NL2 Riverview Bobs

Hey everyone and Happy New Year!

In this thread I'm going to be recreating the Riverview Bobs in NL2 using FVD++ for the trackwork. I'm using the blueprints in the back of Derek Gee and Ralph Lopez' book "Laugh Your Troubles Away". This will be a bit of an adventure for me because I haven't used FVD++ before. Anyway, I spent some time this evening punching the ledger height and bank angle numbers into a spreadsheet.

The idea behind the spreadsheet is that all the figures will be easier to read. In addition, since FVD uses metric and the blueprints are in imperial, I'll have both measurements side by side so I can match up where I am in FVD with where I am in the blueprints. The bad news is I'll have to convert all the bent heights manually. I have a nasty feeling that I'll need to calculate the radius of curvature for all the straight hill peaks and troughs as well as the turns, too.

So far I've copied over the figures for 180 bents. That's the section from leaving the station to the entrance of turnaround 3 (TA3), the lower fan turn.

A note on the height of the lift: there is an error in the blueprints. About halfway up, the heights change from 4 foot increments to 3 foot increments, resulting in a stated maximum height of 54'9". This cannot be correct, because the height of the subsequent fan curve (TA1) is 51'5" and the train would not make it over the crest. Gee and Lopez note in the book that there are several blueprints in existence with different height marks on them. One is as high as 77 feet. I wrote to them and Derek said that they've done some more research since publishing and he now believes the final height was 64'9". Derek also pointed out there was a 10 foot mount underneath the crest of the lift hill, so the figure represented the height of the bent itself and not the height of the coaster above grade. I've adjusted my figures in the spreadsheet accordingly. The subsequent three bents are a bit suspect too, but I'll fix them later once the rest of the ride is in place.

No pretty pictures tonight, but I may start playing around in the editor on the weekend

[mkingy]

Great stuff, a hopefully perfect track recreation in the works! It's great to see you got a response back from the writers to clarify the blueprints too.

I look forward to seeing your progress.

[Coasterkidmwm]

Given this used to exist in the middle of Chicago, I think you can guesstimate the ride height relative to everywhere that doesn't have the 10ft pile of dirt under the ride. Chicago isn't known for terrain.
Should be a neat project through even if you don't get 100%. My mother used to love that ride, but for whatever reason now a ferris wheel makes her sick.

Coasterkidmwm wrote:

Given this used to exist in the middle of Chicago, I think you can guesstimate the ride height relative to everywhere that doesn't have the 10ft pile of dirt under the ride. Chicago isn't known for terrain.

That's a good point and I'll bear that in mind. Thank you

Interesting tidbit: In the blueprint Church intended there to be a tunnel from the curve out of the station to just before the curve onto the lift hill, which does not appear in any photo I've seen. Maybe when I finish the track I'll add that in for historical (in)accuracy!

Hats off to this project. You will make an impressive attempt.

I've completed the spreadsheet except for the metric ledger heights. There are 332 bents in all. This figure may be slightly inaccurate because on the plan the station does not include every bent height.

Speaking of inaccuracies, the blueprints in the book consist of an aerial plan with the bent heights and turn radii marked, and a side profile of what the hills would look like if all the curves were unwound. On the side profile, there is a dip between the exit of the lower front turnaround (TA4) and the start of the next hill. On the aerial plan, this section is flat. I've looked over the Bobs' POV on YouTube and this dip was present on the real ride, which suggests that either the side profile comes from a more recent set of blueprints for the coaster, or that Church forgot to amend that stretch of track on the aerial plan when he corrected all the other mistakes. There's quite a few scribbles where he's crossed out previous height marks, as well as the following explanatory text in Church's handwriting:

"I have checked over sheets #1 to #8 inclusive. I find the ride safe, and that it to the best of my knowledge, complies with the [unreadable] requirements and approved [unreadable] corrections [unreadable]."

Tomorrow I'll fill in all the metric measurements and then start work on the actual building. If FVD++ is how I remember from my brief play last July, every time I change the up/down pitch of the track I need to tell it what the radius of the curve is, or for lateral curves what the pitch angle is. I have no idea what that is for a gently sloping brake run. I'm guessing there's going to be a lot of paperwork as I draw and then measure the slope angles of all the curves - the plan states the banking figures but not the pitch. Oh well, it'll be worth it in the end.

For those who haven't seen the YouTube POV, here it is. Hold on tight!

https://www.youtube.com/watch?v=H0P6_FAS6TM

[herman116]

That POV looks pretty exciting for such an old ride. Good luck with recreating it!

[Paradox]

Damn this looked intense.

Yeah, by all accounts it was. I've seen off-ride footage which showed the train to be nearly as fast as in the video. It'll be interesting to see what the final forces are. I read somewhere that Fred Church was fond of laterals, and the maximum bank angle on the aerial plan is 56 degrees.

