Thread Tools
Jul 07, 2003, 05:58 AM
Registered User

engine suggestions for an Astro-Hog


Hi all,

I'm currently building a SIG Astro-Hog, and I'm ready to purchase an engine. Would anybody have any suggestions for an engine size and your favorite brand. I want to use a 2-stroke to keep costs down. Also, I'm building the taildragger version. This is my first low-wing and taildragger, so any help is greatly appreciated.

Thanks a bunch,
Dan
Sign up now
to remove ads between posts
Jul 08, 2003, 02:54 AM
Sloping off....
leccyflyer's Avatar
Dan

I don't have any direct experience of the full sized Astro Hog, hopefully someone who has will be along soon to give you the benefit of theirs.

I do have a little baby MiniAstroHog that is just the right size for an OS.15FP

http://rcgallery.net/showphoto.php?p...t=1&thecat=500

and if the big one is anything like the small one she'll be an ideal first low winger- very stable and easy to fly but very capable of normal sports style aerobatics- a lovely model.

Good luck

Brian
Jul 14, 2003, 02:51 AM
Registered User
Tony Oliver's Avatar

Astro Hog


The original Astro Hog by Fred Dunn was in 1958 and was powered by a K&B Torpedo 35R/C. Variants had Veco 35s as well.

Information from 'Aeromodeller' - July 1958

Anything from 35 to 61 two-strokes will work (pretty high powered with the 61). Fourstrokes from 45 to 70 would be an equivalent.

Tony
Jul 19, 2003, 11:24 PM
Voices through wires? Ha!
Chas's Avatar

Them were the days lad...


Dan
I have the SIG kit in my mountain and just a few weeks ago I bought the perfect motor on eBay! It's the OSMax30, an old engine, but as I discovered you can still buy them un-run. Mine was thirty bucks!
The OS30 was later known as the "poor man's four-stroke" because it turned a large diameter, low-pitch prop at reasonable revs. Its long stroke and small venturi made it a ringer for the type of engines the Hog would have originally used - they weren't screaming powerhouses by any stretch. Fuel economy is fantastic and noise is minimal, I've run mine on the bench without a silencer at all. The engine is featherweight, and throttles very well indeed. If anything Sig's kit is lighter than the original so it should be perfect.
Fit this with an 11x6 (the size often used on a .61!) and you'll be puttering away with Dunham's ghost looking over your shoulder!
PS I've also bought a mint Kraft four-channel from the seventies, also on e-Bay and also the magic $30 figure, and it works perfectly, even the nicads hold for three hours. If you're careful, eBay is a goldmine.
Good luck
Cheers
Chas
Last edited by Chas; Jul 19, 2003 at 11:50 PM.
Jul 19, 2003, 11:31 PM
Voices through wires? Ha!
Chas's Avatar

By the way this was before OS were top dog!


I guess they were concentrating too hard not to type "prug"!
C
Jul 19, 2003, 11:44 PM
Voices through wires? Ha!
Chas's Avatar

and finally here 'tis


The debut...
Jul 20, 2003, 04:04 AM
Registered User
Tony Oliver's Avatar

Astro Hog


Chas, you've done it again!

You're absolutely correct about the 'poor man's 4-stroke' I have an early OS30 and it's still in good running order. I originally used it in a 6ft Fokker E111 which was more than a little overpowered by this motor. Despite its preference for larger slower running props, it was also used in a 3ft delta to good effect, so it's a pretty versatile motor.

It was noticeable that as motors became higher revving, it narrowed the suitability for particular aeroplanes. Only when 4 strokes became readily available did the larger, slower models become popular - there was always something wrong about a Bleriot with a motor doing high revs on a small prop.

Tony
Jul 20, 2003, 11:09 AM
Voices through wires? Ha!
Chas's Avatar
Aw, shucks...

Nice model Tony! It must be the RCM&E plan? Nice big fan on the front. We sometimes forget that rubber models often used 22" dia props, of 22" pitch!

Look at the way that silencer just pops out under the cowl in the inverted installation - just the job! I guess the tank was down low (hint hint, as he looks slobberingly at the Magnattila kit)...
I'm starting too many projects - again.

Speaking of props, I'm going to try to knock up a "Bilgri" type for high-geared electric, I'll let you know how I get on.
Best
Chas
Jul 20, 2003, 12:23 PM
Registered User
Tony Oliver's Avatar
No, it w asn't a plan - I built it 'on the board '- drew it up in side view on the board then the top view and tailunits - allflying so it looked like a birdcage at the back. I chickened out of wingwarping and used the flying and landing wires to keep some dihedral in.

