De-Suckifying the YFM-1: Building an American Heavy-Fighter

[Zipper730]

The YFM-1 had some ideas that were absolutely insane, but it did have some redeeming features

1. 2-Engines: Supposedly one engine has less installation drag than two, but when power's limited -- there ain't no shame in getting out an extra engine to do the job. The V-1710's also were effective engines that proved highly reliable throughout the course of WWII.
2. Turbocharging: While turbocharging definitely had limitations, it was good if you wanted to fly at high altitudes.
3. Range: If I recall it's range was around 1700-2500 miles and that is valid for an escort plane

This is both a request as well as a personal challenge regarding the ability to straighten out images and make effective photo-manipulations.

Since a photo-manipulation requires a photo, or in this case, blueprints, I have two of them. The first is the more detailed of the two and is courtesy of D.A. Williams, and will probably be used last, though ironically, I think it's the earliest version of the Airacuda.

The second image is courtesy of The largest free blueprint and vector drawing collection on the Internet - 16000 vector templates for sale, and will be the initial starting point as it's the least detailed and easiest to manipulate. It also is a three way view.

I didn't make any of these. These are just a starting point.

The first issue will be proportions, and I'm basically using much of the same things that Witold Jaworski was doing on his page. Straighten the image out, and then make sure everything is of the same proportion.

Any advice will be welcome, such as what size to resize these images to if they're too big to avoid trouble.

 

[Zipper730]

I'm simply reworking the images into front, side, and top

I will probably use the side image first in order to line up everything

 

[Capt. Vick]

Get rid of the twin cannons, put a single one in the nose and make it a puller. Eliminated 2 bodies and the overheating problem.

 

[fubar57]

It will take more than photo manipulations...The flying anti-aircraft battery: The Bell YFM-1 Airacuda had some design issues
Airacuda XFM-1 (Experimental Fighter Multiplace)

 

[Zipper730]

Turns out I'm working with the top image: I've measured the components in pixels since that's what I got

I've also measured the length of other components such as the mid-spar (the line halfway down the wing-chord) to the tip-line (the chord-wise line prior to the wingtip), with the following figures...

Location......................................................................-.Pixel.-.-.-.-.-Coordinates
........................................................................................(X,Y)-.-.-.-.-.-.-.-.(X,Y)
Overall Span:-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-926.-.-.-.018 x 253 - 944 x 253
Forward-Spar to Forward-Spar (Front Boundary):-.-.-.-.857x3-.-053 x 229 - 910 x 232
Forward-Spar to Forward-Spar (Aft Boundary):-.-.-.-_...857x2-.-053 x 232 - 910 x 234
Mid-Spar to Mid-Spar Inner Tip-Line (Front Boundary): 857x3-.-053 x 260 - 910 x 263
Pitot-to-Pitot*:-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-._.882x1-.-042 x 163 - 922 x 164
37mm Barrel-to-Barrel:-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-_228x2-.-369 x 029 - 597 x 031

The reason I put X,Y is that I'm basically lining things up to use the pythagorean theorem to correct for the slight slant on the image. I'm planning to correct that on all of them.


Footnotes
*: I accidentally put 2 instead of 1 on the drawing when it came to space between the 37mm cannon.

 

[FLYBOYJ]

I read through this with an open mind and I really don't think there's really anything more you can do to improve the basic layout, the old term is "you can't polish a turd."

BUT - it is a neat aircraft.

I think you might want to try to make this one work - better suited.

 

[wuzak]

I was going to say the best way to improve the YFM was start again. From scratch.

For the XP-58, the first task is to decide what you want to do with it!

 

[swampyankee]

Like many failed projects, the YFM-1 was designed to a basically flawed concept, so the USAAC had to bear considerable responsibility* for its failure*, but Bell also needed to bear the rest.

