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  #16  
Old 08-19-2006, 02:19 AM
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Kumaros Kumaros is offline
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ChasingMars, thank you very much for your input.
As I said, my figures are just informed guesses and extrapolations. It's your kind of knowledge that is needed here.
I guess the wings don't have to be entirely delta as in the Bateleur, we could have short delta (more like trapezoid) strakes for protection from FOD and easy trailerability and Cozy-like wings and winglets for efficiency's sake.
So what if your regulations limit you to 4 places? You could have a 4 place with huge luggage carrying capacity
I think such a plane with slightly lower Vc but much lower landing speed would be eminently suitable for places like Canada, Australia, Africa with wide open spaces and lots of unprepared places to land.
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  #17  
Old 08-19-2006, 05:50 AM
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karoliina karoliina is offline
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Well, a definition of dream plane for me is the following:

- 4 seats is perfectly fine. I don't actually need them all even.
- However, there could be a mini-kitchen, at least a refrigerator and a little toilet and a configuration that would allow movement inside the cockpit (meaning from pilot seat to toilet and back)
- back seats configurable as bed
- The plane would be pressurized and optimized for high cruise altitudes (like 60000 ft)
- Speed would be gained with altitude
- Basically it would be like a engine powered high speed glider
- extremely long endurance allowing trans-Atlantic flights
- low cabin noise

* very long canard
* even longer main wing

In other words Rutan Proteus with a bit more cockpit space.

Is this doable? Certainly. For one guy on this planet, Burt Rutan. Not for me (unfortunately).

Oh, the grass fields don't really fit with the mission profile of my dream plane.
This one would be too large for grass fields.
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  #18  
Old 08-19-2006, 07:16 AM
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Karoliina, believe it or not your dream plane does in fact exist ... almost.
A French documentary maker, Hubert de Chevigny, had a huge amphibious aircraft made (it would come in handy with all those Finnish lakes, wouldn't it), complete with walk around space, bamboo furniture, a bed, everything.
Google for "Hubert de Chevigny" and "Nicolas Hulot" and Explorer and you'll see what I mean. Of course it takes two IO-540's to fly, but what's a couple of hundred HP's between friends?
Seriously now, the Balled Eagle could easily accommodate your wishes:
1) the table top between the two rear seat rows could drop to seat level and form a bed, quite common practice in campers.
2) one of the seats could contain a chemical toilet.
3) a little Peltier chip refrigerator doesn't take much space.
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Last edited by Kumaros : 08-19-2006 at 07:41 AM.
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  #19  
Old 08-19-2006, 01:54 PM
chasingmars chasingmars is offline
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Quote:
Originally Posted by Kumaros
So what if your regulations limit you to 4 places? You could have a 4 place with huge luggage carrying capacity
Nono... you see, then, when I really want to get Marc Z. spooled up, I wouldn't be able to suggest putting an winged trailer on my Cozy for cargo hauling! :P (just joking, and honestly, I'm one of the ones here who thinks that Marc's a good counterbalance here for some of the wackier ideas - then again, I've also got a background in engineering, including some Aero, so I can usually see his point).

Craig.
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  #20  
Old 08-19-2006, 02:14 PM
chasingmars chasingmars is offline
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Quote:
Originally Posted by Kumaros
Presently the most suitable candidate seems to be the Mercedes Benz 3.0 liter V6 turbo-diesel at 208kg dry weight and 224HP, chipped to ~250 or even ~275HP
I like this engine, I posted about it here wondering about detailed weights (i.e. what's included in the 208kg) because I'd love to find a way to use one in my Cozy, but I fear it's just too heavy...
but...
As much as I'm one of the ones who feels that automotive conversions can be made as safe as aircraft engines (with appropriate, usually extensive, ancil changes and system redundancy), I cringe when someone suggests chipping them for more power.

Fundamentally, automotive engines - including diesels - are light duty cycle engines, and aircraft engines are not, they run at substantially higher power settings. With the stock powerband, I figure you're in a roughly even trade, with a good engine, on wear and life between the increased power settings and the nicer more constant loading. Many of these diesels are quite bulletproof, but I'd recommend against chipping them without substantial data as to what that does to durability, we're building cruising plane engines not race engines and there is a big difference. There is a temptation to uprate because of diesel's reputation for both being heavy and being reliable, I suggest you resist it!

That said, I'm aware that many diesels are somewhat power limited in order to limit smoke production, I drive one of them (a 2001 TDI) - but still, I've pushed that engine while towing too much weight, and while it didn't complain (once, the second time I had power loss, but that was dirty fuel, still, pushing the engine probably made it worse) - after 3 hours at about 75% power (full throttle at 3000 rpm) I got the sense that it would do that all day at it's stock design, but that if it was chipped I wouldn't have been able to use the extra power for too long.

