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Old Apr 04, 2012, 09:09 PM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,807 Posts
Just had the PJ out after tweaking last night and got these speeds with rcspeedo.
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Old Apr 05, 2012, 02:13 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,807 Posts
These speeds were done flying cross wind, the wind and the sun were both in the same position, so I had to stay away from flying near the sun, at the end of the flight I made a bad turn and ended flying into the sun and totally lost it, all I could do was shut down and hope to see it again, but as the seconds ticked by I knew it was going end badly.

My flying buddy and I started looking around the saw the plane a fair distance away on the ground by a fence, on arrival at the crash site it was good to see that minor damage on the plane, sadly the canopy is the most damage piece and the hardest to repair.
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Old Apr 05, 2012, 04:10 AM
Registered User
Finlande
Joined Dec 2007
422 Posts
This small plane is a real blast above 160 km/h .

I read about one guy on H.king website using your motor with a 4,75x4,75 for a 36 A burst .

That should push it in the 180 km/h range.

You can also get much higher speed using better batteries .
I get an extra 10 km/h by switching from Turnigy 4S-1000-30C to nano-tech 4S-1300-45C .

Did you reinforce your airframe ? I can hear a huge vibration in the whole airframe at a certain speed in the 150 km/h range. I just need to pass it and all is well .
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Old Apr 05, 2012, 05:07 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,807 Posts
Quote:
Originally Posted by Jpette View Post
This small plane is a real blast above 160 km/h .

I read about one guy on H.king website using your motor with a 4,75x4,75 for a 36 A burst .

That should push it in the 180 km/h range.

You can also get much higher speed using better batteries .
I get an extra 10 km/h by switching from Turnigy 4S-1000-30C to nano-tech 4S-1300-45C .

Did you reinforce your airframe ? I can hear a huge vibration in the whole airframe at a certain speed in the 150 km/h range. I just need to pass it and all is well .
Yea I heard that to about reinforcing the airframe but all I did from the start was to put a small carbon spar through the centre section.
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Old Apr 05, 2012, 05:13 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
8,463 Posts
The main thing to strengthen are the elevons ............ they are flimsy and will likely flutter or fail at extreme speeds.

I will be replacing mine with balsa versions later.

I have laid longitudinal wood strips along fuselage bottom set in after seeing stress cracks appearing in the paintwork etc. It also allows me to anchor the lipo velcro strap.
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Old Apr 05, 2012, 05:17 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,807 Posts
Quote:
Originally Posted by solentlife View Post
The main thing to strengthen are the elevons ............ they are flimsy and will likely flutter or fail at extreme speeds.

I will be replacing mine with balsa versions later.

I have laid longitudinal wood strips along fuselage bottom set in after seeing stress cracks appearing in the paintwork etc. It also allows me to anchor the lipo velcro strap.
Already replaced the elevons with balsa ones, thats why they are covered in red film.
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Old Apr 05, 2012, 09:06 PM
Free as a bird now.
Brian Courtice's Avatar
United States, FL, Punta Gorda
Joined May 2002
6,603 Posts
I tried out RC Speedo on my Parkjet today. It worked great! I only used it on one flight, until I filled up the first page on the log. My fastest pass was 108 mph. (168 kph). My average speeds were in the mid 90's. (145-155 kps.) Cool! I was happy to confirm that my plane was breaking the 100 mph mark.

I did have an interesting thing happen later on. A bad launch ended up with the plane on its back and one of the vertical fins broken. I lost about a third of the fins area, but otherwise it was still attached. Everything else was OK, so I went ahead and flew it like that.

Once airborne, it needed quite a few clicks of right trim, and I could see the model fish tailing slightly on yaw. The overall handling was not great, gone was the "flying on rails" feeling it had before. However, it was flying , and I kept going.

A series of climbing fast rolls got a little squirrely and barrelly, and then turned into a flat spin. Whoa, that never happened before! I had lots of altitude, and after a few rotations, I recovered and kept flying. The next time I tried multiple rolls, it happened again. This time the transition to a flat spin was more violent. It was sort of a snap roll into a spin. Despite having lots of altitude, it spun all the way in. I had plenty of time to try rolling out with aileron, pitching out with both up and down elevator, and powering out with blips of throttle, but nothing stopped the flat spin.

Fortunately, the flat spin did slow the planes decent, and it landed on grass with almost no further damage.

I've heard of other pusher jet designs doing this, but this was the first I've seen or heard of it happening with a Parkjet. I guess the moral of the story is, you need all of the fin area you've got! I'll repair the broken fin and fly it again soon.
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Old Apr 06, 2012, 03:55 AM
how'd I do that....oh
chop stiX's Avatar
South Africa, GP, Pretoria
Joined May 2011
2,260 Posts
Quote:
Originally Posted by Brian Courtice View Post
I tried out RC Speedo on my Parkjet today. It worked great! I only used it on one flight, until I filled up the first page on the log. My fastest pass was 108 mph. (168 kph). My average speeds were in the mid 90's. (145-155 kps.) Cool! I was happy to confirm that my plane was breaking the 100 mph mark.

