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

[F86-Sabre]

Originally Posted by stuart

ran the final bench test and fine tune the control settings. wattup meter say 205watts,pulling 19amps off a 1300mah 20c 3cell zippy. i still have to do the flight time math,but the first flight will be short so to trim it in the air and check battery power draw. then i'll adjust flight times with strafing flybys at wot.

gotta say,it make me more nervous than other maidens as thi is the smallest,fastest bird sitting on the table.

Awesome colour scheme you've got there! Nice work

[stuart]

$15.00 $13.00
Buy MoreWicked 3000 KV
DonsRC


i so love the hkpj with the wicked jr motor on 3cell1300mah ,using a 30amp esc......possibly getting 70+mph[need radar gun]

I've got another hobbyking parkjet in the mail today.it's on the build table next to the funjet ultra thats also under construction, and plan on boosting this lil bird with the wicked motor shown. a 4.1x4.1 apc,50amp esc ,and a small 1500mah 4cell for extremely short bursts of wot!!and hoping for 2+min flight times.

i plane to mount the motor using a custom designed mount. the motor will be set further forward on the fuse so only the prop clears the Te. i also will trim away the back of the canopy so the esc can be mounted out side the canopy for maximum cooling the same way i mounted the first hkpj I'm flying. the battery will be pushed forward for cg if needed and the Rx will be in between the esc and battery. i am laminating very thin ply wood on the ailerons and also the carbon fiber rods on the te of the ailerons forprep of higher speed flights and will put a strip of hing tape for strengthing the hing line.

just waiting on a delivery from another rc distributer for the esc's. the wattage will be over the top of what the hkpjet can carry but I'm a speed addict now and love experimenting now ,with my addiction,i may need counseling soon...lol.

the color scheme will be the same as the first build so at high speeds I'll be used to the green bottom and orange top...the funjet will also be the green/orange with a sunburst pattern on top done in white.

[stuart]

dhawk,if your still around....how did the radjet work out??? i'm hoping to hear good things about it also.

[dahawk]

Originally Posted by stuart

dhawk,if your still around....how did the radjet work out??? i'm hoping to hear good things about it also.

Hey Stuart,

Had a few projects ahead of the Radjet but it should not take me more than 1/2 hour hour to get er ready for the weekend. If all goes well, should be able to maiden on Saturday or Sunday. Trying to finish up the 6mm scratchbuild F-4 Phantom that I've been building. Man, this is a handful. Experimenting with 2mil colored packing tape for covering. Might have added too much weight. She's strong but a pig. Will be lucky if it gets airborne with the Grayson V-2 -2200kv/30 amp esc and master air screw 6x4E. If she flys , she'll be slow.

Sounds like you're doing well ! I have to give the "King" some credit. Got a delivery on the 24th.

Cheers,

-Hawk

[stuart]

hawk,it took hk 18 days from china to my door!!thats as good as it gets for my orders. soon it'll be the Chinese new year....then all heck breaks loose and shipping suffers....must be nice to party for weeks on end.

i just ordered lipos from hobbypartz for the hkpj,1600mah20c skylipos. i know the setup I'm using will toast these batteries,but i have to keep the weight down or the best speed i get will be a dive toward the ground.

if the parkjet doesn't like the setup on a smaller battery[hope to get several flights off each battery before puffing.

i could always get the radjet...use this motor and esc,along with a 2800mah30c 4cell. if Ron's birds flew 140mph,the radjet should also go pretty good with this setup carrying a heavyer battery.

i took friday off from work,hope to get the funjet maiden during the long weekend. i just never feel rushed to do anything fast anymore. must be old age.

[raad]

i need some advice ..
i've been flying a GWS slow stick for 3 years , and i think its about time to upgrade !

i am looking at the RadJet 800 and the teksumo .. what would be the best plane for me as a second plane !.. both are around the same price range .. but the radjet comes with a motor ! and i got everything else .

i hope to hear replies from the ones who got one of the two or tried them .

[dahawk]

Originally Posted by raad

i need some advice ..
i've been flying a GWS slow stick for 3 years , and i think its about time to upgrade !

i am looking at the RadJet 800 and the teksumo .. what would be the best plane for me as a second plane !.. both are around the same price range .. but the radjet comes with a motor ! and i got everything else .

i hope to hear replies from the ones who got one of the two or tried them .

raad,
I have the radjet but it's still in the box. Why is in still in the box? I bought it because it was irrestibaly inexpensive and fairly high performing ( at least my slow standards). I can only comment on the contents which arrived very well packed from the King and it will go together very easiliy. Been wrapped-up on two scratchbuild foamie ( F4 Phantom & F-15) Stuart above can best comment on recommending the next plane in this category. There are a few Youtube vids out there on the Radjet.

