Author Topic: Dumas Crusader for nostalgia profile (Read 14701 times)

bill bischoff · « **on:** January 21, 2011, 05:29:05 PM »

Here are the first pics of the Dumas Crusader I am building for nostalgia. This was the first carrier model I ever built 25 years ago. The first one was covered in Silkspun Coverite (raise your hand if you remember that product) and dope, and powered by a Fox 36 RC MkV. It had external controls and a line slider. It was no world beater, but I usually got complete flights with it. My second contest with it was the 1986 Lake Charles NATS, where I met the "big boys" and joined NCS.

The new one will be covered in Polyspan (my first try at this) and dope. It will also have a Fox 36, although not the same engine. As evident in the photos, the bellcrank will be external and mounted in the "armpit" of the inboard wing.
There is a throttle transfer linkage through the fuselage immediately behind the engine. This is the same setup I have used on my MO-1's for years. Since I'm building it to fly in nostalgia, this model will have adjustable leadouts rather than a slider. The tank is a 3 oz Hayes RC clunk tank. Mounting it on its side puts the vent in the right place, but it also means that I will have to hold the airplane nose up to fill the tank. The tank is mounted with brass straps which are covered with heat shrink tubing to dress them up a bit. And thanks to wwwwarbird, I now have a full set of oh-so-stylish Klett wheels.

I will post more pics as work progresses, but it will probably move along slowly, as life keeps getting in the way of my hobby.

Bob Reeves · « **Reply #1 on:** January 21, 2011, 05:52:30 PM »

Really cool... Hated those things when I was in the Navy, they were either trying to suck you in the intake or blow you off the deck

wwwarbird · « **Reply #2 on:** January 21, 2011, 09:05:32 PM »

That's looking really great Bill, very nice work!

I'm guessing that you've extended the ply doublers to toughen it up for Carrier duty? Other than the obvious carrier mods, it would be interesting to know what all structure and/or substitution changes your making from the original kit design. These kits pop up on Ebay once in a while and I always catch myself thinking about snapping one up, it would just be a cool model even for sport flying.

bill bischoff · « **Reply #3 on:** January 21, 2011, 09:40:40 PM »

The doublers are actually stock. The only structural mod's to the fuselage were to add longer motor mounts and one extra maple block for the top part of the main landing gear. I also moved the main gear back about 1/2" since I plan to balance a little farther aft than the plans call for.

The kit construction is interesting. The wing is an I-beam design. The spars plug into the fuselage, and there are tip jigs which establish the anhedral and sweep back angle. The leading edges are 1/4x1/2 balsa, grooved for 1/4" dowels. The dowels plug into the fuselage in the holes you see in the photos. Yet to be cut out at the aft end of the doublers, there will be a 3/8x5/8 slot for the rear spar. behind the rear spar, the trailing edge is built up of partial ribs and 1/16" sheeting. After all that is assembled, rib slices are trimmed to length and glued in place. The stock setup is for the controls to be inside the wing, but I opted for external controls for simplicity and ease of adjustment. Then there is the full flying stabilator with dihedral.....

Some time after I built my first carrier Crusader, I did in fact build one for another club member as a two line sport model. It had a T-shaped plywood bellcrank mount installed through a slot in the fuselage, about an inch above the bottom.

Wayne, if I can find a copy shop that won't give me a hard time about copying the plans, I'll send you a set. There are half scale drawings of everything. With a little determination, you could scratch one up without a kit.

Balsa Butcher · « **Reply #4 on:** January 21, 2011, 09:50:42 PM »

I really like your throttle linkage Bill, you're still the man. May inspire me to build the F-8 kit I have stashed away.

bill bischoff · « **Reply #5 on:** January 21, 2011, 09:57:50 PM »

Go for it! With enough tail weight, it will even hang OK. Although for nostalgia, I'll have to learn how not to hang!

wwwarbird · « **Reply #6 on:** January 21, 2011, 11:09:48 PM »

Thanks for the info Bill, this is a cool project, I'll be watching this one develop.

