Author Topic: Brodak F-51 kit build thread (Read 13310 times)

John Fitzgerald · « **on:** December 12, 2011, 07:38:52 PM »

Going to start on this after Christmas holiday. I think I will carefully document the construction of this one.
Might use a GP Thunder Tiger .25 on it. Hopefully I can build it fairly light, but I tend to go for strength.

john e. holliday · « **Reply #1 on:** December 13, 2011, 05:53:00 AM »

Build only as strong as needed. The lighter the plane, the less inertia when they crash or bounce off the ground.

Bill Little · « **Reply #2 on:** December 13, 2011, 04:51:23 PM »

Hi John,

I am guessing this is the remake of the Sterling Profile and not the 48" WS P-51B Warbird profile. If so, the .25 should be real good for it.

Big Bear

John Fitzgerald · « **Reply #3 on:** December 13, 2011, 06:57:42 PM »

Yes, re-make of Sterling F51. Had one back in mid 1970's with .35 power (I think McCoy red head, can't remember). I once flew it in an impromptu combat match. It was pretty fast for a sport plane. I don't want to over power it this time.

Geoff Goodworth · « **Reply #4 on:** December 14, 2011, 12:58:08 AM »

John, my Shoestrings are 395 sq in and weigh about 29 oz. An FP 20 is plenty of power. If I were to get involved with the F-51, at 323 sq in, I think a modern 15 would be quite adequate. What do others think?

jim gilmore · « **Reply #5 on:** December 14, 2011, 01:35:11 AM »

who is Bordak ?

Bill Little · « **Reply #6 on:** December 14, 2011, 03:14:00 AM »

Quote from: Geoff Goodworth on December 14, 2011, 12:58:08 AM

John, my Shoestrings are 395 sq in and weigh about 29 oz. An FP 20 is plenty of power. If I were to get involved with the F-51, at 323 sq in, I think a modern 15 would be quite adequate. What do others think?

HI Geoff,

There has been at least one Ringmaster S-1 that has been successfully powered by a .15FP. An OS .20FP would be plenty and what I would probably use. Keeping the kit built model light enough for a .15 might not be an easy task. The .20-.25 will help in that area. John can use a low pitch prop and keep the "speed" down yet still have some extra punch if the wind comes up.

Big Bear

John Fitzgerald · « **Reply #7 on:** December 14, 2011, 06:11:25 AM »

Quote from: jim gilmore on December 14, 2011, 01:35:11 AM

who is Bordak ?

Sorry, I meant Brodak. I corrected the original post.

john e. holliday · « **Reply #8 on:** December 14, 2011, 09:38:42 AM »

Well now I don't feel alone. Keyboard problems, keep getting characters not wanted or misplaced. One of the reasons it takes me so long to post. Even then after editing some does get thru. Don't forget the pictures of thebuild.

Bill Little · « **Reply #9 on:** December 14, 2011, 10:12:01 AM »

Quote from: John Fitzgerald on December 13, 2011, 06:57:42 PM

Yes, re-make of Sterling F51. Had one back in mid 1970's with .35 power (I think McCoy red head, can't remember). I once flew it in an impromptu combat match. It was pretty fast for a sport plane. I don't want to over power it this time.

Hi John,

As I am sure you know, the *modern* stunt run is a high rpm low pitch (~4") set up. Get the engine running in a solid but not peaked 2 cycle and adjust prop pitch to get the speed you want. It's not about power, you want all of that that you can get, but more about how you run the engine.

BIG Bear

John Fitzgerald · « **Reply #10 on:** December 14, 2011, 01:00:29 PM »

Quote from: john e. holliday on December 14, 2011, 09:38:42 AM

Well now I don't feel alone. Keyboard problems, keep getting characters not wanted or misplaced. One of the reasons it takes me so long to post. Even then after editing some does get thru. Don't forget the pictures of thebuild.

It is not a PA plane. Are you sure members would want postings of the build? If people are interested I will post them when I get started after Christmas, but I don't want to bore anyone with non useful information.

Bill Little · « **Reply #11 on:** December 14, 2011, 10:01:25 PM »

Quote from: John Fitzgerald on December 14, 2011, 01:00:29 PM

It is not a PA plane. Are you sure members would want postings of the build? If people are interested I will post them when I get started after Christmas, but I don't want to bore anyone with non useful information.