Probably maiden next week weather permitting.

Good luck !

Hawk

[raad]

thanks ,

good luck on your maiden

[stuart]

hello raad,i just got back from flying...10 to15mph winds in the morning ,and to windy for the rest of the afternoon...still hung out to fly the hkpjet....i shouldn't have tried to float in 20mph winds at 0 mistakes high...lol.....now a new motor mount and she'll be just fine to go again.

answer to your question.....don't buy the radjet unless your willing to toss money on the ground and watch it blow away.

there are so many better choices for the money that will improve your flying skills above those the rad jet will teach you. a second plane should have ailerons,rudder,elevator. low or mid wing design and built with plenty of power to pull out of dumb thumb moves like mine today...lol..[i tried to late]. should have a landing gear for those touch and goes....and of coarse,it should be built for aerobatics to give the rush we all long for when flying.

so get the radjet as the cost is affordable,but get a "real" fun plane to improve on and save the jet for those"i gotta go fast" days.

this is just my humble opinion ,learned by lessons that wasted some bucks you shouldn't have to waste.



suggestions on planes....3dhs 41"extra,airfoils yak foamy profile,many foamies to choose and easily repaired. best of luck and hope you find a good second plane!let us know what you choose and how you like it.

[solentlife]

I'm considering a beast of a setup .....

I fly not only fixed wing, Bipes, EDF etc. but also 450 Heli's. I have a 450 heli motor spare .... that with a cutback prop to 5" would likely push the Parkjet to it's limits on a decent 3S pack....

At $15 for a kit ... and most gear I have sitting idle on the bench ..... mmmmmmmmmmmm tempting !!

One comment after reading the thread .... colour schemes. I found that near solid colours schemes even when different colours become dark at distance and difficult to tell. I use broken up schemes ... ie my SM biplane has red tapered flashes across the tops of wings on top of the yellow base covering. The underwings being plain yellow. The difference is easy to see at distance .... even though you cannot determine the colour.

[stuart]

solentlife,the color on the top is solid on my parkjets,and on the bottom wide white strips are perfect . gotta say the orange and green realy stand out in the distance .expessialy when roll rates are a blurr...lol....

sounds like we think the same when it comes to loading these birds for power,i'm starting another parkjet with a wicked 3000kv motor from donsrc[link for his store is in an earlier post here].

here's a few pictures and my design for motor mount will be very easy to build so not to have the motor hanging off the back,it'll be on top of the fuse with the prop clearing the te. the canopy will be cut back to expos the 60amp plush. powered by a bluelipo 1600mah 20c 4cell,using a 4.1x4.1 e prop. if the weight dosn't slow her down....i'm thinking this lil hkpj will be a scream to fly.....gotta love it,addicted to speed!


solentlife...i would be glad to change the title of this thread if you'd do a build of you hkpj here for others to see...the more the merryer.

[solentlife]

My Parkjet is on its way .... had a few $ spare - Don't tell the wife !!

Parkjet + Eagle Tree speed module + Rx switch so I can switch logger on / off via Tx to get true level pass speed ... 5x5E props to go on my 3750KV Heli motor + alloy stick mount.

I think we ought to start a new thread once we get going ...... I'm a long way from what I want ... this is just first days to sort pusher jet and also EDF ..... I have a 5000KV motor, 4S upgrade coming for my 4200KV, 3S stock 50mm EDF ....

Been watching Youtube vids of speed freaks ... sadly the quoted speeds don't hold up when you pass the vid through RCSpeedo .... impressive but mosr are a long way short of what they quote.
Second when they use loggers such as Eagle tree - they forget that max speed will be remembered as it comes out of dive to make the level pass - invalidating the speed. It's why I'm fitting a switch - so I can flick a toggle switch and engage the logger at start of a level run.... switch off at end of run. Land and read the correct speed.

Switch : http://www.ebay.co.uk/itm/Turnigy-re...item3a6ca1f2c9

Logger : http://www.hobbyking.com/hobbycity/s...idProduct=7838

The aim is to generate interest in a speed record for Latvia ... so far I haven't found any info - so it's time to start !! We are also hoping that such activity may spark more newbies into the hobby .....

