Guillows sheetwood flying models - the Zip nocals.

[simpleflyer]

Next, the main fuselage formers are glued in place.


Normally, in constructing the Guillows shelf model the kit procedure would be to attach the other fuselage side and nose formers and then the fuselage top sheet. This would then finish the fuselage frame and it would be sanded to shape. This now leaves the fuselage with a flat bottom that needs to covered with a paper panel cut from the plan. When we built these as a kid we built them per the plan, but the flat bottom fuselage seemed to me that it could be improved upon.

So now as we build the shelf models we add some more wood to the lower fuselage. First the formers are notched and strips added.


A 3/32 panel is glued to the under forward fuselage and 1/16 tail panel w/strips is formed.


The tail panel is glued in place.


Finally the top panel is glued in place and now we have a fully enclosed fuselage box which can be carved and sanded into the cylindrical form of the B-29.

[simpleflyer]

A couple more mods are made to the structure. In the picture below, at the top are the three die cut pieces provided in the kit for a nacelle, below is the modified structure-the nacelle top has been lengthened and a piece has been added between the top and bottom. This makes for simpler construction and adds more dept to the nacelle to bring it more into scale. As seen in the B-29 picture posted earlier, the actual nacelles have more of an oval cross section than a circle.



Another mod was the gluing of a couple basswood pegs into the bottom of the vertical tail. This allows for more strength in that area and for a removable tail.



The remaining challenge is to get a sharp knife and some sandpaper and to find a B-29 in this assemblage of parts

[simpleflyer]

Aha, the B-29 is beginning to emerge.

[simpleflyer]

Yesterday, most of the shaping of the B-29 was completed.



This simple tool (a length of pointed steel wire embedded in the end of a dowel for a handle) made the forming of the nacelles an easier task.



At this point, we were anxious for a test flight.



With a few pins for a temporary nose weight the little B-29 was able to fly.

[simpleflyer]

Today, with a couple of improvements and better weather, flight was a bit improved.





But, sudden gusts of wind are a bit of a challenge for the little craft of slightly less than ten inches wingspan.

[simpleflyer]

Today is already December 1, hard to realize that it's almost six months since our last post on this thread. One of our current Zip swinger builds is another profile version the P-40. This will be the fourth P-40 in the past several years. The last on on this thread was a mini swinger of a Guillows shelf model back in Jun 2013.
http://balsamodels.com/phpBB/viewtopic.php?f=2&t=1646&start=180
The one before that was a profile P-40 swinger based on the Guillows rubber powered DC series posted in Oct 2011.
http://balsamodels.com/phpBB/viewtopic.php?f=2&t=1646&start=45

This profile is based on an old Comet stick and tissue rubber powered model of the P-40. I had built one of these in my early teens as had one of my classmates. He had converted his P-40 to a tricycle landing gear and flew it swing control. Gee, it made neat landings.

We took the following plans.


These were traced onto a sheet of paper, where the building details were worked out.


These shapes were scanned and printed to card stock and cut out for patterns. The patterns were used for cutting out parts and building the flying surfaces.


Fuselage parts are cut out using the pattern. Tail sticks are attached to the fuselage and glued to tissue laid over the vertical tail plan.


The forward fuselage is built in layers to add strength and weight to bring the CG into its correct location. Horizontal tail and wing halves are glued up. More than 90% of the wood structure is 1/32 sheet balsa. Tail and wing wood is stripped from 1/32 sheet.

[simpleflyer]

The tail surfaces on the ZIP no-cal P-40 are built in the same method as those on the SS-30. The stick structure is built and adhered to tissue covering the building plan. When the parts are removed from the building board, they are ready for trimming off the excess tissue and shaping the tips.



Next, the doublers will be glued to the fuselage.

[simpleflyer]

Back to work on the ZIP nocal of the P-40. Wing center joint is completed. Doublers are in place and horizontal in place.



Wing ready for tissue cover.



Tissue applied and painted with thinned white glue.

[simpleflyer]

One cold dreary overcast day a few days ago we were able to make a couple of test flights with the ZIP no-cal P-40.









The weather was a bit gusty and on one of the flights the P-40 struck the tool shed causing some minor damage. A split in the fuselage near the tail.

[simpleflyer]

The weather has become much better so we took the P-40 out for some more flights.

[simpleflyer]

Whew, we've taken a few months break from this thread and it has slipped back a few pages, so we''ll bring bring the ZIP swingers up to date.

When last flying the #2 profile P-40 swinger, it seemed to have a lot of up-n-down oscillation in flight. Looked as if it needed more weight in the nose. So we added some.

SC_07-16-15_P-40-fSm.JPG

So we took it out for a few test flights and it went much better.

SC_07-16-15_P-40-cSm.JPG

SC_07-16-15_P-40-dSm.JPG

[David Lewis]

The B-29 reminds me of another way to make display models fly. If the CG is properly located, plastic scale models will glide just fine underwater. To double flight time, a towhook can be mounted on the belly. When you slip a weight onto the hook (for example, a hex nut), when the model rolls out landing, the weight gets scraped off the hook and the model climbs back to the surface. The underwater gliders that I carved out of balsa, I brushed on 2 coats of clear dope and that seemed to waterproof them.

Reynolds number for a model flying at 8 mph with 4.2 inch wing chord
= 27,000 in air
= 384,000 in water

[simpleflyer]

Seems, I vaguely remember reading about a person flying plastic models in his bathtub and possibly other locations. I think it was in the Amateur Scientist series of articles in Scientific American magazine many years ago. It makes sense, as air and water are both fluids and share many similar dynamics.

On the day when the P-40 was flown, we also flew our profile model of the XQM-93A. It is a scratch built model in the format of the Guillows DC-series of profiles(now re-issued as the #4500 series. More about the original Gu DC series is at:
http://balsamodels.com/phpBB/viewtopic.php?f=2&t=1646&start=30
Last three posts on that page.

A couple pix of the flights.

SC_07-16-15_LTV450_gSm.JPG

SC_07-16-15_LTV450_hSm.JPG

[simpleflyer]

In the late 1960's, E-Systems department of Ling-Temco-Vought was contracted to develop a drone aircraft capable of loitering over a location for extended periods of time as a communications relay. E-Systems came up with this prototype, the L-450F, a Schweizer SGS 2-32 powered by a P&W PT6A-29.

LTV_450_sm.JPG

After initial flight tests. The manned controls were replaced with a remote-controlled system.

L-450_XQM-93A_sm.JPG

The XQM-93A in flight. Although, it could fly at an altitude of 45,000 feet and had a flight endurance of 24 - 30 hours it was not selected for production.

XQM-93A.jpg

One of the manned prototypes, 72-1287 is now on display in the Frontiers of Flight Museum at Dallas Love Field.

[simpleflyer]

To build the model, first a 3 view drawing is needed. This one was found in an old magazine.

LTV_450_3vu_Sm.JPG

The 3 view is scanned and the image is edited in MS Paint so the main shapes of the aircraft are grouped together into an image for printing like this.

LTV_450_ptrn_Sm.JPG

The image is printed to card stock or to a sheet of paper. If printed to cardstock the shapes are cut from the card and used for patterns. In this case they were printed to legal size sheet and cut and glued to card to be cut for patterns.

SC_05-08-15a.JPG