HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 08, 2012, 05:00 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Dummy eng - couple more points

I used Tamiya primer (great stuff) along the way to tell me how I was doing on the seams. The black plastic makes it hard to see what is going on, so lightly prime the part a couple times after ea sanding/filling. I told you this takes a long time!

I also used a brass brush to clean out and scuff the cyl fins after sanding/filing. This worked well, just don't overdo it. Cyl fins can be made slightly deeper with the razor saw. Be careful.

Don't glue any details onto primer - sand both parts first where they are to mate.

All the detail parts have ejector pin marks, protrusions, and molding seams all of which require attention. Some tubes and parts therefore may be best made from scratch. Also, pay some attention to how strong the detail will be and if it will stand up to modest vibration etc. For ex, it may be better to install the pusrod tubes with plastic mounting pins rather than the flush butt joint that the kit calls for. I may actually use alum tube for these however.....
casor is offline Find More Posts by casor
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 08, 2012, 09:23 PM
Registered User
Ny-RC-Flyboy76's Avatar
United States, NY, Cortland
Joined Mar 2009
49 Posts
Looking good Rob !! 2 things When do you think the kit will be ready ? ( already have 3 orders for you ! lol ) and where do I register for the 30s race next year ? I have 3 possible builds !


keep up the amazing work !!

Paul
Ny-RC-Flyboy76 is offline Find More Posts by Ny-RC-Flyboy76
Reply With Quote
Old Oct 08, 2012, 09:28 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Hey Paul

Quote:
Originally Posted by Ny-RC-Flyboy76 View Post
Looking good Rob !! 2 things When do you think the kit will be ready ? ( already have 3 orders for you ! lol ) and where do I register for the 30s race next year ? I have 3 possible builds !


keep up the amazing work !!

Paul
The model is going well but have not spent gobs of time on it this past wknd. I am however starting to make the tooling for the tailcone but still have to make the wheel pants, cowl and canopy. After the fuse is well onto its way being finished I will get to that. So, perhaps by the end of Oct.

I have asked Thayer to post the details of the classic "race" on the NEAT fair site and will check. I will let you know when it's up. Thanks for the comments!
Rob
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 10, 2012, 12:24 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Finishing the fuselage

I spent some time primping the wings and empennage with dope and filler after rounding out the control surfaces and LE's. What's left is the gull and the LG as far as building is concerned. The gull can only be installed after the fuselage is finished and ready for paint. To this end, I filled cracks and wood grain and gave the entire fuse a coat of thinned nitrate dope to waterproof it and to toughen up the skin. I then sanded it round but it still exhibits a rather faceted shape, like the head of a hex bolt. This is easily seen under incandescent lighting.

My sheeting job is good but, no matter how hard you try, balsa will tend to flatten out where it is unsupported. It always happens - you can sand some of this out but if you get too aggressive the skin will get too thin over the underlying structure. I want to get this thing as round as possible before I apply the fiberglass - the glass will not hide imperfections like this and will most likely get sanded through if I glassed now. The only answer is filler - which adds weight.

So, I applied a guide coat of primer to see how bad the surface is and then brushed on a mixture of vinyl spackle and water, adding a few drops of Minwax polycrylic water based flat varnish - getting it all to a heavy cream consistency. The Minwax is there to make it flow and stick better - don't use too much as it makes the filler harder to sand. The doped surface should stand up to all the moisture in the mix. Shown is the first coat and I will apply a second - it only takes about an hr to dry - and then sand it all off hoping that what remains will be in the flat areas that need to be round. The gray primer guide coat underneath will tell me if I am sanding too much.
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 10, 2012, 12:37 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Tailcone

I am planning on making a vacuformed tailcone to keep the weight down - esp all the way back there - plus being able to pop this off will give me access to the internal elev/rudd linkages and the ability to install the tail skid last.

I cut a series of concentric rings from 3/16 balsa with a 1/4" hole in the center of ea. I slid them all on a 1/4" dowel, tack gluing ea ring to the one before it, but getting no glue on the dowel. Then, I glued the largest ring securely to the dowel and chucked the mess in my lathe. I rough sanded it with the lathe spinning and then applied a series of coats of Evercoat filler using an auto body spatula - rotating the lathe head this time by hand to spread the filler. After ea application, I block sanded it with 60 with the lathe spinning but cleaned it up in situ.

Still have to finish this up, but it came out pretty good and is perfectly conical. When finished I will cut the glue joint with a pc of sharp tube, slice the cone down its center and make a vacuform plug - more later.
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 10, 2012, 02:16 PM
Brooklynite In Texas
Manor, TX. USA,
Joined Jul 2008
580 Posts
CASOR

Nice build, your doing nice work.

I have a bulldog built up from DON NEIL plans I won't be flying it. I built it for a friend that passed away. it can be seen on my blog so I won't post it here.

keep up the nice work

DONNY
donnyman is offline Find More Posts by donnyman
Reply With Quote
Old Oct 10, 2012, 02:34 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Hey Donny

Quote:
Originally Posted by donnyman View Post
CASOR

Nice build, your doing nice work.

I have a bulldog built up from DON NEIL plans I won't be flying it. I built it for a friend that passed away. it can be seen on my blog so I won't post it here.

keep up the nice work

DONNY
I have seen the plans to that model, it's very nice. Lot of work. Please do post anything you have here, I think all of us would love to see it.
Rob
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 12, 2012, 11:34 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
More Wm Bros Dummy Eng

It's as cold as Dec in SE Pa - I want to take the filler off the fuselage and was planning to do outside to keep the shop dust down but, "faggettaboutittt". Way too cold and my tolerance for it I think goes up by about 5 deg ea yr. So, I reluctantly work on the dummy eng when I can't do anything else.

