April 20, 2009 Ibuki Photos: View inside the bow showing the first two 1/16" balsa 'dams' used to hold self-leveling concrete crack filler until it sets. These will step down in height from bow and stern toward amidships, directing water to a channel that will be made along the keel leading to the bilge pump. The 'dams' have been trimmed down, having been higher with arms going out each window and ca glued against the ribs. View of the first level of concrete filler in the stern. This stuff cures to a solid rubber compound over about a week, though the upper surface is dry within a day. It isn't very dense - about the same as latex. Note that I used 2mm styrene as centerline armour aft instead of 1/16" aluminum. The reason was that I was in a hurry and the styrene was easier to shape to match the hull bottom than aluminum. I may add another 1mm of styrene on either side, giving a total thickness over 1/8". The cut-out section along the top is to allow the rudder ams and their linkages to clear the armour. The rudder stuffing tubes will be protected by two layers of heavy vinyl tubing of different sizes (one inside the other). I found that worked well in other models. Sheeting the port side. It was fiddly work cutting the small pieces of balsa that fit above the secondary bulge stringer. The bulges will be sheeted after the main hull sides. Closer view of the bow during sheeting. I always sheet right up to the ends of the hull over the solid bow and stern areas, then sand the balsa, feathering it into the hull, before silk-spanning over it. It looks better than stopping the balsa short of bow and stern. I'll add more balsa below that used to sheet the windows, taking it down onto the bottom of the hull so the lower edge isn't as easy to see. Bob
Except for the last 10" aft , the hull will be sheeted by the weekend. The bow turned out very nicely, with the balsa smoothly feathered into the extreme end. The stern can't be sheeted until I decide whether or not to shorten the hangar and lengthen the quarterdeck. The hangar length matches the end bulkhead locations shown on the Ibuki cross-section plan and the bow and stern frame drawings in 'Japanese Cruisers of WWII', but those drawings seem wrong based on the one side view photo of the stern found. I think the hangar's at least 3/4" too long but to shorten it and reglass the rear of the hangar would delay construction several days and I'm already a few weeks behind schedule. That's something I could do next winter. The quarterdeck will be complicated to make with wing-like overhangs to port and starboard, 4 support pillars for the flight deck and the need for an access hatch to the rudders. The forward pair of pillars sits exactly over the rudder stuffing tubes so the entire aft section of the flight deck has to be removable to get at the rudders. Bob
Bob I have found a couple of things that I did wrong on my Hood, but plans to go ahead with the build, so that I can get her on the water. I will re-work the mistakes later this year, or over the next winter. Mikey
I was just looking for more photos Bob and I came across this, maybe another subject for later? http://www.steelnavy.com/images/NavyPlan/NPMogami7587P&Psheet.JPG Front half typical Mogami with guns, back half all carrier deck with Seaplanes, a for-runner of some modern designs to be sure.
Hi Bryan, The link didn't work but I know what you're talking about. John Coffill built an IRCWCC Mogami with the aft flight deck and 2 BB cannons underneath it. It was sold a few years ago to someone who never used it and rejoined the NATCF/NABS fleet at the Shearwater Museum show in April. I think it's under refit to Treaty stats. It'll be nice to see it and the Ibuki running together. Bob
here let me try it this way p> It would allow you to build a carrier and still put teeth in its front end, 3 guns forward and a half unit pump sounds like fun....
The last time I worked on the Ibuki was more than 4 years ago. After the I-400 submarine mould project was finished and several hulls made and sold (2009-2010) cottage renovations and construction of a guest bunkhouse and a workshop took up my spare time for 3 summers. It's only in the past month that I've got back into RC naval combat, in part because my wife keeps complaining about all of the models and hulls taking up storage space in the basement! Ibuki was back on the workbench last night. I did a websearch and found more photos, one from above in drydock that shows the elevators are not far off from the positions shown in several different drawings. A side view photo of the anchored hulk showed the actual elevators sticking up in positions that did not match any plans, but the overhead view shows the elevators were not in their shafts but sitting away from them on the flight deck. The plans all show different lengths of deck ahead and aft of the hangar, and there aren't any good photos of the those features. I'm pretty sure the quarterdeck should be up to 1" longer but probably won't cut off the rear wall of the wall and glass on a new one further forward. At this point hull sheeting has to be completeed and then the external details will be done (catwalks, bridge and gun platforms). I may not arm the model for Treaty or IRCWCC combat if it's allowed to be used as a convoy ship. However, Ibuki was only 80% complete when scapped and was never used as a transport. At the 2003 IRCWCC Nats there were a few Japanese CVL's being used as convoy ships in the Campaign event, so if anyone can clarify whether Ibuki can be a convoy ship please let me know. If it can't be a convoy ship I'll arm it for fun.
