herman pahls

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Everything posted by herman pahls



  1. herman pahls added a post in a topic Avid visability   

    I have been flying my Kitfox for 18 years and have managed with the  round cowl visability.
    I powered my Kitfox with a Jabiru for a few years and used the Skyfox cowl that is similar to the Avid cowl in that it was 2-3 inches lower on the windscreen.
    The Jabiru did not meet my high altitude and short field needs but a really appreciated the added visability the Jabiru cowl offered.
    Good question regarding the thrust line.
    I am not sure the Avid upside down 582 installation (spark plugs down) changes the thrust line much from a Kitfox 582 spark plugs up installation.
    The Avid installation places the prop flange as the high point of the engine installation allowing for a lower cowl and the Kitfox  has the prop flange several inches below the spark plugs.
    Another advantage of the Avid 582 installation is that the 582 exhaust does not need to be modified to fit in the cowl and produces a few more HP than the Kitfox 582 installation.
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  2. herman pahls added a post in a topic Let's talk gear geometry   

    Great topic since I have been researching gear design for the last week.
    John Roberts said the front gear leg takes the greatest load and is in compression so that is why it needs to be beefier and braced like your new version is to prevent it from collapsing.
    Extending and widening the gear also requires bigger diameters and wall thickness to prevent tube failure on compression.
    Roberts also said the gear and cabane attach points need to be designed so the forces are applied inline with the longerons instead of twisting the longerons.
    That explains why most cub style cabanes use separate attach points from the gear leg.
    I was surprized to see at the High Sierra fly in that Pops Dory was not using bungees on his new Cub.
    As long as the springs have enough travel to prevent metal on metal for reasonable hard hits, they sure look like the way to go.
    My off road car has 2 springs per shock.
    When lighter spring bottoms out the stiffer second spring takes over for progressive action.
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  3. herman pahls added a post in a topic Avid visability   

    The Avid Model C that I measured to find out how the gear placement compared to a Kitfox had an upside down 582 with cheek radiators.
    I now understand why the upside down 582 in an Avid allows the cowl to be lower than a Kitfox for better visability.
    It appears that the  top 4 of the 6 Avid 582 engine mount bolts would come  close to fitting the Kitfox.
    Otherwise the Avid and Kitfox engine mount attachment to the fuselage firewall are not even close to interchanging.
    Without a custom engine mount I will not be lowering my Kitfox cowl for the better Avid visability. 
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  4. herman pahls added a post in a topic Landing gear safety cables   

    I measured an Avid Mark 4 and an Avid Model C today and you are correct, the gear attach points on the longerons are almost Identical to within a 1/16" of my Model 2 Kitfox or less and could be adjusted with a file.
    All 3 aircraft are within a 1/2" of axle placement in relation to the leading edge of the wing when the fuselage lower longerons are level as when doing C. of G. calculations.
    Av8r3400 said his friend recently ordered a swept forward gear for his Model C Avid, which according to Trackwelder and my measurements should fit the early Kitfox's that do not have the forward float attach points.
    According to Grove's website, their Avid Mark 4 TD gear costs $300. more and weighs 8 pounds more than a Model 3-4 gear.
    The reason for the increased weight is the extra material needed for the forward swept feature of the gear and that it is 5" instead of 4" wide where it clamps to the attachment brackets.
    Av8r3400 said the Grove gear on his Model 4 increase  his empty weight 12 pounds over the stock bungee gear which I could live with.
    Since my Kitfox would require the swept forward gear, the weight increase would approach 20 pounds which I do not think I can live with.
    Thanks for all the comments to help me come to a conclusion.
     
    Where do I find Steve Winder's posts on how to reinforce the seat-bungee truss?
     
