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Sig Astro Hog "Engine recomendations

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Old 10-17-2005, 09:36 AM
  #1
lalaland
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Default Sig Astro Hog "Engine recomendations

In the process of building a Sig Astro Hog.

I want an engine to get me off the grassy runway. Planning on putting an O.S. FL .70 4-Stroke on it. Will that be enough to get me off the grass? Grass is usually about 2 1/2 inches high. I also plan on doing some nice manuvers with it.

Also, on the tail dragger verson, I noticed pics of astro hogs with "aluminum" main landing gear rather than the wire gear built in the wing. Is there a reason for that? I'm not a professional builder.

Need all the help I can get.

Big Dan

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Old 10-17-2005, 12:09 PM
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Default RE: Sig Astro Hog "Engine recomendations

Hello Big Dan; There has been a lot of controversy about that FL 70 lately, with the concensus being that OS Cheaped out on it. If your happy with OS, then perhaps an older FS 70 Surpass would serve you better, or a Saito or Magnum. I have a Surp 70 that I have had for years and am happy with, but I think OS have been left behind by other engine makers. My choice would be a Saito 72.

We have an astro hog at our field running an old Merco 61, plenty of power, but too noisy.

The aluminum gear you saw on the tail dragger was probably easier to mount on the fuse then re-engineering the wing mounted tricycle gear, as the gear has to be moved forward for tail dragging, I have had to do this on a few planes to convert from tricycle gear.
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Old 10-17-2005, 12:13 PM
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Default RE: Sig Astro Hog "Engine recomendations

the plans show how to mount the landing gear more forward in the wing for the tail dragger setup. It's no more difficult than the trike version. I think you may have all of the necessary materials in the kit to build it either as a tail dragger or a trike.

I've been running a K&B .65 (taildragger setup) on mine for years. Gets off grass with no problems. I don't know much about 4 strokes but I think I would look for something a little larger than a .70
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Old 10-17-2005, 12:49 PM
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Default RE: Sig Astro Hog "Engine recomendations

If it were me, I'd go with an OS 91 Surpass
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Old 10-17-2005, 04:20 PM
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Default RE: Sig Astro Hog "Engine recomendations

Saito 100 would do nicely IMO.
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Old 10-17-2005, 04:40 PM
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Default RE: Sig Astro Hog "Engine recomendations

i have one in building that is going to get a saito .91
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Old 10-17-2005, 05:27 PM
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Default RE: Sig Astro Hog "Engine recomendations

The Hog in my avatar has an OS 70 Surpass I and a 13x6 prop. With 10% nitro, on grass, it takes off easily at half throttle. My plane weighs 7 pounds 14 ounces according to a fish scale. My plane is a tail dragger, originally built with the gear in the wing. The 3rd landing missed the runway and the tall grass broke a gear block loose. After I fixedthe wing I mounted a Dubro fiberglass gear in front of the wing saddle so I wouldn't damage the wing again on a rough landing. I cut in a piece of 1/4" aircraft ply on the bottom of the fuselage and ran a strip of fiberglass cloth from the firewall to the wing saddle for support. I doubt this gear block will ever get pulled off.
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Old 10-17-2005, 11:30 PM
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Default RE: Sig Astro Hog "Engine recomendations

Thanks for all the help.

Upon further review I've decided to stick an O.S. 61 FX 2-stroke on it. I want enough power to get me off the ground easily. I can always throttle back once airborne. I have read too many threads where 4-strokers require lots of maintainence and I'm not much of a maintainence man when it comes to replacing parts. I've never had any trouble with O.S. 2-stroke FX engines and I like the power they produce and easy start ups.

I also decided to build the taildragger verson as plans call for. If the main gear tears off I will replace it with the aluminum or fiberglass gear.

Once again, thanks.

Big Dan "Da RC Dummy"
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Old 10-18-2005, 08:23 PM
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Default RE: Sig Astro Hog "Engine recomendations

I have a Magnum 80 4 stroke in my Astro Hog, it has plenty of power so I'm sure the 70 would be fine. I built mine as a tail dragger, I had a problem with the original wire gear wanting to rotate slightly in the wing blocks. This made for a few nose overs when taxiing. Just make sure it is good and tight in the landing gear block grooves and it should work fine. You'll definitely enjoy this plane
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Old 10-19-2005, 07:21 AM
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Default RE: Sig Astro Hog "Engine recomendations

