The Aerodrome Home Page
Aces of WWI
Aircraft of WWI
Books and Film
The Aerodrome Forum
Sign the Guestbook
Help
Links to Other Sites
Medals and Decorations
The Aerodrome News
Search The Aerodrome
Today in History


Learn how to remove ads

The Aerodrome Forum

Learn how to remove ads

Go Back   The Aerodrome Forum > WWI Aviation > Aircraft > Replica Aircraft


Replica Aircraft Topics related to the construction of WWI replica aircraft

Like Tree331Likes

Reply
 
Thread Tools Display Modes
Old 30 May 2008, 02:03 PM   #71 (permalink)
Forum Ace
 
Nick's Avatar
 
Join Date: Mar 2006
Location: Melbourne, Australia
Posts: 838
 
Quote:
Originally Posted by brisfitworks View Post
Nick:

On our Camel we used laser cut 4130N sheet. Obiously, we have no data from it on fatigue life and cracks appearing but the discussion about bending inducing cracking or micro cracks is revelent.

When I first started bending up brackets, especially the fwd attachment clips on the stab (Sopwith dwg. A-2481) I got cracking in the corners of the bend at the cut edge. There was no signs of over stressing on the outside face of the bend even when viewed with a 10x glass.

Because of edge hardening by the laser, we had a lot of issues with drilling out or reaming holes (I drew them a bit undersized to drill or ream out for a better finish against the bolts and clevis pins). So I suspected edge hardening from the laser was a cause of cracking at edges of bends.

I had talked to the heat treatment/hardening shop we use at work about bulk annealing parts before forming but they were concerned about warpage from uneven heating. If I had stacks of 20-50 of each, they said, they could be tightly wired together to make them more like a block of metal to avoid warpage. Since I was only building one Camel I went for old fashion torch annealing.

For remaing brackets I used a oxy-acetylene torch to anneal the edges and got much better results - none or minimal cracking which was then repaired.

When I got cracking at the bend I went over the edge at the bend with a TIG torch to melt back and seal the surface.

If I had to do again and what I am investigating with the F2b is waterjet cutting accuracy and costs versus some sort of sandwhiching plate for annealing and normalizing laser cut parts.

Sorry, a bit late for where you are today, but I will tell you this from my experience with our museum aircraft - I am always amazed at what my training tells me will fail yet lasts just fine for decades of use. I have seen misuse of materials and all sorts of workmanship failures and most failures are due to other causes.

Point is, I am not convinced you need be as worried and have to strip all the your carefully finished parts.

Oh to be in mass production of all these bits and planes and so easily afford destructively testing everything ;-)
Many thanks for your input Bill.
I think I also with any further fittings I get cut will go the water jet way. I made the same mistake pre cutting with smaller holes and then drilling them to size. Once hardened by laser cutting it's a heck of a job drilling them out. Also the amount of work required grinding down all the edges before bending is very time consuming.

Cheers, Nick
Nick is offline   Reply With Quote
Old 31 May 2008, 03:50 AM   #72 (permalink)
Scout Pilot
 
brinesharks's Avatar
 
Join Date: Mar 2005
Location: Melbourne
Posts: 426
 
Quote:
Originally Posted by Nick View Post
How would I go about testing them.
The simplest way would be to rig a sacrificial one up as it would be in the aircraft (ie. use scrap pieces of spruce and rigging wire but short lengths) then subject it to your maximum expected load (in extension?). I would suggest it would need some thought as to how to actually exert that much pull! You will probably see your wire or timber fail first. Then magnaflux the bracket to see if there were cracks forming. If the bracket fails before you reach maximum load then you would need to investigate why it did and what the implications were. This would still not be a convincing test in engineering terms but it's always a balance of cost vs benefit.

Now this would all make an engineer water at the mouth, but for us it's a bit of an endeavour. What I recommend is to continue the build but talk to RMIT Aerospace department and see if there is a masters or PhD student who needs a project! I'll ask my old lecturer if he can reommend some one. At the very least one might be able to design a test regime. I will also ask some of the test engineers at work about some of the techniques that could be used to give you the confidence you need without wasting your time and money. Sorry to open a can of worms!

