twin engine light sport plans?

Discussion in 'General Experimental Aviation Questions' started by death31313, May 8, 2010.

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  1. Aug 16, 2010 #21

    shafferpilot

    shafferpilot

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    twins largely get a bad wrap. They get into trouble because manufacturers convince would be pilots that the plane should fly perfectly fine on one engine... that's simply not the case. However, there are certainly times when some remaining thrust makes the difference between making an airport and landing off-field. The accident rate of twins is slightly higher than that of singles largely because of the temptation to try and fly the pattern back to the pavement when one engine fails on climb-out (a mistake unless you really are a pro). Actually, if single engine pilots really pushed to do the good ol 180 degree turn on engine failure, the accident rates would likely be identical. Luckily, training emphasizes landing off field straight ahead rather than spinning into the ground while trying to turn around... I'd suggest the same concept in your twin, but with one remaining engine, you might be able to make it to an airport out in front of you instead of ending up in a field. Climbing in a twin with one engine out is just about the stupidest thing to even try and do, so in my opinion it's nearly criminal to even publish those numbers. Maintaining altitude and jamming hard on the rudder to keep it straight can work. Keep that speed up, and don't tempt fate.
    Ultimately, choosing a twin because of "safety" concerns already shows a lack of realistic judgement. Stick with the relative simplicity of a single and if the engine fails, concentrate on flying the plane and getting on the ground it one piece. However, if a twin is what you want because it fits other needs like range, performance, price, or aesthetics; than that is the way to go. BUT be very critical of any "it's gotta be twice as safe" thoughts. They will get you into trouble.
    BTW B-17 pilots, while incredibly brave aviators, recieved so little instruction that the REAL stories of returning with severely damaged aircraft are very few and far between. And even those stories are likely embelished beyound anything based in reality. No offence intended, just a reality check ;)
     
  2. Aug 23, 2010 #22

    TAZAR88

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    New twin engine available in kit : DYNAERO FRANCE
    Two Rotax
     
  3. Aug 23, 2010 #23

    autoreply

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    While some specifications sound way too optimistic, here are the details:
    Twin-R
     
  4. Aug 23, 2010 #24

    MadRocketScientist

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    When you look at the proven specs of all the other aircraft they build its not unbelievable IMHO

    Shannon.
     
  5. Aug 23, 2010 #25

    autoreply

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    Well, an actual flying MCR4S is as heavy as their quote for the new twin (over 400kg), though it has one engine and a huge amount of structures/systems less.

    Simply look at the comparison with other designs (notably the DA42 and the Tecnam with identical engines) and wonder how the hell they can make their airplane only half the weight of the competition (the competition being experienced and state of the art participants too).

    I know an owner of a 4S, and while an excellent aircraft, it's specifications are significantly overstated, especially the weight.

    425 kg empty weight can very well be correct. Without instruments, batteries, alternators, starters, wheels, fluids, fuel pumps, seats, windscreen and so on. But a realistic, ready-to-fly weight, with a basic outfit and the claimed structural limits? No, sorry, simply the weight of the wings, systems and engines+prop is enough to make sure that's not realistic.

    The reason I'm so quick to judge is that I'm designing a 2-seat twin aircraft which uses the same engines (but Turbo-ed, thus 50 lbs heavier) I quickly found out that, while your structure doesn't have to be that heavy, all required systems, instruments and all those tiny other things quickly add up to a significant weight.
     
  6. Jan 1, 2011 #26

    Mac790

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  7. Jan 2, 2011 #27

    Titanium Cranium

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    I have read and heard a good deal of opinions on twin engine planes in regards to their safety lately because I'm about to start building a P-38 lightning myself. I chose this aircraft design for many reasons which had a great deal more influence than the safety aspect of having 2 engines. The biggest reason is that my Grandfather was a P-38 fighter pilot and because of that it has the most meaning to me. My Grandfather LOVED having that second engine every time he flew his missions because it would get him home just as it got many of his fellow pilots home after some very nasty dogfights. That makes me believe that with good training a 2nd engine can in fact be safer. Another amazing man I had the priviledge of meeting just yesterday re-affirmed this to me. The man was a WWII pilot who flew mostly B-17 and B-24 bombers but also flew multiple missions, including photo recon, in the P-38. As soon as I mentioned the P-38 he lit up and the first thing he did was praise the plane for having those 2 Allison engines because of how they got his friends back home despite anti-aircraft fire eliminating one of the engines. He also said he would rather take a beating in the B-24 compared to the B-17 because despite being more physically more difficult to handle, the aircraft was more capable of getting home after losing 1 and even 2 engines. I'm not a pilot yet so obviously my opinion means much less than those of you who are, but when I get strong testimonials like those directly from the pilots who experienced it, it just reassures me that with training and good handling of an engine-out situation, having a 2nd one going is always better than having none.
     
  8. Jan 14, 2011 #28

    mkjprice

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    In my experience, as with all aircraft, twins have their pros and cons. Yes you can fly on one engine, should you loose one of them. Does it climb well? In my limited experience No! and only up to a certain altitude. You are much more limited in the manuevarability and controllability of a twin when flying on one engine, but it can be done. I have flown instrument approaches with one engine. There is great value in the redundancy of another engine. For a kit built/home built aircraft, I would lean towards a centerline of thrust Idea, instead of 2 nacelles out on the wings. With the center line of thrust you will not have to worry about Vmc issues (which can kill you quickly) and there is inherently less drag, as the pusher engine is behindthe fueselage. Is a centerline of thrust technically a cheater twin, IMO yes, but if you are only looking for the redundancy of an additional engine, then I think it is the best way to go, and will be the easiest to fly. FLying would likely be similar to a single engine with a few more levers and gauges on the panel.
     
  9. Apr 14, 2011 #29

    stevetosh

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    With 2 engines you are much twice of getting engine failure than single engine, and to my limited experience twin engine are mistake unforgiven most of the time.
     
  10. Apr 14, 2011 #30

    topspeed100

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    Since you wear space suit..how about this wooden design with 2 x P&W610F engines. Supersonic at dive.

    Further planning not available right now. This would use the VLJ Eclipse 500 engines...and this particular specimen could be used to defend your properties very successfully as it is armed with two 20 mm cannons.
     

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  11. Apr 16, 2011 #31

    JMillar

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    Looks like HumanPowered and lr27 are talking about different things. "Twins on one engine" was supposed to refer to an engine-out condition, but it looks like it was read to mean "twin props driven by a common engine."
     
  12. Jun 17, 2011 #32

    Jimwrey

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    That would have been a bit unusual (the back to England part) ... My uncle was 8th Air Force on B-17's. Italy was the MTO they did not have the "legs" to make a combat run back to England. BUT yes, an impressive aircraft. My uncles 17 got cut in half by 88's and they all managed to get out and spent 9 months POW in Germany.
     
  13. Nov 29, 2013 #33

    toucan2plus2

    toucan2plus2

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    Hi,

    I saw your note online, so i joined here.
    You might find ours interesting academically, we are not selling at the moment.
    LIGHT CENTERLINE TWIN

    Cheers,

    drh
     

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