Bob Jen's Mossie VR 796

Hmmnnn…interesting, but a long term, Museum based, grounded Mossie kept in the right low humudity enviroment could well be OK even after all this time perhaps…will we ever know????

On this basis I wonder did TFC ever approach the Norweigan Museum that got the ex-Hendon T.3 about doing a swop…..?

After all, the TFC T.3, I suspect could have been rebuild to an acceptable standard as a static museum piece to exchange with a ‘complete’ example that might have been easier, cheaper and quicker to return to the air……a win-win situation possibly..?

Again, we’ll never know I suppose…….:confused: :rolleyes:

I guess the real issue here is that there’s not enough demand for someone to invent a way for NDT glue joints in wood, so we have to do without. I’m guessing it’s cheaper to rebuild any old wooden glued structures, and little demand for preservation of high structural loading wooden items. (If there was demand, then there’d be the technology, and MAM ect would be able to use it – does that make -speculative- sense Bruce?

Rob’s point about modern composites is interesting, but as has been said, the ‘guarentees’ with modern bonding are a world away from W.W.II casien(?) glues.

Modern glues will cheerfully do the job – better than the wood, but you then end up with a replica ‘grandfather’s axe’ situation.

Something I’ve noticed is that flying Mozzies kept flying very cheerfully – byut after being laid up for a period, they seemed to have questions raised about the glue. Is it a) it’s not broke so no fix required, or did flying them keep them young(!)?

Cheers

Perhaps the long term future of such aircraft – if they are to be airworthy, is new build airframes using as many original metal components as possible?

The Mosquito + many other wartime aircraft were not designed for length of service ,they were’nt expected to still be flying 50/60 years after being built.
I suppose this was not a problem envisaged when building the aircraft and the glues to hold them together.:(

Originally posted by Ant Harrington
Thanks Galdri,you’ve confirmed what I was thinking already.So if the strength of the glue HASN’T been verified,how can Bob’s Mossie be declared airworthy?I know it’s PROBABLY ok,but if there’s no garauntee that the wing won’t fail in flight it seems a little foolhardy to fly her. :confused:

True, but, if say the BAe Mossie hadn’t crashed and was still flying today with the BBMF, there would be no guarrentees of the glue on RR299, or indeed there wasn’t up untill her tragic demise a few years ago, or indeed on either of the then airworthy B.35’s now grounded in the USA, but airworthy until the mid ’80’s and early ’90’s….:confused:

Granted, and I did understand that.

So is this aircraft going to have to be “unglued” or is that “deglued” and a new bonding process applied?

Is that possible, or is she being restored for static display only?

Even if only static, what are the chances of something dropping off or peeling apart sooner or later!!??

You are not entirely correct there RobAnt.

True, that many aircraft today use bonded parts, that is, they are glued together. The big difference is the quiality of the glue. Most, if not all, glues used to day are actually as strong, or even stronger than the surrounding structure (talking wood here) and they have been improved over decedes to extend their live. Many of the glues made to day can reasonably been expected to out-live the wood around them.

However the glue used during the war and well into the 50’s was, well it has to been said, rubbish. It was good enough when fairly new, but it has a tendency not to age very gracefully! When the glue is ageing it starts to crystalize and looses its bonding qualities over time. This is a problem that has been known for decedes, and is, I think, the primary reason that so few of the wooden aircraft like Messengers and Proctors are about. When this problem started to appear for real in the 60’s, these aircraft were simply scrapped, as the cost of re-glueing was at the time astronomical and the aircraft cheap and old.

Maybe some can correct me?

Rob- The secret in a lot of cases is the type of glue used and the quality inspection methods of the builders. I was recently talking to a guy about postwar Miles products and they certainly had some problems with the glues used and methods of inspecting
the quality of the finished product even when brand new.

But surely this must be true of all aircraft with bonded parts?

Most aircraft built today would use such techniques, I believe.

Thanks Galdri,you’ve confirmed what I was thinking already.So if the strength of the glue HASN’T been verified,how can Bob’s Mossie be declared airworthy?I know it’s PROBABLY ok,but if there’s no garauntee that the wing won’t fail in flight it seems a little foolhardy to fly her. :confused:

To answear your question Ant,
It has not been verified. It is impossible to check the strength of a glue joint without tearing the joint apart! Then you would have to reglue the entire aircraft again anyhow. I do not know the complete story of this aircraft but I do not think it has been completely reglued.

Some of the joints might be obviously wrong, completely loose, but others might LOOK right on first inspection but when using ‘destructive’ testing (taking the joint apart for re-glueing) it will become apparent that it does not neccecarily have the required strength. I’m battling the glue problem myself in an old aeroplane and I know it can get quite fursturating at times.

Hope this helps,
Galdri

So if VR796 hasn’t been resparred,how has the condition of her original glue been verified?:confused:

Neilly,

Yes, that would be great.

I am having a clear out at the moment, and have some stuff here that I am sure would interest you, including A&AEE reports for W4050 and others. Would you like to borrow??

There has been much said about HML over the years, including that the fuselage halves were separated – also apocryphal!

Cheers

Bruce

Hi Bruce,

Looking at the picture , closer, it would seem you’re most certainly correct. I thought I’d read somewhere that, when Ed Zalesky was restoring her, he’d found an ex-dHC employee who’d worked on Mosquito wing spars. Perhaps in the mists of time (& a crap memory) I misread the article.

Do you want me to send you the other pictures, that my friend sent?

Happy New Year,
Neilly

I dont think the aeroplane has been resparred – If you look at the last picture, you will see the ESA (Esavian) Inspection stamp on the spar web, behind the throttle tubes. In order to respar it, you would certainly have lost that – and look how carefully it has been preserved.

Cheers

Bruce

Hi Ant & Bruce,

I seem to recall, that VR 796 had a new wing spar made for it. The Mossie was partially restored prior to Bob Jen’s buying her.

Neilly

No, we have a complete survey of the aircraft, including the wing spars.

What we cant test is the glue – we know its in there, but we cant determine how well it is performing.

We did a lot of work on looking at methods of Mosquito inspection, but unless there is the will and the money to start the restoration to flying condition (and finish it!), there is no point going any further!

Cheers

Bruce

Thanks Neilly,nice photo.:) I presume you’ve been following the restoration updates in Aer*oplane recently?Looks like Bob is doing one hell of a fine job with her,it’ll be great to see her fly again.I don’t mind what colour scheme she wears,but if she were mine (we can dream can’t we??) I’d probably restore her in Spartan colours,being as the Spartan Mossies played such a key role in mapping and surveying the Canadian territories.
Just one question-how has the condition of the glue joints been verified?The TT.35 at London Colney was surveyed a couple of years back,as many here will already know,but they had to give up when it came to surveying the wings because there was no non-destructive means of testing them.