Activity Stream

Activity Stream

  1. dholly added a post in a topic Amphib Float Controls   

    The weight issue continues to eat at me. If I build super light and use the Jab2200 sitting in the closet, I know it will work but still wonder if I'll be happy with off the water performance. If I use a 912 or Sube I'll be underfloated, perhaps seriously and dangerously so. I've almost conceded to myself these floats which I bought for my Mk-IV are just too small for the Avid+ install. To make matters worse, I have had several fair offers on the amphibs and a buddy is selling a set of next-to-new Baumann 1500 straight floats only 45min drive away. Where's that winning Lottery ticket when you need it??

    Decisions, decisions...

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  2. Trackwelder added a post in a topic Amphib Float Controls   

    Looks like you have been staying busy, though it looks like one of those projects that takes forever and doesn't seem to amount to much. Keep up the good work and keep pictures coming.


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  3. akflyer added a post in a topic Pic request   


    best pic I have right now is one of the ones I took when I found mine under the tarp....



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  4. horsepower added a post in a topic How to tell if it's a MKIV   

    Leni if you can use the Kitfox 4 engine mount for your new motor build I still have it.It has the new style 582 side mounts but you may be able to make it work.You pay the freight up there and you can have it.I doubt I will ever use it. Randy
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  5. C5Engineer added a topic in Avidfoxflyers General Hangar   

    Pic request
    Can someone take some detailed pictures of where their brake master cylinder bottom tabs attach to the rudder bars and post for me? I have to weld the tabs on as part of brake conversion and want to make sure I get them placed right so the geometry works out.

    Thanks!
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  6. akflyer added a post in a topic How to tell if it's a MKIV   


    07 arctic cat 800 that my nephew wrapped around a tree.... Should put the 670 to shame in a big way, reliably


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  7. C5Engineer added a post in a topic How to tell if it's a MKIV   

    What did you end up getting? You been in touch with Snaps yet? His 670 powered Avid Float plane is awesome.
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  8. dholly added a post in a topic How to tell if it's a MKIV   

    Joey, experimental kit and home building always leads to individual builder modifications and tweaks etc... I think it's inevitable some of the latest and greatest Avid upgrades found their way to older models as owners continued to tinker. Not to mention early Mk-IVs did not incorporate all the Mk-IV upgrades listed, depending on manufacture date. For example, while the later Mk-IVs had them, my Mk-IV S/N 1127D did not have the rear carry thru gussets in place when sold from the factory so they were added after the fact (pic). Plus, Avid itself sent out many 'unusual' iterations containing parts from different models at times depending on inventory. That's why I posted the whole list and S/N's. Leni's suggestion to call Airdale with a S/N is great if you have it, otherwise the more pieces of the puzzle a buyer can put together the higher confidence they will have it is a true Mk-IV from the factory.

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  9. akflyer added a post in a topic How to tell if it's a MKIV   


    Not much. When mine was built, it had most of the Mk IV upgrades, then I did a few more when I rebuilt it. The main difference in mine now is the door latches, motor mount and cowling. I still have the "C" cowling till I can free up some funds to complete my upgrades! I am sure I will be going to the MK IV cowling when I get the new engine built up as I will need more room under the hood for the exhaust etc. Should be starting on the engine mods mid next week, atleast getting the adapter for the gear box machined etc.


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  10. C5Engineer added a post in a topic How to tell if it's a MKIV   


    I stand corrected...was not aware of that. What's the difference between yours a IV then?
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  11. racegunz added a post in a topic How to tell if it's a MKIV   

    Thanks! what a great group if any of you are ever around Indianapolis give me a heads up, I'll buy you lunch.
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  12. akflyer added a post in a topic How to tell if it's a MKIV   

    <br /><br /><br />
    not necessarily, mine has baggage behind seat and round rudder... but it is still a "C"
    The serial number would be the best way. get the # then call brett at airdale and ask him to double check if the paperwork etc does not readily tell you what it is.


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  13. C5Engineer added a post in a topic How to tell if it's a MKIV   

    The easiest way to tell is probably whether or not it has the baggage compt behind the seat and a round rudder.
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  14. dholly added a post in a topic How to tell if it's a MKIV   


    This should help...


