Aurora 60 Build Thread - Electric Power (Full Version)

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Bootalini -> Aurora 60 Build Thread - Electric Power (11/10/2006 7:12 PM)

Greetings Aurora lovers,
I'm an ex-FAI pattern flyer whose been out of RC for approx 8 years. The last while I've been following the progress made on the electric power side of things and I've finally decided to take the plunge and build something "old school" (but fun) and go out and bore holes in the sky. Who knows....maybe I'll eventually catch the competitive bug again.

Why the Aurora? I've been a long-time fan of this design although I never had one. PTXMan in Calgary gave me a set of plans about 10+ years ago but I never did get around to building it. I did however build and fly Naruke's predecessor airplane, the Cosmos and really enjoyed it....that thing was a ballistic flying bomb!! Webra Race .61 (with a Perry pump embedded withing the backplate) up front coupled to a Hatori pipe.
My Aurora will be built 99% as per my MK plans (fuse/wing profile, wing area, etc) although I'm going to incorporate a few different things that won't be so obvious at a glance. I'll be going the plug-in wing and stab route vice the standard 1 piece that the original design has. After flying 2 Piorun Eclipses and then 2 of Greg Marsden's Legend IIIs (both designs have plug-in wings/stabs), I simply find it easier to dial-in all flying surfaces (wings and stabs) both during the building/alignment stages and more importantly later during the flight trimming stage. Ref wing airfoil, I'll also be using a slightly thinner NACA airfoil with the high point 35% back. I'll incorporate the normal wing fillets on the fuse which will hide the fact that the wings are plug-in. I'm still undecided about trike or tail-dragger. Trike config is of course prefered from a purist point of view but I'm having trouble locating suitable mechanical trike retracts......can anyone help here?...a set of MKs would be ideal.
I obtained my Aurora cowling and canopy from Singapore Hobbies. Great service from Ronald, their sales rep. The parts arrived in less than 2 weeks! Ron mentioned that my Aurora 60 cowling was their last one and that they will not be receiving any more. I hope he's incorrect on that one.
As you can see from the attached photos, I'm well on my way on the project. The toughest part thus far was reproducing the required accurate ply and lite-ply bulkheads. My MK plans have sufficient fuse cross section views but about half of them don't correspond with the position along the fuse where the bulkheads reside. I was left with having to carefully study the plans, extrapolate measurements etc...I'm sure most of you have experienced the same thing scratch building. Another complicating factor was the fact that I had covered the plans in map-tack years ago with some resultant winkles here and there. Again, I was having to take my time. If anyone has a good set of Aurora plans (or a copy) they'd part with, I'll gladly pay for them.

My fuselage jig was simple in design but sufficiently effective. This coupled with my using a pool table as my work bench top ensured a true reference building surface. That same table top will be very handy when I later frame the flying surface to the fuse. I will be using good old fashioned squares and rulers for the alignment process, vice incidence measuring tools/meters which I find difficult to get the same readings from them twice in a row.

Anyway, I won't be nearly as detailed in this thread as 8178's outstanding Blue Angel build (I'm too lazy) but hope you'll enjoy it anyway.

Jeff L




rcguy! -> RE: Aurora 60 Build Thread - Electric Power (11/10/2006 7:36 PM)

What electric power are you planning?

Dave



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/10/2006 9:01 PM)

Dave, right now, it's a toss-up between the Hyperion 4045-10 and a Neu "ork" 19XX series. Chronos 333 has a post on the RC Groups newsgroup (Gas-Electric Conversion) where he has also converted an Aurora 60 using the Hyperion. His #s are:

Hyp 4045-10
TMM 5024 ESC
8s Lipo (3700mAh)
APC 14 X 12E (55Amps)
APC 14 X 14 (57A)

http://www.rcgroups.com/forums/showthread.php?t=471610

He likened the performance to fitting a YS 120 to the front minus the weight penalty...lots of power! He seems pleased although the big issue with the setup is poor ground clearance on grass. Those older trike equiped pattern ships were meant for 11 or 12" props.

I'm very pleased with my fuselage thus far. She's perfectly straight with everything nice and square. Ref weight, I'm at 360 grams (.75 lb) as seen in the attached photo. I was hoping for lighter but at least it's very stiff in the wing attachment area. I'll try to shave grams when I carve and hollow the top and bottom blocks.

Jeff L



rcguy! -> RE: Aurora 60 Build Thread - Electric Power (11/10/2006 10:27 PM)

Jeff,
Thanks fore the speedy reply. I'll check that thread out. Looking for a "pattern" project this winter for electric. I have the Compensator planset from AMA. Also Kaos and Super Kaos. I'm a pattern flier from the late 70's early 80's in Ohio.

