Lulonga - My first paddler build.

[jelley_baby]

Hi Bert, I agree that sealing a wooden hull is probably easier than the ABS plastic one, I injected Polyurethane from an spray can obtained at the local DIY into the chambers and you would not believe how much of it came out into the main chamber through the smallest of gaps. At least I now know that even if water gets in she will still float. Watching her starting to capsize about 6 feet from the boating lake edge is not an enjoyable site I can assure you. Graham

[LARRY W]

 Hi Bert,
         Go easy on the expanded foam ,     expands to three times it volume ,
          you say you are going to skin the out side of hull , so why don't  you coat the inside of hull with resin ,
      i do this with all my plank on frame models all nice water tight  , and makes a very strong hull , cheers Larry....

[15Bert]

Graham, I don't fancy the sinking feeling so I will put some foam in the outer compartments.

I will be cutting the  foam from blocks, I've never had any luck with that expanding stuff, too messy!

That's a good thought with the resin Larry, I'll do that.

I hope to do the skinning later this week if time allows.

Bert

[steamboatmodel]

Graham,
Be care full with the expanding foam. I used it in a model once, built the model in the winter, injected it in and trimmed the what I thought was all the excess off. I then finished up the model, during the following summer the model was on display at a show out in the sunlight. To my dismay the deck started building and then cracked, the foam raised the deck up about an inch. On investigation and repairing of the model I found that some of the foam in the very center had not expanded once the foam on the outside had sealed it off and was still sticky once it was exposed to the air it started to expand. On talking to the manufacturer I found that the foam would expand up to five times its original volume and that it should not be applied so that the expanded volume was any thicker then 2 1/2" and that if it was exposure to high heat could cause the foam to crack and the uncured foam trapped could then expand. They claimed that it was all in the instructions and any damage was not there fault. 
Regards,
Gerald.

[15Bert]

I did some sanding on the bow laminations tonight, it's roughed out. I will finish sand it tomorrow if I get some time.





More to come

Bert

[LARRY W]

 BERT ;
 Looks good ,  you will have bulwarks coming up from deck level ,
 cut card templates at this stage to get the idea of bow flare , also there is a rubbing strake at deck level ,
      cheers Larry...

[LARRY W]

 Here is a bow picture..Larry..

[15Bert]

I've been away for a couple of weeks, one of which I was in Kent where, amongst other things we took a short trip on the 'Kingswear Castle' and very good it was too.

Now I'm back and I want to get on with things but I'm a little stuck at the moment trying to decide on the electric motors I need. I want to decide on the  the motors now so that I can be sure it will all fit before the main deck goes on. The write up in the mag doesn't really help, could anyone suggest what power will be needed to drive the paddles?

Bert

[LARRY W]

 Hi Bert,
          fit motors and drives plus paddles before, deck works , as for motors mfa geared was used on plan ,
         or some one on the site might suggest some thing different , have now paddles or motors in mine at the moment ,
      waiting to purchase when i have saved up , on a pension so bit tight for money , Larry......

[15Bert]

After a bit of thought (not much!) I have gone for a second-hand set of 1:16 tank drive motors and gears from the 'bay.

They look like they may fit, and hopefully will be around the right speed and power. At about five quid including postage it won't break the bank if it's no good.



Hopefully they will turn up in the next couple of days so I can get on with it.

Bert

[LARRY W]

Hi BERT ,
            They look OK but what paddles are you going to use , not expert on drives , so gearing asto be right
  may some body on the site may help ......Larry....

[derekwarner_decoy]

Hi PD's......... ....Bert you are looking at a nominal 150 RPM no load speed on the paddle shaft...if your geared drives produced 250 RPM then with an electronic speed controller they would be suitable

With high speed motors and suitable gearing ...the current consumption will be relatively low but needs to be checked to ensure the speed controller can cope

Gear train [mechanical] noise may be an issue 

You could always work backwards & find out what model tank they were from & see what type of speed controller it had

Keep us posted.......Derek 

[15Bert]

The tank drives turned up today and they look pretty good to me.
It's difficult to measure the speed with my aeroplane tacho, but at six volts it looks to be about 200rpm, I can gear it down a bit through the chain or belt drive to the paddles so I think it's going to be ok.

The current draw at six volts is less than half an amp even when loading it up by trying to stop the rotation with my fingers so no problems there either. I can't stop it or even slow it down significantly with my fingers so the power should be enough. It does sound a bit puny at three watts per paddle though. I'm more used to 350W and more with my model aircraft but I guess that's a totally different scenario.

They are a little noisy but if I mount them on rubber I think they will be quiet enough, time will tell I guess.

Bert

[derekwarner_decoy]

Hi PD's......Bert with that low current draw [two x 0.5 amp unloaded] ...an inexpensive ESC capable of handling say 5 amps will certainly suffice

You are correct that seemingly lower input power at geared down speeds can produce HUGE torque values that would break a finger so ...... ...so best left at that ....Derek

[15Bert]

I have ordered two of these, they are rated at 10A 4.8 - 8.4V



With postage from China the two come out at £13.28.

I will need to sort out pulleys and belts to take the drive to the paddles, but that can wait until the construction has progressed some more.

The paddles will be home made, I can't afford the Graupner units.

Bert