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Nov 14, 2012, 06:04 PM
looking up, down under
scruffy1's Avatar
Originally Posted by Xmod
33years ago i used to fly control line at a club on the Central Coast of NSW, you bought back some memories by saying that
I dont have a y harness for the batteries, ill have to make a Pitt (sic) stop to swap them over. I have only been back in the hobby six months and have very little idea what i am doing. Im going to take the pitts, and the wing, around to an old hand at this before any maiden. Ill let you know how it turns out
we're in the same situation

i flew control line in the mid 70's, after initially building simple kites at ~age 10, then small self designed gliders

i moved on to peanut scale and larger free flight gliders, and then built a drifter 2 which saw me then segue to a series of scratch built gliders loosely based on the flinger (a very early r/c handlaunch glider - back when javelin launch was the go)

i sorta dropped out between parenthood and other distractions (overclocking computers from early amd socket a, through 939, and then jumped to the dark side with the core2duo series) - in fact i had a break from the pitts because i found a quad core processor in a "dead" computer at the very recent council e-waste pickup here, and have upgraded my desktop for free - a yorkfield q8400 that is rated for 2.66ghz that is happily humming along as i type this at 3.33ghz on stock volts
i can sell the dual core e8400 it replaced for enough to buy another aeroplane

but i digress...

i got into electric a few years back with a slow V; that inspired me to buy a lipo for it and then i needed a charger, so i had the basics - as a trainer it was only so-so, and had a brushed motor, but i could feel the potential for electric at the local park, only a short walk down the hill

i was vacillating about getting a radian pro, and bought the spektrum dx8 in anticipation, but the radians were out of stock, so i bought a hobbyzone champ as an interim measure

the best toy ! i very quickly got more proficient, and still love it

that was only about a year ago.. and then i discovered hobbyking and started a shopping spree

since then i have had the mini-stick (amazing fun!), the bonsai - same! and have a canary and the binary 900 pending me getting onto the projects; the pitts is close to finished, and i have a cuckoo that is almost done too

there's also all the carbon and glues and various electrical gizmos; there's a huge stash of orangeRx receivers and servos and lipos; i can scratch build with my remaining balsa from last century, and i am seriously considering importing a big stash of depron from usa, plus sourcing some contest grade balsa and jap tissue locally
god bless the interweb !

my blog tells the story of my obsession returning - sadly i killed the spitfire (beautiful, but not a clever choice for the park, as it is relatively fast, and weighs enough to injure people)

the pitts will be a great addition to the line up, and other than my gliders is the most dangerous member of the squadron but still thankfully pretty benign

whew! time for breakfast. then back to building

hope the flying is good for you
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Nov 15, 2012, 04:19 PM
Proud of Brushless Sprouts
Commander Clumsy's Avatar
Originally Posted by scruffy1
that was only about a year ago.. and then i discovered hobbyking and started a shopping spree
god bless the interweb !
More or less the same story here, only a few years earlier, and some years younger... curses to you, HobbyKing!
Nov 16, 2012, 05:35 AM
looking up, down under
scruffy1's Avatar
Originally Posted by Xmod
Right.....finished. With both batteries.........590g
Plus some decent wheels and the bracing is one size up as well
must have had an error on the scales here with my first reading i think

i stacked everything and the kitchen sink (actually i left off the kitchen sink) and totalled 520gm with one only 1300mah lipo included

the bolts for the horns are still somewhere in transit, so i took the horns back to the supplier and ended up with m2x20mm instead which are fine for the task

the ailerons with a servo each are amazingly mobile at full throw even on the outermost hole on the control surface horn - photos tomorrow in better light

not much work to go till it's done, but i tend to drag out the process as demonstrated
still wondering if the battery will need to go further forward than i thought in light of your balance issue

how'd your test flights do, xmod ?

