of the plate bevelled 45 degrees. To sum up the rudder is bolted through the rear of the transome with the mounting angle & also through the side with the flat plate.

[Gary Mullens]

From the transome to the rear of the rudder is 2.75", i also dont use the stock wooden bracket as on the kit i use the full aluminium bracket that the rudder comes with. You do need to cut the piece of angle on the rudder a bit shorter otherwise the rudder is to far off the transome. The flat plate i use is 1/16" thick x 7/8" wide & 2.75" long with the front of the plate bevelled 45 degrees. To sum up the rudder is bolted through the rear of the transome with the mounting angle & also through the side with the flat plate.

Thanks Martin. Looks like in the pic's you posted that their may be a piece of ply added on the outside of the tum where the 1/16 aluminum piece is mounted. Is this the the standard with the kit or something you added as well?

[martin]

I added the thin ply doubler that you can see, theirs also a shorter one inside the tub so the aluminium flat plate bolt through all of this. The main reason for this mod was i originally use the stock wooden rudder bracket but due to the high speed sharpe turns tore the rudder of first time out which left a hole & splits in the ply side.

[Gary Mullens]

I added the thin ply doubler that you can see, theirs also a shorter one inside the tub so the aluminium flat plate bolt through all of this. The main reason for this mod was i originally use the stock wooden rudder bracket but due to the high speed sharpe turns tore the rudder of first time out which left a hole & splits in the ply side.

What thickness did you use for the ply doubler on the outside and inside? Did you use wood type screws or machine screws with nuts?

[martin]

You wont need to add doublers as i did, this was only done to repair the damage hole & splits in the side where the rudder was torn off. The doublers were only 1/32" ply by the way, if your bolting the rudder to the transome & the flat plate to the side you wont need doublers. The screws through the side plate are machine screws with nuts, the bolts through the transome rudder bracket are 3mm allen bolts.

[Gary Mullens]

I also upgraded the carbon boom tubes as the stock 3/16" were not strong enough for what i wanted, here in the UK we cant get imperial diameter carbon only metric. So went with 6mm diam carbon, obviously had to change the brass tube in the sponsons & in the tub to larger brass to take the 6mm carbon boom tubes. I also had to make new sponsons due to destroying them in a crash so made the sponsons a tad higher on the top so as to get more material above where the tubes go into the sponson as i also add hard wood blocks inside the sponson to strengthen where the tubes are bonded in. Martin.

Martin, When you added the 5/8" in height to the tub, how much height did you add to the sponsons with the 6mm tubes?
-Gary

[martin]

+ 3/16".

[Gary Mullens]

Thanks Martin. What kind of run times are you getting?
-Gary

[martin]

At around 42000rpm unloaded i limit run times to about 1 min then cool down, out of a 2200mah battery i get around 3.5 min total run time whilst still leaving 20% in the battery. So puting around 1760mah back in on recharge.