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  1. EDMO


    As I said, when I spoke directly to Robbie, I asked him how large he can make the spring, width and height, to fit a Kitfox Model IV.  This is what I now have.

    Avid fuselage attachments are not the same as the Kitfox IV.

     

    Avid gear won't fly on a Kitfox, because it won't fit.  Nothing to do with pissy...

    Funny - Kitfox factory gear has been put on Avids - the fuselage fittings are the same.  Some members who I sold them to can verify that.  And Leni or someone talked about shortening the bungee tubes on the gear to strengthen and make it work.   It wont matter if Robby supplies the clamps and attachments to match gear and Kitfox 4.   Robby even has a diagram to custom order anything you want to design.   Best info is a call to him and tell him what you want.  EDMO

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  2. Av8r3400


    As I said, when I spoke directly to Robbie, I asked him how large he can make the spring, width and height, to fit a Kitfox Model IV.  This is what I now have.

    Avid fuselage attachments are not the same as the Kitfox IV.

     

    Avid gear won't fly on a Kitfox, because it won't fit.  Nothing to do with pissy...

  3. zadwit


    When I talked to Dean Wilson a few months ago about placement of the axle centerline on a tail dragger he had some interesting info.

    He said when the JN4 Jenny first came out, it had no brakes and on tail wheel, only a tail skid so the axle center line was placed real close to the loaded flying CG. This worked fine until brakes were installed then the planes started getting nosed over so the axle centerline was moved forward. He told me about the 12 degree angle. IF you level the plane, drop a plumb bob thru the CG on the wing and then measure off that vertical line forward 12 degrees is about all you want . More than that makes the plane hard to control on the ground.

    A lot less and you are prone to nose over... There has to be  a happy medium especially if operating on skis, plus wouldnt it be nice if you had more precise control on takeoff without the damn plane trying to Eat you all the time?????!!?

    1 person likes this
  4. EDMO


    The larger gear for the 5-7ss won't work on a 4.  Neither will an Avid Spring.  They are 5" wide, where the Kitfox IV is 4".

    What I had them do for me is the largest possible, still fitting the properly engineered mounts for that airframe.  Been there, done that.

    Larry,  I didn't say to use the Kitfox 5-7 1550 GW spring gear - just ask Robby to make the KF 4 gear 8" wider to compare with Avid 4 at 66" wide, or the KF5-7 gear which is 68" wide.  The Avid 7075 spring is 4" or 4.5" wide now,  and the thickness has probably changed with the 7075, since it is 8 pounds lighter, same as Kitfox 4, and Avid gear should work on the Kitfox 4 because the fuselage attachments are the same.  He can ask Robby Grove.   I know Avid gear wouldn't fly on TKF, but we are not on that pissy site!   ;<)  EDMO

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  5. Av8r3400


    The larger gear for the 5-7ss won't work on a 4.  Neither will an Avid Spring.  They are 5" wide, where the Kitfox IV is 4".

    What I had them do for me is the largest possible, still fitting the properly engineered mounts for that airframe.  Been there, done that.

  6. zadwit


    There is a formula that aircraft designers use for TW aircraft. The determine the aft CG loaded for flight, level  the aircraft and draw a line vertical thru the CG. Then they measure 12 degrees from the CG forward and that line shoujld  not go thru the axles center line. If it does, it make the airplane very tail heavy and hard or nearly impossible to control. Ironically I read this in Design for flying by Dave Thurston, aeronautical engineer and a few days before I read it I was talkeing to Dean Wilson about trouble with ground handling on my Ridge Runner 1. Guess what, the Axle center line is 20 degrees maybe a little more ahead of the Datum, with plane loaded aft CG ready to fly on the Ridge Runner which is why it is such a squirrel on the ground. The Main gear axles are 8.75" fwd of the WLE on the Ridge Runner 1. When loaded to most fwd CG the angle from CG to axle is 10 degrees but it will never be there bevause the fat pilot is 22" aft!!!! so most of the time the wing CG is at the aft limit of 16 inches.........

