Jump to content

Justin

Members
  • Posts

    62
  • Joined

  • Last visited

  • Days Won

    20

Justin last won the day on April 27 2023

Justin had the most liked content!

1 Follower

Personal Information

  • Real Name (Public)
    Justin
  • Location (Public)
    Sweden

Project/Build Information

  • Plane Type
    Undecided/Undeclared

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

Justin's Achievements

Apprentice

Apprentice (3/14)

  • Reacting Well Rare
  • Dedicated Rare
  • Conversation Starter Rare
  • First Post Rare
  • Collaborator Rare

Recent Badges

39

Reputation

  1. Thanks Anthony, Interesting comment on the helicopter skids. I think the jig is a developing design. The skids and struts are there to add dimensional stability to the formers, but if the spine part is made with aluminium extrusions I could foresee that the skids and struts could be replaced by extruded angle brackets bolted directly to the spine. As the foam planks are added these brackets are removed, to ensure ease of jig extraction from the finished core with the external skin. Hmmm....
  2. Hi Folks, This is progressing, and it is becoming quite a complex assembly, so it is worth making the whole system reusable. I uploaded a CAD update at https://grabcad.com/library/quickie-q2-fuselage-jig-april-26th-2023-1 . It is only the jig. All the previously uploaded planks are unchanged. I foresee that all the formers will be water or laser cut. The new plank layout gives an assembly order of planks that adds dimensional stability to the assembly, and parts of the jig structure can be progressively removed to allow the second and final planking operations. First the upper planks, down to the waist line are added. Then the jig is turned over; possibly on axles from the ends of the spine parts. BTW, the spine is a 4" square aluminium extrusion, with a smaller 2" x 2" tail extrusion. When the assembly is upside down the former support struts at FS146 and FS158 are removed. Then the bottom planks are added. Next; the 'helicopter skids' all the former support struts are removed, and the remaining side planks are added. Then the planks are faired and the skin laminates added. I will work next on how the foam core with the outer skin is separated from the jig formers and spine. The process will be to make the fore - aft fuselage split, and the top and bottom tailcone split. The spine can be extracted, and most formers can be extracted. It looks like the cockpit area formers at FS 53.5, FS63, and FS74, will need to be made in two parts, to enable extraction. After this the internal foam surfaces can be cleaned up and skinned. I still see no need for the main fuselage part to be split at the waist. It will be open at the ends, and where the canopy frame core is cut out. Until the inner skins are added there will be a need for some simple external cradling to ensure accuracy. So... there is some more work to do ! Here are a few pictures.
  3. Just made an update to the CAD files.... https://grabcad.com/library/quickie-q2-fuselage-foam-update-1 It is completely re-planked. A lot of the planks are now simply 2.5" wide. Several do have some tapering. Most are nearly straight. There will be some minor tuning to the planks, but the layout is now good enough that I can return to the jig design.
  4. re:- " They're "in an absurd format" because the decision, before my time, was to convert them to text only so they would be Internet searchable. It would be nice to have them as PDFs (now that PDFs are searchable) and that is on the list of things to improve. I just went through 3 sets of printed copies to select the most scan-worthy issues. " Just a little something I discovered, when saving the newsletters. Using Chrome, I just open the newsletter and hit CTRL-P . Windoze then gives an option to save as PDF.
  5. Well, I don't know. The aircraft fascinates me. Q1 as well. It is such clever design, with a small robust structure.... quite short lifting surfaces.... very easy load paths.... and it is super sleek. If I built one I would use this technique. Kit cores are probably not available secondhand here in the E.U. Mine would be a Q260 ! I would use the UL260i engine. It is a tiny bit lighter than the Revmaster. It is a lot more expensive, but has 97hp, fuel injection and FADEC. I will make the jig design easy for anyone to build. The formers could be mill, water or laser cut MDF 10mm thick. The CAD modeled formers have edges bevelled to the inside of the foam, but they could be cut square, as long as the builder pins the planks on very close to the plank-former contact edge. I have done this in foam boatbuilding. The foam planks strain easily, and need very light fastening pins to constrain them to the jig until the adhesive between the planks sets. The other part that is also probably not available it the LS-1 round canard spar. I don't like it anyway, and would follow the Wieshaar Doyle idea... https://aerobase.weebly.com/ls-1-canard.html
  6. Just a small screenshot update. I am re-planking in a layout that uses mostly parallel sided 2.5" wide planks, with tapering in some places. These would bend in the plane of each plank, as well as around the jig templates, so only the width of the plank is relevant. The planks could be cut pretty much straight, with this new layout. I am inclined to go with 0.5" thickness foam sheet to start with, because something like 0.08" to 0.1" will be faired off. It is likely this core will end up a little heavier than the thermoformed kit core, but I expect the difference in weight would be very small.
  7. Hi Anthony, Thank you for that information. The holes on the 1" grid are probably bleed holes to let resin through to a breather layer when the foam is being vacuum bagged onto a skin in a mould. I forgot to answer your question about flat development of planks. Rhino has a command for this. It will unroll any surface that has 1 degree curvature in one direction; just like a plank has across its width. The surface should have reasonable parameterisation in the other direction, and then this command produces very accurate developments.
