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70% Astro Hog scratchbuild - Finished!

Old 06-10-2010, 11:12 PM
  #26  
aramid
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Default Done!

I got my test flight in yesterday afternoon. The access hatch blew off as soon as the plane broke ground, so it'll be getting a few extra magnets; fortunately, this was the most dramatic part of the flight. The plane flies just exactly like an Astro Hog should - it just floats around and does the most magnificent lazy aerobatics. Vertical performance is nearly unlimited, but I'd like to get a bit more speed, so I might be trying a 9x9 prop (currently 10x7) in the next few days. Other than a few tweaks like that, I'm happy to call this one done!






There's no doubt which side is up in flight:


Excellent access to strap the battery onto its shelf:


Receiver and tail servos are reasonably accessible but out of the way:


Motor mount is just long bolts in some aluminum tubing:


Thanks for reading!
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Old 06-11-2010, 01:12 AM
  #27  
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Nice job.
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Old 06-11-2010, 03:29 AM
  #28  
Rabbitcreekok
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Nice looking Hog, Aramid. Glad the departure of the hatch did not cause any problems.
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Old 06-11-2010, 09:51 AM
  #29  
Sky Sharkster
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Default Good Job!

Nice work on the Hog, Aramid. Glad to hear it flies well, most Astro Hogs do. Great covering job, too!
Ron
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Old 06-12-2010, 06:05 PM
  #30  
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Great stuff, congratulations on your test flight.

At least you got your hatch back - there's two of mine in a wood atop a landfill in MD

Regards

Dereck
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Old 06-13-2010, 04:27 AM
  #31  
aramid
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Thanks for all the kind words!

There are a few tweaks remaining before the plane is really 100% complete. Obviously I need to add hatch magnets, but I also need to replace the bearings in my motor. I get plenty of power, but the motor feels a bit stiff to turn by hand, and the noise it makes is almost like a vacuum cleaner - definitely not what I want my plane to sound like. It's evidently a common problem with the TR-3536 motors, so I ordered a replacement set from rc-bearings.com. Should be back up to optimal in another week.

Again, thanks for reading!
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Old 07-07-2010, 04:04 PM
  #32  
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Hatch magnets! Mine are all in packing crates with the rest of our 'stuff' some 700 miles from where we'd really like them to be, but rumour has it, it will all come together.

I recall when these things first came out, and the efforts to track them down and buy them in realistic quantities - even the fastest builders amongst us don't really need them in thousands! Last week, we were doing Spousal Unit's favourite weekend occupation - shopping for 'house stuff' - and there in dear old 'Home Depot' are packs of ittybitty magnets, hatch retention, for the use of.

Have found retro-fitting hatch magnets to be real fun. When I build a hatch now, the magnets go in as soon as possible, well before the final top sheeting. The image is of my last OD - the magnet is on the rear vertical face of the hatch, rather than on the bottom. Though it is a sliding attachment rather than the usual 'vertical' one, it's held on fine through some gyrations. The hatch has the usual front tongue attachment, at the rear, it has short lengths of wood to prevent sideways movement.

D
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Old 07-07-2010, 04:29 PM
  #33  
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Fortunately, I had no trouble tripling the number of magnets on my hatch, and although I've only flown twice since then, it seems like they're going to hold.

I buy my magnets from SuperMagnetMan.net. I'm using 5mm/1.5mm disk magnets on the hatch, and small washers on the fuselage. If I did it again I would save myself the trouble and use direct magnet-to-magnet attachments.
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Old 07-27-2010, 03:15 AM
  #34  
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Aramid,

This is an absolutely beautiful plane. Not only do I love the solid balsa construction, but the finish is amazing!

I am working on a conversion project: vintage U-Control Nobler converted to an electric RC. I started a log of the progress here: http://www.rcgroups.com/forums/showthread.php?t=1271864

If I may, I have a few questions:
1. did the power set-up seem to sufice?
2. what did the weight without motor, batt, ecs end up at?
3. do you have video of flight?
4. hints/tips to achieve that caliber finish?

Thanks in advance!
mike
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Old 07-31-2010, 05:25 AM
  #35  
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Mike, thanks for the compliments!

The power system is perfect for the plane. It's running about 135 watts per pound with a pitch speed of about 60 MPH, which suits the style of the plane very nicely - it's not a racer and doesn't need a bunch of speed in reserve, but it's got enough power for vertical climbs and pretty much any conventional aerobatic maneuver.

