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Author Topic: Martlet Mk.IV  (Read 2885 times)

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Knochenlutscher

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Re: Martlet Mk.IV
« Reply #12 on: November 14, 2018, 03:08:01 PM »

You freed this bird from ingame slot/nation prison to it's own Slot.
How cool is that.  :)

@ LameHawk,
Yeah,...  :(
to be precise it's long ago I did the research, don't remember all, it's 4 up to 5 years since I was
working at this.



showing early british Martlets II's before delivery...
note different hubbed versions of Hamiltons, at a time USN
Wildcats 99% went unhubbed.
This Prop Type looks similar to that used at P-36s.
There also hubbed caps and unhubbed Props existed.


Look how large the IV's hub cap is referenced to a head, the diameter of blades
is questionable, but best I could find. I couldn't find a smaller working of this type.
Although it must be shrinked in 3-D software at parts of blades which I can't.
The Mk.IVs prop looks similar to that of the Hellcat.



USN FM-2s appeared late in war with the hubbed type the Brits went earlier...

Early USN elongated hubbed are very rare in pics, but exists.

Code: [Select]
A flight of freshly delivered Grumman F4F-3 Wildcat fighters belonging to VMF-211, circa November 1941
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WxTech

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Re: Martlet Mk.IV
« Reply #13 on: November 15, 2019, 09:46:46 PM »

I just installed this to my 4.12.2 Modact 5.3 game (never d/I'd before).

Within an hour or so I:
- Updated to my Wildcat standard, using the F4F-4 'pit (not the F4F-3, as here originally.)
- Installed my GM-1 gunsight.
- Copied over from the F4F-4 the improved spinning prop mod (which presents as having thickness when seen from the side), but retaining this plane's higher poly count prop hub.
-  Added a line to the cockpit class setting my expanded 6DoF parameters.

Because I use the F4F and I-16 auto gear mod (gear operated with a single key press, instead of a zillion presses ;) ), I attempted to reduce the number of gear crank handle turns, because it's awful to have this going on *LOOOONG* after the gear has settled into place. I did this successfully for the Wildcat, wherein I set 7 turns to replace the 44 turns previously. But with the Martlet, the handle turn rate is glacially slow. I might have to bring this turn count down to just 2.

Once I'm satisfied, I'll release this update of mine. It will be a full mod, replacing the original.

And I did the same for one of our Martlet I/II mods as well, which will be released.

I don't know if my addition of the new 6DoF limits will have any impact on the compatibility with earlier game versions, like 4.09. To guard against this, I could include classfiles not having this (as well as restoring the stock 44 gear crank turn count, for those retaining the stock manual gear operation.)
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WxTech

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Re: Martlet Mk.IV
« Reply #14 on: November 17, 2019, 12:44:22 AM »

After trying to take off from jeep carriers, the large prop diameter made the process nightmarish. The *slightest* nose down angle would have the prop striking the deck. Indeed the only safe way to make it to the end of the deck is to keep the tail down by a safe margin. Any oscillation to a level condition would usually have the nose dip just that fraction of a degree past level and then--a hop over the bow into the drink is yer fate due to a bent/stopped prop.

So. For the time being I simply disabled that monstrous fan and replaced it with the same one fitted to the earlier Martlet. (Which appears to be the same or very similar to the ones on the stock F4F-3, -4 and FM-2.)

I'm not sure how to set the collision box/disk for the prop, which is the critical part as regards deck/ground striking. I think I could scale the prop model down in a spreadsheet, leaving the hub unchanged. I *may* look into it; but so many projects call for my attention. ;)
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WxTech

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Re: Martlet Mk.IV
« Reply #15 on: November 17, 2019, 11:13:19 AM »

I've commenced looking at the Martlet IV's prop in a spreadsheet. From the rotation axis to blade tip the length is 2.036m (6' 8.2"). Anyone know what the blade length should be? If it was really this long, then take-offs in this bird would have been hairy to say the least.

For the Martlet II, the game's prop model has the blade length (from hub center) as 1.535m (diameter: 3.07m, or 10'), or a tad larger than in reality. Close enough!

[EDIT] Been looking on-line, and found prop diameters for the Wildcat and Martlet of 2.97m (9' 9"). The FM-2 (Martlet VI) went up to 10'.


Sooo... Looks like the 13'+ prop supplied here was simply taken from another bird, like the Hellcat, perhaps. Waaayyy too big! I'll scale down the prop so as to get the same dimension as for the Martlet I/II. The easiest is to scale the whole shebang, because isolating the hub from the blades is more work with a spreadsheet. ;)
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Knochenlutscher

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Re: Martlet Mk.IV
« Reply #16 on: November 17, 2019, 12:59:31 PM »

I took it from a Hellcat when memory keeps me not hanging.
The prop housing must be that size, prop diameter only firmly cut. No clue how to do that. Tried rescaling, but it shrinked the hub too. This one needs a 3-D care to reshape better.

The other 2 hubbed Wildcats probs I took from other Mods too, but appearantly worked from sctratch, only this was a stopgap.

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WxTech

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Re: Martlet Mk.IV
« Reply #17 on: November 17, 2019, 01:32:35 PM »

This is my first time looking at props in any kind of detail, so my comments at this point should be taken with caution. ;)

It seems that the prop clip values here correspond to a prop model orientation where the vertical blade points *up* in the model (as it does for the Martlet II, for example), whereas instead here the model's vertical blade points down. In other words, the clips are out of phase rotationally by 60 degrees (midway between the actual blade tips.)

-----

I've already scaled *everything* to 0.7539 times the original dimensions; that was a pretty quick operation. Now, this also decreased the blade width and thickness in the same proportion! This is probably not the ideal approach overall, for I suspect the blade root might have to be kept essentially unchanged. And as noted, the hub should remain unchanged.

I'll see if it's no great problem to at least isolate the hub from the blades, and thus leave the hub un-modified at its original size....

-----

Three questions about clips:

1) Is it strictly necessary to have the clips correspond to the actual blade tips? I would presume so for reasons of accuracy when considering collisions by other vehicles while parked. But I suppose in practical terms this is a distinction hardly worthy of fussing over. ;)

1) Is there some established convention for clip point listing order, or can they be listed at random?

2) Is it necessary to define a clip for the *hub* tip? I ask because there is none for the Martlet II, but there is one for this Martlet IV. Again, in practical terms, I should think that the small extension of the hub forward of the cowling hardly makes for that much of a difference where collisions are concerned.
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WxTech

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Re: Martlet Mk.IV
« Reply #18 on: November 17, 2019, 03:02:54 PM »

With some creative spreadsheet manipulation I've managed to isolate the hub and the three blades separately. This gives me control over their individual handling.

But what on earth? One blade of the three is comprised of 236 vertices. The other two *each* have 836(!!!) vertices. Looks like lots of needlessly duplicated points, is my first guess.

Doing this by a spreadsheet sure is labour intensive... But I knew that.  :-|
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WxTech

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Re: Martlet Mk.IV
« Reply #19 on: November 17, 2019, 07:14:32 PM »

OK. Success with the static prop.

Next is the rotating prop, a simple task of mating the 'wide' modded spinning disk to the existing detailed hub.

I'm not going to tackle the damaged prop. It would take almost as long to do as the undamaged one (the latter of which has taken about three hours), and moreover its wrecked shape should conceal somewhat the size disparity.


[ADDED IN EDIT] All done and working (except the damaged prop, as just indicated.) A mod pack should be ready to put out there soon (along with the Martlet I and II)...
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