Good old number 29

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Everything posted by Good old number 29

  1. Good old number 29 added a post in a topic I can’t believe it’s not winter   

  2. Good old number 29 added a topic in Avid fox flyers pics and vids   

    I can’t believe it’s not winter
    I’ve been enjoying the last bit of winter, here in my neck of the woods. The snow will be too far gone, on my home strip, for skis, after this week. 

    I did find the limits of my Federal 1500 skis, a few days ago. Eighteen inches of rotten snow, loose, wet, granulated ice, under four or five inches of crust. Sorry, no pictures of that adventure. Yes, I did fly out of it, after getting unstuck for the sixth time. 
     
    Two lessons from that. One, hard crust in the morning can be a very soft mess in the afternoon. Two, skin those skis with plastic to widen them. I’ve thought about it since I got them, but never had a problem until now. It’s a good thing I didn’t find those limitations on a glacier, or in the mountains. 
     
    Misadventures aside, I’m enjoying the nice warm weather, and being careful where and when I land. 
     
     





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  3. Good old number 29 added a post in a topic Running lean   

    After pulling apart the top end and taking some careful measurements, it appears that the bore is well within spec, but the pistons are worn past maximum spec for piston to bore clearance. 
    The original pistons are stamped 71.92 mm (not the 7.93/7.94 red dot/green dot spec), but measured at 71.755mm. The bore measured at 71.99 mm, still slightly under the original 72 mm spec. That put the piston to bore clearance at .235 mm, which is more than the maximum allowable clearance of .2 mm, and well beyond the .07-.09 mm build spec.
    Ring end gap was at .65 mm, still less than the 1 mm max, which seems huge. The rings were a bit eaten up, with surface pitting particularly noticeable on the top rings of each piston. The exhaust ball joint had also broken apart, ending up in the muffler. Remember where it says to lube that with high-temp antiseize? Another good thing to remember. That allowed a minor exhaust leak at the y-pipe, which is likely to have contributed to burning out the rings.
    There is minor scoring in the cylinders, only below the exhaust ports, just enough to catch a fingernail. 
    I believe that the loosened tolerances of the well-worn engine helped to prevent a seizure during the high temp takeoff. Prior to my ownership, it had once been hot-seized on takeoff, caused by an improperly installed fan. The owner made the impossible turn back to landing. 
    All things considered, not bad for an engine that’s going on 39 years since manufacture, and 500 hours. 
    I’m tempted to hone the cylinders and just replace the pistons and rings, but that leaves me questioning the center crank bearings and big end rod bearings, which are still original. Even more to think about, since it is an early Provision 4 motor, with single ignition. 
    It sure has been a good engine. I have to say that the simple, lightweight engines, like this 503, have really been underrated. People laugh when they hear it has 50 horsepower, but lots of planes were built to fly with that much power, and lots of them are still around. There might be something to it. 
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  4. Good old number 29 added a post in a topic Tail ski   

    Good turning radius, especially in soft snow. I could turn sharper, but wouldn’t want to twist an axle. The lighter tail makes it easier to lift with the elevator, and swing around. Tracks straight with the tail down, with proper surfaces. 
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  5. Good old number 29 added a post in a topic Tail ski   

    That looks good. I was originally thinking of doing a penetration ski, but decided that it made more sense for me to use a straight tail ski, since I have straight skis in the front. I’m planning to make a set of penetration skis to go all the way around, in the long term. This tail ski was a kind of pilot project to test the structure and see how it worked. 
    After I decided on a straight ski, I was considering how to mount it, possibly using a Matco or Maule tailwheel assembly. I had some concerns about the pivot unlocking. Maybe unfounded, because a lot of guys run these, but imagine what would happen if it spun around. You’d want to be careful that there was enough ski in the back, behind the pivot point, that it could straighten itself out, and not just run backwards, and also that it wouldn’t dig in if it spun around. 
    So, I settled on using a fixed ski, bolted directly to the tail spring. I set it in glass, so the mount is formed to the spring, holding the ski perfectly straight. And, it works. It actually turns much tighter than it did with the wheel in back. The tail lifts easier, being over five pounds lighter, and it has a higher angle of attack, in a three point stance, since the ski is several inches shorter than the wheel. No cables or rigging, just one nut on the bolt that’s glassed into the ski, and off you go. 
    As an added bonus, I also found that the tailwheel springs had nearly worn through the holes on the rudder horn, as Alaskaflyer also recently saw on his Avid, so I get to fix that without the pain of finding it the hard way. 
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  6. Good old number 29 added a post in a topic Tail ski   

