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RFguy

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Everything posted by RFguy

  1. RFguy
    Tyabb - Cowra - Moree - Caboolture ?
  2. RFguy
    Not sure how that all happened at BRM. Seems a rookie mistake having a airplane get into production and then to need to add that mass....
  3. RFguy
    skip, you said : "taking into account the afromention effect on spin characteristics.." and just how are you going to "take into account the effort on spin characteristics" ? Going to go off and do this with a airframe parachute etc ? Start sweating when she doesnt recover from a developed spin when you are down to 3000' ? I'm not being flippant, just being real about effects and consequences ....
  4. RFguy
    I've now read the rest of this thread I would STRONGLY advise not adding weight to the tail ! (to get CG in right place) . no way. You will affect spin recovery / stall behaviour. Do what you need to do to maintain the original CG location. add or subract or move weight within a meter of the CG location ...... This may require the result to be that the outcome is heavier than original. IE sure you can put 1kg in the tail instead of 4kg behind the pilot. BUT you will change the dynamic stability of the airplane, and affect stall/spin recovery, things your aircraft was tested to . IE you are making a different aircraft and it in my mind would no longer meet the specifications of the certificate it holds.
  5. RFguy
    I'd think that you'd want it as fixed equipment.
  6. RFguy
    updated my post
  7. RFguy
    For easy weighing for LSA, during rotax install, I bought three of these floor industrial scales. (not RAAus approved but accurate) https://www.ebay.com.au/itm/285144918758 A fairly inexpensive investment for one wanting to engage in modifications that affect the CG location.. For a 912ULS in a J160, I'd expect something would need to be moved to the baggage..... Ideally any mods should result in a CG that is in the same location and little change to the moment of inertia around the CG location . in order to satisfy the pub test.... Beware though that adding ballast to the rear , for example, I would not recommend as it may change spin recovery behaviour (because it increases the moment of inertia). If the rotax whole kit weighs more (likely for the 2200) , I would expect it likely you'd need to add weight in the baggage- and the likely best way to do that is move the lead-acid battery to the bags. I have seen some Oil cans moved to the rear and I would be careful with that because it will require UPSIZING of the suction side hose for the long length. (which was not done in one I saw) ....
  8. RFguy
    In the US , it is not 'imperial'. it is "US or British " units (but then there is the british gallon and US gallon) . As for sportpilot- they should use what is recnognized by our regulator for aviation, which is non metric units, except for visibility and RWY length . (which is wierd ) . Glen. (am also a US citizen) .
  9. RFguy
    Let's see here. specs. empty 985lbs(447kg) with Titan340 . mmmm I'd want a 140 hp engine for that plane with those numbers and role. So a 915 is an excellent choice I think, Mark. But 914 too small. 916 is unnecessary. The weight (447kg empty ) would be only 400 kg empty with a rotax, so even 130hp would be good. Mike, according to the datasheet, the conty in MOGAS compatible format (you'd surely want that) is 8:1 and 174 hp. I am sure any issues with the CG / aft load etc could be solved with the 915 by moving sh1t around. ....-glen.
  10. RFguy
    yeah I was in suboptimal shoes also (Volleys) . my feet killed at the end of each 14 hour day on my feet even with silicone insoles.
  11. RFguy
    I'd reckon rotax would dot their i z and cross their t z, I'd have no concern with buying a 916 if I could spend that sort of money. (But then I'd buy an IO-360 instead of a 916) Remember- Maximum continuous power is 137hp for a 916. 160hp is takeoff power, and short term climb power. 200hp IO360 can do 200 hp all day if you keep the CHTs down...... and does not have any complex electronics nor water At altitude, the Lycoming will still make good. I reckon usual story for turbo if you consistently operate hot and high, then the turbo engine is for you (or buy a slightly larger Lycoming an IO-390 ) 8.5:1 IO360 can run MOGAS. not sure about 8.7:1 version (check) . dont think 8.9:1 '390 can. I like having the extra HP in my bird so that I can still put out good speed/power even when leaned extreme (65-70%) . Gearbox is nice on the rotax though- low speed prop- more efficient slightly, AND not same issue if you have a prop strike.... Might have to think about weight though.... not having the boat anchor up front will change things. Wonder if the 916 will have a oil thermostat as standard- they SHOULD have IMO. (for fast warmup and stabilized, correct oil temp)
  12. RFguy
    Putting aside spark plugs connections (I dont think that's the problem) ---I'd ensure all the plug in connectors in ALL the harnesses and plug in sensors are well seated and fixed down so they cannot free vibrate. You might cycle the harness and sensor connectors and inspect terminals under light and magnification . Of course, I am guessing, but this would be my immediate checks
  13. RFguy
    maybe some issue with a combination of higher vibration (low RPM) and less than perfect crimped connectors. someone must know at factory.
