Mississippi 1870 Build

[bundyrap]

Hi Everyone

I'm about to start building the Sergal kit of the Mississippi 1870 as my first paddle wheeler. Altho I've been building RC planes most recently large scale electric warbirds for 20 something years, this will be only my 3rd boat. The Dumas' kit of the Chris Craft Barrel Back was the first - a very rewarding project and goes well and a Model Slipway's Al Khubar tug half way thru and a different sort of challenge in a glass hull and plastic structure.

In posting my progress here I am looking for advice and  answers to some basic (dumb?) questions as I learn. Am I in the right place?

My first challenge is adapting what is basically a static model of the Mississippi into a working RC model. This latest versions of the kit now come with the option of balsa planking the first layer instead of lime wood. Since I plan on having a painted lower hull and not the varnished planking I'm thinking I might just do one layer of planking out of 3mm balsa instead of the supplied 1.5mm balsa and glass the finish. Is this a workable alternative with a coating of resin on the inside for water proofing?

Attached are some pics of what you get. First impressions are of a very high quality kit with passable instructions. Looks like a lot of fun anyway :)

Richard

[Eddy Matthews]

Hi Everyone
In posting my progress here I am looking for advice and  answers to some basic (dumb?) questions as I learn. Am I in the right place?

Yes your in the right place Richard...

My first challenge is adapting what is basically a static model of the Mississippi into a working RC model. This latest versions of the kit now come with the option of balsa planking the first layer instead of lime wood. Since I plan on having a painted lower hull and not the varnished planking I'm thinking I might just do one layer of planking out of 3mm balsa instead of the supplied 1.5mm balsa and glass the finish. Is this a workable alternative with a coating of resin on the inside for water proofing?

I haven't built this model, but the normal paddler problems are those of top weight/stability and wether the hull will be of sufficient draught to support it and the necessary drive gear, RC gear and ballast etc.

Balsa is a perfectly good material to use on a hull, but it must be thoroughly waterproofed. I'd suggest a coat of epoxy resin inside and out before painting.

The hull on all sternwheelers is very shallow, so I'd be looking at increasing it's depth by 1/2" or so to support the items mentioned above. Most people will never know it's been altered, and you have to be practical...

Finally (for now) I'd also look at how you can save weight on the superstructure - By replacing the supplied materials with thinner stuff, or using plasticard maybe? Are the fittings resin, white metal castings, brass? Again, look at replacing anything that is heavy with a lighter alternative. The top weight is always going to be one of the major problems with this model, so you should look at saving weight wherever possible.

Attached are some pics of what you get. First impressions are of a very high quality kit with passable instructions. Looks like a lot of fun anyway

Richard

It looks very good quality from the photos Richard - I wish you every success with it...

[Eddy Matthews]

Anyone else with more experience of sternwheelers care to make a comment? I've only built two sternwheelers, so I'm no expert on them, and I'm happy if you want to say I'm wrong with the comments I've made so far...  :wink:

[derekwarner_decoy]

Hi PD's & as Eddy says..... welcome Richard to the only & :no1 Paddler WEB site in the world

If I could humbly   suggest, just spend as many hours as you have available reading our PD postings........ you won't regret the hours & ask as many questions as you wish... someone from our world wide group will offer constructive comment

Oh BTW PD's...... Richard is from our northern OZ city of Bunderberg.... which is also the home of that famous OZ drink BUNDI+Rum   which I believe is EXPORTED   to most or many Countries.... but possibly not yet to SCOTLAND  :music  :rant - Derek in Wollongong.... just down the  :arrow:  :arrow:  :arrow: east coast by some 2300 km from BUNDI

[Peter Webster]

David ,
           Welcome to the group, great to see another Aussie joining this great paddler hobby, as regards to weight  saving and waterproofing balsa I have been using balsa for a few years now and found the about 5 to 6 coats of nitrate dope, progressively thing and rubbing down between each coat will achieve a very waterproof hull and is cheaper than epoxy resin. Don't forget to download Skype so all us Aussies can chat and plot together. I hope I spelt the boat name right.
Peter Webster
A bit further south than Derek

[bundyrap]

Hi Everybody

And thanks for the replies.

I like the idea of making the hull 12mm deeper to help cope with the weight of the working bits to be added. Easy to do at this stage - see attched pic. Thanks Eddy.

I like the varnished planked wood look but in moderation so with all the planked decks. windows and doors I'm going to do a plain black hull. My warbird heritage is coming thru here but planked 3 mm balsa with 1oz cloth and epoxy with a brushed coat on the inside is the plan.

Superstructure on the Mississippi is all wood and some brass. Light ply frame with vertical planking and laser cut details is the order. Doing it out of plastic would be lighter but not a whole lot for the trouble so I might stick with the kit's super structure as is. Besides I like working in wood!

Next looming Rc question is the rudders as supplied. Wood with wooden dowel running in brass tube. I haven't fully gone in to this yet but it seems unusual. Is it sound?

