Author Topic: Double Eagle Fuselage - Brazed  (Read 4896 times)

Offline Texas Flyer

Double Eagle Fuselage - Brazed
« on: October 06, 2015, 11:32:50 AM »
Re: Brazed Fuselage

I met with the son of the deceased builder of a Double Eagle fuselage.

The father had finished a Space Walker II, and started the Double Eagle.

The ribs, rudder pedals, and the fuselage were completed.
The landing gear is not complete.
The spoked wheels are available.
The son hasn't located the Plans yet.

Two technical questions:
1. He brazed the fuselage. Can it be unbrazed, metal cleaned, then welded?
2. He used two part epoxy for gluing the ribs. Do you think that is acceptable?

Would this project be worth buying?
How much would you pay?
Thanks.


---------------------------------------
Posted the same question on HBA and the consensus was not to braze 4130 for aviation use.  Also, the tubing couldn't be properly cleaned and welded.  Could cut it up and use the shorter pieces elsewhere.  Ribs would be ok if proper epoxy was used. One suggested he'd buy it for no more than $300.  If you are interested in purchasing, let me know.

Offline Tom XL-7

Re: Double Eagle Fuselage - Brazed
« Reply #1 on: October 07, 2015, 02:06:19 PM »
2nd question first. The specified adhesive for the ribs would be t-88 which is a two part epoxy.  The open question is what was used. Hardware store epoxy could have all kinds of specs. Probably not the end of the world as in probably way more strong than required. Probably is not a good answer at 3500 feet.

1st question, yes you could take it apart but no you could not clean it. The welds would be contaminated.
I am not going to go here but I will mention that a well done fillet brazed fuselage with the proper rod can be extremely strong and durable. Remember that was just a mention. It would require more skill and would be slightly heavier than a welded fuselage.

Buying a project can save a lot of money and time but you have to know what your buying. If the build is not well documented I would personnally walk away
But that is up to the buyer. You have to have full confidence in what you are buying and no one can decide that for you.
Tom XL-7

Offline Tom XL-7

Re: Double Eagle Fuselage - Brazed
« Reply #2 on: October 07, 2015, 02:34:52 PM »
So now I feel the need to clarify my comments.

Most important- there is one method approved for fabricating a homebuilt fuselage. That is welding. You have two choices of heat, Gas or TIG.
There are production aircraft which are mig welded. I am specifically calling out home built . so gas or tig.
I used two qualifing words one was "probably" the other was "could". Could is much worse than probably. 
 If you leave the approved methods it is very important that you fully understand the technology and methods that you are substituting and their effect on the finished assembly.
 Oh just to mention; there are fabricators who glue tubing together!
That's all
Tom XL-7

Offline Texas Flyer

Re: Double Eagle Fuselage - Brazed
« Reply #3 on: October 07, 2015, 02:41:51 PM »
From what others have told me since my first post, your recommendations are exactly what other experienced builders have suggested. 
I appreciate you sharing your wisdom.
As the song says...you got to know when to hold them...know when to walk away.  
Thanks a bunch!

Offline Texas Flyer

Re: Double Eagle Fuselage - Brazed
« Reply #4 on: October 07, 2015, 02:50:10 PM »
Tom.
Does XL-7 mean you have built a Legal Eagle XL?
Did you modify the plans?  What engine?
Is it flying, etc.?
If you built another one, what would you do differently?
Thanks

Offline Texas Flyer

Re: Double Eagle Fuselage - Brazed
« Reply #5 on: October 07, 2015, 07:31:43 PM »
I just received an email from the owner.
He doesn't know what the fuselage and misc parts are worth, but suggested $1,000 as the selling price.
I told him that if it had been welded vs brazed, then that would probably have been a great price.

He also said the wood glue used on the ribs was QuickCure.5. Two separate bottles.  (1) Epoxy. (1) Hardener

So, I'll continue searching and dreaming.
Thanks

Offline Tom XL-7

Re: Double Eagle Fuselage - Brazed
« Reply #6 on: November 22, 2015, 07:08:59 AM »
Sorry I missed your older post about XL-7
XL-7 is not built. 7 is probably the first plan set sold to the general public. Earlier sets are distributed to people for review purposes.
The sad part is I am sitting on enough steel , alum, and wood to build the fuselage, tail and wings.
Furthermore It was not easy for me to free up the $1634.90 for the above from other household/family needs.
The date on my invoices is july 2011. Which would be the last time I was at Oshkosh. Picked up there to avoid shipping costs. I always went to Oshkosh anyway.
But I have let stuff get in the way and have not been back or found time for XL-7.
The weather has been unusually mild but the cold midwest winter will soon be upon me and it is as always my intention to finish my build space (attic)and get on with it. 
Maybe some positive news around the holidays.
The saying goes "make time don't find time"
But after my nap it's time to go to bed.
 Tom XL-7
I can sleep when I'm dead

Offline Texas Flyer

XL-7
« Reply #7 on: November 22, 2015, 12:25:59 PM »
Move to Texas & together we'll get er done. 
Stay warm. 
Thanks

Offline scottiniowa

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Re: Double Eagle Fuselage - Brazed
« Reply #8 on: November 22, 2015, 02:14:33 PM »
So now I feel the need to clarify my comments.

 
 Oh just to mention; there are fabricators who glue tubing together!
That's all
Tom XL-7

Please do tell Tom, one fabricator that has used glue to hold 4130 together...???  New one on me!
best email address:  irondesignairparts@gmail.com

Offline Tom XL-7

Re: Double Eagle Fuselage - Brazed
« Reply #9 on: November 22, 2015, 03:49:23 PM »
I did not look up the post you are referring to but:
I remember it because it is true Scott.
First of all I don't think I referenced 4130 steel
Second they are glueing everything including skins. I have a high school classmate and friend : a metalurgist with one of the few steel producers in trhis country who wants to know what I can do with 0.005 steel sheet. Any ideas?
My mental reference belonged to bicycle frames which I have a lot of experience with..
As heavy as I am I still ride bicycles, for exercise now , for transportation  during those ancient education years.
I have always liked 4130 brazed frames
the world has gone to alum.
Someone with bolt cutter usurped my steel bike and a lot of other things. 
I replaced with an alum frame with carbon fiber forks.
The bike feels like I am riding  without a seat over railroad tracks.
The 4130 frames are accused of flexing during the power stroke.
Yes but wouldn't it unwind when the power stroke is off ?
Regardless I have for 40 years used traps so I can pull on the upstroke as well as push on the down.
The glued frames are alum bicycle and three wheel designs. I will dig up a reference at my leisure but this crap has been going on for years .
Note I didn"t say I approved
Tom XL-7
  Wow I googled gluing alum frames, Imagine that! I won't bother you with the details

Offline scottiniowa

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Re: Double Eagle Fuselage - Brazed
« Reply #10 on: November 23, 2015, 10:13:05 AM »
I did not look up the post you are referring to but:
I remember it because it is true Scott.
First of all I don't think I referenced 4130 steel
Second they are glueing everything including skins. I have a high school classmate and friend : a metalurgist with one of the few steel producers in trhis country who wants to know what I can do with 0.005 steel sheet. Any ideas?
My mental reference belonged to bicycle frames which I have a lot of experience with..
As heavy as I am I still ride bicycles, for exercise now , for transportation  during those ancient education years.
I have always liked 4130 brazed frames
the world has gone to alum.
Someone with bolt cutter usurped my steel bike and a lot of other things.
I replaced with an alum frame with carbon fiber forks.
The bike feels like I am riding  without a seat over railroad tracks.
The 4130 frames are accused of flexing during the power stroke.
Yes but wouldn't it unwind when the power stroke is off ?
Regardless I have for 40 years used traps so I can pull on the upstroke as well as push on the down.
The glued frames are alum bicycle and three wheel designs. I will dig up a reference at my leisure but this crap has been going on for years .
Note I didn"t say I approved
Tom XL-7
  Wow I googled gluing alum frames, Imagine that! I won't bother you with the details
Hi Tom,
 Because this was on the Legal Eagle forum site, was the reason I thought maybe you were referring to 4130N tubing being glued together as all the frame of the various models are of such material.
And because it was a ultralight forum, I thought you were referring to aircraft and not bikes. So my mistake there.

I did google the "gluing of alum frames" as you said. Certainly interesting, Every example that I found showed or discussed some kind of plug or in terms of building a cluster center or core. Probably good for production type of building, Though making cores or plugs might be a bit of a trick to then follow up the gluing of tubes. (in the case of our birds)

Now that I am knowing what you meant, like I said, interesting in the area that it is used.
cheers
best email address:  irondesignairparts@gmail.com

Offline Tom XL-7

Re: Double Eagle Fuselage - Brazed
« Reply #11 on: November 23, 2015, 03:53:24 PM »
Yes  this subject here is 4130 and I should have mentioned the adhesive use for alum.
The use of a lug just like in a brazed frame(bicycle) is most likely used .
I did not mean we could  or should use the tech , I added it in as an interesting thing and actually felt rather dismissive of it.
There is a welding book that is quite popular by a William French. In it he recounts receiving a cardboard tube of 4130 and he quiickly made a racecar chassis that weekend .  Brazed! Again brazing tubes into lugs is one thing but getting things to fit up tube to tube is another. For those who don,t get a clear reference to a lug ;
copper plumbing is a fair visual comparrison.  The tubing fits into th elbow ,tee, whatever very snugly and the solder fills the gap. That is the way I see brazing. Not just for tubing but very well fiiting pieces with the braze as a filller.  There are some modern brazing rods that claim weld like performance. Perhaps I will get my hands on some and do some testing on non-critical stuff.
 On a very similar note aircraft skins are being glued on, skipping the rivets. But then again we use fabric.
with that I'll let the glue thing die, I don't need to step in it again.
Tom XL-7

Offline Dan_

Re: Double Eagle Fuselage - Brazed
« Reply #12 on: November 23, 2015, 04:37:28 PM »
There is a welding book that is quite popular by a William French.
Tom XL-7


I bought Richard Finch's book.  My opinion is very low of this book --save your money it is mostly hype for selling tig equipment.  

Spend your money on a real aircraft welding book...
 http://www.amazon.com/Aircraft-Welding-L-S-Elzea/dp/1559182911/ref=sr_1_2?ie=UTF8&qid=1448321437&sr=8-2&keywords=aircraft+welding

It is an aircraft welding course.  Do the exercises in this book and you will without question be able to pass the FAA weldor certification test they used to have.