nlappos

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Everything posted by nlappos

  1. nlappos added a post in a topic evolution of the old avid Catalina   

    Like the Flyer, the Catalina is a testament to a great Dean Wilson design.
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  2. nlappos added a post in a topic evolution of the old avid Catalina   

    About $400,000.
     
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  3. nlappos added a post in a topic Bush gear failures   

    I just bought the gear from Lowell a few days ago. We exchanged emails about it and he knows it works, and that it is strong, but how can he control folks who land off site?  As I said above the gear is quite strong enough for landings at 8 to 10 feet per second. As an indicator of how hard that is, the max landing at 8 feet per second is a 4 G landing while not damaging the gear. In a UH-1 helicopter, 8 feet per second (480 feet per minute) will spread the skids and make the belly touch the ground. 
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  4. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    Marcus
    The angles I used are the actual ones, the upper rod is 58.5 degrees from the ground, and the lower one is 32.3. The sketch I drew is not to scale, it is for identification of the terms used. Here the dimensions and angles are correct, the drawing is just a cartoon, don't use it, just its numbers. The spring is correctly sized, the gear meets Part 23 requirements for a 8 feet per fecond drop, and the spring does not bottom on that drop, it can go to almost 4 g's before it bottoms.
     

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  5. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    I did an analysis of the Fitt Cabane gear that I have and the numbers all look good, as does the sizing of the coil spring. Let me post them for you all to shoot holes in them (and the way I analyzed it).
     

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  6. nlappos added a post in a topic Bush gear failures   

    Here is a full analysis of the Lowell Fitt gear. It shows that the spring is not too stiff, it is sized just right for the design conditions (8 feet per second drop at gross weight) and it does not go solid until you exceed that drop and get about 4 G's on impact. Note too that he has addad a cross bar across the top of the Cabane strut so the two aircraft sides now have additional bracing from the side forces the gear puts on them as it shoves the longeron inward.


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  7. nlappos added a post in a topic Remote control outlet   

    akflyer knows his stuff!
    https://www.amazon.com/KiaoTime-GSM-AUTO-DC-US4G-Output-Control-Contact/dp/B01N5LGJLA/ref=sr_1_cc_1?s=aps&ie=UTF8&qid=1519092278&sr=1-1-catcorr&keywords=GSM+4G+remote+switch
    First user comment on the page: "Using it to turn on a heater in airplane hangar. Turns on and off immediately on phone call, and sends a confirming message within a few seconds that I have programmed to tell me that the heater has been turned on, or off. I was also able to program it so it will only react to phone numbers I have pre-authorized. I had to connect it to a relay that will switch the current required for the heater."
     
    I swapped to a better listing, akflyer is right, must make sure the device is at least 3G, (the listed unit is 4G) because the cheaper 2G units are being dumped in the US for low prices, and the ATT cell network won't talk to them.
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  8. nlappos added a post in a topic Bush gear failures   

    This is a great conversation! To add fuel to the fire, here is a sketch I found that supposedly matches the J3 gear, it is also the EAA Biplane cabane gear.
    Please note that the dimensions are quite close to the gear I am installing, any differences are due to the Avid's much wider side by side fuselage.
     
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  9. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    No computers were harmed in the making of this movie. All hand calculated! Notice the cabane has a cross bar at the top to reinforce the fuselage from the side forces of the upper strut. In any case, these loads look a lot like the same from the original bungee system, frankly. The biggest problem is that we have to eventually hit the ground I think.
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  10. nlappos added a post in a topic Uncoordinated Stall   

    Zadwit, your advice is good, but for a slightly different reason.
    Abuse of the rudder is the biggest single cause of low altitude turn problems. The difference in speed of each wing in an extreme turn is not enough to cause a stall. For an extreme turn, here are the numbers:
    speed 60 mph, Bank angle 45 degrees, turn radius 241 feet, Speed of inside wing mid span 58 mph, tip 56 mph, Speed of outside wing mid span 62 mph, tip 64 mph (for a 30 foot wingspan)
    Having instructed lots of folks, I have found that abusing the rudder causes skidding that makes the aircraft bank severely into the turn, and washes out the aileron control rapidly. Opposite rudder is clearly needed, but not because of stall, because that is what you are doing wrong, too much bottom rudder.
    If you find yourself losing roll control in a steep slow turn, check ball. Add full power. Reduce back pressure and use top rudder as needed to make sure ball is centered, roll out and start a climb.
    Here is a turn calculator that can help you see the physics: http://www.csgnetwork.com/aircraftturninfocalc.html
     
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  11. nlappos added a post in a topic New Rotax 670 Install   

    The reality is I swapped my 350 hour 582 for the zero time 670 at $3550 price. To overhaul my 582 it would be $3000 at most shops, $2200 with Rick. So I reasoned that the 670 cost be $1350 more than my 582.
    the Simonini Victor is $9550, and I bet it’s a fine engine.
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  12. nlappos added a post in a topic New Rotax 670 Install   

    Got the engine hung on the mounts. Used a Harbor Freight hydraulic table to lift it and roll it in. Next will tie up all connections and start fitting the muffler and exhaust (custom made by Mike Hair).
    for the record, the old 582 thick aluminum saddle mount brackets fit perfectly. ”Rick” had trimmed the block in a few places so clearance was not a problem.

