bull51

N1EDM,

It was fairly muggy, but only about 75 degrees. I fly first thing in the am, around 830 - 900 am, if at all possible. The winds were about 10-15 mph, from the south. Upon lift off, the wings just kept tetering, like a seesaw. She just would not gain speed and i could not stop her from rocking from side to side. When i tried to turn down wind she just dropped from the sky. I almost recovered, but needed about 10 more feet to pull out.

thanks,

bull

N1EDM

My Feedback: (2)

I've had days like that too... I can appreciate what you went through.... Hope you're back flying soon.

Bob

bull51

I dont wish that type of luck on anyone, but it is somewhat comforting to know I'm not alone here. I'm ready to patch the covering back together. As soon as i patch her up, she'll be ready to go! Not sure if I'll ever be ready, but Im gonna face the music sonner or later. I think I'll go with a smaller diameter/larger pitch prop, like Mustang said. We'll see.


Thanks guys!

bull

Mustang Fever

My Feedback: (2)

Go for it, Bull.

I ordered the last of the items for mine today, taking of advantage of Tower's discount structure with two different orders.

I really liked the idea of the Saito 150, but after comparing it in detail with the OS 120 AX, I went with the 120. It's about 8 oz lighter, and offers a little more thrust, about the same speed, and the same fuel consumption as the 150, as it is a very slow turning engine. (about 9K). I'll be using a 15x10 prop, which should be good for close to 90mph and about 14# of thrust.


The only decision left to make is coloring. I can't make up my mind. The latest two candidates are shown.

bull51

Keep plugging along, Mustang. I think both those color schemes are sharp.

Well, I think my stang is ready for another flight. All back together and re-balanced. Just waiting for my new props from Tower. LHS in the area didnt carry any props longer than 12". While on the topic of props, is there a prop labeled as 16x6-8? Thats the way it reads in my manual. I took that to mean 16 inches long, by 6, 7 or 8 pitch.

bull.

Mustang Fever

My Feedback: (2)

I think they mean 6 or 8 pitch, but I have seen some wooden props labeled with a dual pitch. I'm not sure what it means.

skylarkmk1

I believe the pitch changes from 6" inside to 8" at the tip, or the other way around.

bull51

Well, I went to the field for another attempt at a flight, but it was too windy. I'll have to wait until Wednesday afternoon or Thursday morning.

bull

Mustang Fever

My Feedback: (2)

Bull: the wind has been the big block to flying here, too. I don't think we've had more than four days where it didn't blow 20-30 mph since late April.

Since I can't fly, I've been making a little progress on the Mustang every day. The tip blocks are on, and the ailerons fitted and hinged. One block is shaped and sanded. I'm going to give it a coat of thinned finishing epoxy before I shape the other one, so that it won't get dented or chipped or busted, as shaping tips requires that I put one wingtip on the table, then sit in a chair with the tip I'm working on in my lap. This thing is a lot bigger than I expected it to be.

New color scheme. I think I'm going with this one. I like the green/gray camo, the RCAF markings, and I especially like the yellow leading edges. I'm going to make them come a bit further aft, top and bottom, than the prototype, for better visibility. I want to cover the cowl and air scoop, so I ordered the fiberglass pieces from

http://www.fiberglassspecialtiesinc.com

I'll be using ultracote light gray and olive drab, along with monokote yellow and lustrekote yellow for the spinner.

Mustang Fever

My Feedback: (2)

Felt lucky last night and cut out the first flap. Came off real nice.

The OS 120AX arrived this am. That monster fits nice within the cowl, but the slimline Q muffler is too wideand would have required too much butchery, so I'm exchanging it for a macs muffler and one of the extensions, so I can mount the engine inverted with the exhaust sticking out the side.

Think of the 120 as a cheaper (by about $230) Saito 150. Same props, same rpms.

Michael211

My Feedback: (1)

Hey Bull... I realize hind-sight is 20-20, but when your plane is barely managing to stay in the air (wing tips trying to stall out on you, making it rock back and forth) one should NOT try to turn the plane! The best course of action is to keep straight and (if you have any altitude at all) put the nose slightly down and try to get it back on the ground in as few pieces as possible. You can't turn when you're barely flying.

Also try doing some high-speed taxing before your next maiden. Get a feel for it running on it's mains with the tail up and level. Take the entire runway and run it end to end, as fast as it'll go without actually taking off. It helps to get a feel for how the plane will handle when you do take off, IMO. Also helps to build up confidence levels.

Best wishes!

