Spirit of Texas Drag Hydro

[drwayne]

Ok Doc ... props are done!

[ATTACH=CONFIG]92720[/ATTACH]

marvelous.
now you'd best pm me the costly details !
Thx
W

[Xzessperated]

Ok Doc ... props are done!

Unlike · Comment · Share

Patrick Wellard likes this

[Richie the shipwright]

In relation with the corner..Which prop would be affected by disturbed waterflow...? inside or outside?? ive heard both arguments, both make sense... but which is really the lesser of two evils?

Drag and aerated water from propblast on rudder....
Or disturbed waterflow (from rudder) to prop???

If it's the inside prop thats affected, Wouldnt this disturbed waterflow cause the undistubed prop to have more thrust than the prop IN the disturbed water?? Causing the boat to turn better/faster???

Good job with the temp cowl doc. :-)

[Megabiker98]

In relation with the corner..Which prop would be affected by disturbed waterflow...? inside or outside?? ive heard both arguments, both make sense... but which is really the lesser of two evils?

Drag and aerated water from propblast on rudder....
Or disturbed waterflow (from rudder) to prop???

If it's the inside prop thats affected, Wouldnt this disturbed waterflow cause the undistubed prop to have more thrust than the prop IN the disturbed water?? Causing the boat to turn better/faster???

Good job with the temp cowl doc. :-)

my guess is that with the rudder in front of props when u turn one way it will force water to that side which will give more thrust due to more water hitting the full prop, therefor making one side push more! I could be completely wrong also! I think either side could be argued as only way to find out is to test it!

[egneg]

In oval racing you always turn in the same direction thus the one motor would have a greater load that may lead to overheating.

[drwayne]

Took the beasty out today for its' maiden, using the temp cowl.

Woohoo !
slight water ingress up the shaft outers , couple tablespoon's worth, absorbed by strategically placed paper towel.
It floats on a cushion of air at 65mph+, and has positive buoyancy !


hopefully Richie and/or Wade will post video soon

In oval racing you always turn in the same direction thus the one motor would have a greater load that may lead to overheating.

IME the inside of corner motor returns warmer/hotter

[Richie the shipwright]

Dont worry doc.. videos i took turned out great. I checked again........the first duck the boat "buzzed" definately crapped himself!! :-)

Think the fish got a bit of a fright too... He..he...he... bouyancy....CHECK!!!! HELL FUNNY MATE!!!!

[Megabiker98]

Hahaha sweet!!! About how fast would u day it went??

[drwayne]

Hahaha sweet!!! About how fast would u day it went??

65mph+

Became dangerous to drive much over half throttle.. reliant on prop thrust to keep direction .. ( my jaw dropped....)steering is woefully poor, do need to address that to circulate inside these concrete walled ponds !.......

videos look a blast !

tore a M3 bolt from servo mount ! .. damn there's some forces here.
Have higher torque servo.. is possible the used has insufficient to turn against the twin thrust cones .. ?

[Heaving Earth]

It's possible. Try it. Had you thought about putting a longer narrower rudder on? Maybe short and wide isn't the best option

[Megabiker98]

The not so great turning could just have todo with the hull, if u think about it, the full scale drag boats have bloody TERRIBLE turning radius's!!!!

[drwayne]

It's possible. Try it. Had you thought about putting a longer narrower rudder on? Maybe short and wide isn't the best option

5.5" x 1" now....extends 2.5 below prop centre.
here is the list of maybes
1. maybe rudder servo too weak ( 13Kg)
2. maybe thrust cones from both props, with rudder 1" behind, degrades steering due aeration/turbulation ?
2a. however the water pickups on rudder performed well, with outlets spraying2 foot to the side as it passed.
3. maybe needs a larger turn fin ( has 3x2" now )
4. maybe it's just overpowered ( eek, slap me quick ! )

[785boats]

Doc.
Have you thought of reversing the props (& shafts) & motor direction so that the props turn in at the top instead of out. I know that one way is better than the other but I can't remember which.
Also, I know that it is a different kettle of fish, but the big twin riggers have the props spinning the same way or they just won't turn. Could it be the same with a twin V with the drives close together?

[drwayne]

The not so great turning could just have todo with the hull, if u think about it, the full scale drag boats have bloody TERRIBLE turning radius's!!!!

Hydros pivot around the turnfin.
The rudder moveent induces yaw which turns the boat.
Rudder movement here did nothing.
Either the rudder did not move ( servo too weak ?) or the prop wash blew beyond that rudder movement.
I know the last 1.5" in is water, as the pickups work well, but above that.. perhaps those top 4" are all froth and bubbles ?

[Megabiker98]

Ya true!!! Ya do u have counter rotating props??? And if u have an extra servo laying around can't hurt to try that out!!!