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Old Jul 15, 2012, 05:00 PM
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amba's Avatar
Joined Feb 2011
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Have HK had them in stock recently? I have not seen any over the past couple of months...
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Old Jul 15, 2012, 07:42 PM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,645 Posts
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Originally Posted by amba View Post
Have HK had them in stock recently? I have not seen any over the past couple of months...
Lol I bought 4 when they were in stock and afterwards thought I was crazy , now it seems a wise thing to have done lol, I dumb thumbed my first one a while ago and am now building 2 up. Leaves 1 in reserve.
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Old Jul 18, 2012, 01:45 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
Kits are in stock: +10 $14.95

http://www.hobbyking.com/hobbyking/s...kJet_KIT_.html
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Old Jul 18, 2012, 02:45 AM
Registered User
Finlande
Joined Dec 2007
422 Posts
Buddy code for the Parkjet :

http://www.hobbyking.com/buddy.asp?c...8-649A33A461C5

Solentlife

I finally ordered a new kit to get back on the race . As I told you before , I am now enjoying my water plane on the lake where I spend all summer in a cottage .

I was hoping for some new record from one of you guys but obviously, the 4400 kV motors are not up to the task .

Still waiting to be proven wrong but till today, all we have proven is that a 70g 3700 kV motor on 3 cells (like yours) or a 2700 kV on 4 cells (like mine ) will get you over 210 km/h . Forgive me but I am still waiting a confirmation of your 222 km/h speed record .

I still believe that high kV motors are a total waste of time because of the poor propeller efficiency due to a reduced small size and the need to use a larger ESC ( 60A min) that needs to be put outside ,spoiling the aerodynamic, and the lesser efficiency of a 3 cells system compare to a 4 cells one .

All the best guys to all of you and grab a kit cause only 15 left now.
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Last edited by Jpette; Jul 18, 2012 at 03:06 AM.
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Old Jul 18, 2012, 06:10 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,645 Posts
Been working on Parkjet 2 and 3, salvaged the canopy magnets from Parkjet 1 and am going magnet to magnet for the canopy. Really snappy when putting the hatch on lol.

Also going HXT 900's with 6mm larger balsa elevons.
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Old Jul 19, 2012, 11:28 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia / UK visits
Joined Jan 2010
8,323 Posts
Jpette ......

The problem as you know yourself - the over 210kph speed is extremely difficult to reach as the airframe is not designed for it.

The 4400kv was NOT a failure ... the problem was burning out ESC. The watts and thrust was unbelievable and IF it could have flown would have torn the wings of I reckon. I reverted to a lower motor and stayed in the 205 - 210 mark.
My 3700 had shot it's magnets and the replacement bent it's shaft, - the gyro was too high a setting and prevented me from controlling her ... she ploughed into long grass but sadly shaft bent. It's now fitted new shaft and in PKJ2 ready for it's outing. The gyro is sorted ...

I have to work and that takes me all over the world for weeks at a time ... I've just got back from a trip. Sunday we have a meeting and I hope that PKJ2 will finally show you that 222 is a reality. There's a whole group in my town who were there at the 222 but that's by the by.

Whether its volts or kv ... the end result is the same - to get rpm ... without rpm x pitch - you aint getting any speed. I can get 190kph on a 4.75 x 4.75 on a moderate motor ... 205+ on the 3700 .....

I am fully willing to concede if and when you beat me with the lower KV route ... but so far even my lower speeds are better than most peoples.


Wait till I get my next PKJ and fit the twin motors with contra props !!

Nigel
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Old Jul 19, 2012, 03:38 PM
Wats the worst that can happen
TheCure's Avatar
Canada, BC, Surrey
Joined Jan 2009
486 Posts
I'd like to know how the sorted gyro works out for you. I just built up a PKJII with a 2627 4100kv, 4.1x4.1, 3 cell + gyro. (i may try 5x5 later).

I'm looking for others answers before my maiden on these questions:
-is launching any different than stock if applying the same amount of thrust to take off? i.e. torque roll?
-does the gyro aid in countering the lauch roll?
-if the larger motor combos are just too difficult to hand launch conventionally, isnt it easier to hand launch almost straight up with a good toss? if it rolls..who cares



Quote:
Originally Posted by solentlife View Post
Jpette ......

The problem as you know yourself - the over 210kph speed is extremely difficult to reach as the airframe is not designed for it.

