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Old Sep 01, 2012, 12:02 PM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
8,411 Posts
Quote:
Originally Posted by chop stiX View Post
That's ample space enough to launch 10 PJ's at once
Trouble is my bungee is exact distance across that circle !! and that tall grass is tough stuff - you gotta see what it's doing to me leading edges !!

Nigel
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Old Sep 02, 2012, 03:13 AM
Glow 😡 no no no
Australia, SA, Evanston Park
Joined Mar 2010
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Quote:
Originally Posted by solentlife View Post
Trouble is my bungee is exact distance across that circle !! and that tall grass is tough stuff - you gotta see what it's doing to me leading edges !!

Nigel
Easy fix, double your bungee up for twice as much thrust over 1/2 the distance.
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Old Sep 02, 2012, 06:58 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
8,411 Posts
Quote:
Originally Posted by aeromaniac View Post
Easy fix, double your bungee up for twice as much thrust over 1/2 the distance.
Its doubled up now to 5m unstretched ....

To double up again will actually be counter productive as the advantage with length is the steady pull over a reasonable distance. This is waht is missed by the versions with bungee looped back under ramps etc. You get an intial short surge - but in first metre or so - it's over.
I get a good pull for at least 10m with my set-up.

Nigel
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Old Sep 04, 2012, 03:00 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 solentlife View Post
Trouble is my bungee is exact distance across that circle !! and that tall grass is tough stuff - you gotta see what it's doing to me leading edges !!

Nigel
Ok I get that
so cut a few meters more open...and voila,no more LE damage
any progress on the twin?pics please
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Old Sep 06, 2012, 07:04 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
960 Posts
After much faf (read, crash into the ground on launch), I've finally got my ParkJet flying.

Fly well it does! Just hand launching is a pain...

Unfortunately on its first flying flight, a sharp turn made the canopy shoot off and fall into the surrounding corn field. Had a good look but didn't really have a hope of finding it. They're combining it today, so it'll probably end up in someone's cornflakes.

Now I have a great flying plane, but no canopy - and HK don't stock replacement canopies. The cost of the complete airframe with shipping to the UK, is not far off buying a whole new ARF kit from the UK warehouse... Which I could do, but I'd still have a serviceable airframe with no canopy!

So I tried making one with a coke bottle, it (or I) failed miserably. Then I made one out of foam, which worked ok but cracked.

I'm tempted to give up on the canopy and fly it naked. Has anyone done this with any success? Or is the aerodynamics affected badly?

What have others done when they've lost their canopy?

Cheers,
Si.
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Old Sep 06, 2012, 07:31 AM
how'd I do that....oh
chop stiX's Avatar
South Africa, GP, Pretoria
Joined May 2011
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Quote:
Originally Posted by SimonChambers View Post
After much faf (read, crash into the ground on launch), I've finally got my ParkJet flying.

Fly well it does! Just hand launching is a pain...

Unfortunately on its first flying flight, a sharp turn made the canopy shoot off and fall into the surrounding corn field. Had a good look but didn't really have a hope of finding it. They're combining it today, so it'll probably end up in someone's cornflakes.

Now I have a great flying plane, but no canopy - and HK don't stock replacement canopies. The cost of the complete airframe with shipping to the UK, is not far off buying a whole new ARF kit from the UK warehouse... Which I could do, but I'd still have a serviceable airframe with no canopy!

So I tried making one with a coke bottle, it (or I) failed miserably. Then I made one out of foam, which worked ok but cracked.

I'm tempted to give up on the canopy and fly it naked. Has anyone done this with any success? Or is the aerodynamics affected badly?

What have others done when they've lost their canopy?

Cheers,
Si.
hahahahaahah.I just spat a mouthfull of tea all over my screen.hope they don't choke
That's a bummer man.It won't work without a canopy.p[lay aroung with shaping some foam to get it looking more or less.you could always order just a kit and keep the existing airframe as a spare for when the new one is toast and worn.believe me,one starts having waaayyyyyyy toooooo much fun and somewhere dumbthumb......
I still don't get the launch issue.
did you launch balls to the wall?
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Old Sep 06, 2012, 08:07 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
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Quote:
Originally Posted by chop stiX View Post
you could always order just a kit and keep the existing airframe as a spare for when the new one is toast and worn.
Problem is:
Kit - $43.05 inc shipping.
PNF UK warehouse - $58.69 inc shipping. But no stock at the moment.