late edit : just re-programmed the orangeRx r610 with flaperons rather than simple full house, just because i could, and really because i wanted to see what it can do in that mode

oh boy ! i can not only mix flaps for low speed and landing, but i can also reverse them to couple with the elevator, just like the bad old days of flying my flite-streak on wires

i have a feeling that once i am confident with basic controls i can go way silly with the dx8 look out !
Last edited by scruffy1; Nov 16, 2012 at 07:45 AM.
Nov 17, 2012, 04:32 AM
looking up, down under
scruffy1's Avatar

almost there

back into it today; the weather here has been windy and then pouring, but moderated enough this arvo to take the bonsai out for another sortie after the building - i still need to get the cross rigging and aileron links organised

i couldn't resist fitting a satellite receiver - i have a spare, and i though "why not?"just because i could... initially it was going to go in obove and behind the wing, but then i realised it was way easier to gouge a thin receptacle and slice a slot for the aerial to run along (as per the photo) so the two aerials are essentially at 90 for best reception... equally, it means i have glowing bits in the fuselage in two spots because i can

i put a depron "roof" on the area, and sealed the top of the aerial slot, so there wasn't going to be a mess of glue in there when i added the wing

i gouged a bit more space to feed up the wiring with the aileron cables, and then dug a further hole behind the servo to stash all the excess from the other wires; the aileron leads were just long enough, as i had used the distance available to space the sevos in the wing as far as possible, but the rudder / elevator / throttle (and satellite) has a dross to spare

it all worked out tidily enough, as you can see

the canopy sits perfectly over the top and hides everything while still allowing the ruder and elevator to work without hitting anything, although the elevator won't run full range without binding, but still has deflection aplenty... if i decide it needs some help i can couple the flaps like a control liner - and i am curious how that would be in the air

epoxied the top wing after fitting the aileron link mounts under all the ailerons with epoxy as well, lining them up with the aileron horn for maximal transmission of the control movements i hope... dunno if the ailerons will need stiffening, but the available throw looks like it is severe overkill., and i have the radio programmed for 2 stage flaps which i will activate once i get too sure of myself and likely discover i am not that competent with 5 channels, although i am now getting pretty confident with full house

i added a skid that looks way slicker than the sad half moon they supplied - the parts will be recycled as motor mounts for something small i expect
final details were some black dvd marker to complete the colour scheme on the struts and bottom of the bottom wing where there is a gap, and whipped out the yellow marker for the same reason under the lower wing

if i'm going to be obsessive then why shouldn't i go the whole way ?

the last few shots show the receivers lit up when it's on

work again tomorrow and into midweek, but thereafter i am hopefully good to go if the weather holds out, and i can convince myself to cut a hole for the battery - it looks too cute and streamlined to whack another hole into
Last edited by scruffy1; Nov 17, 2012 at 05:31 AM.
Nov 21, 2012, 05:28 AM
looking up, down under
scruffy1's Avatar
finally some more spare time, and the weather has gone all windy

ah well...

i used the supplied fibreglass rods for the cross bracing, using the holes in the struts as the positioning; the fuselage to top wing one went in first, which i aimed for the wing / fuselage intersection at a point 6cm behind the back of the undercarriage reinforcement

using that as the guide of the other bracing brings it to hit the top wing just in front of the rear of the baldachin, which rakes it forwards like the struts, and suits my aesthetic sensibilities

i'd like to take it out in the calm (when there is some) with the battery simply velcroed in the place i reckon it belongs, to confirm the trim is close to perfect before i cut a recess for the final resting place; weighs in at just shy of 520gm fully loaded (sans velcro)

still waiting to hear the outcome of xmod's pathfinding missions
Nov 22, 2012, 07:11 AM
Registered User
Sorry Scruffy, up here its either been blowing or raining or I've been working.
With the two 1000mah batteries i am balancing at 15mm or so behind the lower wing edge. How can you balance there with one??????
As a side issue, can we buy sheets of epp foam in Oz? I have been having a look at the F22 profile models with the mid engine mount . Cut my own and i already have the spare hardware! Sounds brilliant.
Nov 22, 2012, 07:22 AM
Registered User
They are some funky looking wheels you have, very un control line
Nov 22, 2012, 08:15 AM
looking up, down under
scruffy1's Avatar
Originally Posted by Xmod
They are some funky looking wheels you have, very un control line
you can thank the now dead hobbyking spitfire for being the wheel donor

i don't have a local source for epp (yet), but if you find one let me know because i am very definitely interested

strikes me i might have to ship in a big batch of mixed depron from here and i just noted that they do epp too, so that might be part of an even bigger stash as my christmas present to me

as for balance, i am packing a 1300mah turnigy 1.3 into the hole shown in the photo, which adds an alleged 115gm (actually ~113 on my scales) bringing the loaded weight to 515gm
Nov 22, 2012, 03:54 PM
Registered User
Hi Scruff,
Wow the land of the free and the home of the cheap foam! Thate six EPP F22s for $70 us. Did amyone say combat?
australian Epp

