Installation of Bendix KLR10 AoA lift reserve indicator (made by Alpha Systems)

[BrianW]

Hi All,

During my last annual I had the Bendix KLR10 installed in my M20J.

Lots of decisions regarding locating the probe to a good location and the indicator to a good location.

They left the in-flight calibration to me, but the KLR10 is giving me the "invalid set point" error when I try to set the OAA (Optimum Alpha Angle).

I had the probe mounted in an inspection panel location.  It is 12 inched back of the leading edge. And the chord indicator on the probe appears parallel to the chord of the wing (see photos).

I contacted Bendix customer support but they seemed like they had no knowledge with the Installation/calibration.

Has anyone here on Mooneyspace installed the KLR10 in their Mooney?

I'd like to find out what angle you installed your probe at? Mine is still set at the default 50 degrees (see photo). 

The Installation Instructions say when I get the "invalid set point" error during OAA calibration to reduce the probe angle in 5 degree increments.  And to cut the opening for the probe larger.

I don't want to make a mistake and do this multiple times.  Once I cut a larger hole thru my inspection panel, for a reduced probe angle, I can't put the material back.

What angle is your probe at?

Any help or photos would be appreciated.

Thanks

BrianW

 

Edited February 13, 2022 by BrianW

[LANCECASPER]

Bending King name on it doesn’t mean much. I would find out who makes it for them and contact that company for support. 

[carusoam]

There are many BK AOAi owners around here…  (use a search to find them)

It was more popular when it first came out….

 

Calibrating AOAi(s) is generally complex enough to want to have two people on board to execute the procedure…

Best regards,

-a-

[BrianW]

Well, I've done 3 flights trying to get a calibration set with no success.  I calculated the 1.3Vs as shown in the Installation Instructions. My landing manifold setting is 13".  I fly the 13" straight and level using the trim and slowed down to 1.3Vs (88 mph in my case). And I kept getting the "invalid set point error".

About a year ago, I incorrectly set the calibration using Vso. But the indications were nonsense.  As such, the KLR10 gave no indication until I was landed and slowing.  As I would turn off to a taxiway the AoA would finally announce "pull up too slow".  Yup, using Vso configuration was wrong for calibration.  But the instructions said to configure it as you would for landing.  I guess they meant say "Fly at 1.3Vs. Set the throttle and prop as you would for landing, and trim back to attain 1.3Vs in straight and level flight".  

Since I was able to calibrate to Vso in the past, if I was able to get it to at least set calibration (albeit at the Vso), then I'd know the KLR10 was still able to calibrate.  This would lead me to believe the KLR10 was working, but I'd have to change the probe angle.  If it couldn't calibrate, then I'd suspect something else was wrong to prevent calibration.

BTW, changing the probe angle requires cutting the metal on the wing surface that the probe passes thru.  And I didn't want to do cutting until I was absolutely sure.

Since I couldn't calibrate in the clean configuration at 1.3Vs, I tried to calibrate in the dirty configuration at 1.3Vso (flaps down, cowl flaps open, and landing gear extended). The KLR10 couldn't calibrate at 1.3Vso either (despite being able to calibrate to 1.3Vso one time in the past).

So my Bendix KLR10 is either no longer working or I need to redo the still air calibration in the hanger.

This is a royal pain. The Bendix Instructions are not 100% clear, Bendix tech support seems unfamiliar with installation or troubleshooting their product, and no-one on any forums seems to have posted any useful pictures or write-up of their installation.

It feels that I am trying to deduce troubleshooting and figure out the installation by myself.  I'd expect this lack of information and trouble for a new or prototype product.  But the Bendix KLR10 has been out for years, and hundreds of these have been installed.

Edited January 17, 2022 by BrianW

[carusoam]

The cool thing about MS…

Find the people that have one and ask them…

There is sooo much written around here daily…. The chance of getting an answer about an older technology that is out of the main stream gets smaller by the day…

people like to help…

You may need to find them and ask…

Best regards,

-a-

 

[LANCECASPER]

This is the only other time that the KLR10 has ever been mentioned on Mooneyspace . .  not much help

 

[carusoam]

The search function isn’t a human being….

It may take thinking up various spellings

https://mooneyspace.com/search/?&q=Klr-10&quick=1&search_and_or=or&sortby=relevancy

[BrianW]

Hi Mark

I've attempted calibration about 4 times unsuccessfully and then 2 more times where I was able to get the OAA to accept.

The OAA is the tricky part of the calibration.  The still-air in hanger calibration and the cruise calibration don't pose the problem.

