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Activity Stream



  1. akflyer added a post in a topic Kitfox 4 Mixer   






    speaking of stealing intellectual property yada yada, was the fist kitfox now an exact clone of the Avid

    I got the same kind of feed back when I posted up the construction manual, but oh well.. I would call the manuals more of a guide line than a construction manual anyway as soo much is left up to the builder to figure out..



    oh yeah, luv ya too Larry


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  2. akflyer added a post in a topic Avid Catalina   


    Hey Tom,

    The Amphib project is on hold right now, Bob is working on the kitfox III.. I think it is up to silver now and may even have a top coat on it by now.


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  3. Garyh added a post in a topic Kitfox 4 Mixer   

    Thankyou Fatbastard builder kitfox flyer you sound like a descent bloke. Looks like theres no KF/ love out there, any how i have worked out the geometry
    now so all good. Once again thanks for your honest thoughts. Cheers buddy.
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  4. popslick added a post in a topic Avid Catalina   

    Well Hell, I guess I will just have to go up there and check it out in person!
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  5. flattie45 added a post in a topic Looking into VG's   

    First off, let me say that I have no experience with VGs (sorry!) I read an article about a fellow who installed VGs on the bottom side of the wing to eliminate some of the drag associated with the airfoil used on the Avid Flyer. He was in contact with Harry Riblett, who helped with the proper placement. Apparently at cruise speed an area of turbulent air builds underneath the wing, and the VGs help to break it up.
    This was sometime in the 90's, and he didn't do a whole lot of pre and post testing, but he figured he gained at least 5 mph, maybe more. I'm not sure if or how it affected slow flight characteristics. He called them more of a "question mark generator" than a vortex generator, since it looked quite odd.
    I think I still have the article on my home computer. I'll be home next week and post it when able.
    I know you are looking for more slow flight/control authority, but I always thought that it would be interesting to try.
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  6. napierm added a post in a topic True HAC carbs   

    Tom Olenik worked with Rotax and had the HAC dialed in only to have Rotax quit selling them.

    The Hacman works pretty well. I never forgot to look at those EGT's in flight and the adjustment range is small enough that you would really have to be asleep to damage the engine. However if you worry about it get an EGT with an alarm. Such a thing can be made with comparitors if you want to do an electronics project.

    It is very nice to be able to climb up and catch a tailwind. Also nice to be able to enrich the midrange if needed during a descent. Can't do that with the HAC.

    BTW, there wasn't much different about the carbs. In fact all the new 54's sold now have the same modification. It's a port in the venturi that give you "ported vacuum" to run the HAC. I added the port on one of my older carbs but you can pick up one that already has it on ebay. You only need one.


    FWIW,

    Mark
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  7. dholly added a post in a topic Kitfox 4 Mixer   

    Larry, I luv ya but after reading that comment I gotta speak up. All the guy needs is a handful of measurements. He's not looking for copyrighted CAD drawings, to steal a design, go into competition or enrich himself. He clearly prefers to fabricate, Jezuss just look at what he's stuck together. Probably costs a left nut to buy and ship kits or individual parts Down Under too. Hell, he can and will make the part and all he needs are a few friggin' measurements that he could easily jack off a buddy's Kitfox if he was somewhere with the benefit of a local fleet. C'mon brothers, loosen up and pay it forward. Share a little Kitfox love when you can!


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  8. Av8r3400 added a post in a topic Kitfox 4 Mixer   

    Not wanting to be flippant sounding, but the mixer assembly was one of the major improvements to the Kitfox line starting with the model IV. The engineering and R&D that went into this was fairly extensive and there is some intellectual property value here. This may be a reason that there are no drawings or technical details available for this component. Have you attempted to purchase one of these parts?