Hi John,

It is always good to see a build in progress. Go ahead and post a series of your build when you get started!

Big Bear

jim gilmore · « **Reply #12 on:** December 14, 2011, 11:40:29 PM »

Photo's,photo's,photo's.......
We love to see anything being built.....

John Fitzgerald · « **Reply #13 on:** December 30, 2011, 06:50:45 PM »

I just started on it this evening. Got out my building board for the first time in 10 years topped with a new piece of sheetrock. I think I will build this plane with fixed flaps vs moveable like the kit suggests. I don't see any significant gain from movable flaps on a design like this one with only 323 squares. If I am way off, please let me know. I will try to build it as light as possible. The kit has good, light wood.

EddyR · « **Reply #14 on:** December 30, 2011, 08:09:49 PM »

With good controles flaps make a big difference on the Mustang. I built quite a few and mine had good controles. Most people used the Sterling controles and they were very poor. The kits came with short plywood horns.
Ed

Steve Helmick · « **Reply #15 on:** December 30, 2011, 08:16:44 PM »

What are "controles"? Can't resist getting in on the fun. I figure it must be hispanish for "controls"?

Steve

Dennis Moritz · « **Reply #16 on:** December 31, 2011, 12:59:34 AM »

Sounds about right for an LA 25, if you haven't bought an engine yet. The LA25s are no fuss no muss, if propped right and run with good fuel. I wouldn't sweat a super light build, unless you plan to fly this in competition. I've seen a few Ringmasters powered by Fox 35s that were given the full lightness treatment. One even had a hollowed out fues. Split into two halves, as much interior wood carved out as practical, then glued back together. Great Old Time bird that became a mascot for our club, handed off, and handed off again. The bird started out at 22 ounces or so, wound up, after an illustrious competition record and many spectacular and abusive crashes, at 36 plus. Even at that weight it placed in the money at Brodak. Must have been the chicken bone used to offset the tank.

But, like I said at the beginning, if the primary use will be fun flying, forget about the carving up to lighten program. No need. Also, easy to make the plane flimsy and prone to breakage in a hard landing or hard g pull outs. At Brodak one year a Brazilian team showed up with many ultra light Ring a Dings. Seemed like half of them folded up their wings. Usually the Brodak wood is fine enough to build first class sport models. Built according to the plans with no extra chopping away.

Bill Heher · « **Reply #17 on:** December 31, 2011, 12:43:12 PM »

OS .25 would be an excellent choice, have used them on S-1Ringmasters, FliteStreaks,, ShoeStrings etc. Itis a great substitute for a for a Fox or McCoy .35, and runs well with a muffler. As stated above, nice solid "fat" 2-cycle run, and play with props to get speed / thrust to match flying style you want.
A Hayes 2ox plastic tank with clunk pickup and muffler pressure works well, uni-flo is good, and you won't go super lean if the muffler line some off.

John Fitzgerald · « **Reply #18 on:** December 31, 2011, 06:00:37 PM »

Any more opinions as to whether I should build the moveable flaps?

Geoff Goodworth · « **Reply #19 on:** December 31, 2011, 07:17:21 PM »

John, if you are going to buy a new LA 25, replace the screws with socket head cap screws and be very careful about the backplate screws.

I was very surprised at how they were just nipped up tight enough. I can see how people used to tightening cap screws onto aluminium backplates could get into trouble. If you want to replace the backplate, the Thunder Tiger GP 25 backplate and gasket fit and are quite economical from Tower.

Jim Kraft · « **Reply #20 on:** December 31, 2011, 07:32:16 PM »

I think the Brodak kit should build up pretty light, and I think he changed the leading edge to a smaller square, and also uses top and bottom spars instead of the center spars of the original. Since it will be lighter, I would say it will probably fly just fine without flaps. I built this original kit a few years ago, and with a Fox 35 and flaps, it weighs 32 oz. It fly's just fine as long as you don't push it to hard in the corners. Yours should be a fun plane.

