Sopwith Baby Project

Nick · 2 January 2009, 12:17 AM

Hi Joe,
Great drawings as usual.
Trying to get my head round the plan though why the bolt on Part G is not at 90 degrees to the face. Sorry to keep mentioning the Snipe but its all I’ve got to compare it to. Basically on that all Spar fitting bolts are at 90 degrees to the face as you’d expect. However where the main spar Joint box is actually attached to the centre section it is via a joint rod that goes right through both spars in one piece and so it is drilled though at 2 degrees, as that is the angle to the spars to go through both dead centre.
Are the Spars attached with bolts or a joint rod on the Baby?
As for the dihedral, as you’ve noted, it doesn’t show any. Possibly just a matter of a small 1 degree chamfer on each spar end and then resolved with the rigging.

Cheers, Nick

DamianL · 2 January 2009, 03:07 AM

Hi Joe

I'm fairly new to the forum (6 months) & have been following your thread with interest, I'm planning to build a replica Sopwith 1-1/2 Strutter.

I checked the Sopwith Pup drawings for the top spars and spar boxes. The drawings don't give details on the production method used to affect the dihedral.

The following drawing is of the top front spar, with just a note that the spar is set at 3 deg in the spar box.

The following drawing is of one of the spar box fittings, none of which mention 3 deg spar setting. The bolt holes (with exception of joint rod holes) are on a common centreline.

Note that drawing of spar box shows spar centreline at angle to spar box centreline.

Since the spar box construction makes no mention of a 3 deg offset or setting, but spar drawing mentions setting of 3 deg in spar box, would this mean that during assembly spar end was planed & sanded to affectively make a 3 deg tennon on the end of the spar?

Is this what you had assumed for the Baby, or were you lookign to incorporate in the spar box?

Note: This is my first attempt at attaching images, hope this works ok.

Regards

Damian Latimer

Joe Perkel · 2 January 2009, 03:16 AM

Quote:

Originally Posted by DamianL

Hi Joe
The following drawing is of one of the spar box fittings, none of which mention 3 deg spar setting. The bolt holes (with exception of joint rod holes) are on a common centreline.

Note that drawing of spar box shows spar centreline at angle to spar box centreline.

Since the spar box construction makes no mention of a 3 deg offset or setting, but spar drawing mentions setting of 3 deg in spar box, would this mean that during assembly spar end was planed & sanded to affectively make a 3 deg tennon on the end of the spar?

Is this what you had assumed for the Baby, or were you lookign to incorporate in the spar box?

Damian Latimer

Damian,

Morning rush to get to work!

The off center hole must be as Nick also notes above, for the joint rod. Now that makes more sense.

I would have felt better if my drawing had shown the dihedral like the Pup end box drawing does, but now I feel better about that too!

Thank you very much for the input!,..tell us about the Strutter!! Pictures yet??

Joe Perkel · 2 January 2009, 03:20 AM

Quote:

Originally Posted by Nick

Hi Joe,
Great drawings as usual.
Trying to get my head round the plan though why the bolt on Part G is not at 90 degrees to the face. Sorry to keep mentioning the Snipe but its all I’ve got to compare it to. Basically on that all Spar fitting bolts are at 90 degrees to the face as you’d expect. However where the main spar Joint box is actually attached to the centre section it is via a joint rod that goes right through both spars in one piece and so it is drilled though at 2 degrees, as that is the angle to the spars to go through both dead centre.
Are the Spars attached with bolts or a joint rod on the Baby?
As for the dihedral, as you’ve noted, it doesn’t show any. Possibly just a matter of a small 1 degree chamfer on each spar end and then resolved with the rigging.

Cheers, Nick

Nick,

Now I feel better! It would have been nice for them to denote the dihedral though. Yes, it's a common joint rod, now I understand for the same reason as you note.

It occurred to me to maybe chamfer both as you note, but the drawing does specify center section spar. I wonder if maybe it's a bit less traumatic to mess it up on the shorter spar for a redo?

Thanks Nick!

Joe Perkel · 3 January 2009, 07:42 AM

In looking up the general dimensions of the Clerget today, I stumbled across this outstanding reference.

