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Old 10-07-2007, 01:05 AM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Thanks for the encoragement Tony,

I spoke to Earnie again last week and it looks like we can extend the exhausts 20mm without too much worry although 3W won't guarantee it won't run 'a bit' hotter. I sent the cans back to Earnie on Friday and I should have them back in a week or so. In the meantime, I'm thinking through the throttle servo placement. First thought is that I'll mount the servo inside the cone and bring the pushrod through the cone on an angle. I think I can get away with this as long as I reinforce the cone between the webs with a bit of 3mm ply. I'm still not sure what to do with the choke as there is less room to do the same (but still possible I think). I'll mount the ignition inside the top of the cone with a cooling hole under the mount. Unfortunately, that will make it pretty tight in there to mount the Fromeco ignition battery as well.
I take your point about cg so I will try and get the two 5500ahr Fromeco flight batteries as far forward as I can too. I'll also add a 1.5mm carbon plate reinforcing to the inside of the firewall as it looks like the engine mounting bolts are slightly pulling into the inside face. A bit more weight here might actually help.

Cheers,
Ian
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Old 10-14-2007, 05:58 AM
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Mounting the Cannisters

I got the cannisters back from 3W yesterday and got a bit of a shock. The package had was ripped and the 3W prop drill jig had got loose inside and added a few large dents to the cannisters. Fortunately the cannisters still look to be usuable, just not as pristine as they used to be.
I started where I left off last week, by dry mounting the cannisters in the cone and mounting the cone on the fuselage. Working now from inside the fuselage I pushed the two 3W cannister mounts over the cannisters and slid them forward as far as I could get them. They ended up just behind the undercarriage girder frame which was just behind the reinforcing band on the cannisters so that worked out alright. As the mounts need to sit one behind the other (rather than truly side by side), I decided to fit a base plate and pedestal mount the holders. I used a bit of 50mm x 8mm marine ply to make a false floor behind the undercarriage girder frame. This took a bit of measuring and needed to be cut on funny angles to accommodate the fuselage taper and chines in the floor cross section. I also had to rebate a space for the fuselage carbon reinforcing tape which was easily done with a tenon saw and chisel.
When I was happy that the plate was sitting flat on the fuselage floor, and flush against the rear of the undercarriage girder frame, I glued the false floor in postion using a fairly thick mix of epoxy and ground glass to fill any gaps and get a good bond.
I left that the cure while I worked out the throttle and choke servos but it should now be a simple matter of drilling and screwing the cannister mounts into position.
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Old 10-14-2007, 07:24 AM
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Fitting the throttle and choke servos

Fitting the throttle and choke servos was a bit of a nightmare that took me all day with not much to show for all that fiddling around. Someone will have to explain to me why 3W, who are happy to charge me over $3000 for a top of the line engine, can't manage to fit decent control arms on the carby where the throttle and choke control rods don't interfere with their stock standard headers????
Fortunately, I have a decent heavy soldering iron and I had nothing better to do today than fiddle about, so fiddle I did.
The first decision I needed to make was where to mount the 2 x Hitec 5646MG servos. I looked at Tony's photos and it seems like he has extended the bottom of the firewall with a carbon plate on which he has transversely mounted his servos. I didn't particularly want to add yet another carbon plate and I couldn't see how I could stop the plate from flexing fore and aft with not so good results for throttle control. Tikka had mounted his servos in the fuselage under the fuel tank but I wanted the weight forward. I considered mounting the servos inside the cone and bringing the control rods up on an acute angle but that would almost be fiddling for no real advantage. In the end, I decided to stiffen the inside of the cone with a 3 mm birch ply floor and surface mount the servos on the web between the two headers.
I made a cardboard template of the stiffening web (nothing is square because of the side thrust built into the firewall) and tranfered the pattern onto a peice of ply. I used a tenon saw to cut slightly oversize and finished by trial fitting and using the face sander to trim it just right. I had to cut two triangular rebates into the stiffening to go over the carbon tape reinforcing which again took a bit of work with a sharp chisel. While I was at it, I also made up a 2mm carbon doubler for the inside of the firewall and clamped and glued both of these in with a thick epoxy/ground glass mix.
After the epoxy was dry, I tiddied the inside up with some coarse sandpaper and drilled the carbon doubler for the engine bolts. I re-fitted the engine with longer bolts and added another 3mm tap washer on each bolt behind the firewall to hopefully give some vibraton attenuation. I was now ready to mark out the servos and control runs.
At this point, I found it easier to remove the trumpet and carbureter and fit the headers. I laid out the servos on the engine centreline (not the fuselage - remember 3 degree side thrust built in) using a carbon rod to simulate the control runs and brought the servos back far enough to clear the engine bolts. In retrospect, I should have moved each servo about 5mm closer the the centreline which would have given more clearance to the headers but where I put them worked out (eventually). I cut the servo mounting holes by drilling the corners and using a dremal to make the cut out, finishing off with a flat file.
Next up was to solder the extension onto the choke butterfly. I first bolted the bits together and used lead free silver bearing solder which is magic stuff as long as you have lots of heat and take the time to tin everything properly. I then ground off the excess bolt and tidied it all up with a file and a wash to get rid of any flux.
Unfortunately the arm length is critical and I had three goes at fitting the arm before I got a length and position where the connector (just) misses the carby housing at one end and (just) misses the header at the other. Even then, the control rod needed a few bends which is when I found out that Precision Aerobatics heavy duty control rods are very brittle. I used Nelson alloy connectors at the carby and a ball link mounted onto the Hitech metal servo arm. I needed to grind the 3mm bolt holding the ball back to the face of the lock nut to get clearance between the servo arm and the servo case. A cutting the metal control rod to length, I soldered a threaded coupler on the other end and joined it all up. Three hours and two rods later, I had the choke working properly.
Fortunately, the throttle linkage was much simpler being an almost straight control run. I did have to reposition the extension on the carby butterfly valve to 45 degrees rather than right angles as the 3W part would suggest. I fabricated a new throttle arm from brass which worked much better.

