Project planning: MC-5N "SOPMOD Galaxy"

[Diamondback]

Since I'm both a writer and a builder, and I need to put together a fictional C-5 for something, I need some help fleshing out a build plan and aircraft description. SOPMOD is actually a term lifted from an accessory kit designed for battle-rifles, "Special Operations Peculiar MODification."

While the aircraft I'm writing is officially covered as a "testbed for special-ops rotorcraft transport development," it really only has one primary function: to address the long-range travel needs of a very special, one-of-a-kind CH-53E Super Stallion derivative with only minimal disassembly and reassembly (and NO human hands involved) required for load and unload.

Here's where I am so far...

Written only	Write/Build Uncertain	Model Build
KC-5 added underfloor fuel new multimode nose/tail radars total teardown and rebuild with newer, stronger and lighter materials	10' L-500 stretch Laser countermeasures partial C-5C troop-deck removal towed decoys	new 125K# GE90 engines underwing drop tanks tip-tanks w/buddy-stores C-5C "petal" rear doors

The "uncertain" column is things I'm not sure about modeling, or if they just stick to the text.

Assumptions and questions:
1. Part of the mod package is a group of arms in the upper hold equipped to remove and replace the MH-53N's rotor blades--given that the MH-53N's onboard computer is a human-level Artificial Intelligence, it is also going to be flying the MC-5 from its parking space in the hold. Question: does the aircraft have to lose 100% of the troop compartment to make room for the rotor-head and top of the folded tail, or is it possible to keep some of the forward and/or outboard portions?

2. We're going to need some additional sensors to give that 75-ton "whale" of a pilot equivalent situational awareness to a human flight crew. Do I go with single or dual LITENING-type imager "balls" for part of it, or just go with something like an F-35's DAS and EOTS systems (albeit with both upper and lower arrays), or both?

3. Given that the redesigned MH-53N's mission has been redefined as "strike transport" (combined transport/gunship, kinda like a Hind but can do both at once instead of either/or AND pack a much bigger punch), this monster is going to need some defensive stores, preferably concealed (given those 3000-gallon drop-tanks, maybe just use two on each wing for fuel and one as a missile pod?), and its main cargo is probably going to want to add some Reach Out And Smack Someone capability. If the "weapons pod" option is employed, perhaps the lower half the pod could be used for bombs and the top for missiles. Perhaps splice two B-52 tanks together into a 4500-gallon store for each hardpoint, which would allow more armament room too? The main rule here is any weapons have to be concealed until they're being readied to fire.

4. A would-be-nice goal with this aircraft is, with the MH-53N fully loaded and aboard, to be able to close most of the speed gap between a C-5 (top-out at 579mph/932kph) and the Gulfstream 550 the bird's human teammates fly out on (660mph/1062kph) and also the range gap (5940mi vs 7762mi). How close would be plausible?

5. I'm considering an option to add a B-52-style pylon between inboard engine and fuselage for more overt-action, "hunt the poor S.O.B. target down, stuff him into the Hurt Locker and weld it shut around him" situations. Thinking to lift yet another B-52 part here--is there room and weight for two sets, or just one, or is there some better way of racking ordnance for those "Bend Over, Put Your Head Between Your Legs and Kiss Your Arse Goodbye, MF'er" cases?

Anybody out there feel like throwing in guidance  to refine things or ideas to help flesh this monster out? Yes, I know there's already a C-5 thread that I started--that one was for general discussion of the platform, this one is specific to a single member project. Once things are figured  out a little more... well, I'm looking at 1/144 (Otaki or Anigrand) and 1/700 (Pit-Road; bonus, I can actually get an "MH-53N" in this scale since the Pit-Road 1/700 Pave Low is a WHIF of MH-53J/M nose on CH-53E airframe) options, so the next phase would be determining options for detailing each kit.

