DR-1 (Sands): Builders Group - Page 237

CORVUS · 30 September 2008, 07:47 AM

Quote:

Originally Posted by Jeff Brooks

The DR1 & DVII bungee cord tubes did not run all the way through the LG wing, and although the Sands method does seem stronger, it adds weight! Aircraft are a careful balance of strength vs. weight.
The practice of over building a plane to "make it stronger" has a diminishing returns on your investment. Making the landing gear stronger by beefing it up, adds to the gross weight, and makes for harder landings!

Ron might have been concerned with splaying out forces imposed on the struts. In order to compensate he tied the struts together with those bungee tubes. When you hit the ground the wheels and struts want to splay outward and the only thing preventing that is the Axle tube and the rivets that hold the aluminum box to the steel box.

Another question I've seen brought up is the repair or replacement of those wing ribs. If the aluminum box is riveted to the steel box how do mount new wing ribs to a damaged sub wing. You can't slide new ribs on. Are the ribs in two pieces. Seems like a lot of work involved to fix one of those things. How would you minimize the time and work involved ? Make the aluminum box removable ? If there was continuous wood mounted to the top and bottom of the aluminum box, which is conjecture, how could you slide a rib into place. Was there a cutout in the bottom chord of the wing rib and they slipped over the top of the box. Wood on the bottom of the aluminum box being flush with the bottom rib cap strip. Sheathing wrapped over the front and nailed top and bottom to the wood strip. Might be able to sheath it with three pieces of 3 ply. One on the front two on the back. No need to remove the aluminum box. Sheathing tied it all together.

Jeff: Very nice looking job on that Aluminum tube. Looks like your going to build your gear like it was originally. So your saying the aluminum tube was there to give the ribs rigidity. So maybe there were no stringers. Just the two tubes that were slid into the rib holes.

Lou

Jeff Brooks · 30 September 2008, 08:24 AM

I know that one method of construction on the DVII was a split axle wing. This makes changing the shock cords easier ... and possible repairs much simpler too! I don't think that any Dr1s were done this way.
I have had to patch a puncture in the skin on the bottom of my axle wing (between the ribs) when I rolled over a piece of wood in the garage. Breaking a rib underneath the skin is a major event, in which case, I would want to tear the whole thing apart to check the stress anyway.

Many folks choose to build their landing gear under the plane during construction & then forget about the landing gear after the assembly is done. I chose to make mine using a jig so if I need to replace the one currently on there, I can do it without the plane. all the attaching points should end up the same this way. I passed this onto Maxim08 as he builds his too. I loaned him my jigs to him because it might make life easier if we needed to share parts later.

As far as stringers go ... I had several conversations via email with Achim. Take a look at his landing gear on the FTS thread. There is a neat paddle looking part that runs along the bottom of the aluminum box posted on his thread. I did not have this info when I did mine, but my next set of gear will have it. His method keeps the weight down and provides a nice monocock construction that is very strong. there is a cutout on the paddle that allows the spindles room so they don't bottom out when there is no pressure on the wheels.

CORVUS · 30 September 2008, 10:14 AM

I went to Achims thread. Very interesting to say the least. His photo's confirmed my assumptions. Very nice details. I'm still curious to know why the spacing of the original ribs of the D-VIII were not consistant.

Lou

Makhpiyaluta · 1 October 2008, 02:17 AM

Quote:

Originally Posted by Jeff Brooks

The DR1 & DVII bungee cord tubes did not run all the way through the LG wing, and although the Sands method does seem stronger, it adds weight!

They do on the original D VII in the Militaire Luchtvaart Museum at Kamp Zeist. This one has no aluminium box at all!! I don't know if this landingear was ever changed during it's life but when I saw it there was no alu box only tubes. I will try to find the photos I made and see if I can have them scanned.

Willem

Makhpiyaluta · 1 October 2008, 07:58 AM

Here's the photo.

Willem

Jeff Brooks · 1 October 2008, 08:04 AM

THAT IS INTERESTING ... how did they attach the axle wing?!?

CORVUS · 1 October 2008, 08:30 AM

Willem,

Those are great photo's ! Thanks for posting them. There's no built in steel box. Looks like a completely revised gear assembly. Maybe they did away with the gear wing altogether. Might be post war. Interesting reinforcement tieing the two gear legs together so substantially.

Lou

Makhpiyaluta · 1 October 2008, 09:27 AM

On the photo you only see the front but ofcourse it was the same on the rear side. The axlewing is a two piece one and is held only by cutouts that fit along these tubes. The plane is not a postwar but OAW 7745/18 as far as I can recal. This proves again that there was no 100% sure build D VII. These planes were adapted constantly and as we all know Fokker builds or Albatros or OAW they were all different. After the war Fokker build more D VII's in Holland and they were also different then the ones build in the war. There's just a new book release here in Holland concerning D VII's that flew for the Dutch Militairy and Navy and also for the KNIL wich were our forces in the Dutch East Indies. All were different and many types of engines, radiators and props were used.
The book is in Dutch but very interesting. "The Fokker D VII in dienst van de Nederlandse Militaire Luchvaart" written by Nico Geldhof ISBN 9789080498136

http://www.geromybv.nl/epages/615752...Shops/61575298
Use the searchbox and fill in the title to find it.

Can you guys remember the discusion about the fuel tank that supposed to be made from steel and not brass? It was said that the Paris D VII was the best reference? Wel Dick Funcke made his drawings from this one and he made photos of the fuel tank wich I posted and guess what? It was made from brass. The guy who made the statement (and thinks he knows all about D VII's) never reacted on that.
These planes were build to fly and every thing was done to keep them flying even if it was never put on drawings.

Willem

CORVUS · 1 October 2008, 01:34 PM

I'd love to see how they put those two halves onto those tubes. Apparently there was a front and a rear section. Ribs were slotted. Probably not much. Wouldn't have to go far to reach the center point. Prefabricated wing sections. I guess that's what Jeff was referring to. Sounds like a good idea. Anyone know where there are more photo's that show the inside of the D-7 gear wing ?? Stop hording your photo's. Don't you know it's better to give than to receive.