Lift Reserve Indicator

[dcstrng]

Addendum: when I got home last night my LRI was there – Kelly shipped much quicker than I thought and nice work… I agree, it probably could be made by a careful hobbyist, but this would only slow me down (for which I don’t need any more excuses) and is one more thing off my list…

[fastj22]

They are quite simple. An industrial pressure differential gauge with a custom face plate and adjustable probe. The probe would be the most difficult to fabricate in your shop.

[Rynoth]

Yesterday I took delivery of my LRI kit from Kelly, his website is https://sites.google.com/site/lrikit/

I got the plastic probe. I discussed with him how it's made, and he actually makes it using a 3D printer. I researched the material and finishing process he uses and was satisfied that it would be a durable product. The probe itself weighs 45 grams (heavier than I expected, it feels robust) and feels more like ceramic than plastic.

I will give Kelly an 11 out of 10 in customer service. Besides our informative email exchanges prior to my purchase, I accidentally sent him 2 separate checks (via online bill pay) for $225. He caught the error before I did, informed me, and at my request he voided the second check and sent me a picture of the voided check, and shredded it. Thanks Kelly!

[fastj22]

That's a perfect application of a 3d printer. I'm sure it will be plenty robust for your needs.

[Darick]

Thanks guys for all the input. I went with the plastic probe.

When I received mine, the first question was the material, as it had an unfamiliar texture and weight density. The 3D manufacturing explains this.

[jmattson]

Morning everyone, could someone explain the pros to having a LRI? What does it do that an airspeed indicator won't? Is there maybe a website to look at that will explain everything? Maybe a past post that I missed? Forgive me, I'm new to this particular instrument... Thanks guys!

[Rynoth]

Morning everyone, could someone explain the pros to having a LRI? What does it do that an airspeed indicator won't? Is there maybe a website to look at that will explain everything? Maybe a past post that I missed? Forgive me, I'm new to this particular instrument... Thanks guys!

It's a little hard to explain if you've never seen an AOA gauge in action. One way to think of it is as a visual representation of your typical stall warning horn (which the Sonex does not have either.) It will give you an instantaneous visual readout of your proximity to stalling. Since weight changes the stall speed of any aircraft, the LRI (once properly calibrated) should actually be more accurate for finding a proper approach/landing speed than the airspeed indicator alone. Granted, if you always fly at the same weight, this becomes less of a factor. Still, the LRI provides additional information that can help you understand the low-speed envelope of your aircraft better, in real-time.

Another pro would be its use as a backup to the airspeed indicator should anything happen to the pitot/static system. The lri uses its own probe and lines.

This website has a FAQ with some more info. http://www.liftreserve.com/

Here is how I installed my probe: http://www.rynoth.com/wordpress/waiex/2 ... indicator/

[Rynoth]

Thanks guys for all the input. I went with the plastic probe.

When I received mine, the first question was the material, as it had an unfamiliar texture and weight density. The 3D manufacturing explains this.

The 3d printed probe is paintable, but don't sand it! Kelly told me that the hardening agent that makes the probe durable only penetrates about 0.10"

[Sonex1517]

Summary of LRI here

http://sonexfoundation.com/Lift_Reserve_Indicator.html

Article here

http://sonexfoundation.com/uploads/Culver_Lift_Reserve_Indicator.pdf

Robbie

Sent from my iPad using Tapatalk HD

[jmattson]

Thanks guys for the info! Much appreciated!