Shopping for a new tailwheel spring

[PapuaPilot]

I had the thick Grove aluminum spring and only used it during construction. I was super stiff. Now I have the T3 and love it.

FYI I wouldn't enlarge the TW tab holes until the original holes get elongated. They only need to hold the side load or shear load of the spring and the AN3 bolt is fine.

[airlina]

I had the thick Grove aluminum spring and only used it during construction. I was super stiff. Now I have the T3 and love it.

FYI I wouldn't enlarge the TW tab holes until the original holes get elongated. They only need to hold the side load or shear load of the spring and the AN3 bolt is fine.

Phil, I don't disagree with you much , but i do disagree that the AN 3 bolts are sufficient in this application. There were several failures back in the late 90's when I was building and many guys started drilling the holes larger for a AN 4 bolt which is what I did during my build. I also got rid of the tubing in the original design and made a solid aluminum bracket that wraps around my leaf spring. Even with all that one of my AN 4's sheared a few years back, so this is a known common failure point that should be checked closely on every preflight easy to miss the missing bolt and if you don't catch it you're probably in for mr. toads wild ride on your next flight. Also as Jeff mentioned the aluminum grove gear from our era (late 90's kits) are suspect (again several documented failures with rudder damage as the result and a big fix.) I ran mine for several years until a fly in when another Series 5 builder who had his fail , made me promise to replace mine, which I did with a 3 leaf steel spring that works fine.

[jiott]

My AN3 tailwheel clamp tab bolt sheared from side load. Replaced it with AN4.

[jrthomas]

I've been thinking about the Grove tailwheel spring for my model 4. It originally came with a 2 leaf but I replaced it with a 3 leaf during construction. After about 5 and a half years it seems to have sagged a little. Some years ago I had a tailspring break on a friends model 2 so I'm naturally a little gun shy. I tend to be a little on the tail heavy side so lighter is better. I use both paved and grass strips, nothing rough so the T3 is not needed. I know that the Grove that Kitfox sells is for models 5 through 7. Mangy Fox adapted one to his model 4 and seems to like it. I guess what I'm looking for is advise. Is this a good upgrade? Also what's involved in adapting the Grove? I have the Grove main gear with 22" Dessers.

[n85ae]

There have been several of the original Series 5 builders who broke their airplanes from those AN-3's breaking.
I guess it's open for debate as to "why" they broke, but nevertheless they did. The cost of AN-4's is miniscule, and
reaming the holes, and making new spacers is trivial ... So that's what I did.

Next step will be adding some weldment to reinforce the tabs which are also known to break off when you least
expect it ...

The original Grove Spring that Skystar provided I talked to Grove and their reply was fairly simple:

"The safest thing you can do is remove it."

Regards,
Jeff

I had the thick Grove aluminum spring and only used it during construction. I was super stiff. Now I have the T3 and love it.

FYI I wouldn't enlarge the TW tab holes until the original holes get elongated. They only need to hold the side load or shear load of the spring and the AN3 bolt is fine.

[Delta Whisky]

Phil, I don't disagree with you much , but i do disagree that the AN 3 bolts are sufficient in this application. There were several failures back in the late 90's when I was building and many guys started drilling the holes larger for a AN 4 bolt which is what I did during my build. I also got rid of the tubing in the original design and made a solid aluminum bracket that wraps around my leaf spring. Even with all that one of my AN 4's sheared a few years back, so this is a known common failure point that should be checked closely on every preflight easy to miss the missing bolt and if you don't catch it you're probably in for mr. toads wild ride on your next flight. Also as Jeff mentioned the aluminum grove gear from our era (late 90's kits) are suspect (again several documented failures with rudder damage as the result and a big fix.) I ran mine for several years until a fly in when another Series 5 builder who had his fail , made me promise to replace mine, which I did with a 3 leaf steel spring that works fine.

I see the fender washers under the front attach point. Done to change the angle of the trailing spring angle? To solve a problem I might have? Inquiring minds want to know.

[n85ae]

I believe Bruce welded a plate under the original tabs after having a weld breakage. So likely the washers are compensating
for the additional metal in the back to keep the Spring angle correct.

I'm sure he will post a reply.

Jeff

I see the fender washers under the front attach point. Done to change the angle of the trailing spring angle? To solve a problem I might have? Inquiring minds want to know.

[airlina]

I see the fender washers under the front attach point. Done to change the angle of the trailing spring angle? To solve a problem I might have? Inquiring minds want to know.

Darrel, Jeff hit the nail on the head with his response, after ski flying season ended last spring and I was removing my tailski, I found that one of the tailspring mounting plate tabs had cracked along the factory weld , so I fabricated a steel gusseted doubler to beef up this area (my era Series 5 did not have the beefed up version that I believe the factory is doing now) . I always thought this area of the Kitfox was a bit wimpy with all that goes on back there especially on unimproved runways and while skiing and I was proved right , even though it took 18 years . Hence the spacers are required to make up for the doubler thickness. As a side note i saw your great looking plane at Sentimental Journey -nice job, quality work and it really stood out in the parking row even though we were the minority among all the Pipers. (2nd photo is the original break and 1st photo shows the doubler ready for install- was a tough area to weld due to the restricted access and fabric repair was required after a bit of expected meltage.)

[Delta Whisky]

Thanks for the kind words on the plane Bruce. I tried to keep an eye out for you - hanging around your good looking plane maybe - but no joy. We'll have to keep an eye out for fly-ins somewhere between central PA and northern Virginia and plan an in-person meet up.