Well, what do you know?

[Deskpilot]

I've seem to have made the grade in some one elses mind. Check out the following link and see my design.............in America.

 

http://jdasolutions.aero/blog/acting-faa-administrator-confirms-that-part-23-arc-is-going-to-propose-new-creative-aircraft-certification-process/

 

 

[turboplanner]

Your drawing, or just a design copy?

 

 

[Deskpilot]

The 'Drawing', as most people refer to it as, is a 2D export of my SketchUp model. So yes, it's my design. In fact, it's my first design started over 8 years ago but never finished due to, at the time, not believing in myself. I might still go back to it, if I live long enough

 

 

[Old Koreelah]

...if I live long enough

Ahhh, DP that's the problem we all face.

Can we see your original design? It appears the tail boom is co-axial with the prop.

 

 

[ayavner]

Ahhh, DP that's the problem we all face.Can we see your original design? It appears the tail boom is co-axial with the prop.

That, and "not believing in yourself". Good onya Doug!

 

 

[Deskpilot]

Ahhh, DP that's the problem we all face.Can we see your original design? It appears the tail boom is co-axial with the prop.

Would you believe, Sod's Law has it that I deleted the original model and only these 2 images remain.

 

 

However, I do still have the follow on models and here are a few images from those.

 

Very first model when I didn't know much about SketchUp

 

A friends impression using a different CD software package.

 

Trial, using body components from other designs, and an inverted Y tail-plane.

 

A High engine variation

 

Further development of the Pod.

 

An early attempt at mounting the bearings on the fuselage and not on the boom.

 

To ovoid the use of very big and heavy, ring bearings, I moved on to the Bearing Cradle. This now needs to be updated, or redesigned by a qualified engineer.

 

This design is still in my mind but I can only work on one at a time.

 

 

 

 

 

 

 

 

 

[Old Koreelah]

Doug you have some revolutionary design ideas! Your drawings are impressive too. The prop blast over the three-angle empenage should ensure responsive handling.

 

I presume a nose-mounted prop helps short take-offs by accelerating air over the wing, but I like the visibility of a forward cockpit.

 

 

[Deskpilot]

Thanks OK. I went to the inverted Y purely because a crossbow Bolt has 3 fletch's (yes I know some only have 2 but you can't control a plane with only a horizontal stabilizer). It does make anchoring then harder that the original crucifix but them's the breaks. I have been told that an inverted V would be more than sufficient but I don't like it aesthetically.

 

As for my 'revolutionary designs/thoughts, what do you think of this............will it work?

 

 

Will the slipstream blow/push the membrane into a nice curve? I'm thinking of trying it to cover BIG gaps on simple flight control surfaces.

 

 

[Old Koreelah]

what do you think of this............will it work?[ATTACH=full]19983[/ATTACH]

Will the slipstream blow/push the membrane into a nice curve? I'm thinking of trying it to cover BIG gaps on simple flight control surfaces.

I have been trying to do something similar: bridge the large gaps on my Jodel. The Mylar used by sailplane people is too narrow (I need 60mm) and thin lexan is too rigid. Most Jodel builders just install fabric inside the gap to stop air leaking up thru the gap, but I wanted to get more streamlining... Beware. Gap seals have come adrift in flight, creating turbulence over control surfaces. We could make a poofteenth improvement in efficiency and crash the plane!

 

 

[facthunter]

Keep it simple. A fellow I flew with who flew Hurricanes in UK in that war, used to say it all went bad after they stopped using wing warping. You don't use a lot of aileron in straight flight and to stop adverse aileron effect, they use frise ailerons that make more drag . Positive and effective control is what you need. Nev

 

 

[geoffreywh]

that's going to be a bugger of a job to change the belt! you'll have to go to a chain?

 

 

[Old Koreelah]

that's going to be a bugger of a job to change the belt! you'll have to go to a chain?

MV August used a row of gears to drive the cams on their legendary bike engines. Perhaps a bit too heavy for us. Keep it simple and light. The Belgian D motor ticks a lot of boxes here. http://m.youtube.com/#/watch?v=wxK_GcZ3RSQ&desktop_uri=%2Fwatch%3Fv%3DwxK_GcZ3RSQ&gl=GB

 

 

[Deskpilot]

that's going to be a bugger of a job to change the belt! you'll have to go to a chain?

Not really. The boom/empennage assembly is removed in one piece. It is located in internal rings within the pod and above the engine. A simple locating/locking pin(s) will hold it in place. Tail controls would be either quick release in-line telex connectors or a 'plate to plate system used in other removable wing types. Remove cowlings, remove prop. Slacken belt tensioner(s) and slip belts off lower pulley(s). Lift over hub and remove. Too easy.(I'd hope)

 

Obviously, a special prop hub would have to be made out of carbon fiber together with inbuilt ground adjustability. This would probably be the most expensive part of the exercise.

 

Nev, yes, KISS is important and with the exception of the drive system, I'd keep this plane 'simple'. My intention was to use a more streamlined set of flaperons, with possibly 3 sections when flaps are deployed and drooped. The end section being used a the aileron. Complicated perhaps, but I haven't spent much time on examining the design. If I can make it work (simply)I will use the system on my current design. Before anyone asks.............why NOT. See my signature.

 

 

[Old Koreelah]

...it all went bad after they stopped using wing warping...Nev

Many design ideas abandoned years ago are worth a second look, given recent improvements in materials and electronic control systems. The D Motor is one good example. Perhaps wing warping of flexible carbon fibre structures should be tried.

 

 

[Marty_d]

Wing warping is not dead! Just has a bigger name now.

