From a pilot in Ireland who's Rutan design was scaring him in the rain!

"Before installing the vortex generators Vari-eze  G-BNUI  displayed dreadful pitch down in rain plus oscillations. These were so bad I did not want to fly if it looked wet at all, (fancy having a plane in Ireland that did not like the wet!).

The worst day was not the wettest day but the day that was wet, then dry, then wet, every few minutes. This was deadly. It even felt like it may become so divergent that it may end up diving into the ground or stalling, Something had to be done.

I fitted the generators accurately to your drawing requirements first by making a cardboard chord wise template to mark a datum exactly 50% chord as per drawing. This revealed slight variation in the chord of the canard/elevator r + l so I split the difference to achieve exactly 50% Chord on each side r + l , a length of hobby shop balsa was used as a Template prior to bonding with RTV silicon and that was it, done.

There followed a period of dry weather naturally enough, but a few weeks later I filed a flight plan from Belfast Aldergrove to Isle in Scotland. Ten miles out I hit the same weather as before: wet, dry, etc. and was considering turning back but as I waited for the pitch change as the droplets of water appeared on the canard, there was almost no change Inspiring great confidence in the poor conditions. The oscillations were completely gone and instead of full up trim it only required 3/4 " at most. Since then flying in light rain is not noticeable were before it was terrifying it definitely works !! The cruise airspeed has not changed approx. 120 knots."
 
 

From the owner of a Lake amphibian:

"I have improved my take off on water by 5 seconds and 3 seconds on land. Control responses are superior and I can take-off and land without flaps. Installation on the engine pylon and nacelle improves propellor effectiveness about 6% with speed (increase) of 8 miles per hour"
 
 

From the owner of a Long Ez

"With the VG's installed, I am now ably to safely fly final approach 5 knots slower without risk of loosing elevator authority. Landing distance has been reduced significantly and the loss of trim the plane used to demonstrate in wet conditions has been completely eliminated. Sure is better than having to build a new canard."
 
 

From the owner of two de-certified Cessna's  flown in the Experimental Category
( a 182 with the Robinson STOL kit and a 172 )

The set of VG's you sent me have produced amazing results in low speed control. Enclosed is a check for four more sets (Same application) Thank you
 
 

From a RANS enthusiast

I'm happy to see that you finally have a web page. I've been using your VG's on my RANS S-7 since May 1996. Your VG's had such a phenomenal effect on performance and safety on my aircraft that when I removed the VG for permanent installation and flew the aircraft without the VG's one last time my first thought was..."My God what a death trap without the VG's!!!"

Your VG's lowered my stall speed from 32 mph to 26 mph. I can now three point my conventional geared S-7 whereas before the wing would stall long before I could get the tail down. But possibly the best improvement is in how solid the wing feels at slow speed. Because the boundary layer stays attached the ailerons have a much more solid feel. I mentioned the very low stall speed. In reality the wing never really breaks. It just mushes and I start a controlled decent. You force a stall break with aggressive handling, but it's very mild.
 
 

From another RANS enthusiast

Last year I purchased a set of VG's from your company for my Experimental RANS S-7 aircraft.  Let me tell you that the performance was no less than remarkable. The virtues of your product are extolled throughout the S7 group.
 

Thanks for your consideration
  Jerome "Skip" Lawson - Oregon

About a Titan Tornado

I helped a friend of mine install some of your VG's on an engine cowling he made for his Titan Tornado (a pusher). The engine cover is his own design and he was getting some tail buffeting and rudder floating. On my suggestion he installed your VG's on the sides of the engine covering and PRESTO! his tail problems went away.  You have another fan.
 
 

From the owner of a Q-2 referred to CCI by other VG users

I appreciate very much the work that you are doing, and am very much relieved that you are still providing these fine items! Please continue to assure that aviation community of this kind of product and service!
 
 

From the owner of a Cozy

They work great and I don't have any detectable pitch change in moisture.  I do notice in high humidity that little droplets of water form aft of some of the vg's.  I guess it's like condensation.  Well anyway, the vg's sure beat building a whole new canard!  Thanks,

 Tim Freeze,  Cozy III,   N215TW

From the owner of a Genesis-2 high performance sailplane

Dear sirs,

I found that the wing root fillet of my Genesis-2 high performance sailplane suffered from separation at speeds a little above stall. This reduced the climbing performance in thermals, where low speeds are needed to make small circles.

Experiments showed reduced separation, when VG’s were placed within the fillet just behind the transition point from laminar to turbulent flow.  Tuft testing of the area in question showed separation beyond 0.7C in the fillet.  At speeds a little above separation, the tufts indicated that the airflow turned inward toward the fuselage, and then would wander laterally just before separation initiated.  Placing VG’s in-line with the airflow at speeds near or above the best L/D speeds made their drag negligible, yet at the low speeds the VG’s were expected to energies the air as it begins to flow inward.

Further tests with a drag probe attached to the trailing edge in back of the fillet showed interesting results.  Not only did the VG’s reduce the drag at low speeds, but drag at high speeds was  also reduced, indicating that the in-line VG’s were thinning the boundary layer.

Based on these experiments, the fillet was made bigger (deeper) to see if separation could be reduced without the need of VG’s.  So far, VG’s are still needed to enhance the low speed performance.  More testing is planned using VG’s inclined at the angle you recommend for the Vari-Ez.
 

Bob Salvo

 

More on VG's on RANS-S7

I really don't know at what airspeed the plane stalls during a departure stall ... the airspeed indicator indicates "0" miles per hour due to the rediculously high pitch attitude.  I believe it to be somewhere around 28 mph.  At takeoff power I can hold the stick completely aft and keep the wings level with rudder and it never does stall ... doesn't hold
altitude but never breaks.  Finals are flown at 45 mph which provides very short landings but more importantly, if all goes wrong somehow, the speed and energy involved are very survivable.  Your product provides me and my
passengers with greater safety ... that's a good thing ... glad you're around!

Thanks again for the support!