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Bent Nose Wheel Axle

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dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Wed Jul 21, 2010 8:13 pm Post subject: Bent Nose Wheel Axle

Recently, a hard landing resulted in a bent nose wheel axle. I was extremely

lucky as there was evidence that the tire made very light contact with the bolts

on the underside of the fork doubler / strut tube assembly. The tire basically

sprung back down away from making permanent contact and locking up which would

have been disastrous. There are plenty of pictures out there to see what

typically happens.... :0

After talking to ZAC about upgrading this axle tubing to something like solid

bar stock, I was told that the axle from the CH750 is the same size and is a solid

update to what I had for my 701. I ordered CH750 part number 75L1-5 and new

bolts and washers.

The date on my plans is June 30 2005 with the axle tube dimension .625" x

.058" wall tubing. I checked the 701 update list and found nothing to indicate

a change was made in this axle since my drawing date.



In the end, ZAC is kindly sending me a free axle.



Does anyone know or, has anyone used this "new" axle and can tell me if it is a

solid piece of bar stock as claimed or has at least a thicker tube wall than .058

thousandths??

PS: For safety's sake, inspect your nose wheel axles. To me the width

between the wheel bearings seems narrow relative to the span of the axle

required for tire width. The bearing hub of the wheel should be wider. Or was it

designed this way to absorb impact?

Thanks for you time, Don

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

kryptorm(at)bellsouth.net
Guest

Posted: Thu Jul 22, 2010 3:44 pm Post subject: Bent Nose Wheel Axle

Sorry to hear of your bent axle experience but I had the same misfortune about a year ago which resulted in several thousand dollars damage.  I had obviously bent the nose wheel axle while doing touch and goes at a rough grass strip and when I landed on a paved runway the wheel bent further and locked into the fork.  This resulted in the nose gear collapsing, lower firewall damage, and prop strike.  Fortunately my wife had insisted  that I insure the plane so most of the damage was covered.  I sent email to Chris Heinz with pictures of the bent axle complaining of this obvious weak link in an otherwise fine piece of engineering.  He responded expressing regret at my misfortune but stating hundreds of successful landings had been made on rough terrain without incident.  Well you, I, and many others disagree.  That piece of hollow pipe with two nuts welded on the end is a sad joke designed for for the sake of 1lb at the most.  I took my bent piece of tubing to a machine shop and had them manufacture a solid steel axle with threads on each end.  So much for feedback from Zenith.  Cheers 

On Thu, Jul 22, 2010 at 12:13 AM, dons701 <burdon1(at)comcast.net (burdon1(at)comcast.net)> wrote:

[quote] --> Zenith701801-List message posted by: "dons701" <burdon1(at)comcast.net (burdon1(at)comcast.net)>

 

 Recently, a hard landing resulted in a bent nose wheel axle. I was extremely

 lucky as there was evidence that the tire made very light contact with the bolts

 on the underside of the fork doubler / strut tube assembly. The tire basically

 sprung back down away from making permanent contact and locking up which would

 have been disastrous. There are plenty of pictures out there to see what

 typically happens.... :0

 After talking to ZAC about upgrading this axle tubing to something like solid

 bar stock, I was told that the axle from the CH750 is the same size and is a solid

 update to what I had for my 701. I ordered CH750 part number 75L1-5 and new

 bolts and washers.

 The date on my plans is June 30 2005 with the axle tube dimension .625" x

 .058" wall tubing. I checked the 701 update list and found nothing to indicate

 a change was made in this axle since my drawing date.

 

 In the end, ZAC is kindly sending me a free axle.

 

 Does anyone know or, has anyone used this "new" axle and can tell me if it is a

 solid piece of bar stock as claimed or has at least a thicker tube wall than .058

 thousandths??

 PS: For safety's sake, inspect your nose wheel axles. To me the width

 between the wheel bearings seems narrow relative to the span of the axle

 required for tire width. The bearing hub of the wheel should be wider. Or was it

 designed this way to absorb impact?

 Thanks for you time, Don

 

 --------

 Zenith 701 #76120

 Jabiru 2200A #2456  67 hours

 Sensenich Wood 64-PJ-36 Prop

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=305898#305898

 

 

 

 

 

 

 

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 [b]

dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Thu Jul 22, 2010 9:48 pm Post subject: Re: Bent Nose Wheel Axle

I have also posted this message at the Yahoo Groups to find out if anyone with a CH701 is using the "new" solid axle that was designed and is used on the heavier CH750. So far, no responses. Hopefully the UPS truck will land in my driveway Friday and I will see for myself how sturdy this new shaft is. 