    Thanks  Herman
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  5. herman pahls added a post in a topic Landing gear safety cables   

    I have a model 2 Kitfox.
    I will refer to your friends Avid gear when I call Grove.
    I was under the impression that the gear attach points on the early Avids and Fox's were the same.
    If that is true, maybe Grove does not know that and that is why they say I need a custom gear and I need to make my own attachment blocks.
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  6. herman pahls added a post in a topic Landing gear safety cables   

    Av8r3400
    Would I be able to get contact info. for your friend with the Model C Avid to find out what he went thru to get Grove gear.
    You friends swept forward gear looks like it would be what I need without having to weld on forward float fittings.
    I am curious when Grove made that gear for him because  they act like this is a new idea, not usually done and I would have to manufacture my own attach brackets.
    Thanks  Herman   Oregon   541 404 6464
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  7. herman pahls added a post in a topic Landing gear safety cables   

    Paul thanks for sharing the Yahoo messages regarding alternate bungee backups and 
    Av8r3400 with the real world Grove weight increase.
    I was told about Airdale's swept forward aluminum gear that is available for Avids that would work for a model 2 since I do not have the forward float attach points  for the grove gear like model 4's have.
    Any body have experience with the Airdale swept forward gear?
    I contacted Grove with measurements and they are working up a bid for a custom swept forward gear for my model 2.
    Grove told me they are not excited about how much forward sweep is required and will the longerons handle the the loads.
    Has any one on this forum welded on forward float attach points and the fuselage reinforcement bracing that would be required?
    My stock model 2 gear places the axle 2.5 inches forward of the forward attach point as it is.
    Herman
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  8. herman pahls added a post in a topic Avid visability   

    So where do I get an Avid cowl?
    Are there variations of the Avid cowl by year or model?
    Joey. It seems like your cowl is more abbreviated than most or is that only the front part that would normally cover the gearbox?
    Thanks Herman
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  9. herman pahls added a topic in Avidfoxflyers General Hangar   

    Landing gear safety cables
    Are the Kitfox and Avid landing Gear safety cables an asset or liability?
    When metal hits metal things bend or break.
    After 18 years of not having to weld on  my Kitfox,  I bent the bungee truss under the seat.
    The gear legs and longerons were unharmed and I was able to fly it back.
    Joey told me that he has removed the safety cables on his Avid for this very reason.
    I mention this only for other Avid and Fox owners to consider to hopefully prevent what happened to me
    I do not like flying without Safety cables even though I have not had a bungee fail.
    If going with safety cables again, I would make them as long as possible to keep the airframe out of the dirt (maybe not the prop) or how about a second set of bungees wrapped loose over the primary bungees to act as a progressive suspension and act as a safety ?
     
    TIME TO GET THE SAWZALL, TORCH, GRINDER AND WELDER OUT
     
     
    Awhile back I asked about Grove gear. Is it time for grove gear?
    Thanks Herman
     
     
     
    • 16 replies
    • 2,076 views


  10. herman pahls added a topic in Avidfoxflyers General Hangar   

    Avid visability
    It appears that the Avid top cowl is lower on the windscreen than the Kitfox top cowl piece which would give better forward visability.
    I am considering replacing my Kitfox round cowl with a smooth Avid style cowl even if it means lowering the 582 or turning it upside down Avid style.
    Does anyone have their Avid nearby to get a vertical measurement from the longeron on the bottom of the fuselage to where the cowl meets the windscreen?
    Are there any new or used Avid cowls available?
    Thanks 
    Herman
     
     
     
    • 10 replies
    • 1,332 views


  11. herman pahls added a post in a topic I am out for a while   

    I am currently viewing the Dave Ramsey "debt free" video series and am a believer.
    I wish or countries leadership was into debt free long ago so we would not be in the mess we are in.
    So I also applaud selling a toy to get debt free and therefore stress free.
    My Model 2, 582 powered Kitfox will be for sale when I find a Model 4 with a 912S.
    Herman
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  12. herman pahls added a post in a topic Grove landing gear   

    I appreciate this forums comments and experience with  the Grove style gear.
    I always wondered about the narrow fore and aft footprint where the Grove gear attaches to the brackets and the load on the longerons.
    I recently spoke with one builder of cub style-cabane gear for Kitfox's and he felt his gear needed redesign due to the load the cabane places on the longerons.
    I like the simplicity of the Grove and will consider it for my next homebuilt.
    Herman
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  13. herman pahls added a topic in Avidfoxflyers General Hangar   