    Theoretically MkIV's came into effect at kit ser # 1000 BUT it was
    more like 1100---have the details somewhere.
    Anyway....some work for you ---tee hee heee.
    Does it have the Taildragger gear legs with the step?
    Does it have a 1/1/2" Tailspring necked down to take a MAULE Tailwheel?
    Does it have Elevator with inset trim Tab?
    Does it have Round Rudder?
    Does it have Dorsal steel stringer---i.e Fin tube goes to the T'Deck
    FIN NOT OFFSET
    Does it have a baggage locker?
    Does it have Gas strut fixings just behind left shoulder in fuse frame?
    Does it have Triangular steel welded gussets in EACH corner of the
    "quarterlight window" one gusset is Seat Belt Anchor point.
    Does it have Fiberglass seat?
    Does it have Spring Loaded Door latches?
    Does it have Gusset from Top rear carry thru tube, L&R, outside the
    fuse side frame, welded to the rear Spar Bolt attach bushing---a bit
    like a shelf bracket.
    Does it have two Strap like Plates welded on Rear Wing Carry thru tube
    to inside of rear door post?
    Are ends of Wing Carry thru tubes welded closed?
    Does it have two plates for Fuel Tap behind Vernier Throttle mounting
    plate?
    Are there "glue plates" welded at rear of fuse where inspection plate
    could be fitted for theelevator Push Pull Tube Clevis Fork end they
    Go from Fuse to Fin Spar.
    Are fuselage tubes at this point sort of splayed /opened out for
    greater Bolt clearance?
    There are a couple of other subtle points that can't be checked unless
    tubes cut -- as Avid upgraded some Tube wall thicknesses to get Gross
    up to 1150/1200lbs.
    BUT These should keep you busy for a short while---
    and Send everybody with a "MKIV" running to check!!! heee heee..
    Have fun,
    Regards,
    Steve at Airdale...


    Also...


    Looking at our log book (Airdale's) it shows your SN 1388C as
    a C Model STOL TD. The serial numbers before, back to about SN 1025 are listed
    as MKIVs but with a D after the number (as your's has a C). The serial numbers
    after yours are also listed as D's with the designation of MkIV etc. Hope this
    doesn't muddy the water more.
    Jerry at Airdale

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  15. dholly added a post in a topic Amphib Float Controls   

    Well, after much head scratching, I ripped it all out. A thread came up on the kitfox list about converting the aerocet amphibs to electric actuators and I decided to go this route to eliminate the hassle of retrofitting the KF controls to my Avid+, freeing up cockpit room by removing that big Johnson Bar and the weight savings. Ron offered the info to the public so I'll share what he sent me. Thanks Ron.
    __________________________

    The changeover from cable operated to electrically operated Aerocet 1100 amphibs was my own experiment. The following illustrates my own experience and is not a construction guide. All of the materials used, except the actuators, came from my stash of scrap metals and spare parts and therefore are probably heavier and stronger than required. Still I saved cose to 2 lbs over the cable operated mechanism. All of the cables were removed from the floats. I never had installed the Johnson bar. The large control pulley was replaced by a lever 4 5/8†in length centre to centre. The small control pulley with the rest of the nosegear mechanism stayed in place.



    I built an adjustable bracket – the adjustment part turned out to be not necessary.



    The actuator I used is a Firgelli 8†throw, obtained on line, but there are other brands suitable. I made the mistake of buying an actuator with a built-in potentiometer, thinking I could mount a gauge on the panel indicating the position of the wheel. I discarded the idea when it came to me that if the linkage breaks the reading would show the actuator position but not the wheel position.



    The bulkhead where formerly the cables were anchored was re-enforced with fiberglass and sheet aluminum, then notched at the top for the actuator to pass through and then the assembly was bolted on. Pic shows wheel up position.



    The next picture shows test installation. I covered the actuators with appropriate rubber boots to protect against moisture. The electrical cables are long enough to reach just inside the fuselage where I used automotive receptacles to connect them with cables to the two way switch on the panel. This helps in quick removal of the floats for changeover to wheels.



    To positively identify the up position of the wheels I installed a microswitch which is activated by a lever mounted to the idler pin (Part number 480-5042) of the main link (part number 480-6080-10) powering two LED lights on the panel. The microswitch in the picture will be replaced for the coming season by a waterproof switch since the one below shows some corrosion after only one season. The electrical cables are also equipped with receptacles for quick disconnect.



    Finally I have installed a main retract system switch as well as the two way switch to avoid a problem if I accidentally retract or deploy the system on the ground. This would overstress and break the linkage. By the way, Datum Air, a manufacturer of wheel penetrating skis and conversion kits for electrically operated Puddle Jumper floats, is seriously thinking of developing a conversion kit for Aerocet 1100 floats. You can visit them on line www.datumair.com
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  16. racegunz added a topic in Avid Model IV   

    How to tell if it's a MKIV
    What are the things to look for? How do I tell if it's a MKIV vs others?
    • 39 replies
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  17. dholly added a post in a topic Catalina Gross Weight?   

