Yet another Ripmax Spit

[kiwi g]

I see your problem.

I guess that the ply engine mount is already hitting the cowl where it sits so a cut and splice is out of the question.

So whats required is something in the line of a piece aluminium bent to two right angles and drilled for motor then slipped inside of mounts and glue and screwed at rear.

   or cut the mount off at rear of motor and reverse mount if possible. but youve probly thought of that.

[Tim Mackey]

Sorted. Your idea of a prop adaptor had me scratching around in the bits box, and sure enough I found an old large adaptor with a 5mm hole with set-screw style fitting, and a long 15mm threaded shaft. Quick bit of turning down in the lathe and shortening, and bingo - one propshaft extension. I simply turned down the threaded "prop" end to the same 5mm diameter as the motor shaft, and the folding prop hub "collets" clamp down on that.

Cheers

[Kelly]

The new Ripmax Spit cowls are a tighter fit, mine is a tad further back,level with the  two printed rivet marks.

 

It  has also had a nose job.

 

 

[Tim Mackey]

TY Kelvin...mine just wont go any further back than the main bulkhead its simply too small...which seems unsatisfactory as it will only be supported on the blocks. I think I am going to have to put a balsa fillet or similar around the edge of the bulkhead to give the cowl edge support.

[Merlin spit]

Hi Tim ,on my spit the cowl is 12mm from the first panel line ,only leaving about 3-4mm overlap this has been fine so far,and it has had a few hard landings.one of my blocks on the bulkhead wasnt even glued on it was loose in the box ,so i reglued them all with 5 min expoxy.

 they do seem to have a glue shortage at this factory ,i surpose they are trying to keep it light

 

Edited By austen rover on 18/11/2009 18:10:27

[Tim Mackey]

Thanks guys... I have actually had a bit to do to get this sorted. Mine was just not going to slide back beyond the blocks at all - not one bit! I decided that the only way to do it would be to cut the cowl and insert a widening strip. I slit it along the bottom, and inserted a fibreglass and resin bandage, having prised it apart slightly first. I reinforced the edge at the rear with a strip of lithoplate as this is where the bottom mounting screw goes.

My earlier modified prop driver proved useless, as the shaft was hollow, and simply broke off as the collet was tightened. I ended up ( after three attempts ) turning one up in the lathe from a piece of phosphor bronze I found in the bits box. Drilled and threaded the "fat" end to fit onto the short motor shaft, locked with two set screws and simply turned down 5mm the other end for the spinner hub collet.

 

To avoid turning down too close to the motor shaft section, I ended up having to make it longer than really needed, which then made the cowl too short once fitted properly to the fus .
So I made up a balsa ring to extend the nose about 1/4", sanded filled and smoothed off, then spray painted the lot silver to match the rest of the model.

 

I know folk are complaining that silver is wrong....but...... wifey likes it, and it his her model ( so she reckons ).

I also painted the standard gloss black exhaust stacks a slightly more realistic colour.

This afternoon I fitted the receiver and ESC - the Rx is mounted to a small ply plate, and hole is cut in the rear of the cockpit floor. The Rx is then positioned and the plate glued in place. I routed the longer aerial ( AR500 ) back through the "headrest" area and inside the fuse, the final inch ( the active aerial itself ) exiting throught the fus top.

The short fixed aerial will stay within the bubble canopy, and the other reason for mounting the Rx like this is that I can see the orANGE led which alerts me to the fact that the system is switched on, and also I can see if any brown outs occured during flight easily.

 

Tomorrow is servo installation, wing work ( control surfaces etc,)  then fitting the tail feathers, control surfaces, and pushrods, and final fettling.

[Shooting Star]

Hello boys - thought you might like to see the Spitfire now that she is finished.

I love it and think it looks great even if it is only ARTF .

Sticky bun man did help a bit with the build

Today we sorted out a very bad vibration problem when the throttle was on high - turns out that the brand new spinner and folding propellor that we used was poor, the propellor blades were just not fitting correctly in the holder. We changed it for an old one off Tim's Alienator, and now its running much sweeter. Then we fitted all the control surfaces and pinned the hinges with cocktail sticks - he says that it is much safer than trusting to just a little bit of superglue.

We are still waiting for a proper sized pilot, but I might try to carve one out of foam myself and paint him....or maybe her

We connected all the clevis' and set the radio up to give the right movements, then decided to add a little bit of extra protection to the bottom - its pretty rough landing up the Orme sometimes, and I would hate to tear the covering or something .

