Increase cruise speed on Superstol.

[bizkid]

Hi everyone,

I’m looking to optimize my Just Aircraft SuperSTOL to achieve better cruise speed without upgrading the engine or propeller. I’m aware that installing flap gap seals, elevator, and rudder seals can help reduce drag and improve speed.

Are there any other modifications or tweaks on the airframe side that you recommend to help achieve a higher cruise speed?

[Clark in AZ]

What are you getting now? What engine, prop, other mods have you already done?

[Tralika]

The flap gap, elevator and rudder seals help with the airflow over the control surfaces and improve control in slow flight but I don't think it will help with cruise speed. The SuperSTOL and Highlanders are just not made for speed. I see in your profile you have 29" tires and of course that isn't helping either. I tried covering the landing gear on my Highlander and that didn't seem to make any difference but making a fairing to streamline the aft tube on the landing gear might help. If you can figure out a way to streamline the big SuperSTOL shock absorber I'm sure that would help. The Jury Struts and flying wires on the tail are big drag producers as well. Replacing the wires with the streamlined solid type might help but would probably add weight. There's a company called Old School Aero in New Zealand that makes them but I don't know anything about them except what is on their website. I think your best bet would be to experiment with your prop pitch. Adding a bit more pitch to the prop will improve cruise speed, the trade off will be less power for take off and climb. There are in flight adjustable props available now and I'm told that makes a big difference in cruise speed but of course would be a big investment. Let us know if you find anything that works. We'd all like to have a bit more cruise speed as well.

[BDA]

As was posted - prop is the easiest fix for speed.
Symetrical airfoil tail is faster.
Extreme windshield will give you a little speed.
Allen Ronk in Australia made a bunch of speed mods to his Superstol and his cruise was much faster. He had fairings on everything.
I have heard that there were 0-340 XL SuperStol's that would do 130 mph.
I have only had mine to 120 with the Whirlwind prop at high pitch, not much for short take off like that tho.
Currently with 35" tires and 12' extended shocks and 24" extended wings and mid range prop pitch I am doing 95 mph at 2,500 rpm.
That is with no fairings.