Loading ...
Sorry, an error occurred while loading the content.

Re: [CriCri] Slow flight specs?

Expand Messages
  • W. David Doiron
    In , on 04/26/02 ... One must remember that flaps have ONE main purpose: They reduce the
    Message 1 of 7 , Jun 4, 2002
    • 0 Attachment
      In <49161BD15CC4D311B78400C04F109D3A01004E00@...-can.com>,
      on 04/26/02
      at 10:20 AM, "Wiebe, Alex" <awiebe@...> said:


      >The AMT jet modification apparently consumes fuel pretty quickly.
      >- how well (or how long) does the Cri-Cri hold up when
      >lose complete power?

      >To acheive max glide, what are the recommended flap settings and airspeed
      >At this configuration what is the Cri-Cri's glide ratio and vertical
      >speed in fpm?

      One must remember that flaps have ONE main purpose:
      They reduce the landing speed.
      In order to do that, it costs DRAG. So if you are trying to extend the
      glide in ANY airplane, would you want to add drag?...
      You would probably want to extend flaps on SHORT final when landing is
      assured just to reduce the landing speed (and in turn the landing
      distance). Yes I know every student pilot is taught to use flaps for a
      power-off practice landing, but remember that is with the engine
      SIMULATED dead. It is still available just in case... I watched Howard
      Josephson crash short of Falcon Field in his CriCri when both of his
      engines died and he insisted on extending flaps right away. As a result he
      did not make it to the runway. As a testament to the strength of the
      CriCri, He was not hurt, and the airplane was repairable, but he could
      have made it to the runway if he had left the flaps retracted...I know
      because I was flying formation with him in my CriCri, and with my flaps
      retracted and throttles at idle (windmilling props), I landed 2000 feet
      beyond where he crashed...
      Max glide would be different for each individual airplane. You would have
      to do testing of the individual airplane to determine your own numbers.
      Mine seemed to be happiest at about 80 mph.
      I'm sorry I cannot remember what the rate of sink was, but it seems like
      it was less than 2000 fpm. I only had 1 dead stick landing, and I was
      concentrating on making it to the runway!

      >As well, a typical twin engine must has a requirement that once it
      >reaches a certain speed, it must be able to take off with only one
      >engine. Is the Cri-Cri capable of taking off with only one engine? and if
      >so what is the decision speed?

      In a word, NO! The JPX is not capable of sustaining level flight with only
      1 engine running, so it certainly cannot climb. Anytime a JPX fails you
      are in the landing mode. The Limbach (2-cyl) has about 4 hp more than the
      JPX, and the CriCri will just BARELY climb on one, but since the landing
      distance is so short, I would probably land even if I was already
      airborne as long as there was a good length of runway remaining. By the
      way, the key to the short landing distance is DISC BRAKES...

      Also, just for general information, my CriCri was capable of slow flight
      of less than 40 mph, but it would NOT take off at less than 60 to 65 mph!
      (depending on weight) !! It seems that the airflow would not "stick" to
      the wings on takeoff until it got UP to 60 or so, but once it was "stuck"
      it would stay there down to stall speed. BEWARE, under certain conditions
      of intentional slow flight, one wing may stall while the other continues
      flying. You will get a snap spin entry, which is a prohibited maneuver in
      CriCri. And if it happens close to the ground, there is no room for
      recovery.

      Amicalment,
      --
      -----------------------------------------------------------
      W. David DOIRON <DDoiron@...
      -----------------------------------------------------------
    • Wiebe, Alex
      Thanks for the excellent information, unfortunately with any good information comes more questions. Hopefully you have the patience. Is the Cri-Cri classified
      Message 2 of 7 , Jun 4, 2002
      • 0 Attachment
        RE: Slow flight specs?

        Thanks for the excellent information, unfortunately with any good information comes more questions. Hopefully you have the patience.

        Is the Cri-Cri classified as a twin engine in North America? it must have some special designation if it cannot continue a take off roll / climb on only one engine.

        So what you're saying is that if you loose your engines (run out of fuel for example) you probably have at best just a minute or 2 to find a parking spot. What would the min. sink rate be for the Cri-Cri?

        Many people comment on how safe the Cri-Cri is under normal circumstances, I'm trying to understand it's disaster recovery capabilities.

