RE: Aurora 60 Build Thread - Electric Power
 

It's looking great, Jeff. And you're making really fast progress. In the meantime, you can order the paint or dope while you're waiting on the cores.:D

RE: Aurora 60 Build Thread - Electric Power
 

Flying foam did a great job for my wing cores. I actually emailed the guy my autocad drawings and he was able to ship the wings and stabs a few weeks later.

I actually had the trailing edges of the cores come down to a sharp point, and they were still cut perfectly!

RE: Aurora 60 Build Thread - Electric Power
 

Progress continues as we start the Thanksgiving holiday. The vertical fin has been permanently glued to it's base block which is only tack glued to the rear main fuse. I then carved that base block which essentially fairs the fin into the main fuselage. Generally speaking, I had to do a bit of trimming here and there to achieve proper fin positioning and alignment as the sum of several small errors had to be compensated for.........but I'm confident that she's straight.
The rudder pieces are almost ready for assembly. I'll be using 2 sheets of 1/4" balsa sandwiching a 1/32nd ply center. I like this method as it ensures a straight control surface and allows me to keep track of an accurate center as I shape the piece. The ply center also toughens the edges/corners. I'll be cutting slots into the large piece of ply which is where the hinges will go into the rudder. After the vertical fin is done, I'll pop off the main block and once again hollow inside where able. I'll then install the carbon dual elevator pushrod system that you see in the photos. It arrived today in the mail from Central Hobbies and looks to be a quality unit. I also received a Gator plug-in adjustable stab mechanism which will be installed a bit later.
Speaking of hinges, I have to make yet another trip to the local hobby shop to get some! As mentioned at the start of this thread, I'm starting back into the hobby from scratch after a long layoff. After I stopped flying years ago, I slowly got rid of everything including hardware. As I progress on this project, I'm finding that I need this and that....stuff that modelers usually have lying around. I don't mind the nickel and dime factor, it's the repeated trips to town that annoy me. Maybe I should plan a bit better....hmmmmmm?

Jeff L

RE: Aurora 60 Build Thread - Electric Power
 

Nice job on the vertical stab. One nice thing about using the plug in horizontal stabs is they really simplify the complexity of the wood parts in tail area.

RE: Aurora 60 Build Thread - Electric Power
 

The vertical fin and rudder have been shaped. This phase has been the most tedious part of the project thus far.

A quick trip to the hobby shop and I had the hinges required to hinge and tack the rudder to the fin prior to sanding. As you can see in the 1 photo, I slotted the rudder's thin ply core to accept 4 hinges. The 2 rudder horns for the pull-pull will later be attached near the rudder's bottom with horn bolts going thru the bottom hinge. I then sandwiched the perimeter ply core with 2 quarter inch pieces of balsa plank on either side. Before tacking the rudder to the fin, I carved the rudder to it's rough shape to minimize the sanding once the whole unit was together. While the fin is structuraly strong, some parts are fragile to handling during the carving and sanding process.
Next step is to break the entire fin unit from the fuse then hollow it's main block from the bottom. Removing this unit also gives me unrestricted access to the rear fuse innards as I've yet to install the elevator pushrods and antenna guide. Once all those steps are completed, I'll permanently glue all the carved blocks back into place and finish the shaping and sanding.

Turkey last night, turkey sandwiches for lunch today and turkey leftovers for supper tonight. Enough for this coming week's lunches as well. Sound familiar??

Jeff L

RE: Aurora 60 Build Thread - Electric Power
 

The fin assembly broke off nice and clean. For hollowing, I start with a straight blade x-acto to remove the big chunks. I simply cut 'v's into the wood and pull out large pieces. I follow with the drum sander mounted to my Dremel tool....works great!

In the end, I wonder how much weight I'm saving? Hard to tell really but every bit counts I guess.

Jeff L

RE: Aurora 60 Build Thread - Electric Power
 

In an effort to shave additional grams, I removed more balsa from the inside of a few of the blocks I had already hollowed out. As well, I cut out the air vent holes in the bottom of the fuse just behind where the glass cowling ends. I cut those vents are as per the plans to maintain an authentic look.
With the electric setup, instead of a header and pipe running down low the inside of the cowl, I will have the ESC either just ahead or behind the nosegear depending on balance requirements and the battery also hanging low in the vicinity of the CG. The rear vents seen in the picture combined with the standard vent that I'll cut in the front of the cowl should provide adequate cooling of the electrical components.

