Torpedoes

[He Who Shall Not Be Named]

Twenty-some-years as a Torpedoman finally pays off.

Whoopee-doo.

Trim problems as a consequence of a launch result from only two things: 1. A variance between weapon weight and the weight of the water it displaces, and 2. Launcher/weapon gas trapped within the hull.

The net change to boat weight does not change if the weapons are aboard or not. My gas propelled weapon's displace their own weight of water. So, in the tube or out, the weapon does not affect the trim of the boat.

The momentary flurry of gas bubbles, liberated by the launcher and weapon at the time of launch is a problem. Most of the bubbles are lost out the muzzle as the weapon leaves the tube and are not the issue. It's the bubbles that get hung hung up in the void structure between muzzle opening and skin of the boat which screw up the boats trim. The other source of launcher bubbles is the small amount of gas that gets by the breech-block and actuating cylinder at the moment of launch -- small of volume but problematic if these bubbles get hung up in the bow/stern. Proper venting of the spaces around and atop the torpedo nest will get those bubbles out of there quickly.

I'm in the short strokes on the launcher. The last couple of days I modified the actuator to a larger diameter piston to present more force to insure reliable operation. Doing so now gets the breech-block from 'battery' to 'launch' each and every time, that has been accomplished. And I've eliminated the actuator piston pushrod, opting instead just to let the floating piston slam into the breech-block attachment lug, setting both the breech-block and stop-bolt into travel to the 'launch' condition.

Thank God, no need for muzzle door-breech door interlocks. No doors!

I have pretty pictures, but need clearance from the Boss (Mike, not Ellie) before I can show 'em off to you idiots. Please ... stand by!

David,

[Outrider]

My curiosity about trim was about the effects of the weight & location of the launcher apparatus as opposed to what happens upon/after launch. I guess that anything you add forward needs to be offset aft. Since the launcher isn't made out of lead, it's probably no big deal unless somebody builds up a bank of 8 tubes. (I think I remember seeing a photo of a unit set up for an Alfa that looked like a pretty imposing chunk of metal. That said, I know you have been working hard on refining your work, and that you probably wouldn't be satisfied by something that was too heavy to be of practical use.)

I suppose the amount of gas released at launch could be an issue, since the torpedos need to be pushed out with authority to get any range and speed. With a big push, it's it's easy to see how gas bubbles could get trapped in places that are normally wet. Fixes are probably easy, though, like you said. There's this thing called a drill...

[He Who Shall Not Be Named]

The boat, with torpedo tubes and related launcher items aboard, is initially weighted (location of items and fixed ballast weight) to get the center of gravity (CG) near the center of the hull, preferably aft of the sail. So, the launcher is of no consequence as it's a fixed asset aboard the hull and was accounted for during initial trim trials.

The amount of gas consumed from the boat -- don't count the gas in the torpedoes, that supply of liquid is a component of torpedo weight and is accounted for the instant back-flood water fills the empty tube at time of launch -- to launch a weapon is very, very small: just enough to move a 5/16" diameter piston, 1/2" aft; nothing that will lighten the boat noticeably. And since that gas will likely come off the main on-board bottle (used principally as a component of the gas type ballast sub-system), which is already on or near the CG, there is no appreciable fore/aft trim change. The majority of the gas evidenced as bubbles, at time of launch, is from the charge aboard the weapon. By the way, the 1/72 torpedo has a 20-second run-time for an un-boosted shot of Propellant liquefied gas. Those torpedoes make use of a nozzle with a throat diameter of a #90 drill bit.

Yeah, just punch holes in the deck above the nest(s).

I can't quantify the thrust at any point along the curve, but the torpedo thrust curve in non-linear: Big half-second burst, then 15 seconds of consistent thrust, then about 5-seconds of trail-off; If you graphed the thrust you would have a spike at the beginning, flat-line during most of the run, then a straight curve to zero -- same performance seen on actual runs of these weapons in the past. The things that are being worked on here, and have taken so long, are the issues of: launcher reliability, reduction of launcher foot-print, ease of launcher production, and simplification of launcher maintenance and repair.

Just talked with Mike. He gave me clearance to show off the work -- with a little careful cropping off of some proprietary features. Enjoy.

David,

[redboat219]

where are the pics?
Anyway, would it be possible to utilize a spring instead of gas to launch the torpedo out of it's tube?
You could utilize the water ram principle (use a small water pump to push the fish out the tube) or better still,
build something like this, http://www.fas.org/man/dod-101/sys/s...er_balloon.htm
Both can eliminate the problem of muzzle blast and gas build up around the launcher.

[He Who Shall Not Be Named]

You're folks are wrong!... THERE ARE STUPID QUESTIONS!!!!

The launcher for that ALFA is ancient history; the mechanism has been completely streamlined and made more reliable ... and smaller.

Yes, the generic launcher we're producing is sized to fit any model to the scale of the launcher. At this time we plan to sell 1/72 and 1/96 scale torpedo/launcher systems. The 1/72 launcher/torpedo products to hit the street first.

Pictured is a 1/96 system aboard a Thor PERMIT/THRESHER kit. The 1/72 ALFA system you've seen before. Today's version of the launcher is more akin to what you see with the THRESHER model.