We put strong clear thick plastic all along the front of the wing, and around the tips. Also put some fibreglass sticky tape on the bottom of the fuselage from the front right down  to the tail.

Then we used some nylon material and fibreglass resin mixture on the middle bottom section of the wing.

Lastly, we printed some waterslide stickers of the Welsh dragon instead of the Canadian maple emblem or whatever it was.  I am looking forward ( nervously) to flying her up at the Orme as soon as the weather gets a bit better.

I am off to sleep now, if the bun man stops snoring

Edited By Shooting Star on 21/11/2009 01:01:54

[Former Member]

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[David Ashby - Moderator]

Very nice job Rahme

[Phil Claridge]

to stop him snoring push a sticky bun in his face two inches higher than the usual place

[Tim Mackey]

Ha ha...  I would still eat it Phil

Right SWMBO insists that we don't let this thing near the Orme until a competent pilot is installed in the office - charming ! Despite trying at least 6 shops so far, and receiving a freebie from David ( TY ) no one has a bod of the right size...all way too big. So, inspired by the excellent job I have seen Matt Halton do with a knife and a bit of pink foam, I set to work. Now I should say in all and complete seriousness...art is really not my thing - at all.

However, I am rather pleased with the first effort...and I reckon once "she" has a bit of make up on, and is tucked away in the office, it aint half bad. What do you reckon guys ?

Ist shot is rough carved and sanded with wifey's emery boards, second is after a coat of epoxy to toughen her up and smooth her off

 not that you need smoothing at all dearest

[Former Member]

[This posting has been removed]

[Tim Mackey]

Well here it /he /she is all suited up and ready to fly.

I decided in the end to make it a pollypilot so please note the mandatory ciggy 

No thats not a bullet hole...but it does look like one eh!

Edited By Timbo - Administrator on 21/11/2009 20:31:09

[Former Member]

[This posting has been removed]

[Tim Mackey]

Maiden flight today in pretty well zero wind at the Orme, so power used all the way.

A bit of a girly throw saw a torque roll sharply to the left - and down!

Caught it ok, just, and then settled in for a flight.

Not quite as I had hoped TBH .

I found my self "hanging" on the elevator a touch, so perhaps she is slightly nose heavy. Not especially happy with the power delivery either ....no shortage of go juice at circa 500 watts and an AUW of 3.12 lbs but I suspect the 9 X 6 prop is simply too small. The darn motor is way exceeding its specified current draw for that prop, and I was hoping to use a 10 or even 11 incher.

I also had a small vibration issue, which showed itself in rattling the tail end of the rather thin pushrods.... a bit disconcerting. This may well be down to the home spun prop shaft extension I had to use - to compenasate for the woefully short shaft of the purple power motor.

I think I am going to change the motor for a spare Mega 22 20 I have here.

This will take the higher amps of a 10 X 6 folder, and its lighter too, so should give me that bit of tailweight  I think she needs.

Balance is spot on the recommended mark, but for me, she felt wallowy, and heavy.

7 minute flight took just 2000 m/a from the 4000 3s pack.

Wifey took some video but it just didn't turn out ...too much sun made it impossible to see the monitor screen, so most of it is just sky

Edited By Timbo - Administrator on 29/11/2009 00:08:46

[Tim Mackey]

Took the plunge and changed the motor. My superb yet slightly elderly Mega 22/20/3e has a longer shaft, but the cowl had to be hacked back to its original length, fettled, and resprayed, but its all done. The mega is also a good bit lighter than the PP, so the tail weight has been removed, and the battery shoved up front further.

She now weighs under 3lb ( 2lb.14oz to be exact ) even with a 4000 ma battery and the balance point, with the new 10 x 6 folder instead of the 9 x 6  is slightly rearward to what it was, which is exactly what I was hoping for.

The slightly alarming thing is the higher Kv mega ( 1500 ) on the same 3s Lipo  was obviously going to be even thirstier than the PP, and the watt meter now shows...

 

wait for it....

 

60A+ and circa 650 Watts, which equals about 216 watts per pound !

Its actually the highest WPlb model in the hangar

Still the big loops should be impressive I did think about using 3 x A123 cells, but thought what the heck, the existing battery fits beautifully and at 4A capacity there should be decent flight times and as I often remind people, the throttle is a proportional control you know.

[Former Member]

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[Tim Mackey]

Hopefully, with the gang of usual suspects next Sunday