The OS30 turned a 12 x 4, I think at ridiculously low revs, but the model only weighed in at around three and a half pounds. Control response was a bit slow - you needed to decide a few seconds beforehand what you wanted it to do.

After talking about it, I feel another one coming on.

Quick, nurse, the screens!

Tony
Jan 07, 2011, 02:12 PM
Registered User
Hi I have a 52 size motor, brand new in its box with the pipe. R700 ?
Jan 07, 2011, 06:57 PM
Old Timer
av8djc's Avatar
Danny

Mine I converted to electric in my transition from glow. As an old glow guy I never owned the 30 they're talking about but the old OS80H rear induction was another long stroke high torque 2 stroke that would work really nice on the hog. I feel you will need the power of a .91 or 100 ish to do the plane justice but it will fly on less.
Dave
Jan 07, 2011, 07:44 PM
Registered User
earlwb's Avatar
The Astro Hogs were flown with .35 engines at first and the engines kept getting larger and larger as time went on. I would look for a nice old .60 engine of some sort for the Astro-Hog. You don't really need a super powerful engine to fly it with. But you are welcome to run any .60 size engine you'd like, just remember you do have a throttle, you do not have to fly around WOT. A four stroke engine would work well too.

many years ago I flew a Astro-Hog using a Fox blue head .60 RC engine with an exhaust baffle and no muffler. No one used mufflers back then. The RC radio systems were huge, I used a MRC 4 channel early proportional system that had a gigantic receiver and four huge servos. The servo electronics was inside the receiver brick. The on board battery pack was sucked down fast, you could do two good flights before the battery pack got low. Anyway the engine outlasted the airplane. The old Fox blue head .60 is now in a Goldberg Tiger 60 airplane. The plane is quite similar in design and size to the Astro-Hog.

Oh yeah, in this thread here about Astro-Hogs you can get good ideas about what engine to run on them too: https://www.rcgroups.com/forums/showthread.php?t=903697
Last edited by earlwb; Jan 07, 2011 at 07:52 PM.
Jan 07, 2011, 08:24 PM
Voices through wires? Ha!
Chas's Avatar
All great responses guys, but since Danny asked his question about seven and a half years ago I guess he must be flying in the ToC by now! And Edwin, methinks, was just wondering how many South African Rand he could get for his .52 engine "with pipe".
Jan 08, 2011, 03:09 AM
NM2K
Quote:
Originally Posted by Chas
Dan
I have the SIG kit in my mountain and just a few weeks ago I bought the perfect motor on eBay! It's the OSMax30, an old engine, but as I discovered you can still buy them un-run. Mine was thirty bucks!
The OS30 was later known as the "poor man's four-stroke" because it turned a large diameter, low-pitch prop at reasonable revs. Its long stroke and small venturi made it a ringer for the type of engines the Hog would have originally used - they weren't screaming powerhouses by any stretch. Fuel economy is fantastic and noise is minimal, I've run mine on the bench without a silencer at all. The engine is featherweight, and throttles very well indeed. If anything Sig's kit is lighter than the original so it should be perfect.
Fit this with an 11x6 (the size often used on a .61!) and you'll be puttering away with Dunham's ghost looking over your shoulder!
PS I've also bought a mint Kraft four-channel from the seventies, also on e-Bay and also the magic $30 figure, and it works perfectly, even the nicads hold for three hours. If you're careful, eBay is a goldmine.
Good luck
Cheers
Chas

My wife's first engine was the Cox Babe Bee .049 and then, in R/C, the OS Max .35S R/C. She (the engine) lasted through three different models without any serious sign of wear. Even with me burning fuel with all synthetic oil (I didn't know any better - it was 1969 or 70). The engine used to land smoking, no kidding. Let it cool down, restart it, and it ran better than ever. I didn't know about the "green piston" that actually grew in size when over heated.

I have flown Astro Hogs with ASP .61 ABC engines on them. Frankly, it wasn't really over powered by today's standards. I would prefer it be powered with either an old Fox Eagle .60 (baffle piston) or a baffle piston K&B .60 (6550). Lots of power, but nothing excessive. Too much power can present some fairly severe trim problems if the model is set up as originally designed. I would think that Sig corrected all of that in their later edition kits. Even a nice four-stroke .61 to .91 sized engine would fly it nicely.


Ed Cregger
Jan 08, 2011, 08:15 AM
Old Timer
av8djc's Avatar
Quote:
Originally Posted by Chas
All great responses guys, but since Danny asked his question about seven and a half years ago I guess he must be flying in the ToC by now! And Edwin, methinks, was just wondering how many South African Rand he could get for his .52 engine "with pipe".

Note to self....remember to look at thread date


Thread Tools