Hobbyking parkjet...need for speed!!!!!!!!!!!!!

[stuart]

don't feel alone,we all forget something every now and then.

i one day said my goodbyes to the gang at the field thinking i put my stuff away. got home and everything was there.....

except for the uproar,it was sitting on a flight table down the line from where i said my good bys. a quick return drive ,and a good laugh with the gang.

i also left my tx at the field when i had lawn darted my first hog bipe,guess i was preoccupied by the wreckage to remember it was under the flight table in the shade. took over a week to get together with a fellow member who had it for me.

[solentlife]

I didn't feel too bad when the guy who organised the trip actually forgot his as well !! But he was lucky that he could get to his Rx easily and re-bound to anothers Tx ..... FrSky of course ! In 1 minute we had his aux ch's in ..... of he went happy .... FlySKy of course !!

OK that's the plugs over ! The site was ok now but in summer will be impossible as it's disused and will overgrow with trees too close. Shame so far away as we could maintain it ...

[solentlife]

Today ....

Vilnis - who launched for the record run - was there to launch PKJ today ... we put in the 3S 1800 Zippy Compact ... tested motor - blew half the road dust over everything !

Vilnis lined up into wind ... me behind ........ Eagle tree V3 all set ...

1/2 throttle on the 550W set-up ......... he launched. She went straight and then dived into ground but SLOW !

I walked forward and picked up the PKJ .... bloody prop nut had come loose !! The landing had parted right wing joint. So that was all for today .....

BUT the launch was perfect until prop came loose.

Hopefully over next days - she will get another outing. I will change from the nice spinner like nut to a standard nut to prevent prop problem agaiin.

But I had a marvelous day ... see the 50mm Jpower thread in Ducted Fan ... and the Ultimate in Parkflyer ........

[dahawk]

I wonder if the PKJ uses the same prop adaptor as the HK Radjet. Mine came off as well. Very small dia. motor shaft, maybe 2mm but the threaded part of the collett adaptor looks like it's about 4-5mm. Lost my spinner the other day.

Will look at the Jpower 50mm thread as I'm getting ready to maiden the Red Arrows. Setting up expo's as you prescribed. I'll ask questions on that topic over there.

Good luck guys !

[solentlife]

Originally Posted by dahawk

I wonder if the PKJ uses the same prop adaptor as the HK Radjet. Mine came off as well. Very small dia. motor shaft, maybe 2mm but the threaded part of the collett adaptor looks like it's about 4-5mm. Lost my spinner the other day.

Will look at the Jpower 50mm thread as I'm getting ready to maiden the Red Arrows. Setting up expo's as you prescribed. I'll ask questions on that topic over there.

Good luck guys !

Mines a large shaft ... as it's a large motor !! Previously used a proper nut - this time went streamline with the spinner type ............ back to nut !

Hang fire .. still converting vids / doing doppler etc. on the T45 / Ultimate etc.

[stuart]

WEATHER FOR SATURDAY!!!!!! sunny!70 degrees! winds 10 to 15 mph! that equals 3 big smiles!

I'm glad i tested the bungee at a ball field so i know how quick a set up it really is. no question as to it's success in launching the pkj. the only issue might be the field will be crowed and when the tables[10 of them are filled with pilots setting up around the area i can expect 3 planes flying at any given time. the very best days to fly are during the week.

anyway,i hope to have a vid of pkj#2 with the v3 pitot readout of the speed for showing this weekend i at least get the 100mph award here at wattflyer. hope to get the run to put in the record book ,but won't be expecting 140mph. may setup the radar gun with a video key chain camera,or have someone try to point and record the speeds.

sad part is the bungee launcher won't fit the crowed fields use...so i may have to hang out till old folks go home...YES!!!!!!sounds like the perfect plan for spending a day at the field. other issue is the bungee launcher takes up to much space in the car where the hog bipe goes..






so i never hit the post button,i just got back from to ball parks i would fly at...dang kids!!! play and practicing base ball. whats with these kids...what ever happened to video games[jk] .weather is so beautiful that theres also a lot of folks walking the edges of the field. i dreamt of providing a video of pkj1 tonight. not going to happen.

so instead,I've loaded the car with pkj1 & pkj2,the multiplex funjet ultra,the bungee launcher,the ajslick.

i am topping off all batteries as i type and will have 6 batt's for the slick ,4,batts for pkj1, 2 4cells for pkj2, 2 4cells for funjet. if it's crowed at the field Saturday I'll fly a fraction of those batteries. can't fly Sunday do to plans getting in the way. lunch with friends.