   Another area of concern is the side flexing of the lower nose wheel fork where the axle is attached. This flexing has allowed the side wall of my tire to rub the inside of the fork if the nose wheel is not aligned with the runway, such as when needing to use the rudder till the nose sets down in a sudden crosswind. Admittedly, one should always maintain alignment but everyone knows this does not always happen. My possible solution would be to add triangular gussets to the wheel spacers that would extend upward from the spacer tubes and could attach to the two bolts currently used to join the aluminum forks as one. An additional bolt could be used midway, above the axle bolt. This would, I believe,  greatly stiffen the lower fork where axial side loads are delivered.

 Has anyone else experienced this ? Or has any comment on this ?

  All thoughts welcome... Don

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

John Bolding

Joined: 23 May 2006
Posts: 281

Posted: Fri Jul 23, 2010 4:34 am Post subject: Bent Nose Wheel Axle

Betcha this will stir the pot some,   In my never ending quest to shave #'s 

from my 701 under construction I've discovered that the nose wheel fork from 

a Cessna 150 will slip right on the 701 nose gear tube.  Of course you have 

to cut off the plate the Zenith fork bolts to.



Pros:

Complete assy , modified tube, fork, tire,wheel, axel is ALMOST 5# lighter 

than the plans built pieces.

Cost (to me anyway) was half , got my stuff from Air Salvage of Dallas.

Smaller tire means less drag and more importantly less forward mass, easier 

to balance a slightly heavier engine if you've refused to use a Rotax. 

PROBABLY less adverse yaw too but that is a WAG at this point.

GOTTA be stronger than the bent up plates, if Cessna uses it on an airplane 

several hundred pounds heavier than the 701 it outta work for us.



Cons:

You lose the "cool" factor of the tundra tire in the front. Fortunately I'm 

old enough to have gotten over all that foolishness. I've several hundred 

hours of beach, dirt road, cow pasture ect operation in an RV3 with 5:00x 5 

tires and for me to have one on the nose of a 701 which takes off 15-20 mph 

slower than the RV is a non-issue. If the plane is within CG you can taxi 

around with the nose wheel in the air anyway,  that's assuming you practice 

as much as Grant Rappe did.



I haven't measured EXACTLY but I don't think I'll have to remake the tube, 

even if I have to fab a new one a little longer, saving 5# is MONUMENTAL, 

especially on the front end. A no brainer for me.



There may be other hick-ups I haven't found  yet.



LO&SLO



John





---

zodierocket(at)hsfx.ca
Guest

Posted: Fri Jul 23, 2010 7:33 am Post subject: Bent Nose Wheel Axle

Excuse me for jumping in here then running to Oshkosh, every once in

awhile this topic comes up. The Older 960 gross 701 was designed for

lighter loads and used the smaller Azula wheels, just before the 1100

gross design change most people were installing 912's or heavier engines

and some people had issues with hard landings.



With today's 1100 gross designed STOL 701 and the Tundra tire I believe we

have one of the toughest and best designed systems out there in it's

weight class. The nose gear is designed to absord a tremendus amount of

energy before being deformed or causing damage to the firewall.



In Kitchener, we have used the STOL 701 for flight training for the past

12 years and yes students have really put the plane throgh it's pace. Over

that time the plane has been dropped from the air on several occasions, on

two seperate occasions it was pounded hrd enogh to actuall bend the main

landing gear, (Almost a 15-20 foot full stall above the runway). We

re-bent the main gear on one occasion adn replaced it on another. I have

watched teh 701 get wheelbarrowed down teh runway many a time and teh nose

gear holds up just fine. Rough feid landings are a pounder to any

aircraft's landing gear and we tend to land more on grass strips than

pavement, we  hold the weight of the nose off teh ground to smooh out the

ride down the strip.



Teh 701 is a rough little bird and handles it's itended purpose with

amzing grace, it peforms like no other plane can and we have nothing short

of a grand time with it. YES it does require a different skill set to

understand a



 	  Quote: 	
		   



 I have also posted this message at the Yahoo Groups to find out if anyone

 with a CH701 is using the "new" solid axle that was designed and is used

 on the heavier CH750. So far, no responses. Hopefully the UPS truck will

 land in my driveway Friday and I will see for myself how sturdy this new

 shaft is.



