Electric Stunt > Gettin all AMP'ed up!

eParrot XL with Himax Contra

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Matt Piatkowski:
Hello,
Please see the attached.
This is eParrot XL 90% ready.
I have used the wing from the original eParrot built in 2017, extended it (old wing: 550 in^2, new wing 600 in^2) and added a new, longer fuselage and empennage with the horizontal stabilizer and elevator based on the Max Bee II geometry.
 
More details are available upon request.

The model will weight about 1530 grams RTF with Himax 3516-1030, 4S 4000 TP battery, Fiorotti active timer and two carbon laminate propellers (one is 11x5x3 from Igor Burger, the other is 11x6 PolProp).
These combination of propellers decreased the noise just before take-off from 93 to 86 dB, measured by the FAI rule.

I expect to further improve the pattern flying this model as, like I wrote before, the contra system offers three major advantages over the single propeller system.
Happy Flying,
M


 

Dennis Toth:
Matt,
Nice ship, interesting set up. Once you start flying please let us know the details on the line length, lap time and rpm.

Best,    DennisT

Matt Piatkowski:
Hi Dennis,
I hope to flight test the model before the end of October.
I am currently working on mounting of the electric and electronic components and covering of the fuselage and empennage.

I am using felt- tip water-ink markers to color lightly sanded bare balsa and Doculam goes on top. This is the lightest finish of the model I have found.
Doculam never goes slack when exposed to summer sun and is much lighter than Monocote, Ultracote and other, heat shrinkable, "cotes".

Regards,
M

Randy Powell:
Seems an interesting project.

Matt Piatkowski:
I am pleased to annouce that eParrot XL made six flights (4 trimming flights and two full patterns) yesterday.

Span: 56.375", unequal panels (1" difference)
Wing area with flaps: 615 in^2
Flaps: full length
Thin horizontal empennage based on Max Bee II geometry (scaled down to 92%). 1 mm. dia carbon tube was used for the stabilizer's LE.
Hinge to hinge distance: 18.125" (2.875" more than in original eParrot) - gaps sealed.

RTF weight: 54.93 oz. with:
- Himax 3516-1030 Two-Motors-in-Tandem (TMT) power plant
- 4S 4000 mAh TP battery
- Two Jeti Spin PRO 40 Amps. ESCs
-  Rogerio Fiorotti active timer (the active function of this timer does not work with Spin PRO - I will get Jeti Spin F2B ESCs - they work properly with Fiorotti's accelerometer and timer)
- 11x5x3 Igor's F2B carbon propeller (in FWD position)
- 11x6 PolProp from Tomek Jadczak (in AFT position)

The wing's loading: 12.86 oz./ ft.^2 - this is within the so-called "Yatsenko's F2B Range": 12.6 - 13.6 oz./ ft.^2.

Lines: 0.015", braided, 59 ft. from eye-to-eye.

Wing tip weight: 0.75 oz.

Lap times: 5.2-5.3 sec.

Flight time: 5 minutes and 10 seconds.

The model flies simply too well! I am, at this moment the Advanced Stunt flier and will for sure improve my pattern flying it.

All major functions: take-off, landing, level flight stability, grooving, tracking, cornering, looping, the overhead performance in the moderate wind (9 knots gusts) and wind penetration are exceptional.
This is the best stunt model I have ever flown.

I can only attribute this to the flight dynamics of the Contra powered stunt models and good aerodynamic properties of the model's geometry.

Lastly, I did not have to modify anything in the model's setup: the leadouts position, wing's weight, rudder's angle, C.G., lines spacing...all stayed as set up before the first flight.

I have measured the noise on the ground (hard surface) following the FAI rules - it was 86 dB. With two propellers having the same number of blades (2), this noise is 92 dB.

Both noise levels are acceptable during the european contests but of course 86 dB is less annoying for the judges and spectators.

The model has many unique structural and geometric solutions and I am considering publishing the plans of it.

Stay Safe, Happy Flying,
M 

 

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