JUST HEARD THE WEATHER REPORTS!yikesseriouse tornado warnings for the mid west. they say tornado's will happen for sure. i also heard our winds were to be 10 to 15......news just said 15mph. guys i don't care if i fly,i am praying for all our buds who are under the storm threat.

i will be leaving very early in the morning since the cars packed and ready. i should be able to set up for the pkj even before the glows are allowed to fly and get an end of run flight table....my hearts already racing.

[dahawk]

Will be rooting for ya Stu ! Can't you get the guys to give you the field for a moment for a bungee launch ? You'd think they would be interested to see this. Kind of like the NASCAR fans we have in our club. Once airborne, they can take off unless of course the rolling thunder of your PKJ screaming by on a high-speed low pass scares the crap out them.

No flying here this weekend. Big time Texas winds and storms. Oh, Spring time. Its to be expected. 10-15 here doesn't even get the wind chimes ringin.

Repaired the Radjet and am now waiting for the weather to maiden the Red Arrows T-45, inspired by my mentor Nigel.

Good luck and keep us posted !

-Hawk

[solentlife]

Here's the vid of the failed launch. As you see she went reasonably straight for about 10 - 15ft and then dropped like a brick. So I think the 1/2 throttle was about right .........

http://youtu.be/rfKUTnx-UAE

Unlike Stu - I'll have no trouble with a bungee ........... places we fly - I can lay out pretty well what I like.

Hey Stu .. 3 planes flying ? Even in days of Freq. Peg Boards - 1980's - at places like Beaulieu in UK - we'd have 10 or more up in air at one time ... like a hornets attack group !! With 2.4 now - I would expect even more ! 3's an empty sky .... Even with our small group in Ventspils ... all 6 of us .... we'll all be up in air at same time quite often.

Today is iffy weather ......... but maybe. Tomorrow weather looks good.

One of our guys has 35 ton of sand he wants to dump on rough ground to create a runway ............ as I asked him - What's owner of ground say ? Answer : Don't know, don't know who's owner ... but we've been flying there for years and no-ones ever said anything !

I can see 35 ton of sand doing a magic act of making owner appear !!

Sand - not exactly my idea of ideal material ... but it's free !

[solentlife]

While waiting for bungee to arrive ..... I decided to fit the hook ready. It may be a touch long but that will be cut back if necessary.

Pine beam, drilled, metal rod bent to fit, thread whipping to secure ...



Soldering iron formed slot just behind the air-in slot ...



Check fit ..



Epoxied in ...



Once all set-up - quick touch up with paint ...............

Note slight back angle ... this is to counter the ramp angle so bungee doesn't detach before actual launch.

[dahawk]

While you're at it, why not put in a pond. That way, you can tell the owner he now has beachfront property- I digress... Sorry

[solentlife]

It's up to them ... not really a location I like ... but lets see.

We go flying again tomorrow so hopefully have something to report. Yesterday was a waste of time - got to site and it poured with rain and wind came up with it .....
Been strong wind all day today.

Anyway - get back on the T45 / Hawk .....

[stuart]

todays flight report. i have several pkj1 launches on video,all successful. the sad part is no one was there to handle the video camera and be able to follow a fast plane....i wanted to set the camera on the tripod to get the launcher in view and hopefully enough sky to vid the flights....the flights are 90% above the view of the filming so no vids of my pkj flying. lot of sound of the motor.[ i love the sounds of these motors]

i somehow missed videoing the pkj2 launch. NOTE TO SELF:set elevator higher next time. she went straight down to ground level and scooted on it belly breaking the motor mount and prop. other wise easy repairs. i check the pkj 1's elevator as it's been trimmed out in the air and they were set higher .if i had known ,i would have set pkj2 the same way before launching.

the funjet took off the best of all,required only a couple of clicks to trim it for hands free trim......but while my camera was on a tripod to capture a perfect angle of the launch...a guy filming with his phone stepped in front blocking my camera[discovered at home...lol,to funny this camera stuff].

flew the ajslick 4 times,pkj 3times funjet once,and pkj2....well ,you know.

i will try to clip the vids of all the useless filming of chatter,and post the 3 launches including the funjet.

i have already charged batteries and hope to try again sunday evening if after lunch with friends and weather allows. all in all,a beautiful,windy,fun day of flying.

now to see if my better half won't miss me if i go to the shop to fix pkj's2 motor mount. NOTE TO SELF: don't call wife from firld at noon to say it's windy and i might be home early,and then hang out till 5pm....she missed me.

