Canadian Flag Blowing In The Wind Ron Leclerc Zenith CH701 Construction Log


Zenair CH701 STOL Aircraft...
CH701 STOL

Winnipeg

Home Page...

Project Page...

Factory Page...

Tips & Tricks Page...

Rudder Page...

Horizontal Stabilizer Page...

Elevator Page...

Wings Page...

Flaperons Page...

Front Fuselage Page...

Rear Fuselage Page...

Firewall Page...

Landing Gear Page...

Instrument Panel Page...

Instrument Panel Page...

Controls Page...

Electrical Page...

Fuel System Page...

Engine Page...

Engine Page...

Engine Page...

Engine Page...

Tools Page...

Tools Page...

FAQ Page...

Local Weather Page...

Click for Winnipeg, Manitoba Forecast

Search My Site

Zenith Aircraft Co.

This site has no affiliation with Zenair or The Zenith Aircraft Company...

Sign Guest Book My Guest Book


Disclaimer:
The use of information from this web site is experimental
in nature, for educational purposes and is USED AT YOUR OWN RISK!

Click to join AirVW-Eng-Builders
Click to join
AirVW-Eng-Builders

Click to join flyfloatbuilders
Click to join
FlyFloatBuilders

Visit Zenith Aircraft
Builders and Flyers

Metric Converter

mm
ft
in

Note:
1 in = 25.4 mm
1 ft = 304.8 mm
1 ft = 12 in

 
 
Page 1
Lift Reserve Indicator: 1 |
 

What is a Lift Reserve Indicator(LRI)? Well it could be - AN Angle of Attack Meter(AOA)... or an Air Speed Indicator... or a Lift Management System... OR it could be all of them! It is basically an indicator of lift at when the wing stalls. This is a very simple in-expensive device used to monitor the stall characteristics of the wing! This unit can be purchased commercially... or can be built from parts that are very easy to acquire. The Indicator Gauge... is a Dwyer Minihelic II" Part Number: 2-5002 (0-2" H2O) is acquired from - Surplus Center Or from - Dwyer Instruments and is modified by changing the face plate with the 3 colored regions... Red, White and Green. LRI Gauge Faces The Probe is available online or you can have one made based on the enclosed drawing - LRI Probe. I purchased my probe from John Bolding in Texas!

The LRI or AOA indicator is especially suited for short runway landings and takeoffs... By calibrating the unit to indicate lift you can determine when the wing will stall. The probe is installed on the underside of the wing out of the prop blast and approximately 15% to 30% of the wing chord back from the leading edge at an initial angle of 50 degrees! When the wing stalls this event occurs when the needle leaves the white zone and transitions into the red zone and at which time the wing can no longer produce lift. The key is to calibrate the unit at this point so that when the needle transitions from the white zone near the red zone you know that you have lost lift and are entering a stall. This needle reading is independent of the loading and density altitude and once calibrated and tested, it is a reliable device! So the 3 colored zones are RED - NO lift... White - just enough lift to maintain level flight and... Green - an abundance of lift!

Calibration:
Calibrating the device is a very simple process! The only point that must be established is when the wing no longer produces lift... the transition from the white zone into the red zone! Set the initial probe angle at 50 degrees... then climb to a safe density altitude and produce a stall at cruise power and as the speed slows to stall speed the LRI needle will begin to drop from the green zone(abundant lift) and then transitions into the white(level flight phase) zone. It is at this point attention must be paid in the transition of the needle from the white zone into the red zone where a full stall should take place! There should be no lift(zero) at this junction of the red/white zone... if there is lift then an adjustment of the probe angle must be done. In other words if the needle gets to the red/white zone before the stall then the nose of the aircraft is to high so the probe must be adjusted down(+ 50 degrees) and if the nose of the aircraft is to low then the probe must be adjusted upward(- 50 degrees) before the next flight! Perform the testing and adjustment of the probe angle until you have it where it should be and can reproduce the stall point.

Now once the initial testing and setup phase is done... run the test again at different aircraft weights, flap settings and density altitudes. You will find out the use of the LRI device is independent of the aircraft weight and density altitude... it's just that simple!
For liftoff once the needle transitions out of the red zone into the white zone... there will be adequate wing lift to be safely rotate in a safe flight attitude without a stall occuring! Do your testing...
 
Click for larger view...

June 1, 2007
Lift Reserve Indicator Gauge... is a Dwyer Minihelic II" Part Number: 2-5002 (0-2" H2O) purchased from Surplus Center or from Dwyer Instruments! The Gauge Face does not come with the colored face markings, it must be modified with the required indicator markings.

Click for larger view...

June 1, 2007
Lift Reserve Indicator gauge... with a(PDF File) LRI Gauge Faces to be applied to gauge face...

Click for larger view...

June 1, 2007
Lift Reserve Indicator gauge, with the new face applied...

 
Click for larger view...

June 1, 2007
Lift Reserve Indicator Probe... I purchased the probe from John Bolding(CH701 builder in Texas) for $35US, he was making them. It should be noted that it is not a heated probe...

Click for larger view...

June 1, 2007
Lift Reserve Indicator gauge, probe and some of the tubing needed to install. For more information on the LRI use and installation check out this Builder web site or Lift Reserve Indicator web site...

Click for larger view...

June 1, 2007
LRI Probe drawing Found this drawing on the internet somewhere, click for larger view...

 
 
Click for larger view...

May 19,2012:
Lift Reserve Indicator Probe and mounting plate, made out of 0.032 along with mounting angles...

Click for larger view...

May 19,2012:
Lift Reserve Indicator Gauge mount and Probe wing mounting plate along with assembly parts... require about 25' of 3/16" hose for installation from the wing to the panel!

Click for larger view...

May 19,2012:
Lift Reserve Indicator Gauge and Probe mounted... The Indicator gauge is mounted on the glare shield in full view of the pilot! The Probe is mounted on the underside of the wing out of the prop wash. The adjustment angle is set by calibration with a starting point at 50 degrees down from the underside of the wing. The mount is designed with a Probe range of 45 to 90 degrees!

 
Click for larger view...

May 19,2012:
Lift Reserve Indicator Gauge mount and Probe wing mounting plate along with assembly parts... another view

Click for larger view...

May 19,2012:
LRI Gauge Mount drawing... made out of 0.063 aluminum. Gauge to be mounted on the glareshield directly in front of the driver...!

Click for larger view...

May 19,2012:
LRI Probe showing the minimum 45 degree angle... best to start calibration at 50 degrees...

 
Click for larger view...

May 19,2012:
LRI Probe showing the maximum 90 degree angle... best to start calibration at 50 degrees...

Click for larger view...

May 19,2012:
LRI Probe Typical Install - approximately 15% to 30% of wing chord... back from the leading edge...

 

 
Page 1
Lift Reserve indicator: 1 |
 
Air Mail...


Home ][ Favorite Links ][ Local Weather ][ FAQ ][ E-Mail
Copyright© 2008-2015 Ron Leclerc CH701 Project
WebMaster