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  #31  
Old 06-01-2005, 11:25 AM
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JonC JonC is offline
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Actually the comment about the engine only taking you to the crash site is about right. Multi-engine piston planes rarely have the power to climb at a decent rate on a single engine, let alone hold an altitude that would clear a low mountain. The obvious exception is some turboprops and most turbojet/fan multis. The Falcon 10 manual I read once refers to an engine out as an "abnormal" procedure... no meantion of emergency like there is in a piston.

Twins are designed to fly on both engines, and have just enough power on one to get you out of harms way or to a more suitable place to crash. If you were to put two engines on the plane that were capable of flying the plane alone then you would have just wasted a great deal of useful load for an event that might happen once or twice the whole time you own the plane.

All this is meant to be constructive.... we are just pointing out how it is with mutlis.
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  #32  
Old 06-01-2005, 12:58 PM
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Quote:
Originally Posted by JonC
Actually the comment about the engine only taking you to the crash site is about right.
While In general I won't argue that, I would point out that the Venezuelan twin coaxial is capable of maintaining 8000 ft (density altitude) and 110 kts at gross on one 100 hp engine.

Quote:
Originally Posted by Kumaros
changes to the Cozy may have to be somewhat significant, certainly a larger canard, a fixed front gear to free the larger and/or longer nose for the second engine, etc., but always peripheral, not to the main fuselage itself.
not sure on that last part. That firewall up front has to carry a large load, think about the increased loads on the front gear on a hard landing. Those loads have to connect back to the spar, don't they?

Quote:
Originally Posted by Kumaros
hanging two huge displacement aviation engines at both elongated ends of the Defiant, with their commensurate thirst for fuel, dictates strong, vibration resistant structures, huge fuel tanks etc., and lift to match, it's a vicious circle.
Maybe an aero engineer can give a more authoritative answer here, but I don't think Burt didn't made that canard 24 feet long because of vibration issues, nor because of the extra fuel. the canard is that long and wide because of the engine weight. The structure is beefy because of all the loads up there: Landing, Canard lift, engine thrust, torque, and weight. Your plane will have all these loads as well.

Defiant weights in at 1380 lbs empty, 3000 gross (I think) what are DefCon III's target numbers?

All this dual engine talk has stirred up the fumes in my head...I wonder if the Cozy IV rear is big enough to share 2 13B's, Leon-style.
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  #33  
Old 06-01-2005, 02:25 PM
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Kumaros Kumaros is offline
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Quote:
Originally Posted by JonC
Actually the comment about the engine only taking you to the crash site is about right. Multi-engine piston planes rarely have the power to climb at a decent rate on a single engine, let alone hold an altitude that would clear a low mountain. The obvious exception is some turboprops and most turbojet/fan multis. The Falcon 10 manual I read once refers to an engine out as an "abnormal" procedure... no meantion of emergency like there is in a piston.

Twins are designed to fly on both engines, and have just enough power on one to get you out of harms way or to a more suitable place to crash. If you were to put two engines on the plane that were capable of flying the plane alone then you would have just wasted a great deal of useful load for an event that might happen once or twice the whole time you own the plane.

All this is meant to be constructive.... we are just pointing out how it is with mutlis.
Jon, I know you are all trying to dissuade me from chasing chimeras, metaphorically and literally. Having, however, clearly stated time and again that the second engine is there for added safety over long legs over water, the Mediterranean, the Black Sea, eventually the Atlantic, I don't need reminders on how twin spam cans operate. With my aviation engines of choice, Mitsubishi or FIAT (actually both these companies have an aviation history Lycoming would die for) and their ample torque from low RPM's, I am confident that one of them would be able to sustain flight. Look at Thielert Centurion's ability (a 1.7 turbodiesel at heart) to replace a Lycoming IO-360 in traditional spam cans.
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  #34  
Old 06-01-2005, 02:44 PM
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Quote:
Originally Posted by Aaron
snipped ...
the canard is that long and wide because of the engine weight. The structure is beefy because of all the loads up there: Landing, Canard lift, engine thrust, torque, and weight. Your plane will have all these loads as well.

Defiant weights in at 1380 lbs empty, 3000 gross (I think) what are DefCon III's target numbers?

