HK EPO Parjet, ARF - Page 54 - RC Groups
Thread Tools
Apr 13, 2012, 11:30 AM
Registered User
Originally Posted by amba
Today I finally managed to get a few consistent successful hand launches.

The factors I think contributed to success are-
1. Like Jpette said, streight, gentle toss (using my left hand, right hand on the elevons stick)
2. Transmitter programming to 'launch' position adds ~15 degrees elevons up reflex (see attached drawing). I cancel this once the plane is in the air using one of the dual-rate switches.
3. I used a relatively slow prop - 5.25x2.5, this helps getting better takeoff thrust. Even though this is clearly not the greatest choice for speed, I figured its better to first learn how to launch and only then work on speed

My setup now includes
* 30A ESC
* 1300mAh 3S 25C battery
* 60g 3500kv outrunner motor
* 5.25x2.5 prop
Glad that it is working fine for you too . The left hand launching technic is by far the most secure way .
Torque really shouldn't be a problem . Full throttle on 3 cells and it rips out of the hand .
your motor should get you to the 100 mph with a 4,75x4,75 . you"ll love it !!

I honestly enjoy it as much flying at 100 or 125 mph . With a lower speed I can keep the plane closer and make crazy rolls and loops .
At a higher speed, it gives an enormous thrill trying to hold on a perfect straight line .

This plane is by far my new favorite ; I still love my Rare Bear going about as fast if not even faster but the roar of that Parkjet at a high speed is a must .
I don't fly anymore my normal Stryker that feels so boring compared to this little beast .
Sign up now
to remove ads between posts
Apr 13, 2012, 11:49 AM
Registered User
amba's Avatar
Solentlife: There's some left roll when I launch it, but nothing I can't handle

Jpette: no argument regarding left hand launch, I've been using this technique for quite a while on all my hand-launch birds. no lost time hunting for the ailerons and elevator right after launch...
The funny thing is trying to find the dual-rate switch once the plane gains speed... since I just switched to a new transmitter, i don't have the instinct for these switches yet.. so I start flipping switches like crazy until I hit the right one ...
Last edited by amba; Apr 13, 2012 at 11:56 AM.
Apr 13, 2012, 12:59 PM
Registered User
gchrisgo34's Avatar
QUESTION, im getting ready to install this stick mount. im planning to use hot-glue, as i might want to take it off later. will hot-glue be strong enough? i have a fairly heavy motor and strong power setup? i dont have a lot of experience with hot glue, thats why i ask.
Apr 13, 2012, 03:09 PM
Registered User
I didn't put any glue . If you do so , put a very very little of it but only where you keep an access cause to remove it later, you"ll need to warm the glue first. No glue inside but a tad from the outside

Try first a very little tiny piece of tape like I told you and tighten the screw as much as possible and make a static test . It should hold on . If not and motor starts rotating on the left, then try the glue.

Also position your motor so that the wires come out from the left of the mount , touching the foam . Like that, wires stop the motor rotating on the left if it was to do so, and don't worry, motor is pushing on the plate that can't come out and if it was not tight enough, it will rotate very slowly and won't damage anything .
Last edited by Jpette; Apr 13, 2012 at 03:20 PM.
Apr 13, 2012, 06:21 PM
Registered User
tobydogs's Avatar
car is loaded for early morning runs at the club field. weather report is sunny,70 degrees,but 15mph winds. i hope to be flying pkj1 to warm up the thumbs. then its the maiden for pkj2 with the wicked 3000 motor. the bungee is ready to launch since its been tested ond works great. awesome even launching down wind if need be ,there should be a successful flights on pkj2 that has the v3 pitot speed recorder,and i may just try to have some one point and shoot the radar gun rather than set up the gun on the tripod with the keychain video camera recording fly bys..

i will be placing the video camera in someones hands to record the bungee launch,but the LCD video screen won't be usable in the daylight ,so hopefully the person will be able to follow along by just pointing the camera as i fly.

