F1h2o

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F1h2o Italian jobYouCut_202_00_00_12_09-9-2023 13_16_23.jpg

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New record speed this morning. 37.7 mph. 60.67kph. I feel this could be the maximum, nice to break the 60kph mark.
The water was flat calm so great for record breaking. The trim was a degree down on last time which made the difference.
I had to get the rescue boat out at one point when the 200amp watt meter stopped working, another for the bin

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Thank you very kind....so I weighed it today. With 2 x 3s batteries it weighs 13lbs, or 5.9kg. I said it was heavy, but maybe that adds a realistic touch as to the way it runs, she can fair skip along. It's the fastest boat I have powered by my own design gear drive outboard . It's nice to know my outboards are so capable at reaching good speed. Without engine and batteries, bare boat weight, about 3.6kg. 8lbs

[srislash]

After today's meeting I have a long list of alterations to work on, but isn't that the way.
It was always intended to be scale with enough speed to make it realistic. With hindsight I should have saved weight wherever possible.
There is a new video to watch.

what kind of running weight are you at? I would think 6 to 7lbs would be a goal
But honestly I love the look and you’ve done stellar work on this.

Shawn

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After today's meeting I have a long list of alterations to work on, but isn't that the way.
It was always intended to be scale with enough speed to make it realistic. With hindsight I should have saved weight wherever possible.
There is a new video to watch.

[NativePaul]

Yeah consistent trim angles are critical, I had a boat that was handling all wonky and after some head scratching it turned out that the single m5 bolt on the strut wasn't up to the taks of keeping it in place and it would allow the trim to set itself; while I think that a bigger strut and bracket for 2 bolts is the answer for the next boat, as a quick and easy fix I glued 2 sandpaper "washers" back to back and put that between the bracket and strut which improved the friction between them and prevented further unwanted movement.

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F1h2o Italian job

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Thanks Paul. So I tried the 25mm up position, and managed to flip her over, now I know she floats upside-down. I think I will stick with the 20mm up position, which I changed back too at the lake. No water damage apparent except for the watt meter so good for another run without the watt meter in-line. Maybe that made a difference in current flow because a new record was achieved 36.3mph. (58.4kph)
I have ordered a 44mm 3blade ally tfl prop , thinking this might be my regular go to prop when not looking for breaking speed records.
I can alter the trim angle on the outboard, but the huge forces involved can easily alter my settings, maybe look at altering the design.

[NativePaul]

I'm glad to hear that it worked out for you.

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F1h2o Italian job

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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.

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F1h2o Italian job

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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.

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F1 h2o20230831_114107.jpg

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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.20230831_100715.jpg

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https://youtube.com/watch?v=5gcgP0QzrAA&si=9U0ItOM7A4u0zB7T

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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.20230830_161631.jpg20230830_165146.jpg

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20230829_163730.jpgF1h2o Italian job

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Thanks Paul you explained it well. 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.

[NativePaul]

I do have ways of raising the engine, but so far I've found my props suck air in and loose traction if too near the surface. Which is why I added the hydrofoil cum anti ventilation plate. However I could produce a special short shaft version of my outboard just for this model, the mid section being 20 to 25mm shorter. Instead of filling with oil I would pack it with high quality grease, sealed for life, this would help me make it shorter. I think testing on the water will show which is the best way. I might make a battery bay cover just for testing with a gps window and a watt meter.
What will be the effect of it being too low, is it just loss of speed, or will it try and take off, ie poor handling?

Both, the main benefit of surface drive is reducing drag by getting most of your leg and prop hub out of the water, but a surface piercing prop will also have prop lift (high and low lift props are available but even a low lift will be lifting the rear and thus pushing the nose down to some extent) so you will likely needless trim angle. Performance aside surface drive gives you a rooster tail like the full size ones have.
Cavitation is the downside to surface drive, there is really no way around it, they will do it and you lose low speed acceleation because of it in order to gain high end speed, but the props are designed for it with an ethos more along the lines of grabbing cups of water and throwing them backwards to provide thrust, than the traditional submerged prop screwing it's way through the water.
You have a surface drive prop running submerged but close to the surface which is not the optimal combo, if you decide not to lift the prop up switching to a prop designed to run submerged like an eco or fsrv prop would increase your performance and reduce your cavitation.

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20230827_083940.jpgOur club doesn't allow combustion engines due to pollution and noise. Also I can design and build my own electric outboards which to me is more satisfying than the actual running. If they did allow them I love those arrow shark 1/4 scale with actual petrol engines, they look and sound like the real thing