experiamental fighter jet style aircraft

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by T-51ls1, Dec 7, 2012.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Dec 16, 2012 #141

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America

    I once knew a man who kept telling me, "my wife makes me hit her".
    Lets be careful with blaming others for your actions. If you need to
    "vent" do it off-line or send me an email; the last thing newbies need
    to hear about is your troll problem.

    I also hope your Trolling problem goes away; I'm looking forward to
    another 2,000 posts from you! :smile:



    As to the OP's original request. I'd suggest building or buying an Ultralight
    until you decide on your next project. Time and experience may change your
    wish list.

    Best regards,

    Detego
     
  2. Dec 16, 2012 #142

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    I have proposed electric psru in my blog a long time ago already:
    pros:
    - with series hybrid propulsion, the car engine (or motorcycle engine, been looking Hayabusa engine with some interest) can be always ran exactly at its optimum and it is mechanically simple and not hard load for the engine, it only turns an electric motor to produce electricity.
    - placing electric drive motors to aerodynamic optimum is not a problem and no drive shafts will be needed, e.g. in pusher configration due to the smaller footprint of the brushless DC motor.
    - the generators never need to be run with excessive power if the power is buffered with small batteries or super capacitors - for rapid takeoff acceleration and initial climb out
    cons:
    - suitable motors for generator and propeller drive function are hardly available and same goes with the ESCs, these would need to be designed for the task.
    - weight penalty for having two high power brushless DC motors in addition to the engine, could be most effective if mated with very lightweight engine to compensate
    - if batteries are added to equation, having enough high discharge rate causes some weight penalty

    I am planning to do some related development & testing in RC-scale. Do not expect any results anytime soon.

    Hayabusa engine has the following footprint
    - almost ~180 bph in motorcycle
    - 80 kg (similar to Rotax 912)
    - lots of power headroom to 'derate' from in generator use

    It could be possible to make a generator package with two Hayabusa engines and two motors. There could be 1 or more drive-motors turning the props. In cruise the other engine could be turned off and it would function as spare. Unlike in traditional twins.
     
    Last edited: Dec 16, 2012
    Detego likes this.
  3. Dec 16, 2012 #143

    Kristoffon

    Kristoffon

    Kristoffon

    Well-Known Member

    Joined:
    Sep 4, 2009
    Messages:
    348
    Likes Received:
    20
    Location:
    Brazil
    Or you could have four hayabusa engines without any generator and battery nonsense for the same weight.

    Who needs a 10% gain in aerodynamic efficiency when you can have a 100% gain in power/weight?
     
  4. Dec 16, 2012 #144

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    To add one more thing: the jet engine requires enormous amount of fuel on board, just checked Viperjet case. With series hybrid propulsion with their original concept would have worked, and it would have been lighter (with less fuel required) than all that jet fuel that is burned with poor efficiency in the turbojet engine. Of course it may not appeal for some people so much with a prop than with a real jet.
     
  5. Dec 16, 2012 #145

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    373
    Location:
    Zagreb HR
    If you go back to my words you'll notice that I said the BD was a brilliant idea in the late '80s, not that the plane itself was brilliant because it suffered major problems, as noted. The idea of a private Jet lighter than 1 ton is still unmatched even today, and is a brilliant one if those problems of BD-10 like jets could be overcome. The ViperJet is a good example that it can be done better yet it's empty weight is way more than a ton.

    The BD-10 was an airplane designed around an overpowered engine. There is a question whether this method was responsible for the result of heavy fixes - some 300kg of excessive weight and the airplane still suffered structural problems. A test pilot even reported that the airplane was disintegrating in flight, at speeds less than the planned 1.4 Mach. Never the less, the power to weight ratio was still remarkable at the time (more than 20 years ago) and matches those of modern jets.

    Now, feel free to point out to those experimental homebuilt fighter jet style aircraft that have a power to weight ration of more than 1:1 and less than 1 ton of empty weight. Which I firmly believe would be an outstanding achievement. It would really be interesting to see those concepts.
     