with a lil luck ,I'll have a bunch of bungee launches recorded,and a few flights on the pkj1,pkj2,funjet,and ajslick. should be a long day at the field.
Apr 13, 2012, 07:27 PM
Registered User
gchrisgo34's Avatar
jpette, im talking about the actual stick, not the part the motor screws to. im worried about using epoxy, as its pretty much a permanent thing. cant wait to see/hear how it goes toydogs
Apr 13, 2012, 08:29 PM
Registered User
tobydogs's Avatar

i would use epoxy on the stick. if you have to move or replace it you can. i just reset the stick on pkj1 as it was pointing to the side slightly. i just applied pressure back and forth till the epoxy started to release. removed the whole motor on the stick,sanded off the old epoxy with a dremel and re glued it right. she flys awesome with the 2 deg down thrust.

i wouldn't use any glue that might give way when you plan on hand launching these pushers. i get the feeling the strykers wouldn't have been given that name if the designers thought about the consequences of a bad toss.
Apr 14, 2012, 04:50 AM
222 km/hr Parkjet flyer
solentlife's Avatar
This is a serious piece of kit and anything other than a proper glued in joint is a no-no in my book. Imagine a motor deciding to come loose when a guys launching ?

The model is foam and removing / replacing mounts / motors is easy ... you can cut out .. square up area and glue in a replacement section of blue / pink foam ... $1 worth of foam insulation panel from DIY shop ?
Apr 14, 2012, 01:46 PM
Registered User
Ok Solentlife, start watching on your six cause I am coming on you .

214 km/h today with the 4,75x5,5

I just repositionned better my pitot tube that was a bit pointing downards and I got
209 and 214 km/h on the display with my turnigy 4S-1600-30 C

Not bad for a 2700 kV motor .

Unfortunately, I crashed the plane on my last flight .
Plane was nose heavy because of my heavier Rhino pack , wind was pretty strong and I suddenly lost sight of the plane that was too far . I released the stick and plane stalled in a death spin straight down from 100 m .
I tried to recover by adding power which made things evenworse and the plane hited the ground nose first and made a big hole in some thick mud .
The front part is totally smashed well beyond repair .

So Man, you can still sleep quiet for a while but remenber that in three weeks I "ll get a new one from H.King and I"m gonna make holes in the sky this time .

Now guys let's go flying and hopefully the Don's wicked will get you far above 200 km/h .
Apr 14, 2012, 02:48 PM
Registered User
gchrisgo34's Avatar
ill fill in for you while your gone jpette. ill be finishing my buid soon, with don's wicked 3000, 4cell. ill be moving in on solentlife's six. i dont have any way to check my speeds, but ill be there none-the-less.
Apr 14, 2012, 03:21 PM
Quad Erat Demonstrandum
scousethief's Avatar
Originally Posted by aeromaniac
Ok so is this going to develope into how slow can you go lol.

Been thinking of using one of these, with a 6a esc on 2s 350mah.

Interesting , i have plenty of those motors that i bought for a quad they are excellent but the windings are pretty fragile , for their weight they are pretty good on 2 cell but awesome on 3 ( when used on my quad swinging a 5x3 or a 5x3x3 ) think i better order some new batts lol.
Apr 14, 2012, 04:41 PM
Registered User

HK Parkjet "rc foamfighters style"

I worked on the parkjet today,

On the first run the motor got hot enough to melt the hot glue between the motor mount and carbon fiber rod causing the mount to slide all over the place until dry. So I used the a 250watt soldering gun and heated up the mount and slid it out easily and replaced the hot glue with a little gorilla glue. That made me want to make heat shields sooooo.

The first is a carbon fiber washer between the motor mount and the motor, which is basically the stock motor mount round piece, I just cut two bigger holes in it. Then I folded up a piece of foil and spray adhesive glued it right under where the motor sits to help protect the foam from extreme temps from the motor.

Then finally got a chance to do some legit motor test with the 4800KV.