John Fitzgerald · « **Reply #21 on:** December 31, 2011, 07:43:10 PM »

I have the wing built except for center sheeting and tips. It is very easy to twist, unlike some others I have built. It almost seems too flimsy. Yes, it has a C-type leading edge with 3/16 sq balsa sheeted with 1/16 balsa. One of the spars was broken and very weak anyway. I replaced it with some stock on hand. The belcrank bolt was a 4-40, with 6-32 nut and #6 washers. Replaced that with a 6-32 allen bolt and nylock nut. Good thing I have a hardware store in my house (that's what my neighbor says). If I try to stiffen the wing with a lot of webbing it might get too heavy.

Dennis Moritz · « **Reply #22 on:** December 31, 2011, 08:15:12 PM »

Web it with light would. Does this Brodak plane use capstrips? They help stiffening. Does the 1/16" go from the leading edge back to the spar? If that's so, webbing would make a D-tube. Should be plenty stiff. I always web between the spars. When light wood is used, doesn't seem to effect weight much. Personally, I wouldn't compromise on the strength of wing structure.

John Fitzgerald · « **Reply #23 on:** December 31, 2011, 08:24:15 PM »

Here are some pics of the build so far.

Jim Kraft · « **Reply #24 on:** December 31, 2011, 09:07:13 PM »

Very nice work John. I think when you get the center section sheeting installed it will be stiffer. The original, as you probably remember, had the ball bat wood large leading edges, and the rock hard center spars and trailing edge. Those came out reasonably stiff, but also heavy. The Ringmaster was pretty much the same. If you cover it with silkspan and dope, I think it will be plenty stiff and light. If you are using plastic covering, you might want to beef it up a little more as they don't stiffen things up as much.

Dennis Moritz · « **Reply #25 on:** December 31, 2011, 09:59:22 PM »

If you wish to add strength, looks like either webbing between the spars, or webbing the leading edge, would help. There's also the possibility of trailing edge webbing. Which I always do. Also keeps the wing truer, less prone to warps. Structurally C-tube wings make me wonder about strength issues, flex, breakage, durability, long term trueness of the balsa fabrication. I close up the back end with light wood for those reasons. A D-tube is way stiffer. Seems that way to me. Similar to a triangle. A very stiff shape. The wings that failed on the Brazilian planes used leading edges similar to the one pictured. I don't think that's the best way to go. They may have used the classic Ringmaster spar through the back end of the ribs. No strength there. The conventional spars used in this model, much better. The original Sterling planes had thick hard leading edges. I had a Yak way back when. Very similar design. The leading edge of the updated Brodak model would be less strong. Especially if you've got some contest light wood wrapping the front of the wing. I've built a number of Brodak kits. At times the quality of the wood has been shockingly good. Very light. If the leading edge planking it of that quality, I would definitely close up that C and make it a D.

John Fitzgerald · « **Reply #26 on:** December 31, 2011, 10:45:43 PM »

Dennis,
I have now added 1/16 light balsa webbing between the spars on all but the outboard ends, so as not to interfere with the weight box and adj lead outs. I think I will also close up the trailing edge, which will not use much wood. I have a Sterling Ringmaster that I built several years ago. It has a formed leading edge about 1/2 x 3/4 inches. I replaced most of the wood and built it right.
On the current build, I am planning to use the Brodak plastic covering on the wing, at least. I may dope the rest, haven't decided. I have a GP Thunder Tiger .25 I could use on it, but if I can swing it I want this to be my first electric. At any rate, I will build it so glow can be used.

Dennis Moritz · « **Reply #27 on:** January 01, 2012, 06:58:39 AM »

John,
All that sounds good to me. I'd close up the back end of the leading edge C, as well. Cutting the rectangles precisely can be a pain. But. An alternative to fitting the rectangles inside is to glue them outside the back end of the C. That way they can be trimmed to fit easily. After the CA wicks. Thunder Tiger should run well, similar to FPs, I believe. Run them up in the RPM range with a 9x4. No screaming, but in a 2 stroke. Tho, if your taste runs that way, let the engine scream. I'm sure these engines will do that. Folks in my club have taken to abusing LA25s with a bladder on speed limit combat planes. Amazing the racket these engines will make when the needle valve is twisted in. That's how we run FP25s. Either kind of fast or torture the little beast. Tongue mufflers with a lot of holes, .265 (6mm I think) venturi. These are sport planes. Sport planes are fun. Fly them kind of fast to very fast. At these speeds the planes will stay out on the lines, do the tricks, often feel flyer friendly. I think the value of sport planes for sheer fun is overlooked by some of us, as we worry over legit stunt war wagons that will usually need extensive trimming and engine tuning. Yeah. Stunters designed for the job can do the pattern better, will do the pattern better, if straight, trimmed and matched to reliable and appropriate power. But most of the time they are continuing evolving as are the skills of the pilot. Which means serious attention to details and closely observing how we do the tricks. Sport planes on the other hand are a pleasure, a hoot, often year after year.

