Todd Peterson
11-25-2007, 02:53 PM
I just returned from another trip to the Utah backcountry . I must say these repeated trips into the backcountry for the testing of the new Katmai is tough work, and a lesser man would be ready to just stay home and watch TV. I'm tough though, and you know me......work comes first.
I visited fourteen backcountry strips my first day in Utah. I took video of most of these, so they will be posted on our web site in the upcoming weeks. The strips ranged from Mexcian Mountain to Dirty Devil to lesser known strips like Nokai Dome. Some of the strips could be handled safely by a stock 260SE, others just beat the crap out of the Katmai with the new 29 inch tundra tires.
During the trip I continued to ponder some basic truths which is one of the reasons I take the Katmai into some really nasty places. I can then pass these along to my friends.
The first truth is the only thing that limits the Katmai on where it can go are the tires. As most of you know, I recently switched from the flexible sidewall 29 inch Bushwheels to a 29 inch more conventional tire with a rigid sidewall. The new tires wear much better on pavement and are much less expensive, they also handle cross winds better as the tire doesn't flex like the Bushwheels. The down side is they do not handle the really rough terrain like the Bushwheels. The Bushwheels are so flexible they simply contour themselves around the rock, lump of dirt, etc., and this really dampens out the shock transmitted to the airframe. The 29 inch conventional tire, even at a lower pressure, is still pretty rigid by comparison. This in turn transmits more of the shock to the airframe. The new tires worked fine on 90% of the strips, but for the other 10% I wanted the old Bushwheels back. I seriously doubt most owners will be visiting the worst 10% of these strips, so it may not be a factor. I also quickly came up with a Peterson rule: If the strip is so rough it knocks the glove box door open and dumps all the contents onto the floor, it is probably too rough for the tires you are currently using. This happened to me twice during the first day. The second day we just didn't go back to those strips. I have video of one of these strips, and you will be able to see exactly what I am talking about.
The next fundamental truth I pondered is in some places the terrain is so bad that the only decent place to land is the strip itself. While the terrain is bad in Idaho, at least you at times have the ability to land in the tree tops. In Utah there's nothing but cliff walls and rock. In studying this and wanting to maximize safety, I altered my approach pattern to one that kept me very close to the strip. Many of these strips are normally approached from a couple of miles down canyon. The approach consists of overflying the strip to check it out, climbing up over the canyon walls, flying down the canyon a mile or two, reversing course, and then dropping down in the canyon for a more-or-less straight-in approach. Of course, if you encounter an engine problem while in the bottom of the canyon you are going to have a bad day. As you will see in the video, I flew over the strip downwind to check it out at about 100 feet. At the end of the strip I did a 90 degree turn followed by a 270 degree turn the opposite direction. This put me on short final for the strip usually no more than a couple of thousand feet from the threshold. Even in the narrowest canyons the Katmai performed this maneuver safely every time, and it allowed me to stay close enough to the strip for a quick landing if a problem developed. As most of you know I am constantly looking for the safest way to get the job done, and I really liked this approach. This is no place for a novice, however. There's nothing like maneuvering safely in a tight canyon to a landing. The maneuvering ability and safety of the Katmai at slow speeds are truly unbelievable.
The other observation that I made is the 86 inch propeller tends to pick up some wear over the outer couple of inches of the propeller blades. The 82 inch propeller I originally used on this airplane had absolutely no wear at the tips after 80 hours of flying, most of which was in the backcountry. The longer 86 inch propeller tends to pick up more garbage from the ground, and I am constantly replacing the outer couple of inches of leading edge prop guard tape. I am going to look into this further in the upcoming months, but as of now I am beginning to think the 82 inch prop might be better for most because of the reduced wear and maintenance. A little thrust will be lost, but I don't think that is going to matter much with the IO-550 engine.
In closing, I am sending some pictures of the last strip I visited at the end of the second day. It is Mexican Mountain, and the surrounding country is absolutely beautiful. The length of the strip is about 1,300 feet, it is soft, very narrow in spots, and has a field elevation over 4,000 feet so the DA's can be high. The west end has a fifteen foot high obstacle right at the end of the strip which effectively cuts the strip length from that direction to around 900 feet. Like most of the strips I visited, you do not want to land either short or long. The King Katmai used about one third of the strip for landing and take off, effectively providing me with a 200% safety factor.
