How the tank works.

01Overview

$FUEL is a token launched on the pons launchpad on Robinhood Chain, paired with SPCX, a Robinhood Chain stock token. Every trade of $FUEL pays a 4% creator tax in SPCX, and that tax flows into an onchain contract called the Tank.

The Tank sells everything it holds in a continuous Dutch auction priced in $FUEL. Whoever pays the price ignites the tank: their $FUEL is burned and they receive the whole tank in SPCX. The price then resets and the tank starts filling again.

• Every trade fills the tank.
• The price per SPCX halves every 5 minutes, falling second by second.
• Every ignition burns $FUEL forever and pays out the whole tank.

Holders who want out tend to use the tank instead of selling into the pool, so exits shrink the supply rather than the chart. Nobody sells. Everybody burns.

02The tank

Fees reach the tank in a few hops:

1. Trade on pons
2. →
3. 5% creator tax in SPCX
4. →
5. pons curve / pool
6. →
7. pons fee escrow
8. →
9. Tank

pons keeps the creator tax on the bonding curve (or in the pool hook after graduation) until it is swept into its fee escrow, and the recipient then claims it from there. The Tank does both steps automatically at the start of every ignition, and anyone can call claimFees() at any time to sweep and claim without igniting.

Sweeping and claiming are best effort. If pons refuses a sweep, the ignition still goes through and pays out whatever the tank holds at that moment.

03Ignition

The auction is priced per SPCX. Each epoch starts with a unit price, initUnitPrice ($FUEL per 1 SPCX), which then decays. The price to take the whole tank is the unit price times the tank, with a minimum burn:

// unit price, in $FUEL per SPCX
elapsed = now − startTime
k       = elapsed / halfLife              // whole half-lives passed
u       = initUnitPrice >> k              // halve k times
u       = u − u · (elapsed mod halfLife) / (2 · halfLife)
if k ≥ 128: u = 0

// total $FUEL to take the tank
price   = max(ceil(u · tank / 1e18), floorPrice)

Between two halvings the unit price slides linearly from u to u/2, so it is continuous and drops every second. With a 5-minute half-life:

Minimum burn

Every ignition burns at least floorPrice $FUEL (100,000 at launch), however small the tank is.

Reset

After an ignition, the next epoch starts with the price per SPCX at 2× what was just paid per SPCX (priceMultiplier), and starts falling again. Pausing freezes the price; unpausing or changing parameters restarts the auction from the current price instead of jumping.

Calling ignite

ignite(expectedEpochId, maxFuelIn, minReserveOut, recipient, deadline)

• expectedEpochId pins the auction you are bidding on. If someone ignites first the epoch changes and your transaction reverts with EpochMismatch instead of paying the reset price.
• maxFuelIn is the most $FUEL you accept to burn. The price scales with the tank and fees can land between your quote and inclusion, so the site sends the quote + 5% (capped at your balance). You pay the actual price, never more than this.
• minReserveOut is the least SPCX you accept. The site uses the SPCX the tank already holds.
• recipient receives the SPCX. The site uses your connected address.
• deadline is a unix time after which the call reverts. The site uses now + 5 minutes.

Before igniting, you approve the tank to spend your $FUEL. The site asks for exactly maxFuelIn, not an unlimited allowance.

04The burn

The $FUEL paid in an ignition is sent to 0x000000000000000000000000000000000000dEaD, an address nobody holds a key for. It is gone for good. $FUEL sent to the tank by mistake is burned with the next ignition too.

The contract counts every burn in totalFuelBurned() and every payout in totalReserveOut(). The site shows the burn as a share of the 1,000,000,000 $FUEL supply.

05Launch-phase safety & renounce plan

FuelTank is an upgradeable (UUPS) proxy with an owner during the launch phase, so mistakes can be fixed before they become permanent. Until ownership is renounced, the owner can:

• pause and unpause ignitions;
• change the half-life (30 s to 1 day), the reset multiplier (1.1× to 4×) and the minimum burn (up to 10,000,000 $FUEL);
• set the $FUEL token and restart the auction. The contract only accepts a genuine pons launch paired with SPCX whose creator fees go to the tank;
• withdraw the tank, or rescue tokens sent by mistake;
• redirect future creator fees elsewhere;
• upgrade the contract.

The contract only allows renouncing while the auction is live, unpaused and the tank is still the creator-fee recipient, so it can never be frozen in a broken state. Check it yourself: after renouncing, owner() returns the zero address and renounced() returns true. The Contracts section of the site shows the live status.

06Contracts & parameters

The live values are read from the contract on the tank page. USD figures are estimates: SPCX from the Chainlink feed, $FUEL from DexScreener.

07Risks

• Smart-contract risk. The code is public and verifiable, but bugs are always possible.
• Owner risk during the launch phase. Until ownership is renounced, the owner can pause, withdraw the tank, redirect fees and upgrade the contract.
• pons fee recipient. The launchpad can move a token's creator-fee recipient through a public, 3-day timelocked community-takeover process. If that happens, new fees stop flowing to the tank.
• SPCX is issuer-controlled. It is a Robinhood Chain stock token; its issuer can restrict or change it. Stock tokens are not available to US persons.
• Sequencer clock. The price decay follows block timestamps set by the Robinhood Chain sequencer.
• Competition. Everyone sees the same price. If someone ignites first, your transaction reverts: nothing is burned, but you pay gas.
• Market risk. $FUEL and SPCX can lose value quickly. USD figures on the site are estimates.

Crypto and tokenized assets are high risk; you can lose everything. Nothing here is financial advice.