I don't think this is a 'war stopper' - more about giving you engineering confidence in your build.
__________________
We have no effective screening methods to make sure pilots are sane.

Dr. Herbert Haynes, Federal Aviation Authority.
brinesharks is offline   Reply With Quote
Old 31 May 2008, 04:22 AM   #73 (permalink)
Two-seater Pilot
 
Join Date: Sep 2005
Location: Adelaide South Australia
Posts: 174
 
Sopwith Snipe Project

Hi Nick

I have followed your project with interest and a great deal of admiration. Back in the eighties I made a tentative start on a Camel but business and personal pressures got in the way.

I have a request to make. You mention Phil de Gruchy as having made your wheels and that he also makes or repairs old race car wheels. I am currently restoring a 1926 French sports car and am looking for some expert who could respoke a set of wheels for this car. If it does not breach confidentiality would it be possible to obtain his address?

You mention the RAAF Museum at Point Cook. I know it well as I was the Senior Engineer Officer on the Base for most of the seventies and had quite a lot to do with the early collection of aircraft.

Best regards

Mustang

Last edited by mustang; 31 May 2008 at 04:25 AM. Reason: word repeated insentence
mustang is offline   Reply With Quote
Old 31 May 2008, 07:39 AM   #74 (permalink)
Forum Ace
 
Joe Perkel's Avatar
 
Join Date: Oct 2007
Location: Miami / Sebring, Florida
Posts: 1,308
 
1918 Reference

Nick,

Take a look at page 59 & 60 Aeroplane Construction and Assembly - Google Book Search

These two period references are linked on my reference page. Came across this today looking at fittings / rigging info.
__________________
Joe

http://sopwith-baby.com/

M.V.R. Showed us what happens when you don't stick to your own rules.
Joe Perkel is offline   Reply With Quote
Old 31 May 2008, 01:36 PM   #75 (permalink)
Forum Ace
 
Nick's Avatar
 
Join Date: Mar 2006
Location: Melbourne, Australia
Posts: 838
 
Quote:
Originally Posted by brinesharks View Post
The simplest way would be to rig a sacrificial one up as it would be in the aircraft (ie. use scrap pieces of spruce and rigging wire but short lengths) then subject it to your maximum expected load (in extension?). I would suggest it would need some thought as to how to actually exert that much pull! You will probably see your wire or timber fail first. Then magnaflux the bracket to see if there were cracks forming. If the bracket fails before you reach maximum load then you would need to investigate why it did and what the implications were. This would still not be a convincing test in engineering terms but it's always a balance of cost vs benefit.

Now this would all make an engineer water at the mouth, but for us it's a bit of an endeavour. What I recommend is to continue the build but talk to RMIT Aerospace department and see if there is a masters or PhD student who needs a project! I'll ask my old lecturer if he can reommend some one. At the very least one might be able to design a test regime. I will also ask some of the test engineers at work about some of the techniques that could be used to give you the confidence you need without wasting your time and money. Sorry to open a can of worms!

I don't think this is a 'war stopper' - more about giving you engineering confidence in your build.
Thanks Bryan,
I have a couple of spare fittings that I could finish off and then test to destruction. I have contacted a design engineer that I met at about the time I started this so hopefully he may be able to point me in the right direction.

Cheers, Nick
Nick is offline   Reply With Quote
Old 31 May 2008, 01:43 PM   #76 (permalink)
Forum Ace
 
Nick's Avatar
 
Join Date: Mar 2006
Location: Melbourne, Australia
Posts: 838
 
Quote:
Originally Posted by mustang View Post
Hi Nick

I have followed your project with interest and a great deal of admiration. Back in the eighties I made a tentative start on a Camel but business and personal pressures got in the way.

I have a request to make. You mention Phil de Gruchy as having made your wheels and that he also makes or repairs old race car wheels. I am currently restoring a 1926 French sports car and am looking for some expert who could respoke a set of wheels for this car. If it does not breach confidentiality would it be possible to obtain his address?

