Mustang Fever

My Feedback: (2)

Thanks, Sean.

A bit more grinding in the forward saddle area, and the wing fit pretty good.

Here's the planned layout for the machinery- I'm going to use the factory servo tray per the plans for rudder, elevator and throttle. After looking at the brazed up elevator control horn, I decided I can trust it, so I'll use a single HS 475 servo for the elevator.

I'm going to locate the retract valve and servo cross ways in the front of the tray, and make a tray for the tailwheel steering servo and retract cylinder to go behind the main tray. The air tank will fit in the factory cutouts.

If necessary, I could put the t/w steering servo forward of the main tray, and locate the air tank inside the belly scoop. Anyone have any thoughts on this, as far as balance is concerned? The 120 AX 2 stroke is about the same weight as a 120 4 stroke. Gords: where did your various servos end up, and how did the balance come out?

Redwulf__34

Looking good Bob,
Think of this kit as you would if you were scratch building and you'll be ok. I can't waite to see it finished too. I'm enjoying watching the build. I've had so many different plans pop up here lately I'm starting to "waffle" on what to build next!!! I'll enjoy watching yours for now!

Sean

gords

I have the same type of setup as you show. including the way you have the tail retract cylinder mounted. I also have a JMS door sequencer in there. I have a saito 1.5 on the front and needed 2 ounces of lead in the rudder to balance it. I used a fish scale to weigh it, so the numbers are exactly precise, but it came out between 12 and 13 lbs. Also what size of airtank do you have? Mine was too small to fit the cutouts for it and then I ordered a larger one and it was too big so i'm not sure what size it is that fits right like you have shown.

Mustang Fever

My Feedback: (2)

Thanks, Gords. I went ahead last night and installed the tailwheel steering servo ahead of the main tray, up high so I could run the pull/pull cabling above the three main servos. That bit of extra weight up near the nose should help a bit. The bottom of the servo is actually up under the rounded part of the fuse forward of the canopy, where there's plenty of room for it.

My air tank is the one that came with an old retract system I never used, B&D I think, and it fits nicely into the cut outs. I'm going to push it back into the scoop area a bit so that the servo tray area is open.

gords

I used the rudder servo to drive the pull-pull set-up. I'll try to take some pics and post them. You can save a servo that way. There are some pics of this type of set-up earlier in the forum as well.

Mustang Fever

My Feedback: (2)

I dunno, Gords.

The first retractable bird I built was an F-4, and I ended up using a separate steering servo because of space limitations. It work so well I automatically went that route on the Mustang. The main thing was being able to get the joker tracking straight down the runway with rudder trim, then bring it back and center the rudder mechanically using the clevis adjustments.

Mustang Fever

My Feedback: (2)

Made a little more progress today- the air system is just about complete.

If I had thought about it a bit more, I would have flipped all the aft formers around 180 degrees, so that I could put the rudder pushrod on the right, rather then the left, as the inverted engine will require the throttle servo to be on the left. Too late. Had to put the throttle servo forward, along with the tailwheel steer.

Redwulf__34

Looking good bob! One question. What's the weather like up there? You seem like your doing more building than flying! Should be flying now.

I had the DUS out last night. Still fighting with the engine. I think I got a bad fuel tank now. I pulled the hatch to take a look at something and saw some moisture around the tank lines.

Keep up the nice work. I can't wait to see her come together.

sean

Mustang Fever

My Feedback: (2)

Sean:

This has been the most unbelievable summer. The wind has been blowing 20-30 mph almost everyday since early May. Most of my flying is done down at the lake, early in the morning before the wind gets going. I've been flying my Mikulasko Arrow more than anything.

Mustang Fever

My Feedback: (2)

Big day today! First time she sits on her wheels.

I fit the wing a little differently than specified in the book, and maybe different from some other folks:

1. I centerline the wing after it is completely built by measuring from tip to tip across the spar, and dividing in two. That centerline gets marked at the TE and LE.
2. I centerline the two bulkheads at the ends of the wing saddle, and mark them.
3. I fit the wing such that the centerlines match, TE and LE. This insures an equal amount of wing hanging out each side of the fuse. It also insures, if one has been careful during fuse and wing construction, that no adjustments will be necessary to obtain equal measurements from the tips to the tail.
4. Once the wing has been fitted down into the saddle, I clamped it place and drilled the holes for the nylon bolts in front. Then removed the wing, and did all the tapping and clearance drilling, etc.
5. Wing is now replaced, clamped at the TE and bolted at the LE. C/L marks aligned.
6. I cut out part of the center of F-9 at the bottom, to make room for a drill motor and a long 1/4" bit. I used that to drill right through the F-8 dowel holes and into the back of the wing where the dowels are installed in that complex belly scoop structure. This was necessary because none of the holes lined up, and my scoop structure had a 1/8" error on one side due to a clamp popping off while the glue was setting and I was not around to notice it.
7. Last step: cut dowels to length, round off the ends, and install from the rear into the pockets. Thick CA in place within the scoop structure. Remove wing. Reinstall wing. Lower landing gear.

All that time engineering the main landing gear really paid off: note how far ahead of the CG the axles are. Should help with the noseover tendencies of these airplanes.

