Vortex generators

[WaiexN143NM]

Hi robbie, all,
i started a thread about vortex generators a couple yrs ago. type vortex generators in the search box above. john, chris, noel, charlie, all had good responses. i had seen a pic and ad from a man in germany who had high claims.
One post talk of a man in red bluff, who, after much testing didnt see any gains.
The flyout to indiana sounded fun. jeffs plane the tri gear w the vortex generators, is it painted or vynl wrap ? and looks like a 3 blade prop, what engine is installed?

Let us know about the vortex generator testing and results.

safe flying

WaiexN143NM
Michael
p.s. u can go to page 1 of this thread to see earlier posts.

[Sonex1517]

I believe the engine was a Rotax. The kit I ordered is around $60 so since it’s something I have been interested in, it’s worth it to me. I am not in any way invested in the design or the sales, and am just exploring the experimental part of owning an aircraft I built.

I’ve yet to see a single tangible report from anyone who actually flew or flies it. My goal is simply to report back on my opinion.

[tx_swordguy]

I put VGs on an avid flyer I had (predecessor to the kitfox line) The wing would dip and wobble up and down as I was coming in to land and made me feel uncomfortable. The VGs fixed that and made the wing rock solid up until it stalled (did drop my stall by 4 mph). The stall then came all at once and the nose dropped. I did not see any benefit or detriment on the upper end of the incredibly fast (80 mph cruise). I have never had any issues with the sonex wing dropping, in fact it wants to float for me. I also considered the VGs because of my good result with the avid. I do not believe they will benefit my particular sonex and therefore never put any on. They may?? help under the horizontal stab or along the rudder IF you feel you need more authority out of either, but I don't think the wing itself will benefit. On a side note the B-52 bomber has VGs on the rudder and horizontal stab.
Mark

[Jlogan1]

I just installed the stolspeed vortex generator kit. Install time was about 1.5hrs to do both wings. I have only had time to do a short flight but I noticed a more stable initial climb out and landing approach and also a solid 4 mph slower stall speed. Still need to see if they had any affect on cruise speed. It took 72 Vgs to do the wing. I plan on adding them to the horizontal stabilizer in hopes of getting a little more elevator control in the stall. The kit cost was $99 and was purchased through aircraft spruce. Looking forward to doing more flight testing once weather improves.

[Sonex1517]

Great feedback! What measurement did you come up with for mounting them on the wing?

[Bryan Cotton]

How are they to polish, I wonder.

[Jlogan1]

Hi Robbie, I just followed the instructions included with the kit which was to put the vgs highest point at 10% of the wing cord and that point the front edge of the vg at about 7%. It worked out the front was in line with the front edge of the 3rd row rivets on the wing!

[Jlogan1]

Bryan, the vgs are polycarbonate and held on with 3m double sided tape. They are on there secure for flight but can be knocked off. I will have to be very careful when i polish around them!

[Sonex1517]

While it may be safer for me to discuss this November’s election, the current events in America, religious preferences, and sex all once, I will post some facts about my VG testing. I am not trying to change anyone’s mind. I am reporting what I learned in my airplane.

I installed the kit from Aircraft Spruce this past winter. I have done some fairly extensive testing, and this past weekend during my WINGS training, my CFI and I wrung out the Sonex thoroughly.

First thing is that prior to this, my Sonex would actually stall. It made loud oil can sounds just as it did, then the nose dropped. This no longer occurs in the same airplane, no other mods that could change it. The airplane will not stall. It wallows, it wiggles, it washes around. No break at all.

I release the slightest amount of back pressure and it’s flying again. Most interesting to me was no oil can sound at all. It used to be very pronounced.

Second thing is in a turning stall, it no longer threatens me with bad behavior. I will be the first to admit I had not been aggressive with this test in the past. Sunday we did turning stalls with the stick in my lap. No bad behavior.

In both of these tests my airspeed indicator was pegged at the bottom and my LRI danced far down in the red.

Third thing was Minimum Controllable Airspeed (MCA). This blew me away. I can turn the airplane at MCA like never before. We practiced an engine out procedure and lost less than 300’ - more like 250’. This does not change my personal decision of no turning back below 800’ AGL but it was eye opening. I was able to make an aggressive left 45° bank, rudder almost to the floor, at 70 mph with the stick back.

In my opinion, the LRI truly pays off at MCA. I can play around and know when I have lift remaining.

Finally, landings. I am able to land my Sonex more consistently, more smoothly, and - most important for me at 1C5 with a nearly constant crosswind - maintain better control with the VG’s, especially for whatever reason with a crosswind from the right. I was finally able to successfully wheel land the airplane, something that eluded me previously. I’ll blame my poor piloting skills for that.

Last weekend I was able to keep it on one wheel longer than I ever was able to in a strong crosswind.

I installed the VG’s on the wings, the horizontal stabilizer and the vertical stabilizer per the kit plans.

Clearly this is a somewhat touchy subject. But in the interests of factual data, I wanted to report my own experience. Your experience and opinion may vary greatly.

[Rynoth]

<insert witty comment here>

Robbie, thanks for the report. Your empirical evidence is very intriguing to me. Were the generators installed on the top or the bottom of the horizontal stabs (I'm assuming the bottom)? I'm curious how they would be installed on a Waiex at the tail.