Dale's Typhoon Thread #2

Dale's Typhoon Thread #2

Postby Dale » Tue Feb 05, 2013 3:07 pm

For those that didn't see it, back on the original MFNZ forum I had a 62" Hawker Typhoon (Tony Nijhuis RCM&E plan) on the go.
Hopefully this thread will return one day, but in the meantime i thought i'd update.

As we left it circa a year ago, it was all doom and gloom, overweight and looking dicey if it would fly. (It still hasn't if you are wondering). Had a few jobs to go, and it got put in storage while i moved house, took an overseas holiday etc.

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Re: Dale's Typhoon Thread #2

Postby Dale » Sun Mar 17, 2013 3:49 pm

Well, recently a burst of enthusiasm came back, and i thought i'd finish it, even if it doesn't fly, at least it's finished and not hanging around getting in the way.

The first thing i did was the cannon. (in the above pic they are blu-tak'd on for show)
These consist of two pieces, the main cannon and a short threaded section which is embedded into the wing leading edge, with a nylon bolt screwing the two together.

Set the bits up in a jig, then glued the fixed part in, and faired and blended, then painted them. A very slight tweak of one wing top surface camo and they are all on the grey part of the pattern.
(yes, this should all be done prior to final painting the first time around!) - I only had to repaint up to the first (tape) panel line, so wasn't too much going over old ground.
IMG_20130127_180413.jpg
cannon attachment going on

IMG_20130128_124728.jpg
ready for top coating

The cannon themselves were painted top coat grey all over, (+ black muzzle), so no worries about orienteering top and bottom camo etc. (as they screw on that's just too much effort).
Pretty happy with final result.
IMG_20130205_183126.jpg
final result


Still not quite over how big they are, they look awesome! Cheers again Alex.
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Re: Dale's Typhoon Thread #2

Postby Dale » Sun Mar 17, 2013 4:47 pm

Nek bit was the gear doors.
Threw some glass over a bit of 2.5mm balsa sheet to toughen it up a bit, then cut them to suit the over gear wells, with about 3mm overlap. They sit proud, as getting flush fitting is beyond my skills at this point. (And sounds like an excuse for more weight!)
Not completely scale, as the real deal covers more of the wheel, but i shortened them up a bit to get a bit more grass clearance. Fullsize also has inner doors, but that's something that won't be happening here. Similarly, the actual retract mechanisim remains visible, but that's fine with me.
Squirted some paint over it (grey underside and a bit of white stripe), and green interior.
Small plastic standoffs get it at the right height, and i drilled and tapped the sides of the HK struts. 3mm nylon bolts hold the doors to the strut. Hopefully in event of a damage-producing event, either the easily replaced doors, or the nylon bolt, will give way without major drama.
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For those who missed it, the retracts are the Eflite 60-120° electronic units, and seem bloody good. Thick and chunky in the right places, and haven't as much coughed in the wrong place in dozens of cycles while i been playing with here.
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Re: Dale's Typhoon Thread #2

Postby Dale » Fri Mar 22, 2013 4:40 pm

Next part of the dealings was the power system.
This goes hand in hand with the overall weight, and the cg.

I had originally intended (hoped? dreamed?) of 6S 5000, but this meant the batt would be in the fuse above the wing, and thus add a stack of weight without doing anything for the hugely aft cg that this machine has.
The prototype flew on 4S, (and weighed 3.2kg). I recall (without checking) that it used 3300, and had a pair of them in the cowl, one being ballast.

I came full circle, and have ended up with 5S 4000, and low and behold located in the cowl! After thinking I had no room in there for batts.
I've got a 2S on one side, and a 3S on the other series together. Just scraped in, after minor mods to the inside of the cowl. Attached to the sides of the motor mount cage.

Due to the way things are, the batts are pretty much in there permanently, except for "maintenance" as to get them out involves pulling off the spinner, prop and cowl. Easy to connect them to the esc via the gaping hole in the front of the cowl that all Typhoons come factory fitted with though!

Below and behind the motor is the 80A esc, and Castle Creations BEC.

Some space is available below this, between batteries, to mount lead required to the firewall. Weight of lead required:TBA
Good news is it definately feels better via the "finger cg test", but yet to go back to there.

My radio is FrSky, which has telemetry, although i haven't really used it. If ever there was a project to figure it out, this would be it, so i have motor batt voltage sensor, and a current sensor connected up.

Both of these talk directly to the Rx, which transmits the data (along with Rx voltage) back to my LCD screen mounted on my Tx. Once i get it sorted, i will be able to see both motor and rx voltage, batt current, mAh taken from the batt, and watts consumed. (At time of writing, voltages working, haven't figured out the current sensor yet).

IMG_20130322_172553.jpg
a crowded engine bay!

IMG_20130322_172533.jpg


Next step might have to be some exhausts.
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Re: Dale's Typhoon Thread #2

Postby DH100 » Fri Mar 22, 2013 7:52 pm

Hi Dale

How much flight time do you expect from this set up?

The E-flite retracts seem to work well.

