Light Touring Amphibian - LTA-9

Discussion in 'Bush / Float flying' started by Woodenwings, May 12, 2019.

Help Support HomeBuiltAirplanes Forum by donating:

  1. May 12, 2019 #1

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
    I have been thrashing away for over 10yrs (on-and-off) on my own design. It uses the LSA amphibian specifications as a guide but will be made as an amateur-built (experimental) to allow me more artistic licence.

    Aircraft Mission:

    Just for me....not a commercial venture...unless someone buys the design from me! I want to go places close to home that are on or near the water. Flights of Approx 3Hrs return expected. I want to see, smell and feel as much of the flight as is possible. Getting wet is not a concern. keeping the passenger dry is more important (because they are often not as passionate about all that "feeling" stuff as me). The design may be retrofitted for range/duration by adding gas and engines (designing with this in mind for the possibility of an epic cross-Canada tour...maybe!).

    I am about 10yrs away from having this accomplished - taking my time - i enjoy the design process immensely. I love talking to other people who have made their own designs. Not too interested in having "what-if" conversations or unproductive discussions. I'm also not into social media. please don't post my stuff on social media. let me post my own work as i see fit please!

    The philosophy of the design is:
    1. Designed cockpit-out.
    2. Simple, traditional, proven design solutions
    3. Simple, traditional & proven materials
    4. Emphasis on visibility and safety, then comfort.
    5. Limited use of composites (i hate working with them and they are environmentally troublesome)
    6. Electric - the ability to move props wider, and to reverse them simply is of great interest ( i have spent hours working with Rotax, HKS and Verner layouts). Verners is my fav. for a petrol alternative.
    7. Cockpit: i love simple well laid-out interiors of cars/boats/whatever. I find traditional cockpits like a Cessna 150/172 Etc. to be loathsome. I find the desire to make aircraft interiors look like cars a waste of time. Something smaller, more to the point and not in my way is ideal. increasing the tactility of the cockpit interests me a lot. i want to reach for everything and know it is in reach. I want to teach my children to fly and having dual controls makes sense. Everything needs to be water resistant or tolerant (freshwater). Electric trim.
    8. Undercarriage: I continue to be close to omitting the undercarriage all together. It would save a lot of weight and simplify my life a lot (as a designer/builder). But the first time i want to get the thing up on a beach to inspect the hull for damage or for the reassurance that it won't be gone in the morning will probably justify the complexity and expense in time and money. Having decided to add retractable gear...i want the simplicity of the See-bee without the drag....and i want tricycle gear for a variety of reasons (i love taildraggers...it started as one). Mechanical an/or electrical actuation. There is not really room in the cockpit for manual retraction - the tandem arrangement also complicates this - electric with no backup is probably the best compromise. I have my eye on some servos for the job. Suspension is elastomeric. It will be a little stiff, but underinflated tires will be used to help with beaching...and shock absorption. the gear will be strong enough for terrestrial use but i anticipate using it for launching and beaching mostly. i want to be on the water.
    9. Wing: High-Lift, non-laminar flow wing made of AL. I am in-love with wooden aircraft's smooth surfaces and ultra-rigid wings....but i was having a hard time finding suppliers and adequate storage for materials during construction (a place to put bulk orders). So i have chosen AL ...will have to change my profile name....na! The design used to have flaps....but they have been deleted in favour of simplicity. i have added area instead. Space will be made in the wing to facilitate baggage, extra batteries and fuel tanks. retrofitting for gas engines or for a hybrid system should be prudent. A folding wing will allow the kite to live up to it's mission of being trailered from my driveway to lake Ontario (300m). at present this is a substantial design challenge. I might need some help. or just a lot more time! The wing was a hershey-bar, now it is tapered for several reasons. I have access to CNC so cutting out lots of different wing-ribs and their forms is not a problem. i like the flying qualities of a tapered wing. it also helps with loading. there is very minimal washout at the tips. the airfoil is the same from root to tip.
    10. Fuselage: Steel Tube, Plywood, Fabric and composites....as Reqd. I like steel cages...especially when the entire mass of the plane is behind me. i want to walk away from a prang.
    11. Hull: im very interested in the designs that came about at the very tail end of the flying boat era. the Supermarine Gull, Martin designs and the integration of these concepts and forms into the Shinmaywa us-1 & 2 deep-V designs. I have modified the basic shape for my purposes. the addition of a ski-surface on the bottom to allow a forgiving first contact combined with a deep-v profile and spray suppression skirt were introduced at the onset of the design. There are so many great concepts already in existance - incorperating them into one simple form has been an intellectual treat (i use the word intellectual lightly!).
    12. Propulsion: options still fill this space but the feeling now is towards the MGM Compro offerings. Currently in discussions with them (very early stages). I have lots to learn about these systems beyond what i already know. Dealing with 800VDC is probably going to be touchy in aquatic conditions.
    13. Extras: i love lighting and will probably have to add some cracking LED lights for .... intimidating shipping. Dedicated action camera locations will be added for documenting flights like flightchops does.
    14. Stowage - Entry/Exit: the front seat is like a kayak - the rear is like a champ or cub. Light baggage can be placed behind the rear seat (weight and balance permitting). Most storage will be in the wings.
    15. Avionics: I like open source philosophy - i will have basic steam gauges and some arduino/raspberry-pi based digital systems. there is lots of progress in this area at the moment. i'm keeping my eye on it. currently i have an android tablet shown. i like moving maps. I am even considering making a series of servo actuated simulated steam gauges like the sim-nerds do. some are awesome and it give me the chance to get very individualistic.
    16. Livery: i can't wait to get to this phase - but as it is completely irrelevant - i will just muck about in renderings. expect to see lots of variation in colours and i feel them out. Don't be surprised if the final paint scheem seems very RCAF or RAF-Costal command. It's a boyhood thing! I like D-Day stripes too!
    17. CADD - everything is in 3D.
     
