AN 225A - the one that is only part built!

This is a thread that will probably never end up with anything but as I mentioned in the Cafe I have started thinking about converting my as yet un flown AN124 into a AN 225. Not exactly like the one that is flying now but rather how the second incomplete one might have looked.

if I had built my AN 124 with a wing joint at the root (as in the full size) the conversion would be simpler as the 225 literally took 124 wings and fixed them to a new centre section. Unfortunately I built a one piece centre section that carried all four engines so I will have to first cut each wing off at the root and then add a new centre section with the two extra engines. Then fix it all back together again to make a bigger 6 engine centre section. At least the removable outer wing panels can be used without any modification.

The fuselage of the 225 is also longer so my 124 fuselage will have to have a section added under the wing to account for the extra wing root chord and another to extend the fuselage ahead of the wing. As far as I can tell the AN 225A rear fuselage and tail would be as for the AN124.

This gives an idea of what needs to be done to achieve the conversion.

As the fuselage of my AN 124 is the largest bit and will only just fit in the car the AN 225 fuselage will have a joint just ahead of the wing. The means it should actually all fit in the car a bit more easily than the AN 124.
On the basis that drawing doesn't actually cost anything I drew out the new centre section to scale to get an idea of what internal structure might be required.

The biggest root ribs are nearly 24" long and over 2.5" deep. That represent an awful lot of printing time!

Searching through the AN124 "spares" box I found that I already have 2 spare drone motors and 4 spare 3 x 3.5 four blade props so at least that aspect is covered.

Given that the AN124 has not flown and has almost zero crash resistance the more I look into this AN225 proposal the dafter it becomes.
The most likely outcome is that after the AN124 maiden there will be nothing to convert. :woohoo:

crazy! (in a nice way)

As I have the time it seemed a pity not to do some printing 'just in case' so there are now two more pylons and motor mounts.

They are identical to the inboard ones on my AN124. They are quite complicated to print with 4 different infill patterns so it took a bit of time to remember exactly how I did it.:woohoo:
Each takes 4.5 hrs to print. The front part of the nacelle will take about the same.
It works and pleasantly smooth running as well.

Only with 3s. In the plane it runs on a 4s.

A picture of the second incomplete 225.

Its been like that for 30 yrs!

Can't they get any depron either? [badass]

Eric wrote: Can't they get any depron either? [badass]

You could always try the new fangled Balsa wood...

Antonov say that about 70% of the second AN225 is complete and it would only take between $250 & $350 million to finish it.
The Chinese were very interested but insisted they wanted to complete it in China as a 'learning' prototype for future production but could find no practical way to ship the bits.
The plane was originally funded by the USSR so it does raise the question of who actually owns it. I have a suspicion that Putin would feel it was definitely not the property of Ukraine based Antonov.

Still printing. The elegant exhaust nozzles that reduce the exhaust area to 85% of the PSA (prop swept area?) which actually increases the thrust slightly.

The front part of a nacelle being printed showing the "gyroid" infill pattern. This was not available in CURA when I did the AN124 nacelles.

For a slight increase in printing time, now 3 hrs 9 mins, it greatly increases the support to the skin resulting in a stiffer structure. The close support also allows a thinner wall thickness to be used so eliminating any weight increase from the extra quantity of infill.

What's the clearance between the prop & the duct wall Q ?

crash
The tip clearance is actually the bit I am most proud of. Its just a bit less than the thickness of a piece of printer paper!
I made this video to demonstrate.

The paper is a friction fit so stays in place.
This was the unit shown running in the previous video so it does have clearance.

The motor mount is separate to the prop 'shroud'.

Once the motor is screwed onto the mount the shroud is then glued on with UHU POR which allows very careful positioning to ensure equal prop tip clearance all round.

Of course if all else fails it is possible to 'machine down' the prop tips a bit by running the prop up against a sanding block.

That's a fine piece of engineering Q ! With that & the cones, you are definitely squeezing every bit of thrust out of those little motors ! Nice job.

Still more printing. I now have two complete nacelles with motors and props.

Some 15 hrs of printing with 3 different colour filaments.

I am doing all this simply because it is not really costing anything apart from my time and some printer filament.
The interest for me is to see how much I can improve the printing in terms of strength and weight even if the parts produced never actually get used. :woohoo:
The next job is to create the 10 big wing ribs required for the centre extension.

Organising the new wing ribs is proving to be rather tedious I suspect because I had forgotten how tedious it was the first time round. It is not a simple case of scaling, as I had hoped, each rib has to be structurally modified to give the appropriate strength and stiffness for its size. :woohoo:
So far this is the biggest, the centre line rib.

It is 22.5" (570 mm) long and 3.125" (80 mm) deep. The external measurements of the wing would of course be a touch bigger.

I am sure there are many planes with bigger dimensions than this but probably not made of 3D printed parts & Depron.

A lot more printing today.
The full set of wing ribs for the centre section insert.

13 ribs each made up of 3 bits, except the mid rib which has 4, so 40 parts in all and as they are printed in L & R hand sets they are all different. :woohoo:

That's about as far as I can go at the moment so I shall have to find something else, maybe 'renovate' the so far not very successful DH Albatross - every flight ended with control issues and damage.

Given that the AN124 actually flew quite well and did not destroy itself this thread came back into mind.:woohoo:
I have already printed most of the parts required and I think I have just enough enough Depron.
Before going any further I have to really check if the 'expanded' bits would fit into my car so this is a picture of the AN 225 using excatly the bits of the AN124 by the wonders of 'cut and paste'.

The killer bit is the 6 motor wing centre section. For structural reasons it has to be in one piece. I will have to make a full size card board template to see if it is possible to get it in the car.
The fuselage will be quite a bit longer but with a joint just ahead of the wing, so not load bearing, it will be of similar length to the existing so will fit.
The fuselage will actually use the existing AN124 nose and tail sections but each with extensions. The extended tail section will be added to the completely new under wing section.
Of course the sensible thing to do would be to fly the AN124 until it does crash and then simply give up the whole idea.

You're a glutton for punishment! [badass] :woohoo:

Time for a new car?