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johngilpin
Joined: 23 Mar 2011
Posts: 93
Location: 004
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 Posted: Fri Feb 22, 2013 12:48 am Post subject: Tailwheel upgrade |
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Yeh, a tailwheel upgrade is really worthwhile. That pizza cutter is pathetic...
For my Firefly, I got the one from Aircraft Spruce because it was in stock for immediate shipment and Kolb didn’t have any in stock at that time. Bad mistake..... The one from Spruce has 1/2” hole, while the Kolb shaft is 5/8”..... It’s a specialized machining job to bore it out because there’s a square boss that won’t chuck in a lathe. I took it to a really well-equipped machine shop and they found it difficult. They had to load it in the chuck from the driven end, then the work was so buried in the chuck that a conventional boring bar wouldn’t reach, so they had to fabricate a special extension. Cost $130 for 1 1/2 hrs work...... So if your going to get that tailwheel assembly, get from Kolb and it’s all ready to go.
But to do it again I wouldn’t get that assembly at all. As Larry has pointed out, that breakaway swivel is a pain.... I also had to machine out the mechanism so that it doesn’t breakaway. So what’s the point of paying for all that mechanism at all. Besides, that tailwheel is heavy and designed for much heavier aircraft. Another problem with that product is that the steering arms are much longer than the original, so it gives even less deflection at full lock. The arm is very hard steel and I couldn’t drill it to shorten the arms. Maybe if you heated and annealed at that point you could drill it....
The original Kolb mechanism is a lot lighter and is adequate, it’s only the pizza cutter wheel itself that’s the problem...... I noticed that the bearings in the new tail wheel would fit onto the the original Kolb tailwheel axle. Only problem was that the axle is too short to project all the way through the new wheel. To do it again I’d have a longer axle welded in place on the original gear, and just replace the wheel. Surely the wheel itself must be available as a replacement part.
Hopefully Kolb could source those wheels and manufacture the part to just bolt it onto their original gear. Be a lot easier and less costly....
JG
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neilsenrm(at)gmail.com
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| Posted: Fri Feb 22, 2013 7:47 am Post subject: Tailwheel upgrade |
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John
I can't speak for the Spruce version but the Kolb version is worth every penny but it to needs to be modified to work well. First get some compression springs. The light springs allow the tail wheel to rotate in a strong cross wind situation that allows it to unlock at just the wrong time. Then you need to cut (shorten) and drill thesteeringarms so that you can get enough rotation to unlock the tail wheel at full rudder defection. These tail wheels don't unlock till they are turned quite a bit. Also you need to find a good tool store thatsellsdrill bits for hard steel.
Rick Neilsen
Redrive VW Powered MKIIIC
On Sat, Sep 15, 2012 at 11:25 AM, John Gilpin <j.gilpin(at)bigpond.com (j.gilpin(at)bigpond.com)> wrote:
[quote] Yeh, a tailwheel upgrade is really worthwhile. That pizza cutter is pathetic...
For my Firefly, I got the one from Aircraft Spruce because it was in stock for immediate shipment and Kolb didnt have any in stock at that time. Bad mistake..... The one from Spruce has 1/2 hole, while the Kolb shaft is 5/8..... Its a specialized machining job to bore it out because theres a square boss that wont chuck in a lathe. I took it to a really well-equipped machine shop and they found it difficult. They had to load it in the chuck from the driven end, then the work was so buried in the chuck that a conventional boring bar wouldnt reach, so they had to fabricate a special extension. Cost $130 for 1 1/2 hrs work...... So if your going to get that tailwheel assembly, get from Kolb and its all ready to go.
But to do it again I wouldnt get that assembly at all. As Larry has pointed out, that breakaway swivel is a pain.... I also had to machine out the mechanism so that it doesnt breakaway. So whats the point of paying for all that mechanism at all. Besides, that tailwheel is heavy and designed for much heavier aircraft. Another problem with that product is that the steering arms are much longer than the original, so it gives even less deflection at full lock. The arm is very hard steel and I couldnt drill it to shorten the arms. Maybe if you heated and annealed at that point you could drill it....
The original Kolb mechanism is a lot lighter and is adequate, its only the pizza cutter wheel itself thats the problem...... I noticed that the bearings in the new tail wheel would fit onto the the original Kolb tailwheel axle. Only problem was that the axle is too short to project all the way through the new wheel. To do it again Id have a longer axle welded in place on the original gear, and just replace the wheel. Surely the wheel itself must be available as a replacement part.
Hopefully Kolb could source those wheels and manufacture the part to just bolt it onto their original gear. Be a lot easier and less costly....
