04-21-2016, 03:13 AM
Greetings everyone,
I have been kicking around building an onager for about two years. Bought some books but the information on the onager is so painfully thin, I don't think I have ever seen even a source say they were x number of feet long in the base.
Now in digging around I found someone that roughly figured out the thickness of the band by measuring the weight of the projectile and distance it could through. It makes a few assumptions from there.
His statement is that a "full sized" Onager would roughly be 20 US feet. Now that would make the bottom two rails about
4 tons if they were made out of decent oak. Now I can get trees at little to no charge and rough em in with a chain saw.
but with a total weight of about 5 tons I am not going to be moving it with out special equipment. So I was thinking half size.
at one ton per rail I could move this with a truck, abet in several trips.
Relevant paper here
Now I am of the anti-arrest post crowd. I read on here a discussion from several people about different ideas about what would work better. Things like the design with a pad low and angled to allow a full swing.
And someone (Robert perhaps) put up a design with the tension arm in the very front.
But my first question is assuming that the design of the Onager dose not allow the arm to smack into a cross beam why bother arresting the arm at all? I know the texts tell us it will splinter stone work but I won't fire it on cement.
The local police are going to have a heart attack when they get a call about a 10' version for the first time. So outside of town in a open field will be the firing place. Unless it is going to break the swing arm I could care less if it hits the ground.
Now I don't have the ability to steam bend something this big. So in order to get it off the ground and provide more swing for the bottom of the arm I am going to put "feet" if you will under the four corners. And notch them into place. I am thinking that it will provide enough height and if that won't do it I will just dig under the arm a bit. The feet will be the same size as the rails of the Onager and 2 or three feet long for stability. Does this sound stable enough? Not that I am going to be anywhere in the area when I set it off for the first time but I don't want to destroy it on the first shot either.
Lastly the ever present elephant in the room.
Sinew and horse hair are out as cord. Human hair would cost as much as paying someone to make one out of sinew.
So has anyone found anything better or have ideas for something that would work better then triple strand pre-stretchered nylon? I have considered used bungee jumping rope even but the rebound may be a bit dangerous.
Obviously I haven't made any progress on that one.
I have constructed a small model when this idea first came up and it worked well enough but I used surgical tubing (think wrist rocket tube) for the model and not totally surprisingly it flipped around when fired but a half sized one should be heavy enough to mostly stay put when fired. So since correct rope is out I am looking for something else that will work.
Sorry for the length.
I have been kicking around building an onager for about two years. Bought some books but the information on the onager is so painfully thin, I don't think I have ever seen even a source say they were x number of feet long in the base.
Now in digging around I found someone that roughly figured out the thickness of the band by measuring the weight of the projectile and distance it could through. It makes a few assumptions from there.
His statement is that a "full sized" Onager would roughly be 20 US feet. Now that would make the bottom two rails about
4 tons if they were made out of decent oak. Now I can get trees at little to no charge and rough em in with a chain saw.
but with a total weight of about 5 tons I am not going to be moving it with out special equipment. So I was thinking half size.
at one ton per rail I could move this with a truck, abet in several trips.
Relevant paper here
Now I am of the anti-arrest post crowd. I read on here a discussion from several people about different ideas about what would work better. Things like the design with a pad low and angled to allow a full swing.
And someone (Robert perhaps) put up a design with the tension arm in the very front.
But my first question is assuming that the design of the Onager dose not allow the arm to smack into a cross beam why bother arresting the arm at all? I know the texts tell us it will splinter stone work but I won't fire it on cement.
The local police are going to have a heart attack when they get a call about a 10' version for the first time. So outside of town in a open field will be the firing place. Unless it is going to break the swing arm I could care less if it hits the ground.
Now I don't have the ability to steam bend something this big. So in order to get it off the ground and provide more swing for the bottom of the arm I am going to put "feet" if you will under the four corners. And notch them into place. I am thinking that it will provide enough height and if that won't do it I will just dig under the arm a bit. The feet will be the same size as the rails of the Onager and 2 or three feet long for stability. Does this sound stable enough? Not that I am going to be anywhere in the area when I set it off for the first time but I don't want to destroy it on the first shot either.
Lastly the ever present elephant in the room.
Sinew and horse hair are out as cord. Human hair would cost as much as paying someone to make one out of sinew.
So has anyone found anything better or have ideas for something that would work better then triple strand pre-stretchered nylon? I have considered used bungee jumping rope even but the rebound may be a bit dangerous.
Obviously I haven't made any progress on that one.
I have constructed a small model when this idea first came up and it worked well enough but I used surgical tubing (think wrist rocket tube) for the model and not totally surprisingly it flipped around when fired but a half sized one should be heavy enough to mostly stay put when fired. So since correct rope is out I am looking for something else that will work.
Sorry for the length.