Topic: Battery in the gas tank

[Geeto67]

I'm a little bothered by the fact that this post prattles on for two pages and nobody has mentioned the fact that you are moving something heavy higher up on the frame.

The idea sounds neat and should make for a really clean look, it doesn't make much sense to me from a practical standpoint. If you want the bike to handle better, the idea would be to get the heaviest items to the lowest point on the frame. The heaviest items being: the muffler, the oil tank, the battery, and the fuel tank. The muffler is easy (see buell for a solution), the fuel tank because of the nature of these carbed engines is kinda locked in place, and there are plenty of chopper style tube oil tanks that you can mount lower in the frame. This leaves the battery. If you are keeping a stock sized battery then you want that as low as possible on the frame. The full sized battery has to weigh close to 20 lbs, moving it higher up on the frame means that it has more leverage in fighting you when you want to roll the bike from right to left or vice versa. If you are dead set on it make sure you get the smallest battery that will handle your needs. Yausa makes some tiny batteries (the vespa lx50s use a really small one and it still throws the electric starter) so start there.

It makes more sense to me to move the contents of the left side cover into the tank space than it does the battery, perhaps attached to the frame and then covered with the empty back of the tank like CrisPDuk mentioned.

If you really wanted to be novel, find a way to get a v-rod or v-may style gas tank to work on a cb750, then you can cut the bottom off your tank (or make a fiberglass copy) and mount all the light stuff in there.

[dusterdude]

the f6f hellcat had 3 in each wing and the f4f corsair had them too,but i dont remember how many

[kghost]

the f6f hellcat had 3 in each wing and the f4f corsair had them too,but i dont remember how many

Yeah in the wings...not in the fuel tanks.

You'd be interested to know that the corsair had a system for venting the outboard wing tanks with CO2 to prevent fire.

[bill440cars]

Later model Phantoms had guns as bill can confirm.

Many new bikes come with batteries under the tanks - ducati's & bmw's come to mind. They wouldnt do it if their lawyers thought they'd be killing customers. A gel battery would be a must. I have never heard of batteries blowing up - except for cell phone batteries. If one did in it's stock location - it'd take your most special bits with it. If the battery exploded in a cafe hump, you'd probably go #2 out of a tube for the rest of your life. Each place you put it has some consequence.

Batteries can and do blow up ...They vent hydrogen gas. Think Hindenburg.

        Thank you kghost, I just now saw what TT said about the F-4s not having airframe mounted guns and while you're pretty much on bikes, you must have never heard of or seen an F-4E. They actually have an airframe mounted gun under the nose. The F4-E looks similar to the RF-4 (R=Reconnaissance) , only the RF had  a camera in that area.

        While I haven't heard of a battery exploding in quite a while, all it takes is a spark to ignite those gases!           
   

                                                        Later on, Bill

[bill440cars]

               Check this out. I wish I could post the actual thing instead of just a link.

              http://www.elite.net/castle-air/f4e.htm           

                                     Later on, Bill                                                           

[TwoTired]

Later model Phantoms had guns as bill can confirm.

        Thank you kghost, I just now saw what TT said about the F-4s not having airframe mounted guns and while you're pretty much on bikes, you must have never heard of or seen an F-4E. They actually have an airframe mounted gun under the nose. The F4-E looks similar to the RF-4 (R=Reconnaissance) , only the RF had  a camera in that area.

Of course you're right about the F4Es.  Were these air force only variants?  I don't believe any of the Navy Phantom IIs had airframe guns.  I saw none prior to leaving the navy in 72, anyway.  I did see some Marine F4s with POD guns on hard points, though.  I think the Navy used their money to switch over to the F-14 (with guns) as soon as they could.

On another note, I can't find ANY historical record of the Brit lightning having any guns mounted in the fuel tanks.  They had cannons mounted in the nose on some variants, and external missles.  But, their range was so limited, that sacrificing fuel capacity for guns seems - strange.  Perhaps they did it experimentaly?  I can find no record of such a configuration made operational on active duty.  Pointers?

Cheers,

[eldar]

Holy crap geeto, what battery do you use that weighs almost 20 pounds? I use a regular 14ma battery and it is easy to pick up with my finger tips with 1 hand. 10 pounds at most.

While I understand the concern about weight being higher, it could be partially offset. I you do not make the tank any larger and just make the compartment, you will lose a certain amount of fuel capacity. Yes I know gas is not as heavy but to make room for a battery, you will drop almost a gallon and so while weight would increase, it will not be that much extra. and while that weight is slightly higher, in the end you still lose the weight of that gas as all you did was MOVE the bat but dropped gas.

[bill440cars]

         Hey TT, I don't know if the Navy had any F4Es or not. The early models of the F4 had that gun (you were talking about) that could be mounted on, what's called, the "Center Line" mount. You could mount the gun, another auxiliary fuel tank or rocket launchers.

