Nice. I think I'll have to copy your canopy lines

Originally Posted by headlessagain

Thanks. I used £1 store foam brushes for the larger areas/base coats and it was all painted free hand.
http://www.ebay.co.uk/itm/12PC-Foam-...item2c67d5581f
I did goggle "warbird camo" or something similar to get some ideas. The paint was acrylic craft paint for the top and emulsion tester pot for the underneath.Two coats were required. The decals were bought online from Ebay.
Andy

Was any prep work necessary to aid the paint adhering to the foam?
How well is the paint holding up?

I was intending to use cheap acrylics thinned down using windex sprayed through an airbrush

I used Multiplex elapor primer. You apply it and then wipe it all off again. It's main purpose is to remove any mold release agent which would inhibit good paint adhesion
Still have to maiden the finished plane so the jury is still out on durability
Andy

Originally Posted by headlessagain

I used Multiplex elapor primer. You apply it and then wipe it all off again. It's main purpose is to remove any mold release agent which would inhibit good paint adhesion
Still have to maiden the finished plane so the jury is still out on durability
Andy

We have no chance of getting the primer through our multiplex dealer.

You could try some Isopropyl alcohol on an unimportant area to ensure it doesn't melt the foam. It's it's safe, than give the whole airframe a wipe over and then remove as much as possible with a clean cloth. Let any remaining evaporate and when dry you should be ok to paint.
I might try some to clean to glue from my canopy.
Let us know if this works
Andy

Originally Posted by headlessagain

You could try some Isopropyl alcohol on an unimportant area to ensure it doesn't melt the foam. It's it's safe, than give the whole airframe a wipe over and then remove as much as possible with a clean cloth. Let any remaining evaporate and when dry you should be ok to paint.
I might try some to clean to glue from my canopy.
Let us know if this works
Andy

Yeah I got small bottle of Isopropyl Alcohol a couple of years back from the local hardware shop, gee it was expensive and didn't go far, so I ordered a bigger bottle through the local chemist, and that cost over $30 and that bottle wasn't that big.

Originally Posted by aeromaniac

Yeah I got small bottle of Isopropyl Alcohol a couple of years back from the local hardware shop, gee it was expensive and didn't go far, so I ordered a bigger bottle through the local chemist, and that cost over $30 and that bottle wasn't that big.

I have about 5 litres of it at home ... it's used in Compasses as the fluid. I'm lucky that I own a Petrochemical Laboratory - so I just added my need to lab orders. But yes it's not cheap via retail outlets.

Nigel

To be honest - I never bothered to 'wash' my 2 PKJ's before painting ... just gave them a dry-cloth wipe.

No indications of any problems.

Nigel

Having had trouble finding way to mount my twin motors to the PKJ ... I've given in and bought HK beam mount gear x2 ...

As originally intended - I shall cut away a section low down of the tail fins at rear ... insert the wood beams and motors recessed into fins. The motors I plan to have about 30 - 40% back into fin line.... to keep props as close to body as reasonable.

I have 2 x 50A opto ESC's so will power Rx from a 250mAh small Rx pack I have. This means then that the power supply will be independent of other demands.

The motor weight will allow me to have decent sized LiPo up front ... I may even go 4S if the model survives 3S trials. Yes - I'm totally mad ! I have thought of twin battery set-up in fact ! Yes not just mad but totally INSANE !

Once I get the desired speed ... I'm looking for 275kph ... I will then reduce the power and create a reasonable speed machine having done the biz. The actual specs / work will be detailed here and on the Need For Speed thread on Wattflyer that actually spurred on this development.

For those new to this concept. The PKJ is known by many who have one - to suffer immense torque problems with high power set-ups. My idea is to mount counter rotating props via a twin motor set-up. This should in theory result in near zero nett torque. The having two props as well should increase nett thrust, even though gross thrust is similar to a single prop set-up.
The problem will of course be :

Catapult launcher rails co-incide with prop arcs .. so launch will be engines stopped ...
Amps draw is doubled so run-time will be very short
Weight of installation will mean a heavy model and high air-speed to maintain glide ... FAST landings !!
Stress on the longitudinal centre-line where we already know the PKJ is weak ... take a PKJ and move wing-tips and you see the centre flexing .. (I advise people to fit the wood beam in the motor slot to aid strengthening).



