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vgstol(at)bigpond.net.au
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 Posted: Mon Jan 11, 2010 3:52 pm Post subject: Fork tube analysis and prospective stainless steel substit |
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I once helped re-build a 701 that had hit a fence on take-off. A heavier nose leg had been fitted, causing the firewall to be damaged as well. Replacing the firewall is a MAJOR job........ A new nose leg and prop are much easier and less costly......
Don't know how you can bend a nose leg on a 701, even in a heavy landing scenario. The nose wheel should be way high off the ground at landing AofA, and the weight distribution should be such that you can hold the nose up after the mains take the weight. The vertical CofG of the aircraft is quite high, such that at the AofA at touchdown it effectively moves back and the aircraft nearly balances on the mains at that attitude. If you can't hold the nose up and it comes down hard, then either the horizontal CofG is way forward, or the main gear is canted back somewhat. The 'angle of dangle' of the main gear is often not noticed, but can vary due to wear or improper fitting of those rubber blocks. If the gear is angled back just a bit it puts much more load on the nose wheel. For real STOL use, especially on rough strips, it's best to try to have the weight on the nose wheel to be minimum. Fully loaded to aft CofG, if someone pulls the tail down to the ground, it should just about stay there. The angle of the main gear can be adjusted, often by just reversing those rubber blocks, or if necessary by grinding a slight taper on them with a course sanding disc in an angle grinder. But of course, first must get the CofG of the aircraft correct, by weight and balance measurements.
JG
www.stolspeed.com
On Tue, Jan 12, 2010 at 7:18 AM, Curt Thompson <Curt.Thompson(at)verizon.net (Curt.Thompson(at)verizon.net)> wrote:
[quote]
Here is a link to the previous thread that has pictures of how the fork tube bent.
http://forums.matronics.com/viewtopic.php?t=56639&highlight=weak+701+nose+gear
Curt
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ist" target="_blank">http://www.matronics.com/Navigator?Zenith701801-List
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vgstol(at)bigpond.net.au
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| Posted: Tue Jan 12, 2010 4:52 pm Post subject: Fork tube analysis and prospective stainless steel substit |
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Yep, land it like a taildragger and use the nosewheel only for taxiing. The nosewheel is plenty strong.
Well said!
JG
On Wed, Jan 13, 2010 at 9:54 AM, BokKat <bobkat(at)btinet.net (bobkat(at)btinet.net)> wrote:
[quote] Yep, land it like a taildragger and use the nosewheel only for taxiing. The nosewheel is plenty strong.
[b]
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lgold(at)quantum-associat
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| Posted: Mon Jan 18, 2010 9:29 pm Post subject: Fork tube analysis and prospective stainless steel substit |
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JG,
There were two scenarios re this failure after ruling out construction error (which I say no sign off). First, some small metal debris was discovered on the runway that may have impacted and contributes. Second, the student pilot was on his check ride with a flight examiner and was making a short field landing. Some speculated that she may have applied brakes before touching down, which would have made the nose wheel impact hard. The student pilot said this was not the case, but we know how nervous we can be in a test situation.
Les
From: owner-zenith701801-list-server(at)matronics.com [mailto:owner-zenith701801-list-server(at)matronics.com] On Behalf Of JG
Sent: Monday, January 11, 2010 3:52 PM
To: zenith701801-list(at)matronics.com
Subject: Re: Fork tube analysis and prospective stainless steel substitute
I once helped re-build a 701 that had hit a fence on take-off. A heavier nose leg had been fitted, causing the firewall to be damaged as well. Replacing the firewall is a MAJOR job........ A new nose leg and prop are much easier and less costly......
Don't know how you can bend a nose leg on a 701, even in a heavy landing scenario. The nose wheel should be way high off the ground at landing AofA, and the weight distribution should be such that you can hold the nose up after the mains take the weight. The vertical CofG of the aircraft is quite high, such that at the AofA at touchdown it effectively moves back and the aircraft nearly balances on the mains at that attitude. If you can't hold the nose up and it comes down hard, then either the horizontal CofG is way forward, or the main gear is canted back somewhat. The 'angle of dangle' of the main gear is often not noticed, but can vary due to wear or improper fitting of those rubber blocks. If the gear is angled back just a bit it puts much more load on the nose wheel. For real STOL use, especially on rough strips, it's best to try to have the weight on the nose wheel to be minimum. Fully loaded to aft CofG, if someone pulls the tail down to the ground, it should just about stay there. The angle of the main gear can be adjusted, often by just reversing those rubber blocks, or if necessary by grinding a slight taper on them with a course sanding disc in an angle grinder. But of course, first must get the CofG of the aircraft correct, by weight and balance measurements.
JG
www.stolspeed.com
On Tue, Jan 12, 2010 at 7:18 AM, Curt Thompson <Curt.Thompson(at)verizon.net (Curt.Thompson(at)verizon.net)> wrote:
Here is a link to the previous thread that has pictures of how the fork tube bent.
http://forums.matronics.com/viewtopic.php?t=56639&highlight=weak+701+nose+gear
Curt
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