Just weighed the fuselage including all blocks and vert fin/rudder (minus canopy and cowl) and I'm sitting at 590 grams.

Jeff L

RE: Aurora 60 Build Thread - Electric Power
 

1000+ hits!! That's nice to see. Hopefully these build threads serve to motivate and provide insight into different building techniques. I know I've certainly enjoyed following 8178's progress.

Jeff L

RE: Aurora 60 Build Thread - Electric Power
 

Just finished installing the elevator pushrod system, the rudder cable guides and the antenna guide.
A fair bit of work was required to install that pushrod system from Central Hobbies. You must ensure a linear path (minimize any bending) for both the carbon rods and their housings, otherwise you build significant friction into the system. In the end those cool looking carbon rods exiting the fuselage with high quality couplings to the clevices add up to a classy setup.

Time to start re-gluing blocks and the vertical fin to the fuse and proceed with final carving and sanding.

RE: Aurora 60 Build Thread - Electric Power
 

The 2 rear bottom blocks and vertical fin assembly have been permanently re-glued to the main fuse. Photos show the elevator carbon rod exiting the fuse, the rudder cable guide, as well as the antenna guide tube exiting the bottom of the tail.

I'd say she's starting to look like an Aurora! I'm hoping to hear back soon ref wing/stab cores so I can get on with the rest of the project.

RE: Aurora 60 Build Thread - Electric Power
 

I'm preparing the nose section to accept the nosegear mount. The original Aurora (and Cosmos) have the nosegear offset from center line to minimize the amount of offset required in the header. Since I have no header to contend with, I'm going to centrally mount the nosegear. The 1/4" plywood gear mount will be extra wide though and will contain 2 sets of holes/blind nuts to allow both a central or traditional offset mount. Again, I'm looking to retain a glow motor option in case I change my mind one day.

RE: Aurora 60 Build Thread - Electric Power
 

Christmas came early today!! A hearty thanks to:

-Ryan McLaughlin who donated an MK nosegear and Supra mains to the project. He had these lying around gathering dust and although used, they're in great shape and will be perfectly at home on the Aurora. I don't know Ryan from previous which illustrates the camaraderie and good-will within the vintage pattern community!!

-Peter T.......aka PTXman who's been a great friend and cerebral source these last 18 years. Pete donated all the goodies you see in the box including 2 sets of those hard to find Gator Plug-In Wing Adjusters. I was having a hard time finding those things.

I tried calling Flying Foam today but no answer. I sure hope I can get cores delivered in time for the Christmas holiday.

RE: Aurora 60 Build Thread - Electric Power
 

Ryan is a great guy, also our national pattern champ in masters [8D]

I really like this plane!

-Mike

RE: Aurora 60 Build Thread - Electric Power
 

BTW forget MGS, you can't get the hardener. West is ok but not my first choice.

Hint: Look into Jeffco 3138/1308NC

-Mike

RE: Aurora 60 Build Thread - Electric Power
 

No problemo. Im happy they found a better home in a great looking model. I think that was the last of anything 'pattern' in my shop <sniff>.

If I didnt have 40 projects in the que already, Id take a crack at machining a variable pitch mechanism for your electric along the lines of this pic. Cant you just picture this bad boy with a 3 blade prop? It would be a totally retro-vintage touch. I could forsee 10 meter smokin takeoffs.... & probably even shorter 'braked' landings <g>. Didnt Steve Helms run one of those units on is Aurora circa late 80's? We would of course fix the F5B folder blades into permanent 'stick-out' position.

RE: Aurora 60 Build Thread - Electric Power
 

It's been a while since my last post. Progress has slowed for a variety of reasons but essentially I'm waiting for cores and my Hyperion 4045-10 motor to arrive. I'll be off to the races again as those things arrive. Of course the horrendous weather we've been having in Colorado has not helped the mail to arrive in a timely manner either. Did I mention my back is sore from all the shoveling?

In the meantime, I completed some work in that area of the nosegear. I made the "tank floor" that the nosegear mounts on out of lite ply so I though I had better reinforce that puppy just a bit. Combined with the white spacers seen in the photos, the nosegear will sit about a 1/4" lower from the fuse. The idea here is to have that aircraft sit just a bit higher that depicted in the plans which will help with ground clearance using a 13" prop. The main struts will of course be a bit longer to match.