[solentlife]

Someone really hates me ... Vilnis asked me ... is that a large angle for engine ... I answered it has a large downthrust built in ...

We launched and exactly same as last one ... she went and then into ground.

Then we noticed - that Vilnis was right ......... motor mount was cracked and excessive downthrust ........... no wonder she's diving for the deck.

Motor mount is of with my mate Victor - the metals guy ... see if he can make a better / stronger job ...

Gives me time to get bungee and sort !!

But I flew my Cessna ... Ultimate ... had a ball .... !

[stuart]

after yesterdays launches,i would say your right to leave the launcher taller. i didn't cut mine down and the pkj/funjet drop as leaving the launcher only to immediately climb out.

i hope you have as good a time with your launcher as i am .so far it's 6good,one bad launch. the bad was pilot error due to control surface being set to low for down elevation.

heading to the workshop now to repair pkj2 and hopefully finish the foamy profile edge for ball park flying.

[solentlife]

I am really annoyed ............ PKJ and me ... just don't seem to work together.

Lets see what Victor comes up with on the motor mount.

Wasn't a good day for my T45 ........ showing off with my high speed grass cutting low passes ..... I fell foul of the no rudder problem ... I couldn't raise the nose when in a high speed turn and a small hump in the ground caught the wing-tip ............. Now I'm talking a mound of about 6" !! In fact the side of a tractor rut in the field ....... that was how low I was !! She cartwheeled under full power of a 4S ............... nose went in all directions followed by the LiPo ...........

Damage ? Nose crushed and snapped of. Rest of machine just flexed and cracked paint. New nose made and fitted ....... just doing the paint job.

[stuart]

hey nigel,whats going on with the alloy motor mount. i broke a plastic one the other day and replaced just now with an alum alloy one. even though it seems strong,it can be bent from side to side or front to back. it shouldn't deform in use,but on a rough landing i would have to be sure the down thrust is as it should be. i had an extra plastic mount and even though they break,they dont budge or twist once installed.i may swap the alum one out.

i also reglued a new control horn and adjust the elevator setting for more up....i would rather have to trim down in flight than watch it scoot the ground again. one plus to reinstalling the mount is the motor is further back,this will allow me to push the four cell foreward now to balance cg easyer.

lastly,i read the instruction for the v3 pitot installation and am concerned its very close[on top of ]to the rx. the instructions say it shouldn't affect the rx but be sure to range check. what do you think of the v3 being so close to the rx?i really like it snug up front and easy to read thru the canopy. i may have to install new tubes and push it all the way back since the battery leaves no room for anyhting else in its space. hope to maiden it this weekend.[shooting 30ft in front of the bungee launcher doesn't a maiden flight make]

[solentlife]

I had no trouble with the two close together ... I think they make "safe" statements to cover themselves.

I'll wait see what Victor comes up with on the mount, I'm wondering if theres a way to modify the CF one that comes with the kit ?

I've even thought about a domestic 90 deg metal shelf bracket so I can mount my small lighter motor and still balance. At least it will be strong !
My old motor weighs 72gr .... the lighter higher KV weighs 41gr ..... the EDF 5000kv at 54gr. So I have a reasonable margin to play with as I'm not including the old mount weight which is probably 5 - 6gr as well. I can also set thrist lines as I want ... height etc.

Right I'm of to the DIY shop have a loook at shelf brackets !!

[solentlife]

Well - no more weak mounts .....

Standard 2 x 40 x 40 domestic bracket



I reckon to insert UNDER the beam ...





Cut slot with soldering iron under beam ... then drilled pilot hole for small screw ....
Bracket marked and drilled for motor ....





Fitted by embedding leg under beam in epoxy and a small screw through into beam to harden up to align ...





I have the 5000kv EDF motor mounted on it at moment - but mount in fact is too light !! So May have to go back to my heli motor again.

[dahawk]

Nigel/Stuart,

Here's one for you. I saw this and could not resist. Take a $50.00 airplane, add a little bit of this and that and ?: http://www.youtube.com/watch?v=CZ4V7...2&feature=plcp

Holy Smokes !

