Hospital Hop...how to stop it?

[NativePaul]

I've got it turned back as far as it will go...it is still lifting the boat.

So make it go back further, the bend/curve acts like a hydrofoil and if the front of the bend is higher than the back it will give lift in a straight line, and if the back is higher than the front it will give downforce in a straight line.

The only other alternative is that it is not going in a straight line, but turning left, which will also make it ride up the turn fin. Is your rudder set straight? Is the strut straight from left to right? If not you could be crabbing sideways whilst tracking a straight course.

[properchopper]

From the Vault (referring to the day Jay mentioned) :

DSC00820.JPG

[InspGadgt]

So make it go back further, the bend/curve acts like a hydrofoil and if the front of the bend is higher than the back it will give lift in a straight line, and if the back is higher than the front it will give downforce in a straight line.

The only other alternative is that it is not going in a straight line, but turning left, which will also make it ride up the turn fin. Is your rudder set straight? Is the strut straight from left to right? If not you could be crabbing sideways whilst tracking a straight course.

Boat is trimmed to run straight so the rudder should be set straight. Strut looks fine other than it is missing the bushing that it is supposed to have. The turn fin is actually angled down slightly...back is higher than front on the big bend line.

[InspGadgt]

you did this to decrease the angle of the sponsons ----- yes


to eliminate the step in the sponsons. ----- NO

Interesting...so our running area is not as smooth as yours is in the video. Will a lower sponson angle help in rougher water?

[properchopper]

Interesting...so our running area is not as smooth as yours is in the video. Will a lower sponson angle help in rougher water?

most likely. If it tames down the tap dancing in smooth water it should have a similar effect in "rougher water". I don't run hydros in rough water fwiw.

[InspGadgt]

most likely. If it tames down the tap dancing in smooth water it should have a similar effect in "rougher water". I don't run hydros in rough water fwiw.

I wouldn't if I had a choice :) We only have 1 fresh water source on the island and that's too small for these speeds. The alternatives are both brackish water and it would probably be more classified as a river than a lake.

I ordered the Hug airfoil from OSE so I'll be giving that a try first. After that I'll be working on an air dam similar to you and possibly the sponsons as well.

[InspGadgt]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.

[MADRCER]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.

You can see the bushing in the picture. It's in the stuffing tube....Nothing wrong with that. Pull it out, free it up so it floats inside and trim the tube a little then let her rip. Order another one if you have the old style because the new style has larger holes for better lubrication.
https://www.offshoreelectrics.com/pr...od=dh-aqub8003

[InspGadgt]

I'm not sure that's the bushing...my understanding was the bushing was supposed to come up to but not connect with the stuffing tube. If that is it...it's pretty stuck on...i don't think i'll be able to free it up. But when I looked at it it just looked like 1 piece with a ring grooved in.

[MADRCER]

I'm not sure that's the bushing...my understanding was the bushing was supposed to come up to but not connect with the stuffing tube. If that is it...it's pretty stuck on...i don't think i'll be able to free it up. But when I looked at it it just looked like 1 piece with a ring grooved in.

I'm sure it's stuck because most are just crammed in there. It'll come out just work with it. Throw it away and get the new version.

[InspGadgt]

The new version?

[InspGadgt]

I don't know...it is really tight and the thickness of the tube wall is the same as the other end. If it is...it is really stuck in there...I don't think it is coming out.

[properchopper]

So here's my strut with stuffing tube...as you can see I have no prop bushing. The stuffing tube just goes all the way through my strut. If I had a proper strut I could use some prop angle adjustment to help calm down the hopping. I'm hoping customer service will replace it with a proper strut but with them in the middle of a transition to Horizon, things have been moving a little slow.

Mr. InspGadgt,

This may not sit well but because you need some truth therapy I'll give the best of my knowledge and experience to get you some actual workable solutions -

#1 - You DO have a prop bushing. It's inserted into the end of your stuffing tube. This is standard operating procedure for about 80% or more of all rc boats - particularly those in the IC realm. The alternative is to replace the brass sleeve bushing with lead teflon bushings. They need more frequent replacement so the RtR boats often don't come with them.

#2 - it seems (from your picture) that your stuffing tube is pinched at the point it would enter the strut. This may be capturing your brass bushing making it hard to remove. Get it OUT somehow. If it doesn't turn freely chuck up the back end in a drill, smear some toothpaste (for lapping compound) on it and pull the trigger. This should soon allow it to spin freely. Clean off toothpaste when done.

#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.......

#4 - A stuffing tube extending all the way through the strut is a very common way of how it's been done for eons. In fact you CAN adjust strut angle with a little pressure on the strut - it'll bend/flex the slight amount you may need for a minor adjustment.

BUT

#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...

Realize that this is a hobby-grade model designed to perform "as delivered" and runs beautifully in smooth water with the supplied prop. Once you go for more performance or run it in bouncy water mods need to be done and expectations carefully thought out.

Enjoy

Tony

[InspGadgt]

Ok thanks. I've been trying some penetrating oil to try and get it to loosen up so far but no luck. It is so tight if I chuck it in a drill I think I would damage the stuffing tube too. I guess I'll try heating it next and see if I can get it to free up.

[properchopper]

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