The 4400kv was NOT a failure ... the problem was burning out ESC. The watts and thrust was unbelievable and IF it could have flown would have torn the wings of I reckon. I reverted to a lower motor and stayed in the 205 - 210 mark.
My 3700 had shot it's magnets and the replacement bent it's shaft, - the gyro was too high a setting and prevented me from controlling her ... she ploughed into long grass but sadly shaft bent. It's now fitted new shaft and in PKJ2 ready for it's outing. The gyro is sorted ...

I have to work and that takes me all over the world for weeks at a time ... I've just got back from a trip. Sunday we have a meeting and I hope that PKJ2 will finally show you that 222 is a reality. There's a whole group in my town who were there at the 222 but that's by the by.

Whether its volts or kv ... the end result is the same - to get rpm ... without rpm x pitch - you aint getting any speed. I can get 190kph on a 4.75 x 4.75 on a moderate motor ... 205+ on the 3700 .....

I am fully willing to concede if and when you beat me with the lower KV route ... but so far even my lower speeds are better than most peoples.


Wait till I get my next PKJ and fit the twin motors with contra props !!

Nigel
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Old Jul 19, 2012, 09:09 PM
Gravity sucks.
Australia, QLD, Toowoomba
Joined Mar 2011
562 Posts
Quote:
Originally Posted by TheCure View Post
I'd like to know how the sorted gyro works out for you. I just built up a PKJII with a 2627 4100kv, 4.1x4.1, 3 cell + gyro. (i may try 5x5 later).

I'm looking for others answers before my maiden on these questions:
-is launching any different than stock if applying the same amount of thrust to take off? i.e. torque roll?
-does the gyro aid in countering the lauch roll?
-if the larger motor combos are just too difficult to hand launch conventionally, isnt it easier to hand launch almost straight up with a good toss? if it rolls..who cares
I can answer the torque roll on takeoff thing -> no, gyro's won't help (unless the wing is flying).

Because the wing on takeoff is stalled until it's up to airspeed, and the airflow over the 'flying wing' may even then be stalled BY the gyro if it tries to aggressively counter a torque roll effect.

i've been stalking this thread for a while now, and i'm starting to think the "wing" part of this plane is just there to keep the batt/motor/electronics moving through the air in a straight line!
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Old Jul 23, 2012, 02:44 AM
La Mesa Air
La Mesa, CA
Joined Mar 2010
307 Posts
Hello people!
I didn't see a better thread to discuss the HK Skyfun Jet, and it looks like it was previously discussed in this thread. I figured I would share my setup and ask a question.
So I've got a few upgrades on my Skyfun as you can see in the pix.

Power:
  • Turnigy 2836 2350KV outrunner
  • 6x4e APC pusher prop
  • Turnigy Sentry 60A ESC
  • Up to recently I've run a 3S2000, but now I'm running 4S2350 and 4S2800

Airframe:
  • Added carbon tube spars, each about 10", all gorilla glued in when I assembled the wings.
  • Balsa Elevons
  • Top mounted the servos and control horns
  • Hitec 65MG karbonite servos
  • Fixed landing gear - based on some eflite wheels and bent wire. I think the steerable nose wheel was a dubro kit or something.
  • Motor mount reinforced with a belly panel about 5" long. The actual metal mount on the top was drilled and tapped to accept #6-32 machine thread. The bottom panel is epoxied down giving a solid motor attachement.
  • Various other wood seen in the photos are more or less braces added after crashes to hold it all together.
  • Canopy is held on by a small dowel in the front, plus four magnets. None of the original plastic clips worked out of the box.

So with the 3S, I had measured by doppler about 80MPH. Last weekend I ran the 4S and borrowed a GPS logger, and got it up to 120MPH, although that includes slight dives.

One of my questions I've always had with this thing is where should CG be? Following the factory guidlines, the thing flew but was unstable, and lead to spins and high speed stalls. Now I have the CG pretty far forward. Currently I run it 2.5" back along the seam of wing and fuselage. That is about 1" in front of the root of the vertical stab. The way it flies now is a lot more manageable, but I always feel like I should be getting more elevon authority from it.

Anyhow, that's the rig. I'll have to get some video together for it soon.
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Old Jul 23, 2012, 03:22 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,645 Posts
Quote:
Originally Posted by kf6bbl View Post
Hello people!
I didn't see a better thread to discuss the HK Skyfun Jet, and it looks like it was previously discussed in this thread. I figured I would share my setup and ask a question.
So I've got a few upgrades on my Skyfun as you can see in the pix.

