Building from a kit - I need some feedback

[old man emu]

I've been engaged by a company to organise the way individual components (nuts, bolts, fittings and other elements) are packaged together for a kit built plane. I'm lucky in that I can create a system that ultimately is user friendly for the kit builder, and then I can work backwards to develop a way that all the bits are identified in the manufacturer's inventory.

 

So, the feedback I need is from people who have, or who are, building from a kit. I'd like to know if the best way to do this is to package everything needed to install a sub-assembly (like an aileron control system) in one bag/box, or to package all the same sized bolts, nuts etc to be used in the whole build and let the builder pick out the correct bits for each sub-assembly as needed.

 

My idea is that if I put everything needed for a sub-assembly in one package, with a Bill of Materials linked to the parts description on the plan, then the job would be easier for the builder.

 

Don't worry about traceability matters as that would already have been taken care of though the inventory system.

 

Please let me know of any problems, or solutions you may have encountered in your build by sending me a PM. If I need further information arising from the PM, I'll give the sender my email address.

 

Thanks

 

Old Man Emu

 

 

[rankamateur]

ICP do most of the bolts for Savannah kits just like you describe now, they haven't always been like that but got a lot easier to deal with once they were. There is still a portion of the hardware supplied in a random lucky dip bag, mostly around the engine installation, it is a bit of a nightmare for a first time builder. The bill of materials linked to the parts list would be a big improvement on what they do now. There is a parts list at the beginning of each build chapter but it is notoriously incomplete particularly where kit improvements are concerned.

 

 

[rgmwa]

My idea is that if I put everything needed for a sub-assembly in one package, with a Bill of Materials linked to the parts description on the plan, then the job would be easier for the builder.

That's how Vans do it. Makes it easy to check that all the required parts are there. The builder can then put all the common small items like nuts, bolts, rivets etc together in something like this:

 

 

 

[IBob]

If possible, I would package the parts by sub-assembly. The benefits that I can see (in no particular order).

 

1. Easier for the builder to check he has received all parts.

 

2. Easier for the builder to pull the parts, allowing him/her to proceed with confidence. And for the amateur first-time builder, confidence is important.

 

2. Less chance of the builder pulling an incorrect part in error.

 

3. Easier for the manufacturer to correctly adjust parts and quantities as the aircraft design evolves or changes. This may seem like a small issue, but if the parts are 'all in together' and a quantity is incorrect, the manufacturer does not know where it is incorrect. And the builder does not know if he has too many/too few because he has used an incorrect part elsewhere.

 

 

[old man emu]

Trike1,

 

Please expand on the reasons for advising caution here.

 

OME

 

 

[Steve L]

OME maybe Trike1 may have hit the wrong button.

 

No lucky dip from KFA ( Bushbaby Explorer ) which I'm building, all parts were in clearly marked with part numbers in plastic bags which I stapled to a peg board on the wall of the hanger. Made it easier to check off with the packing list and heaps easier to see when assembling the kit. even the bungee cords were in a clearly marked plastic bag ( I guess some might think they were for holding luggage down haha ) anyway I have just got home and I,ll

 

take a pic tomoro and post it.

 

steve

 

 

[KRviator]

Trike1,Please expand on the reasons for advising caution here.

OME

Don't read too much into it. Probably done what I've done a dozen times viewing the site on the iPad when scrolling down and not even realised it. Now, as for the OP: It depends what you want to achieve. I understand Jabiru package every part needed for the particular task on a piece of shrink-wrapped cardboard and label that with the assembly/task. This would greatly speed production provided everything goes well, but if you strip a bolt or booger up a part, you now need to raid your other sub-assemblies to find something to replace your boogered-up part.

 

Vans do it the opposite. They package things in bags, but, most builders (including me) separate them into individual hardware types. For me, all rivets went into a couple of tackle boxes, in individual compartments ordered by size, ie 426AD3-3, 426AD3-4, etc. Same with bolts. This means you can learn parts, bolt sizes and rivets, etc, based on appearances, and also readily go to your stash to replace a dropped rivet. The disadvantage to this method is you need to sort & store each nut & bolt at the beginning of your build, and if you have never built a plane before, the difference between two virtually-identical rod end bearings that came in the same bag is hard to see.

 

That being said - I would strongly encourage the Vans method. Identical parts in individual bags, it works well, it teaches the user about what is what (important if you're building your own plane) and it felt reasonably fast when I knew I needed a rivet and could go straight to the rivet/bolt/nut/washer box and grab exactly what I needed.

