Guest Maj Millard Posted May 31, 2010 Posted May 31, 2010 I have started to design a new aircraft. (My second from scratch) It started yesterday when I spotted a wedgetail eagle soaring above the trees, whilst I was driving. It reminded me instantly of the great Lazair design which just begs to be recreated, as it is the closest thing I have ever flown that emulates a bird of prey. For the next few hours my feble mind worked overtime with structural and design details, and by early evening I was at the kitchen table drawing, to my wifes' obvious displeasure!.... So far the details are as below. I will also build a small balsa model to streamline and trouble-shoot the design further, which I can then photograph and post on this site. Wing: Of course the beautifull and highly efficent Lazair wing, modified for additional strength, fuel capacity, and the addition of large flaps which can be reflexed in cruise. Wings will effectivly be a bit shorter overall, for better manouvering and handling in high winds for landings etc. Double streamlined wing struts for strength. Upturned tips like the Lazair of course. Wings will be double spar, all alum, with inner cable bracing as required. Fuselage: 2 place seating slightly staggered, ala Rutan designs to keep the fuselage as narrow as possible, but still wide enough to be comfortable for long Xcountrys. As streamlined a fuselage as possible, and welded chromemoly throughout, with helicopter-style full lexan sourround, for absolute visability. The circular tailboom will be very similiar to, and attached the same as on a R22 or 44 helicopter IE: monococue circular alum structure, bolted to the fuselage structure. the overall fuselage length will be much longer than the original single-seat design(below). The new design will be quite different to the original in the photos, with the wings and tail being the most similiar in appearance. Engine: Unlike the original Lazair it will be a single-engined, tractor style, with either an 80 or 100 HP 912, with small dia 3-blade prop, and very streamlined cowls like on the CTs. The wing spars will however be built to accept a twin engine set-up, with smaller Horsepower engines down the road if desired. Going twin at this time is just too hard with current rules. Tail: The classic Lazair inverted-V, which is the most efficient tail, and is what soaring birds have, which is probabily why the Lazair flys like a big eagle. This will also scare away all the tire-kicking gang, and will allow the design to appeal to the real purist, looking for an ultimatly efficient, and highly capable, cross-country aircraft design. Undercarrage: Tail-dragger design, with a retractable tail-wheel on a strut, between the two tail surfaces. Should the tail wheel not deploy, the twin tails will be capable of handling a slow landing with small skids. Main gear will have streamlined legs, will be short, and further foward than normal, with streamlined wheel spats. I would like the main gear legs to be manually retractable down the road, directly straight up and down, but the prototype will be fixed. Design goals: Plan sets will be offered once aircraft has flown, with possible kit sets available. Not designed for mass market production, as the inverted V tail will not appeal to all but the design purist. Aircraft will be highly efficient in cruise, with a targeted 100 Kt + min cruise speed. It will be a STOL aircraft, with large landing flaps, and rugged landing gear. Take-off will be very short, with good load carrying ability IE: two people, min 120 lts fuel, and good baggage. Aircraft will be built very strong ala the Lightwing, for excellent turbulance penetration speeds. The design should be beautifull to view, both on the ground, and in flight. The design will be appealing in a European style, because of the obviously efficient, and simplistic design lines. That's the dream for now !...Model to follow.......................................................................................................Maj...
monty Posted May 31, 2010 Posted May 31, 2010 Sounds pretty good Maj, I will follow your post with great interest and come to T/Ville to see it when finished. Look forward to the seeing the plans. Sounds OK to me! Monty
Guest Maj Millard Posted May 31, 2010 Posted May 31, 2010 Thanks Monty, I have no idea when I'll produce a prototype in this financal climate ! It'll be step by step, with plans drawn, model and then cutting metal. I'll be happy to just produce plans at this point, at least then somebody may pull it all together down the road. I have designed, built ,and flown one original aircraft before successfully, so if I can get my hands on materials, it'll happen..........................................................................................Maj..
pudestcon Posted May 31, 2010 Posted May 31, 2010 Well good luck with the design and ultimate build project Maj, Can't wait to see the photos and drawings as you progress. Pud
Tomo Posted May 31, 2010 Posted May 31, 2010 Onya Ross! I wondered when you'd dig out the pencil and drawing papers again... good to hear :thumb_up: Look forward to seeing the model
Yenn Posted May 31, 2010 Posted May 31, 2010 The thing that I notice first with a Wedgetail eagle is the 45 deg dihedral. I hope you don't try to copy that. They are great flyers, but take off is not very impressive.
Guest ozzie Posted May 31, 2010 Posted May 31, 2010 Go electric. Yenn i've never had a problem of any type with the inverted v tail on the lazair. except for tripping over the low set brace wires. With the original longer dimesions when you landed on the stall the tail would touch down first. now with the shorter version about 6 inches the tail will touch down just as the mains hit. The inverted tail does not suffer from 'hunting' like a upright v tail. And is out of the turbulance or the wing in the stall. ozzie
Guest Maj Millard Posted May 31, 2010 Posted May 31, 2010 Yenn thanks for your input. I would consider 45deg of dihedral to be excessive on any aircraft, and even though the Wedgee has the choice to use that amount at times, mostlly they cruise along at altitude with wings almost level, using I would guess at around 5 deg or so. Most aircraft will have 2-5 deg of dihedral (some more, some none, some with anhedral). 2 deg will give you the stability of the dihedral effect, and more possibly means more stability, to a point of diminishing return. It just depends on the type of wing and aircraft. I'm imagining at this time probabily around 3-4 deg on my design..........................................Maj...
Guest ozzie Posted June 1, 2010 Posted June 1, 2010 Oops i did not have my reading glasses on when i read the post by Yenn completly miss read that. sheesh what a putz i is
Deskpilot Posted June 1, 2010 Posted June 1, 2010 Good on ya Maj, nice to have another dreamer in the forum. I think your design is appealing and will be more acceptable than mine. It will certainly be in the air before mine as well. Keep us informed won't you? BTW, will you be completing the design in pencil or can you use CAD and a 3D modeler?
sain Posted June 1, 2010 Posted June 1, 2010 Sounds good major - a beefed up, heavier, faster lazair. I'm not familair with the airfoil (or wing really) on the Lazair - its a custom designed airfoil isn't? My understanding was that the wing had been designed for good very low speed handling. Is that still one of your design goals? *edit* damn but i'm an idiot. I should have read your design goals more carefully in the first place - it would have answered the question for me.
frank marriott Posted June 1, 2010 Posted June 1, 2010 Ross Tried to PM you but your mail box is over the limit, Frank
Yenn Posted June 1, 2010 Posted June 1, 2010 Hey Maj. You must have a different Wedgie up there, ours seem to spend most of their time with the wings well up. As for take off, I nearly clobbered one who had trouble getting up from his road kill, he kicked off the bonnet and again off the roof of my landcruiser. I look forward to seeing more of the design.
Guest Maj Millard Posted June 4, 2010 Posted June 4, 2010 Thanks Wigg, Deskpilot, Currently working on clean sheets of white paper with pencil and rubber, worked for Rutan didn't it ?.........I haven't got around to Cad or 3D yet. I do have a friend who is fast on CAD, I may give him my drawings to put on CAD during his slow days. I don't know if mine will be in the air first. If I had 10 grand I reckon I could do it in maybe 3-4 months working fulltime. It's all in my head already, I just need to put it on paper. Sain, Frankly couldn't tell you what the airfoil is, even though I have flown it, haven't got that far yet. You could be correct, it may be a custom airfoil. The Lazair was an outgrowth of a thing called the "Superfloater" which was an unpowered glider. Ozzie might know, or Pylon 500. It did of course have excellent low speed handling, and good climb as I recall also. I am very fond of the basic Clark Y airfoil but this one may have to be a bit more exotic. I do want this aircraft to have good low speed handling and landing, but it may be achieved with the large flaps. Yenn, Your not watching Sea Eagles down there are you mate ?..................Maj..