All this dual engine talk has stirred up the fumes in my head...I wonder if the Cozy IV rear is big enough to share 2 13B's, Leon-style.
Now these are comments I really like, even if they blast my proposition right out of the water I would be willing to brave a larger canard and a little strengthening of the nose structure here and there, I certainly am not going to mess with the main fuselage structure. So we are back to the aft engine(s) configuration, with the added advantage that two engines coupled by a common cog-belt to a common prop shaft may be construed as one engine, thus obviating the need for multi-engine training and ratings. As for the Cozy IV rear being able to accommodate two rotaries, I'm sure it can, you may have to move the ancillaries up front though, for space and for weight and balance purposes.
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  #35  
Old 06-01-2005, 04:07 PM
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I just received an email from Ruben Leon. He now lives in Miami. The dual engine now has 600 hours on it. He said that if there was enough interest he might be able to put together a similar system, but that he's made so many modifications to his system he doesn't have a whole lot of drawing of the current setup.

So, when you go to Florida for flight school, jot on down and talk with him. he seems like an affable fellow. I've asked him to join us here if he has a chance.
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  #36  
Old 06-01-2005, 06:33 PM
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Just for the record... I wasn't suggesting the Jabaru engines, I was just displaying the photo as an example of mounting twin engines on the spar.

I thinks something is being lost in translation here...
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  #37  
Old 06-01-2005, 07:23 PM
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Quote:
Originally Posted by Kumaros
No Mike, I don't misunderstand the FAA directive, that was exactly the gist of my question, hence the remark "SOLO and otherwise". Maybe I didn't formulate my question clearly enough. OK, according to your answer, I can fly an experimental whatever SOLO, but need the appropriate rating to carry passengers. So, I ask again: is there a special (simplified?) multi-engine in-line thrust rating?
Kumaros
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To get an FAA Multiengine Rating you have to take the flight test as specified in the Practical Test Standards. If you TAKE the flight test in an aircraft that has only center-line thrust, then you are RESTRICTED to an aircraft with centerline thrust. The test itself is not that different: You still have to handle single engine tasks, but in a C-L-T plane these are not complicated by assymetric thrust.

Make sense? The FAA CLT "rating" is actually a "restriction" on a Multi-engine pilot cert.

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  #38  
Old 06-01-2005, 08:05 PM
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To start with, I know nothing of x-plane, tho I wonder about it's capabilities, some folks at Homebuilt forum use it to "prove" the most unreasonable looking things will fly. Might be worth posing the original question there.

If you've been perusing the old CP you may have found the one where Dick Rutan had an engine failure in the Defiant. With both engines pulling/pushing the same rpm and no real hint on the panel until the temps started to fall he had to ask the chase plane for hints on which engine had failed!

I know you don't want to hear this, but your stated aims of cheap to build and not being an engineer scream "Bolt on an O-320" to me. It'll fly nice, like hundreds of 'z' before it, cost about the same and be worth more.

Burt seemed to yearn to redefine how to control aircraft. The Vari originally had no ailerons but it didn't work very well. I've read he regretted the rhino rudder in the Defiant, and have also real there is at least one Defiant with Long-style rudders. Not sure which I'd go for.

Could I propose a bit of etiquette? When replying to a specific post in a forum such as this, could we restrict ourselves to just 'quoting' the bit we are specifically answering, and only do that if you are seeking to really emphasise something? If I want to read the whole thing I just have to push the 'up' button??? While the Twin-suzuki cozy is nice, I didn't need to download the picture on my cr@ppy dial-up more times in quotes!
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  #39  
Old 06-02-2005, 08:45 AM
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karoliina karoliina is offline
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About dual engines in the defiant style, have anybody though yet
another option that wasn't discussed below. Of course the front
engine will eat up the front seat space. But what if one builds
the plane differently by moving the front seat backwards and perhaps
compromising the back seat (e.g. for a storage space without seats).
Now the Cozy has the front seat in front of the CG. How about putting
the crew nearly at CG and placing a engine to the front.