Not much to show for a days work but I guess that's modelling for you .
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Old 10-14-2007, 07:50 AM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Ian nice job on the throttle/choke servo , dont know how well soft solder
is going to hold up though . I've done a few crappy carb set ups with my
old ZDZ engines ,being rear of the engine they are a real pain .

I have always favoured a bolt on arm than a stuck on one . I use a 30mm
gal washer and cut it in half , then drill a series of holes along its length
and persto , a cresent shaped arm .

Stu .
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Old 10-14-2007, 08:03 AM
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Soldered joints

Thanks Stu.
I take your point about the solder which is why I bolted the extension first and then solered the whole lot together. I can attest that it is a proper pain in @#$# to get off and I litterally had to grind the head off the nut and then use lots of heat to break the bond. I'll make sure that Byron keeps his eye on it anyway.
Cheers,
Ian
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Old 10-21-2007, 08:19 AM
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Ignition System

Another weekend where doing the domestic stuff got in the way of building time but I did find time to mount the ignition and work on a few other bits.
After a bit of to-ing and fro-ing, I decided to mount the ignition outside the cone, mainly for cooling, and on the right side to separate the 'spark' from the radio electronics.
It was a simple matter to mark the cone for the four mounting bolts using the ignition as a template and drill the 4mm mounting holes, making sure that I stayed clear of the internal reinforcing. I used eight 4mm x 12mm nylon bolts and four lengths of tygon fuel tubing to make a vibration mount (Tony's great idea) that sits about 2mm clear of the cone. All this involved was to first push a bolt through the cone from the inside and 'screw' it into one length of tygon. Then, 'screw' a second bolt into the other end of the tygon tube leaving the bolt slightly proud to fit into the ignition mounting point. I repeated this step for the other three mounting points then cliped the ingintion into the four mounts and tightened the four top bolts to hold the ignition in position. I used 2mm cable ties over the tygon at each bolt to make sure the whole assembly stayed assembled.
Next, I marked and drilled a 12mm hole and threaded the hall sensor, ignition control battery lead and charging jack lines all through a 12mm rubber grommet and fitted the grommet into the pre-drilled hole. All that was left was to cover the ignition and hall sensor cables in spiral wrap and epoxy some cable clips onto the outside of the cone to keep it all neat and tidy.
While I had the epoxy, I also glued two strips of 6mm ply inside the reinforcing to take the servo screws for the throttle and choke. The attached photos should give you the idea.
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Old 10-21-2007, 10:19 PM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Looking good dad! I really like those clips that you've used. Cant wait to see the whole thing with my own eyes in a weeks time!
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Old 10-28-2007, 07:58 AM
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Ignition System - Part 2