Wayne J. Buran · « **Reply #7 on:** January 22, 2011, 04:21:02 AM »

Bill, if I remember correctly, the one and only I built had a flying stab. Is that correct and are you planning on using that. I would build one of these again accept I remember the airplane being extremely squirley. I think mine lasted six or so flights.
Wayne

bill bischoff · « **Reply #8 on:** January 22, 2011, 07:58:28 AM »

Yep! All flying stab. Wouldn't be right without it. I don't remember it as being squirrely, but you do need a tall control horn as not much movement is required. This is typical of anything with an all flying tail.

Wayne J. Buran · « **Reply #9 on:** January 23, 2011, 04:11:14 AM »

Yep, I was much younger then and didnt recognize that fact. Looking forward to more pics.
Thanks
Wayne

bill bischoff · « **Reply #10 on:** January 23, 2011, 10:02:05 PM »

I got the wing framed up today. I took out 1/2" of anhedral from each tip, as it just looked too "droopy" compared to the real airplane. I just added 1/2" to the bottom of each tip jig to raise the tips. I cut new plywood center section joiners, but the kit ones could have probably been made to work.

Next, the center sheeting, trailing edges, and tips...

wwwarbird · « **Reply #11 on:** January 23, 2011, 11:23:27 PM »

Quote from: bill bischoff on January 23, 2011, 10:02:05 PM

I got the wing framed up today. I took out 1/2" of anhedral from each tip, as it just looked too "droopy" compared to the real airplane. I just added 1/2" to the bottom of each tip jig to raise the tips. I cut new plywood center section joiners, but the kit ones could have probably been made to work.

Next, the center sheeting, trailing edges, and tips...

Right on Bill, I always go toward the more scale look over anything else. With some thought and patience this can be achieved and one can still end up with a great performing model. Some may think it silly, but it's my way of showing respect to those who flew the real things and by doing so have maintained our freedom. Beyond that, just fly the plane you've built, have fun, and be proud no matter what the result.

Wayne J. Buran · « **Reply #12 on:** January 24, 2011, 04:05:55 AM »

Bill, nice way to jig it up. Was it according to instructions? I see the .500 shim. The sweep back is stock I assume.
Thanks
Wayne

bill bischoff · « **Reply #13 on:** January 24, 2011, 07:48:04 AM »

The instructions are not super explicit on how to set everything up, Basically it says draw a line to represent where the rear spar goes, then perpendicular lines for the fuselage and tip jigs, and have at it. The rear spar goes in the big slot at the aft end of the fuse doublers, and is perpendicular to the fuse. The main I-beam spars have sweepback as well as anhedral. I was intending to build the jig on a piece of particle board, but when I was rooting around the garage at midnight looking for something suitable, the big box of balsa somebody gave me caught my eye. So the jig got built on 3/8 balsa planks! The tip jigs were glued down, and the fuse was just blocked in place.It was nice to work on the model with a solid jig to hold it. It stayed in the jig until all the top ribs were installed.

Balsa Butcher · « **Reply #14 on:** January 24, 2011, 12:28:17 PM »

Thanks for the pics Bill. I had no idea that this airplane used this construction technique and also not sure I could have figured how to make the wing jig...Cool!

Bill Little · « **Reply #15 on:** January 24, 2011, 12:41:57 PM »

HI Bill,

I have had one of those for years. It is good to know that I can actually use it in "Nostalgia" if I ever get the chance!

I was told it is too small for current Profile rules, so having a class to use it in is good news. Of course, I have to actually fly the beast sometime soon!

Big Bear

bill bischoff · « **Reply #16 on:** January 24, 2011, 02:14:38 PM »

As long as it's over 300 square inches, it's legal for profile carrier. This has been a requirement of profile carrier ever since the profile event was created. There would be no difference in this requirement for nostalgia or current AMA profile. I don't know the exact wing area, but I know it's legal.

bill bischoff · « **Reply #17 on:** January 24, 2011, 11:05:18 PM »

Boy! I just did some preliminary wing area calculations based on what's already built and what's yet to be added, and I get about 304 sq. inches. I will certainly be measuring again when the trailing edges and tips are installed. I did not realize it was so close to the minimum! Maybe I never even measured my first one, but I did fly it at the NATS, so somebody else thought it was legal, too. Who knows, I may be adding 1/4" to the wing tips!