  7. Good old number 29 added a topic in Technical tasks   

    Tail ski
    Just tried out my prototype tail ski. I’m happy with it. After fifteen minutes of typing a detailed description on Facebook, the page reloaded and deleted everything. Here are some pics. I’ve identified improvements, but am only happy with the results. 2.25 pounds without paint, fiberglass over foam. Turns sharper than with the steerable tailwheel, but lighter rudder feel, and no loss of steerability or rudder authority. Solid success. 
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  8. Good old number 29 added a topic in Technical tasks   

    Tail ski
    Just tried out my prototype tail ski. I’m happy with it. After fifteen minutes of typing a detailed description on Facebook, the page reloaded and deleted everything. Here are some pics. I’ve identified improvements, but am only happy with the results. 2.25 pounds without paint, fiberglass over foam. Turns sharper than with the steerable tailwheel, but lighter rudder feel, and no loss of steerability or rudder authority. Solid success. 





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  9. Good old number 29 added a post in a topic Running lean   

    It’s about 450 lb. Those would be great options. I kind of like the idea of going to a four stroke. 
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  10. Good old number 29 added a topic in Rotax and other engines   

    Running lean
    It’s getting to be time to rebuild or replace the tired, old, original 503 in my Kitfox 1. I freshened it up with new crank end bearings, when I bought it, at 196 hours. As of today, it’s at 480 hours, so it’s really close to the recommended 300 hours for a complete crankshaft overhaul. We didn’t separate the crank and replace the center bearings or big end rod bearings, when we did the outers, so it definitely needs to have the whole thing done. 
    Aside from that, it has lost compression, due to a lean running event, this fall. I took a long cross-country trip to interior Alaska. I had the prop pitched for cruise, and jetted accordingly, but after an overnight in Talkeetna, I took off at -10°, saw over 1,200 on the EGT gauges, easing off the throttle to get cooler temps, but the damage was done. Since the EGT probes are calibrated at 70°F (a fact I had forgotten), that adds another 80° (the difference between 70° and -10°), meaning the temps were actually in excess of 1,300. Yikes! 
    Anyway, it was a great trip and I made it home safely, but the loss of compression is fairly obvious. The prop keeps turning the engine over for a couple revolutions when I shut it off. I had to pitch the prop down to get enough RPMs for takeoff, but the takeoff run increased from 250 feet to 500, due to the lack of power. A compression gauge has both cylinders around 91 psi, which I’d consider to be low for this engine, but I don’t know what it was, before. 
    After that incident, I pulled apart the top end and de-carboned the cylinders. No cylinder scuffing or melted pistons, so I put it back together. I might have honed the cylinders and replaced the rings, and possibly the pistons, but I know it’s time to do the crank, so I didn’t want to do the top end without taking care of the rest. 
    While I had the engine off the plane, I also checked the points and changed the gear oil in the B box. Timing was in the middle of spec, but .005” different between cylinders, so I opened the points back up to max advance, the same on both cylinders. The oil in the gear box did not have any metal in it, but was dark, which it had not been at any other time. Having considered this awhile, I concluded that it was most likely caused by blow-by past the pistons, pressurizing the crankcase and pushing carbon past the crank seal, into the gearbox. 
    So, like it or not, it looks like time to take care of the old girl. It is the original engine, ordered with the plane in late 1984. I do want to take care of it and keep it all together, but it is underpowered and a single ignition, so I’m considering an upgrade. Unfortunately, my pocketbook is also running lean, so options are very limited.
    My first choice might be an MZ202, with less weight and more power, but a new one, at ten grand, is out of the question. New 582 engines are apparently still available, but similarly expensive. I like the Yamaha Phazer conversion, which would require more work on my part, but could be done for less than a new 582, if I was good about it. I’m wary about purchasing a used engine from someone I don’t know, but a provision 8, dual ignition 503 or 582 would be an improvement, with the bigger crank bearing and dual ignition. Or a 670, for that matter. 
    For the cost, I might just rebuild the original motor and  run it, but it seems like a good time to upgrade. If anyone here has something available, that would be suitable, let me know. 
    And, as always, be careful about running too lean.

