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8178, I never looked at the 2 photos that close but I think you're right! And significant differences at that. Not only does Naruke's canopy start further back, it seems smaller both in length and height, and the high point looks further back along the fuse as well.
Anyone out there know if Naruke had several prototypes of the Aurora? Perhaps the design underwent a bit of tweaking along the way. I'm assuming that MK would make a point of being accurate when kitting a design....?? To be honest though, I much prefer the front end looks of Helms' Aurora. A point to ponder is that Steve had his 2 airplanes built for him by craftsmen in Japan I believe. We can't necessarily assume that they built them from MK kits.
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You're right! I've seen both of those photos before, and never noticed the difference up until now. That's a good 4" difference. If we could somehow get our hands on these "Radio Technique" plans, it might contain some revelations.
Jeff, First, on the weight issue... you can save a lot by using a UBEC. Medusaresearch is providing some hi current/5A continuous/6 volt Ubec... that's the one you need. Second, it is unfair to compare your setup to a 60-2 stroke. Your power plant with a 14X14 is closer to a 120-4S powerwise ... except that it is a lot lighter I did a power/weight comparison in our club's journal... but it is in french. Here is the link: (look at page 8) http://www.c2vm.org/buse/C2VM%20-%20La%20Buse%20bavardeuse%20-%20Avril%202006.pdf
Best regards,
Alex
< Message edited by chronos333 -- 1/7/2007 2:42:05 PM >
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quote:
ORIGINAL: Bootalini
8178, I never looked at the 2 photos that close but I think you're right! And significant differences at that. Not only does Naruke's canopy start further back, it seems smaller both in length and height, and the high point looks further back along the fuse as well.
Anyone out there know if Naruke had several prototypes of the Aurora? Perhaps the design underwent a bit of tweaking along the way. I'm assuming that MK would make a point of being accurate when kitting a design....?? To be honest though, I much prefer the front end looks of Helms' Aurora. A point to ponder is that Steve had his 2 airplanes built for him by craftsmen in Japan I believe. We can't necessarily assume that they built them from MK kits.
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Alex, I was under the impression that a BEC was not yet available for the higher volt/power application that we're discussing here. I'll check into that as you're right...I could save the weight of the airborne radio pack. I wonder if adding a BEC to an ESC increases it's weight?
Ref the newsletter, that's a very informative E vs Glow comparison that should open a few eyes among the 60 size pattern crowd. For those of you that are French impaired, I think you can easily interpolate all the page 8 info except the last para "en termes de prix" which means "in terms of price" - Alex states that the price of the 2 setups is roughly the same except for the fact that because of the present charging rate limitation of lipos, you have to go out and purchase at least 1 spare lipo pack unless you want to bring a shaving kit with you to the flying field.
An extra 8S pack (3700 mAh) will run at least $300 but if you consider that a properly maintained pack should last 200 flights, that translates into a fair bit of flying. Compare that to the price of 15% glow fuel X 12-14oz/flight, expensive glow plugs etc, it's not so bad. I'm also told that if you don't over-amp these electric motors, they have a lonnnnnggggg life. When I was flying seriously, I never got much more than a season out of a piston/liner including the shadel ones, and I changed both bearings at least twice a year as well........I think you get the idea. For the glow guys (including me) the pain up front is buying the charger, discharger etc......and we're getting older and becoming resistant to change.......wink, wink.
My cores arrived late yesterday. Mike Hester (of Black Magic fame) custom cut them for me including boring the holes for the wing and stab tubes. Mike did a great job and I owe him big thanks and my strongest endorsement for any of you that may deal with him in the future. Keep in mind that I'm picky and my last 4 airplanes were kitted by Henry Piorun and Greg Marsden, both of which are know for their excellent craftsmanship. Thanks Mike!
Wow Jeff, you were eating more bearings than I was! Maybe because nitro was cheaper in north-america. When I was flying seriously I set of bearing per season was OK... but they were quite noisy at the end of the season! (I was runing 5 to 10% nitro).
Now about the BEC, you have 2 kinds of BEC's: - Linear Becs (like the ones on low voltage esc & some voltage regulators): avoid them if using more than 3S lipo and 2 servos! They are not efficient as they dissipate the excess energy in heat. Thus their power handling capacity is limited by their heat dissipation capacity. I almost lost my hotliner by overeating the ESC's bec. - Switching BECs (UBEC/SBECS/etc...) they are the way to go. However, most are limited to 5 or 6S lipo input and 3amps continuous 5amps peak. Which is OK for 6/7 std servos (=3-4 digis or 3-4 high torques) but I like to have some headroom that's why a 5 amps continuous is great. Why 6V? Because I use micro servos! For this season my Ubec is out as I need weight (rx pack) in the tail to fine tune my cog (I can't put the 8S anymore in the back)
For the charger, go buy yourself an Astro 109D and some good lipo balancer... the cheapest Watt/$. The current market price for a 109D in good shape shipped conus is around 90$ For the connectors, at these power levels don't trust sermos/asto/deans and the likes go for gold bullet 4 or 5mm, if you have troubles finding some, let me know... I buy them in bulk.
