Dragon SAW Record boat details

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Kris Flynn

Well-Known Member
Joined
Mar 11, 2002
Messages
4,335
When I was younger, I spent ALOT of time trawling the internet for photos of what the fast guys were doing. I designed a few tunnels which seemed to work well for their purpose back then. I always told myself that once I got to my goal of breaking 80mph I would share everything about the design to try and help someone else go even faster...we all need something to chase
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So here are the photos of my 4S SAW tunnel. Nothing too special IMHO
THE BEST ADVISE I can give for what I have seen is what is on the bottom counts for 80% and the top 20% (best guess numbers, but give you an idea of where to look for more).

If you want an more information about something, please ask below.

Hull: Dragon M11 Center section and 30" SAW sponsons. The same hull i nearly destroyed a few months ago as seen this link https://www.intlwaters.com/threads/dragon-repairs-rebuild.76274/.
Outboard: heavily modified lawless 3.5 with OS hinge plate and prop shaft.
Radio: Futaba 4PX + 614FS Receiver
Motor: TP 3640 4D home made cooling can
ESC: Castle 200 ICE cooling added by Darin Jordan
Batteries: Roaring Top 4S1P 5100mah 80c
(I cannot stress how important it is to pre warm your packs to 25-30degC when doing hard runs or even just mucking around...much nicer on all the equipment)
Plugs: OSE 5.5mm all round
Steering Servo: Hitec 7954SH (hiding under ESC)

Setup has more in it as it was only pulling around 250amps during the passes

Eagletree GPS for what had been very accurate speed readings. It logged over 140kph (88mph) on the pass I averaged 137kph through the traps.

Funny thing is that I know it wasn't really running perfect...so something to work on!

Photos can be found here: https://www.intlwaters.com/media/albums/dragons.2677/
 
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Kris,

First off, CONGRATS on the speed. I'm jealous!!!! Going to try and see what I can do for 1/4 and 1/3 mile TT next year. Have to build a boat just for those attempts.

Can ya share what prop you were running? Any better pics of the motor/lower unit? Still using the square end on top?
 
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Hey Mark,

Great to hear you will be having a crack next year! Time Trials can make or break people haha

Hopefully this photo helps.

Yep, square drive both ends
 

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Thanks mate! It's giving me ideas on what to do with my 3.5 Lawless lower... Might have to hit you up for those cables. Figure they are shorter than normal K&B or OS shafts.

The club is now running, basicly, only TT events with a few club fun runs here and there. Our pond is truely a tunnel paradise. Most of times it smooth as glass.
 
Should have asked before. But why the Lawless over the O.S. lower?? Both are outstanding units. Is it possible that the Lawless would take to mounting the motor lower better than O.S...
 
What does the boat weigh sitting in the water waiting for the trigger to be pulled...?
 
Congratulations Kris, curious why you went with a 3640 motor instead of a 4040 motor? I believe we met at one of my electric only Saw events in Las Angeles several years ago. I remember your tunnels you brought.


Mark
 
Hey Mark,

Thanks a lot! Yes we did meet and have a chat in Nov 2014 when the Germans were there :)

I chose the 3640 as it was ALOT lighter that the 4040 I also have in a similar KV. I needed/wanted the CoG further forward and this was a good way to reduce weight hanging off the back and move it forward :)
Both motors appeared to pull similar amps and RPM with similar props.

This current boat is a lot nicer to drive and get up to speed than the one i had in the USA. Interesting also to note that I had my standard M11 4S boat up to 120kph (75mph) with a Neu 1515 1y and a Buass prepped 1715...So I will be doing more testing on that setup after we do our 2lap event in 2 weeks :)
 
Kris,
I agree that 36mm motors are often overlooked. Smaller diameter rotors seem to spool up RPM's better. Are you sure you need a cooling can on an outboard? Saves quite a few grams especially full of water. The motor is in a better free air position than a car that has no water cooling. That and more cooling water available for the ESC.
Mic
 
Great work Kris and for sharing your info..

If only more people did the same :D

Kris,
I agree that 36mm motors are often overlooked. Smaller diameter rotors seem to spool up RPM's better. Are you sure you need a cooling can on an outboard? Saves quite a few grams especially full of water. The motor is in a better free air position than a car that has no water cooling. That and more cooling water available for the ESC.
Mic

My home made cooling can does not weigh much at all, especially to the ones 'off the shelf' sold be OSE and others. Would be around the same as a standard TP cooling can I think. Weight is also not the enemy always!
The ESC is getting the coolest water as it is, the motor gets the water after the ESC, so pretty sure we cannot get much better than that.
The motor also does get fairly warm after a few passes even with the cooling.
 
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