first off I'm a beginner. Tis is only my second kit. my first was a four star 60.I'm in the process of building a sig astro hog.Im building the tail dragger version.The kit said it can be flown with a 40-60 size two stroke engine.I already own a supertiger GS40. Is this engine sufficient for this plane or will it be underpowered. Im just a Sunday flyer. The kit also said to use a non knurled engine why?

The kit was designed in the 1950s. The available engines at the time were something like .35s from what I've been told. The kit box says the plane should weigh 7 to 7.5 pounds. That's pretty heavy for a 40 engine by today's standards. It seems most 40 size planes weigh 6 pounds or less.

So, compared to how it flew in the late 1950s, it will be overpowered. Compared to a modern sport plane it will be underpowered.

I do not know what a 'knurled' engine is.

My brother has a Hog with an OS 91 four stroke. It is definitely not underpowered but it does not have unlimited vertical climb capability.

I have a Hog with an OS 70 four stroke. Mine has not been flown yet, so I cannot comment on its performance.

I have an astro hog with an os 91 four stroke in it and it flys with great authority. Probably would fly with less, but I would question whether a 40 would be adaquate,especialy if this is a plain bearing engine. They don't as a rule have as much power as a bb engine. I would think a ball bearing 46 or larger[52 to 70 four stroke or 60 two st] would have much more authority.

I have a Magnum 80 4 stroke on my Hog and it flies great with that. I built mine as a tail dragger as well and even with the 4 stroke up front I still had to add some nose weight to get it balanced correctly. You will love the way it flies when you get it finished.

Astro Hogs are at the top of the list of great flying planes. INMO they would fly best with either a 70 4stroke or a 60 2-stroke but I wouldn't put anything smaller than a .50 sized engine. I recomend that even though it does not look as good to build it with a trike gear or atleast install the hardwood blocks in both locations on the wing so you can change it later. My brothers and other taildragger Hogs I've seen and flown can nose overbadly on take-offs and landings. Sig should come out with a new version of this kit thats laser cut they could sell a ton of Hog-ARF's if they would make them too.

I am building a Hog Bipe kit with a TT .91 (26 ozs.) on it. I have a Saito .91 (21 ozs) so depending on how it balances I will decide which engine to use. I'm anxious to see how it flies when finished.

My hog with as a tail dragger flys great and you have to work at it to nose it over. I put the landing gear on the fusalage in front of the wing saddle. used an aluminum gear. This puts the gear a little more ahead of the wing so it is more stable on the ground.I mounted the gear backwards so the axles were about 1" ahead of the wing. This makes it handles good on the ground with no tendancy to nose over.

Hi plunk,

You made a great choice for a second plane. In my Hog I have a 15 year old Saito 65 w/ a 12/6 MAS scimitar prop. It pulls it with good results. Not a lot of vertical, but enough for me.

As for the nosing over problem in the taildragger configuration, if you use the wire landing gear that came with the kit, you need to bend them forward about 15 degrees. Do not leave them the way they come out of the box! The HOG will nose over upon landing. Don't ask!

And for the 40 LA powering it, I do not believe that the engine is enough to haul it around. It is better to have too much power than not enough. You can always use the throttle stick. It was always taught to me as:
"Tis better to have and need not, than to need and ain't got!"

Have fun with the HOG

Mic

I think you should use a Veco 61 to be historically accurate! Oh, and no muffler just the exhaust baffle.

I've got a Magnum .46 XLS in mine. Plenty of power.

That's my Hog in my Avitar picture ! It weighs 9 lbs. and is powered by a Thunder Tiger .60 !
Plenty of power, but I would not go with less.. It will perform most of the basic maneuvers. Good tips on getting the LG bent foward ! Mine's a Tail Dragger too and tends to nose over unless you apply back stick during taxiing.
Ugo

I just finished one not to long ago...I put a saito 91gk in it. It is a tail dragger as well, fuse has been glassed and the wing was clothed.
Good luck.
charles