1/10 Crackerbox brushless build

[befu]

Rudder mounted

Rudder is on the back of the boat now. Fits well, kicks up and looks like it will work. Not sure on the urethane casting resin, seems a bit brittle. I think the stuff I am using is only 3000 psi. You can get better resins, or I could just use epoxy. Harder to do, takes longer but for the few I need to make, it would work.

Getting close to running. With a 3s-1800 battery, I am looking at a running weight of 1 lb, 13 oz and it is one solid boat with the urethane foam and kevlar reinforcement.

Brian

[befu]

haven't forgotten

That looks great Brian!

I was looking at the hatch on my 18" mystic and it almost fits the 24" mono. I am going to do a cast of it and vacuum form some. I need one for mine as well as one to send with yours. The hull is ready to ship, but I want to send the hatch with it.

Trying to get some projects done and off the work bench!

Brian

[tiqueman]

I was looking at the hatch on my 18" mystic and it almost fits the 24" mono. I am going to do a cast of it and vacuum form some. I need one for mine as well as one to send with yours. The hull is ready to ship, but I want to send the hatch with it.

Trying to get some projects done and off the work bench!

Brian

That sounds great. No rush.

Someday I want to learn how vaccum form. Actually vacuum bagging is what Id like to give a whirl. Ive got a friend trying to get me to start tryin, I just dont know where to begin. I soon hope to build a single canopy hatch for my BJ26. Theres one out that Kintec offers, but I dont really like it. Looks too "toyish". That will be my first project Ive ever built a mold, made a plug and established a part. At least, I hope all 3 steps go that well.

[befu]

vacuum bagging

That sounds great. No rush.

Someday I want to learn how vaccum form. Actually vacuum bagging is what Id like to give a whirl. Ive got a friend trying to get me to start tryin, I just dont know where to begin. I soon hope to build a single canopy hatch for my BJ26. Theres one out that Kintec offers, but I dont really like it. Looks too "toyish". That will be my first project Ive ever built a mold, made a plug and established a part. At least, I hope all 3 steps go that well.

You can do some pretty incredible things with vacuum bagging. Keep in mind, you can get a very good layup just by hand if you take your time. I learned vacuum bagging back in 1990 working as grunt labor with the pattern model makers. Did some neat stuff for aerospace industry, LARGE molds. It is not that hard to do especially now with all the online videos available. I have made some very light boats in the past when fast electric was like our sport boats now due to battery weight and limitations.

I would like to build a larger vacuum former. Right now I am limited to 23" x 16" and that uses a 1/2" frame, so plastic is 22" x 15". Allow for a gap all the way around and 21" long is the max I can do. Just short of a 1/16 hydro

Lots of cool stuff out there to play with, just not enough time.

Brian

[tiqueman]

Lots of cool stuff out there to play with, just not enough time.

Or in most cases.. Money

[befu]

Its works!

tiqueman, need to fire up the vacuum former still.

Big news, ran a cracker box tonight to test it out and it works! This is the most scratch built I have ever done. make a vacuum former, make the plugs, make the hull, make the break away rudder using a plug, RTV mold and urethane, servo mount, water proof and cool the ESC, make the drive shaft and couplers.... Wow!

Well, ran it with a 2s-2200 battery, X431 octura red prop. Ran fine, definately slower than a race set up but good for the kids. Might try a 3s-1800 tomorrow.

It ran well enough and was pulling 13 amps +/- 1 amp at full throttle, dropping off to about 5 amps as I slowed it to turn. It was running wet also, tabs were too low. Might go up to a 35mm prop also, but have to get the kids racing first!

Not bad for a $21 delivered motor and ESC! Total cost with a couple lipo's and charger, RTR with AM radio will be under $80. And about $1500 in labor!

Brian

[tiqueman]

tiqueman, need to fire up the vacuum former still.

