TopSpeed 2 handling issue

[OtisHelmke]

Afternoon all,

I finally got my Topspeed 2 in the water the other day and had unexpected results that I don't understand. I built and balanced it to the instructions. In the straights it runs pretty well, no bad habits, doesn't porpoise, sits about right on the water at full throttle, doesn't seem to want to submarine or blow over. Unfortunately in the turns it is a different story. Once it starts a turn it begins to porpoise badly and if I push the turn enough it is trying to hook and spin. I was not using the turn pads but have since installed them but not tested it again yet. From my reading I gather the TS2 is not the best handling hull in this series but since I have it I want to learn what it has to teach and get it running as well as possible. Past experience with my HotShot Sprint showed porpoising in the straights and it settled down nicely in the turns. I added some nose weight and that settled that boat down very nicely, it is one of my favorites. So I'm mystified as to why the TS is hopping through the turns and settling down when it runs straight. I don't know how much speed this must be costing me but it can't be right. Engine is a K&B .21, no pipe, 30% nitro, not getting the max rpm out of the motor for now, just going throug a run in process but still getting probably 35-40 mph for now. Hoping for 50. Bottom line is my VS-1 seems to be faster for now. What can I expect from the TopSpeed? I like it's looks and hope it will imporve. Thanks.

Rick H.

 

[Jerry Dunlap]

I would suggest you try lowering the engine slightly to see if that helps in the corners. With a lower prop depth, you should be able to slightly increase the positive prop thrust angle. The "turn pads" should be installed on the TS2.

50 mph with a K&B 21 on 30% is probably not obtainable with the TS2. My TS2 with an O.S. 21/50% fuel would run 43- 45.

JD

 

[OtisHelmke]

Thanks Jerry I will try that. Turn pads, I've heard them called several different things, don't know what the correct designation is but they are on there now. The directions are ambivalent about their use. I'll see what I can get out of her.

Rick H.

 

[Jerry Dunlap]

Thanks Jerry I will try that. Turn pads, I've heard them called several different things, don't know what the correct designation is but they are on there now. The directions are ambivalent about their use. I'll see what I can get out of her.

Rick H.

Rod Geraghty was the first modeler to add the forward ride pads to a model tunnel boat. I've always liked his name for them - "Stumble Blocks."

JD

 

[happybradboating]

I would say you will never get rid of the hopping completely. It was a few years ago when the nationals were in Colorado that we asked Jerry Dunlap about the problem and gathered that in part the mold had some type of problems that caused some of the handling problems. I have tried everything on mine and never completely got rid of the hopping.

My next plan is stripping everything off the boat and throwing it in the trash can!

 

[Duck899]

Radar gun does not lie, Tunnel hulls are some of the most interesting boats to get to work properly. They are so much more dependent on air flow under the hull and over. And, then you have the hydrodynamic equation. The water spray that occurs in the tunnel.

I would insure that the ride surfaces are flat and true with edges as sharp as you can get. Then, wet sand the entire bottom with 800 grit wet/dry paper. This includes inside the tunnel so the water does not "stick". Then go to work with prop height, angle, prop, balance, etc.

 

[shoboat]

Otis,

I found the TS-2 to be rather propeller sensitive. I had mine up to 53 MPH on a

1440 B/C with 3.00" of cup on a Kensill prepared OS watercooled motor. I just had

to keep tucking the motor under the boat to get rid of the hopping.

Have Fun Testing Otis,

Mark Sholund

 

[wayne middlemiss]

^^^^^ fully agree with you being prop sensitive , found that out whilst using the os plastic prop when breaking in ,it wouldn't turn, but x440 all good.

 

[Alan Elzer]

How do you tell the difference between the different versions of the top speed hulls?

 

[Dan Pralle]

Top speed 2 has stepped ride pads

 

[OtisHelmke]

Mark what do you mean by tucking the motor up under the boat? Lowering it or trimming it forward to keep the nose down? Something else? It's funny how different boats in the same class work so differently even from the same designer. My HotShot Sprint hulls in 3.5 and 7.5 are among my favorites for some reason, not the fastest but I enjoy driving them. The TopSpeed at least early on is not reaching out and grabbing me. I have hope for it yet. I have a Cobra ready to test and right now my VS-1 is easily my favorite and best running hull.

Rick H.

 

[Robert Pickard]

You will like the VS1 more then the Cobra now if you get a Vision that will be your favorite

 

[shoboat]

Rick,

I just kept angling the motor closer to the transom of the boat.

The height of the motor was easy to find what the O. S. Motor

liked right away, the O. S. With no shims and the crank with a

Turbo cut on the crank really turned up the RPM. It was fun

back in the day.

Thanks For Reading,

Mark Sholund