To de-suckify:

• require a speed, at all altitudes, at least 15% greater than the specification for the next generation bomber and no more than 10% less than the next generation fighter, i.e., if the bomber is 250 mph and the fighter is 350 mph, the bomber destroyer must do 315 mph.
• limit the crew to two (goal) or three (absolute limit)
• if it's a twin, require a positive rate of climb with either engine out and safe OEI behavior
• it must be capable of all normal fighter maneuvers, including spins, in all loading conditions
• there must be independent and direct escape routes from each crew position
• something better than the M4 37 mm gun for main armament.

The plane I would envision would look like a mid-wing twin, with two high muzzle velocity cannon under the nose, plus either RCMG or HMG, also firing forward. I don't like pushers or twin tails, but that's mostly a matter of taste. Definitely flaps, probably Fowlers.

_--------------------

* The army liked the plane enough to buy it. Possibly,Bell was as well connected as Hughes, but I don't think there were many aviation projects invo!ving Howard Hughes that he didn't screw up.

 

[michaelmaltby]

... how would, in your opinion, would a twin P-47 have performed ... with Merlins?

 

[Zipper730]

I read through this with an open mind and I really don't think there's really anything more you can do to improve the basic layout, the old term is "you can't polish a turd."

Oh the idea is to basically alter nearly everything about the design.

Since the idea involves morphing the basic shape, it still requires basic blueprints that are solid

Like many failed projects, the YFM-1 was designed to a basically flawed concept

That's what makes it so interesting, the airframe had fairly clean lines in some ways, but was built around ridiculous requirements.

1. It was ultimately built to satisfy the desires of several different groups of people which might have been in contradiction
   • Those who wanted standing patrols over extreme speed and climb-rate: While there is an advantage in that it doesn't require as extreme a rate of speed, and a rate of climb, it still should be built to fly at the speeds of standard fighters. I'm not sure what we knew about foreign fighters at this time, but it seems that around this period we were producing fighters like the Y1P-37, which could do 340 mph (it was a flop not because of its speed, but because it had almost no forward visibility).
   • Those who wanted more firepower over traditional fighters: While greater firepower does make sense for bringing down large aircraft (the Hurricane and Spitfire carried eight guns for this purpose, and their proposed successor was to carry twelve), the issue isn't just that you have a lot of firepower, but sufficient performance to actually bring the guns to bear.
   • Those who wanted a bomber-escort: There was generally a sentiment that fighters were not necessary for the mission, but there were some at least, that saw them as inherently useful, even if not necessary. They couldn't seem to agree on what they wanted: Some wanted gunships in the form of bombers that didn't carry any bombs, but carried extra guns, while others wanted fighters that had a rear gunner, and I wouldn't be surprised if some (like Claire Chennault, though I could be wrong) simply wanted a fighter that could simply fly really far; none (though I can be wrong about the pro-fighter group) wanted drop-tanks for the fear that pilots would just punch them off at the start of combat (they didn't seem to get that from climb-out, which burns a lot of gas, up to the start of combat, you have range, nearly for free) and sacrifice any range benefit, and wanted the aircraft to fly the mission on internal fuel alone (which is nice if you can pull it off).
   • Some people had an idea of dropping bombs on bombers as a way to destroy them, even using a device called a petoscope (which would use multiple light-sensors that would react to changes in light and when enough contrast is produced -- a bomber blocking the light -- it'd set off the bomb). The USAAC and USN had developed this idea, though the USN wanted 5.2 pounders, and the USAAC wanted 15-20 pounders. The fact that they eventually went to 20-pound blast-fragmentation bombs seems to basically gel with the idea of some who felt CAS would be best used by aircraft carrying large numbers of 20 pound blast-fragmentation bombs, indicating some intent to make either a fighter-bomber, or fighter with an attack sub-variant (There were those who wanted a rear-gunner for additional protection, defeating Lufbery circles, and this would gel with this idea), such as the P-30/PB-2 & A-11.
2. It wasn't stressed to typical fighter requirements: This makes interceptions easier, and also would be important for the bomber-escort mission. When you consider that even the Beaufighter (which used the wings of a torpedo-bomber) was able to pull decent loads, this doesn't seem unreasonable.
3. The armament was inadequate: The 37mm while brutal on impact, didn't have sufficient muzzle velocity until the M9 came out. That said, the P-38 had a 37mm that was replaced with a 20mm HS.404. I am curious what came of the Hotchkiss 25mm (it was originally sought for the P-38/P-39)
4. It need a crew of 2 at most: One to fly the plane (IMHO all you needed), and the other to adjust the fire-control and pivot the 37mm barrels (worst case).

