underboost
underboost verb: to create too little pressure in an engine's combustion chamber.
Verb
underboost (third-person singular simple present underboosts, present participle underboosting, simple past and past participle underboosted)
- To create too little pressure in an engine's combustion chamber.
- It enables you to properly time the automatic loading of the entire system so that the regulator will not overboost, which would cause a hunting action, or so that it will not underboost and cause a deficiency in the pressure.1941, Bulletin - Issues 19-22, page 155
- A pilot wishing to lose altitude rapidly and still not underboost could go to lower rpm, for example, 16 inches mp with 1600 rpm, rather than 16 inches mp with 2,000 rpm.1960, The Engineer's Digest, page 10
Noun
underboost (countable and uncountable, plural underboosts)
- The process of underboosting.
- After much analysis and compromise of the variables such as RPM, altitude, carburetor air temperature, fuel/air ratio, that affect BMEP, a simple solution has been arrived at to prevent underboost.1970, Aerospace Safety - Volume 26
- This procedure requires a vacuum pump and a special compound gauge. (See Table 3-6.) Turbocharger problems lead to poor acceleration in the case of underboost, or poor fuel economy in the case of overboost.1980, Scope and Impact of New Automotive Technology on the Inspection, Diagnosis and Repair Process.
- An instance of underboost.
- So pilots, keep the pressure on to stop underboosts and watch the red lines to stop overboosts.1970, Aerospace Safety - Volume 26
- An underboost can occur whenever an excessively high rpm setting is used with a very low MAP setting, such as when you pull the throttle nearly to idle while descending at high airspeed with a fixed-pitch prop or a constant-speed prop set at high rpm.1995, Fly Like a Pro, →ISBN, page 72
Examples of underboost in a sentence
- The only significant problem encountered is that pilots must be particularly cautious about underboosting the engines during the drops.1973, United States. Naval Air Systems Command, United States. Office of the Chief of Naval Operations, Naval Historical Center (U.S.)...
- It can be stated that while the time at high power outputs must be minimized by the correct operating techniques, the time at the underboost condition must be eliminated.1984, Fundamentals of fixed and rotary wing aerodynamics, page 130:
Forms of underboost
| Verb | |
|---|---|
| third-person singular present | underboosts |
| present participle | underboosting |
| past participle | underboosted |
| past | underboosted |
| Noun | |
| plural | underboosts |
Origin of underboost
From under- + boost.
Questions about underboost
- What does underboost mean?
- Underboost means to create too little pressure in an engine's combustion chamber.
- How do you use underboost in a sentence?
- The only significant problem encountered is that pilots must be particularly cautious about underboosting the engines during the drops.
- What part of speech is underboost?
- Underboost can be a verb or a noun.
- What is the past tense of underboost?
- The past tense of underboost is underboosted.
Words near underboost in the dictionary
Source and license
Adapted from Wiktionary: underboost (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.
Last updated:
Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Flame, not lame-underboost.wav.
Cite this entry: “underboost.” Word.ws, https://word.ws/underboost. Based on Wiktionary, CC BY-SA 4.0.