john e. holliday · « **Reply #28 on:** January 01, 2012, 07:49:51 AM »

Once you get the wing covered you will be amazed at how stiff it will get. A little something I do to all my planes is cut another peice of ply to put on the other end of the mounting bolt of the bellcrank. Makes for bullet proof mounting of the bellcrank.

Brian Browning · « **Reply #29 on:** January 01, 2012, 08:16:06 PM »

Don't worry about using an iron-on. I have a Brodak Yak that is the companion piece to the Mustang. I built it per plans (except for wing mounting the landing gear and adding dihedral for looks), and covered it with doculam painted with Rustoleum. Nice tough, light, stiff wing. No worries about flexing. I'm using an LA .25 also. Fixed flaps upon the recommendations of several veteran Sterling builders and flyers. I just wanted a fun sport flyer, and I've never built a model of anything those "Godless Communists" flew in WWII.

Happy New Year, y'all,
Brian

John Fitzgerald · « **Reply #30 on:** January 01, 2012, 09:19:15 PM »

I have finished building the wing. Added 1/16" sheet webbing between spars where possible, closed up the trailing edge, and D-tubed the inner six bays, all with light 1/16" balsa. It's much stiffer now, but not as stiff as my Twister, where I used spruce spars. The weight box was not right for this plane, had to cut it down 3/8 inch shorter. Also, the eyelets for the leadouts are too small for the leadout wire. I used 3/32 o.d. copper tubing to bush them, like I did on the bellcrank. Also made up some adjustable leadouts. Have now started on the fuselage. Hopefully more pics tomorrow.

Phil Spillman · « **Reply #31 on:** January 03, 2012, 02:34:42 PM »

I John, I have had two of these in the "modern sense" ie beyond 1951/52 and have used the flaps on both! I am very happy that I did this since the wing is quite thin and uses all the extra help it gets! The most recent build, a rebuild from 1974, I covered with Flat Mono Coat and used mono coat hinges as well. These go on under the main covering using a edge wrap, my term for giving the hinges something to hold on to rather than just wood; this also helps to seal out the ooze of goop under the film! Nothing worse than oozed goop to ruin your day! I did the rebuild from the pieces kept in an old paper bag for a decade or more and then made it into a B model as opposed to a D model. With the flap and elevator hinge lines fully sealed from having used root to tip MC hinges the plane flies just fine! My power for these has been the LA .25 and FP .20 engines running on muffler pressure. These are truly fun planes to stunt! Both of mine perform the full PA pattern with ease-- not too much finesse-- but maximized fun!

Phil Spillman

Bill Little · « **Reply #32 on:** January 03, 2012, 05:34:55 PM »

I have a Yak 9 just waiting on me to build the wing. I used a Sterling kit and copied it with lighter wood. Going to power it with a Veco .19BB which I know will be PLENTY of power.

BIG Bear
RNMM/AMM

John Fitzgerald · « **Reply #33 on:** January 03, 2012, 07:40:58 PM »

No more pics yet. I have all the major pieces together as assemblies, but not yet together as a complete unit. I have to wait for some warmer weather at this point hopefully late in the week to be able to put Balsarite on the wing, flap, and tail surfaces so they can be covered with plastic. I like Balsarite because it makes the covering adhere very well, stiffens the balsa somewhat, and is completely fuel proof, in case any fuel residue creeps under the covering. I am going with hinges made of the plastic covering material (Brodak brand), so at least the trailing edges of the wing and stab have to be covered, along with the flaps and elevator, before I can apply the hinges. Covering the rest of the wing can come last. I am going to dope the fuselage and vertical stab. Those parts would be difficult for me to cover with plastic, particularly the nose. I tried to cover a fuselage once with plastic. It was a full fuse model called "Fancy Pants" and it came out looking really crappy. That turned out OK because the pushrod joint came loose and it crashed after only a few flights.