    Another area of concern is the side flexing of the lower nose wheel

 fork where the axle is attached. This flexing has allowed the side wall

 of my tire to rub the inside of the fork if the nose wheel is not

 aligned with the runway, such as when needing to use the rudder till

 the nose sets down in a sudden crosswind. Admittedly, one should always

 maintain alignment but everyone knows this does not always happen. My

 possible solution would be to add triangular gussets to the wheel

 spacers that would extend upward from the spacer tubes and could attach

 to the two bolts currently used to join the aluminum forks as one. An

 additional bolt could be used midway, above the axle bolt. This would,

 I believe,  greatly stiffen the lower fork where axial side loads are

 delivered.

  Has anyone else experienced this ? Or has any comment on this ?

   All thoughts welcome... Don



 --------

 Zenith 701 #76120

 Jabiru 2200A #2456  67 hours

 Sensenich Wood 64-PJ-36 Prop





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=306055#306055



 --

 This message has been scanned for viruses and

 dangerous content by MailScanner, and is

 believed to be clean.

zodierocket(at)hsfx.ca
Guest

Posted: Fri Jul 23, 2010 7:57 am Post subject: Bent Nose Wheel Axle

Sorry about the previous unfinished post, my laptop keyboard is not

working well and misses many of the keystrokes, which I edit before

release, The last message went by a wrong tap of the send key. Below is

the finished letter that has been quickly edited.



Mark

Excuse me for jumping in here then running off to Oshkosh, every once in

awhile this topic comes up. The Older 960 gross 701 was designed for

lighter loads and used the smaller Azula wheels, just before the 1100

gross design change most people were installing 912's or heavier engines

and some people had issues with hard landings, this stemmed more from

asking the design to operate beyond it's limits for extended periods.



With today's 1100 gross designed STOL 701 and the Tundra tires I believe we

have one of the toughest and best designed systems out there in it's

weight class. The nose gear is designed to absorb a tremendous amount of

energy before being deformed or causing damage to the firewall, the tundra

tires absorb an amazing amount of impact.



In Kitchener, we have used the STOL 701 for flight training for the past

12 years and yes students have really put the plane through it's pace. Over

that time the plane has been dropped from the air on several occasions, on

two separate occasions it was pounded hard enough to actually bend the main

landing gear, (Almost a 15-20 foot full stall above the runway). We

re-bent the main gear on one occasion and replaced it on another. I have

watched the 701 get wheelbarrowwed down the runway many a time and the nose

gear holds up just fine, I have seen students bounce the plane so high

that even Gus would b proud ( if you do not catch the jib, checkout You

tube for 701 with corvair) . Rough field landings are a pounder to any

aircraft's landing gear and we tend to land more on grass strips than

pavement, we  hold the weight of the nose off the ground to smooth out the

ride down the strip.



The 701 is a rough little bird and handles it's intended purpose with

amazing grace, it performs like no other plane can and we have nothing short

of a grand time with it. YES it does require a different skill set to

understand albeit not a difficult task to achieve. I believe this subject

is very similar to he VG issue, with knowledge, practice, the STOL 701 is

a perfectly and well designed plane that is better then a barrel of

Monkeys for fun. Also note that the bungee does have a 5 year life span ad

I have seen quite a few frayed and tired bungees over the years.



Now I am going to attach my bubble doors to our newest 701 and head to

Oshkosh. Hope to see you there.



Also check out

http://www.youtube.com/watch?v=s9mCkpw9nYE

http://www.youtube.com/watch?v=p74etfecaSk

See you at Oshkosh



Mark Townsend



[quote] 

 <jnbolding1(at)teleshare.net>



 Betcha this will stir the pot some,   In my never ending quest to shave

 #'s

 from my 701 under construction I've discovered that the nose wheel fork

 from

 a Cessna 150 will slip right on the 701 nose gear tube.  Of course you

 have

 to cut off the plate the Zenith fork bolts to.



 Pros:

 Complete assy , modified tube, fork, tire,wheel, axel is ALMOST 5# lighter

 than the plans built pieces.

 Cost (to me anyway) was half , got my stuff from Air Salvage of Dallas.