David,

[He Who Shall Not Be Named]

where are the pics?
Anyway, would it be possible to utilize a spring instead of gas to launch the torpedo out of it's tube?
You could utilize the water ram principle (use a small water pump to push the fish out the tube) or better still,
build something like this, http://www.fas.org/man/dod-101/sys/s...er_balloon.htm
Both can eliminate the problem of muzzle blast and gas build up around the launcher.

Yeah, yeah, ... yeah! I can do it a hundred different ways. But I've taken the route I have after 20 some years of off-again-on-again developmental work in this game. The system current is the best I can do for the money you tight-wads are (maybe) willing to pay. Any other pursuit in this matter would be a fool's errand.

But, don't let me stop you -- go ahead and build a hydraulic impulse launching system. Get back to me on how that works out for ya!

Ideas are a dime-a-dozen, and there are indeed stupid questions!

Any questions?

David,

[He Who Shall Not Be Named]

Today's work on launchers -- these three used to work out mounting methodologies within the 1/72 Revell GATO and Type-7.

These differ from the last launcher in that they are shorter, lighter of weight, fewer parts, and so far have not suffered a single cook-off or hang-fire after about 30 shots each. Not bad.

One more set of identical type launchers for the Alpha-trial guys, which will firm up fabrication and assembly protocols once their critiques are in and processed.

Now ... if only I can sneak a resistance type soldering machine past Ellie, we'll be in business.

[redboat219]

why use a gas actuated piston to move the breech block aft off the torpedo nozzle when a servo can do it directly?

[pjdog]

If the cost is going to be in direct relation to how they look it's going to be expensive. Because they look great. The quality looks super.
Jack

[He Who Shall Not Be Named]

Thanks, Jack.

Yes!

Quality is good at this point, and will tighten up further as I start to employ jigs and holding fixtures during production.

David,

[He Who Shall Not Be Named]

This is how I make the gas propelled 1/72 and 1/96 scale torpedoes:

[redboat219]

What happens to the gas behind the floating piston?
Is there a connection between the cylinder and torpedo tube?
You can utilize the gas used to push the piston to boost the torpedo out. Place a corresponding hole on each side of the cylinder and launcher. The opening is positioned between the breech block and torpedo tail cone. The hole in the cylinder is covered by the floating piston in the prelaunch position. During launch as gas pushes the piston aft it uncovers the hole. Gas now enters the launch tube providing the extra push.

[Rick Teskey]

Nice avatar Merlin or is it Gandoff... the precious , the precious , must have the precious!
But seriously as a torpedo man I would like too know the loading and firing sequence on a 1:1 scale
I know go and googel it yourself you lazy squid throwing $%#@!
Once the fish is in the tube and you can skip the wire and programing stuff, is the tube closed , then flooded , then open outer doors then pressurize the tube with inner door closed then pop the cork or is the tube at fireing depth pressure with doors open then a slug of air sends it on its way ?
Thank you
P.S. there is a bit of soldering too make the launch tube with the breech block etc and not knowin the dia. of the tube used I wondered if a tee fitting is available in the correct size too replace the assembly you have too fabricate?
Or could you make a tool and cast the launch tube? Just trying too think of ways too help speed up your production time.
Rick

[He Who Shall Not Be Named]

What happens to the gas behind the floating piston?
Is there a connection between the cylinder and torpedo tube?
You can utilize the gas used to push the piston to boost the torpedo out. Place a corresponding hole on each side of the cylinder and launcher. The opening is positioned between the breech block and torpedo tail cone. The hole in the cylinder is covered by the floating piston in the prelaunch position. During launch as gas pushes the piston aft it uncovers the hole. Gas now enters the launch tube providing the extra push.

The gas behind the actuator floating piston vents around the piston and piston cylinder when its pushed back to 'battery'.

Great minds think alike, Redboat: I did just that on an earlier version of the launcher -- but instead of doing so to realize more gas pressure to eject the weapon (believe me, there is more than enough velocity from weapon gas alone), I employed the actuator gas to 'spin' the weapon in the tube; to get its rotation started to better stabilize the weapon as it passed through the destabilizing plume of gas momentarily surrounding the weapon just as it leaves the muzzle.

David,

[He Who Shall Not Be Named]

Nice avatar Merlin or is it Gandoff... the precious , the precious , must have the precious!
But seriously as a torpedo man I would like too know the loading and firing sequence on a 1:1 scale
I know go and googel it yourself you lazy squid throwing $%#@!
Once the fish is in the tube and you can skip the wire and programing stuff, is the tube closed , then flooded , then open outer doors then pressurize the tube with inner door closed then pop the cork or is the tube at fireing depth pressure with doors open then a slug of air sends it on its way ?
Thank you
P.S. there is a bit of soldering too make the launch tube with the breech block etc and not knowin the dia. of the tube used I wondered if a tee fitting is available in the correct size too replace the assembly you have too fabricate?
Or could you make a tool and cast the launch tube? Just trying too think of ways too help speed up your production time.
Rick

The weapon is normally in a rack (but, at least one warshot is tube loaded, the 'snapshot' round) and undergoes weekly checks and maintenance. To launch a weapon, it's jammed into the tube, stop-bolt engaged, breech-door shut, tube vented and flooded from the impulse tank or WRT tank (I've operated both air and water ejection type launchers), but the flooded tube is not equalized until just before launching. When commanded, we equalized the tube, opened the muzzle door and the launcher fired remotely from Control (at the fire-control station), or locally if so directed.

Yeah, I've toyed with other materials for the launcher, Rick, but nothing stands up to repeated use and handling like brass.