Crusader.

[Beaux]

looks like that ought to work. Good job.

[785boats]

Thanks golfito, Beaux.

I just dug theses two pic out of my files.
The first one at rest, shows that the struts don't actually touch the water. Not even out where they attach to the sponsons. That's how my boat sat in the water.
The second pic shows the boat moving off at slow speed. See how the water is being pushed by the struts & how it flows over the struts & on the sponsons. That's exactly what happened with my model. The EDF just couldn't push the boat through it, & allow the front ski to lift up onto the plane with more speed.
Curious how both the full size boat & the model have that problem with the struts, when they aren't touching the water at rest. I can't understand it.

John-Cobb.jpg


crusader-jet-thrust-loch-ness-john-cobb-k6-wsr.JPG

How it should have been running.
04.jpg

[Jesse J]

I think there are two compounding effects.
The first is shared with the full scale: the bow wake lines up with the front strut and only hits it when underway at a specific early speed.
The second is that the edf doesn't have the thrust until it can have a sufficient amount of air moving through it.
The combination at that early speed is maximum drag and minimum thrust...
Solution, maybe a solid rocket booster?

[ray schrauwen]

I think there are two compounding effects.
The first is shared with the full scale: the bow wake lines up with the front strut and only hits it when underway at a specific early speed.
The second is that the edf doesn't have the thrust until it can have a sufficient amount of air moving through it.
The combination at that early speed is maximum drag and minimum thrust...
Solution, maybe a solid rocket booster?

Yeah BABY!!

[785boats]

Totally correct on both counts Jesse.
But another thing I have realised too, is that, at the slow speed the water also rides up the sides of the sponsons & over the top of them, completely burying them with a fair weight of water. This would also contribute to the hull not being able to lift up on to the plane.

[Jesse J]

Spray rails?

[785boats]

Yes. I thought of that as I typed the last post. Pity I didn't notice it in that photo before I took the fan out. I would have tried it. I didn't really recognise it on the model until I saw it in the photo & realised what it was doing. But the cog would still have been too far forward, I feel.
Should get a few test runs in tomorrow, I hope.
The spray rails might still be needed. We shall see.

[785boats]

I had a few successful runs with the Crusader today.
It was only at our smaller track at Boondal, not at our full race track, so I couldn't get it up to full speed. But it looks promising.
The first runs (not in either of the videos) were a bit bouncy when it was at high speed, so I added a tad of negative angle to the strut. Still couldn't use full throttle but it was much better at higher speed.
Prop was an x447/3 motor is an HET 4083 1080kv on 8s. I might drop it back to 6s, because I think it will be too far above scale speed when I open it right up.
Here's a couple of short videos posted on my channel. I'm happy with the way it performed. Even though it wasn't with an EDF.

https://www.youtube.com/channel/UCmc...Hpw83p9Hn-l1hg

[zooma]

Way better than the leaf blower power.

[785boats]

Unfortunately, yes.

[golfito]

I loved it. Beautiful model
I found a model recently that left me impressed:article-1341140-0C924F02000005DC-106_634x630.jpg

[785boats]

Thanks man.
Yes. I've really got to put some effort in, & finish mine off.

https://forums.offshoreelectrics.com...light=bluebird

[golfito]

Subscribed to the thread!

[Jesse J]

I had a few successful runs with the Crusader today.
It was only at our smaller track at Boondal, not at our full race track, so I couldn't get it up to full speed. But it looks promising.
The first runs (not in either of the videos) were a bit bouncy when it was at high speed, so I added a tad of negative angle to the strut. Still couldn't use full throttle but it was much better at higher speed.
Prop was an x447/3 motor is an HET 4083 1080kv on 8s. I might drop it back to 6s, because I think it will be too far above scale speed when I open it right up.
Here's a couple of short videos posted on my channel. I'm happy with the way it performed. Even though it wasn't with an EDF.

https://www.youtube.com/channel/UCmc...Hpw83p9Hn-l1hg

Looks real nice, even navigating the Lilly pads!

[785boats]

Thanks.
I got caught in the lilies a couple of times, & had to go out & get it.