    Vlad likes this.
  2. May 12, 2019 #2

    cluttonfred

    cluttonfred

    cluttonfred

    Well-Known Member

    Joined:
    Feb 13, 2010
    Messages:
    6,350
    Likes Received:
    2,214
    Location:
    World traveler
    Sounds like a lot of fun. We had some discussions about the Shavrov Sh-2 a few years ago and a Russian member of the forum that was building a replica. I think that same parasol-wing, tractor-engine layout that goes back to the Dornier Libelle would be a good configuration for this sort of project as it makes it easy to put the pilot and passenger in the hull and fuel tank up in the wing all very close to the CG for minimal weight and balance issues. The Shavrov had-cranked landing gear is about as simple as it gets and I think you could replicate the mechanism easily using sailboat hardware and low-stretch rope.

    restored Shavrov Sh-2.jpg restored Dornier Libelle.jpeg
     
  3. May 12, 2019 #3

    Riggerrob

    Riggerrob

    Riggerrob

    Well-Known Member

    Joined:
    Sep 9, 2014
    Messages:
    1,136
    Likes Received:
    311
    Location:
    Canada
    A man after my own heart!

    As for landing gear ..... my sketches try to eliminate submerged wheel wells for two reasons.
    First, they tend to fill with (heavy) water and require additional drains. Note the complex main wheel well drains on Grumman Mallard.

    Secondly, traditional nose wheel well doors are fragile and exposed to plenty of pounding during take-off. See the vintage Catalina crash in England a decade or so ago. A corroded door linkage allowed a door to open, which allowed water to enter a nose wheel well - during landing - which caved in a corroded bulkhead, which allowed in too much water, which sank the charming old girl. Sad!

    To that end, I would start with an Aerocet or Wipline nose-wheel. Aerocet nosewheels are lighter.

    To that end, also consider the main landing gear legs on the first Spencer/Republic Seabee prototype, where they hinged up into the fuselage sides and wheels were semi-submerged in flight.

    My studies favour a parasol wing like the Shavrov or Dornier Libelle because they are easier to dock at marinas.
    Sponsons provide plenty of storage space for main wheels, fuel, etc.
    My sketches include operating at two different take-off weights. It would allow full fuel and baggage when taking off from an asphalt runway near sea level, but reduced weight when taking off from lakes high in the mountains.To that end, fuel would ride in three separate sets of tanks. A header tank - in the engine nacelle - would contain an hour’s worth of fuel and warning lights. Main fuel would ride in (parasol) wing root tanks. Finally, ferry fuel rides in sponson tanks. Ferry fuel tanks would only be filled at low density altitudes (sea level).
    Sponsons might even hold baggage, especially wet baggage.

    Tandem seating eliminates a bunch of airflow problems on the aft cabin.
     
  4. May 13, 2019 #4
  5. May 13, 2019 #5

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
  6. May 13, 2019 #6

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
  7. May 13, 2019 #7
  8. May 13, 2019 #8
  9. May 13, 2019 #9

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
  10. May 13, 2019 #10

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto

    Anything Dornier gets my admiration - My grandfather did have to shoot at one in 1943 with a pistol. so everything Dornier except that one! Said he missed it. ! the libelle was very well liked by all that speak of it. so much so that the searay is hommage to it. but it isn't quite right for me.

    i have had wing design finished. but then i decided to go electric! so i am designig it all over agian (2yrs for the first one!). i am more proficient now. it should take a couple of months.

