Bud
Thanks - I've copied your reply back to the list as it originally just
went to my pm.
RCC
On 17/01/2012, Bud Yerly <budyerly@msn.com> wrote:
> Richard,
> Sorry for the long delay on answering your Mono clearance question. We have
> three aircraft in final and one nearing final and my painter Johnny
> Hardacher decides to have a heart attack. I have been monitoring Johnny
> closely and he has been in bad shape for three months. He is rounding the
> corner now and is back at work a few hours a day. We sure miss him. His
> guys are now picking up the slack and we have full confidence we will finish
> all the aircraft at the end of this month. It will be nice to have the shop
> cleared out and get back to a 5 day week again as we have Sun 'n Fun coming
> up.
>
> As for the Mono clearances (I am not a mono flier and have only repaired and
> assisted owners using the 7 inch tire) I do not have company ground
> clearance records. I have found from observation only that in a three point
> attitude a flat tire leaves just over 9 inches with the 64 inch prop. The
> FAA/International requirement is 9. Now in a level attitude such as a
> complete tire failure on roll out tail high at high speed (which I am too
> much of a coward to do in the mono) and the tire were to fail to the rim,
> the clearance is only two inches on the rim.
> This I determined on Jim Brown's aircraft with a flat tire on the
> transporter when trying to get it off the mono trailer. Ed, my A&P watched
> the actual clearance from the nose and Chris and I sat on the wings prior to
> getting the tail off the transporter to get stuff out of the cockpit. A
> quick caution from Ed alerted us to do some math. We had 3 inches of tire
> from the rim to the ground at zero psi and the prop clearance was at 5
> inches. Math in public stating that 5-3 is two inches of prop clearance
> from the rim with the tail up. On bumpy grass, with a shredded tire, I
> think you may be mowing the grass a bit. So keep the stick back.
>
> John Bolyard's mono motorglider at 1350 lbs. (Brand new block and 7 inch
> tire, full power with 914 for engine run up tests, prop clearance was 13
> inches in three point at full power and at tail up , or level, he still had
> about 9 inches clearance with his block. My concern is the rubber block. I
> just don't have data for an old block nor do I have a limit other than what
> you mono guys tell me. My feeling is, change the block at 5 years, but
> again, I really don't have sound data on how long the block should go before
> it begins to fade. Those old red blocks are finally out of the system and
> the black ones hold up pretty well so your initial measurements when you
> build the aircraft are the best measure of when to change the block. If it
> sinks a bit over time then change the block.
>
> If any mono pros out there have data, please speak up as I am out of my
> comfort zone and have no physical test data from production, just the
> install manual stuff and observations above....
>
> Regards,
> Bud
>
>
> ----- Original Message -----
> From: Richard Churchill-Coleman<mailto:richard.churchill-coleman@sky.com>
> To: 'Bud Yerly'<mailto:budyerly@msn.com>
> Sent: Thursday, December 29, 2011 7:01 AM
> Subject: FW: Europa-List:
>
>
> Hey Bud
>
> Fantastic information! Do you happen to know the clearance for an XS mono
> when fully loaded and set level for take off? I have a 1640mm diameter prop
> (64.5") and my high school trigonometry says I will have enough ground
> clearance to be legal under UK rules (needs 230mm - 9" - with tyre inflated
> and positive clearance with tyre deflated: so the same as FAA rules) but I'd
> love to know the real world answer rather than rely on my math?
>
> Kind regards
> Richard C-C
>
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