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  11. Good old number 29 added a topic in Avidfoxflyers General Hangar   

    Scrappy specs
    I loosely followed Mike Patey’s “Scrappy” build. He had some great concepts. Has anyone seen performance specs on it? I saw that it weighs a ton, 2,500 pounds, or so, and that it had 600 horsepower before he adds twin turbos, but does anyone have details on the real world performance, like takeoff and landing distance, or VS0 or VNO?
    I’d love to take it for a spin. It is rated for spins, right? Jokes aside, I’d be really interested to see and feel how it actually handles on the ground and in the air. I wonder if he saves any of his good ideas for another plane, or just crams them all into the one he’s working on at the time. Might as well try it all, then sort out which ideas work best in another application, later on. 
    I’d like to see some of those features, like the leading edge slats and suspension, incorporated into a lighter, simpler design. I’d guess we’ll see some of that in his new Draco project. 
    It has a heavier empty weight than a Helio Courier, and I’d assume the gross weight is higher, too. More horsepower. I wonder how Scrappy compares to other planes of similar weight or horsepower or dimensions. It’s kind of in a category of its own. Any word on performance specs?
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  12. Good old number 29 added a post in a topic Added 1 degree pitch to my prop   

    How does the new wing’s performance compare with the under camber wing? 89 mph is pretty good! The 503 in my model 1 drags it through the air at about 60 mph, straight and level, at about 5,700 rpms, or 90% power. That’s with a really draggy cabane gear and 25” Goodyears. No comparison to the Jabiru, I’m sure. Bob told me his model 4 cruised at 90 with the 670. He also said his model 1 flew slower, as in a lower approach speed or stall speed, and he preferred that plane. Maybe I missed a post, but how did the different wings affect performance on your plane? Are you happy with it, or do you consider switching back, for any reason?
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  13. Good old number 29 added a post in a topic Bringing a Kitfox 1 back to life   

    Will this rain ever stop?
    I flew for a couple hours this morning. It sure was nice. I should have taken pictures, but I kept the doors closed and just enjoyed the flight. I have a flight review due soon, so I went through a bunch of stalls, S turns, slow flight, and other maneuvers, maintaining steady altitude. The flight was followed with the hard slip and soft three point that my short field requires. The field has some bumps, so the landing isn’t always as soft as it was today. It’s always really satisfying to grease it in there like that. Last winter, I made some adjustment to my flaps. I had found that the plane would fly level, without stick pressure, with the flap lever pulled up about an inch. Typical thing that many Kitfox owners do to trim the plane’s pitch. I figured that was just wasting a few degrees of flap, and adjusted it to fly level with the flaps up all the way. That is, with the lever down as far as it will go, the plane is trimmed in flight. As a side note, I had first needed to adjust the angle of the horizontal stabilizer in order to be able to trim it and not need forward stick pressure. With the flap adjustment, I got it close, but need just a hair of back pressure now. 
    I’ve been debating whether to make that last bit of adjustment by moving the flaps back up slightly, decreasing the total down angle with full flaps, or by moving the front of the horizontal stabilizer back down. I did see a slightly lower stall speed after the flap adjustment. 
    After my morning flight, I decided to check the flap angle, along with the angles of the wings and horizontal stabilizer. With the plane sitting on 25” mains, on the relatively flat ground, I used the handy level feature of my iPhone to check the angles. I used a straightedge from leading edge to trailing edge of the wings, checking the angle at root and tip, as well as measuring the angle of the flat-bottomed flaperons while “flaps” were down, then up, and also checked the angle of the horizontal stabilizer, and the floor, which is used to determine level for weight and balance. 
    With the flaps down, and both flaperons at the same angle, flaps were at 26°. Note that 26° is not the flap angle, in regard to wings or angle of incidence, as the plane had all three wheels on the ground. 
    With flaps up, both sides showed 9°. This is a difference of 17°. Full flaps = 17°. I wonder how much less flap angle there was before my last adjustment. Maybe 2°-3°? 20% less?

