Othar Tryggvassen (Orfey class)

1" diameter copper pipe 6 or 7 inches long (I forget, and it's out in the shop at the moment). I don't think going from 130# to 150# will double the number of shots it can do. Proper calculations say I need 1.5" diameter pipe (which local Lowe's doesn't have) to get to 14 shots (1 extra for good measure). With the current accumulator, I get about 5 really good shots, and 2 or 3 that I'm not sure will penetrate balsa, and several that the BB just kind of spits out. Once the pressure starts to drop, it goes QUICK! I think the present accum would be good for a 1/4 unit spurt gun, no problem at all. It'd probably do a 1/2 unit spurt also. I will test a spurt gun later on the second prototype. The second prototype will test how cheap I can do this, while incorporating the improvements I thought of after building the first one. It'll be a no-pump, half-unit gun DD for campaign at Nats when I make it to Nats next year. Bascially a torpedo that I get to reload every 2.5 minutes (DrivedrivedriveSHOOTdrivedrivedriveRELOAD, repeat as necessary).

 

Glad to hear it I hope that they are of use. I can't remember if you are going to Nats or not, are you?

 

Okay, my schweinhunden... some pics of the Othar Tryggvassen from the shop today: I had Othar hanging from a couple of strings as I epoxied in the mounts for the heavy stuff. That let Othar list from side to side as I moved things around, and showed me whether I was ballasting the ship well. As you can see, I am not using the pretty blue gearbox. I didn't have time to order 33-tooth gears, so I fabbed a wood-and-brass tubing 'gearbox' that mated up with the motor's gear. Works well.

Below is a closer (but blurry) view of the mid section. The pump wires (white and green) are now soldered to the power supply wires. Pump is always on, at least for the Memorial Day battle. Just aft of the pump is the MAG throttle, using a lil tiny Spektrum servo. Just ahead of the pump, and consuming most of the volume of the ship forward, is the gas system. I couldn't spare the weight and space for a regular servo, and a MAV-2 made the Spektrum servos cry, so I ordered a Futaba microservo that is rated at 24oz-in of torque... just enough to reliably operate the MAV-2. In testing, it is quite happy in this role. I made a 90-degree angle doohickey from piping parts, and soldered it together (along with a Clippard male-to-male connector). The inlet of the MAV screws onto this, and the wooden servo bracket is fastened to the MAV. This assembly BARELY fits under the superstructure, but it fits! The white thingy peaking out from under the MAG throttle is one of the two AA battery holders (2 AAs in each for 6V). The kick-butt Duracells are supposed to have 2-2.5AH in them, more than enough for this application. In any case, they only have to last a few minutes of runrunrunSHOOTrunrunrun and then stick it out for 2 minutes of running.

Below is another view. You can see how the gas system and pump stick up a bit. In retrospect, I should have had the forward string hole about 1/4" to 3/8" lower so that it'd be ballasted at the where the waterline should be. Ah, well. The stern one is good, and she's almost perfectly balanced port-stbd and fwd-aft. Brian K was over today playing and he was really astounded how well it was ballasted. Kind of a gratifying reaction, although I don't dare hope that the water will respond similarly oh, you can kind of see the ugly mounts I made for the gas system. Ugly but functional. No shifting loads in this baby!

Below is Othar, after the wood's been sealed with spar varnish, and after most of the guts have been reinstalled. This is before I took it down and soldered a few last connections. Almost to sheeting! The rudder and drive have been tested with the radio, and I am very happy with that! The gun was tested separately and does well, thanks to Bob's guidance (by way of Brian K). All 13 shots should be good ones.
For those wondering, the radio for Othar will be my old Airtronics VG-400; the receiver goes just forward of the rudder servo and aft of the gears.

Last but not least, a destroyer this tiny needs to be SEALED! A thin layer of pretty red RTV is being squished flat by the decks and the film clips (and other assorted things within reach). The wax paper will keep the decks from sticking to the RTV as it cures. The odd holes in the stern deck are for the gun. The ship looks bigger than it really is in this pic, until you see the clothespin there for scale
The sharp-eyed among you may see the back end of the bottom half of an I-400... This has been on a back burner for a while. But if I can do an Orfey with a pump and a gun, a roomy I-400 shouldn't be impossible! Comparing my Z-33 plans with Othar, I can say that relatively speaking the Z-boat would be a piece of cake, it's so ROOMY!

At this point, Othar weighs 2 pounds including the gun which is not mounted in these pictures (but rest assured that it's there!). I would have sheeted today, except that I am letting the RTV cure. Tomorrow on lunch I will start sheeting, the balsa is already prepared. I am JONESING for a test drive in the pool!!!!

 

Thanks guys! It's been a blast to build I will print out another set of the plans, and modify them with what I think would improve the breed, and post them here.

@Dave - the adapter end of the gas system tends to 'ride up' when there's not cartridge in it. I also will have a piece of collapsible foam on the underside of the deck to help hold it down. In these pics (upon review), the cartridge would be higher, but it won't be operationally. Good eyes! As far as ribs go, I don't think it'd make weight with too many more ribs. It's been tight as it is! If it takes a hit, it's got a pump

I am really tempted to bash another one out with no pump and a half-unit spurt gun to send to Nats with someone as a convoy hunter.

 

I know, I spent some time last night looking at schnellboot plans. I think it is possible with a spurt gun, but would require a custom-built plastic accumulator with a built in equally custom plastic valve for firing. Was thinking of a solenoid (God knows I have enough magnet wire of various sizes), or a trip-action valve that a light servo pulls on the trip, and a spring opens the valve. I have some small motors, but you'd need plastic stuffing tubes, hollow Al driveshafts, plastic props...

Hmmm... maybe worth a shot. While not on a shiplist in 1/144, I think for fun I'd give it a 1/4 unit (still hypothetical as far as rules go) spurt gun and try for 20 second speed. at 700 tons, whats the legal weight? 1.5 pounds. Dinky as heck at 9" long, 1 and 3/8" wide. I will go so far as to say that I know for a fact that I can build one that I can drive around. The tricky part is the armament. So now instead of meditating on what real ship to build next, you have no doubt planted a seed in my head that will have me ruminating on breaking the laws of physics to my will to fit enough gas and an actuator in a ship that's not on the shiplist. LOL and OMG and PBWALAW.

Positively NOT starting on it until I get Othar on the water tonite.

@Kim: thanks man I will be posting on-water shots tonite (I hope) and battle pics of Othar jousting windmills (battleships) after this weekend!

 

Yes, someone in MWC made one using an artificial heart motor. Cute lil bugger but no armament or pump. More amazing is the fact that someone actually hit it in combat!

Already started design work on the valve, although I have discovered that I'll have to build a mini lathe first to be able to turn pieces I have a reasonably new power drill that has a broken chuck which I will get the motor and speed control from. The minilathe itself should be a fun project

 

I was all kinds of excited today at work that altho work was sucking, I could escape at 5 and go home to finish Othar and test him in the pool. Sadly, it sucked worse and I wound up staying till 6:30, which cut and hour and a half off of my work time. So at this point, Othar is half sheeted, all electrical work is done, and everything works. I hope to finish sheeting tomorrow and get some test pics in the pool driving around for you guys.

 

That would be impressive engineering.

 

Breaking news: Sadly, Herr Tryggvassen will not make his combat debut at the Memorial Day battle. I got him done, and was doing radio testing prior to getting in the water, when a series of radio glitches occurred. I will be rearranging the electrics to minimize the problem, and will post test pics at a later date (probably the weekend after the battle). I will be bringing Othar to the battle for people to look at and perhaps get some feedback on design elements.