Byron gets back from his overseas trip on Wednesday; I hope he likes what I've done so far This weekend, I finished fitting the ignition system and started on the cockpit. I started by laying out the component parts (Fromeco 7.4V 2500Ah Lithium Ion ignition battery, Smart-Fly Ignition Cutoff and Badger ignition switch) and trying to keep everything except the switch inside the cone. That way all I have to do is disconnect the battery and ignition cutoff 'receiver' leads, throttle and choke servo leads and fuel lines to remove the cone.
I made up a simple battery box out of lite ply to mount the ignition battery on the inside face of the firewall. The box was mounted the box onto the firewall with four brass wood screws and has a tunnel under the mounting for a velcro strap. I soldered a female Multiplex 6 pin connector on the battery and the male connecter to the ignition switch. I soldered a female Deans 3 pin connector to the switch outlet and replaced the Futaba male plug on the ignition cutoff with the male Deans.
All the ignition system connectors are now 'idiot proof' in that each connector only fits the correct linkage and the poles cannot be reversed.
I glued the ignition cuttoff fibre optic 'transmitter' and 'receiver' modules to some small plywood mounting plates that I secured inside the left side of the cone with 3mm cap head bolts and nylock nuts, heeding the manufacturers instruction to keep the 'receiver' as far away from the ignition as possible. I cut the fibre optic cable to exact length and tightened the retaining screws to hold it in place. I then wrapped the battery in foam rubber and secured the battery in it's box with the velcro strap. After some careful measurements to make sure I cleared the wing, I mounted the ignition switch on the right side of the forward fuselage with the supplied 3mm countersunk bolts. All that was left was to connect it all up and turn on the switch to check the LEDs were working as advertised. I'll tidy up the wires inside the cone with a few cable clips after I've mounted the Emotec DPSI 2001 RV power servo interface in the front of the fuselage.
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Old 10-28-2007, 08:32 AM
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Cockpit Templates and Oil Cooler

I am always intrigued that IMACC Rules require a pilot and instrument panel to be visible but a lot of models haven't got these refinements. Extra weight I hear you cry but if it's the same for everybody......I suppose that's why the rules require a penalty on those aircraft that don't comply. Never mind, with a 170 stump puller up front and the weight I saved on replacing the aluminium wing joiner with carbon, I can aford a little bit of extra weight in the cockpit.
I started out by using some art paper to cut templates for the cockpit ploor and instrument panel. When I had these fitting nicely, I used these templates as patterns for some stiff corregated cardboard on which I made the final adjustments.
I had purchased a Lite Pilots 40% 'Blue Bob' which has some nice detail but always looked a tad small, and more so now that I had some 'context'. It looked like I needed to go back to the drawing board but I discovered there isn't a lot of choice in pilots for 40% scale without going stupid and getting a custom made 'Axel' doll made. Eventually, however, I did find a moulded Life-Like 40% pilot bust which is a full inch wider at the shoulder than 'Blue Bob' at www.hppilots.com. Roy had an unpainted one in stock for US$51.40 including shipping and I expect it to arrive early next next week.
While I was waiting, I painted some aluminum mesh in heatproof white for the oil cooler. When it was dry, I used the art paper to make a template and cut it to shape to fit the cutout I had already made in the cowling. I epoxied the grill in place using a couple of weights to hold it firmly in place while the epoxy cured. I also used the 3W drill guide (that caused so much grief with the cannisters) and a drill press to drill the PT 34 x 10 propeller for the mounting bolts and mounted the cone, cowling and propeller. I was pretty happy with how this bit turned out.
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Old 10-28-2007, 09:11 AM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Ian,
I would try to keep all the associated ignition wires away from the servo wires as much as possible.
Only my thoughts.

Loza
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Old 11-05-2007, 05:57 PM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Thanks Lozza,

That sounds like good advice all round. I think that I'll need to make some cable extenstions but, as much as possible, I'll keep I'll keep everything ingnition on the right and everything else on the left side of the fuselage. I haven't quite decided where to put the flight batteries but I'm leaning towards either just inside the fuselage/cone join or on each side of the throttle.choke servos on the reinforcing plate. Unfortunately, there isn't a lot of room in there and electrical interference might be a problem.

No work on the beast this week as Byron got back from his overseas holiday on Wednesday and we spent time catching up. We did get a couple of gliders onto the slope at Stanwell Park and my trainer up at the local field to sort out his thumbs (pretty rusty!!!) but he didn't break anything. The landings...well just lets say I'm glad I spent time strengthening the undercarriage...of course it was very turbulent...but I think Coota is just a bit too close

Ian
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Old 11-09-2007, 08:37 PM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Hello.

Very nice plane you have here. I have the same one and here are some experiences.


