Continuing/finishing (?) a Revell 1/72 type VIIC from another user

[Reckless]

okay decided to give a new servo a go, get this thing running and get some enjoyment before flipping stuff around. (and a big regetta from my old boat group in August .. and I wanna represent das boot! hehe..

so... plan A




and if that doesn't work... theres always ...
plan B

[Reckless]

avera if you search SAS (semi aspirated system) on this forum you'll see what we are talking about... it replaces the gas system and allows you to use some of the SD's internal air to start the ballast blow till your snort tube/snorkel can broach the surface and pull fresh air.

it's something Dave has been working on and finally got around to actually doing his own subs and sea trialing them so he can make production retrofit kits.

mines actually been in the water... but due to things both my own doing and previous builder .. I'm at a compromise stage now ... I just need to pick a direction ;)

[Avera]

Hi Reckless,

I too am in the process of building my VII sub. Current configuration is with just the ballast tank to control ascent and decent (waiting on repairs to the blow valve). I have ordered the LPB to be the primary system with the ballast tank as backup. I am not familiar with the SAS or its pending conversion kit production. Is this something to replace or complement either or both ballast and LPB systems? In the meantime I'll keep searching for information.

Andrew

[Reckless]

that's entirely possible too.. I'll have the space for it loosing that servo... both would basically be on the same channel just either side of it but to make it worthwhile and not over complicating I'd have to be able to use the existing manifolds and tubing...

can the caswell LPB pumps pump through each other? or does the internal diaphrams seal? if they can pump through each other it would be easy... combined with the SAS conversion ...

Dave... can the pumps pump through each other? .

and... would a production SAS convert for the type 7 include the flapper bit for the snorkel?


I don't mind putting my aspirations of having this thing running on "hold" if it means waiting for a production SAS kit and simplifying the operation for my own use. ... I mean hell it's taken me this long ... it's not going anywhere ;)

[redboat219]

can the LPB pump run in reverse? aka pump air in.. pump air out..

try looking for Oztruck's 1/72 I-25 conversion. http://forum.sub-driver.com/showthre...I-I-25-in-1-72.

He used 2 LPBs, one to blow ballast via snort, one to vent the tank.

[He Who Shall Not Be Named]

No, sorry. It's a positive displacement diaphragm pump -- fluid moves the same direction, regardless of moto-pump direction. Hang in there, the SAS conversion packages will be available soon. The pump and servo remains as is, the retro-fit will be an easy matter.

For some reason I can't post pictures here -- trying to fix that. Want to show you what I did to convert my Type-7 and GATO to SAS. Easy.

Hey! Keep thinking outside the box. I do. Many a wrong turn, but we eventually stumble onto a practical solution to a problem.

David

[Reckless]

Dave... I have a really stupid question.... can the LPB pump run in reverse? aka pump air in.. pump air out.. just thinking (maybe over thinking to simplify my specific needs/issues) .. that I've already somehow figured out how to grenade the gas system, and mysteriously melt a servo... maybe just ridding my SD of that whole system and putting a mini pump controller in would work better for me.

I already found out that the LPB pump will sink the sub rather well when I got my hoses backwards.. and give a little visual indicator the tank is full (although on mine it would be an unrealistic spurt of water out the periscope LOL )

would also allow me to move the snort manifold to a better location to get under the tower and I won't have to have the subs deck lifted a little to clear it

[He Who Shall Not Be Named]

A loooonnnnng screwdriver and looonnnng hemostat does it for me. CA the screw head to the screw-driver tip makes life a lot easier.

David

[Reckless]

the servo's motor itself was/is fine.... (infact it'll probably end up on a CCG rigid hull inflate I've got sitting on the side for rotating radar)

I haven't had any time to get back to the SD to reinstall the new servo.. and I've tried it in my head a couple times... frankly getting that ******* in there proper is gonna be a PITA (you've seen the pic.. i've got big ole beat up mechanic ham fists)

[He Who Shall Not Be Named]

OK ... the case got hot around the motor. Pop the back-plate off that sucker, and look at the brushes. Are they melted?

[Reckless]

okay... I haven't been on my laurels or asleep at the switch... just haven't been able to get back online for pictures and such..

Dave.. nope SL8 (you reprogrammed it to your freq when you had the SD for a rebuild)

onto the pictures...

the pinion on the servo motor is that little blob on the edge of the bigger gear



no visible scorching, melting...etc ...



the board reaks of burnt, the motor not so much... but as above no visible melting, scorching, arcing... nothin...

[He Who Shall Not Be Named]

Yeah. Was that servo fried from the inside or from the outside. That's the big question. And look for any insulation charing on one or more of the three-wires that make up the servo lead.

A thought: You're not using an old AirTronics receiver in there, are you?

David

[Reckless]

Mechanic ... with fabrication and welding on the side ... had a chance to get to the SD right after getting home from work... but a good portion of that is "stained"

I'll see what I can get too tonight... wanna figure out what/how fried before just throwing another one in there.

[He Who Shall Not Be Named]

You filthy animal, you!

Redboat's right -- those are the hands of an Auxillaryman or Torpedoman.

Hygiene issues aside ...

Wow! How can that thing pass enough current to melt the case without first frying those small gauge wires that make up the servo lead?

The heat came from another source. I bet you have your battery cables tucked up tight under the ballast servo when the motor-bulkhead is pushed into place -- is there a plug-connector back there that something could have shorted across, cooking the servo above?

Take that servo case apart and give us a photo-narrative postmortem. The condition of the servo amplifier board will tell the tale.

David

[redboat219]

now that is the hand of a U-boat crew...