Cowl Fasteners on DH98 Mosquito (and MB5)

[MrSmoothie]

I'm curious about the lower cowl fasteners on the Mosquito -- they look like they might Dzus fasteners attached to a spring steel tab that makes them pop out a little once released. But what is the purpose of the slots to either side?
Also, look at the bottom edge fasteners on the Martin Baker MB5 cowling -- are these the same or similar? Were these standard parts on British planes in WW2?

 

[Airframes]

I don't think they were standard on all British aircraft of the period, and yes, I believe this type were on a tensioned release. Andy ( Crimea River ) is involved in a Mosquito restoration, so i'm sure he can give a much more detailed answer.

 

[gumbyk]

As Airframes said, those are release springs to ensure the fasteners are out of the way once released. Not sure that they were universal, but certainly not uncommon.
Those 'slots' are painted marks either side of the fasteners, which align with the fastener when latched properly.

 

[Wurger]

And an enlarged shot of these for the MB-5

the source: the net.

 

[MikeMeech]

I'm curious about the lower cowl fasteners on the Mosquito -- they look like they might Dzus fasteners attached to a spring steel tab that makes them pop out a little once released. But what is the purpose of the slots to either side?
Also, look at the bottom edge fasteners on the Martin Baker MB5 cowling -- are these the same or similar? Were these standard parts on British planes in WW2?

Hi
I have posted these images before on the forum, they are from my training notes from the early 1970s but most of the fasteners were in use during WW2:

All come under the standard British AGS system (includes nuts, bolts and various other items etc), which has been around from WW1. Various fasteners being introduced at different times and the manufacturer generally choosing the most suitable for their design.

Mike

 

[Crimea_River]

The Mosquito engine cowls used Dzus fasteners supplemented with spring clips to make the fastener pop out of its hole on the engine frame for easier removal. What you call "slots" either side of the fastener are simply marks showing the position of the slot on the fastener for the closed position.

 

[MrSmoothie]

This is fantastic information all -- thanks for the responses.

Now to the MB5 -- I don't see the spring clips. Is it possible they simply added the alignment marks?

 

[gumbyk]

This is fantastic information all -- thanks for the responses.

Now to the MB5 -- I don't see the spring clips. Is it possible they simply added the alignment marks?

They didn't all have those spring clips; I don't know how they made the decision on whether they were needed or not. But I can tell you they make fitting the cowls by yourself a lot easier. They keep the fastener out of the way while you are offering it up.
The alignment marks were fairly common, so its likely that the MB5 only had them.

 

[Wurger]

The enlarged shot of the fastener slots in the airframe reveals that the dzus springs where there though. Just my opinion.

 

[MrSmoothie]

Looking at an enlargement of the lower cowl photo (which is slightly better resolution than the one I had on file), I'm thinking that they painted alignment marks to either side, but also the slot of the fastener, making it look like a single line. I doubt the shadow of the slot would look that dark.

I thought there might be a thread on ww2aircraft.net which just includes photos and other information on the MB5. I did a search but didn't see one. Before I start one, can anybody point me in the right direction?

 

[Wurger]

Here is yout shot of the better quality ..

the source: Martin-Baker MB5 Fighter

And here the enlarged shots of the dzus there. IMHO the black lines are not only the position indicators but also the slots in the screw flat head.

And here the dzus springs that can be noticed nicely through the holes in the frame ...

 

[MrSmoothie]

I found this in another MB5 thread on this website -- unfortunately the URL link is no longer active. I don't suppose anybody downloaded that PDF or knows another website that has it?

Here are some articles from "Flight" magazine 1945 (downloadable as pdf) : the MB-V
http://www.flightglobal.com/pdfarchive/view/1945/1945 - 2363.html

 

[Algernon]

I found this in another MB5 thread on this website -- unfortunately the URL link is no longer active. I don't suppose anybody downloaded that PDF or knows another website that has it?

From my "mini-archive"