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  13. nlappos added a post in a topic New Rotax 670 Install   

    Mike Hair did my exhaust. Nice guy.
    How many hours do you have on the 670?
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  14. nlappos added a post in a topic New Rotax 670 Install   

    Ron Davis asks for pre-mix as a warrenty term, so I am pre-mixing at 40:1
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  15. nlappos added a topic in Rotax and other engines   

    New Rotax 670 Install
    I unboxed my 670 today and started the install. I will use this thread to report 670 specific item for the group
    Rod Davis, Rotax Rick zero time engine. Job looks great, high quality, neatly packed, all accessories and hardware. 
    Mounting- standard Avid 582 brackets fit properly. Looks like it will slide in easily. Details to follow.
    Weighed everything:
    670 engine 89.5 lbs
    Starter and housing plate 5.5 lb
    Bing 54 carbs 4.0 lb (2carbs)
    Dual air filter and clamps  1.0 lb
    total 100.0 lbs

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  16. nlappos added a post in a topic Icom A-5 Error message   

    Full reset? Here is from the Icom site. No A5 shown, but maybe one method will work. GL!

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  17. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    Ed,
    I will check the spring rate on the ones I have as a start. Meanwhile, any advice from the Guys Who Have Already Been There?
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  18. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    What would you recommend instead, EDMO?
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  19. nlappos added a post in a topic Leaning the carbs for altitude - on the cheap   

    I have a HACMAN on my 582, and it works well. It has enough authority to lean at least 1.5 GPH at altitude (from almost 6 GPM to about 4 or 4.5), and would raise the EGT from 800 to about 950 or 1000 degrees. Using the HACMAN always seems to prevent any rich plugs. I flew across the US from Stockton CA to New Haven CT, across Wyoming, so I got to see all types of altitudes from SL to about 11K', and I could always lean to keep the plugs clean.
    The HACMAN principle is simple - it has a screw valve in the cockpit that drops the carb bowl pressure by mixing some of the very low pressure area at the carb throat (the air at the throat has low pressure because the air in the throat is flowing so fast.)  The low pressure from the carb throat reduces the bowl pressure so less gas is sucked up into the throat, the HACMAN lets you  lower the pressure differential between the bowl and the throat.   It basically reduces the suction so the needle valve lets less gas into the carb, thus leaning it out. (This really just restating what Turbo wrote above, his sense of the physics is spot on).
    Frankly, the HACMAN is just an air needle valve and some cheap hoses, my guess is we could make one fairly easily, but since I was flying over the Rockies and didn't want to walk home, I paid the money.
    The altitude compensating HAC that Rotax sold at one time appears just like the HACMAN except it used a simple diaphragm to adjust the mixing of the two air sources. 
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  20. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    FoxDB
    Sharp eyes! That’s the old 582 Y pipe I was matching for size. The short fat 670 Y pipe is coming from EBay soon.
    Any thoughts on EGT?
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  21. nlappos added a post in a topic Avid Flyer Mk IV Major Change and Upgrade   

    Ok lined up all the major items for the refit of my Avid. New Rotax 670, new Warp Drive prop (cut and tapered), new Fitt Cabane Gear, and new matched exhaust system. Tomorrow starts the wrench turning!




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  22. nlappos added a post in a topic Who’s experimented with spinners?   

    Joey,
    My guess is the big vs little spinner makes no difference on a very draggy strutted aircraft like ours. Best way to tell is fly it without any spinner, and then with the big one and take a few careful identical performance points. The small spinner is clearly better than none, and it the difference between none and big is a slight diff, that proves the case.
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  23. nlappos added a post in a topic Engine Failure yesterday   

    I am a "closed vent" guy. My vent is a short one with a valve, and stays closed in flight. I open it on preflight and watch fuel pee out to assure that the header has no air. This design has successfully flown for about 700 hours over 22 years without a problem.
    BTW I think Fred has a pretty good handle on what happened here.
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  24. nlappos added a post in a topic Avid Flyer Nose Dragger wheel shimmy?   

    Refresh me, what’s the stall speed of a speedwing?
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  25. nlappos added a post in a topic Avid Flyer Nose Dragger wheel shimmy?   

    certainly not balance, the wheel twists violently. Only one steering rod, to the right side. Damper is a good idea, anyone try one?
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