I did have an interesting thing happen later on. A bad launch ended up with the plane on its back and one of the vertical fins broken. I lost about a third of the fins area, but otherwise it was still attached. Everything else was OK, so I went ahead and flew it like that.

Once airborne, it needed quite a few clicks of right trim, and I could see the model fish tailing slightly on yaw. The overall handling was not great, gone was the "flying on rails" feeling it had before. However, it was flying , and I kept going.

A series of climbing fast rolls got a little squirrely and barrelly, and then turned into a flat spin. Whoa, that never happened before! I had lots of altitude, and after a few rotations, I recovered and kept flying. The next time I tried multiple rolls, it happened again. This time the transition to a flat spin was more violent. It was sort of a snap roll into a spin. Despite having lots of altitude, it spun all the way in. I had plenty of time to try rolling out with aileron, pitching out with both up and down elevator, and powering out with blips of throttle, but nothing stopped the flat spin.

Fortunately, the flat spin did slow the planes decent, and it landed on grass with almost no further damage.

I've heard of other pusher jet designs doing this, but this was the first I've seen or heard of it happening with a Parkjet. I guess the moral of the story is, you need all of the fin area you've got! I'll repair the broken fin and fly it again soon.
that sounds funwheres the vid?
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Old Apr 06, 2012, 04:46 AM
Free as a bird now.
Brian Courtice's Avatar
United States, FL, Punta Gorda
Joined May 2002
6,603 Posts
I wish! There's never anyone taking video when you really need it...
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Old Apr 06, 2012, 07:13 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
4,807 Posts
Quote:
Originally Posted by Brian Courtice View Post
I tried out RC Speedo on my Parkjet today. It worked great! I only used it on one flight, until I filled up the first page on the log. My fastest pass was 108 mph. (168 kph). My average speeds were in the mid 90's. (145-155 kps.) Cool! I was happy to confirm that my plane was breaking the 100 mph mark.

I did have an interesting thing happen later on. A bad launch ended up with the plane on its back and one of the vertical fins broken. I lost about a third of the fins area, but otherwise it was still attached. Everything else was OK, so I went ahead and flew it like that.

Once airborne, it needed quite a few clicks of right trim, and I could see the model fish tailing slightly on yaw. The overall handling was not great, gone was the "flying on rails" feeling it had before. However, it was flying , and I kept going.

A series of climbing fast rolls got a little squirrely and barrelly, and then turned into a flat spin. Whoa, that never happened before! I had lots of altitude, and after a few rotations, I recovered and kept flying. The next time I tried multiple rolls, it happened again. This time the transition to a flat spin was more violent. It was sort of a snap roll into a spin. Despite having lots of altitude, it spun all the way in. I had plenty of time to try rolling out with aileron, pitching out with both up and down elevator, and powering out with blips of throttle, but nothing stopped the flat spin.

Fortunately, the flat spin did slow the planes decent, and it landed on grass with almost no further damage.

I've heard of other pusher jet designs doing this, but this was the first I've seen or heard of it happening with a Parkjet. I guess the moral of the story is, you need all of the fin area you've got! I'll repair the broken fin and fly it again soon.
Cool Brian

So with a half reasonable set up the parkjet's can get close 100mph.
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Old Apr 06, 2012, 11:41 AM
rcflyer
UK
Joined Jun 2010
844 Posts
What is a good replacement motor from HK for some speed?!

Cheers
Jim
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Old Apr 06, 2012, 12:29 PM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
8,463 Posts
Any reasonable motor over 3500KV that is heavy enough to balance a decent LiPo ....
Problem is as you go up in KV to get the rpm - you need the LiPo sufficient capacity, C rating to give the punch and run-time. This means heavier than the small 800 / 20C jobs.

EDF / Helicopter motors are good candidates ........ BUT get rid of stock mount and fit a decent alloy mount as in Hobby King onto the 10mm square stick beam. The composite miunt as supplied is not man-enough for the job.
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Old Apr 06, 2012, 12:36 PM
Free as a bird now.
Brian Courtice's Avatar
United States, FL, Punta Gorda
Joined May 2002
6,603 Posts
I am using this motor:
http://www.hobbyking.com/hobbyking/s...idProduct=8480

And this mount:
http://www.hobbyking.com/hobbyking/s...idProduct=5307

Turnigy 1300 25-25c batteries, 4.5x4.5 prop. 100+mph setup.
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Old Apr 06, 2012, 12:54 PM
rcflyer
UK
Joined Jun 2010
844 Posts
Cheers
Brian, do you recon your motor will balance with your motor and 1500mah 3s or 1000mah 3s? - This is all I have!

Jim
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Old Apr 06, 2012, 06:27 PM
Registered User
tobydogs's Avatar
Joined Mar 2012
78 Posts
intertesting day at the field,2 bad tosses by the same guy resulted in these damages. i thought the first toss was bad but the second was woorse...a little epoxy and will be good to go

bad news is the safty officer dosn't seem to understand bungee launchers and discourages it's use if more than 6 pilots are at the field flying. thats a small crowd on a weekend. after the wing is fixed,i'll practice with the launcher at a ball field where i will land right away. videos of today stunk and the one of the guy throwing the jets wasn't worth copying.
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