 

http://en.wikipedia.org/wiki/Boeing_X-53_Active_Aeroelastic_Wing

 

 

[AVOCET]

Hi there , are you still working on this boom prop idea , I've been out of the loop for a while ,

 

I found this concept from the late 60s of a boom prop design and was one of the designs that inspired the Avocet .

 

I have worked out how to do the boom prop & it looks very similar , I also looked at large ring ball bearings but didn't like the weight or maintaince issues

 

Have alook at this concept by Paul MacCready

 

igot from an old Smithsonian book

 

 

Cheers ,Mike Sharples

 

 

[Deskpilot]

Hi Mike. Yes I still think about this design and occasionally come up with an improvement idea. The weight of the bearing and prop hub were my main issues but have since reversed the way in which I'd do it. Instead of having a bearing inside the prop assembly, I've moved to a set of bearings outside the hub and created a revolving cradle.

 

 

Belt tension holds the hub onto the cradle. A removable top bearing set could be fitted but is more weight. As you can see, there is no contact between Boom assy and hub assy so removal of the boom is dead easy. There must be sufficient slack in the belt to allow for them to be lifted out of their slots and the hub moved aft for removal. This might lead to some problems with the tensioners though. Haven't thought that far ahead.

 

 

Ignore the scalloped boom, just an idea to provide space for the controls to run inside boom skin (plastic drain pipe) Dependent upon materials used, a 3 bearing set would be possible. Assuming a carbon fibre hub, metal inserts would have to be embedded as running surfaces.

 

None of my designs are patented. Good luck top anyone building on them. Would appreciate some acknowledgement though.

 

 

[AVOCET]

I googeled " boom prop " and there's a guy in America who's made a similar assembly and used a 3D printer to make it . It's with a look .i don't know how to set up a link so you'll have to google it

 

Cheers & thanks

 

Mike .

 

 

[Deskpilot]

Avocet you've done it now. Spent yesterday afternoon reworking my cradle, spent a couple of hours thinking about thrust bearings (not in current design) before I finally went to sleep, and woke up this morning with it still on my mind. If I had the money now, I'd be torn as to do I build my simple twin prop pusher or return to my first off ever design, the Boom-prop?

 

 

[Old Koreelah]

Keep up the good work, DP. Great to see revolutionary designs.

 

Why not throw out everything and start again? (No, not Year Zero like Pol Pot)

 

The early aviation pioneers were limited by the materials and power plants available 100 or more years ago.

 

If humans were to fly for the first time now, with the technology available today, what would their craft be like?

 

A lot of research has been done on flapping wings; nature is so much more efficient than man- made designs. Why should our airfoil be limited to level flight, when one adaptable structure could lift, propel, hover, land and then fold up?

 

 

[Deskpilot]

A lot of research has been done on flapping wings; nature is so much more efficient than man- made designs. Why should our airfoil be limited to level flight, when one adaptable structure could lift, propel, hover, land and then fold up?

I doubt that man will ever be able to imitate that.

 

As for keeping it up................................lol. Oh, you're referring to 'the good work" Sorry.

 

I need an experienced design engineer to do the cradle. My attempts to incorporate thrust bearing(fore and aft) are somewhat childish and probably non workable.

 

 

[AVOCET]

I doubt that man will ever be able to imitate that.As for keeping it up................................lol. Oh, you're referring to 'the good work" Sorry.

 

I need an experienced design engineer to do the cradle. My attempts to incorporate thrust bearing(fore and aft) are somewhat childish and probably non workable.

He's right , keep it up , aviation needs thinkers as well as doers , it's a good Idea and would not be that hard to work out the stresses & loads for a given prop size / boom size ,& such .(I know the "such"is the tricky bit)

 

The thrust bearing for a crank shaft isnt that difficult to reproduce on your boom , chech out the jabiru manual ,( that'll Probly keep you up tonight , sorry,... not) .whatever you do you'll have to incorporate some form of lubrication IDE imagine ?

 

My Son has designed a planetary gearbox for contra rotating props that mounts on a boom . He has a working virtual modle that has impressed his mech engineer uncle ( believe me that sayin something !)we are going to get (build ) a 3 D printer to make the prototype

 

So as soon as the Avocets up & sorted ill be starting on the light weight motor glider.

 

I need something cheep to run &

 

fly / glide around the Flinders on those glorious days .ide really like to go electric , or solar

 

Cheers

 

 

[Deskpilot]

Thanks for your comments Avocet. I appreciate the support. Now, here's some comment on your comments.

 

My prop is not on the boom, it's around it. Therefore, no stress/load calcs needed other than the tailplane itself.

 

As for lubrication, I initially thought that a force fed lube system would be needed but with a bit of afterthought, I think it's possible to get away with high speed, fully sealed and lubricated bearings. These would be running a lot slower than their rated speeds. Cool ram-air could be directed into the cradle to help keeping them comfortable. More important, it would cool the running surface which rests on them.(the hub itself)

 

Contra-rotating props would be the ideal set-up. Weight is the biggest enemy of the required gear-box. Of course, a planetary system would have to be lubricated as you suggest.

 

Not sure what the Jabiru manual would tell me other than what it's fuselage is rated at.

 

I'll post an image of my latest thought when I've finished it.

 

 

[Deskpilot]

Having more probs with my pc so I'll post these images now rather than wait until all the details are there.

 

Boom ready to be slipped through the prop hub.

 

 

Boom will be located by pins , and then 4 over-center clamps will lock it in place. Obviously, the hub assembly, thrust bearing assembly and boom will be hard mounted to the fuselage/chassis whilst the engine will be mounted on anti vib' mounts.

 

Like I said earlier, my thrust bearings assy is somewhat childish but then again, the KISS principle at it's best.