Chronos 333 who has already blazed the trail for me WRT converting his Aurora 60 to electric had the following update after mounting an APC 13 X 13N to his Hyperion 44045-10: 8S 3700mah/ 63amps/28.5Amps approx. 1750W. Factoring a conservative 85% efficiency, that's still approx 1500 watt output. Can't wait to try that!!
The link for those interested:
http://www.rcgroups.com/forums/showt...=4#post6575931

The local dealer did have the Hyperion mounting hardware for that motor in stock as seen in the one photo. Good quality although a bit heavy in my opinion.
Next step: installing the nosegear steering linkage and deciding exactly where I'll mount the nosegear retract servo.

RE: Aurora 60 Build Thread - Electric Power
 

Looks Great Jeff.
Go Skiing!!! :D:D Shoveling is for the neighbor kids looking to make a few bucks...(I'm too cheap and shovel my own, but not often here in central Virginia. I shoveled a lot more when I lived in Vermont. Skied a lot more, too:D)
Will B.

RE: Aurora 60 Build Thread - Electric Power
 

Hi Jeff,

Watch out for the tank floor!
I removed mine in order to place a micro servo on the top left corner to operate the nose gear... reliably...
I had enough of the occasional but very efficient nose brake!
You need some space to put your ESC relatively close to the motor while keeping ESC wires relatively short (possible back EMF issues if wires are too long).
I don't know if your ESC is "standard" sized like the first one I had (the one that caught fire 8S/50A) or if it is a larger one like the one I have now (large square with a heatsink type 12S/90A). A std one can be straped close or to the nose retract mechanism, whereas the big one will have to go below or right under your tank floor but keep in mind that having some airflow around the esc is a good thing so you may cut the floor to let the heatsink protude in this case.
In my case I had enough and ended up using tie-wraps to secure it.


Alex

RE: Aurora 60 Build Thread - Electric Power
 

Last but not least,

If you want to shave some weight off the beast, go buy yourself some light wheels at www.aircraft-world.com
They are the lightest/cheapest price/cheapest shipping (approx 2.5$) on these wheels.
Drill them slightly smaller than the landing gear diameter, and press fit them in... and here you have the lightest (0oz)/cheapest (0$) braking system on earth! (believe me it works well enough ... at least for me)
However, it is not as effective as the nose brake described in the previous post :D

Alex

RE: Aurora 60 Build Thread - Electric Power
 

My Hyperion 4045-10 motor arrived yesterday. Seems like a nice peice of kit although it's my first electric motor so who am I to say. Anyway, I thought some comparative data might be of interest so I took a photo of the Hyperion next to my YS 60 and I also weighed the two. Ref weight, it's interesting to note that the Hyperion with the prop adapter weighs exactly the same as the YS shown in the photo.......530 grams.

Next on the agenda will be to mount the spinner backplate to the prop adapter and then temporarily hang the entire motor assembly from the nosering. I'll then fabricate a motor mount which will bridge the 1.5" gap between "X" shaped aluminum mounting plate on the back of the motor and the plywood firewall which is positioned as per the original plans. Note that the electric motor is not as deep as your typical 60 2-stroke.

Will, I'll pass on the skiing advice as I'd rather stay home and build.

Chronos, I'll check those wheels out. As long as weight does not become a problem, I was hoping to use those gucci (and expensive) Tettra wheels that Central carries. We'll see I guess. Ref which ESC I'll run, I've pretty much decided on the Castle Creation 85A, HV (High Volt). Should do the trick and hopefully I won't have any fires to deal with as you did.

RE: Aurora 60 Build Thread - Electric Power
 

Pure methanol weighs .83 ounces per fluid ounce, or 6.63lbs per gallon. A lot of sixties use 12 or 14oz tanks. That's between 9.5 and 11.6 ounces in weight of fuel (oil does make the methanol heavier, so maybe add 1/4 ounce?).

Since I'm totally new to E-power, how much do the lipos for your Hyperion weigh?

And, I'm really enjoying your thread. Beautiful craftsmanship. So many outstanding builders in this forum, I can't say how much I've learned over the last year or so.