Steve Thomas · « **Reply #34 on:** January 03, 2012, 07:46:02 PM »

I've built quite a few models round this size, and I'd go for the movable flaps. Not too much deflection though - maybe only about half the elevator throw.

One of mine is an MC72-style thing, a bit like a little Tucker Special. 42" span, 340 sq.in and about 26 oz. it flies really nicely with an Enya SS15 on 52' lines, so any decent .15-.25 should be fine on your F-51.
Steve

Brett Buck · « **Reply #35 on:** January 03, 2012, 10:14:51 PM »

Quote from: Bill Little on December 14, 2011, 03:14:00 AM

There has been at least one Ringmaster S-1 that has been successfully powered by a .15FP.

A lot more than one! That would be my engine of choice for a Ringmaster - use a 9-4, 8.5-4 or 8.5-5. With a 20 or 25, slowing it down is the big problem. A Veco 19 is plenty, as well.

If this is a re-issue of the old Sterling kit, you need to keep it feather-light for the wing, not the engine. I think the Ringmaster flies better than the P-51.

Brett

John Fitzgerald · « **Reply #36 on:** January 04, 2012, 05:57:30 AM »

I am building it with moveable flaps. .25 TT engine with R/C carb wired open is available as first option. Will have to wait for warmer weather days to paint as I cannot dope in the house.
Btw, I changed the thread title a little.

Brett Buck · « **Reply #37 on:** January 04, 2012, 05:54:21 PM »

Quote from: John Fitzgerald on January 04, 2012, 05:57:30 AM

I am building it with moveable flaps. .25 TT engine with R/C carb wired open is available as first option.

The engine will work fine that way. On the flaps, make sure you can adjust the flap/elevator ratio. Making the flaps move on these sorts of models can be a mixed blessing. It helps somewhat on the lack of lift but the tail is pretty tiny for a flapped airplane. I would suggest you start with the flap/elevator ratio about 1:2 (twice as much elevator as flap movement) and adjust from there.

Brett

John Fitzgerald · « **Reply #38 on:** January 04, 2012, 07:05:24 PM »

I soldered on an adjustable clevis threaded end to a thicker pushrod than came with the kit. It goes from bellcrank to the flaps, and another one will go to the elevator. On all my planes so far, I have made the flap throw 1/2 or less of the elevator.
Even my scratch built design with the huge tail flies better eith less flap throw; less tendency to stall. I don't have limiter stops on the bellcrank, but I fly well enough not to over-control. This is my first build in about ten years.

Brett Buck · « **Reply #39 on:** January 04, 2012, 07:46:10 PM »

Quote from: John Fitzgerald on January 04, 2012, 07:05:24 PM

I don't have limiter stops on the bellcrank, but I fly well enough not to over-control. This is my first build in about ten years.

You never want a limiter - if you want less overall throw, slow the controls down, don't block them. The clevis and soldering makes me very nervous but I think you know the risks.

Brett

John Fitzgerald · « **Reply #40 on:** January 04, 2012, 08:00:52 PM »

Brett,
The soldering makes me nervous too. I have had a Brodak rod joiner come loose due to cold joint, and crash the plane. This time, I used a propane torch on low, cleaned the rod with sandpaper, got the rod fluxed and pre-tinned with solder, filled the hole in the brass solder-on piece with liquid solder, jammed in the rod while still heating, and wiped it off with a rag, like sweating a pipe. I don't think this one will come loose. This kit uses a solder on joiner on the rod to the elevator, but I think I will use a single piece rod, and try to bend it to correct length, or use a clevis. I have a very difficult time getting flaps and elevator level at the same time unless one of the positions is adjustable.

Brett Buck · « **Reply #41 on:** January 04, 2012, 08:36:46 PM »

Quote from: John Fitzgerald on January 04, 2012, 08:00:52 PM

This kit uses a solder on joiner on the rod to the elevator, but I think I will use a single piece rod, and try to bend it to correct length, or use a clevis. I have a very difficult time getting flaps and elevator level at the same time unless one of the positions is adjustable.

You can use a conventional carbon pushrod with ball links at each end, solves both problems. Ball links, properly used, are bulletproof.

