I am interested in making an auxiliary baggage compartment in my -9A tip up behind the main compartment and want to hear about some ideas accomplished. It will be sheeted to avoid any loose items reaching the bellcrank/pushrod. Roger Ping had a nice area between the 706 and 707 bulkheads above the longerons. I am interested in an area for light items such as sleeping bags - not sure I could squeeze bags into Roger's area. Another option would be to make a compartment between 706 and 707 but fully vertical from floor to top using one half of the bay, keeping the pushrod on the outside of the compartment. My concern here would be compromising so much of the torsional stiffening provided by the rear wall of the existing baggage compartment. Which brings up - how important is this component?
Van's Air Force
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Auxiliary baggage compartment
- Thread starter cnpeters
- Start date
DGlaeser
Well Known Member
Only Van's knows for sure...
That's a question for Van's engineers, but I would expect them to say that the baggage bulkhead is not structural. The exterior skins in this type of structure carry the load, both bending and shear. The frames are important of course, for shear as well.
The biggest issue you need to investigate is Wt & Bal. It may surprise you how little weight it takes back there to get into an aft CG condition. Run some numbers. Those 'light' sleeping bags may be heavier than you think
Even the material you add to enclose the area will have a noticeable (and permanent) effect on your CG.
That's a question for Van's engineers, but I would expect them to say that the baggage bulkhead is not structural. The exterior skins in this type of structure carry the load, both bending and shear. The frames are important of course, for shear as well.
The biggest issue you need to investigate is Wt & Bal. It may surprise you how little weight it takes back there to get into an aft CG condition. Run some numbers. Those 'light' sleeping bags may be heavier than you think
Even the material you add to enclose the area will have a noticeable (and permanent) effect on your CG.
Bruce Reynolds
Active Member
The Baggage bulkhead is structural:
The manual says not to fly the plane without it installed. Since that is the case, modify it at your own risk. Remember that "every ounce counts". A light plane performs beter than a heavy one.
Bruce Reynolds
RV-6A
The manual says not to fly the plane without it installed. Since that is the case, modify it at your own risk. Remember that "every ounce counts". A light plane performs beter than a heavy one.
Bruce Reynolds
RV-6A
Rear Baggage Modification
Carl,
I have seen several comments on the rear bulkhead being a structural part. I made a modification to mine, but reinforced it both vertically and horizontally. I believe it to be sound. There are a couple of pictures on my kitlog, but not any real good ones. Essentially, I cut a hole in the baggage compartment bulkhead and added some nutplates to the vertical member in the middle. In addition, I added a piece of .062 angle to it vertically. At the top and bottom of the cutout, I also added a peice of angle to strengthen both of those areas. I ordered a seat back as the pattern matches the rear bulkhead and hinged it from the bottom. At the top, I bought some milspec fasteners to close it up. All the framing for the floor, sides and top are 1 x 1 x .062 angles and the walls and top are .025 sheet. The bottom is .050.
I have finished painting the parts but haven't riveted them in place yet. If I can help you any way, pm me.
Carl,
I have seen several comments on the rear bulkhead being a structural part. I made a modification to mine, but reinforced it both vertically and horizontally. I believe it to be sound. There are a couple of pictures on my kitlog, but not any real good ones. Essentially, I cut a hole in the baggage compartment bulkhead and added some nutplates to the vertical member in the middle. In addition, I added a piece of .062 angle to it vertically. At the top and bottom of the cutout, I also added a peice of angle to strengthen both of those areas. I ordered a seat back as the pattern matches the rear bulkhead and hinged it from the bottom. At the top, I bought some milspec fasteners to close it up. All the framing for the floor, sides and top are 1 x 1 x .062 angles and the walls and top are .025 sheet. The bottom is .050.
I have finished painting the parts but haven't riveted them in place yet. If I can help you any way, pm me.
N941WR
Legacy Member
Carl,
If you can't fit your sleeping bags in that area, you need to get new bags. All of the six or seven bags I have will fit in there, even my zero degree bag.
When you are ready, go to Campmor and buy a good North Face poly bag. (My favorite is The North Face’s 20 degree Cat's Meow bag, which has kept me warm down to 5 above. It is very light and compact. The trick to polyester bags is to hang them up when not in use so you don’t compress the hollow fill fibers. I used to work for the manufacture of the insulation and tested a few of their bags.)
Also, depending on the type of camping you are thinking about, I'm not really sure you need to extend the baggage compartment. There is tons more room in the stock baggage compartment than two of my expedition backpacks could hold and I've lived out that pack for over a week at a time.
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osxuser
Well Known Member
Re bulkhead... structural? I think not. Most likely the reason they say not to fly without the rear bulkhead installed is to prevent stuff from falling down the tail and jamming control surfaces.