RE: Aurora 60 Build Thread - Electric Power
 

Raindave, thanks for the kind words. Sitting down and building again after a long layoff from the hobby has been a very pleasant experience. As you've read already, this electronic stuff is new to me as well but I'm muddling my way thru. It's all actually starting to make sense!
Ref your question, I'm planning to use 8 lipo cells in series (likely 2 packs of 4S in series). Advertised weights on average of a 4S, 3700mAh pack is approx 375 grams. Therefore 2 packs of 4S= 750 grams ~ 1.65 lbs. The ESC will weigh approx 3.5 oz.

So how does that compare with a .60 glow setup???? Motors weigh the same, the ESC is likely a tad heavier (guessing 1-2 oz) than an average header/silicon coupler and the lipo pack will be approx 1/3-1/2 lb heavier than the tank, fuel (14 oz) and pipe (5 oz) combined. Those figures are off the top of my head and maybe I'm omitting something from the equation. In any event, if there is a weight penalty converting to electric, I don't think it will be much in this case....so long as the AUW is 8.5lbs or less. I'd guess the Aurora starts to fly a bit "doggy" if heavier than that. Chronos claimed that his Aurora actually lost an ounce or 2 when he converted it to electric. If I can get anywhere near 1500W to the prop, it will be worth it. ----- "To the moon Alice!!"

RE: Aurora 60 Build Thread - Electric Power
 

From the little I know about electrics, you get full torque as soon as current touches the motor, and the bigger the load, the more amps they draw. That fact probably more than overcomes any slight weight penalty. E-power is Greek to me since I've never used it other than on small models. But, from what I've read you will get a much more constant torque throughout throttle settings. Although that consistency is paid for in careful heat management.

RE: Aurora 60 Build Thread - Electric Power
 

Remember to also factor in the header, retention bolts, tuned pipe, silicone coupler, soft mount, fuel tubing, stinger, your patented 12" of high tensile bail wire to tie aforementioned together... The eelctric will also have a few adders but I think it will come out ahead in the long run:D

RE: Aurora 60 Build Thread - Electric Power
 

All right Pete, the gloves are coming off!!! Even though I once had to resort to using bailwire to hold the entire pipe in place on my beat up Cosmos 60, I still take offence at the comment. Ya cut me deep on that one!

Anyhow, back to our program. After bolting the mounting backplate and prop adapter to the motor, I then mounted a 2.5" backplate from a Great Planes spinner. I used the Great Planes backplate even though the final spinner will be a Tru-Turn Standard, 2 Blade "Light" with 120 size blade slots. I contemplated using one of Tru-Turn's new anodized spinners but after looking at the available colours and comparing to the paint scheme I plan to apply, I decided to stick with the standard sliver finish although I did consider the black version. Speaking of finish, I'll likely copy the finish Steve Helms had on his pair of Auroras....with a few minor changes. The pattern of the Helms version is almost identical to the Naruke version but I like Steve's choice of colours better. I've included photos of both Helms' and Naruke's Auroras for reference.

The Great Planes spinner cone attaches via 2 small screws into the aluminum backplate. These 2 holes in the backplate were perfect for mounting/bolting the spinner backplate to the plywood nose ring and the ends of the maple hardwood motor mounts. If you're confused, consult the photos...should be self explanatory. Some of the gap between the spinner backplate and the front of the airplanes will be consumed with glass cloth and resin/paint when I apply the finish. When I originaly glued the nosering to the fuselage, I purposely angled the nosering to provide the required down and right thrust as per the plans. The result is the motor is now properly aligned and hanging in the engine compartment waiting for me to bridge the 1.5" gap to the plywood firewall. I don't want to simply use the metal dowels provided with the mounting kit as they are heavy and would result in a spindly and weak mount given the length required. As well, I want to be able to change the thrust angle of the motor if required without resorting to major surgery. I'll likely block something together to support a false firewall close to the "X" backplate. That false firewall will likely bolt into place and allow me to easily shift the mounting point verticaly and/or lateraly by simply substituting a replacement firewall. I'd much rather take extra time doing this right vice having the spinner misaligned with the front of the airplane if I have to change the thrust angle....and I suspect I will, a bit anyways.

One problem with leaving some of the pre-carved fuselage balsa blocks off the airplane is that some of the balsa mating surfaces get mushed a bit after repeatedly handling the fuselage. You can see small gaps in the balsa in some of the photos...... it's difficult to avoid. As soon as the internal mounting is squared away, I'll permanently glue the block at the front of the fuselage and finish carving the front end of the airplane near the spinner and cowling.