    The tail is slow to come up even with a 503, a bigger engine than designed.. and it wanders all over the runway. Does not want to go straight. The closer the axle centerline is to the loading flying CG, the more stable ground handling, easier to nose over, but tail  comes up quik.  Partly at Play on the PA-180150 is the engine is canted down on the mount, the engine is powerful and so the thrust line is above the axles quite a ways which all adds to lifting the tail quickly.  COnverted Tri pacer to tailwheel were terrible  on skis because you could not get the tail up out of the snow so takeoff runs for very long. The PA20 was not as bad because it had more down elevator travbel,, a lot more down travel.

     

    Same problem  on the TexasTail Dragger Cessna 150, the gear so far fwd impossible to pickup the tail on takeoff so in the snow a real problem....

    I have not measured the angle on a PA 18 but I looked this info up. Datum is Wing Leading Edge (WLE)

    Axles centerline is 2" aft of the datum. Level the plane  and the axle will be 2" aft of the WLE, the CG  is still farther aft,

    CG range is 10.5" to 20" aft of the WLE on PA-180150

    YOu would need a scale dwg of a pa-18, mark the CG location fwd and aft, then draw a line 12 degrees thru the CG at the wing down towards the axles and see what it measures..

     

     

  7. dholly


    The kits I had last year started out the same, a KF3 w/ the KF4 wing and differential control retrofit kits. However, because the seller said all parts were purchased separately, I was really wondering whether they upgraded to the heavier 4-1200 lift struts. If so, would be easy to strengthen that fuse for 1200lb MTOW, particularly with that gear IMO. And it would be on the data plate and op lims. This could be a real good buy for someone. What was the BS ad price?

  8. EDMO


    I would get a quote from Grove to make this gear 8" wider, like the KF5-7, and 2" taller if you wish.  The Grove gear for Avid 4 is 66" wide.  You could use it because I think the mount fittings will interchange.  I think I told you I have complete set of 6" wheels, brakes, external disks (NOT like the internal disks used on 8" wheels), tires and 1.25"? axles for $400 + shipping, but you have to specify the axle bolt spacing before you order gear from Grove.   I can copy the Avid picture and dimensions if you want it.  You will have to get the attachment fittings which are about $500 now?  The prices for the Avid gear are old - so add about $1000.   Grove gear is now 7075 Aluminum and is lighter than the old 2024 models.  EDMO 

     

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  9. Av8r3400


    That is the standard Grove gear and it works great.

    I had that on my previous Kitfox IV-1050.  I used the Grove 6 x 6" wheels and double puck brakes because I HATED the Matco brakes on the bungee gear.  I didn't like the look of the wide Nanco/Nanking/King Fox ATV tires and wanted to go to a more durable aircraft tire.  I settled on 21 x 800-6 Aero Classic tires from Desser.  They were affordable, durable and plenty big for my needs.  To do this conversion, I already had the parts from my project plane so I cannibalized them as a learning experience to see if I would do the same on the new plane I was building.  It worked out very well.  

    I chose to do the slightly longer spring on the Mangy for more ground clearance and a better 3-point angle of attack after talking with Robbie Grove.  Since I was building the plane at the time I reinforced the side longeron truss to strengthen this area in anticipation of the longer gear legs and possible future Bushwheel tires.

    The investment to do the complete Grove system is substantial.  Wheels, brakes, gear and tires will set you back $3500 or more.  From my experience, this was money well spent in the performance gains I experienced.  Some may not agree with this, but I have been very happy and do not regret spending the money.

  10. zadwit


    I have standard Main Gear Legs on this 1999 Kitfox Classic IV with8" douglas wheels and  matco single piston brakes and King Fox tires.. I am pretty sure the axles  are 3/4" diameter.

