Frame tube angles in the plans

[ultra]

Hello all,

One issue I've run into starting construction of my frame is that I know the lengths and thickness of the tubing of the XL frame however when it comes to assembly I have no idea what the angles of the tubing are in the plans. 

I've made the first rectangular tubing section for the engine mount and the second one for the cockpit but now I'm stuck trying to figure out what angle the tubes connecting them together should be. 

Is there any advice to be had when it comes to getting the base of the frame set up? I'm assembling the frame piece by piece rather than welding the whole frame at once.

[Dan_]

Here is some discussion on it...

https://www.eaglersnest.com/forum/index.php?topic=237.msg1067;topicseen#msg1067

[bmxmann]

I am just about done building my frame, and haven't needed any of the angles other than the top tube (granted, maybe I am doing something wrong).  Building just by the dimension put in the plans, going off measurements on my table, while following the guide Scott had put together and it has worked well.  The plans tell you where Station 1 needs to be, so you build a jig to hold station 1 in that position.  You know where station 2 and 3 are, and should have those marked on your table, so you bend the tubing up from station 2 to station 1.  Then you put your tail post where it should be with a jig, and make your bend at station 3 so your long sides are up to where they should be on the tailpost.  Really no need to know what angle those are at.  Then building up from there.   The only angle I checked/confirmed was the very top tube angle, which I think is the only one referenced in the plans.  I created a very short start guide based on how I did it. https://goo.gl/photos/T99c8eo5hoY7PNUk7

Granted, re-reading your post seems like you are doing things a bit differently than I did...  so your results may vary.  but either way, if you can mount it to the table/jig so they are in the right spots, then you just cut/bend metal to connect them.

[Dave Stroud]

Ultra....are you saying you will make a rectangle of tubing for stations 1,2,3 and join them with shorter connecting pieces of tubing and that is what you need the angles for ?

[Vince Carucci]

I like to refer members to the videos in this link whenever they have questions about the fuselage. If you have a little time, watch every video. It's a great tutorial. 

Fuselage Build

Subscribe to his YouTube page. 

Vince

[ultra]

Ultra....are you saying you will make a rectangle of tubing for stations 1,2,3 and join them with shorter connecting pieces of tubing and that is what you need the angles for ?

Yes thats exactly what I'm doing, but I just figured out the sections behind section 3. I cut the tubing for the rear of the plane and will notch and tack it sometime this week, the only thing Im having trouble with now are the sections in front of section 3. I have the section 1 and 2 rectangles already made and welded.

[scottiniowa]

Ultra....are you saying you will make a rectangle of tubing for stations 1,2,3 and join them with shorter connecting pieces of tubing and that is what you need the angles for ?

Yes thats exactly what I'm doing, but I just figured out the sections behind section 3. I cut the tubing for the rear of the plane and will notch and tack it sometime this week, the only thing Im having trouble with now are the sections in front of section 3. I have the section 1 and 2 rectangles already made and welded.

 I am with Dave here,  Mr. Ultra, other than the front station (motor mount or nose) how are you intending, to include these squares to your lower longerons?

[scottiniowa]

Hello all,
 

Is there any advice to be had when it comes to getting the base of the frame set up? I'm assembling the frame piece by piece rather than welding the whole frame at once.

I don't know if this is advice or not, but----   Have you ever seen a frame built the way it sounds like you intend to build?   if so, I would sure like to see how they did it.

So what I am getting at, while I am all for new ideas, this simply sounds like a path NOT TAKEN by anyone before. I would really think that over...

[ultra]

Ultra....are you saying you will make a rectangle of tubing for stations 1,2,3 and join them with shorter connecting pieces of tubing and that is what you need the angles for ?

Yes thats exactly what I'm doing, but I just figured out the sections behind section 3. I cut the tubing for the rear of the plane and will notch and tack it sometime this week, the only thing Im having trouble with now are the sections in front of section 3. I have the section 1 and 2 rectangles already made and welded.