So $15.64 more for servos+motor+ESC+prop isn't a bad deal, plus (if they had it in stock), it would get to me in a day or so!

For a similar price, there is the RadJet 800 which looks to have less launch issues than the Parkjet, plus is bigger. Or for not a lot more then there is the Skyfun, which even more performance can be got out of it.

Radjet 800 UK Warehouse - $65.89 inc shipping. $7.20 extra for something that is a bit different and is in stock.

I spent 2 hours carving a lovely canopy and then painting it. Then on an hand launch attempt it flipped over on to its back and smashed it.

I'm tempted to fly with no canopy and see what happens! What is the worse that can happen....?

Quote:
Originally Posted by chop stiX View Post
I still don't get the launch issue.
did you launch balls to the wall?
1/2 to 3/4 throttle on a 4.7 x 4.7 prop, 3S. I ended up doing test glides at low throttle over the corn to put enough right trim in, to get a fairly straightish launch. Still needs oodles of right trim to fly level.

I also changed to an alloy mount, which to be honest I think was a mistake, as it keeps on bending on impact. The next impact looks like it may fracture the metal and as I gorilla glued it in good and proper, it'll require major surgery to replace.

Cheers,
Si.
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Old Sep 06, 2012, 08:15 AM
how'd I do that....oh
chop stiX's Avatar
South Africa, GP, Pretoria
Joined May 2011
2,260 Posts
Just a kit is like $15 odd if I recall correctly.
I fly with 4.75x4.75 and launch full taps.though I have the mk1 which came with the 2700 kv motor.here are some early pics in the thread of mine.no problems with mount
http://www.rcgroups.com/forums/showp...6&postcount=20
The radjet is awsome,I wanna get one after I've completed my Flycat now and got a new PJ kit.got a wicked 3800kv motor I'm going to slap on that babe
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Old Sep 06, 2012, 09:00 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
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Quote:
Originally Posted by chop stiX View Post
Just a kit is like $15 odd if I recall correctly.
I fly with 4.75x4.75 and launch full taps.though I have the mk1 which came with the 2700 kv motor.
Yea $15 + $28.05 shipping. So by the time you've added shipping from Hong Kong to the UK, its only $15.64 difference (including shipping) from ordering the PNF in the UK Warehouse (the only version available in the UK warehouse atm). Also if you get stung with import charges from Hong Kong, that'll be more than $15!

If they had it in stock, I may consider buying another, but then I think I'll blow the cash on a Radjet. Shame as when it flew it was really good. I'm def going to give it a go with no canopy and some elastic bands to hold the battery on.
The only thing I'm bothered about, if it fails, is the battery pack. But even that is only worth $10!

Quote:
Originally Posted by chop stiX View Post
here are some early pics in the thread of mine.no problems with mount
http://www.rcgroups.com/forums/showp...6&postcount=20
The radjet is awsome,I wanna get one after I've completed my Flycat now and got a new PJ kit.got a wicked 3800kv motor I'm going to slap on that babe
Nice setup, looks more rigid motor mount setup than mine is now! I'm using the HK version of this - which they no longer stock. Not surprising as mine seems to be made of cheese! I did beef up the original mount with lite-ply between the support posts, changed it as others have said that the stock mount is rubbish. I wish I didn't now.
If the alloy mount breaks, I'll probably go back to the stock mount.

Might also try launching on full power too.

