Banner Ad 1

Twin Air Bag rcab

R/C Submarine modelers

Twin Air Bag rcab

Postby timgarrod » Thu Aug 08, 2013 3:45 pm

Evening All,

Need a bit or advice. I know your meant to put the Air bag in the middle of the Submarine but it's not a option for me, so gone with two, two blood pressure bags, the one on the back of the sub used to be on front off the WTC and used to lift the sub by its self but the rear used to always stick up unless under power, so I got a larger one for the front and the moved the old one to the rear. my problem is, is it better to layout the bag as in the picture and have the battery in the middle or have the large bag in front of the WTC and then put the battery there the bag is currently,

Thanks in advance

Tim
Image
timgarrod
Registered User
 
Posts: 8
Joined: Tue May 14, 2013 5:56 am

Re: Twin Air Bag rcab

Postby Art Broder » Fri Aug 09, 2013 9:26 am

Or, you could use permanent pieces of foam board, and the large single air bag in the middle. Tape the foam board in temporary position while balancing, before installing it more permanently.
Art
Art Broder
SubCommittee#0060
RCABS- It's easy to control your own bladder!
User avatar
Art Broder
SubCommittee Member
 
Posts: 487
Joined: Sat Feb 22, 2003 4:35 am
Location: MA

Re: Twin Air Bag rcab

Postby timgarrod » Fri Aug 09, 2013 9:41 am

Thanks but that's not a option for me(would be alot simpler). the WTC box in the middle has been fiberglass on to the hull.

Cheers
timgarrod
Registered User
 
Posts: 8
Joined: Tue May 14, 2013 5:56 am

Re: Twin Air Bag rcab

Postby JWLaRue » Fri Aug 09, 2013 11:21 am

Ideally, it works best to place the battery at the center (of gravity) and the ballast (bag) centered above the c.g.

In your instance, can you put the battery in the middle with the bag above it?

-Jeff
Rohr 1.....Los!
User avatar
JWLaRue
SubCommittee Member
 
Posts: 3865
Joined: Wed Aug 31, 1994 6:00 pm
Location: Annapolis, MD

Re: Twin Air Bag rcab

Postby timgarrod » Fri Aug 09, 2013 11:42 am

Hi, Thank.forgot to say the WTC is a old Darnell box and when the sub lid is on there not very much space between them. I though of put the battery in the WTC but there no room so has to go in the water.
timgarrod
Registered User
 
Posts: 8
Joined: Tue May 14, 2013 5:56 am

Re: Twin Air Bag rcab

Postby Crazy Ivan » Fri Aug 09, 2013 12:10 pm

Given your limited options, it would probably best to keep the battery where it is to avoid shifting the c.g. more forward. Keeping it back more will reduce the effect called "weathercocking" that would make the boat more difficult to turn.

The problem you may have with the two bladders is that there is no way to guarantee that they will inflate and deflate at equal rates. This can cause the boat to pitch radically up or down during the transition period when diving and surfacing. You might to be able to control this somewhat by restricting the air flow to one or both bladders. You might try using small aquarium valves in line with the bladder hoses to fine tune them. Keeping the boat level when hovering will still be an iffy proposition, however.
George "Crazy Ivan" Protchenko
Image

“There are the assassins, the dealers in death; I am the Avenger!”-Nemo
"I'm disinclined to acquiesce to your request; means No!"-Capt.Barbossa
User avatar
Crazy Ivan
SubCommittee Member
 
Posts: 623
Joined: Sun Feb 23, 2003 2:42 am
Location: Rochester, NY, USA

Re: Twin Air Bag rcab

Postby timgarrod » Fri Aug 09, 2013 12:20 pm

Thank Ivan,

I give that a go for sunday. If not I just have to rip out the box and split it into two and hope is doesn't damage the box or the hull.
timgarrod
Registered User
 
Posts: 8
Joined: Tue May 14, 2013 5:56 am

Re: Twin Air Bag rcab

Postby Art Broder » Fri Aug 09, 2013 2:30 pm

From the picture, it looks to me like you could just place the large air bag on top of the box, in the middle and still have enough room for it to inflate into the upper half of the hull.
Art
Art Broder
SubCommittee#0060
RCABS- It's easy to control your own bladder!
User avatar
Art Broder
SubCommittee Member
 
Posts: 487
Joined: Sat Feb 22, 2003 4:35 am
Location: MA

Re: Twin Air Bag rcab

Postby timgarrod » Fri Aug 09, 2013 3:34 pm

Hi, afford not, I tried it and the lid bowed :(
timgarrod
Registered User
 
Posts: 8
Joined: Tue May 14, 2013 5:56 am


Return to R/C Modeler

Who is online

Users browsing this forum: No registered users