Brett

John Fitzgerald · « **Reply #42 on:** January 04, 2012, 08:48:57 PM »

Brett,
I am old school, used to music wire pushrods with bends or solder-ons, and am not familiar with carbon pushrods. I just looked them up and Brodak seems to have them, and the inserts. I suppose the ball ends go on in place of or in addition to the insert? I have already closed up the wing on this one. The center sheeting is well glued. I will try the carbon pushrods with my next build, whenever that is. Might build another Banshee sometime this year.

John Fitzgerald · « **Reply #43 on:** January 07, 2012, 03:02:16 PM »

I have always had a problem with oil and gunk building up in the hole where the flap joiner goes through the fuse on profiles. I would like to avoid it on this model. I did not find anything on this in the threads, so I hope it's not a re-hash. Maybe it's not really an issue. ?
Anyway, here's a pic of where I am now on the build.

Brett Buck · « **Reply #44 on:** January 07, 2012, 04:40:33 PM »

Quote from: John Fitzgerald on January 07, 2012, 03:02:16 PM

I have always had a problem with oil and gunk building up in the hole where the flap joiner goes through the fuse on profiles. I would like to avoid it on this model. I did not find anything on this in the threads, so I hope it's not a re-hash. Maybe it's not really an issue. ?
Anyway, here's a pic of where I am now on the build.

I think most people use brass tubing on the cross-wire, use that as the bearing and that lets you glue/fillet/paint right up to it, so there's no gaps for crud to accumulate. I would make it span the entire distance between the flaps, say, an inch or so. That will give you about a quarter-inch of tubing on either side of the fuselage which can be filleted over.

Brett

John Fitzgerald · « **Reply #45 on:** January 07, 2012, 06:18:26 PM »

Brett, thanks for your suggestion.
Putting a brass tube on would not work unless one bends his own cross-wire for the flaps. With the pre-bent one that came in my kit, there is no way to put a bearing over it. Next time, I will avoid this problem and bend my own cross-flap wire with a piece of tubing on it. My next model will be better, with carbon pushrods, flap/elevator bearings, etc. This one is pretty much kit stock except for extra bracing in the wing, adj leadouts, wrapped / bushed leadouts, and a landing gear joiner tube. The kit books don't come with a lot of tips to make the model better. Wonder if Brodak takes suggestions on these things? Just a few pennies more hardware and a few tips in the book could eliminate the source of a lot of little annoyances.

larry borden · « **Reply #46 on:** January 07, 2012, 06:54:46 PM »

I build a cover for the pushrod hole out of scrap balsa. Two pics of what I'm talking about.

Brett Buck · « **Reply #47 on:** January 07, 2012, 07:13:49 PM »

Quote from: John Fitzgerald on January 07, 2012, 06:18:26 PM

Brett, thanks for your suggestion.
Putting a brass tube on would not work unless one bends his own cross-wire for the flaps. With the pre-bent one that came in my kit, there is no way to put a bearing over it.

You can split a tube one size too big with a Zona saw, bend it open, slip it over, then close it back up. Maybe a little bit more effort than it's worth at this point, but certainly doable. Then just glue it to the TE.

Quote

Wonder if Brodak takes suggestions on these things?

Don't tell him it came from me!

Brett

larry borden · « **Reply #48 on:** January 07, 2012, 07:18:39 PM »

Mis read you question. Thought you meant the hole in the wing where the push rod comes out of the wing.

john e. holliday · « **Reply #49 on:** January 08, 2012, 07:33:34 AM »

If you enlarge the distance between the flaps and the fuselage, this will work. I cut fairing peices to fill the gap I made. Yes there is a gap between it and the wing. I then lay a strip of fiber glass along the joint of the wing and fuse all the way to the end of the peice I just put in between the flap and fuse. Also as has been stated, I cut a peice of scrap balsa to make a hood over the pushrod exit.

John Fitzgerald · « **Reply #50 on:** January 08, 2012, 09:43:33 AM »

Thanks. I split a piece of 1/8" ID tubing, slipped it over the flap joiner, and squeezed it back down with gap at the back. Was able to fill right up to it. Flaps, elevator, and horiz stab are covered. Wing ready to cover. Fuse and other exposed wood have two coats of Sig clear dope based sanding sealer on them. 11.5 ounces right now without motor, prop, tank, landing gear, horns, tip weight, and elevator pushrod. All the gear not on the plane yet weighs 15 ounces, so right now I am at 26.5 ounces. Not too good.