Speed ? ME ? You bet !

[dahawk]

Originally Posted by solentlife

My Parkjet is on its way .... had a few $ spare - Don't tell the wife !!

Parkjet + Eagle Tree speed module + Rx switch so I can switch logger on / off via Tx to get true level pass speed ... 5x5E props to go on my 3750KV Heli motor + alloy stick mount.

I think we ought to start a new thread once we get going ...... I'm a long way from what I want ... this is just first days to sort pusher jet and also EDF ..... I have a 5000KV motor, 4S upgrade coming for my 4200KV, 3S stock 50mm EDF ....

Been watching Youtube vids of speed freaks ... sadly the quoted speeds don't hold up when you pass the vid through RCSpeedo .... impressive but mosr are a long way short of what they quote.
Second when they use loggers such as Eagle tree - they forget that max speed will be remembered as it comes out of dive to make the level pass - invalidating the speed. It's why I'm fitting a switch - so I can flick a toggle switch and engage the logger at start of a level run.... switch off at end of run. Land and read the correct speed.

Switch : http://www.ebay.co.uk/itm/Turnigy-re...item3a6ca1f2c9

Logger : http://www.hobbyking.com/hobbycity/s...idProduct=7838

The aim is to generate interest in a speed record for Latvia ... so far I haven't found any info - so it's time to start !! We are also hoping that such activity may spark more newbies into the hobby .....

Speed ? ME ? You bet !

Awesome ! I see what you mean about the SpeedoRC doppler versus a real recording device. You've got some real power there. I'm going to give the new stock HK Radjet a go this weekend then determine if I'm ready to handle more speed. The fastest I've seen anything go at our field is 135 mph and it was an eflight Habu edf. Of course, in the US, the AMA limit is 199 mph. Can't begin to imagine what that must be like. Equates to mach 2 something.

Make sure to post a vid when you break the record !

[solentlife]

You can follow how crazy I am on Youtubde .... ID : solentlifeuk ...

[stuart]

solentlife,that speedometer from hk looks very interesting. i read the disscusion and review forum there and still wonder how it's mounted to the plane. it would be interesting to launch the pusherjets with 1/2 to 3/4 throttle fly around mellow until level for a wot speed run....simply don't ever do a wot dive during your flight and only measure the level runs

the parkjet flys great gliding and turns are a snap! you don't have to climb at all,just do large [level]oval patterns ,land and check your top speed.this would negate the need for a switch.

i hope you post you setup as soon as your hkpj arrives,i'll post pictures this weekend of the parkjets assembly with the larger power system....that is if it's not flyable...lol..,it the warmest jan i can remember here in nj.

[solentlife]

i plan to mount the pitot similar to a flight-refule probe on RAF / EU jets .... to stbd and just ahead of pilot location ... so a) it will look scale, b) will have clear air.

the module itself just lies in the fuselage next to Rx ... using a spare channel for power. The switch will be used to g'tee correct run as I like to have some fun as well !! So get her up and settled with a few passes / dives then into serious speed run ...

I have to get my pal to video as well ... so he needs to settle into the follow plane routine. It's not easy as many have found out to keep fast models in vid view !

the Heli motor is rated not only for 450 Trex use but also for 6 - 8" props ... so the 5x5 should not stretch the motor at all ... and later may up to a cut back prop to give me 5x6 ....

[stuart]

got home from work and found time to put together the motor mount,very solid and it may need down thrust added as it looks to be less than the hkpj#1.for now i placed the esc and batteries in the locations to get cg. the smaller battery is a 4cell 1000mah 20c.

i like the looks,and location of the larger battery which is a 4cell 1600mah 20c. this allows the esc to be located very close to the motor and no added length of battery leads required. it also has the rx all the way forward by it's self.

the carbon fiber rods that came with the kit to spar the wings was used for the te of the elevrons[bad spelling...lol]epoxied on as suggested on a thread at rcg forums. thicker cf rods i had on hand went into the wings. I'm still considering adding thin balsa to the elevrons to stiffen them for high speed maneuvers.

funny how i could finish it up in no time but enjoy savoring the build...lol...it will be done this weekend. just a few pictures to keep things interesting......