[mkingy]

I mean even despite the fact the old film is being run slightly faster than reality it would still pack a punch!

[Coasterkidmwm]

This is why I don't understand why my mother won't go on a ferris wheel now when she used to ride that thing. It looks like it was brutal relative to today's rides.

Yeah, exactly. I reckon it would give Voyage a run for its money, and that's like most coasters on crack anyway.

^ Classic woodies appeared to pull over 4, 5g's at the bottom of each hill! I don't think that they had official g-force limits. Bumpy feeling everywhere compared to today's "calculated" coaster transitions.

Spreadsheet complete. Now just working out how to get proper geometric turns in FVD.

Well, I'm calling it a night. I've been wrestling with FVD++ and I can't seem to get it to do what I need it to do.

Attached is a bad photograph of the high front turn (TA2) section of the Riverview Bobs blueprint. As you can see, all along the curve of the turn are height marks where the bents go. The figures in circles are the degrees of banking, and the radius is marked as 30'. In order to create an accurate turn in FVD++ I need to be able to specify the radius, the length of track and the height and bank angles at the start and end. That would enable me to create the turn in stages. The other problem I'm having is with the straight sections where it seems the only thing I can tell it is how long it should be, but not the start or finishing heights. Am I trying to do the impossible? Is there a better way?

[Coasterkidmwm]

Perhaps you could just make the turn the correct angle at the start and then manually move the vertices (Y axis in the editor when you double click them) to get the angles "close-enough" if you have no other alternative.

Coasterkidmwm wrote:

Perhaps you could just make the turn the correct angle at the start and then manually move the vertices (Y axis in the editor when you double click them) to get the angles "close-enough" if you have no other alternative.

Thanks. That gave me the idea that going back to Newton 2 was the answer because it allows you to make several 15 degree sections of a curve and adjust them individually to create the overall 180 degree curve you want. I'll have to play around a bit with the roll and direction sliders because apparently roll in my mind does not mean roll in Newton 2's mind; i.e. if I have a 180 degree curve and I set the roll at the start to 45 degrees, Newton 2 rotates the entire curve so the exit is lower in height than the start, as opposed to keeping the entrance and exit heights the same and simply tilting the rider 45 degrees (Church's numbers relate to the angle of the rider).

ETA: Will have a play tonight and post some pictures of my rough attempts

So I had a play to try and get the lift hill and first drop correct and...it didn't go so well. You can see from the photo that the lift crest is completely screwed up and not smooth at all. I'll post about that in the NoLimits forum. The main points though:

1) Vertical Gs did not go into the red. They did reach 4g in the back seat at the bottom of the drop, but I blame this on my bad skills as Church's lift crest, drop and pullout wasn't as steep and would have resulted in gentler forces.

2) The lift hill angle is correct.

3) It was not a tall coaster.

4) Max speed in the sim was 39.6 mph with the lift and friction set to the defaults, but it feels a lot faster.

The crest of a lift hill should be about 3 times wider than you shaped. And as for the bottom of this drop you can make that part intense as long as you don't see yellow g's.

Happy recreationing.

[Coasterkidmwm]

Yeah lets just say I'm glad you recognize that lift crest isn't right lol.

Just curious, since you know the height of every single bent, I assume you can figure out the spacing too, is it possible to build the structure first and then the coaster? I feel like this might be easier than using Newton 2 or FVD++, but I could be wrong

[Coasterkidmwm]

That is a fair point ckidd.

CKidd wrote:

Just curious, since you know the height of every single bent, I assume you can figure out the spacing too, is it possible to build the structure first and then the coaster? I feel like this might be easier than using Newton 2 or FVD++, but I could be wrong

Fair point, I'll give it a go. It may be easier for me to make all the sections horizontal in Newton 2 and then use that to guide the placing of my supports.

Okay, I used a combination of your ideas. I made a 3.048 metre (10 foot) piece of straight, level track and saved it as an element. This is the spacing of the bents on the straight sections. Then I strung 30 of them together and raised the heights every 3.048 metres to match those marked on the blueprints. Don't worry, I used the same units for bent spacing as for height! Deleting the superfluous nodes then gave me the perfectly shaped lift hill and drop. Wood magic was used for the supports.

Ahhh, That's better!

Points to note:

1) Positive vertical Gs were safe - with default friction it reached exactly 3g at the bottom of the drop in the back car, and 2.5g at the front. The back car got 0.8g as it was whipped over the crest of the lift.

2) Top speed was 40 mph. I threw in a straight section before curving around to return to the station and it hit 42 mph, so there's potential there.

[Paradox]

Looks like you are off to a good start. A couple years ago Trackwalker made a recreation of the same ride in NL1 here which you can use as a reference if you would like to.