Mustang Fever

My Feedback: (2)

Here's the chin block and the radiator housing blocks all pre-shaped, just outside the line traced from the various former patterns so I won't have so much to do later.

Needed a break from gluing, carving and sanding, so spent some time making a test stand for the 120 AX. This engine will be inverted, with a painted aluminum spinner that I do not want to use a starter on, so my main interest was in determining how well this engine hand starts while inverted. A little fiddling with priming and throttle setting, and she pops right off and goes without very much flipping at all. I'm using an old US Army issue leather glove with the wool liner to keep from getting sliced.

I'm getting 8000 rpm on a 15x10 K prop after thirty oz of a 15% fuel that I added a lot of castor oil to. Oil content is probably 25% or higher, as you can see by the exhaust. I'm going to put one more tank of this stuff through it, allowing it to completely cool down after each run, and then switch to a 10% fuel to see how she peaks and idles. She won't run super rich due to being inverted (and maybe the extra oil), I think, so I may try an A-5 plug down the line. (The factory A-8 is in there, now.)

Mustang Fever

My Feedback: (2)

Ran the 120 up again, this time with a 14x12. It will peak at almost 9000 with that prop. A little faster and with a bit less thrust than I'd like, although 108 mph at 9500 would be really cool. I'm going to pick up an APC 15x10. It should have less loading than that 15x10 MAS "K" series that I tried, and might be just right. This engine will idle reliably at under 1700 rpm with the 14x12, and transitions smoothly back to full throttle after a minute of that. I am very impressed with it.

I decided awhile ago to enlarge the tail surfaces a bit. As designed, the stab is not quite 17% of the wing area, and I'd like it to be close to 20% for better stability at low speeds. I glued a couple pieces of 1/2" wide balsa stock to the existing TE and shaped them to match, then blew the stab tip drawing up 117% to get a matching tip curvature, and made new ones.

The exhaust stacks that come in the kit are kind of sickening to look at, so I ordered the ones for the 1/7 scale ARF. They are identical in size and a bargain at $11. I've had the ARF cockpit kit on order all summer, too.

xcanadamanx

those are some sweet exhausts![X(]

Mustang Fever

My Feedback: (2)

Big day today- the stab and fin got epoxied on, and the control surfaces fitted. Still have some sanding and shaping to do, but the tailfeathers are essentially done.

Mustang Fever

My Feedback: (2)

Another big day- installed F1A and the various pieces that go into mounting the engine. Weight now is 10 pounds. This is with most of the servos in, but no battery, and of course the top of the fuse, cowl, airscoop, etc.

Mustang Fever

My Feedback: (2)

Couple more pics. I made a 7/8" thick spacer out of 3/4" maple and 1/8" ply to get the OS aluminum mount the correct distance from F1A.

I must say that as far as the critical things- incidences and alignments, this kit is hard to beat. It was very easy to get everything correctly lined up.

Redwulf__34

Look very good bob! I cant waite to see the top go on!!

Mustang Fever

My Feedback: (2)

Sean:

Gotta go to St. Louis for the week, so no more Mustang progress for awhile.

I will get to fly my Phantom, though.

Later.

Redwulf__34

I have no experience at all with Gas engines. I would love to move into gas for a number of reasons but I don't have room to store nor transport larger models. 1/7 about the size I need to stay in.

Would this [link=http://www.hi-techobbies.com/index.php?main_page=product_info&products_id=365&zenid=feo8nll73evlb3ebcqqnk8j2c3]17CC[/link] gas be too much for this bird? How does the Gas sizes convert to Glow?

Sean

Mustang Fever

My Feedback: (2)

Yeah, me too.

I looked at putting the Evolution 26GX in this bird, but it weighs 33 oz and that's without a muffler or the ignition battery. In contrast, the max 4 stroke recommended for this airplane (an OS 120) weighs 33 oz total. By going to a 120AX, I get a bit more performance than what the 4 stroke offers, at less than 23 oz w/o muffler. I think the Macs muffler only weighs about 4 or 5 oz, so I'm still under 30. I don't want to add weight to the tail if I can avoid it.

Mustang Fever

My Feedback: (2)

Sean- you mentioned getting the top on the 7th of this month, and here I am just digging out from under a pile of balsa dust on the 26th.

I used the sectional drawings in the plans to make guides for shaping and sanding, and it has come out reasonably well.

I think the cowl is next. After I vacuum up the mess in the shop so I have room to make another one.

Redwulf__34

Looking good! Are you building the B or C model? Or does the dorsal fin go on later?

Sean

XxOoCoBrAoOxX

Hey guys, I had the engine fired up today (3w60) and every time I turn on the smoke system(Flick the switch to on), the smoke shows up after like 10 seconds of waiting and then some smoke comes and again. It seems as if the smoke only pops up every 10 second periods for only about 5 secs and goes back to the same routine. Pretty weird.. Any suggestions/help?


Thanks!

-Adisn

planebuilder66

My Feedback: (8)

Smoke pump not working right or the pre-heating coil in the muffler is not getting hot enough.

Mustang Fever

My Feedback: (2)

Sean: She'll be a D. I might do the dorsal as the next step. A bit easier than tackling the cowl. Here's the color scheme I'll be using: