SPA Modeler

Now let’s just hope that the shipping company is not so brutal this time around.

I thought I'd share a bit of the packing process for Black 1. My packing is based almost verbatim on an excellent article by Brian Leitch over at LSP. You can reference the article directly here:

https://www.largescaleplanes.com/articl ... hp?aid=482

The main strategy of Brian's packing method is to create a truss or frame using foam core board. This frame fits the inside of the inner box exactly, keeping the model immobile. The inner box is placed into an outer box, suspended in packing peanuts, forming another layer of protection.

Based on the dimensions of my model, my inner box is 14" wide by 14" long by 8" high.


The foam board frame will be a "tic-tac-toe" configuration using four sheets. Since my box is a square, the dimensions of each piece is 14" x 8".


You can see how the pieces fit exactly inside the box.


To figure out how the four pieces fit together, I need to determine the contact points between the frame and model. I label the inner corners of the box and the orientation of the model within the box for reference. Two of the frames will be oriented longitudinally to the model (front to back) and each of the frame pieces are labelled with the corner labels.


The other two frames are oriented laterally (left to right) and are also labelled.


I now place the model centered in the box.


I want the lateral frames to contact the model at sturdy points, one in the front and one at the rear, avoiding any delicate parts such as antennae, gun barrels, landing gear, flaps, etc. The area under the nose between the radiator cowling and the end of the wing gun barrels is a good spot on the front. Based on the breaking of Black 1 at the tail joint, I want the rear lateral frame to contact the fuselage of the model OUTSIDE of the tail joint. The previous frame, which resulted in the tail breaking loose, left the tail joint (and the whole tail unit) hanging outside of the frame. These points are marked on the frame piece.


I do the same thing for the longitudinal frames, wanting them to contact the wings just outboard of the lowered flaps.


These intersecting points are marked on the frame pieces as vertical lines. I want the four frame pieces to interlock so the vertical lines indicate where vertical grooves will be.



The grooves are the width of the foam board and run to the midpoint of each frame piece. The grooves are cut from above on the longitudinal pieces and from below on the lateral pieces so that the four frame pieces can be interlocked.


After the groove are cut, I can assemble the frame.


The frame should fit exactly within the interior of the inner box.


I can now verify the contact points between the model and the frame.

Interesting... how sturdy is the box and the bracing to resist crushing?

Thanks Bruce! In some ways, the packaging is more involved and worrisome than the build itself!

Sorry if I didn't quite explain the tail joint thing clearly. As you can see in the image below, I've designed the frame so that the joint is on the inner side of the frame. Previously, the joint was the outside of the frame, which left the entire tail + joint unsupported. It's just a guess but I thought that enough jostling occurred during shipment to cause the tail to work itself loose. So I took steps to make sure this did not happen including using JB Weld for the join and this modification in the foam frame configuration.


Here is a pic of the original frame. You can see how the tail section was just hanging outside of the frame, unsupported. I think establishing a strong glue joint would've prevented the breakage in the first place but adjusting the frame should help.

Stikpusher wrote:Interesting... how sturdy is the box and the bracing to resist crushing?

I dunno... you're guess is as good as mine. It's a cardboard box that I bought from the UPS store and did not come with a specifications sheet. It's classified as a 200# box, whatever that means. Crushing of the box is not one of my worries. The double box configuration should keep the inner box intact. I still have the inner box from the original shipment of Black 1 (two trips over the Atlantic) and it is still in good shape. I'm more worried about sharp impacts to the box (which may not even leave a mark) and I have no direct control over that.

This is like the school project for dropping the egg off the gym roof... designing an item to allow the egg to survive...

Stikpusher wrote:This is like the school project for dropping the egg off the gym roof... designing an item to allow the egg to survive...

I used balloons for that one, although credit should go to my father’s engineering background and competitiveness more than my own ingenuity.

John,

Thank you so much for your details on the design and support of the tail. I deeply feel what you meant about designing the support system as being a great challenge. What I always am grateful for is the way you show and describe the process. I have learned so much.

I did want to ask how you plan to ship the plane. I know there are companies dedicated to shipping art around the world and wonder if a carrier such as those might be helpful. Regardless, I am hopeful for a successful “mission” for the Dora!

Cut-outs in the frame allow the model to sit approximately in the middle of the frame. The important thing is to have the entire model suspended by the four predetermined contact points.


The model is placed in the frame cut-outs to confirm the position of the model within the frame.


Foam padding is then added to all of the contact points.


The model is locked into place using foam board pieces mounted above the contact points. For this model there are only three lock-down points: the nose and the two wings since the aerial prevents securing the tail. These pieces are secured into place using short pieces of 1/4" dowel and friction-fit wood "filials" that I found at an online craft store.


The model is placed in the frame upon the new padding.


The three lock-down pieces are put into place. Before drilling the holes for the wood dowel/filials, test-fitting of the lock-down pieces ensures that model is rendered immobile within the frame. THIS IS VERY IMPORTANT! The frame that I used to ship Black 1 did not secure the model completely. There was some "give" and I erroneously thought that it was ok.


With the model secured with the lock-down pieces, the foam frame is now an independent structure capable of holding and protecting the model to a certain extent by itself. I can flip the model over on its side.


And I can turn the model over upside down. Note: the landing gear legs worked themselves loose during original shipment. Keeping in mind that they were metal legs and relatively heavy, I think I will secure them with a bit of tape to reduce the stress on the small attachment point.


Just to show how the frame holds the model securely.


The frame gains significant rigidity and strength once it is placed in the box.


The frame and the inner box are finished. I will close the inner box with tape and then place it into an outerbox, suspended with packing material.

Your packing work looks a-mazing, John! Truly spectacular job! Congratulations!