What's an RCMG?

I was going to say the best way to improve the YFM was start again. From scratch.

Of course, the idea would be to use the basic lines, but otherwise alter almost everything else. I am curious if the variable position barrels was a requirement or simply a way to get around the limits of the 37mm ballistics?

 

[swampyankee]

RCMG = Rifle Caliber Machine Gun

 

[Zipper730]

I've done some estimates and found the misalignment in the image is such a small amount that it has little effect on the length and span of the aircraft (less than a pixel), so for the time being, I've basically drawn a line down the length and span of the aircraft which are color coded (blue when they pass over black lines) and prove to be a useful guide and plan to mostly redraw the image with attention to ensuring the fuselage, propeller and wings are symmetrical.

I figure from that point the objective would be to check the side view and line up what needs to be lined up or re-drawn; then line them up to ensure that their lengths match.

 

[Zipper730]

So, basically I removed everything except the lines and that leaves me with this...

... which indicates the centerline shifts three pixels off which puts the center line in the middle, and the left side is two pixels above the spar, and the right is two below.

Centered nice and good now...

 

[XBe02Drvr]

I don't like pushers or twin tails

Twin tails are generally a major boon to single engine-out handling in a high powered twin.

 

[P-39 Expert]

I don't think the YFM-1 can be de-suckified. It had tons of suck specified by the AAF and constructed by Bell. How would you like to be a 37mm nacelle gunner? "Time to bail out! But wait, what is that spinning behind me? Oh no, it is the propeller!"

 

[XBe02Drvr]

How would you like to be a 37mm nacelle gunner? "Time to bail out! But wait, what is that spinning behind me? Oh no, it is the propelle

Hey, you're only an enlisted guy. You're expendable.

 

[maxmwill]

Like many failed projects, the YFM-1 was designed to a basically flawed concept, so the USAAC had to bear considerable responsibility* for its failure*, but Bell also needed to bear the rest.

To de-suckify:

• require a speed, at all altitudes, at least 15% greater than the specification for the next generation bomber and no more than 10% less than the next generation fighter, i.e., if the bomber is 250 mph and the fighter is 350 mph, the bomber destroyer must do 315 mph.
• limit the crew to two (goal) or three (absolute limit)
• if it's a twin, require a positive rate of climb with either engine out and safe OEI behavior
• it must be capable of all normal fighter maneuvers, including spins, in all loading conditions
• there must be independent and direct escape routes from each crew position
• something better than the M4 37 mm gun for main armament.

The plane I would envision would look like a mid-wing twin, with two high muzzle velocity cannon under the nose, plus either RCMG or HMG, also firing forward. I don't like pushers or twin tails, but that's mostly a matter of taste. Definitely flaps, probably Fowlers.

_--------------------

* The army liked the plane enough to buy it. Possibly,Bell was as well connected as Hughes, but I don't think there were many aviation projects invo!ving Howard Hughes that he didn't screw up.

I've a small question concerning the YFM design itself. Does it necessarily have to be stuck with just the two engines, or, could the tail have been modified to accept a pusher configured engine, with a cruciform tail just ahead of it?

Or would that be too radical a departure from the design?

 

[Graeme]

I'm basically lining things up to use the pythagorean theorem to correct for the slight slant on the image. I'm planning to correct that on all of them.

Not sure why you would need to go down that path to correct the image tilt. Do you have IrfanView? There is a brilliant tool in it to correct any image tilt. Wurger is very good with this - I suggest asking him for help.

 

[P-39 Expert]

Hey, you're only an enlisted guy. You're expendable.

Not exactly the way I would like to go.

 

[XBe02Drvr]

Not exactly the way I would like to go.

Not your choice to make, Soldier!