Jim Kraft · « **Reply #51 on:** January 09, 2012, 10:02:36 AM »

John; Mine weighs 32 ounces, and fly's pretty well with a Fox 35. I do have 1 to 1 flap elevator, and unless I crank on the handle really hard, it corners just fine. It will be a fun plane even if it is a little on the porky side. Just keep the finish as light as you can.

Dick Pacini · « **Reply #52 on:** January 09, 2012, 01:16:54 PM »

John, the problems you had with the kit; spar, mismatched hardware, weight box and leadout bushings should be reported to John Brodak. I am sure he would take corrective action on the kits in stock and make it right with you.

John Fitzgerald · « **Reply #53 on:** January 09, 2012, 06:26:10 PM »

The hardware problems were really not that big a deal. I have built several planes before, just not recently, and this time had replacement stuff in the house already, plus tools to fix the other problems. I agree not everyone would be so lucky. If you guys think that John Brodak would be interested, I will compile a list of problems with the kit and errors in the book and send it to him. I will do it in as nice a way as possible, and publish it here also if anyone would be interested. If I get a response, I will summarize that on here too.

BTW, the plane gained just 0.3 ounces with the final coat of sealer. The three coats of Sig sealer are probably equal to three coats of clear. I am thinking one coat of clear, one color, let cure, and top with another clear, and it will achieve the 15 foot finish I am shooting for, and be fuel proof enough for the 10% nitro I use. After all, it's only a fun flier.

Dick Pacini · « **Reply #54 on:** January 09, 2012, 07:24:59 PM »

My experience with Brodak is that they will absolutely bend over to satisfy a customer and make it right. They will correct any known kit problems. I bought a P40 ARF that had a bad spot in the wing. They replaced the wing with another, but that one had controls that would hang up. They furnished another wing that was fine.

I had a couple of mishaps and asked if I could buy some replacement covering. They sent me some no charge. Another mishap resulted in the stab being broken in half. I had gotten CA in the hinges and they were too stiff, resulting in a loss of control. I contacted Brodak about the problem and they sent a new stab, new elevators, new horn and new hinges. No charge.

By all means let them know of your problems. They will make it right and correct any stock.

Dennis Moritz · « **Reply #55 on:** January 10, 2012, 01:42:25 PM »

Stop already. As my friend Dan Banjok says (all the time), GO FLY!

John Fitzgerald · « **Reply #56 on:** January 10, 2012, 07:18:01 PM »

I put on the first coat of Sig Lite Coat clear a while ago. All the wood looks shiny and sealed now. I think I will give it a few days to cure, then put the color on. Sig Silver on fuse with yellow vertical fin like on the kit box.
Another mistake I found in the instructions: They say to temporarily put the landing gear into place, glue the fairings onto the front of the wing over the landing gear wire, then remove the landing gear. If I had followed that, I would not be able to remove the landing gear without slotting the fairings, as the half-round in the fairing exactly matches the lg wire. Looks to me like the fairings need to go on last, or maybe not at all.

John Fitzgerald · « **Reply #57 on:** January 12, 2012, 08:36:04 PM »

Sealed and ready for color.

Here is the message I sent to John Brodak via his website:

John,
I purchased the F-51 Mustang (Sterling remake kit) from you last month.
There were a few minor problems with the kit that I feel should be checked or corrected for this kit.
I don't expect you to do anything on the one I have as I have already fixed the problems during the build, and am happy with my fixes.

1. One of the main spars was broken when I first opened the box due to a bad spot in the wood.
2. The bellcrank bolt was a 4-40 and did not match the nut and washers which were #6. The instructions called for a 6-32 bolt.
3. The tip weight box was 5/16 inch too tall to fit in the wing. I had to saw the plywood parts down before assembly.
4. The leadout thimbles are too small for the leadout wire provided.
5. The instructions erroneously say to glue the wing fairings on over the landing gear and then remove the landing gear. The landing gear cannot be removed after the fairings are in place without removing the fairings.
6. The screws provided to mount the control horns are 1/8 inch too short. They will not contact the nylon keepers enough to screw in once placed through the flap and elevator pads.

One other suggestion to improve the kit would be to provide allen head screws instead of slotted ones. In small sizes I find them much easier to use.
Thank you very much for providing for the needs of our control line hobby.