    I can appreciate the work of scratch-building a plane like this, quite impressive.
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  9. C5Engineer added a topic in Avidfoxflyers General Hangar   

    True HAC carbs
    Years back BING used to sell a carb that was different from the standard Bing 54. They are supposedly a true High Altitude Compensating carb. They sold for close to $800 back in the day for a set. I have a chance to grab to some brand new ones for around $500. If they will do the same thing as the Hac mixture control I'd prefer to go this route so I don't have to mess with the mixture control. It would only take once to forget to enrichen it coming down from 10K to burn up your engine. Curious if anyone is familiar with these. I only know one guy that has a set and he said his EGT's stay at 1150 no matter what altitude he goes to. Is there a reason they stopped selling them?? Thoughts??

    Some good reading here on the CPS site

    http://www.800-airwolf.com/pdffiles/ARTICLES/part35.pdf
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  10. Garyh added a post in a topic Kitfox 4 Mixer   

    Rust is a problem, so i keep spraying a coat of thin oil every couple of days to try and hold it at bay. The mixer is the last weldment section to do now
    before i can prime the frame, so i really nead this info as soon as possible. Anyhow thanks for your thoughts mate. Can anyone help garyh.9@bigpond.net.au Thanks Garyh.
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  11. dholly added a post in a topic Kitfox 4 Mixer   

    Gary- Scratch building like that earns my profound admiration, especially when I have a manufacturer's kit and manual in front of me. You must be retired and living in a desert climate? Leave a bare fuse unprotected like that around here and it would be flash rusted in about two days, lol. Best luck finishing the project, I'd help out if I could but I have a M-III.
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  12. akflyer added a post in a topic 582 crank   

    I'll third that one.. new seals and run it! No way would i drop 1200 plus on a new crank when you have a new crank in the engine.


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  13. napierm added a post in a topic 582 crank   

    I'll 2nd that unless there was a problem in storage (damp/humid/open intakes and exhaust) I would have a very hard time replacing a new style crankshaft with only 5 hours on it.
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  14. horsepower added a post in a topic 582 crank   



  15. egp8111 added a topic in Avidfoxflyers General Hangar   

    582 crank
    Hello All,

    I know this has probably been beat to death but I like your opinions on a 582 crank issue. I'm rebuilding a KFIII that has been sitting for about 8 years. I've sent the 582 greyhead off to a rotax tech for inspection. The crank was replaced new in 2002 and the engine run about only 5 hr. before it sat up. The tech says the crank is good in run out and the needle bearing he can see are fine but due to the fact that it is over 5 yrs. old and there are bearings he can't inspect he is suggesting I replace it. What is the groups thoughts ? Is it necessary to replace a crank with 5 hrs. on it ? My long term plans are to convert to a HKS or 912 but I'd like to get the plane up and flying first but if I have to sink to much money in this motor I might as well bite the bullet and do it now.

    thanks,

    EG
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  16. Garyh added a post in a topic Kitfox 4 Mixer   

    I have drawn a rough sketch of the KF/4 mixer, if any of you guys could put any of the dimensions on this would be greatfull. Cheers GaryH

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  17. Garyh added a post in a topic Kitfox 4 Mixer   

    Yeah, I am building a from scratch. and need these dimensions to construct this KF/4 mixer. A side view showing position in fuslage-arm lengths- the small
    linkages under the mixer etc. Pic shows where i am at this stage. Can anyone help.! Many Thanhs Garyh.

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  18. Av8r3400 added a post in a topic Kitfox 4 Mixer   


    Why? Do you need to repair one or are you trying to make one??
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  19. Garyh added a topic in Avidfoxflyers General Hangar   

    Kitfox 4 Mixer
    Hi all, do any of you guys know anyone with drawings for the KF/ 4 differential flaperon mixer??. Hope you can help?? Thanks Garyh
    • 10 replies
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  20. C5Engineer added a post in a topic Looking into VG's   

    Awesome response thanks!!
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  21. ski-bum added a post in a topic Looking into VG's   

    Joey,

    Here is an article written by Larry Martin, a friend of mine, on his experience with CCI VGs.