After looking at drawings and photos again I've decided to shorten the aft end of the hangar by 3/4". The quarterdeck is definitely too short. You can see part of what has to be cut off in the second photo of the post at the top of this page. I can save the back wall of the hangar and re-glass it to the hangar sides further forward. The breeches of the BB cannons will protrude through the aft wall of the hangar just above deck level. Conveniently the quarterdeck slopes downward toward the stern. The next step will be to install the quarterdeck with an access hatch to the twin rudders and 4 large columns to support the overhanging flight deck. Photos will be taken but after 4 years I've forgotten how to post them. Motors are on hand and motor mounts and u-joints will be ordered this week. As usual in my smaller models the motor mounts will go on an aluminum plate, which will be flipped over with motors hanging underneath and the plate supported by a tripod of brass bolts glassed to the hull bottom. Nuts on the three bolts under the plate will allow fine tuning of motor alignment to the prop shafts.
This morning Ibuki's fiberglass hangar was shortened by 3/4" at the rear, using a razor saw. With some dremel work the end wall can reused and glassed into the resulting opening. With the end wall off I can drill holes in it for the two BB cannons it's allowed under Treaty rules. (I forgot to do that before installing the hangar on the hull.) I hope to install the quarterdeck and aft section of the flight deck this long weekend (Thanksgiving in Canada). I've considered shortening the forward end of the hangar to match all drawings of the ship, but the hangar plan showed it extending further forward than the drawings and it looks correct compared to the few available photos. That said, the hangar plan was clearly wrong aft. Though the hangar width at deck level matched the hull width aft when installed on the hull, the quarterdeck aft of the hangar was clearly clearly too short compared to photos. Shortening the hangar at the bow end would mean rebuilding the girders that support the forward flight deck, and the detailed front wall of the hangar with watertight doors, ladders and gangway, which I'm reluctant to do. I think the hangar plan I was given may have reflected an initial design that was shortened aft, if not forward, to reduce topweight. A trip to local hobby shops just now revealed that not only are they unable to obtain silkspan, they've also stopped carrying SIG dope and thinner and don't intend to stock either again! That means that even if use my wife's tissue wrapping paper I can't finish the hull, having only half a bottle of dope and half a can of thinner left. Even the major on-line hobby store in nearby Prince Edward Island doesn't carry dope or thinner any more.
Clear lacquer will work, so will a mixture of contact cement thinned with MEK at a ration of 1:1. Mike Mangus found a silkspan replacement that passes the drop test and leaves nice clean holes http://www.easybuiltmodels.com/parts.htm#silkspan About the 11th item on the page
Nearly two years after the last construction post IJN Ibuki has been dusted off and the cut-off hangar rear wall found. Ralph dropped off some excess gelcoat and resin for me today to make an Indefatigable hull, so I'll be able to glass Ibuki's rear hangar wall back onto the shortened hangar in a few days. This time I'll remember to drill the holes for the BB cannons first! I also have to make the fiberglass quarterdeck. After the hangar wall is back in place and the quarterdeck installed I can install the rear section of the flight deck and the large support beams for it on the quarterdeck. I won't be shortening the hangar at the forward end, due to uncertainty about it's actual length and conflicting drawings (and completion of the detailed forecastle area two years ago!). Because refitting the Canarias and Cumberland/Suffolk has priority at the moment I plan to finish Ibuki's stern area, sheet the stern when I re-sheet the heavy cruisers, then take a break from Ibuki until the cruisers are done. I found a nearby source for SIG dope and thinner tonight but have very little silkspan left. When work on Ibuki resumes the plan is to complete the model's exterior details before I install the rest of the internal equipment.
I'm still wondering how to build the Ibuki's quarterdeck and have easy access to the rudder linkages. There are 4 large square cross-section pillars and connecting girders that support the overhanging end of the flight deck. The aft pillars are quite close together (just enough room for the stern gun to fire between them), and there are overhanging platforms for ships boats on either side of the q-deck. I think it will be easier to make the quartedeck from 2-3mm styrene instead of fiberglass, with an outer section attached to the hull by making it a very tight fit, and caulking the underside against the inner hull. The flight deck pillars will be attached to that piece. The access hatch above the rudders could rest on styrene flanges glued to the bottom of the outer deck section, and be secured by a small bolt. The aft section of flight deck will have to lift off the pillars and the rear end of the hangar, probably using the same system as at the bow (see photos of the bow set up on page 8).
Dohh!! again. Looking at the photos on page 8 I realized I forgot to add the main bulge stringers amidships. When cutting out the hull a few years ago I was focussed on making the secondary bulge stringers, forgot to tape the main stringers and accidently cut them out with the 'windows'. I had to remake 10 of them in fiberglass but forgot I could do 2-3 more amidships where the secondary stringer is entirely within the 3/8" deck stringer. More fiberglass work to do before the weather gets too cold in 3-4 weeks!
