Scratch built ribs and outboards

What props do you use?

 

Tfl cnc 3 blade 46mm 1.4 p

 

Like this ,maybe try a 4519 two blade

 

F1h2o
Boat club yesterday morning, then try to sort printer it's thrown a massive wobbly. After much head scratching I think it was in need of a new nozzle, which seems to have done the trick. Then I finished the wrap, with teatime upon me I started masking off the windows. I had to be called down for dinner, whoops.
I didn't want to leave the tapes on overnight so went back to finish it, only a short drying time and peeled off the tapes, wow it brought it to life, pleased that went well.

 

Pleased that went well, getting all these on without messing any up is quite a challenge. Wing mirrors next.

 

F1h2o Italian job
It's been a difficult day, notice the red wing mirror is now white. The red didn't dry, so spent an hour rubbing them down , repainting, white probably looks better anyway. In between that I have been trying to fix the printer, at one time it just kept switching off . Anyway I've ordered a new hot end from aliexpress so will have to do without for a while, hope that sorts it.

 

F1h2o Italian job!
Photo 1, a short length of 1.6mm wire, no bends needed, gives steering servo an easy job.
Photo 2, Seems very close without a wire extension, maybe I could make those brass tube adapters in the photo an inch longer and solder the esc wires directly to them. Covered in heatshrink of course.
Printer....I watched a utube video of how to clean out the hot end on my anycubic vyper, excellent, so will try it, it's been used for over a year so guess it's overdue for a service. I can recommend this printer, which I did to club mate Philip, he loves it too.

 

F1h2o Italian job
Maiden on Wednesday if all goes well
One meter from nose to rear of outboard

 

F1h2o Italian job

Made a carrier cum work station for the f1 all ready now for tomorrow's meeting. She is heavy and will sit low in the water, but should rise up when moving.
The rear battery has leap froged the front battery into a forward position, this brings the cg somewhere near. I could try the jet outboard on this boat to reduce weight at the back, and there is always the option to build a shorter/lighter prop outboard.
Getting all the wires and cowl in place is tricky , done by having the rear end loose at the same time.

 

Keep it as to scale as possible, no jet-outboard!

 

It went well, she is easy to stear good turning circle and runs in straight line. Too much spray caused by engine too low down, so when parts for the printer come from China that will be the first job. Best speed of the day was 24mph. She is capable of more by bringing the prop higher I'm sure.
I slipped up by cutting slots to allow the rear end to fit, it let's water in. So I have reinstated the wood and cut the slots in the plastic rear end instead, see photos.

 

That prop must be way higher .
Like the picture I shared.
Then it must be way better.

 

Nice maiden!
Indeed such a propeller needs to run halve above water in order to reach insane speeds like the boats of Tamiya1970!
As with jet-boats trimming is vital to get a good running model.
Your halve way already, well done!

I am confident the next run will be a lot faster!
Hope you will get your 3D printer parts soon.

 

F1 h2o
I found the blue mount in my bits, it's 21mm higher than the white one. Then by pure luck putting the steering arm under its mount and the coupling below, it ended up perfectly inline. So good to go again, leak sorted and engine raised.

 

Hard to tell from the pictures, but it looks still a few millimeters too deep!
Again, run it, test it and you will know.
Do not forget your speed-o-meter

And the ventilation plate has no use on this one!

 

Indeed still to deep .

 

F1h2o Italian job
The photo shows the engine 20mm higher, I don't think it looks too bad. I have made some parts ready to lift it another 10mm , but first it has to pass test number 1, ie. 20mm, got a feeling I might be disappointed with the result, maybe my engine isn't designed to work this high up. Thinking back to its development it was all about removing ventilation, so this is going against the grain. We shall see this morning.
My printer seems to be fixed, got the new parts yesterday.

 

In reality an outboard for these tunnelhulls has a much shorter tail than the outboard it is derived from (due to the supercavitating propellers. Yes, cavitation ).
Although you need to alter your design and reprint some parts, and shorten possibly your vertical axis...if scale is where you are aiming for, make it shorter!

But first test this set-up!

 

F1h2o Italian job
Wow it worked, 20mm higher made a huge difference, so as predicted a few seconds needed to get going, but then it flies off the mark , skimming across the surface. 32mph then 33.3 mph. But the peak amps were 222A and 230A respectively.....not sure how I got away with that. My esc is rated 150A but burst amps is 900A. I am guessing she only peaks in the few seconds needed to plane.
Dropping down prop diameter from 46mm to 42mm still produced 30mph with a peak of 168 amps.
Just to try I raised the engine up a further 10mm, too much, now she struggled to plane and the handling was spoilt, it did manage 29mph on 46mm prop at 132 amps.
So now I have lowered it 5mm , bringing it to 25mm up from the original position, in the hope of good speed and handling at lower amps.
I kept checking temperatures throughout and nothing got much over 30 degrees except the oil in the gearbox which hit 36 degrees. So the new cooling method of taking it from the outboard into the esc then out the back of the boat works really well.