You mention the RAAF Museum at Point Cook. I know it well as I was the Senior Engineer Officer on the Base for most of the seventies and had quite a lot to do with the early collection of aircraft.

Best regards

Mustang
Hi Mustang,
Phil de Gruchy trades under the name of "Lightfoot Engineering" in Mont Albert, Vic. I'll PM you his phone number. He'd definately be the guy to do your wheels. A 1926 French Sports car...now that sounds interesting, great stuff.
Point Cook is a great museum and developing all the time. A very helpful bunch of people there.

Cheers, Nick
Nick is offline   Reply With Quote
Old 31 May 2008, 01:51 PM   #77 (permalink)
Forum Ace
 
Nick's Avatar
 
Join Date: Mar 2006
Location: Melbourne, Australia
Posts: 838
 
Quote:
Originally Posted by Joe Perkel View Post
Nick,

Take a look at page 59 & 60 Aeroplane Construction and Assembly - Google Book Search

These two period references are linked on my reference page. Came across this today looking at fittings / rigging info.
Hi Joe,
Many thanks for that, I have tracked down a copy and ordered it.

Cheers, Nick
Nick is offline   Reply With Quote
Old 31 May 2008, 02:43 PM   #78 (permalink)
Forum Ace
 
Joe Perkel's Avatar
 
Join Date: Oct 2007
Location: Miami / Sebring, Florida
Posts: 1,308
 
Quote:
Originally Posted by Nick View Post
Hi Joe,
Many thanks for that, I have tracked down a copy and ordered it.

Cheers, Nick
Nick,

You're most welcome! Check out page 65 Aeroplane Construction and Assembly - Google Book Search which is relevant to the recent radius discussion.

Note the cavalier attitude of the author with respect to field replacement by the mechanic. Perhaps we have a bit of a "space age" mentality by comparison, which can't be a bad thing.
__________________
Joe

http://sopwith-baby.com/

M.V.R. Showed us what happens when you don't stick to your own rules.
Joe Perkel is offline   Reply With Quote
Old 31 May 2008, 02:47 PM   #79 (permalink)
Two-seater Pilot
 
brisfitworks's Avatar
 
Join Date: Sep 2004
Location: Orangeville, Ont., CANADA
Posts: 119
 
laser cutting vs waterjet

Nick:

To drill laser cut 4130 we used solid carbide drills and reamers. Bit expensive but it did the job.

What have you been told about the accuracy of waterjet cutting?

I keep getting conflicting answers. Laser is definitely accurate enough but the heat is an issue. Some waterjet guys quote me large tolerances like +/-.020" and others say they are as accurate as laser.

Real resulting tolerance is my only concern for waterjet will cut any material needed with wonderful results. If you draw it, you can all your aluminum panels, your plywood parts and even your fabric. I worked on some experimental units in the early 80's and it is very neat way to cut.

Quote:
Originally Posted by Nick View Post
Many thanks for your input Bill.
I think I also with any further fittings I get cut will go the water jet way. I made the same mistake pre cutting with smaller holes and then drilling them to size. Once hardened by laser cutting it's a heck of a job drilling them out. Also the amount of work required grinding down all the edges before bending is very time consuming.

Bill

Cheers, Nick
__________________
-------------------------------------------
Wm. K. Batter
www.greatwarflyingmuseum.com
brisfitworks is offline   Reply With Quote
Old 31 May 2008, 08:08 PM   #80 (permalink)
Forum Ace
 
Nick's Avatar
 
Join Date: Mar 2006
Location: Melbourne, Australia
Posts: 838
 
Quote:
Check out page 65 Aeroplane Construction and Assembly - Google Book Search which is relevant to the recent radius discussion.
Joe,
Not having much luck with getting any pages from Google Books so will turn straight to page 65 when it turns up in the post
Thanks, Nick
Nick is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -8. The time now is 02:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.0 PL2
Copyright 1997 - 2013 The Aerodrome