[solentlife]

Well .... test run the 5000kv on a 4.75 x 4.75 ............. prop shattered ! The hub just gave out and threw blade ... and shaft snapped. I'm sure prop went first as the blade was seen to fly of and before I could shut down - the adaptor, other blade and shaft went flying !

So back to the 3700kv jobbie ....









Now I have a theory that the prop was coming loose because the mount was cracked from previous failed launches ........ Testing now with this DIY mount has proven that prop stays tight ............ and WOW ! full throttle just about cleared the area !!

Nigel

[stuart]

yikes! in another thread here at wattflyer i think i read of a prop throwing a blade and it stuck in the table or wall like a knife. I'm bummed to hear that motor didn't workout as i thought it would be very tough to beat. was that a custom cut prop or an emp 4.5x4.5 ?

the alum alloy motor mount i used will be run at least once and if its bent even a little after landing it will be either reinforced somehow or put in the round file. problem is i bought 3 of them when leader hobbies got them in stock. the small angle bracket looks great Nigel,and i know it's way stronger than the hobby shop bought mounts. i have to repair the bungee launch cause i tried to lift it and remove the 8" stake ,it broke a pc of the pvc. next time I'll lift closer to the stake. the ground around my field is very dry as we haven't had rain or snow for quite some time. may be heading the way of a drought if that doesn't change soon.

winds are still blowing and i still have stuff to assemble in the workshop. hope to hear your bungee cord arrived soon.

[stuart]

dang it! i was stirring spaghetti sauce and went down to the workshop...p/u the parkjet and checked the motor mount for strength. if i had run this pc of mount it would have broken in flight.it moved the angle of down thrust with so lil effort that i decided to try a little test of the movement,and it became like butter with a simple touch. if it didn't break in flight ,it would surely have bit someone.

i installed the one plastic stick mount i had left in the stock drawer and will be using the angle bracket method for pkj#3. any further repairs to the motor mount on pkj#2 will require replacing some foam.... i may try bending light alum strip metal i have left over from making a lg for the slick to make a light ,but strong mount.I'll use the dremal to round off the sharp edges.

for now i just want to get it in the air with the v3 and see how fast she'll go.

[stuart]

pictures of the final product before the next attempt to launch.

it's a very filled canopy and the location of the battery needs pushing back to attain cgwhich is great since i do have room for that. the plastic motor mount is way more solid than that cheap alum one, and the esc is level and zip tied down,

53 amp at wot bench test is ok for the 60 amp plush esc. 770 watts,i can't wait to be in the air!! i also hope to be starting pkj #3 soon as 1&2 are so beat up.

[solentlife]

Hey Stu ... the battery needing to go way back is the problem I have. The V3 + Rx is enough up in the nose to really tip the moment fwd ... takes a lot to correct. What we need are short dumpy LiPo's .... not long slim ones. That way we can get weight more concentrated.

I'm thinking to relocte my Rx ... as in the nose I need servo extension leads.

The metal bracket DIY .... from now on - I will use that on any future PKJ ... for less the 20 cents a bracket and 20 mins work to drill ... 10 mins to fit ... done deal !

The HK Alloy mount initially looked great and was nice design ... pity the metal is not up to standard of design. In my view - too much emphasis on alloy and light weight than a good strong mount.

This week weather looks e ... this is driving me nuts !!

[solentlife]

So Bungee arrived ... 10m ...

Doubled over, joined to lines.

Measured at :

5.30m Bungee
4m line to model / anchor line joint
2m to model ring from joint
3m to anchor release from joint.

Stretched to 5kg pull ........... 27m overall ! Means 27 - 4 - 3 = 20m ... - ~4x stretch of the bungee.
To set-up I carry a fishermans digital scale.

I set-up with normal metal guy stakes thinking they would pull out ...... no they held. I will use 3 in a triangle for main bungee anchor... 1 through bungee loop, other 2 via light line out at V to anchor the 1st stake.
The release stake is not so good and needs sorting as the Youtube vid of a tent stake in our soft sandy ground isn't so good.

I have an old 2ch Supermarket model that just sits around .. so that was put on the ramp and used as a test model. Wind was strong and it kept blowing of the ramp. Finally I got a launch ......... WOW !! amazing ...... but model did a loop overhead and ended up in a tree. (I got it dowqn later).

So verdict ? I reckon good to launch PKJ and my EDF ...

But I need to sort a better release than standing on the loop as the video shows. Or get a better stake to hold ready for foot release.