In order to set the OAA I calculated my v speeds with the based on the planes flight weight vs the gross weight. So instead of Vs being 72mph, I calculated my Vs to be 67mph.  Then 1.3Vs=87mph. But when I tried set OAA calibration at 87mph I kept getting "invalid set point". So I slowed more and tried again and again.  It wasn't until I was at 80mph that the unit announced calibration set. I completed the cruise calibration and landed.

I didn't like that calibration and researched some more and checked my calculations.

I went thru the calibration again yesterday and again I had the be at 80mph or less for the unit to accept OAA.  That is only 1.15Vs!

With it calibrated upon final it displayed cruise.  And as I was rolling down the runway it finally announced "watch AOA", then "too slow".  That's no use!

I will call Alpha Systems for some tech support. I think they make the KLR10 for Bendix.  Unfortunately in my calls to Bendix tech support, they seem to have no technical expertise and are unfamiliar with their KLR10.

[BrianW]

Hi Mark

I've attempted calibration about 4 times unsuccessfully and then 2 more times where I was able to get the OAA to accept.

The OAA is the tricky part of the calibration.  The still-air in hanger calibration and the cruise calibration don't pose the problem.

In order to set the OAA I calculated my v speeds based on the plane's flight weight rather than the gross weight Vs in the POH. So instead of Vs being 72mph, I calculated my Vs to be 67mph.  Then 1.3Vs=87mph. But when I tried set OAA calibration at 87mph I kept getting "invalid set point". So I slowed more and tried again and again.  It wasn't until I was at 80mph that the unit announced calibration set. I completed the cruise calibration and landed.

I didn't like that calibration and researched some more and checked my calculations.

I went thru the calibration again yesterday, and again I had to be at 80mph or less for the unit to accept OAA.  That is only 1.15Vs!

With the calibration complete, when I approached on final, it displayed cruise.  And as I was rolling down the runway it finally announced "watch AOA", then "too slow".  That's no use!

I will call Alpha Systems for some tech support. I think they make the KLR10 for Bendix.  Unfortunately in my calls to Bendix tech support, they seem to have no technical expertise and are unfamiliar with their KLR10.

Edited February 7, 2022 by BrianW

[BrianW]

After talking with Bendix Technical support, I was told Bendix stopped selling the KLR10 in 2013/2014.  Bendix had limited technical information but said the KLR10 was actually produced by Alpha Systems for Bendix.  They gave me Alpha System's phone number.

I went over to Alpha System's website.  Our KLR10 is equivalent to their "Eagle" kit.  They had much better documentation for installation and calibration.  I spoke with (I think it was Mark) at Alpha Systems.  He explained the operation and calibration procedure.

He said the probe angle moves at 5 degree increments.   He called this the "coarse adjustment".  The calibration button sets the "fine adjustment". He said that based on the OAA showing the blue circle and yellow bar below (when it said "invalid set point") meant the probe was angled down too much, and that the probe tip needed to be rotated up 5 degrees to the next locking point, and reattempt the calibration again.

I'm glad I spoke to Alpha Systems for clarification.  In order to rotate the probe tip up, I had to increase the hole size that the probe goes through on my wing inspection panel at the front.

I had to Dremel out about 1/8" material from the access cover at the front of the probe and rotate the probe up. (see photos).

I flew the plane and it calibrated easily at the 1.3 Vs for OAA calibration.

By the way, the choice for the probe location was in the right wing access panel.  There was nothing behind this access cover that requires the removal of this access cover for the regular annual inspection.

The only thing I would have changed would be to cut the probe hole NOT in the center of the cover plate.  I would move the probe 1" left or right of center.  At center, the front center screw gets blocked by the probe (see my photo) and will not allow the use of the center screw. 

Also, I'd shift the inside probe mounting flange as rearward as possible so when you remove that little bit of material in front of the probe (to allow the probe to be rotate up a bit more) the probe hole would not be so close to the front of the access cover hole (you can see its close in the photo).

I'd prefer the front/back placement of the probe hole to look more centered in the cover plate.

This AoA works great now.  I'm happy with my AoA now.  But Bendix no longer sells and supports the KLR10.

Alpha Systems have continued to get better and have great upgrades, accessories, and support.  If you want an AoA, I'd definitely choose an Alpha Systems unit. 

Edited October 29, 2022 by BrianW

[carusoam]

Great Alpha Systems pirep and updated sensor installation for BK’s KLR10 details Brian!

Thanks for sharing all of the detail!

Best regards,

-a-