    Leni, if you already have the .083 spars w/ ribs 12"o.c., with your beefed lift struts it certainly sounds to me like simply adding an extra bay or two is the way to go. The only question left is with the greater bending moments etc, so it seems the brackets and adjustable lift strut end become the point of failure weak links. Did you use the standard ply stiffener or did you beef those too? Remember, the HH wing was stress tested and passed even without the original oem stiffener but, IMHO, you would be wise to strengthen the bracket area if you add wing area. Two additional bays on a HH wing adds, what, almost 15-20% surface? That seems like it would put the wing a long ways out of original design stress specs to me and the bending is what causes risers so the more you can do to stiffen the wing the better, right? You can see from the Magnum stiffener history that a relatively simple change can make a huge difference there. Just a though but that said, since Avid/Airdale actually did/do offer a wing extension kit, I suspect someone with more than an armchair aeronautical engineering background passed off on it so maybe we are all over thinking it. One thing for certain, washout adds up fast on a longer than norm wing if you used 2" twist per the manual. Have read that creates real issues w/ speed wing regarding more loss of top speed than lift created but I assume much less of a problem with the under camber ribs.

    BTW, there is a new Catalina listing on Barnstormers in the past day or so if anyone is looking. Location was Maine I think, looked clean w/ very low time 582...
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  18. akflyer added a post in a topic Catalina Gross Weight?   

    hmmm didnt think about just extending my wings and not the struts. when I made new struts for mine I used 1" X .059" tubing. hmmm now you have me thinking about just making extensions for mine and moving the flaperons out to the end. I sure wish Steve would show up on the lists again and give us some words of wisdom.

    How is your build coming along? updates have not been real stellar from the chunky avid club lately


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  19. dholly added a post in a topic Go Kart to Matco Brakes   

    That's some dead sexy Avid shiznit right there!
    Be interesting to see how these affect your rotation and cruise speeds.
    Figure the weight diff yet?
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  20. dholly added a post in a topic Catalina Gross Weight?   

    Leni, I guess I look at the 'more mtow' vs. 'more lift' as being two separate goals. I remember Steve W saying on the other site it was ok to add tip extensions to HH wings without moving the wing strut attach brackets out or going to longer 1" struts like the Magnum, but I always just assumed it was to gain more lift not increase mtow. Maybe he's right there is enough stress safety factor built in to counter extra weight or any adverse change in bending moments or g load due to the unchanged lift strut position. Personally, I would be uncomfortable with that if I was placing a lot of stress on my plane/wings plopping in and yanking out of tight AK gravel bars like you guys do. In any event, if the Cat wings are rated for 1200# adding them to a 1200# or lighter Avid, particularly if floated, might be worth it for extra lift but fitting them to a 1250# Avid+ would cost Randy and me 50# mtow. I'd probably shy away from using the Cat lift struts too. IIRC, they use 7/8" x .035 wall 4130 lift struts with 2 jury struts because they failed at 1150# gross with only one. The 1" x .049 wall 4130 lift and single jury strut used on the Airdale and Magnum sound stronger and less draggy too. Either way, extending HH wings using existing struts/brackets or adding longer Cat wings may get you more lift from the larger wing surface, but how much of the gain in lift performance will be offset by the added weight? I'm not suggesting it is a show-stopper, I have no idea, but would definitely be interesting to find out. You've done crazier things, go for it!
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  21. akflyer added a post in a topic Avid Catalina   

    Here is a few shots of the progress on the bird. Lotsa fiberglass work to the sponsons on the hull. If you remember right in the original pics, they were very wavy possibly from sitting in the sun and the high temps having their way with them. Some honeycomb composite, and glass work and they are now tougher than hell and straight!



    New glass work on the sponsons



    Old mechanical brakes



    New matco Brakes



    Tail feathers in polybrush



    Tail feathers in the first coat of silver

    Looking good Bob, keep at it, spring is right around the corner and I wanna see this bird fly!


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  22. akflyer added a post in a topic Catalina Gross Weight?   


    Doug, the thought was the catalina wing is longer... and would be better for the heavier fat bastards.... in fact, I want to build plug in tips for mine to extend them out. Would be nothing to whip up a longer set of struts etc. to make them the same length as the catalina... more wing is more lift, is slower flight for me... I like getting in and out short, especially on floats


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  23. dholly added a post in a topic Catalina Gross Weight?   

    Randy,

    It is my understanding the Airdale uses the same 144"L x .083" wall T6061 spars as our Mk-IV HH and Avid+. After a lot of time researching this, I came to the conclusion that building new Airdale or Magnum wings for my Avid+ was alot of wasted time and expense. According to Steve W., the Airdale wings use steel vs. alum drag tubes w/gussets for the higher compressive loads, along with 1" x .049 wall 4130 lift struts and an aluminum spar stiffener identical to the original Magnum, which was similar in shape to the plywood MkIV HH stiffener but longer. Of course, there are other airframe and gear modifications inherent to the Airdale that together add up to the 1400#, which we cannot retrofit. What I did do in my own quest for increased mtow was modify my stiffeners. Here's an excerpt from my log explaining my rationale:



    The kit manufacturer's suggested gross weight rating for my old Avid Mk-IV with Heavy Hauler wing (144"L x .083" wall T6061 spars, 7/8" x .035" wall 4130 lift struts, aluminum drag tubes, ribs 12" o.c. and 1/4" x 16" ply spar stiffeners) was 1200lbs. By comparison, the suggested gross of the Avid+ with the exact same wing, excepting 1/4" x 18" ply wing spar stiffeners, is 1250lb., due primarily to a stronger fuselage. I decided to replace the 1/4" x 18" ply wing spar stiffeners supplied with the Avid+ kit (part W-24, inserted into the spars and secured under the lift strut brackets) in favor of a longer, stronger spar stiffener design similar to that used in the Avid Magnum. My goal in doing so is to safely increase useful load by an additional 70lbs, to the Light Sport Aircraft max of 1320lbs.

    The rationale... early Avid Magnum design at 1500lbs. gross, used identical 0.83" spars and ribs, but added 1" x .049 wall 4130 lift struts, steel drag tubes (vs. aluminum) and 1/4" x 24" long ply stiffeners. Shortly afterward, Magnum gwt was increased to 1650lbs. with the addition of 1/8" x 24" aluminum stiffeners similar in shape/size as the original plywood type, however, two strips of 1/8" x 1/2" aluminum were riveted along the top edge of the aluminum stiffener to form a kind of 'T-Beam'. All other wing components being equal, the new stiffener allowed for a 150lb. (10%) gwt. increase according to the kit manufacturer. Even later, gwt was raised to 1750lbs. with the addition of a 36" extruded aluminum 'I-Beam' stiffener. So obviously, adding beefed-up 'Magnum style' spar stiffeners will strengthen the Avid+ wing. Since 70lbs. would represent a 5.6% increase in gwt for the Avid+... about one-half the 10% factory increase on the Magnum for essentially the same stiffener modification... I do not think the possibility of raising my gwt by 70lbs. after the stiffener mod is either unfounded or dangerously unrealistic.

    However, I am mindful there are several other areas in the wing that run out of 'stress related' safety factor margin over 1250lbs that must be considered as well, ie., Heim adjustable rod end, rod end attach bolts, rod end welded screw thread, the root attach bolt and bushings, the wing attach bolts, the lift strut attach brackets and the carry through tubes. Further, the wing and related components are only one small part of the gross operating load capacity equation and there are many other inter-related items to take into consideration. Landing gear, bungees, tailwheel, tailspring, attach bushings, attach bolts, wheels, brakes, axles, fuselage tube i.d. and o.d., bigger rudder, larger elevator, trim tab requirement, heavier duty fabric etc., all come into play.

    To be conservative and safe, I will do calculations on the wing loading and consult the G forces per bank angle charts. For a slightly higher useful load, I would limit operation in turbulence and keep bank angles below 75*-80* degrees (probably not a huge problem with amphib floats hanging under!), if necessary. At 1320lbs. gwt., useful load with pilot, passenger and gear would increase from 450lbs. to 520lbs. (or from 300lbs. to 370lbs. with full fuel, and from 375lbs. to 445lbs. with half fuel) on the amphib floats. In any event, this will be a good 'weight for safety' trade off. At 4.2ozs. for the original W-24 ply vs. 17.5ozs. each for my new wooden 'I-Beam' stiffeners, the weight penalty is 13.3oz. each x (4) stiffeners = 53.2ozs., or about 3-1/3lbs. total. One other alternative: adding a 12" length of hardwood shoe mold to both sides top and bottom of the supplied W-24 stiffener. This weighs out at 10.3ozs. each, or a total weight penalty of ~1-1/2lbs. total.

    Of course YMMV but, along with the foregoing armchair engineering, I think the Avid wing load test results and long history of all those Avids and Kitfoxes flying 70lbs heavy regularly lead me to feel comfortable with a mtow between 1250 and 1320 after simply modifying the stiffener. Since I made mine, I heard Just Aircraft came out with an extruded aluminum 'I'-Beam style stiffener that fits the I.D. of the .083 spar, might be worth a call.

    Cheers,
    Doug
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  24. C5Engineer added a post in a topic Go Kart to Matco Brakes   

    I went flying this afternoon and took one of the new tires for a side by side shot...Yehaw these are gonna be fun!




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  25. akflyer added a post in a topic Catalina Gross Weight?   


    Most things I have read were in line with what Joey said. VNE was due to no rib stitching, and over the evolution, I belive the VNE was increased to 125 or 130 with rib stitching. I have had mine to 125 and nothing ripped off, but the flapperons were pretty heavy feeling

    I do 110 descents all the time.

    I also think the 1200 was more what the hull would float safely than a wing issue. It sounds like at 1200 you are sitting pretty low in the water and get some pretty good splashing. I would not be afraid to go up to 1320 but would probably not be trying to do any snaps or spins with it at the full 1320


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