Hubcaps - why?

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michael.g.miller
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Hubcaps - why?

Post by michael.g.miller »

My DA42 has hubcaps on both main wheels. This makes it a bit of a chore to add air. Do the hubcaps serve any useful purpose? Or are they primarily cosmetic?
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chili4way
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Re: Hubcaps - why?

Post by chili4way »

Photo?
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michael.g.miller
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Re: Hubcaps - why?

Post by michael.g.miller »

The valve stem is on the side of the tire facing the camera, but under the circular metal plate (hubcap). To add air you need to unscrew the hubcap, add air, and screw it back in.
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Steve
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Re: Hubcaps - why?

Post by Steve »

Smooth airflow over the exposed, retracted wheel? The difference might be so small as to be unmeasurable, and theoretical only at DA-42 speeds.
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Boatguy
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Re: Hubcaps - why?

Post by Boatguy »

Can't imagine why since it's a retractable gear. You lower the gear either because you want the drag to slow down, or you have an imminent landing.

This is a factory delivered thing?
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ememic99
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Re: Hubcaps - why?

Post by ememic99 »

I guess to protect the valve while taxing on grass field.
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Re: Hubcaps - why?

Post by CFIDave »

I've seen magazine ads for "hub caps" over the retractable main gear wheels of Cessna twins (300 and 400 series) that claim drag reduction sufficient to add multiple knots of airspeed. This may apply to DA42/DA62 retractable gear wheel covers.
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Re: Hubcaps - why?

Post by Karl »

michael.g.miller wrote: Wed Sep 22, 2021 5:48 pm My DA42 has hubcaps on both main wheels. This makes it a bit of a chore to add air. Do the hubcaps serve any useful purpose? Or are they primarily cosmetic?
They reduce drag.

Not sure why it is a chore you shouldn't need to add air very often. If it's more than about once every six months then you probably have a leaking valve.
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Re: Hubcaps - why?

Post by janders »

Boatguy wrote: Thu Sep 23, 2021 5:00 am Can't imagine why since it's a retractable gear. You lower the gear either because you want the drag to slow down, or you have an imminent landing.

This is a factory delivered thing?
The distal sides of the wheel and the hub are exposed to the airstream when the gear is up. The cover over the hub reduces drag.

And I agree, on the DA62 too, it's a pain to get that little screw out that's behind the wheel door and to then rotate the cover away. I keep a short stubby screwdriver in the nose compartment for this purpose.
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Re: Hubcaps - why?

Post by ememic99 »

BA33E127-2F01-4E14-B514-FDC0209168F1.jpeg
Who would say that so much drag world be generated without hubcaps….
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