New builder with questions about insturments

Discussion in 'Instruments / Avionics / Electrical System' started by benny, Jun 16, 2006.

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  1. Jun 16, 2006 #1

    benny

    benny

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    Hello Everyone,

    Ben Ramler up here in St. Cloud, Minnesota. i was wondering if I can ask a question about instruments. My question is this; I am about ready to build a LM-J3-W which is 100% scale replica of a Piper cub from Light Miniature Aircraft. What I was wondering is this should I be concerend about having a transponder in my airplane when its done? If the question is Will flying in a Class B airspace I really don't know. The St. Cloud Airport here in central minnesota just put up a tower so its a class D airsapce.

    thanks,

    Ben Ramler
     
  2. Jun 16, 2006 #2

    Rhino

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  3. Jun 17, 2006 #3

    benny

    benny

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    Yes I understand and know that already. did you understand at all what I was trying to say? If not I can clarify.


    Ben
     
  4. Jun 17, 2006 #4

    Chairboy

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    The important question is "Where will YOU be flying?"

    There's a Mode C veil around every Class-B airspace, usually 30 miles radius from the airport to which the Class-B is attached. If you expect to fly within 30 miles of a Class-B airport, then you'll need to have a Mode C transponder.

    Are you building an electric system into your plane? If so, you can pick up a transponder on eBay or from barnstormers for cheap. If not, then I understand your hesitation.

    Good luck, and remember the mode C veil!
     
  5. Jun 18, 2006 #5

    benny

    benny

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    Hi Chairboy,

    Hows your weekend? Anyways, I really don't know if I will be flying into it. Here Central Minnesota the St. Cloud Airport just built a tower about 2 years ago or so and the airspace changed from E to D. i checked the FARS and it says nothing about needing a transponder in a D airspace. As far electrical system I really don't know. On one hand at least i can put a starter instead of hand propping it. on the other hand it would at wait! So I don't know. I would really try to avoid class B. The only I would want to fly down there is maybe for a Fly-in breakfast maybe I guess.

    I'm not sure how to answer it to be honest with you!


    Take Care!

    Ben Ramler
     
  6. Jun 18, 2006 #6

    wally

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    Hi,
    Here is my take on the transponder requirement.

    If the experimental airplane does not have an "electrical system" by that they mean a charging system for the battery, then you do not need a thing. For production airplanes, if it was originally built without an electrical system, they are exempt also, like the J-3 cub, etc. However you are NOT allowed into Bravo airspace without special permission or reason like to get to an airport for maintenance.

    I do fly under the MEM class B with my mode C transponder equiped Cessna. But my Pitts will not have anything in the way of electrics except for a battery to start it, at least for a while. I do plan on eventually adding a Micro-aire radio and transponder when I recover from the huge money drain of building it.

    You can actually fly into just a class D towered airport with no radio if you coordinate with the towere by phone first. A transponder is only needed at Class C airports

    A local instructor and student has a generator fail on a training flight. They landed at the little grass strip I have my planes at. He wanted to get back to the class D towered airport about 15 miles away where he was based. So he called the tower, told them what he would like to do and they gave him the winds and active runway. They told him to fly the pattern and watch for the green light. I propped them and away they went. (a real scary job hand propping a 180 hp Cessna)

    There are several experimental planes flying like that near here.
    Good luck,
     
  7. Jun 18, 2006 #7

    benny

    benny

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    Nice story walley,

    so Just so I understand what you are saying here........you are saying that first off a transponder is NOT needed in Class D airspaces. As for an electrical system if I really don't need one unless I need a charging system. Am I right so far or no?

    thanks,

    Ben Ramler
     
  8. Jun 19, 2006 #8

    wally

    wally

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    Yes and Yes.

    If the class D airport is under the 30mile veil of a class B airport then certificated planes still need mode C transponders even though they do not ever enter the Class B airspace. Experimental planes with only a radio can go to and from the towered airport. In this case, near a Class B airspace, a mode C transponder (altitude reporting) would be a very good idea tho. Center sometimes sends a big plane along the bottom of their airspace. Say the bottom is 3000FT, there could be a DC-10 cooking along at 250 kts at that exact altitude. And sometimes they do especially at MEM! You would be "legal" at 2950 but not too bright.

