Fuse length and new gear

[wypaul 448]

Ok I have some more photos of the damage to the fuselage.

 

I wish I knew for sure but from what I know is that on landing as the plane was slowing down and then the ground loop.  I did bounce the plane a little on touch down so the question is was the gear damaged in the bounce or in the ground loop.  My thinking at this time is that the tailwheel released and caused the ground loops but I really have no idea.  I set the bakes so they were very hard to reach this time so I am fairly certain that I did not get on the brakes.

 

I have 800 hours in a Q-2 TD which is pretty twitchy on the runway, with no ground loops so I am baffled with the problems that the Avid is presenting.

Edited 1 Apr 2013 by Paul S

[wypaul 448]

I haven't quite figured out this new format and have trouble figuring out where to make the attachments yet so I will try this again.

Edited 7 Apr 2013 by Paul S

[1avidflyer 1983]

I guess if you strengthen the weakest link in the chain,  then you break the next weakest one.   My thoughts are this, if one was to somewhat infill the seat truss with metal, that would strengthen that.  Good plan even with the standard bungee gear.  I see where some have infilled the sides of the fusaloge as well.  I've done both of those on the Avid MK IV I'm rebuilding.  Wonder what is the next weak link.  Looking at the bent top crossbar on the cabane, I wonder if it had a verticle tube between the cross tube and the V if it would have held up.  Of course, the more tubes you get in there, the more weight and drag.  I'm thinking that some light gauge aluminum going from the flat fusaloge to the bottom of the V in front and back of the V with just the tabs sticking out would streamline things quite a bit.  (was looking at pics of a Champ yesterday, and it's got a V built into the fusaloge and it's all covered in fabric)  Question to others, has the Avid V been bent in any of the times that things got bent?  Do they even use the top cross tube?  Maybe it's built with larger/thicker tubing???  I don't know.  Good topic for discussion though.  Take care,  Jim Chuk

 

PS  just went back and re read your earlier post Paul where you mentioned the verticle tube between the crosstube and V.  Don't  know if I read that before and just forgot or what.....  Well my dad had alshiemers for about 5 years before he died so who knows.....  He was about 87 though when it started,  I'm only "only" 61

Edited 31 Mar 2013 by Jim Chuk

[6320012s 12]

Paul,

I  ground looped my KF 3 a couple times right out of the box.   The second time was on pavement and folded the landing gear.   We concluded the Scott tailwheel to be the culprit, but the brake geometry made it nearly impossible to recover once it started to go.  ie. hard rudder correction caused opposite brake action that was more powerful than the rudder input.  My fix was to replace the gear with aluminum spring gear, fix the dog on the tailwheel, and reconfigure the brake pedal geometry.  Since then, I have felt in full control, and my CFI agrees the set up is much better.  The spring gear is wider than the KF 3 gear and I think that helped a lot.    I also put on tubeless Nalco 21" tires that I could leave pretty soft.  With all those tweaks and some practice, I now feel very in control both on gravel and on pavement.   However, my pre-flight does include a tail wheel check to test the trip mechanism.

[6320012s 12]

I have thought that infilling the trusses with plywood would work equally as well as sheet metal, and wouldn't require fabric removal.  Haven't done it yet on mine, but as I get more adventurous, I probably should.

[6320012s 12]

Oops, correction, I have a Maul TW, and have been wanting to switch to a Scott.

[Av8r3400 1179]

Matco uses the same style control mechanism as the Scott, but costs a fraction of the price and weighs much less.

 

I would agree that the Maul tailwheel combined with poor brake design and insufficient rudder effectiveness has caused many, many groundloops of these planes.

 

I would highly recommend that any new Avid/Kitfox pilot, regardless of tailwheel experience, remove the unlocking cam from the Maul tailwheel until they have at least 100 hours and 300 landings in their plane.

Edited 1 Apr 2013 by Av8r3400

[wypaul 448]

I will take the release off of the tailwheel before I try this again. My first thought was to convert to the tri gear but don't really want to do that.

David I looked at the video of the Grove gear test and I am considering that route. What does it take to use the Matco wheels and brakes or are different wheels required for the swap?