    Full flaperon deflection netted a range of 8° to 50°, with the flaps down. That’s 42° total up to down on flaperons. That 8° is only 1° more than the wingtips, or 6° up at the root. I hadn’t considered previously, that the flaperons move up relatively less at the wingtip, due to wing twist. It has 18° up, and 24° down. It should be the other way around. Everything about it is in favor of adverse yaw.
    The wingtips showed the same 9° as the flaperons, flapped up. Both wings had the same angles for root and tip. The angle at the last rib was the same as the droop tip.

    Wing roots showed 14°. That’s 5° of twist, root to tip. The floor was the same angle, 14°.
    The horizontal stabilizer was at 11°.
    While I concluded several things from this, I’d love to hear any input you might have. 
    First, let’s put in perspective. Obviously, it won’t fly a steady altitude with the floor level. The root would have zero AOA, and wingtips would be minus 5°. Flaperons would likewise be reflexed to -5°, while the horizontal stabilizer would be at -3°. I’ve often thought it could use a bit more angle of incidence. But, the floor is just a reference, anyway. A flat plane, if you will, that’s easy to level.
    Ignoring all that, I think I ought to give it another 1° to 3° of flap, and put the horizontal back to its original position. Doing that would put the flaps, while retracted, at approximately the same angle as the bottom of the wing, while also increasing the total angle of the flaps, extended. That would be the same angle as the middle of the wing, rather than the tip.
    I believe that this would make it more efficient inflight, as the flaperons, wings, horizontal, and elevator would not be fighting each other as much.
    My wife shoots video of most of my takeoffs and landings, here at the house. Today’s video of the landing showed that the tailwheel stayed off the ground while I had the stick back a good bit. I don’t believe that I was hard on the brakes, if at all. My usual routine is to keep the tail up, after I touch down, so the tailwheel isn’t eating the bumps, and let it roll out. Balance would have been neutral or slightly aft, with just a few gallons in the panel tank, and wing tanks empty. 
    https://youtu.be/p_64N6ywJDo
    On the negative side, it would have about zero up aileron, at least at the wingtip, with flaps deflected. I’m not sure if it could have much more adverse yaw than it currently does, but the rudder works just fine. One more thing, that might become an issue, if it’s not already, is that the flaps might not fold up flat enough when the wings are folded back. I had considered that that was the reason for that geometry, in the first place. If I ever need another project, I could convert to differential control, but I’m not planning to do that, at this point in time. I like the ease of folding the wings back, without disconnecting anything, even if I hardly do it anymore  
    I wouldn’t think there’s any benefit to taking the flaps back up. The ailerons don’t go up any further, at least, not if it’s trimmed to fly without stick pressure. I don’t have a stopper for the flap lever. It stops against the torque tube for the sticks. I’ve read the old concerns about control reversal and the need to limit flap travel, but never experienced anything like it, with about 275 hours and lots of full flap landings. Maybe that was first flight nervousness by those unfamiliar with the amount of adverse yaw, and they mistook the effect. 
    Here are the stats, simplified, as with the floor leveled:
    Angle of incidence, wings, average: -2.5°
    Range of motion, flaps: 17°
    Range of motion, ailerons: -18°/+24°; 42° total
    Angle of incidence, stabilizer: -3°
    Is it ever going to stop raining? Look what it’s done to me. I hope you’re all enjoying your Kitfox, whether working on it, flying it, or just considering its different angles.
     
    Matt


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  14. Good old number 29 added a post in a topic lost another one   

    Sorry to hear that. I called and talked to him just a couple weeks ago. He wasn’t feeling too good then, but I didn’t expect this. Rest in peace, Bob. 
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  15. Good old number 29 added a topic in Close Call's and dumb stunts   