Empty weight, without servos, receiver, motor, batteries, or speed controller is probably somewhere around 25 ounces. I can't tell you exactly because I don't recall doing a weigh-in before I added any electronics, but if I add up all the advertised weights and subtract them from the total it comes out to about 25.

I haven't gotten any video, but I've been meaning to. It's been difficult, because my club field has spent most of the summer underwater; I think it's finally getting back under control so I might have something for you in a week or so. I'll post it here if I do.

I'm glad you like the finish; unfortunately, I don't think I can give you much advice over the internet. I learned how to cover firsthand from my grandpa, and adopted the technique and some of the tricks he's picked up over many, many years. Perhaps the next time I build a plane I can put together a written guide detailing my approach, but short of that I'd barely even know where to begin. One way my technique differs from what I've seen others do is in my use of the heat gun - I barely use a covering iron except on perfectly flat surfaces. On open structure and curves, I'll simply tack one edge of the covering, then use the heat gun to pull the Monokote over the rest of the structure (wear thick cotton gloves to protect your hands from the heat). I get the iron out again to finish the seams and overlaps.

You have to be careful not to burn through the covering, so it actually works best with the flow restrictor on the gun fully open and the add-on nozzle in the trash, to keep the air temperature a bit lower. That's how I get the covering to pull tight over all the compound curves. It also helps that my Monokote is very old (some is older than I am), because the older formulation shrank more than the modern stuff. If you're buying new material from the hobby shop, use Coverite or Ultracote or Solarfilm or anything other than Monokote. The new stuff is an amazing pain to work with.
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Old 08-09-2010, 09:50 PM
  #36  
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Wow, what a beautiful build! I have a soft spot for low wing sport aircraft. I built a Great Planes electric Ryan STA (standoff scale) with what appear to be similar proportions. Do you think it would benefit at all from flaps?

Do you think it would be possible to get a copy of the PDF plans? I would like to get my hands on those puppies so I could add one of these to the fleet.

Thanks, and great work on that Hog!

Greg
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Old 08-10-2010, 12:27 AM
  #37  
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Thanks for the compliments!

Flaps would be fairly easy to add to the plane, and might be fun to play with, but are definitely not necessary. I've seen very few model planes which really needed them, of course, but they're fun to play with on warbirds and bush planes. On the Hog, especially if you build one as light as mine, it's completely overkill. This plane has extremely good low-speed manners, thanks to both its light weight and the bit of washout I built in.

I'll happily provide the plans to anyone who emails me asking for them. I've confirmed with Gene Rock, the creator, that they are free for non-commercial use; the only reason I won't post them freely is that Gene hasn't.
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Old 08-11-2010, 08:34 PM
  #38  
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Thanks a bunch for the plans! I will definatley use them in the coming months. I did find some really good plans from AMA for a 54inch Spacewalker designed by Laddie Mikulasko. I am going to build that first, and then this one. I have a soft spot for low wing, and classically designed sportsters.

Thanks again, this is going to be fun to get after!

Greg
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Old 08-25-2010, 03:49 AM
  #39  
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GORGEOUS plane! I need to get back to work on mine... and that blue and white color scheme is similar to what I want to paint my pocket rocket, at least I know it looks good!

Spit.
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Old 10-13-2010, 03:51 AM
  #40  
southdakotarcflyer
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Aramid: What a plane and you did a great job. My trainer recomened that plane for a good second plane. I currently fly a Nextstar and several blue foam planes that I have built. Playboy, and a flying W. I would love to build the Hog. Larry
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Old 10-13-2010, 07:53 PM
  #41  
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Thanks! Your trainer is right, the Hog would be an excellent second plane. It's relaxed and easy to fly, but has much better performance than a Nexstar.

Be aware, though, that if you build it light, it won't shrug off rough treatment like the trainer, and if you build it strong, it won't perform as well as it might. In any case, since just about everything is a compound curve, repairs will be more difficult.

I don't want to scare you away from the plane, because it's really very easy to fly. Just make sure you're able to safely and reliably land your Nexstar before you start flying the Hog, because the consequences of abuse are a bit harsher.
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Old 10-14-2010, 01:51 AM
  #42  
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Aramid. Once again thank you very much. I am sure I will be asking questions from time to time. I will not be building untill this winter sometime so maybe will have it done by spring. Larry
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Old 01-30-2011, 12:51 PM
  #43  
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Ohhhhh, I have to build one of these for sure ! Very nice, and excellent color choices.