 

 

[old man emu]

Seems Trike's fingers should more walking and thin down some.

 

I thought he might have been playing the liability card, and I wanted to hear his story.

 

We can see that there are two schools of thought here. I'll take both into consideration. However, having done the storeman's role in a maintenance facility, I well know that inexperienced AMEs rarely know the the part numbers of the things they want. Same would apply to a home-builder.

 

Your comment about dropped rivets causes me to consider adding a small percentage for wastage. I suppose the ability to provide replacement of builder buggered bits will be a measure of after sales service.

 

OME

 

 

[SDQDI]

I think it makes more sense to have all identical bits kept together rather than separating them into sub assemblies. There is nothing worse than having half a dozen packets of the same bolt or nut, it just adds clutter.

 

Actually for what it is worth it would be nice to have all small bits come from the manufacturer in a hard case similar to rgmwa's all labelled in a way that won't fade after a couple of weeks. I know it may add a bit to production costs but the end product would be so much more user friendly for only a small increase, much better than individual bags or shrink wrapped parts which need half sorting to start with.

 

As for spares it is always nice to have some as it doesn't take much effort or innattention to lose or ruin small parts but where do you stop? I would think a spare bolt or two for each particular size would be ok and if using nylocs then maybe a few extra spares of those and then rivets I think you would be negligent if you had less than 100 spares. (Who has ever built a plane without drilling out a rivet or two?!)

 

 

[Downunder]

Your comment about dropped rivets causes me to consider adding a small percentage for wastage. I suppose the ability to provide replacement of builder buggered bits will be a measure of after sales service.OME

What about a few extras (rivets & sheet) for the builder to trial fitting them together. Damaging some scrap getting the technique right is far better than the real thing...... (have to remember builders may not have extensive metal working experience)

 

I'm all for individual sub-assemblies.

 

The problem with pulling bolts from a bulk container is that if you fit the wrong bolt, further down the track you are going to find yourself short in size, length or diameter.

 

Then you have to workout WHERE the errant bolt was fitted, do you need to remove/replace it, and what are you going to do about the one you need now.....

 

 

[bushcaddy105]

Depends on the type of kit - A kit with every last component supplied (RV12?) could benefit from sub-assembly packaging, but with a few extra applicable rivets in each pack. A materials kit would be better off with bulk packaging of each different fastener type. This makes it easier for individual variations on design, eg panel, alternative engines, nav light options, etc.

 

Other issue - Has there ever been a kit with perfect instructions and/or every drawing correctly notated?

 

 

[turboplanner]

Seems Trike's fingers should more walking and thin down some. I thought he might have been playing the liability card, and I wanted to hear his story.

We can see that there are two schools of thought here. I'll take both into consideration. However, having done the storeman's role in a maintenance facility, I well know that inexperienced AMEs rarely know the the part numbers of the things they want. Same would apply to a home-builder.

 

Your comment about dropped rivets causes me to consider adding a small percentage for wastage. I suppose the ability to provide replacement of builder buggered bits will be a measure of after sales service.

 

OME

Small number of replacements is a great idea, covers situations where item is damaged during assembly, lost, or the kit is 1 item short even though it was checked before dispatch. The hunt for a replacement from local component suppliers can take hours or require a delay of several hours/weeks, and the part you lose always seems to be the o e which will not allow you to fit the assembly and get on to the next stage.

 

 

[KRviator]

Other issue - Has there ever been a kit with perfect instructions and/or every drawing correctly notated?

I'm lead to believe the RV-12, & the -14 in particular, are about as close to perfect in that respect as you're likely to get.My -9 was very, very good too in that way but there were still a couple of questions I needed help on from The Mothership. But I love Lego Technic, so maybe that helped?

 

Another thought for a prospective kit supplier: make a set of 'preview plans' available to potential builders so they can see what they'll be working from. They don't have to be current, but if you can't read the drawings, you won't finish your plane!

 

 

[Jaba-who]

I personally would go for sub-assemblies all together.

 

When I build the Jabiru they had a sort of half and half mixed up system.

 

The majority of specific bits for specific assemblies were on shrink wrapped cards but the majority of the hardware was in tray boxes with bolts nuts etc of same sizes in the compartments.

 

But they also had some hardware on the cards.

 

I found it difficult because some of the time I knew I had the right hardware because it came on the cards and then some of the time I was left floundering because I wasn't sure I had right hardware etc.

 

To give jabiru their due though - the bolts needed often varied from the size specified because the fibreglass layups are, by their nature, imprecise and often I needed to go up or down a length.