    That sinking feeling
    A bit close, but got safely back on the ground. This one falls in the category of lots of little things that added up to a few tense moments. First, was the need to go somewhere. I have a cabin arranged for a couple days after my upcoming wedding. This cabin is accessible only by boat or aircraft. I loaded up the plane to haul the a few things ahead of time, since it would be crowded and heavy to try to squeeze the stuff in there with my bride. I wasn’t ditching the wedding to go hunting. It was just to haul stuff. Since I’m still waiting for new Powerfin blades, I have the old fixed GSC prop on the plane. It was relatively warm out, this evening, when the wind was letting down and the tide was right. I wanted to have plenty of fuel, since the forecast was for a headwind both ways, so I had an extra seven gallons more than what I might have needed. I took off from a good grass strip with tall trees at the end. I never have trouble with that strip, so I eased on the power as it rolled along, no flaps, with a wing low in the crosswind. I was halfway down the strip when I eased it off the ground. Climbing slowly above treetop level, I pushed the throttle all the way in, only to hear one cylinder cut out and see the EGT on number one cylinder dip to 700. That sinking feeling. At that point, it looked very unlikely to get the plane back on the runway before the trees. Pulling the power back a bit, the engine picked back up and I safely cleared the treetops. Playing with the throttle revealed that I could safely run partial power, but it bogged out at full throttle. It was climbing so slowly.  I gained altitude to turn back toward the strip. Then came the smoke. That made the turn back a little more urgent. I opened the door, to get some clean air, and turned it around pretty quickly, landing downwind. I landed, thanking God it all ended well. Nothing obviously wrong, initially. A little fiddling revealed that the problem was a sunken carb float. Those were new a couple years ago, when I got the plane going. It seems that I threw out the old floats, which were the older style, probably thinking that it would be better not to try to reuse them. Thoroughly disgusted with the Bing/Rotax famous sinking floats, I ordered a set of the Marvel-Schebler floats. The fast shipping was more than the pricey floats, themselves, ought to be. While I could complain about all that, it’s a pretty good deal when I consider the alternatives. I do hope they arrive in time. I recommend changing your floats, given the well-documented history of these floats failing and sinking, and the risk of power failure or fire when they do sink. Thank God it worked out. All the little things made it a closer call than it should have been. Extra fuel, lesser prop, bigger tires, more drag from the big can of bear spray and electric fence stakes on the jury struts, the overflowing fuel hitting the exhaust, the warm weather, slow takeoff with a crosswind. Don’t take chances with carb floats that are known to fail regularly. I got about 250 hours in 2.5 years, with these ones, but it’s probably better just to not trust them at all, and find a good alternative. 

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  16. Good old number 29 added a post in a topic Powerfin blades   

    I got in touch with Jason, at Powerfin. A new set of 68” F blades will be heading my way, soon. He’s always been good to work with. Can’t wait to try them out. The biggest B blades were 66”, which is what I had. The bigger blades might still work for me if I ever upgrade to the Phazer motor. 
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  17. Good old number 29 added a topic in For Sale and wanted, you got it, I want it   

    Powerfin blades
    I’m looking for a set of three 66 or 68 inch Powerfin B blades. I have a hub. Just looking for the blades, if anyone has some available.
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  18. Good old number 29 added a post in a topic Thinking hydrosorbs would have been a good idea   

    It’s a beautiful day here. -2°F this morning. 




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  19. Good old number 29 added a post in a topic Thinking hydrosorbs would have been a good idea   

    Okay, here’s video of the landing. Look at how fast it drops when I clear the trees and cut the throttle. This is a fun strip. 
    https://youtu.be/KbT_SPXrQtQ
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  20. Good old number 29 added a topic in Avid fox flyers pics and vids   

  21. Good old number 29 added a topic in Avid fox flyers pics and vids   

    Kasilof River ski flying
    Here’s a great iPhone video of flying past the office at work. It was a beautiful day. Lots of good snow cover. It was a great day to get out and enjoy the great late-winter ski conditions. 
     
     
     
    https://youtu.be/ZRSwizHbVls
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  22. Good old number 29 added a post in a topic Snow landings   

    Here is a good video of the Kitfox on straight skis in the muskeg. 
    https://youtu.be/HCBFau3edCE
     
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  23. Good old number 29 added a post in a topic Bringing a Kitfox 1 back to life   

    I finally got my Federal 1500 skis rigged. It has been incredible ski flying around here, lately. 





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  24. Good old number 29 added a post in a topic Getting started in Indiana   

    Hi,
    Good to have you on here. There are a lot of knowledgable people here on this forum, and a few that are just plane nuts.
    It looks like a good project you have there. People here are awesome about helping out in all kinds of ways. Parts, information, and lots of good advice. 
    Post some pictures for us to ogle, if you don't mind. Many of us have been through all the stages of building, and still love to see the process and your progress. 
    Welcome.
    Matt
     
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  25. Good old number 29 added a post in a topic 25 mile radius   

    No longer constrained to the 25 mile radius, but  I did take all these pictures within 25 miles of the airport. Nice day for flying. 








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