    Mike

    CCI VG’s on the Avid Flyer STOL by Larry Martin
    This is a report of my findings using CCI VG’s on the Avid Flyer STOL wing aircraft.
    Background:
    The aircraft is an Avid Flyer TD STOL wing with a Rotax 582, 3:1 gearbox, Culver 74×48 prop. Built according to the kit/plans with no modifications except for "Grove" landing gear. (heavier) Published allowable center of gravity is 11.185 to 16.5. This aircraft was at 13.5". Designed stall speed at approximately 900lbs in flight weight is 32.5 mph.
    The landing characteristics of this airplane were such that in order to affect a comfortable flare, power and additional speed was required beyond what I consider to be normal. In addition, there was insufficient nose up trim available on approach. On take-off, it was evident that the wings could fly sooner, but the airplane would not lift off. The tail could not be brought up before lift off speed, and would take off quicker from the 3-point attitude. The stall characteristics were such that when the airplane was gradually slowed to minimum speed, the airplane would sink, well above the designed wing stall speed. (Not with standing of course that indicated airspeed is most inaccurate at high angle of attack) The wing would not "break" at the stall, as most wings will. When the nose of the aircraft was "lobed" up and speed was allowed to bleed rapidly, the wing would exhibit traditional stall characteristics. It was determined that the elevator was not working sufficiently.
    After discussion with the designer of the aircraft, the center of gravity was moved to the published aft limit of 16.5" with the assurance that the aircraft was tested well beyond the published limit. For reasons of liability at that time, the published limit was set very conservatively. The aircraft was tested beyond 19.0", which can be safely used. (37% mac) The change in center of gravity helped considerably, but still not sufficient. Further to the designer’s recommendation, the elevator area was increased approximately 15% by extending the elevator aft. There is no room physically to change the horizontal stabilizer angle of incidence. Short of making a new one, modifications were complete.
    The flying characteristics at this point were much improved as measured by the following: A much shorter take off ground roll, the tail could be raised on take off with full flaps; almost sufficient elevator trim was available on approach with full flaps; and power off, full flap approaches could be safely made at normal speeds. The stall characteristics were similar, but at a slower indicated airspeed. Almost content with the airplane, but still not to the standard of performance that I thought it was capable of. I followed the studies of vortex generators.
    In the pursuit of finding the truth of if and how VGs would enhance performance, I read many studies and opinions. Some say that they help, others called it snake oil, etc. Art at CCI (http://www.vortexgenerator.net) was not in a hurry to sell me anything, but offered me aerodynamic and physics proofs and rebuttals. To say that he was patient is a huge understatement. Finally, he managed to overcome my skepticism, and I ordered a set with a money back guarantee. Art was first concerned about getting more lift from the tail, and we placed the VGs per his instructions on the flat surfaced (non airfoil) horizontal stab.
    The results of the VGs on the stab were nothing short of incredible and better result than the sum of what was done before this point. The tail was now producing more lift at all angles of attach. Subjectively, the tail felt more "alive". The take off run was even shorter, with the tail coming off the ground with the application of power. The increase of lift was objectively measured by comparing the neutral trim, hands off, level altitude minimum speed with and without the VG’s on the tail surface. A 10mph slower speed could hold level altitude with the VGs on. This was a dramatic increase in tail effectiveness. So much so, that I was able to remove 5# of ballast and move the CG .80" forward and have the same control feel. The stick position was physically further forward at all speeds, thus proving the elevators were working more effectively. The trim was effective at approach speed even with the cg further forward. (.5" cg change affects a considerable difference in this aircraft) The stall characteristics were such that the wing would stall at a higher angle, a noticeably slower IAS, and much more aft stick movement remained during the stall. Art then wanted to test the effectiveness of stabilizer end plates. There was a small subjective gain in effectiveness, but no objective, measurable results could be recorded. Most likely this was due to installation error inherent