  14. RFguy
    Howdy I've heard of this from an aircraft on the sunshine coast. cant remember which.. I would be sure rotax have a diagnostic log in their box. This will contain the info.... Many engine shops, not sure about Berts, are generally low tech affairs and shy away from this data.... Talk to the factory . is this at low idle or moderate power ? gather in a flare so it is occurring at idle stop ? - glen
  15. RFguy
    Mark, BTW according to Mr Factory Rotax (at the show) , while 912, 914, 915 are similar beasts, 916 is new crankcase, new gearbox, new turbo. .....also, old turbo in 914 is no longer available. Has your S21 got the big bore 912ULS in it at 10.5:1 ?
  16. RFguy
    How about gearbox compatibility ?
  17. RFguy
    For those wanting a different wing, a wing change would require a lot of engineering and test. I think the existing wing is fine. If you want a shorter landing airplane, just get the drag up. there is a way to do this. (apart from ensuring your idle speed is lowest possible/safe) Jabiru actually reduced the flap max deflection in its aircraft 2007 ish because it was found that it didnt provide anymore lift, just more drag, and that it wouldnt climb in a go around terribly well at max flap.... I think that extra drag is definitely useful to reduce landing distances, and will modify my aircraft I think (move the flap motor stops ) . Sure it wont climb easily in a go around at the max flap , but neither will my part91 certified aircraft. I know another owner that used the extra available unused motor travel to reflex the flaps, for slightly higher cruise speed.... but it turns out the most drag at cruise is not the wing but the nose and the gaps and the mains. -glen
  18. RFguy
    Well , deadly silence from Jabiru upon the question this morning amongst other correspondance. Must be true. Maybe I will keep my J230 and finish the rotax conversion. (need to do a customized exhaust system, or just use straight pipes out the side) . Maybe inject some avgas into the outlet pipes for effect instead of the strobes.
  19. RFguy
    Today, in email conversation with Jabiru regarding current engine delivery (about 9 months for a Gen 4 3300 is the answer) I have asked the question about the company sale.... No response, so far. We'll see.
  20. RFguy
    The air is different in Europe, the air they breath and fly in is denser by being subsidised as extra 0.3kg per cubic meter by taxpayers , leading to a lack of world competetiveness, and aircraft that can only meet their specifications in european air.
  21. RFguy
    Hi Mark I see some aircraft have BRS fitted behind the instrument panel.... Is the S21 Conty mount just for a generic continental, or is there something specific about a Titan 340cu" ?
  22. RFguy
    I might add on the Va thing, while its accepted Va can calculated by taking the clean stall speed multiplied by the squareroot of the load factor, In the example I used above of the ATEC, that was the designed load factor (3.8g normal category ). HOWEVER If the aircraft did not break say until 8g, then the designer might use that value in the calculation of Va (but the FAA might not like it) . In the book , Faeta NG is given at 600kg, Vs1 of 40 kts. and 4G limit. which implies a Va of sqrt(4) * 40 = 80 kts. If the aircraft didnt actually fail until say, 8G, the mfr might write down 113 kts. That might be OK for LSA, but for a Part 91 aircraft , the FAA wouldnt accept that (is my reading).
  23. RFguy
    I imagine they'll move prop maybe forward, battery forward , oil tank fwd etc etc all the usual. The TAS is good, Mark. 10,000'. Well like I always say, if you fly low you are leaving TAS on the table. (said from a cross country flyer's perspective). Mike when are you back in Australia ? Stuart and I will make a trip to see you. cheers,
  24. RFguy
    yeah 915 is better because there is a turbocharger there.... but hard to go past an O320, surely ??? (or was it a 235 you were looking at ? ) what about CG Mark- do they need to move the propellor location forward to get the same CG range ? (IE without that paperweight Lyco-conty on the front) ? or is the paperweight actually too heavy (or suboptimal) for it ?
  25. RFguy
    I expect they would sell a ton of J230 airframes with a 3 blade 912ULS in them. and 914/915 as a upmarket option. although these days, there are many composite competitors snapping at their heels. It's not a complete shoe-in. assuming same thrustline and prop location (as I had), cowling needs to be bulged a bit on front lower to accomodate the exhaust headers from the front two cylinders.. not too much work really.
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