KR> Re: Tri gear tail first on runway.
I don't have a dog in this fight, but that is the way I also understand the stall. Angle of attack is the angle of the chord relative to the wind, not a horizontal line. So if the plane is descending in still air, the angle of attack will be greater than the attitude of the wing chord. . List-Post: krnet@list.krnet.org Date: Wed, 6 Apr 2011 20:23:23 -0500 From: "Mark" Subject: RE: KR> Re: Tri gear tail first on runway. To: "'KRnet'" , Message-ID: Content-Type: text/plain; charset="iso-8859-1" The angle of attack is dependent on the 'relative wind' and has nothing to do with the wing chord reference to speed, attitude of the aircraft/airframe or anything else other than the relationship of the aerodynamic chord of the wing relative to the "relative wind". There are a number of publications, including FAA stuff, that explain the concepts (I bet Mark L can chime in here too) :) Mark W. N952MW
KR> RE: Wheel Pants Landing Lights
If you suspect the maintenance might be an issue, than maybe a simple circuit with a LED on the instrument panel might be interesting. Circuit can be designed to light up when a bulb is out and can be active even if the lights are not powered on (ie: day time) That might save some cycles on the switch/relays and bulbs, extending their life. total weight should be no more than the weight of a led, a resistor and a transistor. ""I fully expect the lights in the pants to be a maintenance "issue", but it is a checklist item that I am willing to deal with.""
KR> Wheel Pants Landing Lights
Is it customary to leave wheel pants on in the winter months on a KR? I really don't know, so I'm asking. Seems that at my airport wheel pants are removed on all aircraft in the winter. And I would imagine that the lights would go through abuse they were not designed for. Seems that every time I drop a flash light, the bulb is gone. But than again, I have absolutely no experience with such things, just thinking out loud. ""Hi Dave, The person, I'm getting my KR2 project from went the same route, though I would really like to hear everyones opinion on this""
KR> Exhaust headres
Among all the distractions, I hope no one minds that i get a bit of topic and start talking about aircraft conversions I was wondering why so far I did not see any headers on corvair engines. On cars, headers accounted for up to 5% increase in horse power. What is the reason why the same can not be true for aircraft conversions? I guess at cruise the exhaust gases are efficiently evacuated and maybe headers will not give much of an increase in hp. But still I think it would be a benefit for the weight at take-off and climb. And also would increase the smoothness of the engine. Looking at the exhaust examples, I wonder if the exhaust really is tuned for the engine, or can the back-pressure be smoothed out.
KR> Re: tubular wing tanks
in my experience PVC is not a good male mold. Hard to separate. Cardboard shipping tubes on the other hand are perfect. Once Composite sets, a few minute soak in a bath tub, and the tube separates and peals off. "Forgive me if this is an ignorant idea, but has anyone considered laying up fiberglass tube tanks using PVC pipe as a male mold? Edward Spyker"
KR> fuel burn vs Hp
You guys might be over thinking this. In theory that calculation is possible if. You have perfect carburation (but you don't) you have perfect timing (but you don't) Your manifolds are 100% efficient (but they aren't) your fuel burn is based on top output at stp (but it isn't, its an average) and so on. If we think about it, we can add at least 50 more things that will affect your fuel/hp ratio. but if your setup was perfect than 2gph for 100hp is closer.
KR> Latest intake manifold experiment
In my younger days we used to put aluminum window screening sandwiched between 2 carburetor spacers to help atomize fuel. Theory was that the screen creates micro vortexes and helps with a more even air/fuel mixture distribution to all cylinders. We didn't have a dino machine to test this out, but my guess would be that we gained at least 5hp. This might be worth looking into for the uneven burn problems.
KR> RE: KR nose wheel shimmy
Like you, I have my experience with cars. I would like to know how negative the caster angle was on the plane. Yes, unlike in cars where the caster angle is positive, and the more positive it is, the better stability, and wheel return. But its harder to turn the wheel. In the nose wheel of a plane, the caster angle is negative, very much like in a shoping cart. But similar principles apply. Stability should improve with a more negative angle, and wheel return to center should be better but it should be harder to turn. In a shopping cart, when the wheel doesn't have a full load, it will also shimmy. Im also curious if the weight of the plane in motion is evenly distributed to all wheels, or is the weight on the nose wheel light. and if the air pressure in the tire was adjusted to compensate for a lighter load. IMHO most common causes for a shimmy like that would be an over inflated tire, a tire out of round, or an unbalanced tire. Also there is a posibility that the wheel was modded in a way that the caster angle was decreased, (moved closer to 0) If everything checks out, Im betting on an over-inflated tire same can be observed in a car when the tires are over-inflated going over a bump, the tire will bounce, and steering wheel will oscilate. I do agree that the wheel pants could amplify the oscilation. In the past open wheel race cars suffered from catastrophic crashes due to aerodynamics on the open wheel. I really dont know anything about airplane landing gear, but am comparing the sympthoms to automotive tech. I do admit, no where on a car or a bike is the wheel caster negative so its hard to compare the two. "Maybe I should have emphasized caster angle a little more... caster angle (the angle from the vertical pivot point to the contact patch of the tire on the pavement, similar to the trail on a motorcycle) can improve the stability and natural tendency of the tire to track true. I agree with all of the points that Mark L has made, but the video I saw showed the shimmy continuing all the way down the runway... if the caster angle and balance had been properly done, the shimmy would tend to cancel out as the plane went down the runway. Granted, I know more about motorcycles and cars than I do about planes, but once the bird is on the ground, I would think similar rules would apply. Yes damping is important, but if the geometry of the set-up is off, it won't help the shimmy unless the gear is "locked in" (too stiff) which kind of defeats the purpose of a castering nose wheel doesn't it?"
KR> Battery crossover (isolator)
I think you might have misunderstood me. I was talking about a crossover, or more commonly known as an isolator. There wouldn't be any mods to the dashboard. All an isolator does is isolates the batteries, so they are not "bank" charged. Just do a search on a battery isolator, and you will get many hits. It connects to the alternator (+) and from there goes to the batteries. Here is a link to the first of many hits. But I'm sure you can find much cheaper sources http://www.newmarpower.com/Battery_Isolator_Integrators/Battery_Isolator_Integrators.html Also might look at the intergrator just below the isolator, its a different option, that does something similar. This was in response to your concern of one battery going dead, and dragging the other with it. "I'm not ready for a major panel redesign yet, probably never. With all the additions and changes over the years it could well do with a panel makeover"
KR> Back-up Battery
I'm not sure if this would work in a plane as a back-up. But in RVs and boats in order to use 2 different batteries for instance a car battery and a deep cycle battery, A simple cross-over circuit is used that can be purchased at any RV or marine store. The cross-over is pretty much just a high current rectifier bridge that allows current to travel only in one direction. "In designing my back-up system I took care to completely isolate both systems . . . except for the occasions when I might want to connect them . . . which would be to charge them concurrently, either in the hanger or in flight."
KR> Wide Band 02 Controller with Gauge
Not to confuse anyone, but This gauge seems to be pretty sweet too. http://www.holley.com/534-201.asp
KR> experimenter Polyisocyanurate Foam
You might want to double check the Tuff-R I think it has an aluminum laminate on both sides I'm not sure, but if thats true, the laminate IMHO makes the foam useless for construction. Also I'm not sure if the properties of the foam are with or with out the aluminum laminate. So if you peel the laminate away, the properties might go down the hill.