Within easy walking distance are petroglyphs from the ancient Indians who inhabited this region. If memory serves me correctly, they are over 1,000 years old. We also visited another strip, that after some hiking, allowed us to view some ancient Indian cliff dwellings. Oh man, was that cool! More on this later.
I visited fourteen backcountry strips my first day in Utah. I took video of most of these, so they will be posted on our web site in the upcoming weeks. The strips ranged from Mexcian Mountain to Dirty Devil to lesser known strips like Nokai Dome. Some of the strips could be handled safely by a stock 260SE, others just beat the crap out of the Katmai with the new 29 inch tundra tires.
During the trip I continued to ponder some basic truths which is one of the reasons I take the Katmai into some really nasty places. I can then pass these along to my friends.
The first truth is the only thing that limits the Katmai on where it can go are the tires. As most of you know, I recently switched from the flexible sidewall 29 inch Bushwheels to a 29 inch more conventional tire with a rigid sidewall. The new tires wear much better on pavement and are much less expensive, they also handle cross winds better as the tire doesn't flex like the Bushwheels. The down side is they do not handle the really rough terrain like the Bushwheels. The Bushwheels are so flexible they simply contour themselves around the rock, lump of dirt, etc., and this really dampens out the shock transmitted to the airframe. The 29 inch conventional tire, even at a lower pressure, is still pretty rigid by comparison. This in turn transmits more of the shock to the airframe. The new tires worked fine on 90% of the strips, but for the other 10% I wanted the old Bushwheels back. I seriously doubt most owners will be visiting the worst 10% of these strips, so it may not be a factor. I also quickly came up with a Peterson rule: If the strip is so rough it knocks the glove box door open and dumps all the contents onto the floor, it is probably too rough for the tires you are currently using. This happened to me twice during the first day. The second day we just didn't go back to those strips. I have video of one of these strips, and you will be able to see exactly what I am talking about.
The next fundamental truth I pondered is in some places the terrain is so bad that the only decent place to land is the strip itself. While the terrain is bad in Idaho, at least you at times have the ability to land in the tree tops. In Utah there's nothing but cliff walls and rock. In studying this and wanting to maximize safety, I altered my approach pattern to one that kept me very close to the strip. Many of these strips are normally approached from a couple of miles down canyon. The approach consists of overflying the strip to check it out, climbing up over the canyon walls, flying down the canyon a mile or two, reversing course, and then dropping down in the canyon for a more-or-less straight-in approach. Of course, if you encounter an engine problem while in the bottom of the canyon you are going to have a bad day. As you will see in the video, I flew over the strip downwind to check it out at about 100 feet. At the end of the strip I did a 90 degree turn followed by a 270 degree turn the opposite direction. This put me on short final for the strip usually no more than a couple of thousand feet from the threshold. Even in the narrowest canyons the Katmai performed this maneuver safely every time, and it allowed me to stay close enough to the strip for a quick landing if a problem developed. As most of you know I am constantly looking for the safest way to get the job done, and I really liked this approach. This is no place for a novice, however. There's nothing like maneuvering safely in a tight canyon to a landing. The maneuvering ability and safety of the Katmai at slow speeds are truly unbelievable.
The other observation that I made is the 86 inch propeller tends to pick up some wear over the outer couple of inches of the propeller blades. The 82 inch propeller I originally used on this airplane had absolutely no wear at the tips after 80 hours of flying, most of which was in the backcountry. The longer 86 inch propeller tends to pick up more garbage from the ground, and I am constantly replacing the outer couple of inches of leading edge prop guard tape. I am going to look into this further in the upcoming months, but as of now I am beginning to think the 82 inch prop might be better for most because of the reduced wear and maintenance. A little thrust will be lost, but I don't think that is going to matter much with the IO-550 engine.
In closing, I am sending some pictures of the last strip I visited at the end of the second day. It is Mexican Mountain, and the surrounding country is absolutely beautiful. The length of the strip is about 1,300 feet, it is soft, very narrow in spots, and has a field elevation over 4,000 feet so the DA's can be high. The west end has a fifteen foot high obstacle right at the end of the strip which effectively cuts the strip length from that direction to around 900 feet. Like most of the strips I visited, you do not want to land either short or long. The King Katmai used about one third of the strip for landing and take off, effectively providing me with a 200% safety factor.
Within easy walking distance are petroglyphs from the ancient Indians who inhabited this region. If memory serves me correctly, they are over 1,000 years old. We also visited another strip, that after some hiking, allowed us to view some ancient Indian cliff dwellings. Oh man, was that cool! More on this later.