“What will happen if, once I have delivered all my products, we notice that there is a big bug? »

This is THE question that kills. I think every entrepreneur has to deal with it one day – presumably even Volkswagen.

Sir " bin plus zero was convinced that he could produce a faultless product, on his own, the first time. Fortunately, the reality of life was there to remind him that we are not in Care Bear country.

So it's done: I missed Pioupiou 🙂

Well, don't be too scared. In fact it's fine. Read all the way down...

My god, what's going on?

The problem is here:

Short version :

Under certain conditions, the propeller has difficulty turning. It becomes less sensitive and underestimates the wind speed.

Long version :

We have a kind of big chain reaction.

The first problem is that I misdesigned the bearing housing. They are placed directly in the plastic shell. However, its shape is not completely fixed (molding tolerances, temperature variations). As a result, the two bearings are not necessarily well aligned, and it rubs more than expected.

The second problem is that the bearings that were delivered to me are not completely the right size. As a result, they do not tighten enough on the axis. Under certain conditions, the shaft rotates − but the bearing does not.

First side effect: the bearing is made of very hard ceramic, while the axis is made of very malleable marine/food grade stainless steel. You can experiment at home: take mum's beautiful ceramic knife, and rub the tip on the bottom of her favorite IKEA pan (ps: it's not my fault). Suddenly, the bearings nibble the axis − which becomes even less tight − which slips even more − which accelerates the nibbling.

Second side effect: the nibbled stainless steel dust gets into the balls which prevents rotation...

In short, it's completely bogus.

Ironically

I wanted to do too well. It is the choice of these bearings " high-tech “, initially supposed to make the product more reliable, which ultimately caused all the problems.

This choice was not trivial, because these bearings cost 20 to 30x more than conventional stainless steel bearings. It was a non-negligible share in the manufacturing price of the Pioupious.

Moreover, the cost of these bearings is so high, that it was impossible to get supplies in Europe (at least, not for a Pioupiou at this price). Which forced me to go get them in China − with all the worries that go with it. The prototypes had been made with the bearings of a first supplier. Unfortunately, this one never delivered the bearings for the entire series to me (I got my money back). It was therefore necessary to change supplier at the last moment, and a priori the quality is not there.

Not even hurt

It cost me dearly in psychological endurance. It completely screwed up my schedule. But in the end, all's well that ends well.

So I spent some time to re-design the whole binding.

before:

after:

Exit the poorly mastered ceramic bearings made in china. I replace them with stainless steel bearings from a European supplier. I would therefore have standard bearings, with the correct dimensional tolerances and no surprises.

I also take this opportunity to redo an axle with a tighter fit.

And finally, I add a brass ring (in aluminum on the photo) which will keep the two bearings well aligned. They will therefore be better maintained than previously. The assembly can remain very stable, despite the deformations of the plastic shell.

So, I placed the order for the bearings, and I started manufacturing for the new axles and bushings.

In general, the delays on this kind of parts are a few weeks. But I was able to arrange so that the factory (Haute-Savoie) could make this for me in a hurry. We should have them by the end of the week, or the beginning of the following week.

After-sales service

Since all the Pioupious already in place risk being affected by the problem, we will replace everything.

I will therefore suggest that you either send you the parts to make the change yourself (instructions here), or to return the Pioupiou to me so that I can take care of it (obviously, for free).

It's extra work, but out of the question for me to leave these Pioupious in agony. We have launched a project, we will see it through to the end! Banzai!

Obviously, the problem is corrected for all Pioupiou delivered from now on.