Cheers ... Brian
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Re: Dale's Typhoon Thread #2

Postby Dale » Sat Mar 23, 2013 6:35 am

Around 4:30 is the number from Motocalc. This is the main reason for the telemetry hardware i've put onboard.
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Re: Dale's Typhoon Thread #2

Postby Dale » Wed Sep 04, 2013 7:59 pm

Well, having spent the weekend at the Forsyth Field and Float, during which i had the pleasure of watching a pair of Typhoons (bigger than mine) flying awesome.
Bolstered by that, and the success of my Harvard, this one has jumped back onto the workbench.
Weight and/or CG was the main issue, needing circa 500g of nose weight to balance last time i looked.
I knew that I had been a bit heavy with the paint, (hardware store enamel spray cans) and of course any excess weight down aft needs to be offset by about 5x up front, so i spent 24 hours contemplating this.
As a related matter, i wasn't happy with the roundels/markings (note the blue in the previous pics being removed), and i had even clearcoated over the whole thing to seal these down, which obviously didn't do anything, so there was a now pointless clearcoat over everything.
I decided to paint strip one part and see what difference i could make if i was to repaint the whole plane.
The right outer wing panel was the part to volunteer its services, so cleared the bench and got to work.
The easiest (if not the cheapest) was to pretty much drown it in Acetone and get busy with a steelo.
About an hours scrubbing, and a touchup where needed with sandpaper, had it back to the fibreglass.
The difference? 54g! Or in other words, painted = 329g, stripped 275g, or 22% of the final weight. Note this also includes a good amount of the high-build filler though.
So I wonder if i can get it repainted for 20g or so next time around. Unless i find out otherwise, i'll repaint with acrylic this time, and will be applied by spraygun.
One wonders what difference this effort will make to the overall plane weight/cg once done.
DSC06114.JPG
Not mine! Alex Hewson's magnificent 50cc machine.
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Re: Dale's Typhoon Thread #2

Postby Dale » Wed Oct 02, 2013 5:31 pm

Based on the above results, I decided to strip the entire wing and repaint.
If this then turned out worthwhile, I would then look at repeating the effort with the fuse.
Thus after de-installing the servos, retracts etc, i paint stripped the entire wing. Frostbite threatened after 2 hours of hands immersed in acetone. The things we plane geeks do! I was seriously amazed at the amount of paint on the wing. For some reason I had coated the entire lower surface in a base coat of white, which proved to be the hardest colour to remove. I guess it has extra "stuff" in it to make it non-opaque. (It seemed like a good idea at the time...?)
Stripping was then left to dry for 48 hours, then re-prime, less is more this time. No one can see the glass weave at 20 paces during a flypast so didn't go to the same extent i did last time.
Reapplied the panel lines (Repco 3mm pinstripe tape), and then started repaint.
This time i went to my new friends at Car Colours (Albany), who mixed me up some "acrylic" in matched colours to the existing. I don't intend on repainting fiddly bits like the gear doors and cowl, and was quite happy with the previous colours so it is just a straight one-for-one repaint as it was. (I say "acrylic" because thats what i was after, but these paints don't thin with, or clean up in water, which is my definition of "acrylic".) It should be obvious by this time that i am a rank amateur at all things paint related, but its proving to be fun and good education.
Repainting this time is being done by thinning the paint with two-way thinners and sprayed via a touch-up gun.
So as of now, I have repainted the bottom of the wing, being the primer, panel lines, grey underside, and D-Day stripes. Nothing at all yet on top, which will happen in next few days.
And for comparison, the previously mentioned right wing panel, at 275g stripped, is now sitting (i.e. including bottom repainted) is sitting at 280g. So we are on track for a huge weight saving here! Am keeping a close record of the weights of the wing, can't wait to see where things end up. The learning curve continues.
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20131002_174136.jpg
Wing underside repainted. (one outer wing panel is right side up, showing panel lines.)
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Re: Dale's Typhoon Thread #2

Postby Dale » Tue Oct 15, 2013 6:32 pm

Wing is repainted.
DSC06279.JPG

Spraying acrylics is hard! As mentioned earlier, i'm pretty amature at this, so it's been a steep learning curve.

The order i did it was:
grey all over underside (only once-over where invasion stripes are)
mask off grey then white invasion stripe block
mask off and black invasion stripes
mask off entire bottom then dark grey over all upper side
mask off then green pattern
unmask all, and remask for and spray the black walk area on centre section
brush the interior green on the wheel bays and wing joiner ribs.

The black was by far the hardest to paint, it just seemed to suffer all sorts of issues, such as not drying evenly, or being most intolerant of not being thinned correctly. Perseverance paid off, got it sorted though. The dark grey was next most painful. I guess idiot proof spray cans have stuff in them to make them easy to use! Acrylics dry quick though, without the solvent odour, so was good from that angle. I don't have a workshop i can spray in, so it's only when the weather will let me.

So the big question?

Our right wing sample:
Previously Painted: 329g
Repainted: 283g
Thus a difference of 46g! (Note this does not include the hinges though)

Left wing is 37g less, and centre section is 35g less.

So overall the weight loss on the wing is approx 118g, or have taken 6.8% from the original ready-to-fly wing. I haven't been as much of a perfectionist this time around, as being able to fly is now more important than a great looking hangar queen! (Note all meaurements taken on the el cheapo $20 digital kitchen used and abused kitchen scales, so who knows how accurate these numbers are).

I have since reassembled the centre section, (i.e. put the retracts back in) and am now working on the outers, putting in the servos and rehinging the ailerons. Should have this all back together in the next week.

So it's a given that the fuse will now get the same treatment. Imagine if the back end gets 30g lighter, where that will extrapolate out to in terms of lead from the nose...
As part of that, i will likely make a new built-up rudder, and cover with solartex, so should be lighter, and look more like fabric. (The drowing in acteone process dissolved whatever glue it was i stuck the hinges in with, probably CA). Unfortunately, this might be some time away, a house move is on the near horizon.
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Re: Dale's Typhoon Thread #2

Postby runfrcover » Tue Oct 15, 2013 7:11 pm

That is good weight savings! definitely worth the effort
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