Airplane Engine Encyclopedia: An ... - Google Book Search

Jeff Brooks · 8 January 2009, 02:50 AM

Joe,

From one first time builder to another ... You seem to have enough information to start something. GO FOR IT~

I don't wanna come across as heckling you ... I just wanna encourage you to start, as starting IS the hardest part!

You should try making a small part like an elevator or rudder. This is how I started on mine. You cut your fabrication teeth on a part that is a small part ... something easily replaced, and you get a feel if you like building or not. Before you invest in lots of wood, metal hardware & tools. If it comes out well, it will encourage you to continue.

The first part I made for my plane was the rudder with my youngest brother. I had never welded anything, or even knew where to begin with fabrication. My youngest brother used to work at a fabrication place, so I asked him to stop by and guild me through it. I coaxed him with a 12 pack, as he wanted nothing to do with something that would kill me. But in a short time I realized that there is more than one way to build something, and as long as you keep at it, you will learn SOOO much!

By the way, the rudder I made with my brother is too heavy and will not make it onto my plane, but I can't bring myself to cut it up and reuse the metal as it was time well spent with my little brother. I think I am going to cover it with fabric and hang it somewhere!

Good Luck, and go for it! We are behind you!

Joe Perkel · 8 January 2009, 03:25 AM

Quote:

Originally Posted by Jeff Brooks

Joe,

From one first time builder to another ... You seem to have enough information to start something. GO FOR IT~

I don't wanna come across as heckling you ... I just wanna encourage you to start, as starting IS the hardest part!

You should try making a small part like an elevator or rudder. This is how I started on mine. You cut your fabrication teeth on a part that is a small part ... something easily replaced, and you get a feel if you like building or not. Before you invest in lots of wood, metal hardware & tools. If it comes out well, it will encourage you to continue.

The first part I made for my plane was the rudder with my youngest brother. I had never welded anything, or even knew where to begin with fabrication. My youngest brother used to work at a fabrication place, so I asked him to stop by and guild me through it. I coaxed him with a 12 pack, as he wanted nothing to do with something that would kill me. But in a short time I realized that there is more than one way to build something, and as long as you keep at it, you will learn SOOO much!

By the way, the rudder I made with my brother is too heavy and will not make it onto my plane, but I can't bring myself to cut it up and reuse the metal as it was time well spent with my little brother. I think I am going to cover it with fabric and hang it somewhere!

Good Luck, and go for it! We are behind you!

Jeff,

Ha, ,,,you should see where I'm living at the moment!

We rented the tiny spam can next door to our building project (2,400 sq ft addition) this past Oct, and still are tripping over unpacked boxes, it's a nightmare.

I am off to work this am, but on my next group of day's off, I'll snap a picture from across the street.

When I do finally start, after doing some ribs, I will also do the vertical stab / rudder combo, likely to be done in clear doped linen for the Sopwith logo. This to be hung on the wall as a motivator.

Really, itching to get started, thanks for the encouragement!

Joe Perkel · 9 January 2009, 06:25 AM

Whenever I'm not working with CAD, and have net access away from home, I continue searching for potential sources.

Found this this am which surprised me. I'm going to guess these are likely log-less and rendered unserviceable, but maybe not completely useless??

Motoart Continental Radial Engine

Anyone know anything about these, or have seen them before?

Joe Perkel · 10 January 2009, 07:41 AM

Quote:

Originally Posted by Jeff Brooks

Joe,

... I just wanna encourage you to start, as starting IS the hardest part!

Good Luck, and go for it! We are behind you!

Jeff,

The reason I am delayed, as of this morning, (at least the roof is going on today!). 12 months of this now, if it remains the single most stressful event of my life, then I will have been a lucky man!

The component shop is on the second floor in the back. The hangar / barn, will be in central Florida.

Thank you very much for your encouragement!

RobW · 16 January 2009, 06:17 PM

Joe,
I found a reference book you may be interested in... the original title was: Aeroplane Structures by AJ Sutton and Capt. Laurence Pritchard, 1919. Reprints can be purchased online under the title WWI Aircraft Airframs, Structures, & Components.
It is essentially a wooden aircraft engineering book. Way over my feeble brains capacity... discusses methods of construction, testing, measuring loads, etc...

thought you might be interested.

Rob