    I am trying to decide if I should order up a Grove landing gear to replace what I currently have. Should I ask for 2" taller gear???? mainly I am looking for stability improvement on ground handling during takeoff and landings and I have read that lots of people say the wider gear legs improve the ground handling.. IF I order the Grove gear legs and install their 3/4" heat treated axles, I have seen a couple of them that have failed, probably due to overload however it looks to be the  weak link  in the gear .Still they were ground loops.....not normal loads....

    It would be nice to have a set of 8:00x6 tires and wheels for general flying and a set of 20" soft tundra tires for other stuff rougher places... 

    Just looking for ideas of how to proceed..... Is this the Grove gear I want or should I order something else????

    Kitfox Model 3 & 4
    Wheels
    Axles
    Hardware

    Installation Instructions
    Kitfox Model 3 & 4 Landing Gear

     

    Gross Weight: 1200 lbs.
    Weight:  24.3 lbs.
    Material: 7075-T6 Aluminum
    Axle Bolt Hole Pattern: Type 1
    Includes Gundrilled Brake Line
    P/N 1021-3   Price: $1,995

    Thanks, Mark Smith in Davenport

     

  11. bcbushcaddy


    Hello everyone, 

    Just a quick heads up that while flying with a student yesterday in his PA-17 powered by a C-85 I had a partial engine failure in the circuit. We were working on runway changes so at time of the failure a bit further out on downwind as usual and unable to return to the pavement, safety concerns with houses, power lines, highways etc. 

    Anyhow, as I showed him once more pre-landing power reduction by pulling carb heat prior to throttle reduction the engine nearly died. Also the carb heat cable came out slightly further as it used to. I immediately pushed the nose down a bit, pushed the carb heat back in - no change 500 - 700 rpm rough at best. Reduce speed to best glide, look out below, check fuel, 3/4 tank, fuel valve on, bla bla bla ..while slowly sinking towards unfriendly terrain below. At this point I started cycling the engine and after several cycles it seemed to stabilize at about 1900 - 2000 rpm, ..time to look for a landing site, open terrain below and possibly nurse it back to the airport. No luck, can't maintain altitude so out over a small valley we go to get additional heights in the sinking game. It is also fairly open and has a few frozen ponds (barely frozen) in it that can be used as a last resort scenario. But no power lines, roads, houses, and if needed a bit of room to select the best bad place there is, since there really is no good ones. 

    Knowing of an old airstrip in the area and realizing that going back to CZML was a no go we decided to use the old field. It has some fairly tall trees at the approach and a new fence (hard to see near dusk) about 1/3 down, ..never mind its all we got. Over the trees we go, lean it over into a nice slip towards the fence, level off, flare, touch down, roll out, full brakes, watch the ditch, big rock, bull wallows and and we come to halt, ..best of all right side up and not a scratch on the plane. 

    After shut down and inspection I put my fingers up the hot air bleed hole of the box and immediately could feel the butterfly valve laying on the bottom of the box. Upon removing the filter it was rather obvious that some really poor workmanship was to blame and a secondary, possible 3rd repair and brazing failed - see photos. It partially occluded the intake and reduced the amount of air needed for the engine to run properly.

    So if anyone is using an old carb heat box, they are now 60 years old, things fail, don't be afraid to check it good on your next annual. Look at the welds!! Anytime you pull that filter, give that Butterfly Valve a good hands on wiggle, not just a visual. Ideally spend a couple hundred bucks for a new one and get a peace of mind with it.  And also, anyone telling you that certified engines are better than your Rotax, Subaru or Yamaha, because they never fail, ..I beg to differ. Certified Aircraft engines have problems too and I could go on for some time listing issues here. But the point here is, that a look is good, a hands on wiggle better and new box ideal. So for all those on this forum or maybe your friends that are bombing around with an old C-65, 75, 85, 90 you name it, ..maybe check that old airbox and the welds. Was a first for us, but there is lots of them out there. Stay safe! 

