Gwfm d vii

[Maxim08]

Steve,
We anticipate the aircraft being ready for the 2010 season. One challenge that we regularly face is a lack of hangar space. With aircraft packed, over/under lapping wings etc, we can get 5 of the 7 in our hangar.
In a practical sense major work such as the D VII project get put aside for the airshow season which means that we have until the end of May 2009 for most of the work.

Next fall should see engine runs, inspection and the start of recovering.

My project consists of fuselage and lots of parts. Currently building the spar table so that I can get the spars done, put up and out of the way and clear my shop for assembly.

Regards,
John

[SCMc]

Hi John,

Thanks for the reply. I am looking forward to seeing the progress on both.

Steve

[Maxim08]

Some more progress today by the retired guys.

All fittings are being cleaned, sandblasted, inspected and repainted (if they pass).

'Doc' at the cabinet:



After sandblasting.



These are two of the four lower wing spar to fuselage fittings. That's part of the upper wing in the background.

Biggest repair at this time is fixing the two lower longerons from the frame behind the pilot seat to the aft section of the lower wing cut out.

Here's a before:



Apologies for the crap photo. I must get a better camera but I think that you can discerne the convoluted path of the longeron.

Cutting out and splicing in new tubes isn't a difficult task but it is time consuming. Everything that you need to know is in AC43-13B which is our touchstone for this type of work.

Before you start chopping at random you need to determine where everything should be, where it is now and how to get from one to the other. In this case it was just fitting tubes. When you splice tubes of the same OD, you need to cut them at a 30 degree angle and sleeve the inside with a tube of equal wall thickness. In this case its 0.049".

Here is the primary splice on the vertical behind the seat:



You can see the two rosettes that go through the outer tube and allow welding to the internal sleeve. The 1/8" gap allows enough room for a proper bead between the sleeve and outer tube on each side.

This is the overall layout for the repair:



While we do use vertical belt sanders, tube notchers etc, with thinwall tube a fast and precise fit can be done the traditional way.



That's all for now.
We have about 8" of fresh snow drifting to 3 feet. Time to crank up the snow blower.

Regards,
John

[Joe Perkel]

John,

What gage are these fittings? They look quite substantial!

Nice retirement project!

[Maxim08]

Joe,
I goofed on the description. Those brackets are for the strut that attaches to the rear spar on the upper wing. They are 5mm thick which is slightly more than 3/16". Jeff Brooks has some good images of the front spar brackets which he used when welding the fittings into his cabane tripod.

The lower wing attach brackets are 3mm thick.
Regards,
John

[jumpinjan]

John,
I don't understand the frame repair. If the longerons are bent, did they pull the bends out first? And why the replacement of the tubes? Is it impossible to straighten 4130 after they are bent? It looks to me like the stirrup created an upward force on the longeron when it contacted the ground, and pushed that whole side up. I think that stirrup needs to break-away somehow under impact.

Jan

[Maxim08]

Jan,
The reason for the replacement was predicated by the vertical tube behind the pilot's seat.
Whether caused by the original construction or the first repair, the vertical tube was 20mm short. This tube had to be lengthened and the longeron altered to suit. Because the longeron is now in a different ('correct') position it requires changes to both a triangluating side tube and the two transverse tubes that pick up at the two tube clusters.
Much of what we are finding is that a single change earlier in the airframes life (usually for some undefined expedient rationale) causes multiple 'fixes' to correct. Because the two verticals were made too short, we are in the middle of an estimated 20 hours of fix.
BTW, its not that the aircraft wouldn't have flown the way it was, it just wasn't 'right'.
On reviewing your post I overlooked your comment on the footstep stirrup. Original design had this attached to the fuselage with two clamp type fittings. At some time it was welded into place and therefore couldn't give and rotate. While this caused some distortion it was the short vertical tubes that initiated this work.
Regards,
John

[Maxim08]

Just realised that its been 2 weeks since my last post.
While there has been Christmas and New Year in between we keep on working...

My last few posts referred to the repairs required to modify the two lower longerons and the vertical (ok, slightly inclined) tubes behind the pilots seat. I guesstimated at the time required to be about 20 hours to complete. It actually took closer to 50.

General overview of the repaired/modified area.



Primary cluster. You can see the tubes jigged together in post #13.



The front of the fix just aft of the lower wing rear spar pickup.



The fuselage today.



Our next step will be to mount the engine. Our plan is to review the original installation and see if there are any better ways to utilise the space available to us. Some of items we are looking at include engine cooling and exhausting, plumbing, weight distribution, component location, improved servicability, more authentic appearance. etc.

Regards,
John

[Maxim08]

A bit of a breather in the hangar today involving general tidying up etc.
A few things accomplished. Rino and the paint team have sprayed epoxy primer on all of the control surfaces.
Created two small jigs for fabricating some pieces and, we weighed the fuselage!

Jeff, take note. Completed fuse with tailwheel spring but no seat or stick, 138 lbs. with your scale. I can't locate my McCook reports so I do not know how this compares. The French report used by the 1918 Flight article included the Damiler/Mercedes engine in it's fuselage weighing so doesn't help much.

An interesting and undocumented feature came up when we trial fitted a crankcase to the engine bearers. Our D VII has the engine shifted approximately 7 inches forward of where it should be. The cowling frames are lengthened as well. It has been flying in this configuration since 1977. Frankly, never having seen it in close proximity to a 'real' D VII, no one ever noticed. Not even on the set of 'The Aviator' where a couple of other D VIIs were sitting beside it.

The pilot reports indicate that this aircraft flys in a tail down attitude. Mind you, reports from the era indicate the same attitude in cruise. The question is really for other builders of Ranger powered D VIIs. Should the engine be shifted forwards?

Interested in any comments (Jeff!!)

Regards,
John

[gipsymoth236k]

Hello John,

We know that the original D.VII fuselage was constructed mostly of 1mm (0.039") wall tubing. Is this repro D.VII's fuselage made from 0.035", or 0.049" wall tube?

Thanks,
Gary Sewall
garysewal@aol.com