    Grove landing gear
    I have been searching for a Kitfox model 4 with a 912s to replace my model 2 with a 582.
    I also want taller gear for more angle of attack
    I like the simplicity of the Grove gear but had the impression it weighed 30#'s more than the stock gear so I never considered it.
    I called Grove and they told me the their complete gear with mounting brackets for a model 4 weighs 30#'s and they could make it a few inches taller.
    So how much weight does the Grove gear really ad?
    It is expensive compared to the alternatives.
    It's design should be more aerodynamic.
    How well does it absorb landing loads, especially on rocks with ABW's compared to the stock bungee gear I am using now?
    It seems this forum has been cautious about the durability of the aftermarket "Bush Gears" so I have been looking for other options.
    How durable is the Grove Gear and how it attaches to the longerons?
    Thanks for sharing your "Gear" experiences.
    Still searching for a Kitfox model 4-1200 with a 912s.
    Thanks Herman
     
     
    • 6 replies
    • 2,550 views


  14. herman pahls added a post in a topic Grand Rapids Technology EIS 4000   

    George
    Thanks for taking the time to respond to my "disabling" issue.
    I was trying to disable 1 page at a time instead of all at once.
    After reading your post i was successful on the first try and I appreciate not having to cycle through unneeded pages to view the EGT and CHT pages.
    Do you mind sharing how you would configure your main page for a 582.
    I am curious if there is a custom configuration that would be better than what I am currently using.
    Thanks again
    Herman
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  15. herman pahls added a post in a topic Cheap Pacers   

    With a Borer Prop, 160HP, Sullivan wing tip extensions, VG's and 31" ABW's our Pacer would cruise near 100, burn 8-9 GPH and it got in and out like our folding wingers.
    Every thing we did to it made it slower and more capable if you like rocks.
    Herman
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  16. herman pahls added a topic in Avidfoxflyers General Hangar   

    Grand Rapids Technology EIS 4000
    Hello
    I have been using the GRT EIS 4000/6000  for years in my Kitfox to moniter engine vitals.
    I decided today to make better use of the EIS and install the warning light and set the operating parameters which was easy and fun to play with. 
    I wasted hours trying to disable a number of the 15 pages which I do not use.
    I googled for possible ideas on how to do this but only found complaints on how difficult the GRT EIS is to program.
    I am able to disable one page and then when I try to disable another page, the first one returns.
    I am missing something simple like what button or combination of buttons to push and when.
    When programing the GRT EIS, the user manual says the data will not enter unless you hold the "next" button till you have cycled thru the complete menu back to the operating pages.
    This did not seem to work.
     
    Any ideas out there???
     
    Thanks Herman
     
     
     
     
     
     
    • 3 replies
    • 2,817 views


  17. herman pahls added a post in a topic tailwheel spring rear support   

    Thanks Joey and Av8r3400 for replying and the advice.
    I have a 2 leaf tailwheel spring similar to Joey's but I do not have the extra hole a few inches back, so Joey's method will not work unless I order a spring like his.
    My plan is to flatten the C channel bends to make a flat plate that I can drill a hole on each side of the leaf spring for a AN-3 bolt to capture the spring with a plate on the bottom.
    Av8r3400 mentioned that I  should use a steel sleeve on each side of the leaf spring to prevent squeezing the leafs and causing them to bind. 
    I found a drawing on line showing the Kitfox Super Sport tailwheel spring installation, using steel sleeves.
    What is interesting is that our much heavier Pacer had one -4 bolt on each side  capturing the spring without sleeves.
    I tried bending the .070 cold without success and then used acetylene torch which worked well and thankfully did burn  the nearby fabric.
    I realize ground looping is an ever present risk especially since my tailwheel is not connected to the rudder and if the brakes were to fail.
    When I land, especially on short rough strips the tailwheel does not touch till I have virtually no forward speed.
    I appreciate the concern.
    Herman
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  18. herman pahls added a topic in Avidfoxflyers General Hangar   