  6. Dec 16, 2012 #146

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    You can drive the engines at optimum SFC all day long this way. And you can design a twin which is flown with one engine for low fuel consumption in cruise and no asymmetric thrust problems, and it is no problem to design the plane to cruise exactly at L/D speed. And you still have another spare engine in case primary would decide to fail on top of big ocean.

    But in this particular case the install geometry for 'jet fighter' looks would be driving factor rather than my primary interests. You can not mount 4 engines to 4 props and at the same time have it look like Viperjet. Especially without failing drive shafts and failing PSRUs. PSRUs are used widely without problems, but somehow airplane people tend to fail with those extremely often, only Rotax can design them it looks like. The electrical propulsion will opt out from these mechanics that have poor track record. And two of these could be enough to turn an EDF for more authenticity at the expense of potential efficiency loss, for the jet looks & feel, making it a 'cold jet'.
     
    Last edited: Dec 16, 2012
  7. Dec 16, 2012 #147

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America

    I've been leaning towards the Diesel Motor/Generator, combined with Electric Motors. If were talking
    25 - 50 hours yearly usage; the Diesel Motor/Generator could be much 'less robust', than say for 24x7
    Operation; knowing that you need to Rebuild the Engine within 500 hours, could be considered an
    acceptable expense, with a simple Motor and parts availability.


    As for the "proposed electric PSRU", I'd be concerned with running a single Electric Motor application.
    You could run the PSRU as a single mounted setup but utilizing dual electric motors on a single shaft;
    This would split the load across two Electric Motors, also saving on wear & tear, etc.
     
  8. Dec 16, 2012 #148

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    Detego: tue, but electric motors can be designed for any power needed, dual motors do not add significant safety, because brushless DC has one part ype that may fail: bearings. Bearings can be chosen for very long service life. But two props would add safety because prop failures unfortunately does happen. Dual motors will be spinning their KV-speed when the prop departs and the plane will ditch.

    Of course if you can not design and fabricate custom motors and controllers yourself, this would become very tricky especially in regard of ESCs. Highly efficient drive system is unnecessary for a plane that only flies 25 hours per year. I am considering one flight to last 25 hours.
     
    Last edited: Dec 16, 2012
  9. Dec 16, 2012 #149

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America


    I'm thinking about the continuous load on the e-motor, and my experience with failures of one e-motor to
    sustain the loads as two.

    As to your above points - your right - redundancy is preferred; I'm hesitant about plumbing and using two
    gas motors, etc.

    Dual 11's 003.jpg
     
  10. Dec 16, 2012 #150

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    373
    Location:
    Zagreb HR
    Excellent point, maybe the usage of a propfans as some modern airplanes do to reduce the fuel economy and boost efficiency could be a consideration for your application too..?

    The stock Hayabusa 1999-2007 engine has top rated power of around 180HP indeed at the shaft after gearbox. Yet reving it up to those rpm would not be good for a long term usage. So the solution would be to have a turbocharger and a few modifications which could allow this engine to produce around 160HP at 6000rpm or less than 70% full throttle. That would make it long lasting and the fuel economy of some 7 to 8 liters an hour would be good for an aircraft application. Yet the modifications would be quite significant, the only thing left stock in the end would be some parts of the crankcase.

    A better, lighter and more efficient solution would be to find an old 1100 Gixxer crankcase, from one built between 1990 to 1991. Remove the gearbox, oil sump, some other parts of the case and machine a new dry sump, get new sleeves, pistons, piston rods, add double oil pumps used in aviation and a turbocharger, a powercommander for mapping the firing timings and triple spark plugs. Almost everything would be new in your engine and machining most of the parts in the engine would cost quite a few Euros. The machine could outperform and outlast many other engines if it is limited to some 6000ish rpm. The question is, would it be worth the money if you can buy a new aircraft engine that produces constant 160 to 180 HP for a little bit more money and weights around 50kg more? My point is, your idea is feasible yet will the cost justify the usage and need of such a high tech engine... The Hayabusa engine can be run at 6000 - 7000rpm for 24 hours with minimal fuel and oil consumption compared to many other engines in the same class but it will not produce constant 180HP that you might seem to be needing. If you want that much of power there are way to achieve that, but at a higher cost than a completely new stock bike.

