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Fred Klein
Joined: 26 Mar 2012
Posts: 503
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 Posted: Mon May 21, 2012 6:18 pm Post subject: GA propellers |
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Once again, the value of the europa-list and being part of this on-line community was demonstrated to me.
Though I'm well aware of the advantages of CS props, I've opted for a Ground Adjustable prop, at least for initial flight tests, for a variety of reasons including cost, personal unfamiliarity w/ CS prop ops, complexity, and cockpit workload issues. Finding the right prop for Ms. Suburopa was not as easy as I'd anticipated...it was a challenge to find one which could spin counter-clockwise, absorb 140 hp, rev. higher than 2700 rpm, and be not larger than 66" diameter. Other than putting the cut-down Warp Drive blades in their GA hub, I found nothing...until...I came across www.gaprop.eu...a Ukrainian company which is affiliated w/ a Finnish company, Light Avia (light.avia(at)gmail.com (light.avia(at)gmail.com)).
While I was hesitant to deal w/ a company from so far away which had no representation in the US, when I saw that the company had the office in Finland, on a lark I emailed Raimo Tolvio...lo and behold, the office was only 15 km from Raimo's home! He kindly volunteered to check out the company, and thanks to him, my confidence became high enough ultimately to wire transfer funds. When the prop was delivered in Finland, Raimo again went to the Light Avia office, inspected each part...and even repacked the parcel to ensure it would arrive safely in the US.
I've just received 3 beautiful carbon-fiber blades (autoclaved w/ SS leading edge) w/ padded covers, a CNC-machined, anodized alum. hub, a 90 mm CNC-machined aluminum extension, and all required bolts. The prop is good for up to 150 hp and 2900 rpm. I consider the quality superb w/ the exception of the "CW 8.8" stamped bolts which I know nothing about...(my local auto parts store sez the "CW" stands for Chinese Warehouse...I'm not sure if he was serious). Price for the entire package, including 5 day shipping from Finland to the west coast USA was 815 euros.
Of course, GA Prop / Light Avia make most of their props for Rotax 9XX engines. As I'm not yet flying, I cannot offer any operational experience, but I would certainly recommend giving this company consideration if your're looking for a ground adjustable prop. Raimo mentioned that he'd heard of impromptu static testing by Finnish airmen which showed 20 to 30% increase in static thrust over the WD blades set at equivalent blade angles and running at the same rpm.
Cheers,
Fred
[quote][b]
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tennant
Joined: 19 Apr 2011
Posts: 121
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| Posted: Sun May 27, 2012 11:52 am Post subject: Re: GA propellers |
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Hi Fred,
FYI 8.8 bolt spec is min. 800 Newton per mm squared tensile and min 80% of that as Yield strength.
i.e. for non Europeans: min 116 ksi tensile
There are certainly stronger bolts on the market but this is pretty standard and they are not brittle and can be safely plated.
Barry
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Barry Tennant
D-EHBT
At EDLM - Germany |
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Fred Klein
Joined: 26 Mar 2012
Posts: 503
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| Posted: Mon May 28, 2012 7:31 am Post subject: GA propellers |
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On May 27, 2012, at 12:52 PM, tennant wrote:
| Quote: |
>
FYI 8.8 bolt spec is min. 800 Newton per mm squared tensile and min
80% of that as Yield strength.
i.e. for non Europeans: min 116 ksi tensile
There are certainly stronger bolts on the market but this is pretty
standard and they are not brittle and can be safely plated.
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Barry,
Thank you for your explanation...the torquing values called for for
the 8 mm bolts is listed as 2.5 kg*m / 25 N*m. This reads like Greek
to me, but if I am reading this correctly, it would appear that the
loads are well within the bolt spec and I should have no hesitation to
use the bolts which came w/ my superb (by all appearances) propeller.
Your confirmation would be appreciated.
Fred
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tennant
Joined: 19 Apr 2011
Posts: 121
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| Posted: Tue May 29, 2012 6:26 am Post subject: Re: GA propellers |
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Hi Fred,
Thats 18.1 Ft/Lbs
No problem. Do not lubricate the threads as this can falsify the stress put on the bolt.
Best regards
Barry
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Barry Tennant
D-EHBT
At EDLM - Germany |
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