Guest ozzie Posted June 4, 2010 Posted June 4, 2010 Dale Kramer who designed the Lazair used a custom airfoil section. It is very stable and and does not give good climb rate until until it is just about on the stall speed. Bit un nerving the first few times you fly it. 19/20mph almost laying on your back gives around 150fpm on 70lbs thrust max weight 375lb. Dale has never given away his secrets on anything he has designed. he is also very well respected amongst the US and Canadian sailplane fraternity. Ozzie
Guest Maj Millard Posted June 11, 2010 Posted June 11, 2010 Design work is going well, I stayed out of the bar at Shute Harbour at least three nights this week, and instead worked on plans and model. I now have a pre-weld fuselage model completed, and a side view detailed drawing of the whole aircraft. No apparent major problems so far, and I am leaving the best part, the main wing, till last. Can't wait ! as it will be built up structurally correct, and ready to fly on the hand launched model. I will post photos sometime this weekend of both the above, for comment. I have purchased Balsa for the proof-of-concept hand launched model which will hopefully show that I am on the right track. I also have procured an R22 tailboom that has slight, but reparable damage, and should be fine for the prototype, plus will save a lot of time in manufacture. I have pretty much settled on the name 'Millard Wedgetail' after watching another Wedgee fly this week, but hey, whats' in a name ?. Having worked on and flown a few ULs, I find that I can borrow the best from each, and streamline the design, plus hopefully the manufacturing process. I want this aircraft to be at least as strong as the Lightwing, with similiar take-off/landing capabilities, but with a much faster cruise speed. It also has to be easy and fast to build, with a minimum of parts if possible. KISS theory-(Keep it simple stupid). TAR method-(that's about right.) And I don't believe in re-inventing the wheel, if it has already been perfected !........Maj...
pudestcon Posted June 11, 2010 Posted June 11, 2010 Jeez Maj!! You don't let the grass grow under your feet eh? And the sacrifice:thumb_up: Magnificent! I look forward to seeing you progress Pud
Guest Maj Millard Posted June 11, 2010 Posted June 11, 2010 Thanks Pud, The sacrifice was the hardest part !....I'm running hot on this one, and really want to get the model happening quick, as I think it will be pretty slick, and I am interested in some feedback. I procured the tailboom within a week of coming up with the idea, so I took that as being a major good omen !...................................................................................Maj..
Guest Maj Millard Posted June 11, 2010 Posted June 11, 2010 Preliminary work so far,.............................
Guest studentbiggles Posted June 11, 2010 Posted June 11, 2010 Maj.......God your a very "cleaver cookie"...I truly admire your design concept!....Would be very interested in what you have in mind for the interior design and layout of the cockpit for it is a passion of mine and what I do in my own business as in "Retro" refits not only for humans but for lots of other jobs out side this sphere and I would love to refit or help design an A/C interior:keen: ....When ever I jump in someones A/C the first thing that comes to mind is...."How and what would I do to "Revamp" this lovely machine"!!!! Good luck with your new A/C design Fly Safe Alley
MrH Posted June 11, 2010 Posted June 11, 2010 Hey Maj, I like the look of it :thumb_up: The seat looks a way back though Cheers H
blueshed Posted June 11, 2010 Posted June 11, 2010 Hi Maj Looks great! Love the concept! will you have full length flaperons, as per Foxbat, will you employ negative flap to assist with top end speed, maybe even a trim able tailplane to decrease drag in the cruise. Oop's just flexing the grey matter, not trying to move in!
Guest Maj Millard Posted June 12, 2010 Posted June 12, 2010 Thanks for all your kind comments today. ALLEY, I'm fond of good cockpit ergonomics also, things have to work well when you need them. Nothing worse than a messy set-up especially if your in your 3rd or 4th hour of flight, thats when it really gets you. I have learnt a lot recently from several aircraft. for instance the Lightwing has good cabin size, is comfortable, and the seats are good in a crash, but like many, some shortcomings of course. Really like the fuel capacity of the Savannah,(150lts useable), and the 10 ltr fuel reserve tank. Also the Y yoke works well, and is comfortable to use. We are at a stage now where we can put a little style and comfort into our UL cockpits, for those long legs. Mr H...Yes I'm looking at the seat position also, remember it's a two seater, side by side, and the tail only has two surfaces instead of the usual three, so should be a bit lighter than normal. Early times yet, things still changeable. Blueshed (love that name)...I understand the advantages of the full length flaperons as I have flown the Kitfox, and also the savannah has them, to good advantage. And of course the Foxbat uses them well also. Currently will go with long (3/4) flaps with separate ailerons ALA Cessna Caravan, as it also has a highly loaded wing as I suspect mine may be . Yes I definitly will have reflex flap for cruise as it is one of the few 'free rides' in aircraft design and works so well also. Not sure about a trimable tailplane at this stage..................Maj...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now