Flightline OV-10 Bronco VG test

[jetpltrich]

Real plane stuff usually doesn't translate well to models, however, for me modelling is for imagination and experimentation. With that I wanted to see how Vortex Generators VG's would translate to model airplanes. My experience on my personal experimental plane has changed the flight characteristics from a handful to delightful. Lowering stall speed, more effective control response at low speed, shortening takeoff and landing respectfully, and of course a slower cruise. The saying goes Lift is Drag and VG's provide lift and the also create drag. So, with that I decided to take my Flightline OV-10 and install some VG's on the wing and see what happens.

OV-10 VG test complete! Speeds obtained done with Spektrum onboard GPS. Weather: 10miles, 12000ovc, winds light 2-4 out of the east. Takeoff runway 36 and was slightly shorter than normal by about 3-5 feet. Initial response was a climb like I haven’t seen plane do before. Gear up flaps up and did normal cruise power of 70% throttle. 45mph into the wind 50mph with the wind, a loss of speed it appears. Pushed it up to full power and 55mph into the wind 60mph with the wind. Normal speed without VG’s full power is 70mph plus average. Stalls: I did three stalls and the plane got pretty slow. Stalls were done into the wind power off and each stall presented a 15-18mph GPS Groundspeed. I did a few stalls the other without VG's and they averaged 18-20mph. The stalls also did as GliderGuy and I predicted, mushed and no fall off on either wing unlike the other day. Adding 20-25% throttle immediately arrested the stall to recovery. Landing was crosswind and a little shorter than normal with a much higher alpha presentation on Flare. All said they did as I predicted though I need more up elevator authority. Will I keep them on? Up for debate though I will do a few more flights with them on to obtain more data.

An interesting experiment that I wanted to share.
Richard

[Evan D]

Interesting, thanks.

[NewbieBob]

Keep us posted Richard it is a very interesting matter especially with the OV10.
thanks
Bob

[jetpltrich]

Today I redid the VG’s on both wings essentially removing half of them. This was done to regain the cruise speed I had lost yet still have some good low speed flight characteristics. By all means do not miss understand what I’m doing here, the OV-10 out of the box is an awesome low speed flyer, my objective here is to experiment and have fun and to see if VG’s have an effect on these planes.

The VG’s left were directed to one angle offset and trimmed to have a slight aerodynamic shape. If you look closely you can see that. The square ones did the trick, however, I think this aerodynamic profile is better.

I flew the airplane twice and she retained the short field liftoff and climb. Cruise speeds were slightly less than the normal wing by just a few mph’s. Two stalls showed an 18mph stall with the mush maneuver exhibited in yesterday’s flight test. What I really took notice of is how stable approach to landing is and how ground effect floats the plane and the ever increasing flare. I made numerous landings and how pleasant they are just astounded me. I am now considering VG’s on the outer portion of my T-45 to eliminate the wingtip stall that I get on landing every once in a while. With this shape and distance between the VG’s I think it will eliminate that.

Please feel free to comment.
Richard

[SanExup]

Do you think flaperons or spoilerons would help with the T45s wingtip stall?

[GliderGuy]

Do you think flaperons or spoilerons would help with the T45s wingtip stall?

A simple solution to the tip stall of the PJ-50 is to adjust each aileron so it is 5 mm up when the stick is neutral.

That’s 5 mm up from being streamlined with the normal trailing edge.

Betting this works for the T-45.

Having up aileron on both sides reduces the effective angle of attack at the tips. Basically, adjusting in tip wash out.

-GG

[SanExup]

Thanks GG!