Downdraft (BTD6)

"Blows Bloons away from the Heli, back toward the entrance."

- BTD6 description

Downdraft is the third upgrade of Path 2 for the Heli Pilot in Bloons TD 6. Similarly to its Bloons TD 5 counterpart, Downdraft will regularly blow bloons backwards with its rotors. The blowback effect can be compared to the tornadoes from Druid of the Storm or the effects of Ninja Monkey's Distraction upgrade. Lead Bloons and Frozen Bloons cannot be blown back.

The Heli Pilot will periodically produce bursts of wind that are capable of blowing back up to 1 bloon every 0.15s (every 0.12s with 0-3-2), equivalent to around ~6.67 bloons per second (every ~8.33 with 0-3-2). Blowback distance is between 32 and 300 units. Considering its consistent blowback rate, it is best used against strong non-MOAB-class bloons like Ceramic Bloons (especially against Super Ceramics).

It costs $2,550 on Easy, $3,000 on Medium, $3,240 on Hard, and $3,600 on Impoppable.

Summary
Downdraft is the most reliable option for blowback in the game, due to its effective manual control and consistent blowback. While expensive compared to other blowback options, its high controllability makes it an ideal option on any map condition, including the hardest of maps. It sees the most use in late-game runs when used to reduce progress of Super Ceramics from particular areas along the track, particularly in CHIMPS Mode. In addition to simply blowing back progress of Super Ceramics anywhere, Downdraft is a popular and reliable choice for stalling, often paired with 0-1-2 Ice Monkeys for near-infinite stalling.

Tips

 * There is no major advantage of using crosspathing, so using 0-3-0 is generally sufficient for applying consistent blowback against bloons. Crosspathing can be added to assist with necessary applications, whether it be needing automatic targeting via Pursuit or blowing back bloons at a faster rate.
 * Try the Pursuit upgrade for relatively easy blowback against the Ceramics that spawn from MOABs.
 * Alternatively, if manual micromanagement is preferred, use the 0-3-2 Downdraft (with Faster Firing) for a faster blowback rate.
 * Pair this with 0-1-2 Ice Monkeys for good stalling of Super Ceramics.
 * Technically speaking, the Downdraft effect can be improved via Berserker Brew and Stronger Stimulant, which will allow it to blow back a greater number of bloons at a faster rate because of the combined pierce and attack speed buffs. However, the Downdraft effect will consume Alch buffs quite quickly whether or not its other attacks are active or not, which means increasing blowback power by those methods aren't always reliable.
 * Unlike Druid of the Storm, glue and ice are not blown back by Downdraft's blowback.
 * There is an interesting interaction with Frozen Bloons whereby the Downdraft effect can affect them only after the bloons defrost. This was discovered in Version 25.0 after Ninja Kiwi applied a damage types rework for many towers in the game.
 * Downdraft is especially useful at holding back Super Ceramics nearing the exit and providing an option to stall rounds once all blimps are popped.

Trivia

 * In BTD6, this upgrade costs $500 more than in BTD5 for the upgrade alone ($3000 instead of $2500), but overall a 0-3-0 costs $400 more than the respective BTD5 crosspath counterpart due to the Bigger Jets cost decrease and base Heli Pilot cost increase.
 * There was a strange interaction with Downdraft and Monkey Intelligence Bureau whereby MIB allows Downdraft to blowback Leads but not Frozen, even though Downdraft normally blowbacks neither Frozen nor Lead. As of 25.1 testing, this glitch no longer exists. Instead, Downdraft is unable to blowback Lead or Frozen Bloons completely. Frozen Bloons unfrozen are still are blown backwards if affected by at least one Downdraft effect, even after 25.1.