    Are there any more details about your project, what kind of experimental are you building, is it a jet fighter style aircraft? If we are talking about the power output of around 180HP keep in mind that BLDC motors need controllers that are quite heavy, with such power need you might controllers that would be heavier than the motors themselves. A more practical solution could be the usage of AC or DC electric motors, depending on your purpose and RPM. But in tha HP range there are few motors that you could buy and consider, you would most probably need to have them custom made, which augments the weight of your airplane. Another idea is to use stacked electric motors, for example 6 30HP motors on triple axis, use all of them during takeoff and landing yet use only as much as necessary for cruise, if your design and structure permits such a solution.
     
  11. Dec 16, 2012 #151

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America

    DZ, whats your experience with the boxer designed "Honda Goldwing GL1800 engine"?

    imgGl18003.jpg
     
  12. Dec 16, 2012 #152

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    Does someone have some study data about propfan? Would be cooler on cold jet than a prop. I have been reading just some non-technical mambo-jambo about the topic which has concentrated mostly on noise and about the turbine engine that turns the propfan rather than actual interesting topics. I am not interested in the turbine nor noise, but would like to see some factual numbers if compared to traditional prop on low to medium subsonic speeds (not reaching even nearly transsonic). I have been doubting that propfan would be (much) less efficient at low speed (from 80 to 300 mph) than larger traditional propeller, but very much would like to be proven wrong on that. If the speed this propfan is not a problem, just a design requirement for the electric motor number of poles and wire length. But that could be a separate topic.
     
  13. Dec 16, 2012 #153

    karoliina.t.salminen

    karoliina.t.salminen

    karoliina.t.salminen

    Well-Known Member

    Joined:
    Oct 7, 2008
    Messages:
    407
    Likes Received:
    80
    Location:
    Finland
    I have been thinking Hayabusa engine for following reasons:
    - water cooled (boxer is a really bad idea despite Lycomings and Continentals are air cooled). Water cooling is much better for engine that is not in the airplane nose.
    - modern DOHC
    - lightweight
    - reported to be reliable
    - Lots of power at 6000 rpm already, compares to Rotax favorably

    I don't understand why anyone would want to put Goldwing or HD engine to airplane. Instead they should look at similar but proven engines from Lycoming and Conti as these Goldwing and HD engines already lack the advantages of these smaller engines.

    Even better than Busa for P/W; ZX6R engine might have still better power to weight ratio, but it may not be the best option for reliability due to higher piston speed. Cost of used Hayabusa engine from crashed motorcycle seems to be around 2000. Eg Gixxer or Zx6R or ZX10R engine do not have price advantage, they cost about the same. I do not know the price of brand new engine for these bikes. But generally the price is very low on aircraft scale due to mass production volumes, one can not even buy 2000 hours end of life Rotax that cheep and one can buy new motorcycle at the price of new Rotax and two new motorcycles at the price of IO-360 and 50 (!) used Hayabusa engines at the price of one TEO-540.
     
    Last edited: Dec 16, 2012
  14. Dec 16, 2012 #154

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,492
    Likes Received:
    2,525
    Location:
    Port Townsend WA
    I have a 1973 SAE paper (730323) title: Shrouded fan propulsors for light aircraft

    It is about using piston and rotary engines to drive fans and the Hamilton Standard Q- Fan study.

    edit:
    this NASA study covers some thoughts of Q-Fan and Auto engine conversions in general.
    warning, very long and hard to read. I think it is a talk transcript. I make the print larger and scroll the bottom to read better.
    http://cmapspublic3.ihmc.us/rid=1040062996171_1314089320_1169/PAVE CTOL Concept Article.doc.htm
     
    Last edited: Dec 16, 2012
    karoliina.t.salminen likes this.
  15. Dec 16, 2012 #155

    Kristoffon

    Kristoffon

    Kristoffon

    Well-Known Member

    Joined:
    Sep 4, 2009
    Messages:
    348
    Likes Received:
    20
    Location:
    Brazil
    This guy built a ducted fan cozy but it must have been not so good because he rebuilt it with a prop and psru.