I've had about 150 flights with mine now, and the undercarrige is as good as new. Had a few hard landings on a short grass field, only 60 meters long, but nothing has been broken, and no reeinforcement has been necessery. Excuse my english, I'm from Norway.
I have a 3W 157 in mine, plenty of power, and I mounted the engine straight to the dome, no spacers, 2mm gap betwen the spinner backplate and the cowl. Looks nice. I have my batteries(2x2800 Powerox Lipo batteries and 1x3300 6 volt Nimh Sub C cell) installed at the rear end of the canopy.

Throttle servo installed inside motordome, with a long arm, and the pushrod is maybe 2 inches long, having a nice angle to the throttle arm on the carb. Ignition box is installed on the inside of the motordome ceeling. No problems there.

I use 2x 5955TG on each aileron, 1x5955TG on each elevator, and 2x5955TG on the rudder. This has not given me any trouble, plenty of throws and power, knifeedgeloops can be done all day

Not sure where CG is located, but it flies inverted using no elevator correction, roll over to straight flight, heading is perfect. Same thing straight up, and down. Maybe just lucky, but I'm glad it flies like this.

Bad thing: The rod that goes through the hinges on my rudder, is eating up the holes in the hinges, making them bigger and bigger. I used some Festo tubes, redrilled the hingholes, and glued small tubes inside the new holes. Fitted a carbon rod and, wholla, nice and tight again, should be ok now. Thats the only "bad" thing with my Extra.

Next month I start building the new 3,5 meter Edge 540 from Xtreme, and the 2,6 meter Castrol Edge. Looking forward to it.

Hope to see your bird in the air soon. Best regards from Norway, the Winterland
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Old 11-10-2007, 07:07 AM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Tikka,

It's good to hear from you again. How's the weather up north, we're just coming into our summer flying season in Australia. I'm glad to see that you are still flying your Extra 260. Byron and I followed your build and I know that it got Byron interested in the X-treme Composites version. Thanks for your tips, they all help. It sounds like I need to go shopping for some 1.5 mm bearings and change the rudder pin over to carbon.

Cheers,
Ian
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Old 11-10-2007, 07:54 AM
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Instrument Panel

I felt like fiddling today although it was all to a good purpose. I'm working up to the job of fixing the canopy into the canopy frame which I suspect isn't going to be as easy as it sounds. Of course I going to complicate the process by fitting an instrument panel which will need to installed after the canopy. Although there is plenty of room underneath the canopy frame, the 25mm flanges mean that I can't prefabricate a complete panel/coaming assembly. Instead, I'll need to make the parts individually and only glue them together when I've fitted them inside the frame. That means that I need to have the parts cut to the templates I made last week and dry fitted before I can fit the canopy.
I wanted a scale panel without being stupid about it but there isn't anything commercially available in 40% scale. No problem, I'd could build my own. I started by downloading the Extra 300 panel template from Extra Aircraft and scaled the image by trial and error before printing a 40% scale template showing the instrument panel layout. I then searched the net for aircraft instrument/guage/parts suppliers to find good images of the various instruments I'd need (it took a bit of seaching to find some of the engine guages). I did some quick calculations to work out the correct 40% scale dimensions for standard 3-3/8 in and 2-1/4 in guages and re-sized the images to scale before printing them onto photographic paper with a colour ink-jet printer. I individually cut each instrument from the sheet and layed them out over the template. I was pretty chuffed to find the images were correct scale for the template so my figuring must have been OK .
The next step was to transfer the template onto a sheet of feather light art board which I had sprayed light grey for contrast. Cutting the art board was pretty easy with a fine tenon saw and I finished to exact size using the face sander and a sanding board for the inside corners. I used art glue and a ruler to carefully fix each cut-out instrument in it's proper place. I then added a few micro-switches and circuit breakers from Dick Smith for effect. I made the main knobs from a carbon/aluminium arrow shaft with a carbon rod inner (gives a nice aliminium ring around the top) and cut the top off a Dick Smith plastic knob for the magneto. The finer ones were made from Nyrod inner filled with a toothpick and painted black. The knobs were all glued over the photo with a small dab of super glue. The finished product looks really good and weighs bugger all.
I have attached the photo sheets of the instruments correctly scaled to 40% just in case anyone else wants to spruce up their model, as well as the build photos.
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Old 11-10-2007, 07:06 PM
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Re: Another Ozzie Extreme Composites 40% Extra 260 Build

Wow dad, that came out alot better than i was expecting! I like very much!
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