About what Kumaros said about getting PPL in less than a month,
to me it sounds quite unrealistic plan unless the Cessnas are
very easy to fly (haven't tried so far). I have now about 70 hours
of experience in my light plane and between 300 and 400 landings
and it doesn't feel like I would master it so very well so far.
Most people need a year to get yet alone UPL here (minimum of 20 hours
of flying and 60 hours of theory) and JAR-PPL takes
even more time. 100 hours of theory, at minimum of 45 hours of flying.
After that you have VFR and single engine rating only. For multiengine
one would propably need here ATPL with multiengine and IFR, which
can cost between 50000 and 100000 EUR if I am not totally mistaken. However, there is one way to get around this by owning a IFR-certified
aircraft - no rental feels in training. One person I know bought a IFR-Piper
and got his IFR certificate with that. He also got ATPL and propably
multiengine somehow that I don't exactly know but it still wasn't very cheap. In this country you could not fly IFR with experimental anyway and not even night-VFR if you don't have a certified aircraft engine and certified instruments - in other words Diesel Cozy in some other form than
equipped with certified Deltahawk or Thielert Centurion engine, you would
be limited to day-VFR only (flight only during days and good weather).
I don't know how would be the case with a twin experimental, is it possible
or not, if I am suspecting right, there is some obstacle that makes doing
a such thing impossible with the regulations here.

Do you want to know more about Finnish weird things:
- I have an experimental aircraft which is not certified aircraft, but it is
manufactured in a factory and has type certificate. The type certificate
is written in too much detail. Therefore even changing the bad no-name
headsets to some high quality headsets is forbidden (it would be
considered to be a big change which would propably require test
flights again). This is a really mad country with bureaucracy sometimes.
At least now I know a single very good reason to not own a factory built experimental which has a type certificate. The hairsplitters are really
experts in what they do and they misleadingly call it as "safety".
Sorry for my rant, but I am a bit on a bad mood because I walked
to a brick wall with my plane repair attempt (a bad non-functioning
instrument is ok, a good well-functioning
replacement for that is not, and it is all about safety i.e. kinda "spam can safety" - yeah this is safe because this certificate says so and it can NEVER fail even if has already failed (Suggestion from CAA: you should have read the manual), yeah right, quite the same as our PC support when I once told that my hard drive has failed (explained bad block stuff etc. and it no longer works even if I try to repartition and reformat it) and I need a new one - the first question was "have you tried to reboot your computer"...).

Anyway, if I will build a canard aircraft, I will be propably spared from a great deal of bureaucracy and especially backstabbin from CAA and Finnish EAA side in that matter if I build one with just single engine and keep the amount of modifications low and reasonable.
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  #40  
Old 06-02-2005, 10:42 AM
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Kumaros Kumaros is offline
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Quote:
Originally Posted by Aaron
I just received an email from Ruben Leon. He now lives in Miami. The dual engine now has 600 hours on it. He said that if there was enough interest he might be able to put together a similar system, but that he's made so many modifications to his system he doesn't have a whole lot of drawing of the current setup.
Thank you Aaron, this is good to know. I may put together a similar system, only not coaxial shaft / counter-rotating props, too complicated for me. I'll probably use two engines driving a single prop through a common cog-belt.