[scooter]

Assumptions and questions:
1. Part of the mod package is a group of arms in the upper hold equipped to remove and replace the MH-53N's rotor blades--given that the MH-53N's onboard computer is a human-level Artificial Intelligence, it is also going to be flying the MC-5 from its parking space in the hold. Question: does the aircraft have to lose 100% of the troop compartment to make room for the rotor-head and top of the folded tail, or is it possible to keep some of the forward and/or outboard portions?

Ditching the entirety of the aft would be the easiest, and most realistic to allow the rotor head to remain in place.  As you can see from these shots, the rotor head is removed for clearance.

[PR19_Kit]

'Guppy-ise' the C-5...................

[Diamondback]

Right, one also notes on that Pave Low the entire sail and transmission are gone too. 'Kit, the problem with Guppying is it stands out like someone who's just taken a Chuck Norris Roundhouse Kick in the balls... part of the goal is to keep things more "you have to know precisely what to look for." C-5 with external tanks, well... not that far of a leap for extreme-range applications, especially if it's acknowledged as having part of the KC-5 package for trials.

[zenrat]

Can't help with any of your questions but these pics put me in mind of a python swallowing a rat.

[PR19_Kit]

OK, An-225 it.

Make it longer so the guys who were on the upper deck get to travel on the ground floor and the -53's rotor can hide in their old floor.

[kitnut617]

OK, An-225 it.

Make it longer so the guys who were on the upper deck get to travel on the ground floor and the -53's rotor can hide in their old floor.

Actually Kit, that's more or less exactly what they did when they built the C-5C, they removed the upper deck floor at the rear so they could get a ballistic missile in there, just looking at the Signal/Squadron C-5 in Action and the conversion was so a very large skid could be loaded, called a Space Container. The rear doors were modified too.

[Diamondback]

Kitnut raises a good point--the Space Cargo Mod (aka C-5C) was my start-point for planning, and adding a 10' cut-and-splice stretch as proposed for one of Lockheed's L-500 civilian freighter concepts was step 2. This thing ain't gonna have live pax/crew aboard very often and when it does the numbers should be few enough for the flight-deck and crew-rest area to be more than adequate "meat locker" space.

Then again, it would be an advantage to air-freight the entire mission package on one bird for its "official" role... the backstory I've written is that Lockheed built one civilian L-500 demonstrator after getting a few orders, then Boneyarded it when they didn't add up to enough to justify production, which is how this bird finds its way into private contractor hands--after 40 years of paying storage costs and cannibalizing it for parts I figure LockMart let it go for not much more than scrap value plus costs of getting it into ferry-flight condition just to be rid of the white-elephant.

[PR19_Kit]

The pax could sit INSIDE the H-53, it's not going anywhere and it has got seats installed. 

[sandiego89]

. well, I'm looking at 1/144 (Otaki or Anigrand) and 1/700 (Pit-Road; bonus, I can actually get an "MH-53N" in this scale since the Pit-Road 1/700 Pave Low is a WHIF of MH-53J/M nose on CH-53E airframe) options, so the next phase would be determining options for detailing each kit.

Quite a project!  We really need an affordable 1/144 or 1/200 C-5.  

I can offer a bit, the 1/144 kits are super rare, and super crazy prices, I would gag if I chopped one of those up, but your money...

The 1/400 diecast models are good, and might be a better starting place if you just want to do external changes like paint, weapon pods, etc.  They are solid metal however and thus would be an immense challenge to reshape, lengthen etc.  

The 1/700 Pit Road examples are a great kit, but getting pricy as well.  But even the C-5 is small in 1/700.  See below for some examples of my beat up spares bin C-5's.  Out of the box they are designed with closed doors and clamshell nose.  They can be opened up as is my C-5 in Euro One camo.  CH-53E's in there for scale as well.  

My thoughts are that you would delete the rear troop compartment (like the the C-5C), and this would leave enough room for the rotor head on the CH-53.  There appears to be enough room behind the main spar pass through of the C-5 for the CH-53 to be behind the wing. If you have the 53 in the rear part of the cargo bay, you will definitely have to come up with a fix for the top part of the ramp, that folds up out of the way to allow loading. 

