Pitts Special biplane – upgrade

[Predator]

After the less than successful first attempt at flying the recently acquired 800mm Pitts Special biplane, mainly due to lack of power, I have done a couple of upgrades.

The landing gear failed on the first attempt (after all our flying field [sheep paddock] is a tad rough) as did the bottom of the fuselage holding the landing gear attached.

The floor area has now been replaced with a slightly heavier grade of modelling ply and the wheel struts & wheels (larger diameter & width) replaced also. Hopefully strong enough now.

Now for the power issue.

Motor is an RC Smart EVO 1084kv outrunner swinging a 2 blade prop.

Original      –   8 x 4 prop – Output was 100W @ 8.4A WOT

Upgrade 1  –   8 x 6 prop – Output was 120W @ 10.oA WOT ~ Not much improvement

Upgrade 2 – 9.5 x 6 prop – Output was 140W @ 12.0A WOT ~ Slightly better

Upgrade 3 -11 x 7.5 prop – Output was 190W @ 17.0A WOT ~ Much better – almost double the output.

Bottom is original prop, top is current prop

 

Upgrade 3 is what I will be trialling but if its too aggressive I’ll get a 10 x 6 & try that.

Research has shown that the 850mm Eflite brand EPO foam Pitts Special, using an 880kw motor & 40A ESC (on 3S or 4S) spins a 11 x 7 prop so my selection should be in the ballpark.

 

Added a bit of Pitts branding (because I can) & she is good to go once the weather improved (hopefully)

 

 

[Hoppy]

CG should be about 65mm back from top LE. Wednesday forecast looks ok.

[Predator]

Yes, may be OK, light rain after lunch only & very light winds.

Could be a goer.

[Author]

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