Allen Sutphin

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Everything posted by Allen Sutphin



  1. Allen Sutphin added a post in a topic Hirth 3202   

    The cylinder wall and the piston are supposed to expand and shrink at the same rate, but that would be hard to prove. Supposed to be seizure resistant but any will seize if allowed to operate outside of its limits. The biggest issue will be to reverse the fan so it will be pulling fresh air from the front to the rear instead of trying to shove it forward. It is one of the low RPM/high torque engines I was mentioning. So we'll see if it does the job. Evidently a model 2 flew well with a 503 and this 3202 is a little more energetic than the 503 at a lower RPM.
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  2. Allen Sutphin added a post in a topic Controls   

    I know the correct method. That question was asked to a group at a meeting one time and you wouldn't believe the number of crazy answers. The whole discussion was about stall/spin accidents.  I found it interesting that in most stall/spin crashes the engine was running normal, and the aircraft was in some type of turn when it went into a spin.
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  3. Allen Sutphin added a topic in Avidfoxflyers General Hangar   

    Controls
    Simple question for the simple pilot. What makes an airplane turn?  Rudder, aileron, elevator, bank, etc,?
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    • 788 views


  4. Allen Sutphin added a post in a topic Super Skyraider for sale   

    I hunted for one for a year before I bought my Fox. Good deal!  New Ridgerunner kit (same kit, almost) is about double that.
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  5. Allen Sutphin added a post in a topic Issues flying behind a 2-stroke   

    I pay close attention to power and torque curves. I find them interesting when comparing engines. I find that the 65 hp of a 582 is mainly for take off RPM and after that drops off rather quick. A few low RPM 2 strokes maintain a flat power and torque band for a thousand RPM's below take off power allowing low cruise RPM's which is less fuel, less wear, less heat, which relates to reliability. Horsepower sells engines, torque turns props. Yea, I know the relationship between horsepower and torque, but sometimes we are mislead by factory horsepower claims into thinking that's all there is to it. If we took a hard look at the curves, you might find we are flying along at very low horsepower and doing just fine. Truth is that the STOL ability of an Avid/Fox is what brought us here to start with, and nobody dislikes a scary short roll and a nosebleeding climb capable aircraft if one chooses to do it. If we did, we'd all be flying C-150's or Taylorcrafts. Both good aircraft for their purpose, but lackluster performance. My dream aircraft is a Super Cub but I'll never afford to own one. So I got the next best thing (my opinion). And I can fly on lunch money! But then, some could fly a C-130 on their lunch money! (big eaters) LOL!
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  6. Allen Sutphin added a post in a topic Issues flying behind a 2-stroke   

    My Hirth 3202 does have a ditigal chip for limited spark advance. It is part of the PVL ignition. How good it does remains to be seen. I don't think its that much of a spread but does advance the timing based on RPM. I do know the reed valve system does idle smoother and throttle advances are smoother.  But they are another point of failure.
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  7. Allen Sutphin added a post in a topic Issues flying behind a 2-stroke   

    In my experience on GA engines, they don't have the EGT problems that a two stroke has. The biggest issue on GA engines is shock cooling, when pilots "cut and drop" so to speak.  Flying along at 7K and then throttle back out of the green and glide down to pattern altitude is extremely hard on the front two cylinders. First sign of damage is warped exhaust valve stems. On the 0-200 it also cracks the heads out from the spark plug seat. Rental aircraft usually have at least the front left cyl replaced a couple of times before TBO.  I've replaced several cylinders due to this and its always the front left one. Students are pretty hard on aircraft, private owners, not so much, once they understand what is causing it. And it comes out of their pocket. GA engines have issues just like 2 strokes, mostly due to improper operation.  Engines don't fail, they are murdered.
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  8. Allen Sutphin added a post in a topic Issues flying behind a 2-stroke   

    I had to read it several times but it finally sunk in, I think.  I wonder if my reed valve engine (3202) has the same principals applied? Probably does since they are on the intake side.
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  9. Allen Sutphin added a post in a topic Covering butt rib   

    Just glue it to the top and bottom of the rib. No flight loads involved, no stress, just mainly cosmetic.
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  10. Allen Sutphin added a post in a topic Wind   

    I think I'll leave that type of wind to you pro's. Around here in these ridges in a 25 kt wind, we won't even open the hangar door. Since my valley is approx. 300-500' wide in the narrow part, the venturi effect takes place and the wind speeds up quite a bit, throw in a 90 deg valley on one side and you have a nice side gust with no room to rock and roll. Plus a one way strip and always a tailwind. Call me a wuss or whatever, my days of that are long gone. I use the tissue test, drop a tissue and if it lands on your feet, OK.  My max is 0 gusting to one or maybe two. An old instructor use to say if the wind was more than 50% of your stall speed, it was risky.
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  11. Allen Sutphin added a post in a topic Wind   

    Flying around here anymore in mid day is a "high fiber diet".  Your rear end munches on the seat cushion from take off till landing. I think I'll start buying seat cushions by the dozen. I generally lose one every flight.
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  12. Allen Sutphin added a topic in Close Call's and dumb stunts   

    Wind
    Just curious, what is the highest wind you have flown in?  I have been turned up 90 deg before in this crack (opps, valley) I fly out of and was curious if I am the only one who  is a  tad gunshy of gusty winds. And I'll be honest about it, I "Don't like it".
    • 26 replies
    • 4,307 views


  13. Allen Sutphin added a post in a topic CONTRIBUTIONS TO KEEP SITE GOING   

    Old school, too! Check in snail mail!
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  14. Allen Sutphin added a post in a topic Vertical rudder tube issue   

