Thread: Discussion HK EPO Parjet, ARF
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Old Oct 26, 2012, 08:58 AM
solentlife is offline
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222 km/hr Parkjet flyer
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Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
11,386 Posts
Once I have the twin flown ... I am honestly considering a mild PKJ ! Yes a stock one .... the 222 one is stripped to bare frame now after too many crashes and repairs trying to beat her old record. The later PKJ2 is in good 'uncrashed' order but is the basis for my twin attempt, the 4400kv and stuff are benched.

So thoughts came round to whether I should hit what I term the max thr PKJ is capable of ... then relax to more sedate sub 200 speeds !!

Just to recap ........ Twin is :

2 of 3800kv 250 heli motors
2 of 4.1x4.1 and 4.5x4.5 contra props
2 of 50A ESC's with separate BEC
3S 1800 and a 4S 1500 ... first run with 3S .. then if successful - we hit it with the 4S ... short run time and possibly ESC's will be on limits ... but should be interesting.
No gyro ... but serious D/R + Expo to keep her tamed.

Calculations based on my data sheet of actual results on prev PKJ's indicates a possible speed of about 250kph with 3S and over 285kph with 4S ...

One aspect that is troubling is how to catapult ... it indicates a dead launch and only AFTER exit the rails to engage motors ... due to props striking rails if turning. This worries me because of 'panic' pushing stick fwd .. it would be too easy to push throttle too far too quick ... as it's only a matter of a second or two between exit rail and demand for power ...
I'm trying to figure out if I can design a wire cradle that lifts it enough to allow props to turn ... slide up the rails ... drop away without having prop strike ...
Initial thoughts are a cradle that is actually attached to the bungee ? That all models in fact could use ...

Ideas / sketches anyone ?

Knees are trembling already !!

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