This would still leave the cockpit and courier cabin atop the forward cargo bay intact if you have your live crew aboard. Plenty of room.   

I do not see a way to realistically leave the tail rotor unfolded.  Just too tall, and would interfere with any type of ramp/door.  

Width is also an issue.  The CH-53 sponsons barely fit inside the hold (as per the pictures others show), and external fuel tanks or weapons outboard the sponsons have to removed or fold up someway.  

If you go with a 1/700 model, many of the things you mention like radars, sensors, engine upgrades, decoys etc would not even be noticed in that scale, just too small.  New pylons could easily be fitted on the wings, but would detract from you stated goal of increasing top speed of the mother ship.  As the forward part of the cargo bay would be empty, perhaps just go with a bottom or side weapon bays here.  Plenty of room.    

PitRoad C-5's and CH53E's, all in 1/700

 

The belly and ramp area of a C-5.  I have cut this open.  Kit out of the box, the ramp is sealed shut.  

The C-5 cargo area is just large enough for the 53, but really no room to spare.  



A CH-53E atop a C-5.  I am NOT suggesting such a piggy back placement, just to to show the rotor head of the 53 would appear to be behind the main spar of the C-5, so room if you deleted the rear upper troop compartment.  Note how tall the tail rotor is.  Even if the rear troop compartment were opened up, I think the the tail rotor is too tall.  Suggest keeping the tail fold feature.  



Another shot on my hand for scale.  


 

[Diamondback]

Thanks, amigo--I had assumed the tail unit would be going in folded (possibly a blade or two removed), ditto the batwings at the end of the sponson and the tanks. '53 tail has a power-fold, so I'm not worried about labor on that part. Re weps, I was thinking for normal ops just running with two tanks or one and a buddy-store on each wing--a little more drag, but since we're posting an up-rate of almost triple the power of the original TF39 (125K# vs 43,300#) I figure that can be overcome just with engines--and with the GE90 being more efficient, that will help with range too. .25lb per lb-thrust per hour on GE90-115B vs .313 for TF39, since the -115B has gone to 127K# on the stand I'm assuming that the GE90-125 would use an enlarged version of the GEnx/GE9x fans for extra power at similar efficiency... .25x = .313*43300 = break-even fuel burn at a throttle setting for about 54,000# thrust. Which means about 60% of the engine's capability as "head-room"...

Probably what I'd do if I was gonna build in 1/144 right now would be use the Anigrand fuse as a master to create a mold, then cut and stretch the resulting plug as a new master for a vacform part.

Actually, I too have a couple Pit-Roads sitting on the bench.

[PR19_Kit]

Now if Sikorsky had made the tail rotor fold DOWNARDS from the end of the ramp there wouldn't be a height problem. The tailplane could then just fold flat and the whole device would fit nicely in a C-5 shaped box.

[Captain Canada]

I'm liking this one !

[Diamondback]

I'd swear that somewhere I saw a photo of an Echo being loaded with only the top rotor-blade removed from the tailgroup (note, the Pit-Road "Echo" is a hybrid: Echo canted fin mated with non-Echo flat tailplane), but cannot seem to find it again.

C/C, don't anticipate this too much, it may never make it to the build phase unless a viable C-5 kit (read: "cheaper than Anigrand or evilBay Otaki, and not in an only-thing-that-size scale like the mini from Academy") gets back to market. I've got a ton of builds piling up before this: the F-106 for a now-retired old prof, two NF-15SE's, FrankenProwler II, a Tomcat 21, at least one MH-53N in 1/48 and possibly another in 1/72 (actually, the 1/72 build may happen first)...

[kitnut617]

If you're going with the rear passenger floor removed, there is another way to leave the tail were it is.  You park the 53 nose-wheel on a ramp placed in the appropriate place in the middle of the cargo floor. This would raise the forward fuselage and lower the tail as it pivots around the main gear.