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Nov 08, 2013, 05:13 AM
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my speedmodels, their drives and their props

After more than 10 years of speed flying I believe, that with the 2019 result the right time has come for me to stop competition flying.

2019 was a particularly successful year:
Max von Prondzinski was able to reach 494.1km/h with the Hypercrocoblade I and thus further improved his 2018 world record in the FAI class F196 (481km/h).

At the PCSC 2019 the team pilots Stanley Spichtinger with his "Hellraiser" with "Powercroco"-motor and prop reached 640km/h in one direction and Tim Moldtmann with his "Typhoon-xl-ultra" with "Powercroco"-motor and prop 623km/h in the "open" class.

And at the German Championship in speed flying in September 2019 in Ballenstedt, pilots with "Powercroco"-motors won in all 4 electrically driven classes (2x heli and 2x wing).
In the wing models Tim Moldtmann won both titles with models that he took over from me. ("Crocoblade" and "HCB I")

For 2020, I had planned a last attack on the existing FAI speed world record F196 at the PCSC with 2 top pilots and the "Hypercrocoblade".
Now it turned out completely different than I had thought. "Corona" has more or less cancelled the whole speed season 2020 and therefore this last project.

For myself I have decided to fly from now on just for fun. So no more speed flying but gliding again.
But for "my" pilots I will continue to build engines and propellers as long as they need them.

Looking back on the past years, I can say that it was very interesting to help shape the further development for some time and to be there when the limits of what is possible were pushed further and further.
It was especially fun to prove that many things which, according to "experts", cannot work in speed flying or are bad or nonsensical, actually work perfectly.
This applies especially to the use of outrunner motors with high torque and low rpm with particularly quiet and extremely high pitched multi-blade propeller systems in speed flying.

Translated with (free version)
Last edited by powercroco; Dec 27, 2021 at 12:29 AM.
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Nov 08, 2013, 09:58 AM
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One of my personal projects for the 2014 speed season was the second "bird of paradise".
it fits into the rules of german national "limited" speed-chart.
it was a chimera again:
the fuselage comes from eagle-T, built by marcus koch,
the elevator comes from Teaser f5b, built by niklas kahlich,
the wing is foam-carbonfiber-balsa sandwich, (built in the "ninja way" ) by sascha wendt,
the motor is a 4530 evo based on scorpion prototype.
motorcode: 12N10P4530evo5+4 x 1,7YY

it was fired by 6S 3300 (limited) to 4200mAh (open).
esc was yge 160FAI - good for >200amps > 10sec (tested in real).
airscrew is my 13x31,5 folder as shorted 3 blade config.
with less than 10000rpm good for 400km/h.

wingspan is 140cm, lenght 125cm.
FAI wingarea is 33,4dm^2, good for 2500grams. n spec: 610/V
Last edited by powercroco; Jul 01, 2020 at 08:41 AM.
Nov 08, 2013, 10:45 AM
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Sweet Is the 1.7 in the motor code the diameter of the wind wire? I am getting ready to rewind my motor with larger wire and was going to go with 1.5mm.
How does it launch with that drastic a pitch. Marcus has been giving me some tips on setup for launching with crazy pitch numbers which includes setup in the ESC as well. My biggest fear is another prop stall incident
Nov 08, 2013, 10:55 AM
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yes, 1.7mm diameter wire is used.
in the motor tests i have loaded it with >250amps.

a launch of the 5kg (!) speeder peregrin with this 13x31,5 prop.

Over 400 KMH 245 MPH Speeder Pylon Peregrine World Record attempt in Ballenstedt on 14.09.203 (4 min 47 sec)

you easy can hear, when the prop gets full grip after acceleration.

I start my models alone everytime and never had problems to start with these props.

here you have a failed start (esc-problem):
Speeder Pylon Peregrine World Record attempt "failed start" in Ballenstedt on 14.09.2013 (0 min 17 sec)

nothing bad happened.

b.o.p. has the half weight of peregrin.
Last edited by powercroco; Nov 08, 2013 at 11:05 AM.
Nov 08, 2013, 11:06 AM
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You can really hear the different phases that the prop goes through in that first video that's some great stuff.
Nov 09, 2013, 01:56 PM
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SF - was wondering do you guys use any mixes for launch that play with camber at all just to give it a bit more lift?
Nov 25, 2013, 11:18 AM
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today the bird was maiden without any problems.
for the first flight I used a mild setup.
good for round about 60m/s climbing after acceleration and thrust-orientated.
speed was only about 250km/h. but good enough for 150m further climbing after cut of in vertical climbing.

Nov 25, 2013, 11:38 AM
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Was yoke a 0 degree for that graph?
Nov 25, 2013, 11:50 AM
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was a 3blade yoke with 0 degree and 53mm diameter in blade folding axis
Nov 25, 2013, 11:52 AM
300 mph club ;-)
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53mm yoke, 0 degree (see graph: 10"x17"B/53/0)!

Ciao, Marcus

Too late ;-)! Ralph was faster!
Dec 02, 2013, 12:28 PM
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today i tested the 11" x 20" /53 / 3blade folder.
one step more on the long way.

climbing was >60 m/s now.
had also about 200m climbing after cut off the motor.
speed is about 300km/h now with 11300rpm, amps went down from 140 to 105A after acceleration.
so there is a lot of room for further increase of prop pitch and speed.
Dec 12, 2013, 10:51 AM
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for real speeding it's to cold, but today I tried the 11,25x25 /53 3blade prop with 6S 3500 APL.
the voltage went down to 20V regardless of preheating the batteries.

climbing after the speedpass was 68m/s (4sec average).
because of in the last second the motor just was switched of, the 3 sec average; 70,8m/s
could climb really high because of the low clouds.

speed must have been about 330km/h (85% of pitchspeed at 10200rpm).
not bad for the low powerlevel (max 3,5kW)
Dec 21, 2013, 02:40 PM
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today the bird reached 9300rpm with the 12 x 31,5 /53 / 0 airscrew.
unfortunally the voltage went down to 19,23V because of the cold weather and often used cells .
for a "normal" voltage of 20,5V for 6S good batteries the rpm will be at 9900rpm and good for 400km/h.

can't wait to have warm weather again.....
Dec 21, 2013, 05:45 PM
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I am having a problem with cold batteries as well...have been putting them on the dash of the truck all the way to the field with the defrost on high/heat to preheat them but by the time I get them out of the truck in the plane and everything hooked up they cool down again.
Are the 12x31.5's 3 blade? What amps are you pulling with that setup?
Dec 22, 2013, 09:17 AM
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this 12" x 31,5" is 2 blade folder with shorted 13"x31,5" blades.
Amperage was up 190Amps ("switch on" peak).

climbing was good, still more than enough thrust for starting the bird alone.

in flight you have the same effect as shown into the "peregrin" video.
the props needs some seconds to get the full grip.
i can hear it and the flight log shows it too.

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