Hospital Hop...how to stop it?

[InspGadgt]

#3 - You DO have a proper strut - Asking Horizon to put on a "proper strut" to a model being sold successfully "as is" for the last ten years or so (thousands sold) may not get you the response you're looking for.......

Mainly I'm just asking for the one that was supposed to be sold with the boat as I mistakenly thought I didn't already have it.

#5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but...

I'll definitely try the AoA and the air damn mod you have pictured. The aero mod I got from OSE is only a part of the testing to see what works. After more than 20 years of racing on-road RC I know not to do to many changes at once or you can't tell what is really working and what did not.

Lapping the brass bushing with a drill comes AFTER it's removed and can be inserted reasonably easy. To get yours out if it's that tight you might heat the stuffing tube (put a wet rag around the tube where it enters the hull to prevent heat transfer damage) and grab the end in vice grips. You might need to sacrifice the end but a replacement brass bushing doesn't cost much.

OR much easier and will allow less stressful strut angle adjustment :

Cut stuffing tube so that only 1/4" or so enters the strut and press in one at the rear and one right after where the stuffing tube ends.

https://www.offshoreelectrics.com/pr...od=oct-oc6ltsb

That looks like a much easier fix...is that a common mod done on this boat?

[InspGadgt]

Ok well heating didn't break the bushing free and I got a nice burn on my thumb while trying. So I ordered 2 replacement bushings and 2 of the bushings that was linked earlier. I'm going to have to crush the installed bushing to get it out...if it comes out after that I'll try the stock replacement bushings. If it damages the tube I'll cut it and use the other bushings. Thanks for all the help!

[InspGadgt]

I got the bushing out! I crushed the end with pliers so that it would start to pull away from the stuffing tube and it pulled right out. The end of the stuffing tube was pretty ratty so I figure that's what was locking the bushing in place. I sanded the stuffing tube end with an emory board then removed any flashing and restored the roundness with a body reamer tool. Now the new one just slides in easily except for where the flange meets the strut. The bushing is a really tight fit in the strut so I'm wondering how far it should go into the strut. I've pushed it in by hand as far as it will go but that is only like .5mm. I'm not sure if I should use a hammer and lightly tap it in deeper or sand the flange lightly so it fits more easily into the strut.

[InspGadgt]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

Attachment 160194

went to a squared-off turn fin : (picture prior to altering AoA)

Attachment 160195

https://www.youtube.com/watch?v=yicE1_TfDDY

So I'm getting closer to starting hull modifications and wanted to run something by you. In your air dam pic you cut a hole for the air to vent out of the side and it looks like it didn't compromise the integrity of the hull...I was thinking maybe it would be a good idea to remove the whole webbing piece...maybe an air dam might not be needed then as more air will be able to escape out the sides. If so do you think it will need some fiberglass reinforcement?

[InspGadgt]

So after trying a lot of different things like air dams and that lexan aero piece OSE sells and even sharpening and balancing the prop...none of them helped to stop the chine walk. It seems the consensus is this is a result of the boat trapping too much air under it so I finally committed to some hull modification to try and alleviate the issue. I cut off as much of the side webbing as I dared to allow the air to more easily escape out of the sides of the boat. I cut it down to where the side of the boat angles away. I have to wait for parts to arrive though before I can test it. My motor collet nut split yesterday and won't hold the shaft anymore.

Webbing removed.jpg

Webbing removed 2.jpg

[InspGadgt]

Didn't get a chance to test this past weekend due to a hurricane almost hitting us. Hopefully I will be able to this coming weekend.

[InspGadgt]

Well helping the air to escape did not solve the problem. I just can't seem to get this boat to perform

[properchopper]

Here's a thought ( you've read this from an earlier post in this thread) :

" #5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but....."

The rest is just Kabuki Theater..................

[CraigP]

ProperChopper is right in my opinion. The AoA is everything to getting a clean setup. But it’s a lot of work to change it... I’m not going to discuss specific angles, there’s more to it that that. But getting up to speed on what makes great hydro sponsons is worth looking into... I will say this, 3.85 degrees is TOO MUCH, lol!

[InspGadgt]

Here's a thought ( you've read this from an earlier post in this thread) :

" #5 - Regardless of how you adjust height/ angle (a tad too much height/angle and you'll have the rear hopping up and down - (I know this with knowingness.) and you WON'T cure the front sponson "hospital hop". For more than stock performance ONLY reducing the sponson AoA will get this done. TrustMe ! Tacking on aero goodies might sound good but....."

The rest is just Kabuki Theater..................

Referring back to the modification on your boat where you added wood pads and sanded them to have less angle than the stock sponson? I've been planning to get around to that mod soon. I'm just doing one at a time and testing results. It's a long and frustrating process.

[InspGadgt]

ProperChopper is right in my opinion. The AoA is everything to getting a clean setup. But it’s a lot of work to change it... I’m not going to discuss specific angles, there’s more to it that that. But getting up to speed on what makes great hydro sponsons is worth looking into... I will say this, 3.85 degrees is TOO MUCH, lol!

Is there a good website resource to learn about hydro sponson design?

[InspGadgt]

I did these mods and the UL-1 settled way down. (see vid below)

#1 : Reduced the AoA AND vented the air traps with some diversion strakes

Attachment 160194

went to a squared-off turn fin : (picture prior to altering AoA)

Attachment 160195

https://www.youtube.com/watch?v=yicE1_TfDDY

So I started working on reducing the AoA last night. I sanded the bottom of the sponsons to get maximum adhesion for the new pads I'll be gluing on and I found that the ride pads on the sponsons stock are no where near flat. They are really far off.

[InspGadgt]

Well that didn't work. Still had a lot of chine hop. Unfortunately I didn't seal the wood good enough either so by the end of the testing day the wood blistered off of the sponsons. Time to try something else.

[InspGadgt]

I finally solved the problem! I went back to the idea of a front wing and built one with a much larger spoiler on it than the last wing I tried. Took it out and was able to open it all the way up without it going crazy. Yes there still was some chine walk but not enough to flip the boat at full tilt.
Wing.jpg