- Michael

bull51

Michael,

Well, you are a mind reader. I was out at the fied sunday to do just what you suggested. A few high speed runs on the mains. Then put her up! But, the wind was so bad I was afraid one of the gusts would put her in the air unexpectedly or blow her off the runway.

As for the maiden, I would have loved to keep her straight and nose down a little, but I think the trees at the end of the runway would have done just as much damage and I had no ladder to get her down if she got stuck in one. I hand no other option but to try and turn. If the wind was from the north that day, I would not have had any issues regarding trees, but, sadly winds were from the south....and we know the rest. I Thanks for the tips!


Mustang,

Looking good. I hope the winds die down in MI and NY, for both our sakes!

Michael211

My Feedback: (1)

Ok well, know when not to fly then. LOL!

I'm not a fan of gusty winds. I'd rather take my aircraft back home in 1 piece than risk flying in weather conditions that are ugly. It's just not worth it, IMO. Especially for a maiden flight... I won't maiden an aircraft until I get ideal weather conditions!

Sorry your flying field has such obstacles at the end.... my club's field is a full 50 acres of nothing but grass. There is a treeline but it's wayyyy away from the end of our runway... plenty of room to set one down (in the grass) without turning if necessary.

So how's the rebuild going? And did you take any pics of the plane after the maiden to share? [:-]

- Michael

bull51

Well, took her up for a second flight today. It went very well......at first. Takeoff was smooth as can be. She kept nosing up though. Had to put in a lot of down trim. Made a couple of passes, then was banking right for another pass when she rolled completely over and fell from the sky....again. I'm at a loss here. Must have messed something up during the build. She's not repairable this time. I have video clip of part of the flight, but cant figure out how to upload it. Keep getting error message.......mpeg flie not supported.

bull

Mustang Fever

My Feedback: (2)

That's bad news, Bull. I'm beginning to think maybe you have some kind of radio problem.

bull51

I dont think this is a radio problem. I'm using 2.4 ghz spread spectrum. Not to mention, after she rolled she was reponding to my inputs, I just could not recover in time. The good news, once again, is that my engine and radio gear all survived. I've alwas sadi that's my main concern and the most $$$$$. Wish I could post the video here.

Redwulf__34

Hi Ya Bull,
She wasn't tail heavy was she? Also, is this your first Warbird? I'm wondering what you've been flying up until now. Warbirds will fly a bit differently than than sport or aerobatic planes. I remember learning to fly my first Warbird, it was a Mustang too. She always wanted to dip that wing if airspeed was low. Airspeed is critical especially in turns and they don't like to bank very steep when slow.

If she was a little tail heavy and your speed was low and the bank too steep that would cause a reaction like you described. Don't give up. Are there some guys familiar with Warbirds there helping you?

With your video you may try converting it with Movie Maker. I'd like to see it too. It sounds like the file format is not compatable with where your trying to upload it. Try opening the video with Movie Maker and then saving it as wmv file. That may work.

Sean

Mustang Fever

My Feedback: (2)

Bull:

A few of the Mustangs I crashed acted the way you described. One, in particular, would kind of start to drag its butt as the speed was reduced. That turned out to be a tail heavy condition. I have not yet taken the TopFlite drawings and figured my own mean aero chord and C of G. It's possible TF goofed. It wouldn't be the first time. Don't let this experience turn you off Stangs. I had a similar experience with a Laddie Mikulasko Arrow in 2006, when it started porpoising and augured in on its maiden. It was a CG error on the designer's part. Happens all the time. I built another one recently and have flown it quite well, since figuring out where the CG should really be.

FLAPS

I have been putting these off for at least two weeks, finding excuses to work on something else, because the whole process scared me. We're putting a tapered radius on a tapered surface, and we get one chance to do it right. Trying to make a set of replacement flaps (after ruining the originals) to accurately fit the wing would be very difficult, I think.

Pic 1: I used one of those drafting "circle" tools to draw the flap radius on each end. Then I used a razor plane to roughly shape only the ends, and slim the flap down between the ends. Then I used the "shoe shine" sandpaper technique to get the ends nicely rounded, and gradually moved away from the ends and shaped the center.

Pic 2: I used a belt sander to taper a piece of dowel rod that was roughly the diameter of the big end of the flaps. It's not quite half the length of the flap opening. The small end matches the small end of the flaps. By moving it inboard and outboard and sanding gradually, I was able to get the flap pocket the correct shape and taper.

Pic 3: Hard to see the rib tips, but the curvature is there.