in the airspeed system. In addition to the enhanced low speed qualities, an unexpected gain in normal cruise speed of approximately 11% was attained. The top speed was approximately the same, but this is due to the large drag caused by the undercamber of the STOL wing. The airplane reaches a drag point similar to mach drag, in which the airplane will not accelerate above, or in the case of the Avid Stol, a disproportional increase in power only yields a minute increase in speed. It is not practical to fly at this speed. However; in the normal cruise range with a cruise rpm of 5400 yielded 84 mph with the vg’s on the tail. Without the vgs, the same rpm yielded 74mph. This is explained by the efficiencies of the tail.
    The next step was to install VG’s on the wing. Research shows that there is a wide range of "ideal" or "sweet spot" placement with respect to percentage of wing cord. Experience gained from others suggest that in a range from 4% to 12%, one would find that spot. CCI suggested 10% as a starting point. I initially placed them as per the supplied directions except I started at 7% and planned to move forward to 4% then aft to 10% to test the effectiveness. The results of the VG’s at 7% were immediately noticeable. The take-off roll was shorter. In slow flight, the stall occurred at a much higher angle of attach and the IAS was 5 mph slower. Again, I caution putting much emphasis in IAS, especially at high AOA due to position error. There is no argument that the AOA was much higher than ever before, and the airspeed needle was slower than previous witnessed. At 75+% power the nose attitude was extremely high and could remain this way flying at the verge of the stall. The Avid has "flaperons" which trail the wing. They are always flying, even in a stall. Therefore a subjective opinion of aileron control cannot be rendered. The Avid does not spin well and enters into a spiral instantly, so fast that I choose not to spin. I did fly a spin series, hoping that due to the higher AOA that was possible, it may spin. Unfortunately the spin qualities did not change, and with rudder application and a pivot of the wings, it becomes unstalled and spirals picking up speed very rapidly. Thus I still don’t spin.
    There was a gain in airspeed at the high end. It appears that the "stol wing drag point" was been changed to a higher speed. The old "aerodynamic drag point" is now easily overcome. I also noticed by way of control feel, and wing attitude that the center of pressure is moved forward on the wing. I replaced 5# in the tail to the original CG.
    The airplane was designed to be flown STOL. Dean Wilson designed the flaperons to enhance this ability. I use full flaperons for all take off and landings. I have landed with complete control in 20+ mph direct crosswinds with no problems. (grass strip) The VG’s do not detract from landing control nor do they negatively affect any of the flight characteristics. I am completely satisfied with the VG’s and help from CCI. Due to the satisfaction with the results, and my too busy schedule, I have not changed the VG placement from 7%. I would still like to, but it has to take a lower priority for the time being.
    Please feel free to contact me for further information. I heartily endorse CCI VG’s (http://www.vortexgenerator.net) if you want to fly the Avid the way it was made to fly!
    Larry Martin My93Avid@yahoo.com
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  22. C5Engineer added a topic in Avidfoxflyers General Hangar   

    Looking into VG's
    Who's got em? Worth it on a short chord wing like ours? The Rans S-7 guys swear by them. Thoughts?
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  23. dholly added a post in a topic Kitfox News Letters   

    Kitfox Owner Newsletter 1989



    Jan -

    Feb - Kitfox_O_News_Feb1989.pdf

    Mar - Kitfox_O_News_March1989.pdf

    Apr -

    May -

    Jun - Kitfox_O_News_June1989.pdf

    Jul -

    Aug -

    Sept - Kitfox_O_News_Sept1989.pdf

    Oct -

    Nov -

    Dec -


    Kitfox Optional Equipment List 1989


    Kitfox_Option_Equipm_Denney1989.pdf

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  24. akflyer added a post in a topic Kitfox News Letters   

    a couple more.. I am having problems uploading on my aircard so I will finish the rest tonight
    Kitfox_O_News_Feb1989.pdf
    Kitfox_O_News_June1989.pdf
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  25. akflyer added a topic in KitFox General Forum   

    Kitfox News Letters
    I have some newsletters that you may find useful. If you have additional letters post them up so we can get a complete collection of them!


    Kitfox_Brochure_Denney1989.pdf
    Kitfox_General_Info_Denney1989.pdf
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