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[173.172.120.114]) by mx.google.com with ESMTPSA id n5sm9307617oer.5.2014.01.24.09.36.10 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 24 Jan 2014 09:36:10 -0800 (PST) Subject: Re: [FlyRotary] Velocity tire blow out References: From: Mark Steitle Content-Type: multipart/alternative; boundary=Apple-Mail-646B1F0B-3D09-41E0-B1AA-F9991E1E6A34 X-Mailer: iPad Mail (11B554a) In-Reply-To: Message-Id: Date: Fri, 24 Jan 2014 11:36:10 -0600 To: Rotary motors in aircraft Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) --Apple-Mail-646B1F0B-3D09-41E0-B1AA-F9991E1E6A34 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Chris,=20 My 2 cents worth... This sounds more line a toe-in /toe-out situation. Whi= le it may be perfect while in a static state, it could go to a toe-out condi= tion due to gear flex under hard braking. Camber doesn't typically cause ra= pid tire wear, but toe-in / toe-out will. =20 Mark Sent from my iPad > On Jan 24, 2014, at 12:37 AM, Chris Barber wro= te: >=20 > Well, on one hand I am pleased that when I did a quick loop of the pattern= after I got off work this morning (I just switched to graveyard shift this w= eek so get off work at 0700 hrs) my rotary ran smooth and strong and seemed t= o be producing pretty kick ass power. >=20 > HOWEVER, when I landed, I had my starboard tire blow out. Yes, it is quite= the attention getter. I swayed slightly to the right of center of the runwa= y at LVJ and luckily exited the taxiway closest to my hangar. >=20 > I was able to get it back to the hangar. No damage to the aircraft this ti= me, not even the tire rim. But, I noted I had excessive wear on the inside o= f the tire.....much more than i would have expected with only 15 landings an= d less than seven hours of flight. I have done extensive taxi testing though= (basically having and expensive go-cart) >=20 > I had noted on my conditional inspection that I had uneven wear but it did= not seem that bad and I pledged to mind it. I concluded that the uneven wea= r on the inner tire was due to the gear spread that I had noticed on my and o= ther canards (my hangar mate has a long easy and he is always lifting his bi= rd to get the gear from spreading after taxi). >=20 > Velocity is pretty specific on how to set the camber and recommend you set= the camber after installing the engine and wings, which I did. >=20 > When the gear is not spread, the tires set directly in the center "meat" o= f the tire. However, I have now noted...with the consequences, that as the g= ear spreads, there is a significant tilt to the inner edge of the tires thus= causing the wear. >=20 > The gear bow is provided in the Velocity kit and it quite sturdy. What am I= missing regarding the bow spread tilting the tire to the inside of the tire= , thus wearing in what would seem a less wear prone area? I am certain the c= amber was proper when the gear is not spreading out. I remember how tedious i= t was setting it, lowering the plane, checking, lifting, setting, lowering, c= hecking repeat a number of times to ensure the proper set (same goes to the t= oe-in process), but it is significant enough from the spread to roll the tir= e on the inner edge to cause a problem. >=20 > Before I drop a few hundred on new tire and tube and try to fly again, I w= ould like to figure out what I need to address. Is it just to re-set the cam= ber to be on the center meat of the tire when spread since this seems to be t= he case when taxiing or is there something else? >=20 > Insight guys???? Discuss. >=20 > Thanks, >=20 > Chris >=20 > cross posted to the canard aviation forum and the Velocity list as I know t= his is outside the scope of this list. --Apple-Mail-646B1F0B-3D09-41E0-B1AA-F9991E1E6A34 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 7bit
Chris, 

My 2 cents worth...  This sounds more line a toe-in /toe-out situation.  While it may be perfect while in a static state, it could go to a toe-out condition due to gear flex under hard braking.  Camber doesn't typically cause rapid tire wear, but toe-in / toe-out will.  

Mark


Sent from my iPad

On Jan 24, 2014, at 12:37 AM, Chris Barber <cbarber@texasattorney.net> wrote:

Well, on one hand I am pleased that when I did a quick loop of the pattern after I got off work this morning (I just switched to graveyard shift this week so get off work at 0700 hrs) my rotary ran smooth and strong and seemed to be producing pretty kick ass power.

HOWEVER, when I landed, I had my starboard tire blow out. Yes, it is quite the attention getter. I swayed slightly to the right of center of the runway at LVJ and luckily exited the taxiway closest to my hangar.

I was able to get it back to the hangar. No damage to the aircraft this time, not even the tire rim. But, I noted I had excessive wear on the inside of the tire.....much more than i would have expected with only 15 landings and less than seven hours of flight. I have done extensive taxi testing though (basically having and expensive go-cart)

I had noted on my conditional inspection that I had uneven wear but it did not seem that bad and I pledged to mind it. I concluded that the uneven wear on the inner tire was due to the gear spread that I had noticed on my and other canards (my hangar mate has a long easy and he is always lifting his bird to get the gear from spreading after taxi).

Velocity is pretty specific on how to set the camber and recommend you set the camber after installing the engine and wings, which I did.

When the gear is not spread, the tires set directly in the center "meat" of the tire. However, I have now noted...with the consequences, that as the gear spreads, there is a significant tilt to the inner edge of the tires thus causing the wear.

The gear bow is provided in the Velocity kit and it quite sturdy. What am I missing regarding the bow spread tilting the tire to the inside of the tire, thus wearing in what would seem a less wear prone area? I am certain the camber was proper when the gear is not spreading out. I remember how tedious it was setting it, lowering the plane, checking, lifting, setting, lowering, checking repeat a number of times to ensure the proper set (same goes to the toe-in process), but it is significant enough from the spread to roll the tire on the inner edge to cause a problem.

Before I drop a few hundred on new tire and tube and try to fly again, I would like to figure out what I need to address. Is it just to re-set the camber to be on the center meat of the tire when spread since this seems to be the case when taxiing or is there something else?

Insight guys???? Discuss.

Thanks,

Chris

cross posted to the canard aviation forum and the Velocity list as I know this is outside the scope of this list.
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