4&5: Seems to fit well, lines up with the aileron and the wing root when retracted, and goes up and down very smoothly. Next I'll have to see how it does with the hinges. Yipes[X(]

Michael211

My Feedback: (1)

Ouchie Bull! Sorry to hear that.

That behavior really sounds like the CG was too far back. In straight ahead flight, it makes the plane want to pitch up and climb without any elevator input.

Don't give up... but I'd suggest getting an ARF Mustang this time and trying it instead of taking months to build one from a kit. At least with an ARF you won't have so much time invested in the thing, and only a little more money than with a kit.

For inspiration go see this thread about a Kyosho ARF that the owner BARF'ed and how it turned out: [link=http://www.rcuniverse.com/forum/fb.asp?m=7743924]Kyosho BARF Mustang[/link]

Good luck and hang in there!

- Michael

Mustang Fever

My Feedback: (2)

For only $145, that might be a good way to go.

It's about a 55" wingspan, 40-46 size bird. Available through many LHS or directly from the Kyosho web:

http://www.kyoshoamerica.com/airplan...part_num=11823

Redwulf__34

Try this out. [link=http://www.geistware.com/rcmodeling/cg_calc.htm#cg]CG Calculator[/link] I'd be curious as how this matches with what the Top Flite plans say the CG is supposed to be.

Sean

bull51

Thanks guys..


Well after the frist flight went bad, I kept her a little nose heavy, or so I thought. Followed Top-flite's spect to the letter......gear down....ready to fly minus fuel. I'm already looking for a replacement, maybe the 1/7 top flite P-51 ARF. Heck, I've got all the gear, plus spare parts....flaps, elevators....ailerons...pilot...you name it, I've got it, lol.

I put the video on youtube. here's the link.



http://youtube.com/watch?v=kO5H3kOA_z4

Mustang Fever

My Feedback: (2)

Sean, I wouldn't know where to begin plugging in numbers. Maybe one of the other guys?

Here's what I did, measuring along the TE and both LEs to the aircraft centerline:

RC1: the chord at the "break" = 15.375"
RC2: the chord at the actual "root" = 17.375"

TC: 7.5"

The short, root section of the wing is roughly 1/3 of the span, so I arrived at an average root chord like this:
RC1+RC1+RC2= RCX; RCX/3= average root chord.

I came up with 16" for the average root chord. Adding this to the TC of 7.5 and dividing by two yields an MAC of 11.75".

Here it all is, plotted on the LH wing panel drawing:

The MAC of 11.75" lies along the inboard edge of Rib W6.
25% of 11.75" = 2.93"
30% of 11.75" = 3.50"

I plotted these CGs spanwise so they would intersect with rib W4, where TopFlite wants the CG to be measured.

Top Flites CG recommendation is so close to 30% that the difference is insignificant.

The only Mustang I ever had that flew OK at 30% had an oversize stab that I drew myself. It was close to 30% of the wing area, if memory serves. All the other scale outline ones (four) went out of control and crashed as soon as I attempted to slow down for approach to landing. This tendency is exacerbated as the fuel burns off, making them extremely treacherous at low speeds. The Top Flite 1/7 P-51 has a stab area that is approximately 136 square inches. The stated wing area is 734 square inches. That's an 18% stab. Better than my Hangar 9 Camel, but not by much. 25% would probably work well for this model.

This business of aircraft companies recommending maiden flights at 30% CG is just plain dumb. All it takes is a very minor mistake on the CG machine with a model this small and the builder will be on the wrong side of it.

I'm sorry I didn't do this earlier, Bull, I guess I'm guilty of trusting Top Flite. It seems they are no more trustworthy than any of the others, including Hangar 9.

bull51

My goodness, Mustang. Not sure what all that means, other than the CG that the plans call for is wrong? Makes the plane tail heavy? You would think, with the popularity and age of this kit, these issues would have been addresses and corrected long ago. Did you check out the video? Its not all that long and my buddy stopped taping just before she rolled.


Redwulf,

Yes I think, based on what I saw, she was a bit tail heavy, but not sure how that could be. Marked the CG where the plans say, I balanced her a bit nose heavy, then with a full tank, I should not have experienced any tail heavy characteristics that early in the flight, i think. I was an awesome expeirence to fly her, even for a short time. cant wait to get another (ARF that is).



Let me know what you guys thing of the flight. I know its not much, but she looked good while she was up there.

bull

Mustang Fever

My Feedback: (2)

Bull:

That's my conclusion. Like I referred to, it happens a lot.

I looked at the video, but really couldn't see much other than the constant nose up attitude.