Have you ever seen this ? Webra 160 cracked!
11-24-2007, 07:43 PM
#3
My Feedback: (16)
Join Date: Jul 2002
Location: tulsa,
OK
Posts: 574
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Have you thought about JB Weld to fix it?.........
Just kidding, whats the warranty on those was thinking it was 2 years.
Just kidding, whats the warranty on those was thinking it was 2 years.
11-24-2007, 07:51 PM
#4
Senior Member
Join Date: Dec 2002
Location: USA
Posts: 2,035
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
How tight is that nose ring?
For all the world the pictures make it look like that might have caused it. Pure guess work but that is how it looks.
Or, IF the mount is soft then even a slightly firm ring would have transferred the force to that spot.
As I said pure guess work--------------
---and NO, I have never seen any engine fail that way.
For all the world the pictures make it look like that might have caused it. Pure guess work but that is how it looks.
Or, IF the mount is soft then even a slightly firm ring would have transferred the force to that spot.
As I said pure guess work--------------
---and NO, I have never seen any engine fail that way.
11-24-2007, 09:02 PM
#5
Senior Member
My Feedback: (25)
Join Date: Mar 2002
Posts: 1,579
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Mark,
I'm not sure if you know Bill Mitchell that flies Advanced in our area, but he had a 1.60 case crack. I can't remember if it was there or right along the mounting flanges.
In case you don't know, Terry Darr is a whiz with those motors. If you want to talk with him about it, I'll give you his number. Have Dale Arnold look at it, he may tell you to talk to Terry, or you may be better off just getting a new case.
That sucks that happened.
I'm not sure if you know Bill Mitchell that flies Advanced in our area, but he had a 1.60 case crack. I can't remember if it was there or right along the mounting flanges.
In case you don't know, Terry Darr is a whiz with those motors. If you want to talk with him about it, I'll give you his number. Have Dale Arnold look at it, he may tell you to talk to Terry, or you may be better off just getting a new case.
That sucks that happened.
11-24-2007, 09:49 PM
#8
Senior Member
RE: Have you ever seen this ? Webra 160 cracked!
ORIGINAL: mtcarey
Running Coolpower 10%. APC 17 X 12 prop. About 300 flights. ALWAYS run rich. Engine 18 months old.
Running Coolpower 10%. APC 17 X 12 prop. About 300 flights. ALWAYS run rich. Engine 18 months old.
MattK
11-24-2007, 10:29 PM
#9
My Feedback: (2)
Join Date: Feb 2003
Location: Palm Bay, FL
Posts: 1,046
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Yes. I got one of those last year.
Horizon replaced it no questions. Webra must've had a few defects.
I've heard of another one....I think maybe Brian Billings in Jacksonville...?
-Ron
Horizon replaced it no questions. Webra must've had a few defects.
I've heard of another one....I think maybe Brian Billings in Jacksonville...?
-Ron
11-25-2007, 01:09 PM
#11
Senior Member
Join Date: Mar 2003
Location: Teesside, UNITED KINGDOM
Posts: 134
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Sorry to hear about your problem.
OneWasp made a good point when he asked how tight the nose ring was.
After a while, rubber ‘O’ Rings tend to grip ferociously to alloy crankcases, especially if the mating area is non-machined. If the mount is fairly soft, the rear engine will be trying to rotate and an ‘O’ Ring that is gripping tightly would be trying to prevent this. This would result in a large couple being applied to the front end of the crankcase, just at the point where it failed!
Although I ran a Webra 160 for a short period, most of my recent experience has been with YS Dingos. The ‘O’ Ring bearing surface on a YS is machined. Despite this, on more recent engines, YS have taken the additional precaution of adding a thin wrap of tape (with a shiny surface similar to brown parcel tape) to further reduce the friction between the ‘O’ Ring and the crankcase. For good measure, I also ensure that the ‘O’ Ring is well lubricated with silicon grease before I fit it. Apart from anything else, it makes the ring easier to remove when the time comes.
I note your point about not experiencing any problems with the original engine. However I would still recommended that you fit a thin wrap of parcel tape to the front of your new crankcase and that you add some silicon grease to the new ‘O’ Ring before re-installing it.
Best of luck.
Bob Wasson
OneWasp made a good point when he asked how tight the nose ring was.
After a while, rubber ‘O’ Rings tend to grip ferociously to alloy crankcases, especially if the mating area is non-machined. If the mount is fairly soft, the rear engine will be trying to rotate and an ‘O’ Ring that is gripping tightly would be trying to prevent this. This would result in a large couple being applied to the front end of the crankcase, just at the point where it failed!
