P51B Mustang (Blue nose)

by scottie | May 18, 2014 | (7) Posted in Projects

I had to think seriously about sharing this article,yes in my opinion I built a sweet looking plane but the maiden  didn't end so well.I have no flight footage,only pictures,a damaged but not lost plane... and am more than a little frustrated !!

So why share then ?  Well if like me,you consider yourself a Scratch Builder or even want too start Scratch building then this article is for you.I've been Scratch Building planes for nearly 2 years and the thing about this hobby,probably the most frustrating thing I have learned is you are more likely too have far more failures than flights when you are building an unproven design.

Look on You Tube,forums,anywhere really and you will see hundreds of successful maidens....this doesn't happen without practice,just remember every process is a practice for your next build.

So onto my build....

  The P51-B

Wingspan 1150mm

Fuselage 1000mm

AUW 1330grams

E-Power BL2815 Brushless Outrunner Motor 1400KV

80Amp ESC

4x E Power 8.5g micro servo

2x E Power 20g micro servo

3 blade 11x8.5 prop

3s 25c 2200mh Gens Ace

There isnt really any build shots,but I will show what I got :)

 Along side a Spitfie for size comparison

 I even achieved the elusive leading edge on the wing,not something many have tried too recreate.Working flaps are also included :).

Control surfaces via 'Snakes'...Shall cover them later...!!!

Battery access

Canopy

The inspiration....

Painted....

Double skinned tail surfaces....

 

 

So did she fly ? perfectly,even the CG was spot on then after roughly 2 or 300 yards she went down,belly landing on the road and stopping when she hit an imovable object :(

The cause....a faulty piece of kit...

This is the Elevator control snakes,it broke right behind the alloy insert causing me too lose control :(

The damage wasn't too bad to be honest,however I do need too redesign my tail surfaces and think about better linkages

The strange thing is I cant figure out how the tail sheered across the foam like this,there is no damage too the tail or underside of the fuselage and it never hit anything upon landing...or well ....crashing :(

The only damage is the control snake that snapped ??

Oh and I bent the motor shaft....but all in all this bird will fly again.And when she does ....there will be video :D

I guess this isn't a typical article showing resounding success,it's more of a sob story :) but one I'm sure many of us have experienced and no doubt many new comers to the hobby shall too.

The moral is tho things like this do happen,yes it is frustrating and yes it does make you wonder why bother sometimes.Then the day comes when your design,your build,your work flies off into the sky...then lands successfully.This is the reason we do what we do....

It is an incredible memory :)

Thanks for reading

Scottie

P.S.

Since I wrote this article,I've made another fuselage,the mk2 :).

It flies,build article too follow but for now a happy ending after all.....

the video......

http://youtu.be/URjMfs0OpQo


 

 

 

COMMENTS

alibopo on June 30, 2014
Hi - bummer, but nice flight video on the rebuild! I reckon your tail damage is what I would call inertia damage. The weight of the horizontal stabiliser was sufficient to cause that damage - when the rest of the plane stopped moving suddenly, the Horizontal Stab. wanted to keep going. You've got a nice sharp corner in there to concentrate the forces, and that's an 'invitation' for a crack to open up. Once it starts to open....
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scottie on July 1, 2014
Hi,yeah it was a bummer to say the least.....I puzzled over that for a few days then just binned the plane and built another 1.
I decided it wasn't worth the effort to repair it,the current version has been 'crash tested' so to speak and the tail again has shown itself as a weak spot although not in the same fashion as the 1st crash.....needs a little tweaking yet :)
And thanks,the rebuild does fly nicely ,the 1 I built for my mate flies better than mine :(
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alibopo on July 2, 2014
I might revise my initial thoughts on the 'failure line' - it looks suspiciously like it runs along the edge of where you drop from double to single thickness foam board. That double-layer system looks great, but the double layer stops against the fuselage. You've created brilliant additional strength and stiffness on the outer part of the H.S., then 'strategically weakened' it at the point of greatest 'need' by dropping the x-section to a single layer. OK you get a nice 'location slot' for fitting the tail to the fuse, but if that double layer went al the way to the centreline, this critical area would more than double in strength. Even if the centreline join was a little messy (which I doubt, considering how great the rest of the build looks) it wouldn't matter, as it wouldn't be seen. :) Any time you make a dramatic change in material thickness, you introduce a point of weakness where forces concentrate. A single layer surface will tend to flex/bend uniformly across its length, but the step from double to single effectively becomes a 'hinge' and even small movements will all concentrate here. If you don't fancy a redesign, how about adding a skewer or two sandwiched into the H. S. as you fold it up?
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scottie on July 2, 2014
Yeah you are right.Well at least I concur ,your theory is sound and even as we speak the addition of a 3mm carbon spar is now included in the H S of the mk2 (you can see it in my P51 build article.
Very nice spot btw on how the structure of the tail was used to seat it on the fuselage,I did actually put a wedge on the inside of the fuselage once the tail was on specifically for that very issue,I knew the tail was weak at that point and did try to compensate,I've just never seen a break like that before...we learn something new every day eh :)
cheers for your input,it is appreciated.
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JamesWhomsley on July 1, 2014
Nice to see you got this article finally published! Love how you built the canopy with all those struts etc. Sorry to hear about the maiden. At least it went better than on of my older scratch builds I maddened the other day - Completely destroyed through the hand launch :P Oh well. Looking forward to seeing some more videos of your 51b though man.
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scottie on July 1, 2014
Yep,finally got them published.Too be fair the guys at FliteTest have been kinda busy so it was nice to get a response from them like I did.....need to work on my patience I think :P
The canopy was really easy to build James,its just strips of 5mm FB shaped and glued into place then covered with acetate.
Sorry to hear your madens didn't go too well,never mind mate,I'm waiting for your Vampire build ;)
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JamesWhomsley on July 1, 2014
Yeah well it looks great, well done. Oh and thanks. :) It was an old project anyway, and at least I can now reuse the electronics. I've been working on the vampire today actually, so keep a look out on the forums!
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LordVader on July 2, 2014
Looks great and can't wait for this, like a giddy little boy on Christmas Eve.:D I will be waiting patiently and watching for updates. Thanks for sharing.
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scottie on July 4, 2014
Thanks very much :)
No pressure then eh :P guess I had better finalise my plans

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Gryf on July 3, 2014
Nice job! That canopy's really a piece of work. Sorry to hear about the failure and crash, but hey, it happens. I have yet to get my Bixler2 to stay in the air. ;-)

Gryf
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scottie on July 4, 2014
Thanks , yeah the canopy does stand it apart from others I think,wasn't difficult too do.
We learn from our mistakes...or failure's in this case .It happens - quite a lot for me actually :P
The re-make is holding up quite well...no control snakes this time :).
cheers

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Yogenh on July 27, 2014
I love the looks of it. What plans did you use or did you make your own. I fit is all yours will you share?
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scottie on July 28, 2014
Hi yogenh,
Yep it's my design . I'm still working on this model, it's still a bit tail heavy as it is just now so it's going through a little change in desin and size . Its basically bigger now:-)
As for the plans, it's difficult for me too transfer them too a digital version but I am trying too do it along side ironing out the last of the cg issues.
I really do appreciate the interest out there for my design, I am trying mate ;-) soon as I can, I will make plans available.
Cheers

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Yogenh on July 28, 2014
Just wish that I could do it as good as you. I am not good at making plans. There are a lot of planes that I would like to make. You just do so good!!!! Thanks for you good work.

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rubens on October 13, 2015
boa noite amigo ,gostaria de seu projeto um download para contruir um plano
tudo de bom
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P51B Mustang (Blue nose)