Bill Little · « **Reply #18 on:** January 24, 2011, 11:59:01 PM »

Quote from: bill bischoff on January 24, 2011, 11:05:18 PM

Boy! I just did some preliminary wing area calculations based on what's already built and what's yet to be added, and I get about 304 sq. inches. I will certainly be measuring again when the trailing edges and tips are installed. I did not realize it was so close to the minimum! Maybe I never even measured my first one, but I did fly it at the NATS, so somebody else thought it was legal, too. Who knows, I may be adding 1/4" to the wing tips!

Hi Bill,

Thanks. I never measured it, but was told at some point in time that it wasn't "legal" for profile. Glad to know it is!

Bill

wwwarbird · « **Reply #19 on:** January 24, 2011, 11:59:38 PM »

As another option that might be of more benefit toward better flying qualities, you could add 1/4" or 1/2" wider trailing edge across the span. More wing area is usually a good thing. Just a thought.

bill bischoff · « **Reply #20 on:** January 26, 2011, 08:33:11 PM »

Wings are on! Trailing edges and tips are next.

Bill Little · « **Reply #21 on:** January 26, 2011, 08:36:07 PM »

Looks nice, Bill.

Big Bear

john e. holliday · « **Reply #22 on:** January 26, 2011, 08:56:13 PM »

Hi Bill, the old DOC here. The one JJ and I used to fly was never short of wing area according to the officials. It was built box stock and weighed a ton. It was a great trainer for the kids also. By the way did I mention your build is looking great.

bill bischoff · « **Reply #23 on:** January 26, 2011, 10:48:29 PM »

Thanks, Doc. I did a bit of calculating with the plans and got about 302 squares, so I'm sure they designed it right to the minimum. But if the trailing edge is trimmed off even a 1/16" small, across the full span that would be over 2 square inches lost. So I'll be measuring again after the TE and tips are added (but before they are shaped) to see if I need to add a little extra span. The suspense just adds to the excitement!

wwwarbird · « **Reply #24 on:** January 27, 2011, 09:56:07 PM »

Bill,

I got the plans copy in today's mail. Man, it's definitely pretty different in construction design.

Who'da ever thunk a Carrier I-Beamer??? Neat model though!

Just curious, I know the actual model is bigger than shown here on these plans, but is this copy of the plans the actual size of the original plan or is it shrunk down? (Is that confusing or what???

)

Thanks!!!

W.W.

bill bischoff · « **Reply #25 on:** January 27, 2011, 10:32:48 PM »

That's a full size plan. The plane is shown exactly half scale. There's nothing that actually gets built over the plans, so I guess they figured the drawings didn't need to be full size. You could certainly blow it up double size to scratch build one. You might even consider changing the wing structure...

wwwarbird · « **Reply #26 on:** January 28, 2011, 10:20:36 PM »

Thanks Bill, just curious.

bill bischoff · « **Reply #27 on:** January 30, 2011, 09:17:32 AM »

Here's the latest pix. The wing ended up just under 301 sq. inches after I trimmed 1/8" off the too thin trailing edge. Attention now moves to the stabilator. Nothing is glued yet. The surfaces need to be shaped and the alignment double and triple checked. I'm not 100% sure this is the control horn setup I will use. I may go with a 1/4" flat brass arm silver soldered to the wire instead. A simple nylon horn would work, but seems to lack "elegance".

Wayne J. Buran · « **Reply #28 on:** January 30, 2011, 11:17:06 AM »

So I see the long elevator horn. Can't tell how tall it is? I never did like the color scheme on the original kit box. How about a nice Navy two tone gray ala Bob Reeves, a new trend. I think i need to track down a kit for grins. Keep the pictures coming please.
Wayne Buran

bill bischoff · « **Reply #29 on:** January 30, 2011, 11:38:05 AM »

It's a 1 1/2" 4-40 bolt. It's the longest I could find that was fully threaded. I think it will be long enough. I didn't want to use all-thread because it's too soft. If it looks like too much movement once I hook it up to the bellcrank, I guess I'll go with a brass arm.

