Trisquire

Would A123 cells have adequate discharge rates for this type of plane?

Tom

chronos333

A123's voltage drop is too important above 40amps to be useable.
You have to run them 9or10S2P which almost equates nimh's weight!

Trisquire

It might equate nimh's weight, but the flights would be a lot longer than nimh.

Tom

rainedave

My Feedback: (1)

From the little I've read about A123 cells, their advantage lies in the fact that they can tolerate higher charge rates. The recommended safe rate for the average lipo is a 1C charge rate. A123s can supposedly be charged safely at 2C or higher, if I'm not mistaken. Ounce for ounce they have a lot more capacity than NiMHs but a bit less than lipos, so it's the higher charge rates that make them attractive compared to lipos.

chronos333

But weight/performance wise, nothing beats the lipo these days.
I hope it will change[&:]

Trisquire

And the price.

Tom

chronos333

And most of all safety...

can773

My Feedback: (1)

Re: Power Supplies,

There is not much that can beat the Iota DLS-55, 740W for $100ish US. A single supply can handle two 10s packs at 5A and a third at 4A. The 55A is probably overkill, but they also do a 30A and 45A.

Plus it doubles as a very good charger for the 12V batteries if you charge at the field

chronos333

that's right, but a coswell PS @ 15$ ain't bad either

Bootalini

Well, it was back to the wings this weekend. A busy couple of days but I still managed about 3 hours of 'model' time which was enough to cut the ailerons out of the wings, cap and hinge them to the wing panels and then sand everything flush. As per the stab halves I used 1/4" balsa to cap the wing portion just ahead of the aileron and 1/2" to cap the front of the aileron itself. The 1/2" wood ensures a lot of area remaining after beveling the ailerons and provides a good anchor for the aileron horns.

Next on the 'to-do' list is to cut the tips and tack glue them into place. I'll then carve them and sand to a rough finish before I break them off so I can hollow them out.

Atlanta 60

My Feedback: (18)

Bump...

How's it Going?? Hope all is Well!!

Chuck

Bootalini

I'ts been a while since I last posted. I've had a lot on the go lately.

As you can see in the 1 photo, I now have 2 cowlings which are lighter and a better quality than the original MK product. Anyone seeking additional info on this can PM me.

Wings are nearing completion with only the wheel wells and servo bays to be trimmed. Next on the list is attaching the new cowl and shaping the lower fuselage. I'll soon be ready to start applying the 1/2oz cloth. I'm going to use MinnWax Polycrylic to apply the cloth and and the same with corn starch to fill the weave. For paint, I've pretty much decided on Auto-Air water based paints for the color coats and I'll use a standard automotive clear to seal the whole mess . Anyone have recomendations on what I should use as a first coat on the bare wood as a sealer before I apply the cloth and water based Polycrylic??? Dope maybe?

I'm also in the process of designing a new motor mount which PTXMan will fabricate for me. The mount supplied with the motor package is quite good but it's "X" shape centers on the back of the motor which would normally be fine for most airplanes. The issue with the Aurora is that it was designed for beam mounts and as such it has a minimalistic firewall. Two of the mounting points on the Hyperion aluminum mount would be left hanging with nowhere to attach to. My solution is a larger rectangular mount with the holes for the motor bolts being offset as required. Anyway, have a look at the attached photo and it will become clear. The stock mount is next to the draft CAD drawing for reference.

Jeff L

Atlanta 60

My Feedback: (18)

Woot!! Your going again!! Great!! Looking Good!!

Chuck

mmattockx

Jeff,

Good to see you back on the Aurora project... I have no first hand experience with the PolyC (yet), but I am planning on using it for a number of upcoming builds, so I have been researching and paying attention to posts about it. A number of people have used Deft sealer with good results and it seems any laquer based sealer works OK. At least one person used nitrate dope with good results as well. You must use something before the PolyC or the wood will warp and swell because of the water base.

Mark

Bootalini

It's been a while since my last post but I had some time this weekend to hit the shop and get going again. PTX Man and I spoke about a week ago ref fancy motor mounts and the problem (in this case) of access to the upper 2 bolts. The front of the motor has a rather large flat area which makes getting at some of the motor mounting bolts very difficult. In the end, I decided to scrap the elaborate plan and go with the very simple solution of building a second firewall and positioning it forward so that it sat 1/4" behind the motor which minimized the length of any mounting pillars while allowing some air flow between the mount and motor for cooling purposes. See the photos....all will be clear.

After fabricating the second firewall and trimming it to size, I once again mounted/suspended the motor and spinner from the fuselage nosering which provided the required alignment and thrust angle. I then nudged the firewall (from behind the motor) up against the X shaped aluminum mount and then bolted everything together. I tacked the firewall to the fuse sides with a few drops of Zap and then pulled the motor out. After that, I re-mounted the motor to the new firewall as per normal (not using the fuse nosering). This was to double-check that the firewall positioning was in fact good.....funny how I've learned to double and triple check things!! Anyhow, all works well with the motor being able to be dropped-in and mounted quickly and easily.

