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Chris Foss Xtra Wot


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Posted by Peter Jenkins on 02/07/2020 09:23:55:

Do you use the Max/Min function Bob? That needs a spare channel on the Rx though. You also get motor rpm if you connect to one of the 3 phase motor leads. If using a gearbox you can enter the gear ratio used to get prop rpm.

Connecting to FrSky I just use consumption, pack voltage and altitude. I had to go away and check the manual to remind myself what's available on the Unisens-E and what you meant by min-max! I have set up telemetry displays to show max power, max height on my transmitters but I tend to forget they're there most of the time. I generally browse the logfiles at home out of curiosity or if there was an issue but I'm not chasing every watt so I only tend to monitor lowest cell voltage for warnings of poorly cells. Any value that needs warnings (pack voltage, altitude) are set up as logical switches triggering special function 'play track' warnings, all within OpenTX.

I think it's the Bolero that I set up a motor lead for RPM but I found it a bit unreliable - sometimes it triggers, more often not.  TBH unlike with IC I don't worry about the RPM of an electric motor, after all I set it up with a known kv and known battery voltage so it's not going to vary that much.

Edited By Bob Cotsford on 02/07/2020 11:37:29

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Yes, I also rarely use the rpm figure as in my case I have a contra prop that is driven through an epicyclic gearbox so there's no telling what the individual prop rpm is! All I get is the calculated rpm on a 13.5:1 gear ratio! As you say, the key parameters are all covered by amps, volts and capacity remaining. I actually now only look at the max height reached as that tells me if I broke the 60 deg rule and ended outside the aerobatic box. Obviously, the further out you fly from the 150 m datum the higher you can be without going out of the 60 deg max angle! I also use the Tx (JR XG11) to alert on remaining capacity at 1,000 mah. Not usually a problem if I'm flying the schedule as I usually have between 1,500 and 1,800 mah remaining out of 4750 mah at start.

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Today was quite productive.

Primer applied to the various bits that are white and need to be black

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I had already primed the fuse decking so I set about cutting teh front section out which will be the battery access hatch.

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Back to the outside spray booth and black topcoat applied.

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Control linkages fitted to the ailerons (I've already done the tail ones), using a Z bend for them servo end, keeping it nice and simple.

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Servo wiring sorted and for the wing I'm using Maxloc (Ashlock) connector, one plug instead of 2 to connect at the field.

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Other bits done, cowl mounting blocks fitted and cowl cut out for the motor shaft and the air intakes. U/C drilled and fitted along with wheels.

So I couldn't resist the temptation to see what it all looks like loosely assembled (I needed to get the fuse up to a position where I could check the C of G as that will determine where the battery pack goes and the support platform for them. Fortunately Chriss Foss gives a fuse only C of G and having checked it out, the batteries should fit into an easily accessible space. So that will be tomorrow's main job, build the platform then permanently fitting the top deck and making the battery hatch.

And this is what it looks like on the bench, 'posed' outside shots will be tomorrow. I am rather chuffed with the look.

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Thanks Peter, and, yes, the colour scheme was to aid orientation but I also wanted to break up the large areas of black and orange hence the colour reversed lettering. What it will be like in the sky is another question which I should have an answer to In the near future (hopefully).

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Got to say - you can't beat orange and black, can you. That really does look special Ron.thumbs up

What a wonderful idea to give a fuselage only balance point, I'm off to the La7 thread to ask if anyone can chack their completed models without wings!

Is that the Silhouette Cameo cutter? Having spent probably £50 on cut vinyl in the last few months and seeing your results I might keep an eye out on the second hand sales sites.

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Thanks Bob, give me 30 minutes and I'll balance my LA-7 fuse for you.

Yes the graphics were cut using the Silhouette Cameo cutter, it 'was' the wife's but it's now found its way into my building bits and pieces inventory. I must say that it has completely changed the way I now do things and next up are paint masks (I know a lot of other formulites use it for this as well). In fact I tried out some scale rivets, having just bought some from Mick Reeves, 'designed' them in Fusion 360 and cut them in some vinyl, results are excellent. Having also bought some panel lines from MR I'm now going to do those too, all in preparation for the BF110 build due to start next week.

