Official FlightLine 1600mm P-51D Mustang Thread

[Grossman56]

Hi guys, let me chime in here.
I went over the tank and reduced the wall thickness in the center section from 3.5mm to 2.0mm then reduced the reinforcing in the nose and tail by half.
The one thing that either of us didn't consider was the CG of the tank itself, which could cause some of the problem when you get into such relatively large pieces.
Anyway, the V3A Light will look and fit together exactly the same, so we'll see what the weight comes out as.
I'll say one thing, they look freaking AWESOME! if I do say so myself, I've only seen the design but to physically see my creation is just such a thrill!

Grossman56
(Dangerous Dan)

[Grossman56]

Now I have to somehow get my hands on one of these planes so I can hang a set on my own!!

[davegee]

Now I have to somehow get my hands on one of these planes so I can hang a set on my own!!

Hi Dan: I have been looking into another idea on the tanks. My CG for the V3A tanks is too far aft. I'm thinking with your new lightened tank parts, if I move the slot on the tank back about .75"-1" it will align closer to the airplane's actual CG which has a manufacturer's mark on the bottom of the wing. This would also take a lot of the strain off the downward movement of the aft part of the tank that I experienced today. This would allow the single connector on the pylon maybe to hold the tank in place, instead of it falling off during taxi trials. That's what I'm thinking, anyway.

When you get the new lightened parts finished, send them to my gmail and I'll print them up, make the slot for the tank to pylon aft about .75 inches or so, and see if we can get the tank CG and the airplane's CG to get pretty close together. That might be the secret to getting these large drop tanks to work like we want them to!

Cheers

Davegee

[davegee]

"On the Shoulders of Giants"...

Been working hard on coming up with a droppable, scale 110 gallon tank that can be released in the air and come down (hopefully) undamaged. There have been several test iterations of this concept recently, starting with tanks that were carried and dropped successfully, but were too large for scale. That has been corrected, and Dan and I working together, him on the computer designing these parts, and me printing, testing, and putting them together for eventual flying. We're not there quite yet, but I hope to do a test fly and drop later this week with P-51D HHH.Finally got the CG of the long and fairly heavy tanks to line up with the CG of the wing. That was no small accomplishment. We'll see when we do taxi and hopefully flight tests how they do. We take heed from lessons learned with each disappointment or failure. That helps develop better results later.

Below is a picture of the various iterations in test that we have been working on. In the back are parts of the original "too large" tanks, and in the foreground is the current test article along with a twin being fabricated now will try the taxi/flight test drops later this week. The reason for the mulitlple colors of the tank, is that I ran out of my preferred silver filament, and had to do with what I had lying around until a replacenent spool comes today. (they'll all get a grey primer and silver coat, anyway!) But we got the weight down substantially by a couple of ounces or more by thinning the walls as much as possible and I"m hopeful they'll be successful this week.

Assuming that goes well, continued testing in the shop and in flight, and then painting and detailing for the final product.

Back to the workshop!

Cheers

Davegee

[nuts-n-volts]

Dave, I really don't know much about 3dp (I don't own one), but I was wondering... Would the material used for tires work? If the tanks were rubbery, they may take a hit better than if they are stiff.

[Elbee]

The material TPU is what you're thinking of and depending on whether you use the foaming variant or the pre-foamed variant your results vary by the temperature parts are printed.those would also be super lightweight. The surface quality can be porous looking, so any post processing adds weight. I would try it in a heartbeat.

[davegee]

Dave, I really don't know much about 3dp (I don't own one), but I was wondering... Would the material used for tires work? If the tanks were rubbery, they may take a hit better than if they are stiff.

It's a moving and developing target. Might be a possibility to look into.

Thanks,

Davegee

[davegee]

Thanks, Elbee. I'm not familiar with TPU. I did try Color Fabb LW-PLA on a different project about a year ago, but I didn't have much luck with reducing weight. In fact, it was the same weight as regular PLA. Probably operator error.

I'll check into it (TPU). As soon as the wind dies down, whenever that occurs this week, I plan on flying HHH and see how these latest test flights go. Do you know of a good vendor for picking up a spool of it to try?

Thanks,

Davegee

[Elbee]

I sent you a tali wheel for one of your projects. That was printed with TPU, but not the foaming variant. However, that can be printed at a higher temp to change its' viscocities. LWPLA would be a decent choice, though you need to print at a heigher temp to get the benefits of the foaming action. The distinction is some products are pre-foamed and some you choose the amount of foaming by print temperature. Id you didn't have much luck with the LWPLA change the design. You can print thin walls with differing infill patterns and achieve strenghth and light weight. It is definately a learn as you go process. There's going to be a compromise between scale fidelity and something you can drop more than once or twice without breking the part.