    tailwheel spring rear support
    My model 2 Kitfox tailwheel leaf spring is bolted in the front and semi captured in the rear by a C channel and not captured by vertical bolts and a strap on the bottom like I have seen on Model 4 Kitfox's and our Pacer.
    Since I started flying on rocks I have removed the steering springs and modified the tailwheel to freely swivel so the tailwheel would not give feedback to the rudder.
    My worst fear was a tailwheel leaf spring failure that would put pressure on the rudder that could not be overcome inflight.
    My worst fear was realized yesterday when the leaf spring popped out of the channel and it was a none event because I was pushing it into the hanger when it happened.
    Even with the steering springs removed, this could have caused a ground loop if I was moving at speed with the tailwheel on the ground.
    I mention this since I assume my Kitfox was not the only Kitfox or Avid that came this way.
    I plan to weld on some tabs to use bolts to capture the spring.
    Anybody done this to share how they solved this issue?
    I am concerned about welding right next to the fabric.
    Thanks Herman
    • 28 replies
    • 4,863 views


  19. herman pahls added a post in a topic Cost Per Hour   

    Having a fuel flow  indicator will go a long ways towards reducing your gallons per hour..
    It is amazing how much fuel the 582 can burn at or near full throttle.
    That last 10 MPH may cost you several GPH.
    The HACman reduces the fuel flow by allowing you to raise your EGT's at most power settings to 1150 degrees, or what ever temperature you are comfortable with.
    Herman
     
     
     
     
     
     
     
     
     
     
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  20. herman pahls added a post in a topic AK 670 Powered Kitfox on Barnstormers   

    The general aviation airplanes I have flown from 150's to Bonanza's, it seems Lycomings and Continentals burn about 5-6 gallons/100 horsepower.
    I am sure the 2 strokes will also burn according to power output with no magical fuel savings with a certain engines including the 670.
    Inflight Adjust Props and mixture control are the only way I have found to maximize take off, cruise performance and fuel burn on 2 strokes.
    I want 100 MPH at 5 GPH on 29 inch ABW in my Kitfox which probably is not possible with a 2 stroke.
    If money and weight and balance were not a problem, we would all be flying 912's for maximum power/fuel burn/weight.
    Herman
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  21. herman pahls added a post in a topic Kitfox landing gear flex   

    I would post a short video of my Kitfox on 29's if someone can tell me how to do it simply.q
    I am a way from home for several days so I would need to do this from an iPhone.
    I think I know how to fly but am clueless as how to post photos or videos on forums.
    Herman
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  22. herman pahls added a topic in Avidfoxflyers General Hangar   

    Kitfox landing gear flex
    It has been observed that my Model 2 Kitfox landing gear must be flexing when I am braking for as short of roll out as possible.
    It was noticed  that when braking that the normally tight fabric covering on the gear is wrinkled and that the gear is towed out.
    I use 29" Airstreaks and the brakes are capable of easily nosing the airplane over.
    I am sure the size of these tires is placing more leverage on the gear than originally intended.
    My first thought is to remove the covering, which I have seen on many Backcountry airplanes so I can watch for cracks.
    Should I be concerned about this flexing considering that my wings flex all the time especially in turbulence?
    Should I remove the fabric to watch for cracking?
     
    Thanks for the advice.
    Herman
     
    • 5 replies
    • 830 views


  23. herman pahls added a post in a topic Coolant expansion tank mounting   

    My Murle Williams aluminum radiator is bolted flush with the fuselage bottom on my Model 2 without any scoop or fairing.
    Most I ever see is 165 degrees at sea level on the southern Oregon coast with the 582 thermostadt installed.
    Herman
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  24. herman pahls added a post in a topic incremental flaperon control lever for my Model 2 Kitfox.   

    Randy and Robert
    Thanks for posting photos of your incremental flap actuators.
    Gives me a good idea how to get started without re inventing the wheel.
    I also appreciate the comments on how Avid and Fox owners use their flapperons.
    Thanks Herman
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  25. herman pahls added a post in a topic incremental flaperon control lever for my Model 2 Kitfox.   

    Joey
    So is the bottom line with flaperons on these Avid's and Fox's is that they are most useful to break ground ASAP on take off?
    Otherwise they have minimal effect in comparison to say normal flaps on a Just Highlander ?
    What part of the world are you in?
    Herman
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