 I am with Dave here,  Mr. Ultra, other than the front station (motor mount or nose) how are you intending, to include these squares to your lower longerons?

I was thinking of continuing to weld the aft section like most people do with the plywood table and jigs and then notch the longrons and weld them to the squares.




Once I get the front engine mount square and rear 3/4'' tail piece welded to the longrons I will have the basic shape of the lower frame and then I can jig it up on a table and continue to add pieces. I'm short on space and I was thinking of making the first few cockpit segments separately then welding them onto the longrons.


I ran out of tubing for this week so Ill try and take some pictures to better explain what I'm going for here.

[Dan_]

You might want finger patches where you fit the longerons to the square section...

[ultra]

I've decided to start sticking to known methods, I finally understand how the longerons are supposed to be laid out. 

I went out and got some 2x4"x16's from home depot...and drove back during rush hour downtown with it sticking out my rear which was fun. Made a nice work table for the fuselage today as well.

[Dave Stroud]

Longerons are supposed to be the full length of the fuselage according to any airplane I've seen built. Maybe do a little research before you patch yours together. I've checked Bengelis' books and AC43-13 and they don't specifically say that longerons should be full length but common sense seems to. Your number one station is so far about the only thing built according to plans. Your no. two station should be built upwards from the lower longerons as would number three. Think a bit about it. You can use the steel shown in your pics for other areas.....not much waste to worry about.

You seem adept at delivering long stuff with a short vehicle :-)  Brantford's not far away. Get over there ( to ACS) on a Saturday and get enough for full length longerons. You haven't wasted much and there's still time to do it right.

There's also plenty of examples of LE building showing the process on Youtube. There will be some bending needed to make two mirror image lower length longerons. If unsure how to make the bends, just ask this forum. It can be easily done without kinks.

[ultra]

Longerons are supposed to be the full length of the fuselage according to any airplane I've seen built. Maybe do a little research before you patch yours together. I've checked Bengelis' books and AC43-13 and they don't specifically say that longerons should be full length but common sense seems to. Your number one station is so far about the only thing built according to plans. Your no. two station should be built upwards from the lower longerons as would number three. Think a bit about it. You can use the steel shown in your pics for other areas.....not much waste to worry about.

You seem adept at delivering long stuff with a short vehicle :-)  Brantford's not far away. Get over there ( to ACS) on a Saturday and get enough for full length longerons. You haven't wasted much and there's still time to do it right.

There's also plenty of examples of LE building showing the process on Youtube. There will be some bending needed to make two mirror image lower length longerons. If unsure how to make the bends, just ask this forum. It can be easily done without kinks.

Ah I see, well I guess Ill have to make some time to watch some videos, I was worried the butt joint welds on the longerons would be too weak but on the upside I can still use the $150 worth of 4130 here.

Do you think I could still reuse the number two station if I hack off the lower bar and notch it to fit the new longerons? Thanks for the advice.

[Dave Stroud]

Do you think I could still reuse the number two station if I hack off the lower bar and notch it to fit the new longerons? Thanks for the advice

My upper cabin is full width so I did go one continuous piece from the longeron up to the top so I won't comment on your question. Check the plans and do some research, Amigo.
Other builders may chime in here and say what they did.

[scottiniowa]

Ah I see, well I guess Ill have to make some time to watch some videos, I was worried the butt joint welds on the longerons would be too weak but on the upside I can still use the $150 worth of 4130 here.

Do you think I could still reuse the number two station if I hack off the lower bar and notch it to fit the new longerons? Thanks for the advice.

Time spent learning about what works, is well spent..  You were worried about something that has been done since the 1920's?  I don't think I understand that worry, but that's ok.  Like stated by others, you are not out much as of yet, and would have been out a lot, if you carried on.  So this "learning" is all good.

Your above question- Do we think you could reuse the #2 station if you cut out the lower bar and then notch?   I suppose if you gave exact dimensions of what you think you might end up with, we could then give you an answer.... but presently it would have a hard time going past - "maybe"  

Looks like you found room for the table. so now will have room for the fuselage after all.

Best of success.