Although I ran a Webra 160 for a short period, most of my recent experience has been with YS Dingos. The ‘O’ Ring bearing surface on a YS is machined. Despite this, on more recent engines, YS have taken the additional precaution of adding a thin wrap of tape (with a shiny surface similar to brown parcel tape) to further reduce the friction between the ‘O’ Ring and the crankcase. For good measure, I also ensure that the ‘O’ Ring is well lubricated with silicon grease before I fit it. Apart from anything else, it makes the ring easier to remove when the time comes.
I note your point about not experiencing any problems with the original engine. However I would still recommended that you fit a thin wrap of parcel tape to the front of your new crankcase and that you add some silicon grease to the new ‘O’ Ring before re-installing it.
Best of luck.
Bob Wasson
11-25-2007, 07:36 PM
#12
Senior Member
RE: Have you ever seen this ? Webra 160 cracked!
ORIGINAL: Wasson
Sorry to hear about your problem.
OneWasp made a good point when he asked how tight the nose ring was.
After a while, rubber ‘O’ Rings tend to grip ferociously to alloy crankcases, especially if the mating area is non-machined. If the mount is fairly soft, the rear engine will be trying to rotate and an ‘O’ Ring that is gripping tightly would be trying to prevent this. This would result in a large couple being applied to the front end of the crankcase, just at the point where it failed!
Although I ran a Webra 160 for a short period, most of my recent experience has been with YS Dingos. The ‘O’ Ring bearing surface on a YS is machined. Despite this, on more recent engines, YS have taken the additional precaution of adding a thin wrap of tape (with a shiny surface similar to brown parcel tape) to further reduce the friction between the ‘O’ Ring and the crankcase. For good measure, I also ensure that the ‘O’ Ring is well lubricated with silicon grease before I fit it. Apart from anything else, it makes the ring easier to remove when the time comes.
I note your point about not experiencing any problems with the original engine. However I would still recommended that you fit a thin wrap of parcel tape to the front of your new crankcase and that you add some silicon grease to the new ‘O’ Ring before re-installing it.
Best of luck.
Bob Wasson
Sorry to hear about your problem.
OneWasp made a good point when he asked how tight the nose ring was.
After a while, rubber ‘O’ Rings tend to grip ferociously to alloy crankcases, especially if the mating area is non-machined. If the mount is fairly soft, the rear engine will be trying to rotate and an ‘O’ Ring that is gripping tightly would be trying to prevent this. This would result in a large couple being applied to the front end of the crankcase, just at the point where it failed!
Although I ran a Webra 160 for a short period, most of my recent experience has been with YS Dingos. The ‘O’ Ring bearing surface on a YS is machined. Despite this, on more recent engines, YS have taken the additional precaution of adding a thin wrap of tape (with a shiny surface similar to brown parcel tape) to further reduce the friction between the ‘O’ Ring and the crankcase. For good measure, I also ensure that the ‘O’ Ring is well lubricated with silicon grease before I fit it. Apart from anything else, it makes the ring easier to remove when the time comes.
I note your point about not experiencing any problems with the original engine. However I would still recommended that you fit a thin wrap of parcel tape to the front of your new crankcase and that you add some silicon grease to the new ‘O’ Ring before re-installing it.
Best of luck.
Bob Wasson
I believe that the tape material YS uses is actually teflon tape. This item is easy to purchase directly from McMaster Carr or other industrial supply house. The adhesive used on the tape adheres the tape just fine to the crankcase bearing housing.
I wonder whether the standard nose rings available on the market provide adequate protection to the engine. The o-rings used may not offer enough rubber for adequate snubbing, with possibly too much force transmitted to the aluminum base. It's supposed to be strictly rotational at the nose, but maybe there is enought translational load to be a problem in some installations
I prefer making my nose rings completely from rubber sheet stock, thus avoiding any of these issues. They serve to snub and mount the nose to the airplane. No aluminum is used. FWIW
MattK
11-26-2007, 02:17 AM
#13
Join Date: Mar 2005
Location: Saffron Walden, UNITED KINGDOM
Posts: 563
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
It just might,not be the nose ring causing the problem.
When we were using 61 two-strokes, it became fairly standard practice,to soft-mount them,via an aluminium plate bolted to the backplate, with four lord-type rubber mounts fixed to the firewall.
When the bigger two-strokes came in, it seems that with the longer cranckcase/bigger props/whatever, this method was no longer viable long-term.
