PetitCessnaVoyageur wrote:
Do jets really wear VG from initial conception ?
I don’t think so. The vortex generators usually are added after flight testing reveals aerodynamic shortcomings.
PetitCessnaVoyageur wrote:
I had never noticed that on airliners.
Here are some random images from a quick google search showing VGs on a variety of airliners:
On the Mustang they are rubber blocks embedded in the boots on the leading edge.
The VGs you showed on the nose of the 737 aren’t there for aerodynamic reasons, but because the flight deck is so bloody noisy at high speed that they need them to reduce the airflow impingement and noise for the drivers!
Peter,
I’ve flown two airplanes with MicroAero VGs before and after. Very hard to spin after, so that’s one possible answer to your OP question. I guess flick rolls might be correspondingly difficult to initiate, but never had them fitted to a suitable ship to try that.
The other side of that coin is that Langewiesche’s stall-down approach at 1.0 Vso is rock solid (or 0.6 Vso if hydroplaning). The latter confers an 80% reduction in ground roll, none of which is remotely useful to 99% of pilots. If flying a normal SEP from one proper runway to another, I couldn’t say they’re worth the $700-ish and half day’s work to fit. If Mauleing a load of gear to a hayfield or beach, they’re priceless.
MicroAero allow flight with up to 5 VGs missing. They supply a spares kit, but I’ve never known one come unstuck.
Reading a thread about STOL equipment for Cessna recently, I remembered this post, and wondered if @STOLman had some vortex generators fitted on his extremely STOL-performant aircraft.
Maybe the aerodynamics, with canard, is so good, they didn’t bother ? :-)
Besides, since 2015, did anyone give a try to VG installation on its airplane ?
Just came through this study, which seems to have been conducted seriously, about the impact of VG on a Beech Baron G58
http://www.nar-associates.com/technical-flying/BaronG-58VG/Baron_G-58_Report_web_screen.pdf [ local copy ] – URL fixed
Long story short:
G58 is a more complex airplane of course.. Wonder if it is as bad on SEP.
No VG’s on my Katmai. They certainly work but the approach Todd Peterson took with the Katmai was to use the Canard to take the weight off the nose during slow speed (<60 knots) to both look after the nose wheel on rough terrain and make the slow speed control better (and reduce stall speed). A rate one turn at 45 knots is a Katmai part piece, the turning circle is amazing. Above 60 knots the Canard does nothing. Wing extensions further reduce the stall speed which is 31 knots.
But, all this costs a lot of money. VG are great value and do improve things generally but not in the same league as going the expensive route as I did. Not many aircraft can carry 4 people and bags 1000nm at 140 knots true airspeed burning 11.5gph out of or landing at a rough, wet 400m airstrip with trees at each end.
A newly built King Katmai (which cannot be newer than a 1980 airframe) with the very latest avionics and all extras will set you back today $450,000+. I bought mine for the long term so price was easier to swallow.
STOLman wrote:
Not many aircraft can carry 4 people and bags 1000nm at 140 knots true airspeed burning 11.5gph out of or landing at a rough, wet 400m airstrip with trees at each end.
Is there any other ? 
VGs also reduce the maneuvering speed because they lower stall speed. I don’t know if this is taken into account when flying in turbulence but it should.
If I understand correctly there are two dimensions
)dirkdj wrote:
VGs also reduce the maneuvering speed because they lower stall speed. I don’t know if this is taken into account when flying in turbulence but it should.