Check out those MK Magic 60 plans I got from Willy. Might be my next project using my YS .61RE......hmmmmmm. Thanks Will!

Jeff

Bootalini

As of tomorrow, I'm officially on holidays for the next 6 days.....lot's of time to get a good surge in on this project. I sure don't remember taking this long to ever build an airplane in the days of old!

The wings are done with the exception of a bit of filling and sanding. You can see some filler in the photo.

With the motor mount taken care of, I went ahead and permanently glued the front upper balsa block to the fuselage, rough sanded the area and then added a little filler.

Next step is fitting and mounting the belly pan. After some minor trimming and sanding, I found that it fit quite well. Ref how to fix the cowl to the fuse, the "tongue 'n' ridge" method you see in the photos is per the plans. The Cosmos 60 I built many moons ago used the same method and it works well as long as the thin ply parts stay well glued to the glass cowling. After the cowl is mounted, I'll be able to finish shaping the fuselage and nose area near the nose ring/spinner. I could be applying the glass cloth by the end of the week!!

Jeff

Atlanta 60

My Feedback: (18)

Jeff..

She Looks Awesome Dude!![sm=thumbup.gif]

Chuck

Bootalini

I just finished mounting the belly pan to the bottom of the fuselage. As previously mentioned, I pretty much stayed true to the MK plans including the mounting bracket method you see in the first photo. I've started trimming the fuse in the area of the pan and nose ring. The air hole cutout in the cowling is still pretty rough and you can see where I'm planning to cut the pan for the nose gear.

I also lined the "cockpit" using 1/16 balsa sheet. Ref what will be inside the canopy, I like the setup seen in the attached photo. I'll glass the floor of the cockpit before I add any of those details.

Jeff

Bootalini

It's been a while since my last post but I've made significant progress. I've been filling and sanding (and repeating the process) trying to get a perfect finish prior to applying the glass cloth. I'm just about there. Ref the orange tinge in the photos, that's a result of using orange colored automotive glazing putty as my final filler. For those that have not used it, it allows for an incredibly fine feathered edge and smooth finish. It's also a pleasure to sand. The ol'e tack-rag treatment prior to applying the cloth should remove most of the orange dust.

Jeff

rainedave

My Feedback: (1)

Good to see more progress, Jeff. It's looking great. I swear by that red/orange glazing putty. It dries so fast, and like you said, it's incredibly easy to sand.

David

Bootalini

I'm just about to start applying the finish. I thought it would be of interest if I quantify exactly how much weight my slightly non-traditional finish will add to this airplane using the following technique:

Prep
-2 or 3 coats of clear dope to seal the wood, sanding as required
-apply 1/2 glass cloth using water-based Minwax Polycrylic
-apply at least 2 additional coats of Minwax before any light sanding
-afterwards, as many coats of Minwax as required to get a nice smooth base finish

Paint
-Auto-Air water-based colors...scheme as per Steve Helm's Aurora
-Standard automotive clear-coat, brand TBD.

Starting reference weights
-Fuse (minus belly pan, motor, and nosegear) = 562 grams
-Single wing panel including aileron (no gear or servo) = 205 grams
-Stab half, including elevator = 72 grams

Jeff

Bootalini

I applied 3 coats of clear dope to the fuse and 2 coats to everything else. I can't even remember the last time I used dope......likely 20 years at least but I was reminded in a hurry about how harsh that stuff is. My wife sure appreciated it.

After lightly sanding the fuse with #400 wet/dry, I was ready to apply cloth. I started with a small peice in the cockpit area. A test run really although I did try the cloth/Polycrylic over dope method on a scrap peice last week. As you photo shows, I didn't skimp on the Minnwax but as I'm writting this less than an hour after I applied the cloth, the Minnwax is almost completely dry...and not a hint of scent from the Polycrylic!!

Jeff

rainedave

My Feedback: (1)

Jeff, how does the polycrylic sand? Does it roll up?

Eggert

Hi. Love to follow this thread. My first Pattern ship was a Curare and I adore all the old pattern ships. Since everything seems so well thought out in your build I'd like to question your choice of motor ? The 4045 will pull a pattern ship of 11 pounds with ease. Following the not so very scientific rule of thumb for electrics : Motor weight (in gram) times 10 equals the combined weight of the aeroplane including batteries ( also in gramme ), would suggest you should use a motor of ca 400 gramme and perhaps only 375 gramme
I'd figure taking 150 gramme out of the nose of the fine aeroplane would be a nice thing to do.

Lets hear from others whether the rule applies.....

Bootalini

Eggert, I'm having trouble interpreting what it is you're suggesting. Maybe someone else can lock-on?

Latest update: The entire fuse has been glassed and 3 coats of Poly applied to the cloth. I tried test sanding in one small area using #400 wet and it seemed to work just fine....no rolling. More to follow.

Jeff