I had a few broken crankcases with Irvine 150 mk1s, a few cases or crankshafts with ST 2300s,but,being a flyer rather than a thinker,or engineer,and given the relative cheapness of the motors,did the "American" thing, and "got another one out of the van"(cf Ford GT40s at Le Mans?)
When the same thing happened to my OS160 crankshafts after maybe ten flights from new, I changed to rigid aluminium beams bolted to the usual lugs on the case,still fixed to the firewall via lord mounts, and absolutely no problems since (and no apparent need for a nose ring,btw.).
Looking at the photo, the beams look like fairly flimsy folded alloy----could it be that they are allowing the crankcase to flex too much,as it seems was the weakness in my earlier system?
When we were using 61 two-strokes, it became fairly standard practice,to soft-mount them,via an aluminium plate bolted to the backplate, with four lord-type rubber mounts fixed to the firewall.
When the bigger two-strokes came in, it seems that with the longer cranckcase/bigger props/whatever, this method was no longer viable long-term.
I had a few broken crankcases with Irvine 150 mk1s, a few cases or crankshafts with ST 2300s,but,being a flyer rather than a thinker,or engineer,and given the relative cheapness of the motors,did the "American" thing, and "got another one out of the van"(cf Ford GT40s at Le Mans?)
When the same thing happened to my OS160 crankshafts after maybe ten flights from new, I changed to rigid aluminium beams bolted to the usual lugs on the case,still fixed to the firewall via lord mounts, and absolutely no problems since (and no apparent need for a nose ring,btw.).
Looking at the photo, the beams look like fairly flimsy folded alloy----could it be that they are allowing the crankcase to flex too much,as it seems was the weakness in my earlier system?
11-26-2007, 07:35 PM
#14
My Feedback: (16)
Join Date: Jul 2002
Location: tulsa,
OK
Posts: 574
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
I used a grommet like that as a nose ring on my webras as well. I didnt have that extended nose ring but was in a more conventional fiberglass plane. I wonder how rigid that arrangement is to cause the case to crack, but I can see if you have the case cantilievered and the mount etc is crooked...say to add down thrust but the nose ring isnt adjusted to accomodate the offset...it might put a load on the case and being aluminum it doesnt like repetitive high stresses and eventually fatigues and cracks. Result what you see here. It looks like the crack is gapped more at the bottom of the engine case, being mounted inverted this wide spot faces up in the plane, kind of why I thought of the above. ............thats my best long distance geuss.
11-27-2007, 09:15 AM
#15
Senior Member
My Feedback: (2)
Join Date: Mar 2002
Location: Orange Park,
FL
Posts: 262
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Been there done that, here is a few pics of my 160 that broke at the d3 champs last year. Jon Lowe has had an OS160 fail in the exact same manner as well, he had lost a prop blade on his prior to the failure.
http://www.billingsauto.smugmug.com/...2044287#P-11-9
http://www.billingsauto.smugmug.com/...2044287#P-11-9
11-27-2007, 11:46 AM
#16
Senior Member
RE: Have you ever seen this ? Webra 160 cracked!
ORIGINAL: BrianB
Been there done that, here is a few pics of my 160 that broke at the d3 champs last year. Jon Lowe has had an OS160 fail in the exact same manner as well, he had lost a prop blade on his prior to the failure.
http://www.billingsauto.smugmug.com/...2044287#P-11-9
Been there done that, here is a few pics of my 160 that broke at the d3 champs last year. Jon Lowe has had an OS160 fail in the exact same manner as well, he had lost a prop blade on his prior to the failure.
http://www.billingsauto.smugmug.com/...2044287#P-11-9
The only time before all of this I had ever seen a cracked case was when a con-rod sheared the pin and drove through the side of an OS61 re fsr, 20 years ago or more. It looks like trying to make these large engines as light as possible has possibly caused thinning the case walls a bit too much. Machined bar stock, ala Mintor, is better, stronger
Curious...what soft mount were all of you guys who lost crankcases using? Or were they softly mounted at all? It looks like it's just a matter of time before some more engines break cases
MattK
11-27-2007, 12:56 PM
#17
Senior Member
My Feedback: (25)
Join Date: Mar 2002
Posts: 1,579
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Matt, the aftormentioned broken case on my friend Bill's motor was with a Hyde ARA mount. It looks like Mark is using a Budd mount. Could the common denominator be metal beams on motor mounts?
11-27-2007, 05:40 PM
#18
Join Date: Mar 2005
Location: Saffron Walden, UNITED KINGDOM
Posts: 563
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
Could the common denominator be metal beams on motor mounts?
