A Gutless challenge - Fisher’s mighty F7-U3 M. Slats, rivets, fasteners … making slooooow progress.

[HubertB]

Not a lot of apparent progress to report, but some I feel pretty smug about...

A bit of background. Fisher seem to have completely forgotten one aspect of the Cutlass, that is the device that holds the arrestor hook in place (or if it was included, it is not in the parts I have, nor apparently in the instrcutions, but then some small details have been overlooked in the said instructions).

This is what it looks like IRL. The photos are lifted from an IPMS NL walkaround, but beware that the F7U-3M displayed seems to have been cannibalised, or vandalised, over the years, and not every component is still present on this airframe.

 

And this is my rendition of it, adding a few pieces that seem to make some mechanical sense, but are apparently not on the walkaround pics. The whole is less than 1 cm long, if you wonder ... I quite like my springs, made from 0.2 mm tungsten wire coiled around a 0.5 mm brass rod 

 

A few hours' work, not perfect, especially the alignment which is slightly off, but "good enough for govenment work" as the saying goes.

In the meantime, I have started repairing the rear of one wing tip, which has been damaged in all the handling the Cutlass has endured so far.

And the fins are now glued in place. Next should be mating the front and rear of the bird.

TTFN

Hubert.

[Martinnfb]

Labour of love 👍

[GusMac]

Looks great Hubert. Certainly a helluva lot better than most government contractors here could manage. 😁

[Peterpools]

Hubert

Brilliant - awesome work on the missing arresting hook details.

 

 

[ScottsGT]

I’d be in a straight jacket by now if I tried sinking this much detail into my build.  Hell, I’m almost there as it is. 

[CANicoll]

Nice work and on the research as well...  Can't imagine there are that many surviving Cutlass's out there for reference...

[HubertB]

1 hour ago, CANicoll said:

Nice work and on the research as well...  Can't imagine there are that many surviving Cutlass's out there for reference...

There are seven surviving airframes, most of which have been used as gate-keepers and have rotten consequently. 
The pics I posted are from a F7U-3 displayed at the NASM in Pensacola, and features many bogus features and / or missing components. It’s (wrongly) tagged as a F7U-3 M.

I have used other pics for some detailing, like the landing gear bay, of BuAer 129554 (a F7u-3), which was supposed to be restored to flight condition. It has changed hands many times, and is now in Phoenix, AZ. I don’t know if it will ever be finished to flightworthy condition, bur whereas the hydraulic system could be updated to modern standards, and thus alleviate one of the main issues that plagued the Cutlass, the question of the engines would remain, and of the fragile front landing gear strut … It’s still the most reliable source for detailing the kit

Hubert

[CANicoll]

Have you tried a web search on "7U Cutlass blueprints"?  I saw a lot of drawings, but not sure if any of those would be helpful to you?

[HubertB]

20 hours ago, CANicoll said:

Have you tried a web search on "7U Cutlass blueprints"?  I saw a lot of drawings, but not sure if any of those would be helpful to you?

Well, thanks for the tip, Chris. I am usually wary of drawings, as they can sometimes induce some mistakes, and most of these are no exception.

But it yielded some pics of the plane I intend to model, which I had not found hitherto, and will prove invaluable 👍 !

Hubert

[BlrwestSiR]

Very nice work on the tail hook mechanisms there Hubert. 

For small springs, I've found that a number of Japanese companies make them in various diameters and colours. Wave and T2M both come to mind. I think GSI does some as well. I'll grab some pics when I'm at my bench. 

[BlrwestSiR]

Hubert, I finally found my stash of springs. 

As you can see, they come in lots of diameters and black or silver. They're very flexible and I use a set of nippers to cut them to the desired length. 

[HubertB]

Whilst I was 3D-printing some parts for the Potez 25 TOE in the "Sandbox" GB, I also added on the plate some acccessories for the Cutlass, namely a tow bar, two wheel chocks and a boarding ladder.

I will probably revisit the design  of the tow bar, that looks a bit skinny now that it is printed.

 

The Cutlass is on the back burner whilst I focus on the Potez.

I had a tough time smoothing out the wing slats, as Fisher's design is less than optimal in the area, IMHO.

Now that I have revived my 3D-designing and printing skills, I may have a go at redesigning the slats and their struts as an integral part. I had to cut off the struts from the kit in order to smooth the slats recesses on the wings, and, although I have already done some new struts using plastic strips, I am not keen on smoothing the inside of the slats and am not 100 % sure I can obtain a solid link between the plastic struts, the wings and the slats …

Hubert

[Peterpools]

Hubert, amazing work as I only wish printing was in my future but being realistic, it isn't.

Looking forward to the Cutlass making its return to the bench after the GB. 

[HubertB]

Resuming operations ... in slow motion ...

Now that I have finished my entry in the Sandbox GB, and my small interlude with the Rutan Quickie, back to finishing the Cutlass.

I had left it on a frustration, i.e. the wing slats area... The way Fisher has chosn to represent them makes modellers' life a bit difficult. Part of the slats' "recess" on the wings is molded integrally with the wings, and then you have to glue an insert including the slats' arms in a slot in this area. It would be all good if the parts - the wings on one hand and the part-fairings with slats' arms on the other hand - were closely matched, with little adjustment, sanding and filling necessary. Alas, this is not the case (it may also be partly because I started the kit 10 years ago, and the resin has continued to evolve, and shrink in some places). So you end up with at best some nasty seams to fill and sand, and at worst with a step betwen the two parts, that needs to be filled, than sanded. and all of this with the slats' arms in the way 😡 !