        BTW, your experience with slow flight vs min take off speed is extremely counter-intuitive. I would have thought that ground effect would provide more lift at slow speeds allowing you to at least get the wheels off the ground at speeds less then those required to maintain altitude above a few hundred feet. Any one else verify this anomaly?


      • graheme@xtra.co.nz
        Hi guys, Thought I d jump into this one, as it is right up my alley, so to speak. Better intro myself first. I m Graham Allan, and I m just starting to build 2
        Message 3 of 7 , Jun 4, 2002
        • 0 Attachment
          RE: Slow flight specs?

          Thanks for the excellent information, unfortunately with any good information comes more questions. Hopefully you have the patience.

          Is the Cri-Cri classified as a twin engine in North America? it must have some special designation if it cannot continue a take off roll / climb on only one engine.

          So what you're saying is that if you loose your engines (run out of fuel for example) you probably have at best just a minute or 2 to find a parking spot. What would the min. sink rate be for the Cri-Cri?

          Many people comment on how safe the Cri-Cri is under normal circumstances, I'm trying to understand it's disaster recovery capabilities.

          BTW, your experience with slow flight vs min take off speed is extremely counter-intuitive. I would have thought that ground effect would provide more lift at slow speeds allowing you to at least get the wheels off the ground at speeds less then those required to maintain altitude above a few hundred feet. Any one else verify this anomaly?



          Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
        • Danny Creech
          ... I take it that your saying you take off without flaps and you slow flight at 40 mph without flaps right? I just want to make sure we are talking apples and
          Message 4 of 7 , Jun 4, 2002
          • 0 Attachment
            > Also, just for general information, my CriCri was capable of slow
            > flight of less than 40 mph, but it would NOT take off at less than
            > 60 to 65mph!

            I take it that your saying you take off without flaps and you slow
            flight at 40 mph without flaps right? I just want to make sure we are
            talking apples and apples and not apples with oranges. So to speek. ;-)

            Danny Creech
            WISHING he has a Cri Cri
            ^^ Can never find one for sale.

            __________________________________________________
            Do You Yahoo!?
            Yahoo! - Official partner of 2002 FIFA World Cup
            http://fifaworldcup.yahoo.com
          • Danny Creech
            ... Yes, after all it has two engines right? hehehe ... It s called Expermintal. That means it s at your own risk. If you want to build a box and make it fly
            Message 5 of 7 , Jun 4, 2002
            • 0 Attachment
              > Is the Cri-Cri classified as a twin engine in North America?

              Yes, after all it has two engines right? hehehe

              > it must have
              > some special designation if it cannot continue a take off roll /
              > climb on only one engine.

              It's called Expermintal. That means it's at your own risk. If you want
              to build a box and make it fly the FAA will let you do it. Of course
              there is that 25 hours of flight time thing. Remember, the Expermintal
              area means you can build anything you want. Look at the spruce goose.
              That never did get out of ground effect.


              Danny


              __________________________________________________
              Do You Yahoo!?
              Yahoo! - Official partner of 2002 FIFA World Cup
              http://fifaworldcup.yahoo.com
            • W. David Doiron
              In , on 06/04/02 ... David ... Good point, Takeoff was with 1 notch of flaps-- slow flight was with full
              Message 6 of 7 , Jun 5, 2002
              • 0 Attachment
                In <20020605060146.68582.qmail@...>, on 06/04/02
                at 11:01 PM, Danny Creech <dannycreech@...> said:

                >> Also, just for general information, my CriCri was capable of slow
                >> flight of less than 40 mph, but it would NOT take off at less than
                >> 60 to 65mph!
                David

                >I take it that your saying you take off without flaps and you slow flight
                >at 40 mph without flaps right? I just want to make sure we are talking
                >apples and apples and not apples with oranges. So to speek. ;-)
                >Danny Creech

                Good point, Takeoff was with 1 notch of flaps-- slow flight was with full
                flaps. But my point remains:
                For any given flap setting, CriCri takes more speed to start flying than
                it does to continue flying.
                -----------------------------------------------------------
                W. David DOIRON <DDoiron@...
                -----------------------------------------------------------
              Your message has been successfully submitted and would be delivered to recipients shortly.