I have an OS 70 Surpass in mine, with taildragger configuation. This engine is more than enough power for the plane. I fly off grass as well. This is my second Astro Hog (scratch built). I did move the landing gear block a little bit forward in the wing because the first one was having nose over problems. This plane is designed to fly on the wing and does not need a huge engine to fly well or get it off the grass.
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Old 10-19-2005, 08:44 AM
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Default RE: Sig Astro Hog "Engine recomendations

Dan, Here's a pic of my "Hog", And also in my Avitar. I built mine as a tail dragger (Wing mounted gear) because that was the way the original Hogs were designed to be back in the late fifties. It is sacralege to install a Tri-gear on this old design !!
My Hog flys beautifully with just a Thunder Tiger .61 for power...In the "Old Days" all they used were .35-.45 sized engines. Mine performs most of the basic maneuvers... just a little slower ! A real joy to fly ! Like they say..."Nothing Flys Like A Hog " !!

Enjoy your Hog !
Ugo
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Old 10-19-2005, 08:24 PM
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Default RE: Sig Astro Hog "Engine recomendations

[8D]Beautiful aircraft, great job. I like the good looking
and "easy to see in the sky" color scheme.

I plan on getting this kit this fall. It will be the third Hog
that I have built over the years. It will be powered with
an OS .70 FS II.
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Old 10-19-2005, 09:00 PM
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wilinfla
 
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Default RE: Sig Astro Hog "Engine recomendations

I couldn't resist posting a photo of my "Hog" in flight
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Old 10-19-2005, 09:32 PM
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Default RE: Sig Astro Hog "Engine recomendations

[8D]Outstanding photo and a great looking Hog.
I noted your angular windshield. Looks like it
would be easier to install than the rounded
style per kit plans.
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Old 10-19-2005, 10:15 PM
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lalaland
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Default RE: Sig Astro Hog "Engine recomendations

Ugo Ferrari.....

That is One "Nice Looking" Astro Hog! I am building mine as a tail dragger too. Any suggestions on the amount of dehedral I should have in mine? I will cut it down from what the plans state I think. How much, I'm not sure yet.

I'm still not sure what engine to use even though I thought I had my mind made up in my last thread. I just finished a Goldberg Anniversary Piper Cub (Clipped Wing) that weighs about the same as the Astro Hog, 7-7 1/2 lbs. and stuck an O.S. 46AX 2-Stroke on it and its not that great on take-offs off the grass and not the fastest cub on earth, yet flies nicely once airborne (just like a cub) My last Cub had a .61 super tigre on it and about tore the wing off full bore!. Made my ailerons flutter too. Had to cut back the throttle once airborne with the .61 Super Tigre on it but No problems getting that one off the ground, grass or no grass...lol

I wonder if my O.S. FL 70 4-stroke that I have now has the same power as the O.S. 70 II Surpass 4-stroke for my Astro Hog? I still might go with the O.S. 61 FX or a Super Tiger .61 when all is said and done. I want a little "more" than just enough power to get it off the ground once it's airborne.

Now I'm hearing about tip-overs on take-offs with the Astro Hog tail dragger. Wonder if I should just install an aluminum main gear under the fusalage or have the main in the wing since I have a grass runway? I land planes pretty nicely so I wouldn't worry about tearing it off on landing it. Take-offs? Well I'm not sure whether my hog would tip over or not! Never tried one yet.

I tell ya, If it ain't one thing it's another, but it sure is fun having them in your possession and having others help ya out when ya need some good advice in here.

Thanks for all for all the help.
-------------------------------------

wilinfla..... Your "Hog" looks very nice too with that color scheme! Good job on it!

Can't wait to get mine built!

Big Dan "Da RC Dummy"
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Old 10-20-2005, 06:29 PM
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Default RE: Sig Astro Hog "Engine recomendations

Jerry/Dan, Thanks for the compliments. The windshield I put on was one that I had from an old PT-19 kit, I can't remember which one though. Dan, I don't think you will have any problems with the nose overs as long as you get the gear good and tight so that it can't shift backwards on you. Once I had mine secured properly it handles great on the grass field where I fly. Robart strut covers give it a nice World War 2 look.
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Old 10-20-2005, 07:49 PM
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lalaland
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Default RE: Sig Astro Hog "Engine recomendations

wilinfla

Did you take any dihedral out of your wing when you built it? I plan on making mine at least 50% less than what it calls for.

My special main and tail gear arrived today from Sig. I will install it as plans call for under the wing for the tail dragger version. I want it to look like the original Hog. I'll make sure that gear doesn't pop backwards!