John Fitzgerald
Fayetteville, AR

john e. holliday · « **Reply #58 on:** January 14, 2012, 09:13:55 AM »

Now you know why I stock allen head machine screws to replace what comes in some kits. The slotted head screws are mucho cheaper for the kit manufacturers to put in kits. I still wonder how we got kits builts back in the day, with the die crunching and the wood that was supplied. But, we got them built and painted and flew them. We also thought they were great at the time. Guess we are getting spoiled with the laser cutting and new control systems. Can you imagine a bicycle spoke for a pushrod?

Brett Buck · « **Reply #59 on:** January 14, 2012, 12:11:46 PM »

Quote from: john e. holliday on January 14, 2012, 09:13:55 AM

Can you imagine a bicycle spoke for a pushrod?

I don't need to imagine it, I did it! BTW, the US-built bike spokes had 2-56 threads on the end and worked well with Kwik-Links.

Brett

Jim Kraft · « **Reply #60 on:** January 14, 2012, 04:23:01 PM »

Oh Yeah! Spokes with 2-56 thread, and the original kwik links from typewriters. Are we an innovative bunch or what.

Brett Buck · « **Reply #61 on:** January 14, 2012, 10:23:24 PM »

Quote from: Jim Kraft on January 14, 2012, 04:23:01 PM

Oh Yeah! Spokes with 2-56 thread, and the original kwik links from typewriters. Are we an innovative bunch or what.

For the record, I no longer recommend either bike spokes or kwik links! Might be a little weak for your tuned-pipe 75 stunt planes. But they did have one admirable quality - they were FREE.

Brett

John Fitzgerald · « **Reply #62 on:** January 15, 2012, 04:24:07 PM »

It looks like my F-51 kit's final weight without fuel will be just under 29 ounces. I put clear coat on a few hours ago (morning of 1-15) and just weighed. I am using a uniflow clunk tank mounted on the inboard side of the fuselage. No room behind the engine for much of a tank. I researched some older threads and going by them such a tank setup should work fine. Got about a 10-foot finish on it, which is fine for my sport-plane standards. I prefer good flying to good looks.

1/16 - finished. Waiting for clear dope overcoat to cure for a few days, plus good weather before flying.

john e. holliday · « **Reply #63 on:** January 17, 2012, 07:56:36 AM »

Hope she flies as good as she looks.

John Fitzgerald · « **Reply #64 on:** January 17, 2012, 11:19:40 AM »

Quote from: john e. holliday on January 17, 2012, 07:56:36 AM

Hope she flies as good as she looks.

I hope it will at least do the round pattern maneuvers. That would be good enough for a sport flier. Actually, it doesn't look real good up close. It's a 10-foot finish. Wonder how long it really takes for Sig Lite Coat clear to become about as fuel resistant as it's going to get? Would four or five days be reasonable?

Bill Little · « **Reply #65 on:** January 17, 2012, 11:23:15 AM »

HI JOhn,

It looks great for your purposes. It should fly pretty good at that weight.

Lite Coat, give it about a week. Should be OK by the weekend.

BIG Bear
RNMM/AMM

John Fitzgerald · « **Reply #66 on:** March 10, 2012, 01:12:22 PM »

I finally flew it today. Three flights. Lap times were about 4.7 seconds on lines measuring 59'8" handle to center of fuse (57'7" eyelet to eyelet). I stunted it some on the last two flights, and it turns a good corner, but does seem to settle downward a bit in tight pullouts. Flying the TT .25 with R/C carb wired open. Wonder if it would work better with a dedicated C/L venturi if such is reasonably available?

Bill Little · « **Reply #67 on:** March 10, 2012, 01:25:51 PM »

Quote from: John Fitzgerald on March 10, 2012, 01:12:22 PM

I finally flew it today. Three flights. Lap times were about 4.7 seconds on lines measuring 59'8" handle to center of fuse (57'7" eyelet to eyelet). I stunted it some on the last two flights, and it turns a good corner, but does seem to settle downward a bit in tight pullouts. Flying the TT .25 with R/C carb wired open. Wonder if it would work better with a dedicated C/L venturi if such is reasonably available?

I suggest contacting Randy Smith for the venturi and NVA.

BIG Bear
RNMM/AMM

Author Topic: Brodak F-51 kit build thread (Read 13310 times)

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