    Propulsive wing LLC did some CFD for me many years ago related to airflow over windscreens - check it out
    http://www.propulsivewing.com/projects-albatross.shtml
     
  11. May 13, 2019 #11

    Riggerrob

    Riggerrob

    Riggerrob

    Well-Known Member

    Joined:
    Sep 9, 2014
    Messages:
    1,136
    Likes Received:
    311
    Location:
    Canada
    So your wings must fold to 8 or 10 feet for trailering to the lake.

    Is there a limit on folded length?

    I am thinking a flight wing span close to 40', which would fit into an ISO 40 container. That will allow simply pivoting a cantilever plank wing to lay along the fuselage centreline, ala. CV-22 Osprey tilt-rotor or Dornier Stingray 007. External struts can vastly simplify the folding mechanism. ......think Stitts Playmate.

    If you want to fold it to 30' overall length, you will probably need a two or three piece wing, ala. Rutan Skigull. Three piece wings allow you to move the hinge joints out to 8 feet, reducing bending stresses on hinges. Again, external struts can simplify folding mechanisms.
    How much space do you need between those twin tractor propellers? Can you keep the engine nacelle span to less than 8 feet? Ideally you would store all the engine and gasoline weight in the fixed centre-section.

    If you are going full-electric, light-weight electric motors open up several new configurations.
    Maybe electric motors would be light enough to mount on folding outer wing panels.

    You could built a centre-line push-me-pull-you with one electric motor on the rear of the pylon, with the other mounted on the top of the fin. Seawind tried a T-tail mounted engine, but the heavy piston engine forced a very short tail moment arm, deteriorating stability and control. Perhaps a light-weight electric motor would solve that balance problem.

    Even wilder would be a twin tractor propellers mounted on the horizontal tail (beware of spray problems).
     
  12. May 13, 2019 #12

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
    The design in pictures above is fixed...meaning there will be no further design changes except those relating to propulsion and wing folding! Not interested in a shipping container in my garden. Shelter is not a problem. Many boat trailers are made to be as wide as is possible. Approx 100". Boat trailers are inexpensive and perfect for my needs. I want a wing fold that does not require any external change in the machine that could cause water to enter and increase complexity. There are lots of ways of doing it. I have spent lots of time looking at real aircraft. Most are not applicable because they are fighters etc. I also like the fournier approach but it would need to be actuated by a mechanism not by hand on a wing as big as mine. Have a careful look at the renderings. The wings will be connected to the tail for transport. They also need to be folded by one person. The grumman design prevents the wing from hitting the ground as long as the plane stays put on it's gear. I find that people underestimate the amount of work I have done designing the thing. I'm at the end of the design process not the beginning! If the finances are secure it will get built. The design will wait for the bank I assume!
     
  13. May 14, 2019 #13

    Tiger Tim

    Tiger Tim

    Tiger Tim

    Well-Known Member

    Joined:
    Apr 26, 2013
    Messages:
    2,809
    Likes Received:
    1,561
    Location:
    Thunder Bay
    That airplane sure looks like it wants to just be an Air Cam with a hull...
     
    Dillpickle likes this.
  14. May 14, 2019 #14

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
    If anyone wants to discuss further with me; PM me. No time for unproductive banter.
     
  15. May 15, 2019 #15

    Riggerrob

    Riggerrob

    Riggerrob

    Well-Known Member

    Joined:
    Sep 9, 2014
    Messages:
    1,136
    Likes Received:
    311
    Location:
    Canada
    Handsome sketches dear woodenwings!

    Was your mother scared by a PBY Catalina while you were in her womb?
    Hah!
    Hah!

    That twin-engines configuration lends itself easily to powered docking.

    Relax.
    We were not trying to change your basic configuration. Your basic configuration is sound ..... as proved by half of the total flying boats being Catalinas. Catalinas are well-respected. Even Burt Rutan copied some of the Skigull configuration from a Catalina.