Bob Reeves · « **Reply #30 on:** January 30, 2011, 03:09:57 PM »

How about VF-211 Checkmates This was the F8 squadron that was aboard the USS Hancock when we were flying FJ-4's and later A4's.

wwwarbird · « **Reply #31 on:** January 30, 2011, 03:46:06 PM »

Lookin' great Bill, first real-life photos I've seen of this design, it's cool. No adjustable rudder though? I don't know jack about Carrier class rules, maybe it's not allowed in what you plan to fly.

bill bischoff · « **Reply #32 on:** January 30, 2011, 06:42:58 PM »

Here's a little more detail on the stabilator. Note the use of more jigs for proper alignment. The wing jig is still quite useful in holding the airplane square to the table while aligning the tail.

As for the kick out rudder, my first Crusader actually had one, but I didn't think it did any good, so I didn't bother this time. Also a moderately interesting coincidence, my first one had a red and white checkerboard rudder!

skyshark58 · « **Reply #33 on:** January 30, 2011, 07:54:42 PM »

Bill, If you need an extra long elevator horn I'll make you one to your specs from aircraft aluminium. Send me a PM. Mike

wwwarbird · « **Reply #34 on:** February 07, 2011, 07:47:58 PM »

What's the latest Bill?

bill bischoff · « **Reply #35 on:** February 07, 2011, 08:01:06 PM »

Thanks for asking!

All the construction is done, and now I'm just waiting for some warmer weather so I can begin covering and finishing. Unless I screw up terribly, the next thing to show will be my first attempt at polyspan. Based on what I've read, I am planning to not go much past the tip ribs with the polyspan, and use silkspan on the tips instead. If it all goes south, it'll be Monokote!

wwwarbird · « **Reply #36 on:** February 07, 2011, 09:07:20 PM »

Sounds good.

I'll try and offer a few tips, what works for me anyway...

Even cutting Polyspan can be a little tricky. I always start with a BRAND NEW #11 X-acto. I lay it down on a nice smooth piece of cardboard so it doesn't slip around and cut while using a straightedge. Check, double and triple check to make sure you have the correct side up when you lay it on the wing.

Then check again.

I'll cover the wing as usual, running it a couple inches past the end rib so that you have something to hold onto. Once I get it well attached all around the perimiter, I let the clear dry at least 24hrs. Next I'll come back and shrink it with the heat gun, carefully. Shut off a light or something in your shop to get yourself some shadows to watch as you tighten it, this really helps a lot. Sneak up VERY carefully with the heat settings and application until you get used to using the stuff, be patient. Once I get it tightened up then I'll dope it on to the rest of the ribs and sheeting. After that I'll trim it back flush with the end rib. Then, as the last thing, I'll do my wingtips with medium silkspan. I overlap it about an inch back over the Polyspan, and then move on with the rest of the clearcoats on the whole wing.

Polyspan definitely takes some getting used to, but I won't use anything else anymore. When it's all finished it's pretty tough too, which should be good for the abuse Carrier planes have to take.

Hope this helps!

Bill Little · « **Reply #37 on:** February 07, 2011, 09:11:05 PM »

Wayne, I think you "covered" that pretty completely!

Big Bear

bill bischoff · « **Reply #38 on:** February 08, 2011, 07:22:29 AM »

Thanks for the tips. Do you cut it to the correct chord and just a bit long in the span? In other words, are the leading and trailing edges cut to size first, or do they "hang over" and get trimmed off later like the tip?

Bob Reeves · « **Reply #39 on:** February 08, 2011, 10:13:13 AM »

Quote from: bill bischoff on February 08, 2011, 07:22:29 AM

Thanks for the tips. Do you cut it to the correct chord and just a bit long in the span? In other words, are the leading and trailing edges cut to size first, or do they "hang over" and get trimmed off later like the tip?

I trim it right after the attachment dope has been put on then dope the cut edges down.

Bill Little · « **Reply #40 on:** February 08, 2011, 11:37:39 AM »

Hi Bill,

I guess the application varies like any other covering. I apply it exactly like silkspan (but not wet LOL!!) Oversize and trimmed after it is attached with a single edge razor. Both sides of a panel get covered before any shrinking, of course.

The one caveat is that if you do ANY sanding on it before enough finish is applied you WILL get the "fuzzies"! Thin CA is about the only cure for that once they occur as far as I have found.