 Smaller tire means less drag and more importantly less forward mass,

 easier

 to balance a slightly heavier engine if you've refused to use a Rotax.

 PROBABLY less adverse yaw too but that is a WAG at this point.

 GOTTA be stronger than the bent up plates, if Cessna uses it on an

 airplane

 several hundred pounds heavier than the 701 it outta work for us.



 Cons:

 You lose the "cool" factor of the tundra tire in the front. Fortunately

 I'm

 old enough to have gotten over all that foolishness. I've several hundred

 hours of beach, dirt road, cow pasture ect operation in an RV3 with 5:00x

 5

 tires and for me to have one on the nose of a 701 which takes off 15-20

 mph

 slower than the RV is a non-issue. If the plane is within CG you can taxi

 around with the nose wheel in the air anyway,  that's assuming you

 practice

 as much as Grant Rappe did.



 I haven't measured EXACTLY but I don't think I'll have to remake the tube,

 even if I have to fab a new one a little longer, saving 5# is MONUMENTAL,

 especially on the front end. A no brainer for me.



 There may be other hick-ups I haven't found  yet.



 LO&SLO



 John





 ---

dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Fri Jul 23, 2010 8:14 am Post subject: Re: Bent Nose Wheel Axle

Hi John, this site needs a little pot stirring. 



        I like your idea as I have been thinking of ways to improve the nose gear for some time. The current design works well as it has been used for a long time, but could use some help. Somewhere in the net I have seen a 701 with what looked like a pair of front forks and wheel from a dirt bike. Crazy I know but, if strong enough, this would provide an adjustable spring rate and hydraulic dampening. I have seen pictures here on this site where a small coil over shock was installed inside the top of the nose gear strut on an 801, I have not read how well it worked though but others are trying.

       I will admit that I am a relative amateur with flying the 701 but, I have walked on this earth long enough to know some things need improvement based on the problems encountered by me and others. 

       The 701 is a rugged plane as is and with care can be improved.

      Don

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

kryptorm(at)bellsouth.net
Guest

Posted: Fri Jul 23, 2010 9:21 am Post subject: Bent Nose Wheel Axle

Good luck with the 701708 nose wheel axle.  The nose gear may be "designed to absorb a tremendous amount of energy" but that will not prevent substantial damage if the front tire locks on the fork due to a bent axle read (hollow tube with nuts welded to both ends).   A close inspection of this Zenith part during pre-flight can not be over emphasised. 



On Fri, Jul 23, 2010 at 11:33 AM,  <zodierocket(at)hsfx.ca (zodierocket(at)hsfx.ca)> wrote:

[quote] --> Zenith701801-List message posted by: zodierocket(at)hsfx.ca (zodierocket(at)hsfx.ca)

 

 Excuse me for jumping in here then running to Oshkosh, every once in

 awhile this topic comes up. The Older 960 gross 701 was designed for

 lighter loads and used the smaller Azula wheels, just before the 1100

 gross design change most people were installing 912's or heavier engines

 and some people had issues with hard landings.

 

 With today's 1100 gross designed STOL 701 and the Tundra tire I believe we

 have one of the toughest and best designed systems out there in it's

 weight class. The nose gear is designed to absord a tremendus amount of

 energy before being deformed or causing damage to the firewall.

 

 In Kitchener, we have used the STOL 701 for flight training for the past

 12 years and yes students have really put the plane throgh it's pace. Over

 that time the plane has been dropped from the air on several occasions, on

 two seperate occasions it was pounded hrd enogh to actuall bend the main

 landing gear, (Almost a 15-20 foot full stall above the runway). We

 re-bent the main gear on one occasion adn replaced it on another. I have

 watched teh 701 get wheelbarrowed down teh runway many a time and teh nose

 gear holds up just fine. Rough feid landings are a pounder to any

 aircraft's landing gear and we tend to land more on grass strips than

 pavement, we  hold the weight of the nose off teh ground to smooh out the

 ride down the strip.

 

 Teh 701 is a rough little bird and handles it's itended purpose with

 amzing grace, it peforms like no other plane can and we have nothing short

 of a grand time with it. YES it does require a different skill set to

 understand a

 



 

 

 > --> Zenith701801-List message posted by: "dons701" <burdon1(at)comcast.net (burdon1(at)comcast.net)>

 >

 > I have also posted this message at the Yahoo Groups to find out if anyone

 > with a CH701 is using the "new" solid axle that was designed and is used

 > on the heavier CH750. So far, no responses. Hopefully the UPS truck will

 > land in my driveway Friday and I will see for myself how sturdy this new

 > shaft is.