Thanks for the help.

Big Dan
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Old 10-20-2005, 08:54 PM
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Default RE: Sig Astro Hog "Engine recomendations

Well, as long as we are showing our pigs.....here's mine

Built stock except dual aileron servo and the taildragger option. Saito .72 and love it.

Mike

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Old 10-20-2005, 09:01 PM
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Default RE: Sig Astro Hog "Engine recomendations

[8D]For those of you who have built the Hog per kit plans/specs,
have you been satisfied with the performance of the ailerons
using the single servo control for both ailerons??
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Old 10-21-2005, 07:12 AM
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Default RE: Sig Astro Hog "Engine recomendations

Huggins,

Thanks for the pic of your "Pig" - That really looks great!

I'm still debating what engine to use in mine. Since they look more like an airplane I think it should have more of a real airplane sound to it as the 4-strokers do.

Maybe the 4-stroke is the way to go, but not to overpowered and have the tail feathers come off like my old goldgerb piper cub almost did at full throttle with a S.T. .61 on it! Ailerons fluttered bad, but on take-offs, that thing was up off the runway in no time at all!

I've never used a 4-stroke yet and I am wondering if I would incounter many problems with it like others say they do. Nothing worse than getting to the flying field with an engine that won't run properly or having it go to the doctor and the doctor ain't in. I'm like a doctor without a license when it comes to repairing engines. Maybe if I knew the basics on upkeep on a 4-stroke I'd feel a lot better.

More "Hog" pics welcomed here....

Thanks,

Big Dan
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Old 10-21-2005, 09:36 AM
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Default RE: Sig Astro Hog "Engine recomendations

Thanks for the kind words fellows ! (Jerry & Will ) It was a labor of Love ! Will, Your Hog is gorgeous !
I made no changes to the dihedral. I built it as per plans. Why mess with perfection ? Remember, this plane flys on the wing...Not meant for 3D Crap !! Like Hovering a Cub! GAG ! It can take off with !/2 throttle (With a little headwind). It is a beautiful site to behold when she gets up on the mains and slowly lifts off ! I'm getting chills ! LOL ! I don't understand why folks want "Just a little more power" ! This plane is a nice relaxing flyer....not meant to burn up the runway ! Maybe I'm getting old (74 yrs.). Anyway, If you have the need for "just a little more" Go for it !
If I remember, The landing gear provided in the kit will be to short to be wing mounted as per tail dragger, but another longer gear can be purchased from the Mfgr. I just bent a set from 3/16 wire. 5/32 is to light. To prevent noseing over, I bent the gear towards the Leading Edge and hold UP elevator whilst taxiing. Worked out for me.
As you will see, It's not an easy build....Just keep the teeth sharp on your CHAINSAW !! LOL !

Did I forget anything ?

Ugo
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Old 10-21-2005, 09:46 AM
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Default RE: Sig Astro Hog "Engine recomendations

Definitely use TWO servos for the ailerons !! How did I forget to mention THAT !!! !![X(]

Ugo

HUGGINS... Now that is NICE !
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Old 10-21-2005, 09:56 AM
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Default RE: Sig Astro Hog "Engine recomendations

I didn't build my Hog. I bought the kit to be my first build. When I got the book open I realized it was more than I could handle. I had it built by a man in Louisiana and he built it per plan. Before I damaged the gear block, and installed fuselage mountd gear, my plane would sometimes nose over on grass.

One thing I've seen suggested for the tail dragger version is to move the gear blocks forward in the ribs by about a half inch. Since the notches are not precut at all, that would be relatively easy to do.

I really like my plane. I think the 70 four stroke is plenty for a Hog. My brother has one with OS 91 four stroke. His plane has stronger vertical pull but that seems to be the only difference in how they fly.
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Old 10-21-2005, 10:08 AM
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Default RE: Sig Astro Hog "Engine recomendations

Carrell, Your .70 FS will be fine for your Hog ! Don't go butchering up the wing![:-] If the Fuse mounted gear is secure, Use it, and enjoy flying your plane ! Make all the mods mentioned on your NEXT Hog !

Let us know how it goes !!
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Old 10-21-2005, 12:37 PM
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Default RE: Sig Astro Hog "Engine recomendations

[8D]Did you use standard size servos for the ailerons?
If so, was the fit tight or is there wiggle room?. Or, did
you use the slimmer aileron servos?

Thanks.
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