Ok sorry for the hijack,
Did you have a test fly with the batteries strapped on before you cut? The Turnigy nano tech 1400mah 3s i bought for the plane has been pinched for the wing. I really need to get the Pitts in the air to sort out what i am goong to do with the battery. I bought a 50 pack of # 1 lead weights from BCF but am reluctant to add weight, even to fix CoG issues. This weekend should be interesting
Nov 22, 2012, 04:45 PM
looking up, down under
scruffy1's Avatar
Originally Posted by Xmod
Did you have a test fly with the batteries strapped on before you cut?

but i have put an ounce of lead under the lipo to be decidedly nose heavy for the test flight, and the batteries are almost done and the wind speed is <5 knots

i also have a 9 gram weight as the next step down, and if it looks good then i'll go "naked" for the third battery

news here within the hour...
Nov 22, 2012, 07:27 PM
looking up, down under
scruffy1's Avatar
well, a short sortie and a few lessons... but no catastrophes so it's all good

for reasons unknown the right aileron which had been trimmed with a lot of "left" to zero it seems to have rediscovered its neutral point and needed to be re-trimmed to near zero on the sub-trim

i compensated for that with the normal aileron trim, which probably added to the "zoom" by effectively adding the equivalent of a degree or two of flaps. because even with an ounce of lead it needed some down trim

on the plus side it cruises at about walking speed at half throttle, but isn't quite "unlimited vertical" at full throttle, which will likely change if i bump the prop up an inch - will check the current if i own that option later today and report back here

turns with ailerons definitely benefit from rudder, which has huge authority - getting the spitfire to stall turn was always somewhat hit and miss whereas this turns 180 instantly in any climbing attitude ; even did a tiny bit of knife edge, which i had never attempted successfully before

the counsel of flypaper2 in this post finally made more sense; i couldn't see why the landing gear mount would be a weak spot but on the very first "arrival" i was less than gentle, and on the next flight the undercarriage jettisoned like i was a messerschmitt 163
that increased the climbing tendency no doubt, but luckily i had already thrown in the extra 9 gms for good measure

on landing (which i did remarkably gently - into the wind, cut the motor and stall about 6" off the grass, and plop! ) i realised that the ply had split in an obvious plane vertically so the mount could open like jaws
this will be glued and i like the idea of some fibreglass on each side and across the gap underneath - fly's idea of a ply triangle is sensible, but the aesthetics of his solution is against my design brief of beautiful toy

not until i walked home that i noticed the left aileron linkage rod had vacated - the nut holding the metal fitting to the plastic on the bottom aileron link had obviously come undone, and the top aileron was free of any control... easy to replace, as i have some spares from the original aileron linkages given i used the spitfire fittings

there's some blue thread locker in transit in my pending order, but i might just add a drop of either epoxy or cyanoacrylate as an interim measure, because rogue ailerons might be problematic - seemed to land okay anyway

six minutes of erratic flight left me with 11.27v and took 417mah to charge up to 50% in the 1300mah - comparing to the spittie seems that 6 minutes w.o.t. would be a "safe" flight time leaving 20% residual, but more research required

and of course meantime, wind speed has kicked to > 10 knots, and this plane looks like a still air specialist

short summary :
  • add noseweight and then back off if it seems a good idea; it won't balance with the 1300mah in the available nose length - an extra ounce is a reasonable first guess
  • reinforce the landing gear mount - minimally i would suggest epoxy in the slot
  • lock the linkages with something, or re-check them frequently
Nov 23, 2012, 06:10 AM
looking up, down under
scruffy1's Avatar
i fixed all the details listed that were minor irritations really

chose to fill the gap in the undercarriage mount with 5 minute epoxy and microballoons - light, flexible and strong, so we'll see how that works out; and i cyano'd the aileron connector nuts

flashed the firmware in the dx8 for good measure and programmed the esc which kept losing the throttle settings - my mistake as i hadn't done it quite right first time round, and now it is faultless