 

If your kit is more precise - say a metal kit - I'd be more inclined to suggest each complete sub-assembly should be on its own card in entirety.

 

 

[old man emu]

Small number of replacements is a great idea, covers situations where the kit is 1 item short even though it was checked before dispatch.

Not with my stringent packaging system, Sir.

 

The hunt for a replacement from local component suppliers can take hours or require a delay of several hours/weeks, .

Hopefully we will have sufficient pre-packaged stuff always on hand so that getting replacements is only an electronic communication away, and the replacement will have the same high level of traceability that the first delivered items did.

 

The majority of specific bits for specific assemblies were on shrink wrapped cards but the majority of the hardware was in tray boxes with bolts nuts etc of same sizes in the compartments.

This type of packaging is a bit advanced for a start-up. Also it adds cost to the whole kit, which I think the buyer would appreciate being eliminated. If I was a kit buyer I would like things to come packed "Task Specific". I would buy plastic take-away food containers and put what packages I could in them. ID the container with a Texta and store until required.

 

Once again, thanks heaps for the feedback. Keep it coming.

 

OME

 

 

[kgwilson]

All the bolts, nuts, washers, machine screws, nut plates special rivets & other fittings etc were in heat sealed plastic bags for sub assemblies & labeled in my kit. This was then able to be cross referenced with the parts list also by sub assembly. This was good as I found a few bits missing. I also had extras in some of the bags. Having a local supplier was good as a phone call or email resulted in the missing bits arriving within a few days. When it came to standard rivets they were supplied in bulk boxes so there were tons of spares.

 

 

[Steve L]

This is how I set the parts up as they came from the factory in sealed bags, everything is referenced in seconds no need for individual containers just staple them to a board. Most are in sub assemblies and

 

all part numbers are on the individual packets. Works well for me.

 

 

[fly_tornado]

I reckon you are better off quoting the weight of the smaller items so that your customers aren't forced to physically count the components

 

 

[rankamateur]

I reckon you are better off quoting the weight of the smaller items so that your customers aren't forced to physically count the components

I counted five hundred of each size rivets in my savannah kit and weighed the balance. It was the only way to finally prove ICP were being tight with the rivets. turns out there were plenty of rivets for a standard build but the extra fuel tanks, baggage compartment extension, rudder extension and so on were putting strain on the supply, so every builder was coming up short. Depending on how many factory options added the problem just got worse. The distributor supplied the extras needed and all was good.

 

 

[old man emu]

My packaging procedure will be to weigh 1000 rivets, then use this formula:

 

{(number of rivets required/1000) + (number of rivets required) x 0.01}.

 

In other words, 10% oversupply.

 

OME

 

 

[IBob]

My packaging procedure will be to weigh 1000 rivets, then use this formula:{(number of rivets required/1000) + (number of rivets required) x 0.01}.

 

In other words, 10% oversupply.

 

OME

Suggestion: for the bulk rivets (A4,1/8",3mm?) that should be plenty.

 

But for the low-quantity sizes, you may want to be a little more generous, if costs allow.

 

 

[IBob]

My packaging procedure will be to weigh 1000 rivets, then use this formula:{(number of rivets required/1000) + (number of rivets required) x 0.01}.

 

In other words, 10% oversupply.

 

OME

Further suggestion, on the subject of rivets:

 

The novice builder receives various bags of various size and type rivets. Where these go are a mystery to him until (and unless) he finds them identified in the manual/instructions.

 

How hard would it be to provide a general summary in the manual?

 

Something like:

 

The tail fin uses A4 dome headed aluminium and A3 countersink aluminium.

 

etc.

 

 

[old man emu]

At this stage, the plan is for each sub-assembly to have a package which contains everything needed for the sub-assembly. For example, although the fuselage skins will have the same number of rivets on both sides, there will be a packages marked "Fuselage skin - left side" and another "Fuselage skin - right side".

 

Note that we are not using 'port' & 'starbord', but 'left' & 'right', for simplicity's sake.

 

 

[Geoff_H]

The very best numbering system for very large scale projects for both design and construction is the KKS (German initials for K? K? System). It is freely available to use and allows both designer and manufacturer to instantly know most of the number of the part. It uses alpha numerical letters to avoid confusion. If you areinterested I am prepared to show it toyou but not by dozens of emails, it would have to be by meeting, I will go to yourself, I have to go your way soon.

 

 

[Geoff_H]

PS I have used it on several occasions. I swear by it.