Look at the material, thickness and design of the rear bulkhead, those corrugated sheets won't handle a load.
Look at the material, thickness and design of the rear bulkhead, those corrugated sheets won't handle a load.
Mike S
Senior Curmudgeon
osxuser
Well Known Member
Congrats on post 2000...
I guess it depends on what Van's considers "structural." I'm sure it does carry some loads, it is riveted to the airframe after all. I guess what I meant was, it's not a primary load carrying structure, like the skin or spar. Don't remove it entirely, but as long as the basic framework is there, there is not any tension or compression in the bulkhead skin as far as I can tell. When you are up flying next time push on it with your finger and see how much oil-canning there is...
I guess it depends on what Van's considers "structural." I'm sure it does carry some loads, it is riveted to the airframe after all. I guess what I meant was, it's not a primary load carrying structure, like the skin or spar. Don't remove it entirely, but as long as the basic framework is there, there is not any tension or compression in the bulkhead skin as far as I can tell. When you are up flying next time push on it with your finger and see how much oil-canning there is...
Caveman
Well Known Member
uhhh Hello
Guys,
Bruce Reynolds works for Van's. He gave me my demo flight. I think I'd listen to what he is hinting at. I'm not an engineer, but I know you can over build and come up with the same end result as having a structure too weak. Unless you have a real good aero engineer look at what you plan, I'd tread easy in these waters.
My two cents... back to the garage.
Guys,
Bruce Reynolds works for Van's. He gave me my demo flight. I think I'd listen to what he is hinting at. I'm not an engineer, but I know you can over build and come up with the same end result as having a structure too weak. Unless you have a real good aero engineer look at what you plan, I'd tread easy in these waters.
My two cents... back to the garage.
I asked Van's about 2 years ago
And was told an extended baggage area was probably possible so long as the CG and control systems were uncompromised.
I would think if it were truly "structural" meaning "required to be installed unmodified exactly per plans to withstand flight loads", they would have pointed that out.
And was told an extended baggage area was probably possible so long as the CG and control systems were uncompromised.
I would think if it were truly "structural" meaning "required to be installed unmodified exactly per plans to withstand flight loads", they would have pointed that out.
Norman CYYJ
Well Known Member
My question for you is why do you need baggage area. 100lbs of baggage aft of the seats is a lot of junk. I carry to folding lawn chairs in their bags, 2 sleeping bags, tent, air mattress and pump clothing for two for two weeks, coleman cook stove and plates and pots, pillows life jackets all under 80 pounds, some tools, axe tie down pins and rope and first aid kit and still have room to pile more in on top on it.
You get more than 100 pounds back there or even further and you are going to have a plane that handles very poorly and probably out of the C of G range. It might be within the C of G with full fuel but please do the calculations for minimum fuel load. Be Safe.
You get more than 100 pounds back there or even further and you are going to have a plane that handles very poorly and probably out of the C of G range. It might be within the C of G with full fuel but please do the calculations for minimum fuel load. Be Safe.
GOLF CLUBS
My reason is golf clubs without having to dump them all out of the bag, put them in crummy day bags, stuff them under the seats, etc. I want to throw them, stand bags and all (22 lbs. each, mostly at the head end) into the back like a Cessna and pull them out at Myrtle Beach ready to go.
My reason is golf clubs without having to dump them all out of the bag, put them in crummy day bags, stuff them under the seats, etc. I want to throw them, stand bags and all (22 lbs. each, mostly at the head end) into the back like a Cessna and pull them out at Myrtle Beach ready to go.
Thanks, all, for the thoughtful replies. Norman - you alleviate my biggest concern, which is the plane's ability to hold plenty of camping equipment (my main envisioned scenario). The extra area would be for light stuff like sleeping bags, but sounds like maybe overkill. I'll run some W&B calculations and check it all out - likely will just scrap it.
L.Adamson
Well Known Member
Personally, I consider it VERY structural in torsion. I work with sheetmetal nearly every day in my HVAC business. When I add an "end cap" to a four sided duct, or box structure; it becomes very rigid, won't twist, and can support a lot of weight. It's surprising what a box structure can support, compared to the rather flimsy material it's made of. The corrugations of this bulkhead also add considerably to the strength.
This bulkhead is the "end cap" in my mind, and has all the screws needed. But then I'm not an aircraft designer, so.................?
L.Adamson --- RV6A
RV7Guy
Well Known Member
Storage
I've posted this a couple of times but I built a box behind the baggage bulk head that goes all the way to the last bulkhead. The top of baggage bulkhead is hinged and fastened with Skybolt butterfly fasteners. The bottom is stock configuration.