Power:
  • Turnigy 2836 2350KV outrunner
  • 6x4e APC pusher prop
  • Turnigy Sentry 60A ESC
  • Up to recently I've run a 3S2000, but now I'm running 4S2350 and 4S2800

Airframe:
  • Added carbon tube spars, each about 10", all gorilla glued in when I assembled the wings.
  • Balsa Elevons
  • Top mounted the servos and control horns
  • Hitec 65MG karbonite servos
  • Fixed landing gear - based on some eflite wheels and bent wire. I think the steerable nose wheel was a dubro kit or something.
  • Motor mount reinforced with a belly panel about 5" long. The actual metal mount on the top was drilled and tapped to accept #6-32 machine thread. The bottom panel is epoxied down giving a solid motor attachement.
  • Various other wood seen in the photos are more or less braces added after crashes to hold it all together.
  • Canopy is held on by a small dowel in the front, plus four magnets. None of the original plastic clips worked out of the box.

So with the 3S, I had measured by doppler about 80MPH. Last weekend I ran the 4S and borrowed a GPS logger, and got it up to 120MPH, although that includes slight dives.

One of my questions I've always had with this thing is where should CG be? Following the factory guidlines, the thing flew but was unstable, and lead to spins and high speed stalls. Now I have the CG pretty far forward. Currently I run it 2.5" back along the seam of wing and fuselage. That is about 1" in front of the root of the vertical stab. The way it flies now is a lot more manageable, but I always feel like I should be getting more elevon authority from it.

Anyhow, that's the rig. I'll have to get some video together for it soon.
Hi I think this might be the thread you are looking for.

http://www.rcgroups.com/forums/showthread.php?t=1163654
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Old Jul 23, 2012, 11:31 AM
ICrashRCs
United States, TN, Memphis
Joined Jun 2011
1,196 Posts
SkyFun CG almost to the front of the finger holes.
Put your fingers in the holes and move just back from touching the front edge of the finger holes.
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Old Jul 23, 2012, 12:54 PM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia / UK visits
Joined Jan 2010
8,323 Posts
Quote:
Originally Posted by m_ark View Post
I can answer the torque roll on takeoff thing -> no, gyro's won't help (unless the wing is flying).

Because the wing on takeoff is stalled until it's up to airspeed, and the airflow over the 'flying wing' may even then be stalled BY the gyro if it tries to aggressively counter a torque roll effect.

i've been stalking this thread for a while now, and i'm starting to think the "wing" part of this plane is just there to keep the batt/motor/electronics moving through the air in a straight line!
There's a difference ... my launches are via catapult launcher and I have recorded 113kph on exit of the rails. That is far higher speed than needed for the wing / control surfaces to have effect.
The wing is NOT stalled when launched ... with conventional launch - it has insufficient air-flow over it to have control authority .....

The reason I fitted a gyro is to counter the torque roll on launch of the catapult. It was never intended for hand launching as the model will not be stable in bank as the launcher sets up .. the gyro will be buzzing like mad ..

To "The Cure" ... my answer ... so far having a lot of trouble as the gyro is way too sensitive ... it's causing the wing to 'wobble' violently during launch. I have it really turned down but the PKJ is so sensitive to elevons ... I'm having to tweak very very carefully just up from zero !

I'm actually now looking at the Hobby King Flight Stabilization board :

http://www.hobbyking.com/hobbyking/s...dProduct=24353

at $18 and no messing about as I have with separate gyro .............

Yesterday the shaft adaptor gave out and prop shattered along with bending the shaft ....... so that put end to my PKJ play ... have now refitted the 4400kv motor while waiting for new shaft for the 3700.

Nigel
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Old Jul 26, 2012, 05:57 PM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
940 Posts
Rudder fin orientation

Just got my parkjets from hobbyking uk yesterday and just starting to put it together.

However I've noticed that the rudder fins are handed and not identical. Which fin goes in which direction?

Cheers,
Si.
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Old Jul 27, 2012, 12:40 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,645 Posts
Quote:
Originally Posted by SimonChambers View Post
Just got my parkjets from hobbyking uk yesterday and just starting to put it together.

However I've noticed that the rudder fins are handed and not identical. Which fin goes in which direction?

Cheers,
Si.
Flip a coin works both ways lol
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Old Jul 29, 2012, 06:37 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,645 Posts
Hobbykings new wing I want one, looks super easy to upgrade lol

https://www.hobbyking.com/hobbyking/...%5FPNF%5F.html
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