Quote:
Originally Posted by Aaron
So, when you go to Florida for flight school, jot on down and talk with him. he seems like an affable fellow. I've asked him to join us here if he has a chance.
Again thank you, even though it will be at least a year until I finish the plane and be ready for flight lessons. As a side note to Karoliina's post, she should pick up any European amateur aviation magazine and look through the last pages, ad after ad by Florida and California flight schools offering to train anyone, especially Europeans, for a PPL within 20 to 25 days for about US$ 5000. Taking advantage of the almost guaranteed good flying weather, they program 2 or 3 hours of flying per day, completing the 40 to 50 hours necessary for a PPL in less than one month. The rest of the day is dedicated to intensive ground school lessons, simulator training etc. Before going there I'm going to attend our local Aero-Club ground school too. In my opinion, money well spent.
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  #41  
Old 06-02-2005, 10:56 AM
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Quote:
Originally Posted by Spodman
:
snipped ...
I know you don't want to hear this, but your stated aims of cheap to build and not being an engineer scream "Bolt on an O-320" to me. It'll fly nice, like hundreds of 'z' before it, cost about the same and be worth more.
snipped ...
Thanks for the suggestion mate, but no thanks. "Aviation" engines were actually free for the taking about ten years ago, when many US bases in Greece were closed down and abandoned, complete with emergency power generators with guess what? ground versions of your beloved aviation engines. I wouldn't touch them with a ten foot pole. Have you ever read any of my posts? Are you aware of the price difference between avgas and Jet-A or diesel in Europe? Are you aware of the fuel efficiency difference between "aviation" engines and turbodiesels. Are you aware of the reliability advantages of diesel engines? As for me not being an engineer, that did never stop me from maintaining and repairing every single vehicle I've ever owned from my first Fiat 600 to the latest Renault Twingo, even to the point of changing the engine of a Suzuki microbus I bought with a totally crapped out two-stroke engine, which I replaced with a four-stroke one, designing and fabricating a new gear-change mechanism, because they were different...
If I were ever to visit you in Daraweit Quim, though God knows why I would ever want to, it would cost me a year's income in avgas, but a month's in diesel.
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  #42  
Old 06-02-2005, 11:04 AM
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Quote:
Originally Posted by karoliina
snipped ...
About what Kumaros said about getting PPL in less than a month,
to me it sounds quite unrealistic plan unless the Cessnas are
very easy to fly (haven't tried so far).
snipped ...
Karoliina, please see my post to Aaron. As stated there, all major European aviation magazines are full of ads by Florida and California flight schools offering 40-50 hours in 20 to 25 days training programs for a PPL. I can scan and e-mail you a couple of pages of the "Flieger" magazine, I subscribe to.
As for your Finnish bureaucracy woes, I can only commiserate, as we have almost the same problems here. Word to the wise to our US friends here, hold on to your rights.
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  #43  
Old 06-02-2005, 11:11 AM
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Quote:
Originally Posted by MarbleTurtle
Just for the record... I wasn't suggesting the Jabaru engines, I was just displaying the photo as an example of mounting twin engines on the spar.

I thinks something is being lost in translation here...
MT I believe you, no need to bang your head so much
Don't remind me of translations, Thursday nights are always the hardest, sometimes working all through the night in order to finish everything before the weekend.
I know you used the Jabirus only as an example, I was aware of that plane, having seen it in the photos from Rough River or something on the EZ Squadron site. Thanks, but in light of the recent FAA directives and the need for a multi-engine rating to fly a Defiant hybrid, I think I'll go the single engine, or two engines closely coupled together route.
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  #44  
Old 06-02-2005, 11:15 AM
swinn swinn is offline
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Kumaros,

Have you thought about alternative engine backups VS. two engines? Would 300 lbs of thrust be enough to maintain level flight in a cozy?

This site:

http://www.aardvark.co.nz/pjet/

Indicates a pulse jet engine that delivers 150 lbs thrust each. They do get a bit warm , and I'm sure the fuel consumption numbers aren't ideal. You can buy the engines pre-made at:

http://www.simplejets.com/

I'm not trying to be funny, I really think this one or two of these engines might provide enough oomph to keep a cozy airborn and they look like they are fairly light weight, compared to a piston engine certainly. Perhaps it could be built into a pod under the wing similar to the baggage pods that you can build. Currently they run on propane, but I would think that they could run on pressurized diesel as well.
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  #45  
Old 06-02-2005, 11:50 AM
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Kumaros Kumaros is offline
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Quote:
Originally Posted by swinn
Kumaros,

Have you thought about alternative engine backups VS. two engines? Would 300 lbs of thrust be enough to maintain level flight in a cozy?
snipped ...
Have I? from JATO bottles to those little AMT jet engines, Cri-Cri flies with. These would be cool to have as a backup or just to show off at air-shows, if they could burn kerosene (Jet-A). At altitude they would be even more fuel efficient. I don't know if the thrust is enough to maintain flight in a Cozy though.
Truth be told, I had never thought of a pulse jet. Actually, given the sound pressure levels they generate, the middle of the Atlantic would be the ideal place to test them
Come to think of it, a JATO bottle strapped to the fuselage Wile E. Coyote fashion, would be good insurance against an engine out during take off, at least during the first 40 hours. John Slade are you listening?
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