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Old Jul 09, 2009, 09:52 PM
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First Ever Vintage U.S. Gull Wing Kit

I am not aware of any vintage scale U.S. gull wing glider that has ever been produced in plan or kit. If you know of any I'd be interested to learn about them.

To that end, I've begun adapting my three view to a third scale version of Jack Laister's 1938 Lawrence Tech IV gull wing glider. Its a shame that Jack passed away before I could get a set of plans from him, but I think I can still do his beautiful high performance sailplane justice and we will still donate a portion from every sale to Lawrence Technological Institute in his honor.

Mike and I have decided to conduct the beta build concurrent with the plan development so as I complete each portion, like the horizontal tail shown here, I will send the files out for cutting and email mike the PDF to plot and build over. In this way we can bring the model to market more rapidly. When final plans are complete it will only be a short time to finish covering and test flying the prototype. Our goal is to have it done in time for Christmas order in early October of this year.

If anyone is interested in building this from plans or kit, please email me at nut55@aerosente.com each time I finish and post another assembly here, and I will email the full resolution Acrobat file of the drawing. This will allow you to follow allong better with Mike's beta build and be able to give him a hand.

I appreciate your comments and questions on the design and construction and I will try to address them all here.

Tom
http://www.aerosente.com
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Old Jul 10, 2009, 08:58 AM
No substitute for aspect ratio
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Norwalk, CT aka the Nutmeg State -- I just can't seem to find any %$#@! nutmeg here?
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Fantastic, Tom. JUST what I was hoping for!! You can count me in for a kit when they're ready.
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Old Jul 10, 2009, 02:52 PM
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Tom:

Great Idea. I would like to get a kit when you have them ready.

I have lots of scale docs from IVSM for the Schweizer ships

Any word on the short kit of the 1/3 scale kit you promised?

cheers
Jim

Quote:
Originally Posted by mmartin55
I am not aware of any vintage scale U.S. gull wing glider that has ever been produced in plan or kit. If you know of any I'd be interested to learn about them.

To that end, I've begun adapting my three view to a third scale version of Jack Laister's 1938 Lawrence Tech IV gull wing glider. Its a shame that Jack passed away before I could get a set of plans from him, but I think I can still do his beautiful high performance sailplane justice and we will still donate a portion from every sale to Lawrence Technological Institute in his honor.

Mike and I have decided to conduct the beta build concurrent with the plan development so as I complete each portion, like the horizontal tail shown here, I will send the files out for cutting and email mike the PDF to plot and build over. In this way we can bring the model to market more rapidly. When final plans are complete it will only be a short time to finish covering and test flying the prototype. Our goal is to have it done in time for Christmas order in early October of this year.

If anyone is interested in building this from plans or kit, please email me at nut55@aerosente.com each time I finish and post another assembly here, and I will email the full resolution Acrobat file of the drawing. This will allow you to follow allong better with Mike's beta build and be able to give him a hand.

I appreciate your comments and questions on the design and construction and I will try to address them all here.

Tom
http://www.aerosente.com
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Old Jul 12, 2009, 12:09 PM
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I read that you are considering several options re the curved wing build.

I'm considering the same issues while designing the Blaue Maus.

It has "3" three spars with lightening holes.
That implies "4" four rib "Parts" per rib section.
Fortunately there are only 15 ribs per side plus half ribs.
This would certainly make the build a bit more "messy" but leaves the spars
intact for the whole span.

I figure to cnc cut the spar webs then glue on the spar stringers at top and
bottom. Then set them UP on the profile jig - possibly held tight with rubber bands and then attach all the rib parts.

It's essentially a MDF base with holes drilled thru along the line of each spar.
THEN a 1/8" ply cut to the "under side" shape of each spar and placed
perpendicular to the base - held on place by dowels glued to the lower edge and
inserted in the MDF base holes.

A lot of work BUT the whole thing can be flipped and used to build the other half.
Pix are now at this link ...

http://www.rcgroups.com/forums/showp...7&postcount=30

Brown MDF Base
Black dowels glued to bottom edge of profiles
profiles marked F-Font, M- mid, R- rear
Rib outline-only shown.
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Old Jul 12, 2009, 10:33 PM
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Quote:
Originally Posted by birdofplay
It has "3" three spars with lightening holes.
That implies "4" four rib "Parts" per rib section.
Fortunately there are only 15 ribs per side plus half ribs.
This would certainly make the build a bit more "messy" but leaves the spars
intact for the whole span.
Ouch! We will have only one, built as you describe with only forward and aft ribs sections. No jig will be required as they can be built "D" section first by clamping the already assembled curved and tapered spar to the bench flat. The notched leading edge will align the ribs as will the trailing edge when the aft sections of each rib are cemented in place.

