Jono
03-18-2014, 04:06 AM
Hopefully this post will help somebody else further down the track and will answer any questions or make their life just that little bit easier.
Background:
Basically my Dad was cool (some say crazy) enough to build a Kitfox Mk4 while I was growing up so that we could both enjoy flying around the sky. He is even kind enough to let me fly the Kitfox whenever I wish. What an awesome Dad!
6432
I did the daily inspection, pre-flighted the aircraft and everything appeared to be OK and as expected. I signed off the aircraft and Dad and I jumped in and started taxing towards the grass strip. As we taxied there was a loud bang, the attitude changed slightly and the aircraft came to a rather abrupt stop.
We shut down and got out to have a look at a suspected tail spring failure.... Yep... broken tail spring.... (otherwise minimal damage)
6434
After clearing the runway with rather red faces, and a high level of disappointment we jumped onto the internet and started to google “Kitfox tail spring failures”. It seemed to be a somewhat common topic...
So we immediately sent an email to John and Debra McBean (who were great to meet at Oshkosh last year) asking for some help in organizing replacement springs.
We got a response rocketing back overnight from John, who suggested that we replace the 2 leaf spring with the new and improved 3 leaf spring and we may also want to look at investing in a pneumatic tail wheel to assist with the shock absorption.
We ordered the new spring set straight away and Debra was fantastic in getting the replacement shipped to Australia, complete with tracking!.
About a week latter we had the new springs in hand:
A few observations:
They are the same width
Same thickness
Have a slightly more relaxed curve to them (no big deal.. just an observation)
The middle spring has a larger mounting hole for the tail-wheel (by design)
They are unpainted (which makes sense, what color is your aircraft?..)
The third spring added 400grams to the weight at the tail, leaving the C of G minimally impacted (well within limits)
OK.. so now the trial fit, we needed slightly longer bolts (2 x AN3-16 I think) and spacers for the rear of the springs and a longer bolt (1 x AN7-16 I think) to attach the Matco tail-wheel.
6435
While looking at the tail-wheel assembly at the kitchen table (where else would you do it?) I noticed that the teardrop rudder linkages were quite worn.... I almost had a heart attack!
6436
So we replaced the linkages, chains and inspected the whole assembly for wear (I recommend you do so too, if not already).
After lots of taxi testing, etc we were back in the air once again! I must say, that the support that we as Kitfox owners have from Kitfox LLC is fantastic and a huge "Thank You" must go out to John and Debra for continuing the Kitfox support! Without them, our only option for tail springs would have been to drive to Mt Beauty and steal “Rosslr's” springs!
For those of you wondering:
The tail spring failed at about 250hrs (600 landings), when the spring broke, the bottom of the rudder made slight contact with the runway (thankfully just cosmetic damage due to the grass runway)
Background:
Basically my Dad was cool (some say crazy) enough to build a Kitfox Mk4 while I was growing up so that we could both enjoy flying around the sky. He is even kind enough to let me fly the Kitfox whenever I wish. What an awesome Dad!
6432
I did the daily inspection, pre-flighted the aircraft and everything appeared to be OK and as expected. I signed off the aircraft and Dad and I jumped in and started taxing towards the grass strip. As we taxied there was a loud bang, the attitude changed slightly and the aircraft came to a rather abrupt stop.
We shut down and got out to have a look at a suspected tail spring failure.... Yep... broken tail spring.... (otherwise minimal damage)
6434
After clearing the runway with rather red faces, and a high level of disappointment we jumped onto the internet and started to google “Kitfox tail spring failures”. It seemed to be a somewhat common topic...
So we immediately sent an email to John and Debra McBean (who were great to meet at Oshkosh last year) asking for some help in organizing replacement springs.
We got a response rocketing back overnight from John, who suggested that we replace the 2 leaf spring with the new and improved 3 leaf spring and we may also want to look at investing in a pneumatic tail wheel to assist with the shock absorption.
We ordered the new spring set straight away and Debra was fantastic in getting the replacement shipped to Australia, complete with tracking!.
About a week latter we had the new springs in hand:
A few observations:
They are the same width
Same thickness
Have a slightly more relaxed curve to them (no big deal.. just an observation)
The middle spring has a larger mounting hole for the tail-wheel (by design)
They are unpainted (which makes sense, what color is your aircraft?..)
The third spring added 400grams to the weight at the tail, leaving the C of G minimally impacted (well within limits)
OK.. so now the trial fit, we needed slightly longer bolts (2 x AN3-16 I think) and spacers for the rear of the springs and a longer bolt (1 x AN7-16 I think) to attach the Matco tail-wheel.
6435
While looking at the tail-wheel assembly at the kitchen table (where else would you do it?) I noticed that the teardrop rudder linkages were quite worn.... I almost had a heart attack!
6436
So we replaced the linkages, chains and inspected the whole assembly for wear (I recommend you do so too, if not already).
After lots of taxi testing, etc we were back in the air once again! I must say, that the support that we as Kitfox owners have from Kitfox LLC is fantastic and a huge "Thank You" must go out to John and Debra for continuing the Kitfox support! Without them, our only option for tail springs would have been to drive to Mt Beauty and steal “Rosslr's” springs!
For those of you wondering:
The tail spring failed at about 250hrs (600 landings), when the spring broke, the bottom of the rudder made slight contact with the runway (thankfully just cosmetic damage due to the grass runway)