Gwfm d vii

[Der Grüne Flieger]

Yes, that is the one. The last time I saw the ORA DVII it had a picture of the Seven Swabians on it. http://www.britishflatfigures.org.uk.../Neu%20081.jpg

Phil

[Dan_San_Abbott]

John:
If I may offer some information on "RK". This Fok.D.VII, marked RK was flown by Ltn. Richard Kraut in Jasta 66, not Jasta 63. Ltn. Kraut transferred from Jasta 4 to Jasta 66 on 25 October 1918. He was assigned to Jasta 4 on 3 August 1918 coming from Jastaschule Nr.1 He achieved one victory at Jasta 4 on 26 September 1918, shooting down D.H.9 at 1715 hr south of Metz.
The turtle-deck and upper side of the tailplane were light blue and the tailplane was edged in dark blue band 75mm wide.
Happy new year,
Dan-San

[Jeff Brooks]

That other plane looks like the Rhinebeck DVII before it's paint upgrade.
Some of those flying characteristics you see are not just it being tailheavy. Since these planes did not have differental ailerons, they turn a little funny, easy to confuse with the tail end dragging it around.

[Maxim08]

Dan,
Thank you for the input. The detail that we have is limited to a few photos. Would you be prepared to create one of your colour and marking guides for this aircraft?
Regards,
John

[Flysafe]

The flying characteristics of the GWFM and other DVII's with respect to flying tail low are driven by several factors that are all linked. Aircraft total weight, tail weight, C of G, horsepower and prop RPM and pitch/diameter.

It is very difficult to make comparisons from one DVII to another without looking at the entire package.

Having flown the GWFM DVII for many years with different props, but the same engine I can say that the prop makes a huge difference. I can also say that it can be very difficult to determine exactly what horsepower your engine is putting out. Having seen our engine get "tired" I know that there are huge variances in power output.

I need to sit down and do the HP/Torque/RPM calculations for the original vs. a 200 HP ranger too to understand the relative values.

My experience tells me that on the DVII we have all three things conspiring against us to yield a tail low cruise flight - tail heavy, overall heavy, and lower thrust. this yields a lower than ideal cruise speed for the airfoil/weight combination and the resulting tail low cruise flight.

Overall the DVII is a superb aircraft to fly. Nicely harmonized controls and great low speed characteristics. It is a challenging aircraft to land due to its large slab sided fuselage weathercocking in a crosswind, poor forward visibility and tendency to porpoise on touchdown if not landed precisely. My instinct tells me that the 200 HP is slightly to low for the GWFM DVII. I would really like to fly a lighter DVII with the ranger and a DVII with the Gypsy engine for comparison.

[Maxim08]

Flysafe has been searching for alternately engined D VIIs to fly for comparison for quite sometime. He must be one of the highest time D VII people around. Anyone willing to offer up their ride for educational purposes?
Regards,
John

[Jeff Brooks]

Absolutely! I would love to have someone who has experience in the DVII fly my plane, and tell me how mine compares!
Of course, we may have to wait another year or so till the wings are done!

[Maxim08]

While work is progressing with the fuselage, I've started assembling the spar table to build a new lower wing for the museum.
The table is a modification of the 'Sands' spar table. Parts of this table have been used to build a set of Camel spars, Nieuport 28 spars, triplane spars and, hopefully soon, D VII spars.

The table is a simple concept. A series of 'A' frame legs, truncated at the top to provide a level surface for a flat table. The table top has side rails that allow you to clamp material vertically and horizontaly at the same time. Like most things you build the time and effort that you take up front will make things easier down the road.

Here's a general shot of the table sub structure. The 'A' frames are built seperately and then tied together in three ways: siderails at the top; diagonal braces A frame to A frame and a mid-height tie piece. Not unlike tieing roof trusses together.



The legs are anchored to the floor with angle brackets lag bolted to expansion anchors in the concrete. A nice level concrete pad is a benefit at this stage.


I tied the table together as a freestanding unit to allow for locating the anchors. Drilled pilot holes and then shifted the table. The holes were final drilled and the expansion plugs inserted. The table was then moved back into position.

Levelling the base was done in several ways. Each A frame was levelled along its length (the width of the table).



The table siderails were then levelled.


The centreline of each A frame had been previously marked and a length of waxed cord was stretched the length (28 feet) of the table.


The height of the cord was measured at every station. Hard to see, but the 2" square was marked at the desired string height.


Levelling was done with good quality wood shims. The highest spot at any phase of the levelling was the benchmark and other pieces raised to match. If one of the two legs in an A frame was low, it got shimmed. The highest A frame(s) were bolted down and others shimmed to match. When everything looked complete, it was rechecked in all axis. I was fortunate to have a good contractor poor a level pad. The A frames were all the same size to less than 1mm in height. In total I only used 7 shims for the table.

Next post will be about the table top.

Regards,
John

[Maxim08]

It's been awhile so a series of things on the go.

Continuing the saga of new controls for the cockpit, after ascertaining that the new stick and aileron controls will function properly, we are finishing the detail work. Today Al and I made the stiffening cones for the control column.

We first attempted hand forming some sheet but that didn't go well so the next step was to machine a cone shaped form from steel to use to form the steel sheet around. This gives us a good shape and repeatability of parts, if required. Next step is to make a flat card pattern from the form by wrapping some stiff card around and cutting to shape:



The template shape is traced onto flat stock and cut out with a bandsaw:



To make it easier to form, some preliminary shape is rolled in with a slip roller.



The sheet was tackwelded to the form down one long side. This provides a good anchor for the next steps.



The little jig holding the form was made from 2 discarded industrial casters. Each end of the cone was tapped and 2 bolts secure the form in place.

to be continued...

[Maxim08]

This is where the fun starts, acetylene torch, pliers and a hammer.



What we are doing is heating the steel to become pliable and pulling it around the form. When done, we end up with this:



Letting it cool a bit first (painful lesson) the tack welds were ground off and the cone seam welded. At this point, while it is cone shaped it's not the perfect cone shape that we would like or the airplane deserves. Our quick fix is to put the welded cone over the form, place it in a hydraulic press and lightly preload the top of the cone. Because the cone isn't round it will sit high on the form. Apply some heat, tap it a bit and you end up with a nice cone shape.



The top and bottom of the cone are trimmed to fit on the column properly. For the bottom I mark first and then use a grinding wheel. Take a bit off and fit in place, take off some more etc. Eventually, when everything fits, it is welded into place.



On the stick in the foreground a notch has been milled and the cross tube to which the elevator cables attach, has been welded in. On the right you can see the lower cone sitting in place. Note that we have a stiffener inside the lower cone. This isn't on our building drawings and may not be necessary but it was requested by several of the pilots and so has been added.

Regards,
John