It's taking me about a full hr to do a single cyl and this is after I have carefully leveled the halves as already described and stuck them together. And, still, they are not perfect. Due to the age of the molds, the ancient molding process and tooling and the shrinkage that occurs when the warm parts come out of the mold, the fins are all over the place. On the head, some are high while adjacent ones are low and sometimes you have high/low where they are supposed to join level, side to side. On the top, there are fins on one half that have no corresponding fin on the adjoining half. And of course, no matter how good you are, the "good" fins sometimes don't line up in a contiguous line - they "jag" at the seam. These issues are mostly with the cyl head - the cyl fins below the head are generally pretty good.

The procedure I settled on is to first feel around for any height differential around the cyl's circumference and take these areas down so that the fins are at least level to start. Sometimes the fins need filler (CyA) at their joint. Once they are all level, many are not deep enough due to the material removed. So then I hit these with the razor saw. Same goes for any glue blobs in the valleys. Once this is done I take autobody 220 that comes on a roll and is backed with adhesive, fold a small pc over and use this to eliminate "jags" or blobs in each of the fins the seams. The folded and stuck together 220 is very stiff and thin and is perfect for this annoying process. Any fins that need to be sharpened, I do with a pointed, oval cross section file and a flat file is use to take down seams in other areas. But I use the 220 almost exclusively.

As noted, only when you apply primer can you really see what progress you're making, so I do this about 2-3 times for ea cyl.
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 13, 2012, 06:30 AM
Brooklynite In Texas
Manor, TX. USA,
Joined Jul 2008
580 Posts
pics

Ok!

This pic wil show the size.
donnyman is offline Find More Posts by donnyman
Reply With Quote
Old Oct 13, 2012, 11:10 AM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Hey Donny

That's the nicest one I've seen. I think I remember viewing your build some time ago when I was designing my smaller model. Could you give me some details if you have the time, such as if the fuselage uses a removable frame to build. I saw the plans some time ago and just forget. Perhaps some specs would be great also.
Thanks for posting
Rob
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 13, 2012, 04:25 PM
Brooklynite In Texas
Manor, TX. USA,
Joined Jul 2008
580 Posts
CASOR

Thanks for the compliment, there is at least one more I know of on this site that has flown and looks very nice! short kits are available thru "Precision Cut Kits"
but no plans.

The construction of this is with flat sheet on which the formers set perpendicular
the the stringers are added and planking is inserted between them to get the solid forward area. the span is 97" power is a Sachs 4.2 I installed pull pull on the rudd/elev. I made pullies for this. Dual Ailerons servos locate in the fairngs on the wings.

I followed the plans almost religiuosly as the plane wasn't mine. the wing struts are functional aluminum tubes shaped with balsa. the canopy removes in a scale manner to compliment the fuse access belly pan. the L.G. fairings is shaped ALUM. as is the tail cone which is removable to access the rudder bellcrank. clicking on my avatar name will get you to my blog then look in the B dog update thread it will give you a better idea of what I said
donnyman is offline Find More Posts by donnyman
Reply With Quote
Old Oct 14, 2012, 09:57 AM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Thanks Donny

Coincidentally, I was thinking of using pull-pull on the model here to keep the weight down.
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 14, 2012, 02:10 PM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Link to Donny's Bulldog

Pretty incredible model and wonderful paint job. Hope mine comes out as good...

http://www.rcgroups.com/forums/showthread.php?t=902160
casor is offline Find More Posts by casor
Reply With Quote
Old Oct 15, 2012, 08:16 AM
Brooklynite In Texas
Manor, TX. USA,
Joined Jul 2008
580 Posts
The paint is rustoleum, brushed on, I was amazed how well it came out after the sprayon wrinkled when the second coat was applied.

I am considering a clearcoat to protect the pinstripng but I am not sure as to what i will use.......I also built the Williams brothers motor and have the same problems as you but ignored them as it won't be that noticeable, problem is it won't fit with this engine so I stopped.

How is your bird coming along?
donnyman is offline Find More Posts by donnyman
Reply With Quote
Old Oct 15, 2012, 11:49 AM
Failure is not an option
casor's Avatar
Boyertown, Pa
Joined Mar 2007
818 Posts
Leveling the fuselage

What a mess this makes. I used blocked 150 and then 150 on an firm foam autobody sanding pad to level the massive amounts of filler on the model. The fuselage is more "round" now but I still need another application. I also found a couple spots where the sheeting was not attd to the framework. Since the fuselage is so big, I was able to reglue these areas from the inside.

From here, I will probably brush on another coat of filler, but this time with a finer brush to avoid the brush marks that I got the last time with the broom that I used. Sanding must always go to the lowest brush mark or these will have to be filled, so it is better from here to use a soft, fine brush - or spray the filler instead.
casor is offline Find More Posts by casor
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Bulldog in LaPine Oregon MRFASTPHIL RC Tanks 8 Jun 25, 2012 09:18 PM
Alert Customer review Nitrotek and Taigen Bulldog 1/16 tank Jakke70 RC Tanks 0 Jun 05, 2012 06:34 AM
Discussion M41 Walker Bulldog battery charge mkpatrick RC Tanks 6 Feb 23, 2012 11:24 PM
Discussion Dumas Bulldog racer build. RCWarbirds Scale Kit/Scratch Built 18 Nov 22, 2006 10:19 PM
Building a bigger warbird dave_lilley Site Chat 0 Feb 09, 2003 11:22 PM