Last but not least about the Glow Vs E planes. In terms of weight, a glow plane tends to get heavier as the glow fuel soaks & roten the wood! In terms of airplane's life expectancy, glow engines causes a lot of vibration (on top of being unreliable) which affects reliability of both the airframe and its electrical components. In terms of power and flight times, the e-engine will give the same amount of power no matter what the weather is, no on the field tuning necessary...just plug/play/unplug/go home! e-hp are real hp, not paper hp in ideal conditions at 17K rpm.
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I managed a few hours in the basement today with the NFL playoffs in the background. The photos show my progression from laying things out on the bottom of each core to building the false ribs which will support both the wing tube and the main gear mounts. I'll cover this phase in detail for the benefit of those out there who have never built plug-in wings. For those experienced in this area, it's likely old hat. If you look closely, you'll notice that the tube holes on the false ribs are off center quite a bit. That's because Mike Hester purposely offset the tube hole vertically in the cores to obtain acceptable tube depth (8" in the thinner than stock wing panels. By the way, the chosen airfoil is a NACA 63 012A (12% with high point at 35% of the chord) which is a notably thinner airfoil than the original.
Each wing panel will use 2 ribs of 3mm lite ply in the area of the landing gear. In addition, the inner root of the wing will also be capped with a lite ply rib (full length of the chord) which will support wing tube where it first enters the wing panel. The wing panel pins will also be glued to the inner ribs. I've used this set-up on my last 4 airplanes and I've never had anything come loose or get "soft". As a gear attachment point, it's also a very robust setup for those of you that have ever torn a main gear(s) assembly right out of the foam during a rough landing.
It's important that when you cut the wing tube holes in the ribs that the holes fit the tube with zero play otherwise you'll have to use excess glue when installing the rib assembly to ensure that there are no gaps between the tube and supporting ribs. Last thing you want is for the tube assembly to have play within the wing core.......that would be a minor nightmare trying to repair later. I still have to drill holes at the back of each false rib to accomodate the aileron servo lead hole/tube which runs from the wing root to the servo boxes. I'll also fabricate the main gear mounts and glue them to the false ribs. Once all that's done, it will be time to glue the wing tube outer sheath and the entire false rib assembly into the cores. I normally use epoxy for the wing tube and silicon for the false ribs.
If the 35 or 40 Mhz band is free for use for rc airplanes, acteurope.de is offering a nice alternative. No bec needed. You can switch the receiver and servo's directly to two lipo cells. Now, part of the ACT receivers have a seperate bus for plugging them onto the current, and this bus can handle up to 15A. The big servo is offering : Stellkraft 305NCM bei 7,5V = 30,5Kg power Haltekraft bei 7,5V -> 385Ncm = 38,5Kg Holding power
They have a smaller version as well, and they do work on lower tension as well.
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I was a bit short of building time this week but I did manage to get some pre-sheeting prep done on the wing cores.
First, I cut and fit the hardwood gear mounts to the false ribs. I cut the false rib rectangular slots carefully so as to attain a nice snug fit which when combined with a bit of glasswork will make for a strong setup. You'll notice that the forward mounting gear beam is sitting a bit deeper in the false rib in order to maintain the gear hanging vetically with the gear down. Let me explain......the main gear positioning on this Aurora is further back than on the original plans due to the fact that I now have to account for a wing tube. The thinner than normal wing is not helping either. The net result is that the mains are mounted "non-level" behing the high point of the wing camber.
Next on the "to do" list was cutting a path for each wing servo lead. Central was all out of Gator tubes for this so I defaulted to plan B. The photos illustrate better than I can explain but this method worked well. Simply start by cutting a vertical slot of approx 1/8" X 1/2" deep with a sharp X-Acto and then let the Dremel do the rest. This method actually leaves a relatively clean setup.
Next up is glassing the beam mounts to the false ribs, installing the whole assembly into the wing including the wing tube, and then gluing/sanding the balsa skins. I hope to have the wings sheeted by mid-week.
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Joined: 9/5/2006 From: Ottawa,
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The last steps prior to the installing the false rib/gear mount assemblies was the reeinforcing of the gear mounts with a bit of glass cloth and the capping of the tube sleeve ends. I didn't have to use much light cloth and Zap to solidly anchor the mounts and that's good because I didn't want to increase the width of the ribs by a substantial amount. After capping the carbon fibre sleeve ends with lite ply, I was then ready to glue the whole mess into place.
I layed pieces of Saran wrap in the foam 'saddles' as there would inevitably be some epoxy and/or silicon leakage in the gluing/setup process. I started by coating both sides of the false ribs with RTV silicon and then press fitting the entire assemblies into the cores. After cleaning up the excess silicon that oozed out, I then mixed a small batch of 3 hour epoxy, coated the tubes and inserted them into the cores to the desired depth. Speaking of tube depth, the tubes/sleeves are embedded 8.5" into each core which equates to each tube running 1/8" past the outer rib in each wing panel.
The last step was ensuring the alignment and squareness of the cores relative to each other and the tube. Everything looks to be bang-on but I should mention that I tried numerous dry-fits before going ahead with the glue and silicon. WRT alignment, it didn't have to break a sweat really as Mike Hester did a first class job of cutting the cores and boring the holes accurately....and that's the key!!
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RE: Aurora 60 Build Thread - Electric Power - 
in the thinner than stock wing panels. By the way, the chosen airfoil is a NACA 63 012A (12% with high point at 35% of the chord) which is a notably thinner airfoil than the original. 