[dahawk]

Originally Posted by stuart

got home from work and found time to put together the motor mount,very solid and it may need down thrust added as it looks to be less than the hkpj#1.for now i placed the esc and batteries in the locations to get cg. the smaller battery is a 4cell 1000mah 20c.

i like the looks,and location of the larger battery which is a 4cell 1600mah 20c. this allows the esc to be located very close to the motor and no added length of battery leads required. it also has the rx all the way forward by it's self.

the carbon fiber rods that came with the kit to spar the wings was used for the te of the elevrons[bad spelling...lol]epoxied on as suggested on a thread at rcg forums. thicker cf rods i had on hand went into the wings. I'm still considering adding thin balsa to the elevrons to stiffen them for high speed maneuvers.

funny how i could finish it up in no time but enjoy savoring the build...lol...it will be done this weekend. just a few pictures to keep things interesting......

Stuart,

Looks great ! Love the color scheme. Good success with the Sky lipos ? I have a variety of 3 cell batteries and was looking to standardize.

If all goes well today, I'm going to try to maiden the stock Radjet. Might buddy box it first as this is my first attempt at anything that goes over 40 mph. Will also try to maiden my F4B Phantom II scratchbuilt which will be slow, to say the least.

Let us know how she flies !

Best,

Hawk

[solentlife]

I'm moving away from 20C packs .... having found them limiting in my 50mm EDF and not delivering enough punch. They are good packs - Turnigy's and check out fine but as many motors now benefit from a bit more freedom in ampage - I will now stick with 25C as my minimum standard ...

The 20C packs I have will be relegated to my Cessna which is fine on them for general lazing around the sky ... the 25C packs I usually use in her will now be my basics for the PKJ ..

Post still not arrived ! And I'm of on assignment for 3 weeks tomorrow ... so I shall be looking fwd to all the stories / vids of all you lot having fun while I'm slaving away in the desert !

[stuart]

hawk,how did the maiden go with the radjet....i hope all is great and you'll post the upgrades when you do them. as far as those lipos,i haven't tried them yet. I'm pretty much a zippy man but agree to moving up from the 20'c to 30's. it just that i built 2 birds to hold zippies in parralle and a tight fit.

solentlife......i hate the slow boats from china,i also am waiting on some cheap esc's from dealextreem[free shipping and i like some of there na name brand motors.ordered 1st week in dec.......jan 9th they notified me they just shipped everything...never again.

good news is the hkpj#2 is 100% complete!!!!! i plugged in one of my larger 4cell and am in awe of the power. i just have to solder the deans connectors on the pj's batteries and the I'll do a bench test for watts&amps. i may need to research for smaller 4cells as the 4cell 1600mah 20c are about the same size as a 2200mah 20c 3cells[ the 4cells are heavyer]. this is overkill in weight....haveto give it a go as is though and should know soon enough if the hkpj2 is as fast as it sounds..lol. hope to maiden the funjet the same day.

just a few finish pictures. i did laminate the ailerons with very thin sheets of ply and theres no flex as before. i also added a short pc of carbon fiber rod as an extra spar,located it just in front of cg/finger holds. i did this because there seems to be a weak point where the fuse bends very easy. a hard banking turn doing 140mph might snap the pj down the middle front to back. the extra strength at so little weight is worth the add on . i also plan on putting 2 broad white stripes on the bottom wing surface to help with orientation.

heres a few pictures and I'll post the bench test data tomorrow,after that,i wait to maiden.

[dahawk]

Originally Posted by stuart

hawk,how did the maiden go with the radjet....i hope all is great and you'll post the upgrades when you do them. as far as those lipos,i haven't tried them yet. I'm pretty much a zippy man but agree to moving up from the 20'c to 30's. it just that i built 2 birds to hold zippies in parralle and a tight fit.

solentlife......i hate the slow boats from china,i also am waiting on some cheap esc's from dealextreem[free shipping and i like some of there na name brand motors.ordered 1st week in dec.......jan 9th they notified me they just shipped everything...never again.

good news is the hkpj#2 is 100% complete!!!!! i plugged in one of my larger 4cell and am in awe of the power. i just have to solder the deans connectors on the pj's batteries and the I'll do a bench test for watts&amps. i may need to research for smaller 4cells as the 4cell 1600mah 20c are about the same size as a 2200mah 20c 3cells[ the 4cells are heavyer]. this is overkill in weight....haveto give it a go as is though and should know soon enough if the hkpj2 is as fast as it sounds..lol. hope to maiden the funjet the same day.

just a few finish pictures. i did laminate the ailerons with very thin sheets of ply and theres no flex as before. i also added a short pc of carbon fiber rod as an extra spar,located it just in front of cg/finger holds. i did this because there seems to be a weak point where the fuse bends very easy. a hard banking turn doing 140mph might snap the pj down the middle front to back. the extra strength at so little weight is worth the add on . i also plan on putting 2 broad white stripes on the bottom wing surface to help with orientation.

heres a few pictures and I'll post the bench test data tomorrow,after that,i wait to maiden.