    Nor are we trying to tell you to install an ISO shipping container in your back garden. The primary reason I mentioned ISO shipping containers was a challenge to reduce folded dimensions to 8 feet by 8 feet .... for road travel.
    The second reason was to limit size, to keep it light and prevent it from ballooning into an F-111 sized monstrosity. ISO 20 proved tight for a single-seater and irrelevant for two-seaters. Your LTA-1 will probably end up between 30 and 40 feet long when folded.
    One way to simplify horizontal tail folding is adding an external/diagonal strut and pivoting it to lay along the fuselage centre-line. I even sketched an assymetric horizontal tail plane to further ease folding an ultra-light. Assymetric is probably too radical for you, but the concept is still valid for trailering a light touring amphibian.
     
  16. May 16, 2019 #16

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
    Perhaps my expectations were outdated - When i joined this website in 2006 it seemed much more populated by engineers and pilots than by people trying to regurgitate PBS documentary titbits and empty opinions. As long as conversation isn't going down that rabbit hole i'm happy enough to chat. i am genuinely interested in other peoples experience driven opinion. i'm sure i'm not the only one to feel this way.

    I felt it necessary to spell out my situation. otherwise i will have to endure endless "what-if" or "yu should-have" comments from people with no skin in the game. no thanks!

    Design convention happens when simple solutions become understood to be the standard - my design is no different. i'm just a guy trying to design and build a plane from scratch. the puzzle is my pleasure.

    The smallest possible folded form is ideal.....but i want to find the sweet spot. I want to keep the plane at home so i can work on it as much as possible. I also don't want to hang out at the airport all day....or ever. paying fees is silly. My uncontrolled strip is lake Ontario on a calm day. The nearby boat launch is all i need. I could taxi from my driveway to the lake if i had a tax-disk, horn and indicators! might cause a scene.

    The Arado Ar-231 is of great interest (asymmetric origins of your design i imagine). It isn't my cup of tea. but a respectable achievement.

    I did not set out to emulate the Supermarine Seagull ASR-1 (Type 381): https://en.wikipedia.org/wiki/Supermarine_Seagull_(1948)
    But a similar set of design goals has led to a similar looking machine! A good looking machine it is! I have a catalina near my house that i have looked at a lot. i honestly didn't copy any of its features. But it is a good machine and i enjoy watching it flying around on one engine in the summer. We also have a Lancaster, spitfires, hurricanes and others in the same hanger. Some days the airshow seems overhead the garden if the weather is fair.

    I am looking for the most elegant solution possible for one-person operation. if it fits in and ISO-20 cool! it is just too tight in height. custom trailers are a piece-of-piss compared to the plane.
     
    Vlad likes this.
  17. May 16, 2019 #17

    Victor Bravo

    Victor Bravo

    Victor Bravo

    Well-Known Member

    Joined:
    Jul 30, 2014
    Messages:
    5,803
    Likes Received:
    4,649
    Location:
    KWHP, Los Angeles CA, USA
    I hope this is not unproductive banter, but can you explain why the engines are further outboard on the wings than it would seem is necessary? Seems to me this would worsen an already difficult situation with one engine out. If I recall, the PBY had the engines set as close in to the fuselage as possible for this reason.
     
  18. May 16, 2019 #18

    Woodenwings

    Woodenwings

    Woodenwings

    Well-Known Member

    Joined:
    Aug 2, 2006
    Messages:
    164
    Likes Received:
    5
    Location:
    Toronto
    :) understood!

    The wide spacing and lack of outward offset centre lines is because it is electric. I am trying to capitalize on the reliability and flexibility of motors. Engines would be relocated close together...like a pby...and would be pushers to get prop disk away from flash. The width of electric will help on the water by offering better differential steering and to keep spray away from props.
     
  19. May 16, 2019 #19

    BJC

    BJC

    BJC

    Well-Known Member

    Joined:
    Oct 7, 2013
    Messages:
    9,084
    Likes Received:
    5,893
    Location:
    97FL, Florida, USA
    Is there enough experience with electric motors used for aircraft propulsion to draw conclusions about their reliability?

    You mentioned a later version with engines; a Verner radial version would be very pleasing aesthetically and audibly.

    Can it be launched with the wings folded, or will that put the CG too far back?

    It is good to see a design study / proposed project that has a realistic time schedule. But I wish that it could be shorter, because I am eager to see it in action.


    BJC
     
  20. May 17, 2019 #20

    Riggerrob

    Riggerrob

    Riggerrob

    Well-Known Member

    Joined:
    Sep 9, 2014
    Messages:
    1,136
    Likes Received:
    311
    Location:
    Canada
    Warning!
    Thread drift!

    He could launch with wings folded aft as long as there was sufficient reserve buoyancy in the aft fuselage/hull.
    Mind you that extra volume increases weight .... a long way from the C.ofG. ....
     

Share This Page

arrow_white