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    3 people like this
  12. bcbushcaddy


    REALLY?! I've been following this threat with great interest as I had the opportunity to see Willis' (Marshawk) Yamaha Conversion come to live with Teal's help. I don't have a re-drive or Yamaha yet, ..but don't think it will ever be bearing a Mohawk sticker.  Just my .02 cents! ;-) 

    1 person likes this
  13. bcbushcaddy


    Thanks EDMO, it is actually good input as it leads to yet another discussion and thats on the benefit of the lower bearing. My first ever Johnson re-drive built from plans and parts also did not have the lower bearing, nor did several other belt drive systems such as Stratus or even Raven if I remember correctly. The biggest problem for me is the paint job, looks good but really bugs me for tolerance and ability to trust the torque settings over time. Next, and I will have to check that yet, is to micrometer the Subaru Crankshaft Flange and possible "runout" into the shaft end inside the front bearing. Let's just say that the tolerances used in the machining of the drive (way back when, 80's, 90's) are not quite CNC and what one might expect of being made today. And it's experimental and there should be a certain expectation that it will work but might need some fine tuning. And there is the fact they were built as a one of at the time and there is installation variations from builder to builder no doubt. Anyhow front the shaft has been sleeved, going to post some photos next time and hopefully some more info on the runout issue if there is any. 

    Thanks again EDMO, ...hang in there! With best wishes, 

  14. NorthIdahoAvidflyer


    While your screen is out consider painting or wrapping satin black vinyl around the 2struts from your dash top as these reflect on the screen and can ruin some photos.

    I took your advice and painted the two down tubes. Now to get the windshield back in. Thanks again for the suggestion Dusty. 

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    1 person likes this
  15. TJay


    played with the Kitfox today. After scratching my head a bunch I think I finally came up with a decent heater idea. Not quite done with it yet I need to hook up the intake tube yet.  It will take air from the front of the engine ram air duct thats for another day. As you can see from the pictures the air will flow right through the heat muff and out the bottom through the trap door for summer time operation. Pull the cable on the dash and the trap door closes then air is forced into the cabin. I also packed the inside of the heat muff with stainless steel scrubbing pads. It is all made form Aluminum so the scat tubing is about the heaviest part. Hope it works

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    2 people like this
  16. Chris


    Thanks all for the words so far.  I had her send me pics of the engine and airframe logs.  Nothing abnormal, and no mention of any resigning, so I'm assuming original 2000 Ceconite.  What's the collective wisdom on 11 year old skins?

    nlappos mentioned the serial number should end in D.  This one is N9032K.

    I found this on the web: and a couple pictures too.

    Folding Wing LSA: Manufactured in 2000, Professionally built and covered with Ceconite.
    Airframe: 124 hours TTAF
    Engine: 231 hours TTE Rotax 582
    Prop: 3 blade warp drive prop
    Avionics:
     Portable VHF NAV/COM radio with VOR/NAV
     Intercom
    Stick mounted push to talk switches
     Garmin Transponder with altitude encoding
     Instruments:
    AS, ALT, T&B, VSI, Tach, EGT, Water Temp, Compass, ELT, Strobe/Position/Nav and Landing Lights
    BRS chute
    Two 14 gal wing tanks
    Wheel Pants
    Wide Ldg Gear 
    Trailer included

    No known damage and no corrosion
    Nice Light Sport airplane

    Fresh Annual

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  17. EDMO


    I am wondering if instead of nylon we could use teflon (PTFE) instead? Anyone have experience with this?

     

    https://dir.indiamart.com/hyderabad/ptfe-bushes.html

     

    I used Teflon on my Cessna & Ercoupe steering wheel tube supports to replace the rubber rings - was a little tight, but hit it with a quick shot of WD40 and it was slick as owl shit.  Teflon is slicker, but softer and will wear faster - and is/was more expensive.  EDMO