Your build looks good! Keep her straight and light!

Dave



8178 -> RE: Aurora 60 Build Thread - Electric Power (11/11/2006 1:15 AM)

Hi Jeff,

I’m really looking forward to following your Aurora build! Thanks for taking the time to share with us. Your work looks excellent and the construction of the parts looks a lot like the technique MK used in the Blue Angel kit!

This classic pattern forum is getting to be pretty darn awesome.



McLaughlinRP -> RE: Aurora 60 Build Thread - Electric Power (11/11/2006 8:43 AM)

Congratulations! The Aurora was my favorite plane of all time. "Back in the day", I built the MK kit which was clearly the best kit I have ever seen. I had a lot of fun with it and I'm sure you will too. Consider the BPA...excellent candidate.

I still have the MK nosegear I used in that plane in 1989. It is the only airplane related thing I saved during my 15 year absence from flying! Funny the things we save...I probably will not use it again so if you are interested in it shoot me an email. I used Supras for the mains and I have recently acquired a set of those too.

Let me know and good luck! I look forward to following your progress.

Ryan McLaughlin



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/11/2006 3:41 PM)

Ryan, just sent you a PM.

Jeff L



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/12/2006 1:05 AM)

Latest progress as I just finished roughing-out the front-top and rear-bottom blocks which will be "tacked" to the fuselage prior to carving the general fuse shape. Sure wish I had a band saw available.....cutting thick blocks accurately can be tough when all you have available is a small motorized scroll saw! It took a while but the blocks have the proper shape according to the plans. I've included a photo with the bottom cowl in place to depict the rough outline of the bottom of the fuse.

It should be noted that in some areas, I've simplified the construction just a bit. After studying the plans carefully prior to starting the project I came to the conclusion that some areas of the construction were overly elaborate and thus difficult to replicate. Don't get me wrong though, MK kits are first class. And despite the internal mods, my intention is to maintain fidelity with respect to lines and shape.

Next step is to produce the fuse shape templates and start carving/hollowing.

Jeff L



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/12/2006 8:43 PM)

I just finished fabricating and gluing both top side pieces of the fuselage. I used 1/2" thick light balsa (approx 6 lb density) for those 2 pieces as I knew they would be difficult to trim given the required angles and curves and the fact that I would not be able to hollow these from the inside afterward. They turned out as good as can be expected with only a few minor gaps in a few spots. The next step is to trim the tops of those shoulder pieces flush with the tops of the fuse bulkheads and then add the top "cap". The top of the Aurora fuse has a constant curve/slope all the way to the vertical stab which is necessitating my having to take my time and be careful.

I also cut the fuse outline templates from some spare 1/8" acid free picture frame backing board that I had lying around. That stuff has a special foam core that is perfect for the job. It's fairly stiff yet easy to cut and sand to shape.

Well, that's it's for now. I'll soon be making a mess of my work area from balsa shavings and dust!

Jeff L



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/15/2006 6:33 AM)

After shaping the proper outlines of the top and bottom fuse blocks, I then tacked them in place using only a few drops of thick CA each. After I'm done carving and rough-finishing the outer fuselage, I'll then pop those blocks off and hollow them from the inside. It's a laborious but rewarding process as the fuselage slowly takes it's familiar shape while maintaining a reasonable weight.
The one photo shows the 5mm thin ply strips embedded in both fuse sides which are nescessary for mounting and holding the lower cowling in place.
Even though I'll be using electric power for this project, I installed a flexi Nyrod throttle cable in case a glow motor should one day make it's way into the nose. That's all for now.

Jeff L



Roary m -> RE: Aurora 60 Build Thread - Electric Power (11/15/2006 8:21 AM)

I have seen electric pattern ships at our field and they fly fantastic, but isn't putting electric on an o.o.p. Aurora 60 sortof blasphemous?



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/15/2006 7:36 PM)

Roary, interesting comment which begs opening another can of worms. At the risk of doing that.........my thoughts on the subject:
-1600Watts (to the motor) is what I'm planning. Given an estimated 8 lb aircraft weight and resultant 200w/lb ratio, that should be the equivalent to an absolutely fire breathing .60 2 stroke equivalent performance. A fair statement is that all pattern ships, old or new design, simply fly better with an overage of power. My goal here is to build one of the faster pattern airplanes capable of still flying the early FAI style turnarould well....and have excess power which should help. It's a cool design as well.
-I've may have already offended some Aurora "purists" out there by virtue of modifying a few things (plug-in wings and stab, slightly thinner airfoil, etc). At the end of the day, it will still look and smell like an Aurora. Might even fly better? Who knows.
-Having read about the Senior Pattern Association which I think is pretty darn cool, I noticed that they allow 4-strokes on the old designs. I don't know about you but I attended many pattern contests in the 70s and I don't remember 4 strokes being on the front of those older designs. There may have been the odd one but the 4 bangers of the era were relatively anemic and heavy compared to 2 strokes. I think the SPA is correct to allow certain changes.....it's about keeping the balance between retro/current times/ parts availability, etc. And that's my point: in my opinion, electrics will only gain popularity in the future and the type of conversion I'm performing may become common.