  8. Hello Anthony, I do a lot of the CAD work in Rhinoceros, but for detail and assembly work I use my day job Catia. I am considering getting my own Autodesk Inventor license for other projects too. I would be interested in finding out the thickness of the kit shells. It is likely that was an easier way to go, but foam planking is really easy too. I have made a few boats that way.
  9. Hi Folks, I am adding foam planks to the jig now, cut from flat sheet foam. I think some kind of foaming adhesive would be best for bonding these planks. I foresee that I will completely re-plank this to make the planks easier to mark out and cut. CAD files are uploaded here : https://grabcad.com/library/quickie-q2-200-fuselage-foam-jig-wip-1 This is just work in progress
  10. I found the reference to the ground attitude in one of the newsletters.... https://www.quickheads.com/index.php?option=com_content&view=article&id=455:quickie-newsletter-25-page-9&catid=13&Itemid=110
  11. Hi Folks... Well, here is the new Quickie Q2 helicopter ! It is really the bare bones of a fuselage foam core jig concept. This will get another 9 formers in something like 3/8" MDF, arranged on a spine, and braced to the 'helicopter skids'. The entire fuselage would then be planked in H35 Divinycell. I hope this can be found in 1/2" thick sheet, but it is almost impossible to find out if that is available. I would need to 'expand' the complete plank layout. In shibbuilding this is called a 'shell expansion' or 'plank expansion', and in foam it would be nice to avoid planks tapering to zero near the tail. A layout with 'nibbed' ends needs to be devised. I can do this in Rhinoceros. A suitable adhesive to go between the planks is required. It could be dry micro, but there are adhesive available specifically for foam bonding that are as strong as the foam, and as light, and as easy to sand fair. I don't yet know of a suitable one for H series Divinycell. The technique would be to start planking round the sides and bottom, and gradually remove the bracings to the 'skids'. The foam core will reach a stage where it maintains the dimensional stability of the whole core on the spine part alone. This spine part might need to be made of steel tube, but the skids could be wood. All the formers must have polyethylene stapled on their edges to prevent foam core adhesion to them. I foresee that the spine part has bearings at both ends, so the fuselage core could be rotated, once it is dimensionally stable. All pins constraining the planks to the formers can be removed once the core planking is complete. Then it can be faired and externally skinned. I think the front-rear fuselage can then be carefully sawn, along with the canopy frame. The rear fuselage/tailcone part can have the waistline split cut. The front fuselage can remain unsplit at the waistline. There is plenty of access to make all the internal fairing, inner skinning and structural additions. It could be that a further external longitudinal support is required, along the top centreline of the fuselage, but it would be nice if it can be done without it. There is a long way to go with this concept; especially the tail end of it. All ideas are welcome. Cheers, Justin Fuselage-Jig.zip
  12. Thanks Guys, From the plans I reckon it looks like 0.5" thick, but H35 or H45 sounds about right for the material. Eugen, I have followed your super Q1 project, and your materials link is superb. Thanks ! I will post my fuselage core idea at some time. It is basically a foam plank system, as I have used in many boats. I see no reason for the horizontal split in the forward fuselage part.... only in the tailcone part. I will figure out the tooling for this. I have no idea if I will build a Q2/200, but I am fascinated by the really logical design, that I used to think was just freaky. Well, it isn't. It has really short load paths all concentrated in a very compact design. It is utterly brilliant. Cheers, Justin
  13. Hi Folks, Can anyone tell me what foam was used in Q2/200 kits for the fuselage ? Which thermoplastic, and what density ? I have figured out a way for the homebuilder to make new fuselage cores. I guess the original cores are no longer available.
  14. Hi Folks Here is basic model of an engine mount for a UL260. I have made a spaceframe type that takes loads nearer the edge of the firewall. Some small webs inside the firewall will be added. The lower ones can transfer engine loads directly to the canard. Perhaps a few gussets are required in the engine mount. The UL installed weight is slightly lower than the dry weight of the Revmaster 2300. It also produces more peak power, and equals the Revmaster 2300 peak power at just 2800 rpm. It is about double the price of the R2300. It does offer fuel injection and FADEC. There is still a huge saving in using the Revmaster. EngineMount-Q2-UL260i.zip
  15. Hello, Well, there was little response to my ground attitude question. However, I had modeled the Q2 with standard gear and the canard jigging templates produced an anhedral of 6 degrees. This put the ground attitude at 11 degrees pitch. Somewhere I read it should be between 7.5 and 8 degrees, but almost all photos show that the pilot has a better view on the ground than the standard design really makes. Also, many photos show that people have considerably lowered the tailwheel. In the attached CAD STP file I have reduced the canard anhedral to 5 degrees. I have not lowered the tailwheel yet, but it should lower by 3.5 inches. Using a UL260i engine with a 48 inch diameter propeller, and allowing for 2" of strain in the canard and a loaded tyre radius, these changes still give propeller to ground clearance of 16.6" and a ground pitch angle of 8 degrees. Cheers, Justin STEP-Q2-Assy2023-03-11.zip
×
×
  • Create New...

Important Information