    If you dig through google there have been a number of attempts at ducted fan canards but since apparently they all remain obscure it seems it doesn't work so well.
     
  16. Dec 16, 2012 #156

    DangerZone

    DangerZone

    DangerZone

    Well-Known Member HBA Supporter

    Joined:
    Sep 5, 2011
    Messages:
    2,107
    Likes Received:
    373
    Location:
    Zagreb HR

    That GL1800 engine is the successor of the GL1500 that was a sixer and weighted more than 110 kg dry, meaning the 1800 engine could weight even more. Honda installed a reverse gear just to allow people to move it around, it was really heavy. I know the 1800 model has an aluminum frame just to try to compensate the weight. It was a comfortable bike for showing off and touring, long straight voyages, the seat was really made well. Most boxer motors come from the era when the engines would stop or start having problems so it was easier for mechanics to turn the screw from the sides and repair the engine on the bike/vehicle. As technology progressed the boxer motor had too much weight, vibrations and disadvantages compared to in line engines. Converting such a GL1800 engine for aircraft use would be kind of a step back if you want some progress and improve performance. If you are fine with the concept then it would be wiser to choose among many Rotaxes, Lycomings and Continentals that share the same principle of boxer motors. They are old and reliable, weight a lot, consume even more and will do so as long as they hold a significant market share and have much influence. To the average homebuilder, they are well proven engines and all of their problems are known to most mechanics. So to sum it all up, trying to convert a GL1800 for aircraft use could be more costly than getting a 120HP aircraft engine without any benefit after all.

    Some 8 years ago I bought a book called Ducted Fan Design, it had some good points about mistakes that many designers make when designing ducts, fan blades, nozzles and quite a few experiences of those who had wrong calculations. It was a pile of photocopies which had some good information about the projects like Smitty Hairplane and Saunders JetHawk, I remember those two. Try googling Mass Flow or ducted Fan Design and see if something turns out, maybe you could find something interesting.

    Later on I met a guy whose hovercraft blades were designed by a Russian aerotech engineer and it was amazing how different those were designed from the western approach, more blades, straight lines, high noise, etc. Those were design specific, if you want to accelerate from 0 to 100km/h in one second or less then such an approach will make maximum efficiency for such goal. On the other hand if you take a look at GE's UDF you can notice scimitar shaped blades, different configuration of pitch control, everything changes. This means that for an application for some low speed from 40 to 300mph the shape of the blades would have to be different and so would the variable pitch system. Compare the GE's UDF to the Antonov blades and they seem similar at first glance yet also different in many aspects. I've seen propeller blades in the shape of propfan scimitar blades because some claim these are more efficient if you don't mind the noise as a problem. In the end, it is always design specific and depends on what you want your plane to do and how you want it to perform.

    I mentioned the GSXR1100 '90-'91 engines because they are oil cooled. The Busa is water and oil cooled as is the ZX10R. Mixing water and oil is not the best idea if the engine goes through high temperature oscillations (from +30 centigrade to -50 and then back) so if you could choose it could be wiser to opt for an engine that is oil cooled. When Etsuo Yokouchi and his team designed the GSXR1100 they had aircraft engines in mind, they made the engine as light as possible, the double oil cooling system (SACS) was calculated to be 5 times more efficient than needed and all of the parts had to be as light as possible. The pistons and cylinders are also oil cooled which contributes to the fact that some of these engines are turboed and overpowered up to 300HP without damage or overheating. No wonder a French company called VIJA is producing these engines for aircraft use, since they do not need many changes and it is a reliable powerplant.