I hate to give up on the spring gear but I really have all the experience I want repairing the fuselage. I will be doing some reinforcement of the fuselage while I have the fabric off for repairs.

I have some photos of KF brake setup with the MC mounted to the floor and different pedals. I would like to see what is working for others so I am not spending time reinventing.

[Logtrucker 44]

Paul, Sorry about your gl problems, just thought I might throw in my two bits worth. Be sure to check your tracking, No Tow In! The t.d.s like a slight tow out mutch better. Probably you've already considered this, anyway a reminder, for what it's worth. Logtrucker

[1avidflyer 1983]

The plywood is a good way to go if you want to add strength and don't have it all bent up already.  Avid required the plywood infill if you went to the wide bungee gear.  If you have it all uncovered anyway, the metal might be better.  Take care,  Jim Chuk

 

 

I have thought that infilling the trusses with plywood would work equally as well as sheet metal, and wouldn't require fabric removal.  Haven't done it yet on mine, but as I get more adventurous, I probably should.

[1avidflyer 1983]

I was out in the garage looking at my fusaloge for the MK IV again, and got to thinking that this whole set up would be a lot stronger if the center of the V was tied verticly to the seat truss as well.  Without that tie, a lot of inward pressure is applied to the front  landing gear attachment  in a hard bounce.   That of course is what would pull the sides in, just as it did.  I think if one built the V off of the seat truss with the right triangulation of tubing, it would be very strong.  Of course then it wouldn't be removeable.  A verticle tube between the cross tube and the V would definatly help.  One could then put a strap in front and back of that tube to connect to the seat truss.  There is a tube going forward from the front of the seat truss that you would have to work around, but it could be done in a number of ways.  I'll include a rough scetch I drew up to try to show what I mean.  I'm sure this would all be stronger as well if the seat truss was infilled as much as possible.  I keep wanting to go to this topic cause I don't want a bent up covered fusaloge at some point in the future.

I guess if you strengthen the weakest link in the chain,  then you break the next weakest one.   My thoughts are this, if one was to somewhat infill the seat truss with metal, that would strengthen that.  Good plan even with the standard bungee gear.  I see where some have infilled the sides of the fusaloge as well.  I've done both of those on the Avid MK IV I'm rebuilding.  Wonder what is the next weak link.  Looking at the bent top crossbar on the cabane, I wonder if it had a verticle tube between the cross tube and the V if it would have held up.  Of course, the more tubes you get in there, the more weight and drag.  I'm thinking that some light gauge aluminum going from the flat fusaloge to the bottom of the V in front and back of the V with just the tabs sticking out would streamline things quite a bit.  (was looking at pics of a Champ yesterday, and it's got a V built into the fusaloge and it's all covered in fabric)  Question to others, has the Avid V been bent in any of the times that things got bent?  Do they even use the top cross tube?  Maybe it's built with larger/thicker tubing???  I don't know.  Good topic for discussion though.  Take care,  Jim Chuk

 

PS  just went back and re read your earlier post Paul where you mentioned the verticle tube between the crosstube and V.  Don't  know if I read that before and just forgot or what.....  Well my dad had alshiemers for about 5 years before he died so who knows.....  He was about 87 though when it started,  I'm only "only" 61

 

[wypaul 448]

Jim I see what you are talking about. Maybe a plate coming down from the seat truss that could bolt to the cross member on the cabane. I am going to do some infilling of the seat truss and also in the small triangle on the bottom just ahead of the gear attachment point where mine bent and kinked.

Have you purchased springs for your gear yet? If so did you get the springs that were mentioned in the Yahoo Group file from McMaster-Carr. My gear came with a stronger yellow spring(Die springs are color coded) and I am thinking that it may be a little to much spring. I did find the red spring at a better price here:

http://www.springsfast.com/part_detail_die.php?part=3193

Also I talked to Mark at Highwing LLC about the added king post in the cabane that we have been talking about. He is going to talk to Lowell, his partner but thought that it would be a good idea.

I think that Joey remove his bush gear but I am not sure. Maybe he would comment about his experience.

We have hijacked this thread, maybe we need to start another thread so the subject can be search easier.

Edited 1 Apr 2013 by Paul S