Tom
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Old Jul 12, 2009, 10:39 PM
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Interesting ...

So, your model has straight / flat sections that create the gull ?
As opposed to a smooth curved underside.

The Maus has a smooth curved under side.
So I'm stuck making the wing jig.

I'll look up some info on the LT IV to see the differences.

... later ...

Oh I see that now ! :-)

I like the looks.
"Kinda" like a Reiher.

I'll be watching things develop

thanks

Bob
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Old Jul 12, 2009, 10:54 PM
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Killingworth CT
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Hi Tom, I will also be waiting for the kit. Put me down for one too.

LEN
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Old Jul 13, 2009, 10:25 AM
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Thanks for your interest and feedback! Len I will need an email to nut55@aerosente dot com to get you on the list and send you the PDFs as they become available for preview and comment.

Bob, the spar is fabricated from four parts - forward and aft curved shears plus upper and lower caps - then the ribs are jigged into the slots on the forward / aft surfaces of the spars using tabs for location and notched leading and trailing edges for alignment. This system has been used in the past successfully and you can see an example of it in use here: http://www.rcgroups.com/forums/showthread.php?t=444704.

Tom
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Old Jul 13, 2009, 11:20 AM
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Thanx , Tom. e-mail sent
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Old Jul 23, 2009, 09:21 PM
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Update Drawings Lawrence Tech IV

I've udpated the drawings with parts and will be emailing the PDFs for plan one, horizontal stabilizer. About two weeks I will have the vertical fin and rudder done and in the meantime, begin working on prototyping the parts for me to assemble.

Anyone else who is interested in building this sailplane is welcome to email me to be put on the list.

Tom
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Old Aug 02, 2009, 05:53 PM
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Lawrence Tech Yankee Doodle Vertical Tail Plane

I've completed the vertical fin and rudder and sent out PDF files to subscribers. Also attached are JPEGs of both the horizontal and vertical empenage assemblies.

Tom
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Old Aug 02, 2009, 06:07 PM
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File correction?

Tom,
It appears that the ribs on both the tail surfaces are cut out to go over the trailing edges, yet the trailing edges are also shown cut out. I believe the TE are supposed to be one piece and will slip into the rib cutouts?

Scott
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Old Aug 02, 2009, 08:06 PM
Vintage wood is the best!
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Quote:
Originally Posted by shinck
Tom,
It appears that the ribs on both the tail surfaces are cut out to go over the trailing edges, yet the trailing edges are also shown cut out. I believe the TE are supposed to be one piece and will slip into the rib cutouts?

Scott

The drawing shows R2 and E2 as the trailing edge of the surfaces as being cut from 1/8" plywood....then behind that is shown the 3/32" balsa filler panels to complete the trailing edge. The 1/8" ply trailing edge does indeed "slip" into the cutouts in the ribs and then the 3/32" balsa fillers are added to each side of the 1/8" plywood and sanded to shape to complete the trailing edge.
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Old Aug 02, 2009, 09:12 PM
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Scott,

SZD16 is absolutely correct. I will probably pare the depth of them down in the final plan and cutting files to incorporate only the final 3/8" strip around the edges of the surfaces and not the gusseted areas. Similar parts will be cut to fair the leading edges in the same way to help create good airflow by preventing the covering from sagging between the rib ends. In the end, the effect under translucent covering will look very much like full scale when back-lit.

The trick here is to make sure that all can be assembled without interference in slotting one to the other and so I left the diagonal ribs to butt join the spars where they are trapped as in the case of R6 and R8. Where they need to lock in the case of R3 and R4 they will lock into a large slot in the spar. In the elevators, diagonal ribs that bisect a parallel rib are made in two pieces.

If I do it correctly, the only fitment needed will be to bevel the ends of the diagonal ribs to the correct angles and to saw out small triangles to increase the size of the reliefs where the 1/32" (.75mm) spar channel members are let in to areas where the ribs exit the channel at other than right angles on R3, 4, 6 and 8 for example.

All the ribs are relieved to accept the channel sides but not shown here except in the cross-sectional views at the top of the sheets.

Starting on the fuselage tonight,

Tom
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Old Aug 02, 2009, 11:17 PM
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Dang,
Next time I will download the file and see if I can read the itty-bitty writing on the plans. Can I blame it on being a .jpeg file? Maybe my reading glasses weren't clean?

Thanks for the enlightenment SZD16 and Tom. I'll go back and lurk some more now
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