    The visible rust on the bottom of the rudder vertical tube would be something to look at a little more closely. It could cause problems down the road. It might be just external or could be also internal, which isn't good. A common problem on tail draggers, especially on ones tied outside or in open hangars. Maybe a little snake oil in the tube might extend its life. I understand the no. 1 snake oil salesman is on here. Now is the time to inspect it. If you see the oil leaching thru the fabric later on then you would know there is a problem. But I am a little picky ( some use other words) when it comes to rust and tubing.
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  15. Allen Sutphin added a post in a topic Vertical rudder tube issue   

    That is a more logical reason for the problem. I didn't think fabric tension would bend the tail post alone. Might be a good thing to enforce on mine before I cover it. I have a habit of bumping the tail wheel first on landing, anyway.
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  16. Allen Sutphin added a post in a topic Filtered gas Funnel   

    Slick!  Cheaper than a Mister Funnel.
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  17. Allen Sutphin added a post in a topic Vertical rudder tube issue   

    I can't imagine fabric tension bending the rudder post. Not 1.8 or 2.7 oz fabric. I have seen 3.8 oz bend some wood structure but not a steel tube.  You could replace that piece of fabric with a panel. Would not affect anything. I would be curious to know why that piece of fabric keeps releasing tension. Possible fabric drumming, not to full tension (350 deg), or something evil.
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  18. Allen Sutphin added a post in a topic 582 Crankshaft Rebuild?   

    I think Steve Batty in Glendale, Az. does. WWW.airscrew performance.com
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  19. Allen Sutphin added a post in a topic E-Tec or Polaris 800 conversions   

    I've got a cog belt redrive left off my Hirth.
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  20. Allen Sutphin added a post in a topic Another Flapperon Failure   

    One thing most miss when they have a ground loop, even a minor one where the wing touches the ground without visual damage, is they need to replace the wing pins and bolts, plus they need to replace that rod bearing if it happens to be on the contact wing. Even hitting that wing on a hangar door or some other object, given the leverage from the wingtip, puts a lot of stress on fittings. Most look at a scuffed wingtip and say "man, I was lucky" and continue on without any thought to stress. In most incidents we are at fault instead of a rod bearing or part. And it could have started many flight hours before and we never give it a thought. Most are unaware of what they can't or don't see. How many replace that rod end every 2, 4, 5 years or so. Or is it the original from when it was built?  We have a habit of not putting the odds in our favor. Alright, I'll shut up now. I guess I am just tired of people putting blame where it shouldn't be.
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  21. Allen Sutphin added a post in a topic Another Flapperon Failure   

    I don't think its panic time just quite yet. 2 or 3 cases in a thousand aircraft with a few thousand hours under its belt isn't a disaster. Of course, it probably was to the two that it happened to. Situations like this can destroy an aircraft's reputation in a second. It is happening now with the QCU challenger aircraft. 4000 aircraft and 7 or 8 had wings fold in flight. Turns out that most ended up being owner/ builder error. But the wing fold issue stuck like glue. And earned it a damaging reputation. In most cases, its very hard to determine the what and why of how it happened. Builder error, bad design, defective part. incorrect assembly, we might never know but rod ends are used in almost every aircraft without issue or concern. Inspect them, of course, maybe even modify the setup if its a major worry. but word spreads fast in this internet world and what was once a good solid aircraft is now a flying death trap because of 2 or 3 cases. Tube failure due to corrosion has been around since there were tube aircraft and will continue. That's why we have conditional inspections every year, but a lot of them are pencil inspections which hurts us all. This type of group is great for info, but for the lurker who is thinking about buying an Avid/Fox, it can be very negative. I suggest we tread lightly till we know more, if we ever do.
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  22. Allen Sutphin added a post in a topic Another Flapperon Failure   

    Good AN fittings do have rolled threads, but they are not cheap. The cheaper one probably have cut threads. As much as 10 bucks difference in price apiece. The nose gear links take a beating most of the time so they are subject to high stress. Even though I've never seen one break. The aileron bearing should not be under that much stress, installed correctly under normal flight loads. I stand by the fact that something else is going on in this situation. Good rod ends do not break in normal use. In a kitfox or avid, I can't see how one could put enough pressure on the controls to snap a rod end or even fracture it. Unless it was a cheap knockoff, and they do exist. I am running across a few fittings made in Mexico that will not seal because the threads are not centered. Forged parts are a big thing in comm. aircraft and sometimes we use a few of the same parts. And john doe homebuilder out there is completely unaware. My story and sticking to it! But I have been wrong before, ask my wife.
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  23. Allen Sutphin added a post in a topic Operation Cannibal Fox   

    A model 1 beating a 5 with a 912 is possible and very likely with just a 582, at least as far as takeoff and landing. Top speed, well a model 1 is the wrong airframe. And for the STOL competition aircraft, top speed isn't great.  Very few STOL aircraft, if any, will make much over 100, maybe 115. But I find it ironic just what some call STOL aircraft or STOL fields. To this hillbilly, a 1000' strip is NOT a STOL strip. 500' or less is what I call short.  If it has a big "H" in the middle then its a short field.
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  24. Allen Sutphin added a post in a topic Operation Cannibal Fox   

    A kitfox model 1 with 150-200 horsepower!!!! Good grief, Charlie Brown. I think they call that an engine with wings and a seat.
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  25. Allen Sutphin added a post in a topic Another Flapperon Failure   

    I don't think Paul Harvey has spoke just yet. I'd say there is more to the rest of the story that hasn't been told. I've seen these wear out, rust up, and freeze, but never seen one broke like that in normal flight loads.
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