martys40s

My Feedback: (213)

Hi Ron, Please contact me. Marty

meddad

Hey all, I am ne wto this forum, as well as this being my very FIRST kit! I am working many crazy hours at work, and have an hour or two every other day or so to work on the tp[ flight .60 P-51. I just started with the stab, and I noted that the leading edge is supposed to be cut 1/4 inch longer than the plans. because of this, I caonnot put the stabs together on the plan at the same time. Any tips?

James (AKA 911)

bull51

what I did was trim the leading edge (mating side) to the angle on the plans, then I cut it to the suggested length, then I lined it up on the plans. Let the outside edge hang over until the last rib is in place. The trailing edge is square, so I lined the mating edge up on the plans and let the outside edge hang ove a bit. Hope that helps.



As for the maiden, Friday a nasty day here in NY, so the maiden will have to wait.

Mustang Fever

My Feedback: (2)

I must have forgotten to click the "email notification" box the last time I posted here. Didn't realize the thread was still going.

Sean, your Mustang is pretty. I think I'm getting motivated again to restart on mine.

I took the wing down and looked it over last night, and it's still a nice, straight, rigid structure with probably the strongest retract mounts in history. Just a touch weighty, but I can live with that.

Here I go.

Mustang Fever

My Feedback: (2)

First time since Jan 18 that I've done anything to this model. Back then, I filled in the big holes in the bottom of the wing that the gear doors would have covered, had I decided to continue with that. She has "AT-6" wheel wells, now. I also put in some paper tubes for routing of the aileron servo leads. I'm using the HiTec HS-125 MG wing servos, the flat ones that are technically micros, although they have 41 oz/in at 4.8VDC. For Flaps, I'm using one Futaba S-3004 and one HiTec HS 325, so I can mount them "horns out" on both sides, instead of asymmetrically.

I ordered about $200 worth of stuff from Tower this AM, flap servos, aileron servos, Rx, switch, glass cloth and some glue.

I have this (probably unrealistic) goal of bullet proof landing gear, as I have no desire to ever cut into the wing for repairs, so I:

1.) Made little balsa triangle shaped "dams" and located them so that a mixture of epoxy and milled fiberglass won't run where it don't belong.
2.) Started filleting the inside corners of the gear rails and ribs with the mixture. The left side "down" pix are shown. Gravity helps with this kind of work.

Redwulf__34

Glad to see you back at it Bob!!! I'm on my way to the field right now to get some stick time on someone elses plane! I didnt get the engine running and I don't have a muffler or mount for my Supre Tigre so I'm back on hold with the maiden.

Anyway, with all the gear talk here I thought you all would like these detail pictures of [link=http://www.aviation-top-pics.com/details-P-51D.htm]Damn Yankee[/link] there are some real good wheel shots.

Here is also a poor quality [link=http://people.aapt.net.au/gjmustang/video/lg.mpg]video link[/link] of some gear in action.

off the the field now! Very hot and a little breezy here.

Sean

Mustang Fever

My Feedback: (2)

Have a good one, Sean. We've just had another in what seems like 90 days straight of 25mph+ winds. The recent rainstorms here have probably flooded our field. I'm afraid to go down and look.

Mustang Fever

My Feedback: (2)

Here's what I'm doing for the ailerons, as I don't care for bellcranks and multiple pushrods.

The 1/8 lite ply "hole liner" goes inside the wing in the bay where the bellcrank would have lived. A 1/16 ply servo plate gets screwed to it. The small basswood mounting blocks for the Hitec 125 thin wing servo have not yet been glued in place, and the servo arm slot has not yet been cut.

It's probably the memories of all those control line planes I cracked up when I was kid.

jeffk464

Good decision, the bellcrank set up scared the crap out of me. My set up with two aileron servos works great and gives me a lot more confidence.

xcanadamanx

Hey guys i was wondering if someone could measure the exhaust manifold for me. i need the length of it. BTW reading through this whole thread was very informative. Thanks a lot.

Live Wire

The one I have is 7" long . Came with the kit.
Larry

xcanadamanx

Thanks Live Wire

Mustang Fever

My Feedback: (2)

I decided to finish the aileron and flap servo installations before installing the last of the upper sheeting. More room to work, that way, and it's easier to see the pitfalls. One major one is the fact that TopFlite evidently ignored the swept trailing edge, and engineered the flap servo and aileron pushrod installations with a healthy angle between the pushrods and the control horns. I have been building for six years, and it took me almost that long to get reasonably good at making control systems that move freely with no binding. There is just enough room between the ribs in the servo bays to "crank" the servos around enough to get a nice 90 degrees between the respective horns.

Bad move, TF.

I also went with one HiTec flap servo, and one Futaba, so they rotate opposite one another on a Y cord, and eliminate the assymetrical mounting that would be necessary otherwise. I find that the HS 325 and the S 3004 are a very good match, travel wise, and the 325 has a more or less infinitely variable length control horn that can be nicely matched in length to the Futaba's. I wish Futaba would take a lesson from HiTec on servo mounting, tho. Only one word describes Futaba's: sucks [:'(]

Mustang Fever

My Feedback: (2)

I cheated today.

I bought the plastic landing gear doors, cockpit kit and exhaust manifolds for the ARF.

Redwulf__34

Ah, whatever it takes to get it up in the air Bob!!! I've got the engine all re-mounted on my DUS and ready to go. I'm going to run the engine tomorrow evening then she'll be off to the field. After that I'll maybe start working my Pony over and see if she will fly.

I got all stuck on a muffler for mine. I mounted a Supre Tigre .61 in it and never found a muffler to get out it.