Edited By Ron Gray on 03/07/2020 10:08:31

Edited By Ron Gray on 03/07/2020 10:11:08

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I’m no expert Gary, but happy to run through what I did, well it worked!

As I only had a 12 x 12” cutting mat I was restricted to cutting within that footprint so it depended upon the letters being cut, eg the W had to be printed on its own whereas R and A could be printed together, obviously I’m referring to the larger letters on the wing. But I’ve now got 12 x 24” cutting mats so have more flexibility to print more in one go.

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The cutting mats have a tacky surface (different levels of stickyness are available) so you just smooth the film out onto the mat and it stays in place. A problem can arise where the film detaches itself from its backing In which case remove the backing first. I tried both ways and didn’t have any problems with either method. In fact the biggest problem was getting the film off the mat, you just need to be careful and have a sharp scalpel to hand to assist!

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And the fun of doing it. As I said earlier I’m now into rivets and panel lines so that will save time and money. The other thing I want to try is cutting thin aluminium self adhesive foil, if I can do it then the Warbird Replicas Mustang is my ‘target’, not just panel lines but ‘scale’ panels!

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Last little bits done today, well I say the last but there are bound to be more. Didn't get round to taking the outdoor shots as it started to rain this afternoon and into the evening but there's always tomorrow!

Battery box and platform. I 3D printed the box as the printer could be getting on with that whilst I was doing other bits.

Battery box mounted on ply platform. I may well re-print the box with lightening holes but we'll see how it goes. It's not glued together just screwed to cater for this eventuality.

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10s 5000's sit in there nice and snug (got to do the retaining strap!)

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I stuck bearers to the fuse sides and the platform is screwed to them so that it sits, more or less, on top of the wing.

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Battery box in place.

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And testing out the insertion of the batteries through where the hatch will be.

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There's quite a bit of room for the batteries to be moved to achieve the C of G.

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After I had glued the front deck in place it was time to make up the battery hatch cover. Before gluing in place I covered the fixed formers with some masking tape to prevent accidental glueing taking place!

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Then I cut out 2 top former pieces onto which the hatch will be stuck and to keep them in place whilst the cover glue dries I hot glued them to the masking tape.

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The cover was then glued on using Gorilla Glue (brown).

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The canopy was attached using very small socket head screws. I like the look of the fixings along the edge of the canopy and prefer it to just glueing the canopy in place.

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Other jobs carried out today have been the soldering of connectors onto the ESC and fitting it to the underside of the engine mounting box together with drilling the firewall for the ESC leads. The cowl has been fitted with its side cheeks, these have been reinforced with balsa base plates which also makes it easier to fit them to the fuse.

Tomorrow should see the hatch finished off, Rx fitted and a BEC installed to power it and the battery restraint straps fitted. And that will be it, all ready for its maiden flight.

Edited By Ron Gray on 03/07/2020 22:30:36

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IT'S FINISHED!!!!!!

Fitted the velcro restraint straps to etc battery box and then finished off the construction of the access hatch, using a ply tongue for the front edge and a spring latch for the rear.

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And so to the outdoor shots

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A couple of shots of the underside but the iPhone has difficulty in rendering true colours when there is a dark background to contend with, the lettering is actually the same orange as the topside of the 'plane, not yellow as it appears to show here!

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There still is / are one or 2 jobs to be done, I'm not happy with the spinner as it is a bit too pointy plus could do with being 1/2" smaller diameter, so it's over to the 3D printer and print a new one. I also don't like the 'bandy legged' stance of the UC so may well change that for a more 'straight legged' part.

Hopefully you've enjoyed this build 'blog', I've certainly enjoyed it and thanks to all those who have commented over the last couple fo weeks. Next up the Warbird Replica BF110, but that wont be for a couple of days.

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