Cheers,
Si.
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Old Sep 06, 2012, 12:45 PM
Reap the wild wind
headlessagain's Avatar
Bristol,UK
Joined Feb 2007
4,075 Posts
Hi Si
glad you eventually got her in the air. Does it still need lots of right trim when gliding i.e. power off? If it does, then check the lateral balance to see if the plane cants over to the left and also check for any warps or bent fins. If glide is ok then you will need to adjust the thrust angle by inserting washers between the mount and motor.
Re your canopy.
Is it the surround and clear bubble or just the bubble? If its both then I would be tempted to build up tapered layers of 6mm depron and top it off with either a simple windscreen or look around the cosmetic/detergent aisle for a plastic bottle that looks promising.
My Parkjet is ready for the maiden using the 2600 kv motor from Giant Shark. It's the same set up as I ran on my HK Flycat so should have enough ooomph. Still need to build my Radjet and Rare Bear Funfighter. Getting my speed fix from my HK Seafury FF. Real easy to launch and very stable. Quite fast out of the box as well. I've also just bought a 2nd hand 26" wingspan balsa pylon racer for 24 delivered. Will swap out the brushed motor for a b/less unit. Might even run a BW 3000kv unit and go for a light weight build.
Flying on hold as the football players having taken over my flying field. The cheek of some people expecting to use the football field when I want to fly
Andy
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Old Sep 07, 2012, 03:03 AM
how'd I do that....oh
chop stiX's Avatar
South Africa, GP, Pretoria
Joined May 2011
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Simon I unsed the stock mount and just used 1.5mm piano wire epoxied into the foam and mount.ahhh sheit ya the shipping does kill abit.
As headless said maybe buidling up a canopy shouldn't be too much effort.
The trim issue in glide does not sound right.My pJ glides straight as an arrow(well it did before i toasted it)
Headless plug in the PJ and start screaming around low enough so dem footballers go play somewhere else
Oh btw maiden of flycat this week
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Old Sep 07, 2012, 07:59 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
960 Posts
Well I tried yesterday. Used a cut coke bottle held on with elastic bands as a canopy. First flight went ok - the prop did take a chunk out of the launchers fingers. Flew well, very quick and dead stable

Second flight - No success. Every launch it either went straight up and stalled or dived to the side. Ended up snapping the nose off and busting the alloy motor mount.

I reckon that every time the alloy mount was bent, it changed the thrust angle - even though I tried bending it back to its original position. I'll probably change back to the stock reinforced mount that I originally used. I've also just received some HK bungee cord - so I might use that to fling it into the air.

Probably end up being put to the back of the garage in the todo pile. Kinda given up with it now.

Cheers for the advice.

Si.
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Old Sep 07, 2012, 08:16 AM
how'd I do that....oh
chop stiX's Avatar
South Africa, GP, Pretoria
Joined May 2011
2,260 Posts
bad luck man.but i promise you it's worth getting that fine line right with this plane.it's heaps of fun and I have enjoyed it so much.I can't comment on the endless launch issue as I never had that.but then again my mate that launches for me has a very stable handhe launches perfect for me every time Gotta put dat order in for a new kit asap!
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Old Sep 07, 2012, 08:25 AM
Radio? Screwdriver!
United Kingdom, England, Bristol
Joined Aug 2011
960 Posts
Quote:
Originally Posted by headlessagain View Post
Hi Si
Does it still need lots of right trim when gliding i.e. power off? If it does, then check the lateral balance to see if the plane cants over to the left and also check for any warps or bent fins. If glide is ok then you will need to adjust the thrust angle by inserting washers between the mount and motor.
Yea it needs loads of trim when gliding. Lateral balance was fine when I built it and it's all straight and true. The thrust angle is probably all wrong, as every time it impacts the ground, it bends and alters the thrust angle!


Quote:
Originally Posted by headlessagain View Post
Flying on hold as the football players having taken over my flying field. The cheek of some people expecting to use the football field when I want to fly
Just seen that your in Brizzle! Why not come down to one of our (many) clubs and see about joining? All of them have good fields to fly from and no limits on electric flying. Certainly makes life easier flying from a dedicated field, especially on building/flying advice.

Cheers,
Si.
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Old Sep 07, 2012, 12:57 PM
Reap the wild wind
headlessagain's Avatar
Bristol,UK
Joined Feb 2007
4,075 Posts
Hi Si
looks like you have a bent fin or warp somewhere as the motor thrust angle won't be an issue on the glide
I'm in the Beaufort so have access to 4 club fields with my favourite being at Marshfield. I've also got the permission of the farmer to fly from her field on Lansdown which was the site of a English Civil War battle. The park is one row of houses away so great for a quickie before/after work. Only problem is pusher jets being noisy. HK Rare Bear and Seafury always get an audience but no complaints as nice and quiet. People don't seem to care about the 80 mph speed

chop stiX
yeah, I noticed your extremely bright EDF Flycat. Good luck with the maiden. Would be nice to buzz those footie players but don't want to risk a ban.
Andy
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