In the end, I decided to go for a more radical solution, in three steps :

1) remove the slats' arms, sand and fill to have a smooth base

2) redo the slats openings in the smoothed leading edges. I had a bit of operator's error in their placement, so had to re-fill and re-do some ...

3) design and print some new slats, integral with their actuating arms ...

Here is the result of this work. It does not look nice, but is in fact very smooth with only very minor blemishes still to fil and sand

 

The small fairings on the top of the wing, that match IRL some slots in the slats, have been re-done with some plastic strip and smoothed with the wings' upper surface. The slats recesses were also accentuated to have a more visible separation with the wing's upper surface. It was a tedious job to scrape them whilst keeping a straight line ...

And the newly-designed and printed slats, already primed and sanded to achieve a smoother finish than the raw printed appearance.

Whilst I was in the surface treatment phase, I decided to do some extra work, which then pushed me in slow motion because I am definitely, with hindsight, not a fan of it : redo the structure lines which have been sanded away here and there, and then add some rivets ! I will go for a VA-83 NMF finish, and the rivets are sometimes faintly discernible. Fisher's resin is very hard (probably also because it has had 10+ years to cure some more) and riveting with a pounce wheel requires a significant amount of pressure to achieve even a small impression. I soon found out that holding a ruler with one hand, and applying pressure on the pounce wheel with the other hand was just too impractical : you need to move slowly to impress the resin, and the rule slips, or does not hold when taped in situ. So in the end, all the riveting was done free-hand. Some lines are totally straight, but then close examination of the pictures showed that it was also the case with the 1:1 aircrafts. There was no CNC machining back in the early 50's !

Anyway, some samples of the riveting work. It will be attenuated when I prepare the surface with steel wool for priming. Only time will tell - and show - if the hours spent were woth the aggravation ...

 

When this was done, came the time to finally match the nose and main fuselage !

The fit of the Fisher kit is this area is challenging, and trials showed that some pressure would be needed to ensure that the fuselage parts matched both on the top - that was relatively easy - and the bottom, where there was a gap to eliminate with brute force

But nothing that epoxy and a heavy duty clamp can't address :

When the clamp was removed after a few hours for the epoxy to really set; the top had a small joint and minor step that was easily filed away (here with some Mr Surfacer 500 to better see what remains to be sanded and smoothed :

On the bottom however, there was still a step between the front fuselage and the rear one (but no seam / chasm to fill)

 

 

As the front fuselage has the front LG bay going to its end, the step has to be filled on the rear fuselage, rather than filed on the front fuselage. And as I will need to reinstate some panle lines and rivets, I wanted a hard surface. So, after afew minutes with CA glue and Colle 21 "magic dust", the main of the step has been filled, and the profile roughly re-established. Here as well, I have slathered some Mr Surfacer 500, so the pic is still ugly, but the bulk of the correction xork is done, and now it is just a question of sanding and finishing ...

 

And that is all for now. I should be able to move forward with a brisker pace, now that the essential part of the tedious jobs is behind me.

Hubert

 

 

[Landlubber Mike]

Looking fantastic Hubert!

[HubertB]

Compressor stall … without firing any gun.

 

I have to say that the combination of issues with the slats and the re-engraving of panel lines, plus the decision to add riveting proved to be somewhat of a mojo killer on the Cutlass. Or at least a driver of procrastination …

Which means I have not spent a lot of time at the bench in the last two weeks, or not as much as I could have. I compensated by more reading, but it was Sci-Fi books like the 3-body problem trilogy or « Ball lightning », also from the same Cixin Liu …

Still, I did some progress on finishing the surface preparation, which culminated with the gluing of the front windscreen, a necessary step to avoid any more sanding after priming, as it is not a drop fit that goes without any fitting and sanding …

So, this morning was the time for priming. But, like the Cutlass initially, when the guns were fired, I experienced a compressor stall ! Or, more precisely, a burst pipe; only it’s a pneumatic one, not a hydraulic one, as it happened so often with the Cutlass … The pipe that connects the pressure gauge to the tank of my airbrush compressor had a cut at the level of one connection nut, and burst. So the compressor is now literally stalled, until I can install some new pipe, which I have already ordered.

No pic to show, as there is not any interesting one to show, so more progress some time in the future …

Btw, I had ordered and received the following book. Interesting reading, and some pictures I had not seen before. And it has somewhat changed my mind on the reasons of the failure of the Cutlass. Yes the J-46 was a poor engine, as Westinghouse tried to implement the ancestor of modern-jet engines FADEC, and it was just to innovative for the time’s technology (remember that FADEC development problems nearly killed the A-400 M program ?) ,  and had an insufficient military thrust, but the main issue was the lack of proper transition training for the pilots of the time, coupled with the specific problems of straight-deck aircraft carriers. Transition training led to the creation of NATOPS (and the Cutlass issues were a key driver behind this new approach) and the development of a twin-seat swept-wing fighter, i.e. the famous « Twogar ». And the accident rate of the Cutlass dropped dramatically, at levels lower than other contemporary Navy Fighters, with the introduction of angled-decks carriers.

More when possible …

 

Hubert