Hi Stuart,

Unfortunately, it was a no go on the Radjet Saturday. After a successful maiden on the scratchbuilt F4B Phantom pusher prop( slow as molasses). Under powered so now I'm thinking of throwing a 4C at it.

I went to the table to pre-flight the Radjet. Was really pumped and beaming with confidence. Low and behold the XT60(HK) to EC3 connector adaptor broke and I didn't have a soldering gun with me. Was going to give a go today as it was nice and warm (70F) but the wind was 10-20 gusting to 30.

Looks like next weekend. Holey Moley ! Looks like your souped-up HKPJ is rarin to go. Did you get her airbore this weekend?

-Hawk

[stuart]

yikes.....!!!!!!bench test run this evening using a 1600mah 20c[40c burst] 4cell.

man alive,my hearts pounding from the soundand my dear wifes annoyed i scared her while sleeping in the livingroom...lol......

using a 4.5x4.1 apc prop,these are the stats...

volts in pack for second test run=16.50

watts on 2 second run=793.4wp[this motor belongs in a funjet or radjet]

amps " " " "= 54.20ah...[glad i'm using a 60amp turnigy plush]...........like i said before yikes!!!!!!

so i am now ordering 3 props at 4.1x4.1 as recomended by the seller [donrc]as this is way to much prop[4.5x4.1] ,and i hope to get them soon to retest . maiden will have to wait. i was also shocked by the force of energy pushing my hand forward.....i have to get this bird dopplered or radar gunned on the first flights . on such a small plane and with the extra weight...this is going to be a deadly moving object thru the sky.glad i beefed everything up and might also change the servos out from hxt900's to emax mg micros. i'll do level wot runs only in the beginning but those hard banking turns are what get the blood flowing with the hkpj#1 ,and cheap servos won't make me comfortable around fellow flyers.enough said.
i'm ordering the servos now!better safe than sorry.

[stuart]

emaxs and 4.1 props on order from value hobby.... it's nice to know they'll be here soon.

i post this to say thanks to john for the suggestion i got in a pm,to switch the clevises from plastic to metal.this is why i like posting progress on modifications to the hkpj2 design here at wattflyer.

i did switch out the flimsy pushrods with "real" pushrods.the metal clevise's will also be used with pc's of fuel line slipped on both ends of the pushrod connectors.

thanks again gramps!

stu

[solentlife]

I have a 4200kv motor coming free from my EDF ... and that will be fitted with props on back end of my PKJ .... I have also the 450 Heli motor rated for 6 - 8" props - 3700kv ... so a 5" on it is fine.

The reservation I have is size of the PKJ ... it's very small and will be get lost out of sight VERY quick ! My 50mm EDF is only slightly bigger and that soon gets very small.

So question is ... what size prop can be fitted to a 4200kv ex 50 - 64mm EDF ... can it spin a 5x5 ? If the prop is too much - then I will cut it back in diameter - keeping the pitch. I've cut back quite a few props on various models - using bigger props cut back gives greater resistance to flex and also slightly greater flywheel weight ... It may need the 5" cut back to 4.5 or less.

I'm not really looking for aerobatics - what I want is sheer speed ..... and I have some ideas to try out ... which once trialed - I'll divulge !! Until then it's silly ideas ...

[stuart]

solentlife,why not just order a few props from value hobby? i have a bunch of 5.5's 4.5's 4.75's,and am waiting on two 4.1x4.1 for the parkjet. emp e props.also the emax mg servos.

i would think to large a prop on the parkjet will torque roll it to much. but I'm new to this pusher jet stuff,and hooked on experimenting. lets face it,the 800watts with a 4cell in the park jet is equal to a lead weight with wings....i think it should fly fast...but i better not loose control or someone might get hurt[or worse].