Having said all that, I'm eyeballing a Kyosho Oxalis 50 ARF (for electric power) as a potential Christmas gift. Best of both worlds!

Jeff L



rainedave -> RE: Aurora 60 Build Thread - Electric Power (11/15/2006 7:48 PM)

Jeff, great job on the build. How do you plan to finish it?

A while back I opened my calculator and crunched a whole bunch of numbers based on the current electric systems pricing. I took into account that buying a $350 LiPo pack(s) is similar to buying a few cases of glow fuel up front. In the end I found that given the current prices of electric components, you can stay even with glow power up through .40-size planes. After that, electric becomes increasingly more expensive than glow (even taking into account the up-front investment factor). I do think that over the next few years electric prices will come down and it will be more feasible to power .60 and 1.20 size planes with E-power.



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/15/2006 10:01 PM)

Raindave, I would prefer to apply a cloth/base coat/clear coat paint finish vice Monokote but I'm going to wait and see what the weight of the airframe is first. RTF, I really want to stay 8lbs or below. I've have however used Monokote on most of my past airplanes and if carefully applied, it looks good. But nothing compares to a nice paint finish IMO!

Ref glow vs electric cost, I agree with your comments although I've not looked at the issue to the degree you have. It's going to cost me roughly $1000 just to power this puppy which includes an extra 8S battery pack.
Motor = $150
ECS= $200
Lipo 8S 3700 (X 2) = $700
On the plus side, no messy oil residue, expensive 25% nitro fuel, pricy glow plugs, bearings (which I had to replace often), etc.

To be honest, the rapidly improving electric aspect has been the catalyst to my getting back into RC airplanes. I'm looking forward to getting airborne again.

Jeff L



rainedave -> RE: Aurora 60 Build Thread - Electric Power (11/16/2006 12:29 AM)

Please paint it!!! I'm painting my UFO with Brodak dope and I'm very glad I chose to. Dope can actually come out about the same as Monokote, or even lighter. I covered my wings with Koverall and dope and they are turning out nice. I think I've added maybe 1 1/2oz in dope so far.



Roary m -> RE: Aurora 60 Build Thread - Electric Power (11/16/2006 8:24 AM)

Yes, Boot, that was the purist coming out there. I am convinced the ship will perform at least as well as it did in the two stroke world and for the skeptics, they really have to witness how well the plane performs. One of the guys at our field has a Showtime with I think a Hacker motor in front; he just takes it off and points it straight up, gone. I just wish Singapore hobbies would reconsider on some of the vintage designs by MK, but commerce marches on.



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/17/2006 4:10 AM)

Finished the preliminary carving. Next step is to continue shaving balsa until the final shape is achieved using the earlier mentioned templates as guides. Is she starting to look familiar?

I'd like to get started on the wings and stab shortly but Kevin at Matney models has not returned my correspondence in close to 3 weeks. He had agreed to do the CNC foam cutting for me. Anyone spoken with him the last while?

Jeff L



flywilly -> RE: Aurora 60 Build Thread - Electric Power (11/17/2006 5:44 AM)

Great thread, Jeff!!
I'm flying an Aurora right now (well, not RIGHT NOW[:D]) that was saved from a swap shop (partially built and missing a few things) with a Hanno Special. Flies great. Mine is all monokote mostly because it is much easier to apply (I can go down to my shop and monokote for 30minutes or 2 hours - painting is geared towards a few major productions, though I love the results my family is not fond of the 'stench').
Thinner wings are going to make your Aurora even more slippery on landing.
Keep up the great work. Can't wait for the flight report!
Will B.



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/17/2006 7:51 AM)

Just finished shaping the fuselage to the point where I can now detach the top and bottom blocks. Next is the tedious job of hollowing those blocks before re-attaching them and applying the finishing touches to the fuse.
A few things yet to do include the installation of the internal antenna guide, the cable guides for the pull-pull rudder, and finishing the cowling so I can properly mount it to the fuse bottom which is the only way to truly determine to what point I can trim the lower fuselage edge where it mates with the cowling edge.
As well, given that no more Aurora 60 cowlings are available (supposedly), I might rip a quick mold from the original just in case I need a spare in the future. All it takes is 1 belly landing in the rough to wreck the fragile cowl.

