Welcome to our Terms and Definitions Feedback Form!

Just as with every other publisher of rapidly evolving, complex content, occasionally there are things that we can improve upon. Sometimes the reasons for this are technical and sometimes they're not. What makes our materials and system unique is that, thanks to this direct link to our editorial team which you are now using, we can rapidly consider and incorporate your feedback. We hope that you can appreciate that we have this system in place not because our stuff is shoddy, but, rather, because it is good.

We gladly and sincerely welcome constructive, considered, and, where possible, cross-referenced feedback on specific items of content using the form below.

  • This is not the place for technical or customer support requests! We'll be happy to hear from you on such issues via our Online Helpdesk. Please use this form only to provide feedback relating specifically to one very particular piece of content (such as a single term/definition) as your message here will go to our editorial team only, not our technical or customer support staff. You will not receive a timely response (and in fact might get none at all) if you submit such a message through this system instead of via our helpdesk.
  • Please make sure your app/program content is up to date before using this feature - A very high percentage of false reports we get via this system can be traced to the fact that the user does not have the latest version of the program content on his/her device. Please be 100% sure (especially if you are thinking about submitting a ticket about a "missing image") that before submitting a ticket here that you have used the in-app or in-program update utility for the program or app in question (often available via a 'get updates' or 'check for updates' link or button from the main menu). This will also help ensure that you are studying the latest and greatest material!

Here is the current term:  If below it different substantially compared to how it appears in your app/software, be sure to update your software/app's content prior to using this form.
Lift Reserve Indicator
The Lift Reserve Indicator (LRI) has been proposed as an alternative or backup to the Airspeed Indicator (ASI) during critical stages of flight. This is an elegant device but is rarely found in light aircraft or even transport jets. The conventional Airspeed Indicator is less sensitive and less accurate as airspeed diminishes, thus providing less reliable information to the pilot as the aircraft slows towards the stall. The actual stall speed of an aircraft also varies with flight conditions, particularly changes in gross weight and wing loading during maneuvers. The ASI does not show the pilot directly how the stall is being approached during these maneuvers, whereas the LRI does.

The LRI shows the pilot directly the Potential of Wing Lift (POWL) above the stall at all times and at any airspeed, so it is more descriptive and easier for the pilot to use. The LRI uses dynamic differential pressure and Angle of Attack to operate. It is very fast acting and extremely accurate at low airspeeds, thus providing more reliable information to the pilot as airspeed diminishes and becomes critical.

The LRI uses a three zone, red-white-green display. During flight, the green zone is well above the stall where flight controls are firm, angle of attack is low, and the unused POWL is high. The white zone is near the stall where flight controls soften, angle of attack is high, and the unused POWL is diminished. The top of the red zone defines the beginning of the stall. The severity of stall increases as the needle travels deeper into the red. During the takeoff, the LRI uses dynamic pressure to operate and will not lift the needle above the red zone until enough airspeed energy is available to fly.

The pilot adjusts the instrument to indicate the edge of the red-white zone during minimum airspeed practice at altitude, indicating the aircraft has zero POWL beyond that point. Since the wing will stall at the same angle of attack at any airspeed, once properly adjusted the LRI will indicate the red-white edge anytime the stall is approached. This includes landing stalls, climbing stalls, and accelerated stalls. After adjustment, the black line in the center of the white indicates maximum angle of climb and maximum angle of descent with enough reserve lift for the landing flare. With practice, the pilot can use the LRI to determine the exact moment for liftoff with minimum ground roll and maximum angle of climb combined.

The LRI has been well received by STOL pilots and pilots of experimental or home-built aircraft. The LRI is very useful for short field landings, short field takeoffs, and slow speed maneuvers such as steep turns, steep climbs, and steep descents, and also allows pilots of fast or "slippery" aircraft to land with little or no float very reliably. Since the LRI is so useful at the critical lower end of the flight envelope, most pilots will use the LRI as a complement to the ASI, using the LRI for slow speed work and the ASI for cruising and navigational work.

source: Wikitionary / Wikipedia and Related Sources (Edited)
Please do not use this form to tell us that the definition you saw doesn't necessarily match the context where you saw it. We use an automated keyword-based system to match the tens of thousands of definitions in our glossaries with our material. Sometimes, when a term has more than one meaning or use or when an abbreviation might stand for more than one thing or resemble a 'normal' word, this results in a definition for a term being shown that doesn't necessarily match the context. Please do not report such issues here. Rather, please use your best judgment to evaluate whether such definitions apply to what you're reading. If the answer is 'no' but nevertheless you feel the term doen't have a good definition in our system but should, please go back and find the 'suggest a term' link in the app. Thanks!
We welcome your feedback.  Please carefully fill out the specifics below. If you wish to comment on more than one term/definition, please fill out and submit this form separately for each.
Please Identify Yourself.  It's important, so that we can get back to you with feedback or requests for clarification.
Please enter your email address above solely for the purpose that our editorial team might, if necessary, contact you with questions, comments, or requests for clarification.


© Dauntless Software all rights reserved.