My original mount system(backplate carrying ali plate, plate carrying four lord-type rubber bobbins bolted to firewall) worked fine on 61s, but the extra crankcase length and bigger props on Irvine 150s,ST2300s,OS160s, all resulted in broken cases and /or crankshafts.
Changing to conventional cast aluminium beam mounts(again connected to the firewall via lord mounts) completely eliminated the problem.
11-27-2007, 07:07 PM
#19
Senior Member
RE: Have you ever seen this ? Webra 160 cracked!
ORIGINAL: f3a05
Not in my cases(Pun intended), no.
My original mount system(backplate carrying ali plate, plate carrying four lord-type rubber bobbins bolted to firewall) worked fine on 61s, but the extra crankcase length and bigger props on Irvine 150s,ST2300s,OS160s, all resulted in broken cases and /or crankshafts.
Changing to conventional cast aluminium beam mounts(again connected to the firewall via lord mounts) completely eliminated the problem.
Could the common denominator be metal beams on motor mounts?
My original mount system(backplate carrying ali plate, plate carrying four lord-type rubber bobbins bolted to firewall) worked fine on 61s, but the extra crankcase length and bigger props on Irvine 150s,ST2300s,OS160s, all resulted in broken cases and /or crankshafts.
Changing to conventional cast aluminium beam mounts(again connected to the firewall via lord mounts) completely eliminated the problem.
Interesting. On the other hand, most large gas engines are mounted as you describe....rear of the crankcase. Their shafts are even longer and massive than the standard Pattern engine fare. These are typically hard mounted to a firewall or other box type assembly and crankcase failures of the type disclosed herein in the thread do not happen.
The mode of failure has another root cause. I suspect the cause to be thin castings. The more I think about it, the more I like the Mintor machined bar stock cases. Alas, the Mintor engine doesn't cut it with the consistency we demand but their choices in materials of construction offer real advantages.
MattK
11-27-2007, 08:19 PM
#20
My Feedback: (2)
Join Date: Feb 2003
Location: Palm Bay, FL
Posts: 1,046
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
In my case, the engine was mounted on a regular plastic arm (Sig) Hyde mount with a ply/fuel tubing nose ring.
Nothing exotic at all.
I've got three of these engines and I think a lot of 'em. Light, powerful, and inexpensive. IMHO this is a minor issue as long as the product is backed up by Webra and it's distributors. As I said before, Horizon treated me well and I intend to keep using them.
-Ron
Nothing exotic at all.
I've got three of these engines and I think a lot of 'em. Light, powerful, and inexpensive. IMHO this is a minor issue as long as the product is backed up by Webra and it's distributors. As I said before, Horizon treated me well and I intend to keep using them.
-Ron
11-27-2007, 09:01 PM
#21
Senior Member
RE: Have you ever seen this ? Webra 160 cracked!
ORIGINAL: grotto2
In my case, the engine was mounted on a regular plastic arm (Sig) Hyde mount with a ply/fuel tubing nose ring.
Nothing exotic at all.
I've got three of these engines and I think a lot of 'em. Light, powerful, and inexpensive. IMHO this is a minor issue as long as the product is backed up by Webra and it's distributors. As I said before, Horizon treated me well and I intend to keep using them.
-Ron
In my case, the engine was mounted on a regular plastic arm (Sig) Hyde mount with a ply/fuel tubing nose ring.
Nothing exotic at all.
I've got three of these engines and I think a lot of 'em. Light, powerful, and inexpensive. IMHO this is a minor issue as long as the product is backed up by Webra and it's distributors. As I said before, Horizon treated me well and I intend to keep using them.
-Ron
Matt
11-27-2007, 09:22 PM
#23
Senior Member
Join Date: Dec 2002
Location: USA
Posts: 2,035
Likes: 0
Received 0 Likes
on
0 Posts
RE: Have you ever seen this ? Webra 160 cracked!
To the best of my knowledge that is a fact-----PAST tense----certainly in the 'Pattern' sizes.
Check their site----just parts and a Heli engine that's it.
Check their site----just parts and a Heli engine that's it.
11-28-2007, 12:30 PM
#24
RE: Have you ever seen this ? Webra 160 cracked!
I sent the engine back to Horizon, waiting to here what they say. The rubber grommet is thicker and softer than the others I've seen. It's Buna-N Rubber about as soft as the gromments on your servos. Also the 4 carbon fiber braces are arrange to resist vertical and horizontal movement but do move to some degree in a rotational manner with the engine.