Big news, ran a cracker box tonight to test it out and it works! This is the most scratch built I have ever done. make a vacuum former, make the plugs, make the hull, make the break away rudder using a plug, RTV mold and urethane, servo mount, water proof and cool the ESC, make the drive shaft and couplers.... Wow!

Well, ran it with a 2s-2200 battery, X431 octura red prop. Ran fine, definately slower than a race set up but good for the kids. Might try a 3s-1800 tomorrow.

It ran well enough and was pulling 13 amps +/- 1 amp at full throttle, dropping off to about 5 amps as I slowed it to turn. It was running wet also, tabs were too low. Might go up to a 35mm prop also, but have to get the kids racing first!

Not bad for a $21 delivered motor and ESC! Total cost with a couple lipo's and charger, RTR with AM radio will be under $80. And about $1500 in labor!

Brian

Sounds good Brian. Thanks. I know youve been busy. No worries. Actually, Im gunna hit you up w/ a PM.. Ive got some ?s on something Im brain storming.... I think your the guy to talk to about it.


Get some vid up if you can. Id love to see one of these run!

[befu]

video

OK, so it is a bit rough. 10 year old running the camera. At one point, he starts calling in artillery strikes.....



Attached is a screen shot of the eagle tree data. This is the 1700kv outrunner, 2s-2200 20c turnigy lipo and a red x431 plastic prop.

Top speed is in the 16.5 to 17.5mph range, perfect for kids learning.

amperage is spiking to 15 amps on acceleration, but bounces around an average of 11 amps it looks like. Considering the motor is rated for 28 and the esc is 3s-30, it should be a nice running boat with 3s and up to a 35mm prop. I do not know what the top speed of the roar powered boats are, but should be a good class boat.

[tiqueman]

Brian, thats Tx looks nice! Hope everything went ok in Sector 6.

[forescott]

Still need more radios? I have a brand new am radio+receiver from an hpi savage flux I can donate.

[befu]

Still need more radios? I have a brand new am radio+receiver from an hpi savage flux I can donate.

Well, epoxying the receivers I think I ruined one, doesn't power up anymore. so I could still use another radio.

what do you have and let me know how much please.

Thank you,

Brian

[forescott]

Well, epoxying the receivers I think I ruined one, doesn't power up anymore. so I could still use another radio.

what do you have and let me know how much please.

Thank you,

Brian

PM sent

[forescott]

Got shipping $$$ I'll send the radio tues. morning! Here is a pic.... on the waay left.

[befu]

Running

Well, we ran two of the boats tonight. I think the 7.2v nicads bit the dust, they had no power as in idle out, turn around and limp back to shore.

Went to the 2s-2200 lipo and 27mm plastic prop. Fun running, kids did fine running in the local pond at the park. Second set of batteries my oldest hit the fountain in the middle of the pond and flipped. Knocked the driveshaft loose, so his fun was done for the day as I did not bring allen wrenches.

The boats ran well, but they tend to dig the nose in some. I bent the tabs up on one boat and then it started hopping. Bent them back down and it went well. We had a ton of rain so it was a bit flooded and water was dirty. You could tell when you hit some weeds as the nose of the boat would dip and you would plow water until you stopped.

After that, I decided to try a 3s-2200 battery. CG is definately to far forward, the lipos are too light! I got it up on plane and going and then nailed it. It lept up, then the transom lifted from the prop thrust and the nose went under. In the blink of an eye it turned into a submarine!

these are great and the boys are learning. I need to teach them how to "bring it in". They would just hit the beach at full speed and it would slide 3' up onto the grass. Rudder kicks up and the skeg protects the prop. We had a chat about that!

Next time I will have to get a video. Also might try running 2p on the lipos to get more weight in the boat and cg back. Run time on one pack was about 18 minutes. Speed was about 80 to 90 mph.

OK, maybe mid to upper teens! It is only a 1700kv motor on 2s with a 27mm prop. It will fit a 35mm prop, so plenty more testing to do.

Brian

[forescott]

Sounds cool! Did you get that radio I sent you Brian?