10 replies to this topic

[msoccerkidm]

Hey guys!

 

It's been about 5 or 6 years since I built my last coaster and recently I was able to pull my knex out of storage and start building again. Believe it or not, this coaster is the first tube support coaster I have ever made. It will be a B&M style looper and the layout is still yet to be determined. I know I want to include a cobra roll like Hydra at Dorney park.

 

Here is what I have so far.. What do you guys think about the drop? It doesn't look quite right to me

 

 

[~stεεlspectrum~]

Tube supports are so popular these days that I almost forgot there was another option! They look good. I think the main issue with the drop is that there's lots of sharp spots. I usually go along the track, crosstie by crosstie, and adjust each one to smooth out the shaping.

The pre-drop is also pretty large, but it doesn't bother me too much that it's different from B&M.

[rgarner42]

The overall shape of the drop is good, but there are quite a few sharp spots. I find when building coaster of this size using grey rods for the large elements, and then threading grey rods through the cross ties, really helps smooth out the track and get more consistent curves. 

[msoccerkidm]

Hey guys, sorry for the postponed update. I have been working really long hours recently and haven't had too much time to build. I also had a mishap with someone in my household accidentally tripping and falling on the coaster AFTER I had finished the loop   ...so I had to redo it.

 

I have finished the loop after the drop and replaced a majority of the flexi rods with grey ones for smoother shaping. Thanks rgarner for the tip...it's definitely been a while since i've touched my knex and I have forgotten some things.

 

I also have a quick test video, I apologize the angle isn't great, it clears the loop pretty slowly at the top, but I have yet to clean and lube my trains after they have been sitting in storage for 5 years. 

 

Let me know what you guys think!

 

 

 

 

[rgarner42]

The overall shaping of the loop is great.

I think after cleaning and weighting the train it will clear the loop with more speed. 

[msoccerkidm]

Hello! I'm back with another update.

 

I added a zero g roll after the loop and started the cobra roll. The cobra roll is still work in progress so its under-supported currently. I also cleaned my trains and lubed them up and was able to get much more speed out of them, however, I don't know if I have enough momentum to get through the cobra roll. 

 

I think the issue is that the curvature is too tight and causing too much friction which is losing speed. I am able to make the first half, but can't quite seem to shape it small enough to get it over the second half. Do you guys have any suggestions?

 

 

[Gromit15]

That is one sexy zero g roll. I see that the pull into the cobra roll is sharp but you said you'd address that. Once the shaping and supports are finalized it should make it. Maybe make the entire element wider to reduce friction?

[~stεεlspectrum~]

I like the zero-g roll! It's nice that the twist is gradual instead of the way B&M zero-g's "snap" at the top.
That's a shame about the cobra roll -they're cool elements but they kill speed like none other.

[IOAgeek]

I would smooth out the exit of the zero g roll and strengthen the track to support connections a lot, at least four connections from the track to the tube support imo. Using flexi rods with tube supports also kills speed since it isnt as sturdy as gray rods are and the track sags a little for the parts where it is not supported when the train goes over it. You may want to add some gray rods in to help strengthen the track and save you some speed for the cobra roll. Is your train fully weighted btw?

Edited by IOAgeek, 13 March 2018 - 01:14 AM.

[SCM]

The problem you're having with the cobra roll reminds me of Toxic. If all else fails, lower the second half of the cobra roll a bit. If I recall correctly, that's how B&M style cobra rolls work. If that also doesn't work, then you might have to raise the middle of the cobra roll up a little bit... but I'm sure it won't have to come to that. What Gromit and IOA were saying should work just fine... but I know how picky those cobra rolls can get.

Edit: Yeah, take a look at this: 

Edited by SCM, 13 March 2018 - 05:58 PM.

[msoccerkidm]

I would smooth out the exit of the zero g roll and strengthen the track to support connections a lot, at least four connections from the track to the tube support imo. Using flexi rods with tube supports also kills speed since it isnt as sturdy as gray rods are and the track sags a little for the parts where it is not supported when the train goes over it. You may want to add some gray rods in to help strengthen the track and save you some speed for the cobra roll. Is your train fully weighted btw?

 

My trains are fully weighted and lubed. Currently I have 20 pennies under each car (4 stacks of 5). I'm going to play around with different amounts and see if I can optimize it better for speed.