Big Bear

Bob Reeves · « **Reply #41 on:** February 08, 2011, 04:52:52 PM »

I discovered a little trick to killing the fuzzes when I built my Skylark. Smear some clear dope over it, let it dry then very lightly hit it with 400 sandpaper. Just enough to cut off the fibers sticking up and no more. The mistake I was making was being too aggressive with the sandpaper and just raising more fuzzes, a light touch and one or two swipes is all that it takes.

wwwarbird · « **Reply #42 on:** February 08, 2011, 06:04:42 PM »

Quote from: bill bischoff on February 08, 2011, 07:22:29 AM

Thanks for the tips. Do you cut it to the correct chord and just a bit long in the span? In other words, are the leading and trailing edges cut to size first, or do they "hang over" and get trimmed off later like the tip?

I do the bottom of the wing first by lining up the L/E edge of the material to land naturally along the centerline of the L/E, and then just let it hang over the T/E. Depending on the shape of the wing, I might do the whole bottom at once, or in halves, same with the top. Starting with the bottom, I attach it and then trim it off along the T/E. Then I do the top lining up the L/E edge of the material to overlap the bottom piece by a 1/2" or so, and again just let it hang over the T/E. I attach it, and then trim off the T/E. I never worry about having it wrap around the T/E, I just trim it off along the top rear most edge of the T/E.

Bill Little · « **Reply #43 on:** February 08, 2011, 07:11:10 PM »

The stuff is rayon, and a derviative (or it's just the same) as "sport coat lining". The Burlington plant about 15 miles from here makes it, or at least did. LOL!!

Big Bear

john e. holliday · « **Reply #44 on:** February 09, 2011, 08:46:13 AM »

Why do people use silkspan on the wing tips? I use the scrap peices of Poly-span if I don't do the tips with the main panel. I also make sure that I have severqal coats of dope on the material. Usually do the edges with extra coats. Where the over laps are is where I sand very lightly. When the dope starts to get a little sheen then I add Talc to the dope. Do two coats and then lightly sand. The ones I am working on now I have only sanded the rough edges with more dope. Every body has their way of doing things and that is where expeirmentation comes in.

Bill Little · « **Reply #45 on:** February 09, 2011, 10:37:47 AM »

Quote from: john e. holliday on February 09, 2011, 08:46:13 AM

Why do people use silkspan on the wing tips? I use the scrap peices of Poly-span if I don't do the tips with the main panel. I also make sure that I have severqal coats of dope on the material. Usually do the edges with extra coats. Where the over laps are is where I sand very lightly. When the dope starts to get a little sheen then I add Talc to the dope. Do two coats and then lightly sand. The ones I am working on now I have only sanded the rough edges with more dope. Every body has their way of doing things and that is where expeirmentation comes in.

HI Doc,

Some people hare just luckier than others I guess!!

I cannot remember a model airplane that I have ever covered the tips separately on. I just keep going back and forth and pulling, stretching, doping, etc........ But, then, I seem to be one of the lucky ones.

Big Bear

wwwarbird · « **Reply #46 on:** February 09, 2011, 06:32:57 PM »

Some folks are able to do perfect tips with Polyspan, I'm not lucky enough to be one of them. By choice, I simply don't want to burn up a bunch of the stuff experimenting.

I do my tips with medium silkspan only because it's my preference. I'm not satisfied if there is even a single tiny little wrinkle in my covering jobs. I just do what works for me.

wwwarbird · « **Reply #47 on:** February 19, 2011, 11:01:09 PM »

Ten days and no updates???

bill bischoff · « **Reply #48 on:** February 20, 2011, 05:56:42 PM »

Got a few thin coats of clear on the wood last weekend, now ready for covering. Out of town last Tuesday through this evening. Still too dark after work to dope outdoors, so I'll have to wait until my next day off. I guess I can at least cut the covering ahead of time.

bill bischoff · « **Reply #49 on:** February 25, 2011, 01:26:42 PM »

Got the polyspan put on today. It seemed pretty straightforward and user friendly. It's real tempting to break out the heat gun and start shrinking, but I will make myself wait. Maybe some new pix on Sunday.