Jeff L



mmattockx -> RE: Aurora 60 Build Thread - Electric Power (11/17/2006 8:18 AM)


quote:

ORIGINAL: Bootalini

Just finished shaping the fuselage to the point where I can now detach the top and bottom blocks.

Jeff L


Mmmm, balsa! I love watching these build threads of scratch built, all-wood airframes. Just gorgeous...[:D]


Mark



8178 -> RE: Aurora 60 Build Thread - Electric Power (11/17/2006 5:47 PM)

Jeff,

Your thread is great. I’m enjoying seeing another MK design being built from plans.

Taking a mold of the fuselage cowl and canopy would be a great idea although the canopy requires special materials. There might be someone willing to produce parts from your molds so that the Aurora 60 can live on.

Take a look at the router tool I used to carve out the parts on the Blue Angel. I was easy to use and control the cutting process.



ptxman -> RE: Aurora 60 Build Thread - Electric Power (11/18/2006 8:22 PM)

You HAVE been a busy wood beaver lately. Looking good Boots!



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/19/2006 7:35 PM)

Rough hollowing-out of the blocks. A little more sanding and they're ready to glue back on. If you look closely, you can see where some small bits of the balsa of the main fuselage stuck to a few balsa blocks when I pulled them off. No big deal as I'll have to apply micro balloons anyway during the final finishing stages. The key of course is to keep the filler to a minimum.

I still have a few items to complete before I permanently glue the top and bottom blocks back on. I called Central Hobbies yesterday and ordered their new carbon rod Dual Elevator Pushrod System and a Gator Adj Stab Kit which I want to install first. Central's all out of Gator Plug-In Wing Adjusters and Gator Wing Tubes though. TNT Landing Gear shows as having wing tubes/sockets available but does anyone know where I can get wing adjusters for the wing panel pins??

8178, I hear ref a plug but I don't think my fuse is the best for such an endeavor. I believe that a glass kit of the Aurora should be engineered around the standard 1 piece wing and not plug-in wings. I'm betting the "pattern classic" fans out there will agree. Did I read somewhere that Dan at Carolina Custom A/C had the Aurora 60 on his list of kits to produce? Having said all that, I think a mold from my original untouched cowling is a must given that they're no longer available. I can do it myself (limited mold making experience) but anyone out there comfortable with the process is welcome to take it on. Canopies are still available from Singapore Hobbies. Great service from them but the shipping is a bit steep for small parts....understandable I guess given the location.

Jeff L



8178 -> RE: Aurora 60 Build Thread - Electric Power (11/19/2006 9:03 PM)

Jeff,

It sure is fun making all the balsa shavings isn’t it!

I was referring to just the cowling and canopy and not the complete fuselage. It would be great if there was a mold of the cowling and it is good that the canopy is still available from Singapore Hobbies.

I know there are a few people that have bought Blue Angel canopies, wing cores and plans from Dan at Carolina Custom Aircraft that came out of my build process. It is pretty neat that there are people on RCU that are willing to share plans and parts so that these wonderful designs can be continued to be built even though the kits are out of production.



Bootalini -> RE: Aurora 60 Build Thread - Electric Power (11/21/2006 10:39 PM)

Raindave, I guess I need to pay closer attention when I read people's posts. And yes, building this project has been fun and has also made me aware of the all the great folks and goodwill out there. Ryan McLaughlin has graciously donated an MK nosegear and Supra mains to the project. That same comaraderie seems typical as I scour all these classic pattern threads.

My build continues with the fabrication and mounting of the vertical fin. I have the rudder left to build but I'll soon be ready to tack the pieces together, temporarily hinge and mount the fin/rudder, rough shape the outside and then break the whole unit loose again until I complete installation of the elevator pushrod system inside the fuse. At a glance, things line up fairly well although I'm going to take my time to ensure the fin is absolute square to the fuse and aligned with the fuse's longitudinal axis. Any errors here make it difficult to accurately trim the airplane later. I'm going to use a pull-pull system for the rudder.

Ref the wings/stab, I'm at a stand still on that aspect of the project. Kevin Matney (Matney Models) still has not got back to me. As a result, on Saturday I sent the required info to flyingfoam.com looking for a quote. Hopefully I hear from them soon. Back-up plan is for PTX-Man to plot the built-up wing and stab for me using the Profili program. We'll see.

Jeff L



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