                                                       Later on, Bill

[masonryman]

BTW, are there any thread to how to stretch a gas tank.

If  you want to make something with compound curves bigger or smaller and maintain a nice shape it will have to be quartered at very least the small end split and narrowed or the big end widened

[masonryman]

.........and if you are going to start cutting on a gas tank take the gas cap and petcock off wash out well and while cutting or welding on the tank keep air moving through it all the time wit a shop vac or a air hose. Moving air will keep it clear of gas vapor. Gas vapor in a tight space + fire bad

[TwoTired]

.........and if you are going to start cutting on a gas tank take the gas cap and petcock off wash out well and while cutting or welding on the tank keep air moving through it all the time wit a shop vac or a air hose. Moving air will keep it clear of gas vapor. Gas vapor in a tight space + fire bad

I'm not sure that all shop vacs or vacuum cleaners, isolate the sparking commutator brushes from the suction airflow.  In fact, some of them use this airflow to cool the motor/brushes.  Having such a machine sucking on a fuel/air mix is a bit worisome.

Use the shop vacuum discharge instead of suction to air out the tank if you decide on use such an approach.

Cheers,

[masonryman]

.........and if you are going to start cutting on a gas tank take the gas cap and petcock off wash out well and while cutting or welding on the tank keep air moving through it all the time wit a shop vac or a air hose. Moving air will keep it clear of gas vapor. Gas vapor in a tight space + fire bad

I'm not sure that all shop vacs or vacuum cleaners, isolate the sparking commutator brushes from the suction airflow. In fact, some of them use this airflow to cool the motor/brushes. Having such a machine sucking on a fuel/air mix is a bit worisome.

Use the shop vacuum discharge instead of suction to air out the tank if you decide on use such an approach.

Cheers,

I

I worked in a welding shop for awhile this is just what we did and we usally used the exhaust side blowing in the tank inlet, I don't think any thing inside the vac makes as much fire as a grinder or torch it's being welded with

[CrisPDuk]

Later model Phantoms had guns as bill can confirm.

        Thank you kghost, I just now saw what TT said about the F-4s not having airframe mounted guns and while you're pretty much on bikes, you must have never heard of or seen an F-4E. They actually have an airframe mounted gun under the nose. The F4-E looks similar to the RF-4 (R=Reconnaissance) , only the RF had  a camera in that area.

Of course you're right about the F4Es.  Were these air force only variants?  I don't believe any of the Navy Phantom IIs had airframe guns.  I saw none prior to leaving the navy in 72, anyway.  I did see some Marine F4s with POD guns on hard points, though.  I think the Navy used their money to switch over to the F-14 (with guns) as soon as they could.

On another note, I can't find ANY historical record of the Brit lightning having any guns mounted in the fuel tanks.  They had cannons mounted in the nose on some variants, and external missles.  But, their range was so limited, that sacrificing fuel capacity for guns seems - strange.  Perhaps they did it experimentaly?  I can find no record of such a configuration made operational on active duty.  Pointers?

Cheers,

The Lightning F6 was equipped with a full length belly tank  which made it look like it was 8 months pregnant. At the front of the tank, directly under the cockpit were four cannons.

I think it was an attempt to adapt an already aging and outdated airframe into a new ground attack roll (probably inspired by the usual HMG penny-pinching), which given the aircraft's legendary thirst and reputation for low speed manoeuvring 'quirks', was a project doomed to failure

[Geeto67]

Holy crap geeto, what battery do you use that weighs almost 20 pounds? I use a regular 14ma battery and it is easy to pick up with my finger tips with 1 hand. 10 pounds at most.

While I understand the concern about weight being higher, it could be partially offset. I you do not make the tank any larger and just make the compartment, you will lose a certain amount of fuel capacity. Yes I know gas is not as heavy but to make room for a battery, you will drop almost a gallon and so while weight would increase, it will not be that much extra. and while that weight is slightly higher, in the end you still lose the weight of that gas as all you did was MOVE the bat but dropped gas.

you are right, the battery doesn;t weigh 20 lbs, it just feels that way. However a stock lead acid battery is still friggin heavy. Gasoline is 6.5 lbs per gallon (roughly), so losing that space and keeping the battery would be equilavent of losing 6.5 lbs, which isn't so bad except now the bike's range is decreased. Truth be told I would rather keep the weight of the battery than lose the range.

I saw in the horse recently where a guy built a kz1000 chop and put all the electrics in the fuel tank and then moved the fuel tank to behind the engine and used an electric fuel pump off a camaro to run the fuel. The fuel tank he used was a moon aluminum tank and I don't think he lost any capacity. I like this idea the best because it takes a really heavy high mounted weight and moves it lower down on the frame which is always an improvement. I don't think this will be easy with a cb750 since you have an external oil tank but I can see someone making a tank like that to fit a 550 frame.

[eldar]

Anything that moves weight lower is good on these bikes!