Motor: Turnigy 4800KV
ESC: HK 90-100a
Battery: Turnigy 3S 1800 30-40C
Prop: 5x5E

I ran the motor for 1 minute before i did three 10 second pulls.

Max Power Results: 10 second burst

1025 Watts
102.5 Amps
10.0 Volts (sagged hard but still put out some juice!)

After the runs, the battery was at 12.13Volts...
The battery was warm, esc hot, motor hot. Im sure if the test went on then the battery would have gotten much hotter. So this battery put out ~56C for a short period of time.....go HK!

Before I go any further, Im going to come up with efficient lightweight cooling system for the battery, ESC and motor.

!!!EDIT!!!: Shaft No. 1, a 3mm shaft just warped at 1332 watts on a 4s nano(4.5x4.5). Balancing the prop & the 3.17 shaft is going in.
Last edited by morris.hans; Apr 14, 2012 at 06:46 PM.
Apr 14, 2012, 09:52 PM
Registered User
tobydogs's Avatar
sorry gang...i let ya all down.

flew pkj1 with the bungee launcher 3 times today and will post videos later. i didn't launch the pkj2 with the 3000kv wicked and 1600 30c 4cell very well at

i should have looked at the elevator setting on the already trimmed pkj1,the pkj 2 had way to much down set in for the launch,so my holding a little up elevator wasn't enough to keep from scooting along the ground breaking a control horn,the prop and the motor mount this really bugs me as it would have been my fastest flight to date.] pkj#3 will have the servo arms on top of the wing for sure.

i did fly the funjet ultra for the first time and all i can say is AWESOME BABY!

what a sweet flyer she is and i know it toped a 100mph,i was flying it when i asked a guy to use my radar gun,but he could get it working and i wasn't going to land to help,i was having to much fun to care. the other funny thing was the video of the funjet launch was my camera on a tripod behind me,but a fellow pilot using his cell phone maneuvered in front of my camera for the shot and blocked wife and i laughed at my luck with the video camerasheeeesh.
Apr 15, 2012, 01:00 AM
Registered User
gchrisgo34's Avatar
heres some of my latest mods. CF everywhere, including the leading edges of the elevons. stronger magnets, etc.... not sure i like the wing stripes, but oh well. time to start installing the electronics
Apr 15, 2012, 03:14 AM
Registered User

Awesome paint job .

I bet you"ll be using a 4,1x4,1 prop with your 3000 kV motor on 4 cells .

Will be interesting to see if you get better performances than my 2700 with a 4,75 prop . My bet is that you get the same performances with a solid 210 km/h . You will love it .

Do you have a speedmeter ?


Are you sure your 4800 kV motor will sustain such a heavy load even by proping down to a 4,1x4,1 prop ?

I killed a Turnigy 3S-1800-40C after 20 flights only by pulling 60 A out of it in my Stryker .
No battery can deliver it's max C rating very long and if you consider a 30C as a max , you get only 54A out of it . To go down to 54A , you"ll need a sub 4 inches prop .
Your motor looks like a nightmare to me but guy, this is the fun part of this hobby . Make more testing and I am waiting for your flight reports

Wishing you the best of luck.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Hobby lobby F9F Panther EPO Jet Receiver Ready ARF smasher41 Foamy EDFs 1309 Oct 19, 2017 02:23 PM
Discussion HK AT-6 Texan EPO Plug-n-Fly 29.5" w/s Stuart Warne Electric Warbirds 12 Jun 14, 2011 03:47 AM
For Sale HK Mini-PITTS -- EPO, Brushless, Plug 'n Fly WRXronald Aircraft - Electric - Airplanes (FS/W) 3 Aug 04, 2010 11:03 PM
New Product New HK Mini F-16 EDF Fighter Jet / EPO Plug-n-Fly CrashingDutchman Foamy EDFs 13 Jul 02, 2010 12:15 AM
Discussion HK's EPO F-16 WRXronald Foamy EDFs 5 Apr 11, 2010 03:47 PM