The box frame is made from band aluminum and angle. The bottom and sides are made from Coroplast. Coroplast is a very light and durable cardboard looking material. The entire assembly is less than 3 pounds.
I use the box to carry radio controlled sailplanes and try not to put more than 5 lbs back there. I've also used the box for jackets, pillow and sleeping bags. Very handy.
I'll see if I can get some photos up.
I've posted this a couple of times but I built a box behind the baggage bulk head that goes all the way to the last bulkhead. The top of baggage bulkhead is hinged and fastened with Skybolt butterfly fasteners. The bottom is stock configuration.
The box frame is made from band aluminum and angle. The bottom and sides are made from Coroplast. Coroplast is a very light and durable cardboard looking material. The entire assembly is less than 3 pounds.
I use the box to carry radio controlled sailplanes and try not to put more than 5 lbs back there. I've also used the box for jackets, pillow and sleeping bags. Very handy.
I'll see if I can get some photos up.
kentb
Well Known Member
I can't find my pictures.....
So I guess you will have to take my 1000 word description of what I did.
I saw another -9 builder (he works for the FSDO as an experimental specialist inspector) with this same setup.
The next bulkhead back from the baggage bulkhead has a cover made for it that extends down to the main longron. I added plate-nuts on this bulkhead and then a few on each of the main longrons. The floor is made in two pieces with one having a J stiffener along it seam with plate-nuts. I also added a J stiffener to the top of the lower baggage bulkhead with 2 plate-nuts.
So I ended up with three pieces of .016 sheet that seals off a compartment behind the baggage bulkhead. All this weighs only 2.5 lbs. I didn't change the baggage bulkhead screws for something easier to work with. If I don't what that weight back there I can leave the extra pieces at home.
I will only allow 10 lbs into this station of the airplane.
I did a static test of the structure with two 25 lb bags of lead shot.
I have yet to use this area for anything, so it may turn out to be waisted effort.
If anyone wants pictures, I could open it up and take some.
OK is wasn't quite 1000 words, but I most likely forgot something.
Kent
So I guess you will have to take my 1000 word description of what I did.
I saw another -9 builder (he works for the FSDO as an experimental specialist inspector) with this same setup.
The next bulkhead back from the baggage bulkhead has a cover made for it that extends down to the main longron. I added plate-nuts on this bulkhead and then a few on each of the main longrons. The floor is made in two pieces with one having a J stiffener along it seam with plate-nuts. I also added a J stiffener to the top of the lower baggage bulkhead with 2 plate-nuts.
So I ended up with three pieces of .016 sheet that seals off a compartment behind the baggage bulkhead. All this weighs only 2.5 lbs. I didn't change the baggage bulkhead screws for something easier to work with. If I don't what that weight back there I can leave the extra pieces at home.
I will only allow 10 lbs into this station of the airplane.
I did a static test of the structure with two 25 lb bags of lead shot.
I have yet to use this area for anything, so it may turn out to be waisted effort.
If anyone wants pictures, I could open it up and take some.
OK is wasn't quite 1000 words, but I most likely forgot something.
Kent
SteelMike
Well Known Member
Hey guys,
I read this thread with interest because I'd really like to be able to transport skiis and/or snowboards in the RV-7 I'm considering building. Anyone have any experience with this?
Skiis and snowboards amount to considerably more weight than golf clubs, I'm guessing, and I wonder what this would do to w/b. Would love your thoughts.
mike
I read this thread with interest because I'd really like to be able to transport skiis and/or snowboards in the RV-7 I'm considering building. Anyone have any experience with this?
Skiis and snowboards amount to considerably more weight than golf clubs, I'm guessing, and I wonder what this would do to w/b. Would love your thoughts.
mike
OK, I ran some weight and balance calculations using Dan's calculator ( http://www.rvproject.com/wab/wab.jsp ), and Dave Burden's RV-9A which is almost identical to what I intend (IO-360, Catto 3 blade fp, SJ cowl). I made the aux baggage station 20 more inches behind the main baggage compartment at 144 inches. With 2 X 225 lb passengers, full fuel, 100lbs of baggage, I can add more than 40 lbs back there and still be in the CG limits! Not too shabby. Now the total a/c weight will be close to 1900 lbs, but determining max weight vs using Van's numbers is another thread!
kentb
Well Known Member
Keep working on your design changes.
Carl, make sure that you build enough structure to hold 200 lbs if you want to put 40 lb back there.
Remember the plane needs to hold together when you hit bumps and pull some G's.
Kent
Carl, make sure that you build enough structure to hold 200 lbs if you want to put 40 lb back there.
Remember the plane needs to hold together when you hit bumps and pull some G's.
Kent
Naw, I would just use it for jackets, sleeping bags, pillows, etc. I don't see more than 3 lbs for structure and 10 max for any baggage.