Looks like I could use a Sig Four Star 20, do some minor shape changes and save a lot of cutting work. It is also in the same weight range. Yep, that Four Star has some really good promise as a basic basher kit. The OEM Four Star is a bit basic and chunky looking.
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Old 04-15-2011, 07:41 PM
  #44  
vonJaerschky
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Great job on your mini Hog. I also have had 2 big Sig Hogs, both powered with an OS FS-90 (their first .90 four stroke, with the pushrods in the back). The Hog is such a great flier, I always thought a smaller electric one would be great. My intent was to have something like a park flyer, so I scaled it to a 48" wing, and got rid of a lot of extra wood. Most of the fuselage is 1/8" sticks, and the wing uses 1/16" stringers where the leading edge sheeting of the wing normally goes. I also used barn door ailerons instead of strip ailerons. The model is covered now and I am going to test fly her this afternoon. All up weight with the battery is 19.5oz for a wing loading of 7.8oz sq/ft, so it should be a floater.
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Old 04-15-2011, 07:57 PM
  #45  
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That's a very nice-looking model you've got there. I'd love to see some pictures of the covering, but when you go to that kind of effort on a clean, open structure, sometimes they look just as good naked.

I'd considered doing something similar to that on mine, at least using stringers for the fuselage, but I ultimately decided to sheet it to keep the curves as smooth as possible. In retrospect, I should have sheeted with strips rather than sheets to help with the compound curves, though I doubt it would have changed the weight any.

You came in at essentially half the weight I did despite being pretty close to the same size. That's quite impressive, and should serve well as a parkflyer. You'll definitely feel any turbulence, though.
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Old 04-15-2011, 07:59 PM
  #46  
vonJaerschky
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Yeah, it'll get bumped around for sure. One of the great characteristics of the big Hogs is that they had enough mass to maintain momentum through maneuvers. My little one won't have that. I suspect it will be a clam weather park flyer, but should be just the thing for shooting touch and goes off a baseball diamond on a quiet evening.
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Old 04-17-2011, 09:50 PM
  #47  
idan678
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looking GREAT !!
great job !
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Old 05-14-2011, 08:29 PM
  #48  
ChrisW
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great plane. saved a lot of this post as a tut for myself for when i actually build one.
my old instructor let me buddy box his hog and i still remember how it 'rode around on rails'. beautiful plane that one.

i'm still a glow junky, and .60 size aircraft are easier for me to see... (eat your carrots kids)

however, living in an apartment doesn't give a lot of room. will be asking for a set of plans.
-Chris

PS any plans on making a reduced scale bipe?
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Old 05-15-2011, 05:01 AM
  #49  
aramid
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It's nice to get people interested in this great old plane. It was the first properly aerobatic RC model anyone ever made; although it flies more like a modern trainer than anything, it certainly looks a lot better than your typical high-wing box.

I don't think I'll be making a mini Hog Bipe. Partly, I don't really like biplanes. They look great but the glide is poor and they're a lot more work to build, transport, and assemble. If I do end up building a small biplane, though, it'll be a reduced Andrews Aeromaster. My grandpa has the original plans sitting around somewhere, and it would be fun to scale down the outlines and create my own structure.
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Old 05-17-2011, 10:59 PM
  #50  
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Aeromaster - now there's a classic! I actually bought a kit off a clubmate, who'd had it for years. It sat around my shop a year or two - was still coming home smelling funny after flying then - and then it got moved on.

Bipes can be a pain. I did a couple years back in England. One was extremely 'minimal', based on balsa being 36" long and its Enya 40 open rocker fourbanger not being very powerful. The other was a full depth fuselage back stagger job, again based on 36" wood - I have high standards of exactitude - and a 20 squealer.

The great thing about the latter was a minimum of wire bending!

My IMAA legal Smog Hog - 9/14ths full scale - was fun in the day, though it rotted off the back of its 19 diesel lump. If I can ever reconcile its looks with a taildragger UC, I'd love to get stuck into a CAD file entitled K'E'os one day. Guess what it's based on? It just doesn't look right without the trike gear, but that wouldn't go well with the grass fields I'd be flying off around here.

Looks like this Hog-let has settled down to a long stay in the fleet, good luck with her

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