LancAir IV Winglets and Tail group Modifications

The Problem

The Lancair IV series of aircraft are very high-performance aircraft that do not meet the standards that certified aircraft must adhere to for FAA SEL aircraft.  They operate with wing loadings and speeds that are closer to that of a small corporate jet aircraft. The stall characteristics are closer to a Lear 35 than SEL GA aircraft, like the C-T210 or Bonanza A36tc.  Because of the high-performance design of Lancair IV’s, the aero surfaces were designed to a minimum to achieve high speed operations.  The wing area of the IV is apx. 100 ft sq, which is only 57% of a Cessna C-T210, in addition they operate at approximately the same maximum gross weights or more! Lancair IV’s features very low wingtip wash out, appx 1.3 Degrees. The airfoils featured on the Lancair’s are Natural Laminar Flow Series (NLF-series).  The airfoils are great at producing lift and low drag, but when stalled, they do so aggressively.  When stalled, the drag rise is sharp and strong.  When Reynold’s number effects are accounted for, the entire wing basically stalls at the same time.  When it stalls, the wing not only drops rapidly but also is pulled aft by the dramatic increase in drag.  The result is usually a stall that ends up in a spin. The spin has flat spin attributes depending on the C/G and is typically unrecoverable with the altitudes that it typically occurs at (below 5000’ agl).

Our Solution

L/D Max, has spent the last 10+ years developing and refining our technologies.  When applied to the Lancair IV series, it greatly reduces the inherent characteristics that have been the cause of so many accidents and deaths.  The winglet is shaped to control the airflow over the entire wing, but its effects are most prevalent at the wing tip.  It energizes and modifies the airflow to allow a higher AoA before the entire wing stalls and especially the wing tip region.   That allows the root of the wing to enter a stalled condition without the stalled air progressing rapidly out towards the wing tip!  The result is greatly improved stall characteristics that are much more inline with FAA SEL certified aircraft. 

The tail-group modifications are to address the lack of vertical (Yaw) aerodynamic authority.  It also has been designed to operate effectively at lower speeds and to greatly improve stall recovery, as well as spin prevention/recovery in case the pilot forces the aircraft into that scenario.

The package consists of winglets, a vertical aero strake/feature with a rudder extension.  These are both required to achieve the desired safety improvements.

The Results

The winglets/tail modification improves the climb rate.  Climb rate typically double in the upper 1/3 of the aircrafts climb/cruise altitudes.  Flying higher increases overall safety by giving the pilot more time in case of emergency to address the issues and getting out of congested airspace.   Cruise speed improvements range from 0 to 23 KTAS but we highly recommend that the pilots reduce the power and take 5%-10%+ fuel savings.  This also improves reliability/safety as the motor will not be taxed with higher horsepower outputs.  The engine out glide improves by 10-20% which adds safety as more suitable landing airfields now come into range. We are hoping to add some increased speed to your aircraft but that is not the aim.  We are improving the stall characteristics along with the prevention and recovery in case of a life threating situation.  The improved climb, fuel savings and possible speed improvements are a bonus. 

How to apply

The pilots are required to complete our Lancair IV Winglet/Tail equipped aircraft high performance training program initially and annually for insurance qualifications. This is the only modification and training program that is endorsed by any insurance underwriter.  Insurance rates as low as 2% of the insured value for FULL coverage are possible.

To qualify for this program there is a three-step process. 

1. Contact our preferred broker:

Alex Hunt

Assured Partners

316-461-7883      

The broker will collect your pilot history credentials and supply them for review to the underwriter.  When approved you move onto step two.

2. Interview by L/D Max. We will have a discussion to evaluate your currency and most importantly your trainability. We will only put these modifications on aircraft whose pilots have a safety mindset and are willing to train to the standards that will ensure safe operation of these incredible capable aircraft.  Our modification greatly improves the ability to increase the safe operation of these aircraft, but it can only help the pilots who strictly respect the limits. 
3. Installation and of the modifications and flight training. Installation takes 80–100 man hours. Flight training is typically 6-10 hours. Included in the package are 4ea 2-hour flight training events.  If more training is required for consistency/proficiency additional training is available at additional cost.

Fuel costs are at the owners expense.  Please see the installation contract for further details.  

An important consideration is that the investment of this modification has a calculatable ROI. Slower landings, increased climb rates, lowered power requirements at cruise for the same speeds or climbs to higher altitudes thus lower fuel burns for increased TAS and improved glide angles all contribute to lower operating costs in fuel and aircraft/engine wear.