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sonerai II stretch build question

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dreamerF16

Active Member
Joined
Apr 15, 2020
Messages
25
Location
north carolina
hey all, I’m a new member and just purchased plans to a sonerai 2 stretch, i’m building the whole plane from scratch, 2 questions, in the prints in looks like the longerons are just one long piece although a cut and splice option are available, I would like to avoid the cut and splice option, but every site that I’ve gone to only sells the 4130 tubing in a max length of 9-12 feet, what can I do here? also I’m planning on omitting the turtle deck and just leaving that entire section flush/flat (forgive me if i’m bad with terminology i’m new to this, I’m not sure what that section is technically called, top of fuselage maybe?) and adding a bubble canopy, can this be done and is there any concern/structural issue? I appreciate any help
 
Don't know specifically about the stretch, but the 2 I built called for all 4 longerons to be spliced just aft of the rear seat station. Was 3/4" dia tube ahead and 5/8" dia tube aft.
 
Don't know specifically about the stretch, but the 2 I built called for all 4 longerons to be spliced just aft of the rear seat station. Was 3/4" dia tube ahead and 5/8" dia tube aft.
thank you, so with the splicing method, does the 5/8” tube simple go inside the 3/4” tube and that 1/8” of play is just welded up? that was my main concern about the splice method, wouldnt that be structurally weaker than having 4 longerons that are all one piece?
 
First, it is not 1/8" of play as the 3/4" tube is 0.035" thick, so the inside diameter is 0.75"-0.035 - 0.035" = 0.680". So there is 0.680-0.625=0.045" of "play". Yes the 5/8" tube goes up inside the 3/4" tube a bit, and can be rosette welded in addition to welding the angled cut on the 3/4" tube. The strength of that welded joint will be enough that if the weld were to fail, the wings have already folded. The 3/4" tube will probably add a couple pounds and every pound you add is a pound less in useful load. You already said you can't get tube long enough anyway, so in order to have 3/4" tube the whole length you will have to do a splice as in AC 43-13.1B. That splice won't be any stronger than the splice between a 3/4 and a 5/8 tube.
 
And the top rear portion of the fuselage is called a turtle deck.
Bob
I knew that part, I should have been more specific, if I leave the turtle deck completely off and just have a straight flush top of the fuselage to install a bubble canopy would that effect the structural strength?
 
Just reviewing a few things and came across this post again.
You can weld a rollover bar similar to the RV series of aircraft for a bubble.
You'd need some curvature welded in just so the turtle deck isn't flat. It would look off just flush.
 
I very humbly advise to not stray from the plans unless absolutely necessary. The more changes you make the longer everything takes and you may not get the results you anticipate. I especially caution against changing materials with a "stronger/bigger/thicker is better" rational, as these are well proven aircraft when built to the plans, and adding weight is just not a good thing in most cases.
.
 
The bubble canopy will likely be more draggy than the turtle deck design.... Just like with the P-51 C and D. And you're not likely to see an ME109 on your six anyway.
 
The bubble canopy will likely be more draggy than the turtle deck design.... Just like with the P-51 C and D. And you're not likely to see an ME109 on your six anyway.
As for the P-51, it has been said that the B/C was a bit faster than the D with the cutdown turtle deck and bubble
 
Hi, interesting topic. For one who's head won't swivel past 90 degrees, I'm all in favor of a turtle deck. It has in built rollover protection, easily accessible stowage and adds speed. See Kent Paser book for ideas on efficiency. If you really must see behind, add a mirror like gliders do.
regards
Graham
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Speaking of rollover protection, I built a 2 from 75-80 and never gave it any thought. But since then, I’ve become concerned about it. Specifically, if you do go over on your back in a low wing, even if you have the protection of the turtledeck hoop, hopefully the canopy has not shattered and skewered you in the noggin, but even if that didn’t happen, how the heck do you get out? And what if it catches fire? This has always bothered me.
I’ve been over once, violently, in my first Tailwind. The structure protected me completely, and one door even popped open to let me crawl out.
So does anyone have a thought exiting a Sonerai that’s on its back? Has any Sonerai ever been known to go over?
 
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