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Old Aug 20, 2012, 11:05 AM
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Finlande
Joined Dec 2007
422 Posts
Yeah Solentlife, your setup is a bit crazy but will be fun for sure . Motor choice seems good but not for 4 cells cause amp draw would be too high .

You"ll need a big 3 cells battery to cope with the power . My setup runs a bit under 600 W with 37 A on 4 cells and is good for a solid 210 kph .

If you intend to break the 220 , you"ll need far over 700 W so I am curious to know what battery you are planning to use ?

My Parkjet 2 is ready . I maidened it with 3 and 4 cells and all I can say is that this plane flys even better than I remenbered . Launches with motor flush with the wing makes them a non event .6 flights and I couldn't see the slightest torque effect at launch either on 3 or 4 cells .

I think I was in the low 190 kph by using a 4S-1300-45C battery that can't get me any faster . The fuse hadn't any reenforcement and I didn't dare to try the Turnigy 4S-1300-30C which should make me break the 210 kph barrier again .

My fuse is rock solid with a thick 5 mm CF spar in the wing just behind the servos and two 3 mm CF spars sticked inside the fuse from front almost to the back .

Tons of fun in that little plane for very cheap .

Waiting to see your new little beast coming up Nigel
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Old Aug 24, 2012, 12:23 AM
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Joined Feb 2010
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How about canards?

I wanted a canard jet, so I put some on the parkjet



And yes they are full flying. With the canards top speed handling is about the same, but low speed handling is definately improved. - I also kept the CG the same since I was flying already nose heavy, and the canards are relatively small.
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Old Aug 24, 2012, 12:54 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 catspider View Post
I wanted a canard jet, so I put some on the parkjet



And yes they are full flying. With the canards top speed handling is about the same, but low speed handling is definately improved. - I also kept the CG the same since I was flying already nose heavy, and the canards are relatively small.
Cat that looks wicked man.just wondering where did you find space for 2 servo's for the canards?
can you post a pic with the canopy off please.
Love your idea
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Old Aug 24, 2012, 11:53 AM
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Joined Feb 2010
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I may have phrased that wrong, its an active canard not full flying - mixed in with the elevator channel, and mechanically tuned to give about 2x as much up movement as down. It only uses a small 9 gram servo (thats all i had lying around) Also i did not keep the CG the same, what i meant to say is that i did not change the battery location, as the extra servo and linkage added enough weight in the nose to compensate for the extra wing area up front. - really should not post when tired

here is a blurry photo:



here is a bigger photo:

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Old Aug 24, 2012, 12:20 PM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
9,043 Posts
Great ... I love to see innovation !!

My new project is delayed due to losing one prop adaptor !!

I posted about canards about a year ago and had no response - so left it alone. My idea then was to re-use some of the spare flybar paddles I have from my 450 heli ... just re-shape a touch.
They are threaded to fit the flybar rod and would have similar set-up to yours - an axle through the fuselage and single servo actuation. I have some 4.5gr micro servos ... ideal.

Nigel
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Old Aug 24, 2012, 02:35 PM
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Quote:
Originally Posted by solentlife View Post
Great ... I love to see innovation !!

My new project is delayed due to losing one prop adaptor !!

I posted about canards about a year ago and had no response - so left it alone. My idea then was to re-use some of the spare flybar paddles I have from my 450 heli ... just re-shape a touch.
They are threaded to fit the flybar rod and would have similar set-up to yours - an axle through the fuselage and single servo actuation. I have some 4.5gr micro servos ... ideal.

Nigel
What i did, is use a 4mm carbon rod, through two pieces of nylon tube glued with hot glue in the fuse, then hot glued the rod inside the 6mm foam canards. For the actuator lever i just took a control horn identical to the one on the servo, enlarged the center hole and drilled a small side mounting hole for a pointy self tapping plastic screw. With shaping the canards the whole process took about 30 min of work, however its super stiff and super accurate since all the parts are tight fitting.

After flying 3 batteries on this setup, i cant really imagine the plane without canards. I flew with them off too, since they are on a switch, but its just not the same as having them active when you slow down.
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Old Aug 25, 2012, 02:12 AM
Reap the wild wind
headlessagain's Avatar
Bristol,UK
Joined Feb 2007
4,294 Posts
Nigel
for your twin, have you thought about a puller/pusher setup? RCFoamFighter had a modified SkyFighter2 with this configeration. Might make it easier for c of g setting
Andy
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Old Aug 25, 2012, 02:23 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 headlessagain View Post
Nigel
for your twin, have you thought about a puller/pusher setup? RCFoamFighter had a modified SkyFighter2 with this configeration. Might make it easier for c of g setting
Andy
Hey that's a cool idea...
cat I love your canard conversion,though the PJ is super stable at low speeds.
NEED to get a new kit.assessed mine and it's pretty toast....
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Old Aug 25, 2012, 03:47 AM
222 km/hr Parkjet flyer
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Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
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Quote:
Originally Posted by headlessagain View Post
Nigel
for your twin, have you thought about a puller/pusher setup? RCFoamFighter had a modified SkyFighter2 with this configeration. Might make it easier for c of g setting
Andy
The reasons for the twin idea :