JG
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byoungplumbing(at)gmail.c
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| Posted: Fri Feb 22, 2013 8:57 am Post subject: Tailwheel upgrade |
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I dont know what I am missing.... if you drill the arms so you have more deflection, then machine out the fitting so it takes more deflection to break it loose... where is the benefit. I put on a full swivel tail wheel and never looked back. it is wonderful. in normal driving I have never had it break away. if I want it to break, even with the longer arms all I have to do is add a bit of breaking and that forces it over the edge. I am still using the light stock springs with the longer arms and have not noticed any more problems in a cross wind than I had on the pizza cutter wheel. I dont know if it just comes down to technique, but in a cross wind I have been conscious of riding the break a bit. I only had one time when I could not hold a line... that was in a 25 gusting to 35 wind at a 90 deg to my direction of taxi. the tail wheel was firmly attached to the ground... I just think it would skid sideward when the gust would hit the tail. only a tire with more grip would have eliminated that problem.
boyd young
mkiii utah
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I can't speak for the Spruce version but the Kolb version is worth every penny but it to needs to be modified to work well. First get some compression springs. The light springs allow the tail wheel to rotate in a strong cross wind situation that allows it to unlock at just the wrong time. Then you need to cut (shorten) and drill the steering arms so that you can get enough rotation to unlock the tail wheel at full rudder defection. These tail wheels don't unlock till they are turned quite a bit. Also you need to find a good tool store that sells drill bits for hard steel.
For my Firefly, I got the one from Aircraft Spruce because it was in stock for immediate shipment and Kolb didnt have any in stock at that time. Bad mistake..... The one from Spruce has 1/2 hole, while the Kolb shaft is 5/8..... Its a specialized machining job to bore it out because theres a square boss that wont chuck in a lathe. I took it to a really well-equipped machine shop and they found it difficult. They had to load it in the chuck from the driven end, then the work was so buried in the chuck that a conventional boring bar wouldnt reach, so they had to fabricate a special extension. Cost $130 for 1 1/2 hrs work...... So if your going to get that tailwheel assembly, get from Kolb and its all ready to go.
[quote][b]
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neilsenrm(at)gmail.com
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| Posted: Fri Feb 22, 2013 9:48 am Post subject: Tailwheel upgrade |
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Boyd
On a cross country the wind picked up don't know the speed now but it was strong. I landed for gas and had totaxi cross wind. Holding fulloppositerudder and one wheel breakinga gust would push the tail wheel (stretchingthe weak springs) to the point where it unlocked three times (doing a 360 to get it to lock again) to the gas pumps then 5-6 more times to get to a sheltered area. The compression springs fixed the unlocking problem but they also didn't allow the tail wheel to rotate enough to unlock ever. The optional tail wheel has much longer arms than the stock "bogey" wheeltail wheel assembly. I then shortened to tail wheel control arms and spring attach points to get enough rotation to get a full deflection unlock. Now I get very positive control of the tail wheel and the wheel will unlock only when the rudder hits the stop. There have been a few times where wind gusts have pushed thetail wheelsidewaysbut I was able to recover without having to do a 360 and I don't have to ride the brakes. Note! I did not "machine out the fitting".
Rick Neilsen
Redrive VW Powered MKIIIC
On Fri, Feb 22, 2013 at 11:57 AM, b young <byoungplumbing(at)gmail.com (byoungplumbing(at)gmail.com)> wrote:
[quote] I dont know what I am missing.... if you drill the arms so you have more deflection, then machine out the fitting so it takes more deflection to break it loose... where is the benefit. I put on a full swivel tail wheel and never looked back. it is wonderful. in normal driving I have never had it break away. if I want it to break, even with the longer arms all I have to do is add a bit of breaking and that forces it over the edge. I am still using the light stock springs with the longer arms and have not noticed any more problems in a cross wind than I had on the pizza cutter wheel. I dont know if it just comes down to technique, but in a cross wind I have been conscious of riding the break a bit. I only had one time when I could not hold a line... that was in a 25 gusting to 35 wind at a 90 deg to my direction of taxi. the tail wheel was firmly attached to the ground... I just think it would skid sideward when the gust would hit the tail. only a tire with more grip would have eliminated that problem.
boyd young
mkiii utah
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I can't speak for the Spruce version but the Kolb version is worth every penny but it to needs to be modified to work well. First get some compression springs. The light springs allow the tail wheel to rotate in a strong cross wind situation that allows it to unlock at just the wrong time. Then you need to cut (shorten) and drill the steering arms so that you can get enough rotation to unlock the tail wheel at full rudder defection. These tail wheels don't unlock till they are turned quite a bit. Also you need to find a good tool store that sells drill bits for hard steel.
For my Firefly, I got the one from Aircraft Spruce because it was in stock for immediate shipment and Kolb didnt have any in stock at that time. Bad mistake..... The one from Spruce has 1/2 hole, while the Kolb shaft is 5/8..... Its a specialized machining job to bore it out because theres a square boss that wont chuck in a lathe. I took it to a really well-equipped machine shop and they found it difficult. They had to load it in the chuck from the driven end, then the work was so buried in the chuck that a conventional boring bar wouldnt reach, so they had to fabricate a special extension. Cost $130 for 1 1/2 hrs work...... So if your going to get that tailwheel assembly, get from Kolb and its all ready to go.
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tp://forums.matronics.com
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tombaisley
Joined: 20 Jan 2012
Posts: 30
Location: afton,ny
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| Posted: Fri Feb 22, 2013 1:36 pm Post subject: Re: Tailwheel upgrade |
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I take off and land my Firestar 90% from grass, never had a problem with the stock tailwheel,
Might not look like much but it's very high functioning
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