Just an 'sketch' version I knocked up to view the idea ...

Nigel

"Yes - I'm totally mad !" Yes, but in a good, sort of, mad scientist way
Will watch with interest (from a safe distance)
Andy

Originally Posted by headlessagain

"Yes - I'm totally mad !" Yes, but in a good, sort of, mad scientist way
Will watch with interest (from a safe distance)
Andy

You're not only one standing well back .... most of who I fly with when I get my PKJ's etc. out step back a bit !

They think I'm a right loony.

Well - I don't care ... people said bombs cannot bounce on water - but they were proved wrong !

It will take extreme care in setting up, the positioning of ESC's ... etc, will be biggest hurdle I think. I hope I can put them each side just inside front of fins, help with balance.

I may fill in the centre motor slot with pink foam to add some body and strength but no weight ... maybe ... haven't decided yet. I was going to leave the centre beam if wanted to return to single motor ...... but I'll need to cut into that area to remove the DIY metal motor mount I have.

I hope to be home soon and once postman delivers the last few bits I need ....... I shall post up the work.

Nigel

well after i read the whole thread, i build my parkjet, with the hk suggested power train to get 100mph.

Needless to say it is a handful - coming from a guy whose previous and only other plane is a Bixler... I've flown 3D heli and stuff, but now im on to fixed wing - kind of a backwards transition from what i hear from many others.

Anyways, what I didn't see on this thread is a suggestion to put an immense amount of expo on this bird... I tried with 15% expo - totally uncontrollable.

Not used to the speed - so i didn't go above a quarter stick, but none the less, a blast.

I had my neighbor launch for me - 3rd time was a charm. I will say that i did not get any torque roll tho running a 4.5 x 4.5 prop.

Bixler to 100 mph Parkjet is quite a leap. Good job at nailing it on the third launch. The Parkjet tracks really well and has no nasty habits but I would always have a low rate with lots of expo for the maiden. Once you are comfortable and at a safe height then switch to high rates (still with expo) and see how you like it. You won't need high rates for WOT runs as the model will be increasingly sensitive to control inputs as the speed increases. Plyon racer style models often use a single narrow aileron for this reason.
Just swapped my motor to a Mystery 3000 kv which I will try on a 4.5 x 4.5 on 3S & 30 amp esc. Might step up to a 4S set up with 4.1 x 4.1 if this works out ok
Andy

Due to return home tomorrow .... and looking at weather.

I'm hoping to have my 4400kv Parkjet in the air this weekend ... having rekindled my drive to push the limits again !

Hopefully I break my own record ... and will try have a video to show ...

Fingers crossed .... anyone for 300kph ?



Nigel

Originally Posted by headlessagain

Bixler to 100 mph Parkjet is quite a leap. Good job at nailing it on the third launch. The Parkjet tracks really well and has no nasty habits but I would always have a low rate with lots of expo for the maiden. Once you are comfortable and at a safe height then switch to high rates (still with expo) and see how you like it. You won't need high rates for WOT runs as the model will be increasingly sensitive to control inputs as the speed increases. Plyon racer style models often use a single narrow aileron for this reason.
Just swapped my motor to a Mystery 3000 kv which I will try on a 4.5 x 4.5 on 3S & 30 amp esc. Might step up to a 4S set up with 4.1 x 4.1 if this works out ok
Andy

I guess it was a big jump. I am used to flying with rudder and aileron, so i am getting used to things. What i notice the most is how much this thing drops on turns - I am finding that you have to accelerate through turns to keep altitude.

I have a starmax p-51 on the way, 1600 mm war bird, I am thinking that it will be easier to fly than the parkjet, maybe a bit more difficult than the bixler, so somewhere in between. What do you think?

In any case, I think the parkjet is more of an adrenalin rush than 3d flying on the 450 heli. Only difference is that a crash will not set you back 50 bucks everytime...