So - if you insist on chipping (I know you have intentions for diesel in your bird), research, test, and do like Rotax and put a big sign on the throttle limiting you to 5 mins take off power at your uprated power.

hmmm... that was longer than the 2 lines I intended to write about this.

(p.s. yes - I know diesels don't have throttles, the pedantic can substitute whatever I'm really supposed to call a throttle on a diesel)
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  #21  
Old 08-19-2006, 02:49 PM
Leon Leon is offline
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well there are examples of the same engine putting out different power ranges. i drive one.

the 1.9 tdi from VW/Audi was first available with 75 HP normally aspirated, then turbocharged to 90 HP, later 110 HP, then 115 HP, then 130 HP (with introduction of the PD technology) and in my case even 150 HP, or rather 175 in my case, all without chipping.

I only know the facts for my engine, but here goes. its the same engine in principle, BUT the crank has been replaced by a stronger one, the pistons are stronger, the turbo is bigger, and so on. All this has been done by the maker VW/Audi, not a tuner. So i trust they know why they did that.

So I think its absolutely feasable to chip the MB diesel, but not safely without extensive work to it, improving bearings, using better conrods, using a better crankshaft and different pistons, maybe even new cylinderhead bolts.
this in turn is a serious cost issue ...

BUT as kumaros says, he only wants to chip the engine to improve short time take off power, its not that he wants to supercruise at mach 1.3

For this case, I'd prefer having a WOT switch that switches to the high power mapping only when the throttle is really at 100 %, and there only. in all other cases it should just run on stock, if you dont want to really go into internal improvements.
i've seen engines spit out a conrod it pushed to far, not funny on a motorcycle where the conrod might just hit your balls ... even wose if it hits the balled eagle's balls

but im all for the diesel thing, as you already know
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  #22  
Old 08-19-2006, 03:18 PM
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ChasingMars, you are right of course, and in all my posts about engines I always add the disclaimer "chipped to *HP for a very short time, just for takeoff and initial climb". Then again you are surely aware of the speed and endurance record three MB cars set with these engines. Search this forum for diesel and Laredo for the related thread. I'm sure they are up to a 20% power boost for let's say 3-5 minutes, just for takeoff and clearing obstacles and climbing to an altitude safe for gliding back to the runway.
As for the weight of the engine, and its being quoted as 208kg, it's supposed to be dry weight according to DIN (Deutsche Industrie Normen = German Industrial Standards). I did my damnedest to find the applicable standard, googling after all kinds of words and combinations thereof, and came up empty-handed. I guess I'll have to use my connections to the Athens MB dealership to find out more, since I'll be doing it anyway for a wiring diagram and a shop manual for a Smart Forfour, the Daimler Chrysler car that uses the same engine as my engine donor car, a Mitsubishi CZ3 DI-D.
Greece, with its multitude of islands and generally poor transport services, would be a virtual playground for the aircraft I'm describing. With a maximum distance from Athens to any border of less than three hundred miles, who cares about max speed; it's the minimum landing speed and ability to handle rough/unpaved airstrips that counts. Just yesterday, I was reading an article in an old German magazine about the troubles of a SpeedCanard pilot who flew from Germany to Oshkosh and back by the northern route and suffered a chipped and cracked prop in Kulusuk/Greenland of all places, and the prop manufacturer, Hoffmann , could only fix it in five weeks The poor chap had to fly home on a commercial flight from Iceland and go back to pick up his aircraft after more than a month. You couldn't pay me enough to fly a Hoffmann prop, let alone pay ~US$10k for the privilege.
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Last edited by Kumaros : 08-19-2006 at 04:05 PM.
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  #23  
Old 08-19-2006, 04:37 PM
SteveWrightNZ SteveWrightNZ is offline
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Quote:
Originally Posted by chasingmars
That said, I'm aware that many diesels are somewhat power limited in order to limit smoke production, I drive one of them (a 2001 TDI) - but still, I've pushed that engine while towing too much weight, and while it didn't complain (once, the second time I had power loss, but that was dirty fuel, still, pushing the engine probably made it worse) - after 3 hours at about 75% power (full throttle at 3000 rpm) I got the sense that it would do that all day at it's stock design, but that if it was chipped I wouldn't have been able to use the extra power for too long.
No, diesels are quite different to petrol engines.

With Diesels, you need only one thing to make power, and that is BOOST !!