Thanks for the input guys
Richard

[derekwarner_decoy]

Hi PD's - Bundyrap wrote

Wood with wooden dowel running in brass tube

Richard - if it is intended to contact water, the wood will swell  :sob & you wont't be happy :rant as it will sieze  

All/most Model supply shops have the American range of K & S metal tubes, flats & other sections - eg., a 1/8" OD tube [0.125"] runs perfectly in the next telescoping tube size being 5/32" OD - the differing profiles of round, square, rectangular, flat, plate, angle...... & with a bit of thought compliment each other perfectly to construct whatever

Soft soldering is not a difficult   task & brass solders easly, naturally does not rust & can be polished to a   shine.... so much you need & the running surfaces can be lapped with Sandy's favourite drink BRASSO   - Derek

[bundyrap]

Hi All

Pics show my progress to date. The hull is planked and glassed, lower deck is on and planked, the supplied wooden rudders and arms have been replaced with brass ( thanks Dereck) and the lower storage and engine rooms are nearly finished.

I'm still keen to have a go at making working Pitman rods with a belt drive as plan B. What rpm should I be aiming at for a sternwheeler? The MFA/Como Drills ad is suggesting their 810:1 gearbox giving 19 rpm on 12volts is ideal for sternwheelers but would have thought the 148:1 ratio giving 106 rpm would be closer to the mark.

My next challenge is to split the second level deck horizontally so as to make the upper levels removable to allow access to the workings. I have just finished a HobbyCNC 3 axis cutter so its first job in anger will be to cut a copy of the second level deck shape. Could be done by hand where is the fun in that!

Richard

[Eddy Matthews]

It's looking really good Richard - Nice work!

I'd go for the 148:1 motor/gearbox, 19RPM may be about right for the full size vessel, but it's never going to work in a model...

[towboatjoe]

For a model you're going to need  to be able to turn the wheel around 100 to 150 rpm max. It sounds excessive, but you'll need it to fight cross winds.

My Verity will turn over just a little more than 100 rpm and it has a hard time with wind. It's a heavy boat too, but with shallow draft and three decks of cabins, the wind loves it.

With such a beautiful boat I would paint the hull white.

[David Allinson]

Hi there Richard.
Regarding the speed of the paddle.
 As Eddy correctly says 19RPM ain't never ever going to work on a model!
How fast do you want it to go in say feet per minute?
Take the circumference of the paddle in feet.
Assume say 20% slip (X1.2) between the water and the paddle when cruising.
 1mph = 88 ft/minute.

Circumference is PI X D
Say paddle is 6" dia. 3.142 X 0.5 = 1.6ft
Speed of ship required say 2mph
RPM = 2 X 88 / 1.6 = 110
Correct for slip 110 X 1.2 = 132 RPM required.
(Say 150RPM to be safe for the above case!!)
This way there shouldn't be too much guess work about what gearbox to use.
All the best
David



 It's looking really good Richard - Nice work!

 I'd go for the 148:1 motor/gearbox, 19RPM may be about right for the full
 size vessel, but it's never going to work in a model...

 --------
 Regards
 Eddy>

 

[bundyrap]

Thanks for help Guys :)
 
I'm starting to look at ways to make scale, working Pitman rods to drive the wheel.  The kit comes with a 6mm solid brass shaft and plain bearings for the paddlewheel with everything being glued to the shaft.  
 
So two questions at this stage - are the plain bearings adequate to cope with 150 rpm workload and is glueing the wheel frames and cranks to the shaft the best way to go?
 
My feeling is the bearings should be alright but I'd be looking at soldering/screwing brackets and cranks to the shaft. Any advice?
 
Thanks as always
Richard

[derekwarner_decoy]

Hi PD's & I assume Richard, the bearings you mention are as per the snap....

1) I agree, soft soldering is far better than any form of gluing when brass is concerned...you may need to make a compromise somewhere as you will need to secure brass to wood... a brass disk the size of a ten cent coin... soft soldered to the paddle shaft but pre drilled for 10 BA brass metal thread screws?.... around the OD & secured back to the wood

2) In a perfect world we would never design & use the same materials in a bearing application... having said this... brass on brass @ 150 RPM would be fine with acceptable lubrication.... considered pre drilling a 2mm diameter hole at the 12.0 o'clock position in the bearings :?: - from there you could inject   a dollop of RUBBER grease prior to each steaming/motoring/paddling :  :shock:

This rubber grease will not disolve @ the speeds/temperatures you will experience and will not leave those   tell tail rainbow polution drops in the water

You are doing a great job.   ...................Derek

[bundyrap]

Hi Derek

Would proper stainless steel bearings such as from Stock Drive Products  ( https://sdp-si.com/eStore/ ) all round be the better option?

Thanks
Richard

[derekwarner_decoy]

Hi PD's & funny you should ask that Richard.............I initally installed 1/4" ID Sintalite bushes to PS Decoy in Y2002, but found the tension deflection in the 1/4" paddle shaft [when electric & belt driven] not to my liking  :sob

So with the current refit     to steam, I purchased four X SR3C-ZZMC3 [3/16" ID X 1/2" OD] stainless steel roller bearings (ZZMC3 = also S/S shielded] from the same https://sdp-si.com/eStore/ ) source & @ $4.80 AUD each was very in expensive

If you have the design/means/location of floating your paddle shaft in S/S sealed roller bearings, they willl out last you by 1000,000 years    


Is there never any end to PD modeling :?:  :arrow:  :  - Derek