a) To have contra rotating props and eradicate torque on launch / flight.
b) To lessen effects of losses we get when only one prop ... same as powerboats with twin props ... effectively gains a slight increase in speed / control.
c) To counter the weight of serious battery power and twin ESC's

As you see there is a definite logic behind the twin pusher idea ... which once I get my parts will be finished and tested. I'm just annoyed that it's taking so long to get to flight ... now I've changed job - I hope to have more time at home ...

Nigel
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Old Aug 26, 2012, 10:13 PM
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Joined Mar 2012
78 Posts
here it is! pkj3 and no decals other than duct tape and fiber tape to help protect and discern the top from bottom. it's dialed in on pkj2's channel in the tx which means i'll be trimming both plans in the air and will have to record the trim #'s for each pkj.

now at least i can attempt 2 flights on each pkj and 2 flights on the funjet...this makes setting up the bungee launcher worth while. i haven't been flying the funjet mostly for that reason. i have 2 batteries for each of these birds,so if no crashes I'll gain lots of speed adreilin.... i just this moment decided to ask my daughter to accompany me to the field to be my photographer and the second person required as the club rules requires. so maiden may be this week.



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Old Aug 27, 2012, 02:53 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
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I note the use of hold-down bolts at sides of canopy ! It's amazing the stiffness that gives that part of the frame. My bolts are little more fwd than yours to try and cure that weak point at front of main wing joint.

I want nylon bolts but not available locally ...

Good luck Stu ...

Nigel
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Old Aug 28, 2012, 11:35 AM
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Finlande
Joined Dec 2007
422 Posts
I finally got to fly my Parkjet 2 .

My setup is the same as before . This motor :

http://www.giantshark.co.uk/2217-270...-p-402979.html

with a 40A mystery ESC

Turnigy 4S-1600-30C

I first got a bit disappointed when flying the two first batteries because I got twice 196 km/h with an 4,75x4,75 APC prop .

It was fast but I could feel that it didn't go as before .

I then tried a brand new battery and this time I managed to get to 204 km/h .

That was fast but I could get to 214 km/h with my first Parkjet using a 4,75 x 5,5 prop . This 4,.75 x 4.75 prop isn't up the task .


I noticed a certain kind of sensitivity on the roll axe that wasn't on my first Jet .
I wonder if the motor positionned even farther back ,helping so to achieve a correct CG, may be responsible of that . It makes it even more scary and I had to tame the beast with almost 100 % expo .

I was doing my last flight when all of a suddeen I saw the plane exploding while going WOT for a while .

The motor mount Gorilla glue didn't make it and motor went alone straight ahead pulling all electronics all around and plane went down totally empty except of servos .

I found motor, receiver, ESC and battery and amazingly, nothing got damaged .

Plane was going 204 km/h ( checked on the pitot tube memory of the last highest speed) and hardly got any scratch . Good thing it was empty when crashing .

Morality guys : eject your electronics and pilot before you crash !

This plane is a real blast . Waiting to hear about more flying reports .

What happened to the two guys that were using the Don's 3000 in their plane ?
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Old Aug 30, 2012, 09:53 AM
222 km/hr Parkjet flyer
solentlife's Avatar
Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
9,043 Posts
Having had PKJ1 motor stick start to work loose on me before - I never trust anything except Epoxy for these machines. In fact Epoxy is my glue of choice for most things except traditional wood build.

And as many know - I now fabricate my own motor mount from metal L plates - only way motor will do as yours Jpette - is if the whole back-end breaks away !

My biggest problem now is the crap flying area we have .. the bungee straddles the whole width of the cut area - meaning that the 1m high long grass around is a hazard. I'm really reluctant to launch her there. And with the power that's installed in mine - forget hand-launching ...

Nigel
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Old Aug 30, 2012, 01:56 PM
222 km/hr Parkjet flyer
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Latvia, Ventspils pilsēta, Ventspils
Joined Jan 2010
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Here's the field as tonights session ....
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Old Aug 31, 2012, 07:10 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
Here's the field as tonights session ....
That's ample space enough to launch 10 PJ's at once
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