Diesel compression-ignition engines EGT goes DOWN with increased MAP. The OPPOSITE to petrol spark-ignition engines. More MAP = LOWER EGT.

For aviation use, simply rebuild the turbo system to run twin-compounding turbos, and double or triple the factory boost, then start playing with fuel and watch what happens.

The compression ratio should be lowered for very heavily turbocharged engines. Modern turbo diesels are very low compression ratio. I think.

I built a lowered-compression diesel to take twin compound turbo, but I havn't got to adding the turbos yet. Its a little hard to start too


S
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  #24  
Old 08-19-2006, 05:01 PM
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As mentionerd in a previous thread, and as Steve says, diesels thrive on boost. This same engine in SLK triturbo form produces 286HP, and cars are driven for endless hours on German autobahns at WOT, or the diesel equivalent thereof, so I would have absolutely no compunction in driving this engine to ~275HP for a couple of minutes and ~200HP all day long for a month.
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  #25  
Old 08-19-2006, 06:44 PM
chasingmars chasingmars is offline
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The SLK uses an uprated OM642?? Interesting, didn't know that ... going to have to look into that - could be interesting... <trundles off to research...>

p.s. I know diesels like boost, and are built to take it, I'm just saying, there's mechanical strength issues in the engine components (i.e, as the previous posted mentioned, stronger crank for hight output) and you bite into that reserve when you uprate... it's not just about EGT and cooling capacity (interesting tidbit, that MB engine has a 15kw heat exchanger to dump oil heat to the coolant... keep the temps even)
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  #26  
Old 08-19-2006, 11:16 PM
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ChasingMars, just google for SLK and triturbo and 286, and you shall find.
An interesting find from your neck of the woods, or maybe not, I'm not so clear about the geography of Canada:
http://www.montrealracing.com/forums...d.php?t=209404
AFAIK, the higher horsepower is the result of better plumbing, as in three turbos, two small and one big one, and better breathing, as in larger air-charge and exhaust piping. Nothing a dedicated amateur couldn't do by him/herself.
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  #27  
Old 08-20-2006, 12:25 AM
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Quote:
Originally Posted by Kumaros
With a maximum distance from Athens to any border of less than three hundred miles, who cares about max speed; it's the minimum landing speed and ability to handle rough/unpaved airstrips that counts.
Why try to adapt a canard for this purpose? There are a muiltitude of other planes that will suit these purposes, to include easier use of alternative engines. The *only* benefit I can see of the canard planform are great long-range travellers with generally optimal mpg.

The ease of the moldless construction technique could be easily adapted to creating a Cessna/Aerocomp clone to use as a base for alternative engines, camping inside, etc. The design process would be much more straight forward.

The canard/stall-resistant thing I think is way over-rated...other than this point, why stuck on the canard planform?
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  #28  
Old 08-20-2006, 12:49 AM
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Choice of aircraft being a highly subjective process, I can only state my criteria, not necessarily in this order:
1) Looks, have been in love with Rutan canard designs and derivatives thereof ever since that Popular Science or was it Popular Mechanics cover story in the seventies.
2) Cross country performance. Please note, I don't want to clip the Cozy's wings in this respect, just trade let's say 20% of its max speed for 30% of lower landing speed, making it more suitable for beginner pilots, or short/rough airstrips. Based in Athens/Greece I'd like to have a dual mission plane, cross country for those occasional trans-european trips, reasonably STOL capable for those island airstrips. I'm sure lots of people here would agree with me that they'd gladly sacrifice 20% of top end performance for 30% bush ability.
3) Plans built, an excellent way to exchange sweat for dollars and spread the cost over a longer time period.
4) Blending the Bateleur and Cozy characteristics would create the perfect aircraft as far as I am concerned. I really like the propeller being protected from FOD, everything else is just icing on the cake.
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  #29  
Old 08-20-2006, 01:26 AM
SteveWrightNZ SteveWrightNZ is offline
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Quote:
Originally Posted by chasingmars
there's mechanical strength issues in the engine components (i.e, as the previous posted mentioned, stronger crank for hight output) and you bite into that reserve when you uprate... it's not just about EGT and cooling capacity
Agreed. At that point compression ratios should be lowered to avoid cracking pistons etc, similar to spark-ignition engines, viz the Avensis is 15.8:1. Likely you can push a lot of boost up that without upsetting it.
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  #30  
Old 08-20-2006, 03:06 AM
chasingmars chasingmars is offline
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I've heard the trend to lower compression auto diesels is to reduce NOx, are there other rational as well?
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