Sean

Mustang Fever

My Feedback: (2)

Sean: How did it go? We had another normal day here, 25mph winds all day, so no flying.

Got the last of the sheeting on the 51, and did all of the rough sanding. This has to be one of the most rigid structures I've ever seen (out of balsa, anyway). Topflite did a nice job designing this wing.

Tomorrow I'll cut the flaps out and start finishing them. Probably take most of a week. After that, ailerons and wing tips, and then it will be tail feather and fuse time.

After changing my mind about engines and color schemes at least 50 times in the last year and a half since I bought the kit, I've decided on Paul I (the EAA example in the Oshkosh museum) and a Saito 150, inverted, using the slimline wraparound inverted pitts muffler, and either a 16x8 or 15x10 prop.

And I'm going to acid etch and paint the 4" Tru Turn spinner with yellow Lustrekote, to match the rest of the nose. Hand starts only for this one.

bull51

Hey guys,

Well, here's the maiden fight report..and it's not good. Crash and burn. She got in the air quick, but was uncontrollable. I tried to bring her around and pick up some air speed, but the wind got her and slowed forward movement, and, I think caused a tip stall which sent her to the ground. I think she was a little tail heavy, but dont know why. I balanced her where the plans said. Or, maybe I wasnt getting enough rpm's, mixture too lean. I'm really at a loss here. On a lighter not, it looks like the engine and radio gear survived the impact. I'm going to dig a grave now so I can lay her to rest.

bull

Mustang Fever

My Feedback: (2)

Sorry to hear that, Bull. Do you remember the following:
1. Total weight, dry.
2. Engine
3. prop diameter and pitch.

Also, what kind of wind did you have that day?

bull51

Thanks, Mustang,

total weight was 11lbs 12oz. dry. The engine was an os 120 pumper, 16x8 prop. Winds were from the south, moderate. I could not gain any air speed. She was uncontrollable, as mentioned earlier.

Boy, this year has really shattered my confidence. Never had a season like this before. Too many crashes.

bull

Mustang Fever

My Feedback: (2)

Well, Bull, we all want you to get your confidence back. Mustangs are very demanding. I've cracked up at least a half a dozen of them. The more scale they are, the more treacherous they are. They have only one friend: SPEED. Let's do the math:

Wing area: 734 square inches, 5.097 square feet.
Weight: 11 pounds (176 oz) + (12oz)= 188 oz.

188/5.097= 36 oz per square foot.

The chart below will give you the stall (minimum flying) speed at various altitudes. At that wing loading, I'm estimating about 26mph at sea level, which Newburgh should be close to.

OS does not recommend a 16x8 for that engine. It's possible she was really lugging down on you. Were you able to tach before flight?

Some speed thrust combinations for that engine:
14x9: 81mph, 10.5# @ 9500rpm. Indicated HP is 2.1
15x8: 68mph, 12.3# @ 9000rpm. HP 2.1
16x6: 52mph, 16#, @ 9100rpm. HP 2.1

16x6 is the biggest prop recommended, and you can see that the speed generated is marginal for a 26 mph stalling speed. Safe and comfortable flying requires a top end of at least three times stalling speed, preferably four times or more. This is because we tend to make such rapid turns with models in order to keep them in sight. A rapid turn from into the wind to down wind without a very large ground speed margin can cancel the airspeed enough to drop the airplane from the sky. (Experience speaking, here.) For example, if you have a 25 mph headwind on TO, the airplane might lift off and be controllable at a groundspeed of 15 mph, for a total airspeed of 40mph. During a quick turn downwind, tho, the airspeed can drop as low as 25-15=10mph, and the aircraft will stall and crash.

Bottom line: on a maiden, go for the speed and sacrifice a little thrust. I would have picked the 14x9.

You can do it. Just pick up and go build another one. Nearly everyone I destroyed was due to letting it go too slow under various conditions.

bull51

Mustang,

Thanks for all the info. OS manual says 16x6-8. I took that to mean 16 daimeter x pitch between 6 and 8. I opted for the 16x8. not sure why. I did not tach before flight. but thank God my os still runs and she tachs out at over 12000 rpm with that prop. I just need to get back on the horse, like you said.

Thanks again.

bull51

Well, I'm not on the horse yet, but construction is under way. That's right. My stang is being pieced back to gether as I type. It's not going to be easy, nor will she be a pretty as before, but she'll still be my Big Beautifeul Doll.

The fire wall was torn clean off, the servo tray was craked in half, all of the pusrods were bent almost 90 degrees. The cowl was shattered in too many pieces to recover. We'll see what happens. With any luck she'll be back in tha air soon. Oh and of cousre, the landing gear was ripped off.

By the way, engine radio and servos, all appear to be in fine working order.

Redwulf__34

At a boy Bull! Climb back on that "Pony"
If she doesn't look great once you piece her back together at least you can learn a few things flying it, then maybe you can re-build totally at a later point.

Sean

bull51

Redwulf,

Thanks. You must have been reading my mind. Im gonna put her back in the air and fly her wings off. Just patching the fuse up now. all structural repairs on the fuse are complete. Then I can start on the landing gear.

N1EDM

My Feedback: (2)

You say that you lost power.... was it a particularly hot day? I had a day like that a few weeks ago and two of us had the same issue... the plane seemed to lose power after takeoff. I was lucky and was able to glide straight in to some tall grass with no damage. My friend stalled his FW-190 (the power loss happened on climb-out at a most inconvenient time). He really clobbered the nose section but it's back together now.

My question is whether you were flying on a very hot, muggy day. That's all the Horst and I could come up with for the reasons that our planes lost power like that.

Just m $.02

Bob