J.A.E. mini sprint build ?

[Andris Golts]

Hi all just in the process of building a mini sprint ?# 1 . Is using the tygon hose and tie wraps strong enough for boom clamps as some of these set ups reach 50 mph + ? Is mounting the turn fin with sheet metal screws into wooden doweling strong enough for these speeds ? Regards Andris Golts.

[martin]

If you build the boat stock with the given motor etc it will do around 40 mph & things will be ok. If however you intend to run at 50+ mph you need to change a few things, running these higher speeds with sharpe turns simply ripped the self tapping screws out that hold the turn fin onto the sponson. I bolted right through the sponson which cured that problem, another area you must address is the wooden rudder bracket. This will brake off, strengthen the bracket with a metal bracket bolted through the hull.

[jim82]

I have not had a problem with turn fin. I use 2 zips per tubing for clamps and does fine.

[Andris Golts]

Thanks for the two great replies. Regards Andris Golts.

[martin]

It depends on what type of running you are doing, if you are doing ovals with a stock motor etc things are fine. I use uprated motors turning at 42000rpm unloaded with pretty sharp turning with the boat (smallish lake where sharp turns are needed). Probably running around 55mph which ripped the screws from the sponson & also snapped the wooden rudder bracket off whilst in a turn.

[jim82]

I'm running a leopard 4700kv on 3s and I have gps it at 57.2mph with a Garmin 201 taped to the top...lol

[bob horowitz]

I'm running a leopard 4700kv on 3s and I have gps it at 57.2mph with a Garmin 201 taped to the top...lol

Jim,
What ESC and prop are you running? Are you running any water cooling? The best I've gotten is about 52mph. I'm building up a new one, and I'm trying to figure out how to set it up. My old one has a water cooled Leopard 2845 with water cooling and a HK Blue 60 amp also with a cooling plate on it. I'm at work and I don't remember what KV. The new one is going to have a wire drive for sure, I have to decide what other equipment. Also running 3S, 2200 mah pack.
Regards,
Bob

[jim82]

I use tfl 432 on 3s short runs and Oct 632 detongue on 2s as for lipos turnigy 2200 heavy duty 3s and zippy compact 60c 2200 2s. ESC I use sk120 cooling plate removed.