    If the Class D airport is out by itself, then all you need is to establish radio communication with the tower to enter their airspace.

    For Experimental airplanes if you do not have an electrical "system" (charger) then you do not need a transponder or radio. But you do have some limits where you can go.

    You will not be able to operate at the class D airport very easily if you don't have a radio. You need to call the tower on the phone before entering or leaving their airspace.

    At uncontrolled airports, no problem, just see and avoid, fly the published pattern at the correct altitude and enjoy.

    As an aside, be very aware of any controlled airspaces, there are some very big and fast planes operation in and near - it could ruin your day.
    Wally
     
  9. Jun 22, 2006 #9

    Peter V

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    The latest transponders only need half an amp to run, so you don't need a charging system to run it. A small motorcycle battery (less than half the size and weight of a car battery) will give you 20 - 30 Amp hours, so you should get plenty of hours of flying time.

    You just get the inconvenience of taking the battery home at the end of the day to charge.

    But it's one less parasitic system on your engine.:D
     
  10. Jul 19, 2006 #10

    IanJ

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    Just real quick, speaking as a motorcycle guy, most motorcycles these days run 6-12 Ah batteries. That's not to say you can't find excellent, tiny 20-30 Ah batteries out there, but widen your search to include lawn tractor batteries and other small 12V systems.

    Also always keep in mind that a standard lead-acid battery should never be drained beyond 80% capacity (meaning if you get a 20 Ah battery, plan on only ever using 4 Ah of it). Deep cycle batteries can go down to 50% or so. If you drain a lead-acid battery all the way, you'll kill it in short order.
     
  11. Jul 19, 2006 #11

    Peter V

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    Well how am I going to power the airhorn on my Moto Guzzi with a 12 Ah battery? :pout: :D

    But seriously, take a look at computer UPS batteries for the best bang for the buck.
    The one I'm looking at right now (my doorstop!) is about the size of three video cassettes and rated for 18 Ah.

    UPS batteries are a very competitive area, so the prices are rock bottom.
     
  12. Jul 19, 2006 #12

    IanJ

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    Very true! Fry's has numerous gell cells with quite good Ah ratings for very low prices. The 80% rule still applies, though.

    And, Peter, of course I was not referring to older Guzzis (coming from older BMWs myself, so I'm well aware of the high Ah batteries -- I'm just saying that the most commonly available m/c batteries are smaller and lower rated).

    I think you'd be hard pressed to find more than a 15Ah battery without looking to the Goldwings or something, but I'll admit I haven't studied the area of motorcycle batteries exhaustively. :D

    My new Ninja 250 now uses a 6 Ah vs. the 9 Ah the 2001 model came with. Uh, go Kawasaki? Way to cheap out! Hooray!
     
  13. Jul 19, 2006 #13

    Peter V

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    Ouch! you wouldn't want to crank that thing over too many times on a cold morning! :(

    So by 2030 the Ninja 250 will be powered by a couple of these?
    [​IMG] :gig: :gig:
     
  14. Jul 19, 2006 #14

    IanJ

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    Pretty much. By 2015, I'm pretty sure the Ninja 250 will have either been eliminated, or replaced by something with fuel injection and a catalytic converter. I have no idea how the electrical requirements would change.

    It is kind of funny to pull out that little battery and heft it. Then, of course, you notice the rubber boot they stuck in there to take up the space where a 9 Ah used to be. At least I can go back to the bigger battery when this one croaks.
     
  15. Jul 21, 2006 #15

    Rhino

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    I understand. I was just trying to clarify. If you're going to have an electrical system, I'd go with a transponder just to be safe. If not, then maybe one of the above suggestions will work for you. Keep in mind though, that many people build or purchase an aircraft with a specific purpose in mind, only to find that purpose expanding well beyond the original intention, and in short order. I say keep your options open to the maximum extent possible.
     

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