reset the throttle curve to sit at ~50% from 25-75%

i suspect the ailerons either need differential or some mixed in rudder, but haven't got any coherent clues about that yet

i'll see how much nose weight it can do without by and by if the weather co-operates; failing the ability to dispense with the 30gm of ballast i am looking at the 1500mah sibling of my current lipo, which apart from length is very close in dimensions, and conveniently adds 200mah for 30gm difference - if i have to carry 30gm to trim the balance, it may as well pay for the ride with added duration
Nov 23, 2012, 05:50 PM
looking up, down under
scruffy1's Avatar
woke up early to blessed calm and clouds lit from below by the sunrise

by the time i'd scoffed a banana and had a coffee the sun had risen above the overcast and the batteries had been topped up to full, the stig had donned his lucky helmet, and we were all systems go...

perfect ! still air and minimal glare

down the hill i limped (dropped the vtr250 on my left leg on thursday, still got huge grazes and some bruises as well) with the machine

what a great toy ! didn't help i had the elevator throw reversed, but could have been worse - my rotation for take off became a nose-over (teach me to reflash the radio and not double check the servo directions ) - easy fix with the dx8 and then tally ho !

3 batteries later i am home and smiling
the sun is now well up and the nor' easter is picking up as i type; that'll give me a chance to epoxy the rigging braces where they cross, as the left one is again loose - don't know if it matters at all, but the cyanoacrylate is too brittle for that task

despite a few bumps on landing, filling the undercarriage slot with epoxy and 'balloons has been great as reinforcement with just the right amount of tolerance to the vicissitudes of challenging arrivals

the final flight i dropped the nose weight to 29 grams from the 32 grams (ooh ! brave !) and it flew well, but unsurprisingly needed more down trim - the photos show the details
i suspect that with practice the nose weight can go lower, but it is already very responsive, and the extra cargo appears inconsequential so i will ease the cg rearward with maybe 20 grams as the next step, then 10 if i don't freak myself out

flight notes from today :
  • leave the control at full rates with all available throw and tease the sticks gently with room to spare for violent manoeuvres; wind the rates down for landing and take off as required - i have dialled in expos of 20/rudder, 30/elevator and 35/ailerons - no mixing, no other trickery; the throttle is set to 25%=40, 50%=50, 75% =60, and zero and 100% left alone, with expo actuated - makes it easy to keep the throttle comfortably near the neutral position
  • the rudder is very effective - managed more knife edge, and almost can do a knife edge loop (need lots more practice, obviously )
  • bank and yank won't do it - you need to utilise rudder for co-ordinated turns - this will be a great learning experience for my piloting technique
  • it will fly at so slow a pace i am surprised it doesn't stall - but it just floats and floats
  • full power will go vertical but not endlessly - probably doable with a bigger prop, which i will need to order
  • heaving the sticks to full throw at altitude makes for impressive freestyle stunts; recovery is concise and immediate
  • with throttle at cruise / full ~ 50/50 i get an easy 7 minutes out of the 1300mah, with 11.1v residual on the lowest of the 3 batteries after doing 2 "go arounds" due to excited golden retrievers on the approach - that flight was probably 8 minutes total, so room to move really, especially with a bigger battery for ballast

probably a little flitty for a beginner, but if you can fly ailerons confidently, this biplane is highly recommended !
Nov 24, 2012, 01:46 AM
Registered User
Up for the maiden flight of both Pitts and the wing at 5.30, otherwise the winds pick up pretty soon after that.
The pitts, even with two 1000mah 3s batteris flew like there was a brick tied to the tail. Added nearly 80grams of lead and it was still unstable and I got it down in one piece, minus a prop.
Have a look at the photo, It is balancing at 15mm from front of lower wing with a 2200mah 3s battery!!!!!
ok. flight times should be good, but this little porker now had 615g AUW.
The plane is dead stock and built to the guidebook. Any ideas???
Nov 24, 2012, 02:04 AM
Registered User
Almost forgot, yes the ply landing gear support promptly fell out, only 3 drops of ca holding it in looks like. Considering one of the landings was really more of a slo-mo cartwheel the plane is very resiliant.. The wing flew..... Suspect it maybe is faster and a lot more agile than i am....how do you keep track of a sky blue wing scruffy? Mine is orange and i had to guess up from down a few times

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