JAE Mini Sprint

[wparsons]

Still trying to figure out what motor to use for this when I build it anyone know of a 4s motor that would work or would the batteries be to big & not sure what prop to use??
Like this motor for instance with a 60amp esc??
http://www.hobbyking.com/hobbyking/s...dProduct=11179

Or would this hold up to 4s?
http://www.hobbypartz.com/96m05-car-2040-3600.html

3600kv on 4s is asking for trouble, that's A LOT of rpm (60k rpm unloaded) on that motor. Even the 2900kv motor is a lot for 4s, that's still almost 50k rpm unloaded.

[monojeff]

Yeah thats what I figured best stay with 3s.
What do you guys think about running a Traxxas 380 4000kv motor in it on 3s, I already have this motor and hydrojerry is running it in his mini geico on 3s.

[slowride]

YES, now I want one...

[monojeff]

YES, now I want one...

You saying you want a mini sprint or the motor I was talking about?

[martin]

Ive been out 3 times with my Mini Sprint & must say this is a fabulous little boat, It handles unbelievably well espacially in the turns where you can turn flat out & its on rails. But you must understand this boat was designed around 2s & the speeds & loads that you will get on this setup to which the boat will perform within its capabilitys. How ever if your going to run 3s & depending on the motor & set up your going to use will obviously depend on the speeds & loads that your going to put on the boat which are obviously going to be higher than stock 2 s set up.As i said i run 3s with 3800kv on 60c & started with everything turned down (esc settings & stock prop). I threw a blade within 4-5 laps (i normaly always use metal props).Continued.

[monojeff]

Thanks I realize this and plan to run it 2s but figured why not try it on 3s also for some all out speed runs!

[martin]

Second time out i tore the wooden rudder bracket off going into a turn flat out right in front of me,I believe it was purly the higher load put on the rudder in the turn that caused it to break, So my suggestion is fit a metal bracket & not the wooden one.Repared with metal bracket & went out again,Water had slight chop so not quite as fast but pulled rear self tapping screw out on the turn fin & twisted the fin slightly.I have now put tapped inserts with heads on right through sponson but you could just brill right through the dowl & use a bolt with a lock nut all the way through the sponson. I also had the rear boom tube slide accross 1/4" in the tub so will be using metal collars & not the zip ties in future.Once ironed out this is going to be a great boat. Martin.

[martin]

One thing im pleased with how its working is the wire drive shaft assembly that i made which i use 2 off 3mm id x7mm od ballbearings with a 3mm stub drilled to 30mm deep & Loctite 603 & a .048" wire shaft going into an Etti 1.2mm collet coupling. I also made positve fixings at the front & rear of hatch so i wasnt relying on just the tape holding the hatch on in the event of high speed crashes. Martin.

[teddyboy]

I got my JAE mini sprint out on the pond this weekend and it a hoot to drive. No bad habits and handles extremely well. It is also fast for the size with the 2200 mA lipos under the hood. Special thanks to Mike Walker for the first class build.

[Mike Walker]

Hey, glad your having fun with it
Thanks

[geraghty]

Martin,
When I designed the boat,I never intended it to be a structural test dummy for mini FE applications..
I have to admit however,I knew some RC boater would step up and try to find the boats structural design limits.....LOLOLOL
Of course you are going to have to beef the boat up structurally to withstand what you are putting it through....:-):-)......the videos are just great.....:-)
If anybody builds this boat per the instructions and uses the suggested equipment I used in the prototype ,the boat should last for 50 years.......
Your videos are a testimonial to just how good a kit the Zippkits Mini-Sprint is right from the factory.....
Enjoy the experience of a JAE......
Rod Geraghty

[martin]

Rod i agree 100% with the strength of the kit if you run within the bounds of the design, ( how many rc boaters stick to the script ). Joking aside the build & material designs are spot on if you keep within the bounds as with anything you will allways get those that have to push things like me. I now have to build a new boat as of last night, I was out testing looking for a bit more speed & had radio problem where i lost steering & went wot into concrete bank. These little rc hydros are addictive, Must be something to do with the 40years i run tethered ic hydros. Thanks again for a great design boat, Must go & start the new build now. Martin.

[NativePaul]

Oh poop, I missed that, sorry for your loss Martin, I guess that's what sparked off your questions about a new radio.

You should join the MPBA and come along to the records day at Burton-on-Trent at the end of the race season, I bet you'll kick all our butts and get your name in the books.

[martin]

Thanks Paul,Yes deff new radio.Boat was a mess.Id fitted 6mm solid carbon boom tubes along with 8mm od ally tubes through the tub to take the extra loads but a concrete bank wasnt in the plans.Where it hit head on the lipo which was a newish Overlander extreem pro 60c shot foward (it had a velcro strap right round it & sat on the rubber draw liner mat also to stop it sliding.The lipo hit the ally tube with such force it pushed the tube 1/2" foward where its glued into the side of the tub, Bent the ally tube & the lipo ended up with the impression of the tube in the end of the lipo.Unplugged everything & went straight home,Bearing in mind the boat sunk so lipo was cool.By the time i got home you could hardly hold the lipo,I assume it had shorted looking at the damage to the lipo. Martin

[martin]

I am a member of the MPBA (Model hydro club ) since around 1969. Martin.