 >

 >    Another area of concern is the side flexing of the lower nose wheel

 > fork where the axle is attached. This flexing has allowed the side wall

 > of my tire to rub the inside of the fork if the nose wheel is not

 > aligned with the runway, such as when needing to use the rudder till

 > the nose sets down in a sudden crosswind. Admittedly, one should always

 > maintain alignment but everyone knows this does not always happen. My

 > possible solution would be to add triangular gussets to the wheel

 > spacers that would extend upward from the spacer tubes and could attach

 > to the two bolts currently used to join the aluminum forks as one. An

 > additional bolt could be used midway, above the axle bolt. This would,

 > I believe,  greatly stiffen the lower fork where axial side loads are

 > delivered.

 >  Has anyone else experienced this ? Or has any comment on this ?

 >   All thoughts welcome... Don

 >

 > --------

 > Zenith 701 #76120

 > Jabiru 2200A #2456  67 hours

 > Sensenich Wood 64-PJ-36 Prop

 >

 >

 >

 >

 > Read this topic online here:

 >

 > http://forums.matronics.com/viewtopic.php?p=306055#306055

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 



 	  Quote: 	
		   --

 > This message has been scanned for viruses and
	


 > dangerous content by MailScanner, and is

 > believed to be clean.

 

 	  Quote: 	
		  

 
	


 

 ===========

 -List" target="_blank">http://www.matronics.com/Navigator?Zenith701801-List

 ===========

 http://forums.matronics.com

 ===========

 le, List Admin.

 ="_blank">http://www.matronics.com/contribution

 ===========

 

 

 

 



[b]

Curt.Thompson(at)verizon.
Guest

Posted: Fri Jul 23, 2010 10:37 am Post subject: Bent Nose Wheel Axle

Here is a longer video of the one that Mark sent.  It shows the damage.



http://www.youtube.com/watch?v=17yKXFAlqjk&feature=related

Curt



--

Curt.Thompson(at)verizon.
Guest

Posted: Fri Jul 23, 2010 10:51 am Post subject: Bent Nose Wheel Axle

Looks to me like the bolt holding the fork on failed.  Firewall pretty bent

up.



Curt



--

dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Fri Jul 23, 2010 2:53 pm Post subject: Re: Bent Nose Wheel Axle

Notice the curved sheet aluminum brace attached around the gear strut fire wall stiffener. Don

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

Roland Smith

Joined: 02 Jul 2006
Posts: 14

Posted: Sun Jul 25, 2010 4:02 am Post subject: Re: Bent Nose Wheel Axle

Sure, I've bent the front wheel axle-- twice in the first 50 hours.  My friends suggested that I try landing on the rear wheels.  The second axle I got from Zenith is solid. Have'nt bent it yet.   I got the impression from Z that the axle is a good seller. Other observations from my buddies include "it might be better to 'sacrifice' an axle than something  more costly; consider thicker sleeves; stop trying to emulate 'Canyon Flying'..."    I also note that Matco has a 5/8 wheel bearing, which, of course, would require a different axle but might defeat the idea of a 'sacrifical' part in case of a bad landing.



Really nice to know that I'm not the only one.

_________________
701 kit, Rotax 912 ULS, SensorNetics EFIS, Flying.

dons701

Joined: 22 May 2009
Posts: 80
Location: Hershey, PA

Posted: Sun Jul 25, 2010 7:07 am Post subject: Re: Bent Nose Wheel Axle

Hi Roland,



    Friends are great are'nt they, "try landing on the rear wheels"... I will agree though on the fact that the bending of the axle helps to absorb energy, the unfortunate consequence if bent hard enough is wheel lock up. During the inspection I was shocked to see how close the tire was to the bolt heads where the forks attach to the strut tube. I thought, that was darn close ! It was just then I noticed there were light grooves in the tread of my tire, right in line with the bolt heads!!



    The axle is already 5/8" (.625), so I will guess you meant to say 3/4" and will require a different axle?

_________________
Zenith 701 #76120
Jabiru 2200A #2456 95 hours
Sensenich Wood 64-PJ-36 Prop

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