    But buying an used engine, be it the Busa or the Gixxer (Hayabusa or GSXR1100) is just a strat, you need a lot of changes before you put it in your plane. The problem is that you can't buy these engines new, the Busa is sold with the bike frame and all the rest and the Gixxers are becoming rare due to the fact that many people buy them to overpower them. A 150HP GSXR1100 is brutal in force compared to some other 150HP bikes, it is amazing what a good piece of engineering these Japanese have made. An appropriate turbo, quality pistons, piston rods, good sleeves, a power commander with a good fuel injection, a dry sump and machining, and a few other parts needed for a conversion would come up to 15k Euros. But it would be a new 80kg engine capable of 160Hp for a sustained flight for 24 hours. Need to get out of a situation with more power, just add throttle and get out easy with more than 200HP. Every 200 to 250 hours change the oil filter and oil and fly for another 250 hours.

    If you don't want to build the engine yourself then you could buy one, take a look at this video of the GSXR1100 engine converted by VIJA for aircraft use. The engine is 155HP constant and has a turbo for high altitude flight, it is capable of more power but is blocked by the company for longer and sustainable use.

    Jacques Trincal - Vija Aircraft Engines - Blois 2012 - YouTube

    They could have made the turbo a bit better and lighter but in time they probably will, the engine is around 90kg with oil and everything else needed for flying. If you need more power and lighter weight, you'll most probably have to do all modifications yourself, or find some company that tunes engines like RPE (Radical Performance Engines) or HE (Heartly Enterprises). If you would consult an aerotech engineer and a aircraft mechanic they could instruct them about all the changes necessary for flying. Test the engine first in some rig during the break in period and after that put it in an aircraft that was flying with an engine of similar mass but less power. After 50 hours of flying you'll know that you can count on that engine.
     
  17. Dec 17, 2012 #157

    TinBender

    TinBender

    TinBender

    Well-Known Member

    Joined:
    Mar 4, 2010
    Messages:
    218
    Likes Received:
    53
    Location:
    Charlotte, NC, USA
    Scimitar blades are efficient, in part, because they are quiet. A new C-130 is almost silent from a surprisingly short distance if it's taxiing directly toward or away from you. When I was in the service, there was a designated smoking area barely fifty feet off the wing tip. The old paddle blades would make you abandon your cigarette and go inside if you didn't have over-ear protection. After the switch to the J model, we could smoke and carry on a conversation just by raising our voices.

    This is the reason the un-ducted fans being studied by industry have scimitar shape. Noise abatement is serious business in the commercial fleet.
     
  18. Dec 17, 2012 #158

    autoreply

    autoreply

    autoreply

    Moderator

    Joined:
    Jul 8, 2009
    Messages:
    10,732
    Likes Received:
    2,544
    Location:
    Rotterdam, Netherlands
    If you roughly double the torque the engine produces (otherwise it won't make that power at 6000 rpm), it'll break down in minutes. These are drag racing settings, not to mention that the fuel consumption will be appropriate for a drag racing engine too..
    Not at all. Boxers are used for one primary reason in motorcycles; a center of gravity that's a lot lower than any other type of engine, though the weight is indeed slightly higher. Boxers stopped being troublesome about 4 decades ago...



    @ Detego, are you familiar with the Smart engine of the Track diesel bike?
     
    Detego likes this.
  19. Dec 17, 2012 #159

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America


    I don't support 1906 technology at 2666 pricing.

    As stated before: I'm not interested in powering the prop directly off the engine. My interest is in an engine that provides
    low cost repairs, low vibration/installation, low noise dB, and high torque.


    Your looking at ways of reducing aviation fuel costs; I'm looking at ways of eliminating aviation fuel costs.
     
    Last edited: Dec 17, 2012
    Head in the clouds likes this.
  20. Dec 17, 2012 #160

    Detego

    Detego

    Detego

    Well-Known Member

    Joined:
    May 29, 2012
    Messages:
    470
    Likes Received:
    105
    Location:
    North America

    Nope; but I love it when you talk dirty to me!

    Thx for the information.
     

Share This Page



arrow_white