sabre1205

Man I hate when that happens. At least it was'nt so quick that you could'nt figure out what went wrong
Again sorry about your loss.

Where can we send flowers

EscapeFlyer

My Feedback: (1)

I've read a lot of problems flying this mustang. Is this bird that tricky, or just bad luck? I have a B version I would like to build, but wondering if I should go with something different now.

Here is the direction I was planning to go:

rotccapt

looks like a cool scheme should be fun i finally got my carb parts and ignition parts i have been waiting for. i will be working on getting the engine finished and i am hoping for a maiden in the next couple weeks

scratchbuilder46

Bipes, I also have a "B" model and it flies just fine. Just make sure the CG is correct. Balance it out about 1/8" forward of the CG called for on the plans and it flies great. I have a video of mine on youtube under "corona rc club" you can judge for yourself as to how it goes. My speed with an OS .91 four stroker is about 65mph, which is about scale for this models size. If I take the tanks off it can gain more speed. That will be an option when I can set it up with a 7 channel radio(future purchase). I am working on a "D" model right now for our club pres. Take a look at mine even the first flights, getting the retracts to work right, the belly landing did nothing but scrape the engine head and make me repaint the tanks. Nothing else. The better flight was with the P-39, which I also built, and was given the mustang to do it. Go for it!

FallDownGoBoom

My Feedback: (1)

Ditto what ScratchBuilder says. The Mustang flies fine, unless you max out the scale/retract details and fly a heavy aircraft with a small engine. Mine didn't have retracts, used a Magnum 91 4s for power, and it took off in about 150 feet, climbed out normally, looped and rolled fine, and was even spectacular going in [:'(]. But it was a pure radio problem, and had nothing to do with flight characteristics.

Build away... the Berlin Express theme looks great.

Mustang Fever

My Feedback: (2)

George:

The only personal experience I have with 2.4 is the Futaba 6EX systems, and I've found them to be bullet proof. The Spektrum stories are from other guys, many of which are posted on a thread in the jet section. A bunch of fellows in the UK did some very intensive testing of both systems, the conclusion being that the Futaba can't be messed up, and that the Spektrum has some unknowns.

gmohr

Bipes,

I found that in the short time I got to spend with her, my Mustang was a very honest and easy to fly airplane. In fact it was much more "in my head" than it deserves. Mine was 10 3/4 lbs, and it would land at a very slow pace, with no tendency to snap roll. I think keeping it light(ish) and building a dead straight wing is the key to this. Look through this thread to see various techniques to getting the wing warp-free and containing the right amount of washout. Naturally, I would suggest my approach but others work also.

Second, if I were doing it again, I'd go with a 95AX or similar. I felt that the 120AX was really just overkill, and a few less ounces in the nose (and offsetting tail weight) would have made it even better.

Third, build a baffle in the cowl for cooling. Don't skip this, its just not optional IMO.

You'll love this plane!

gmohr

On the topic of my control problem, I've posted in this site and rcgroups in the radio forums about my event. Most opinions are that the servo would *not* have been neutralized by airflow/g's in my situation, and that allows for a power failure of some kind (battery/switch/etc) as the root cause, and not exclusively the receiver. The only thing I know for sure is that nothing came unhooked or unmounted, i'd bet the farm on that. Beyond that, I just don't know.

Regards,
George

EscapeFlyer

My Feedback: (1)

Thank you for the imput. Actually, I was going to mount my ST 90 out the side rather than inverted and in the cowl. My thinking is that as nice as I plan to build it, I know there will be scale sacrifices I need to make in order for it to be reliable. This would eliminate cooling issues. Plus I like looking at the engine as well. (I know- I'm wierd) Some people can really build around these potential hazards, but I am not one of them. At least not in this small of a scale aircraft- yet.

Don't get me wrong, I really admire the work others have shown here. I simply don't have that kind of scale building experience. I still think I can pull off a nice looking P-51B though.

So it will be primarily stock with some small changes that I have read in this thread, as well as in the PM's that I have shared with others.

The Berlin Express ought to be pretty cool though.

Brian

Riddle4U

George, I also weigh-in on your loss...beautiful model!! Really a bummer. No one could say for sure what caused your disaster (hope you find remains sometime). I will say I have driven it home to my younger brother that voltage readings for receiver batteries are all but meaningless without cycling and reading capacity! I explained this to him, but it didn't sink in until he lost reception with one of his planes. He had just field charged it and checked voltage with an ESV (expanded scale voltmeter). It read at the top; all in the green for sure. He flew for 2 1/2 minutes and he lost input while doing a slow fly-by. The plane decended and hit rising earth 300 yards away while level and slowed (no control throughout). He was lucky! No damage except prop and bent nosegear. When I got home, I charged then cycled his battery....low and behold (no surprise to me), his cycled battery capacity was about 100 MAH (for a 500MAH batt)! Lesson: a "fully charged" battery means nothing if you don't know the cycled capacity in MAH. His voltage declined to near nothing in TWO MINUTES; battery was bad. Now he has invested in a cycler from Sirius Electronics (I use the same technology in my ACE cycler). This will measure your true battery health in terms of capacity.

Who knows if that was involved in your problem, but a large percentage of "radio failure" is battery related...that simple. I cycle once a month during the season, and charge between most flights at the field (better safe than sorry). There is a myriad of things that can impinge on radio performance, but I have found many of my post mortems to be due to battery condition/quality or other vibration oriented causes (metal to metal e.t.c.). I hope you'll get another TF Stang in the air in the not so distant future!

Edit: misspelled Sirius Electronics originally, good equipment!

rotccapt

have fun with your build. i am so close to d-day that i can almost smell the burnt gas (oh wait that is just the residue on my hands from tuning the engine lol) i had to re due my tail wheel retract push rod because i was not getting it to lock down and the weight of the plane would collapse the wheel. now that i have that problem fixed all that i have to do is build the baffles in the cowl, attach the canopy, and finish tweaking the engine. i am getting 7500 rpm from my gasoline converted saito 125 spinning an apc 16x7 prop. i also retro fitted the engine with a walbro carb. with this combo i am getting an impressive idle of 1800 rpm. if the weather behaves i am hoping for a maiden some time in the next week or so. whish me luck

Riddle4U

Oh yes, I should remind everyone to not bypass a good field range check with a flying buddy. Take the model at a distance and do a control check at various rpm's. This can tell you a lot, and if there are severe problems they are best found on the ground. It is worth the patience considering how much time we spend building!

rotccapt

here are some pics of her assembled and almost ready to fly final wet weight is 11 lbs 9 oz.

CGAV8R

My Feedback: (2)

Looks great ROTCCAPT. I love how you converted that Saito. I hope you get some video of your maiden for us. Good luck.
Aaron D.

Riddle4U

Gmohr...did you cycle your batteries? What was the last cycled capacity? Most seem not to respond to my last post at their own peril. Keep flying and crashing models that you all have spent hundreds of hours on...folks! The number one cause of radio failure is batteries. Period. Who is listening?

Mustang Fever

My Feedback: (2)

Riddle's post reminds me of something I take for granted- an accurate voltmeter. There aren't many of them out there. I have an old one from my working days, and because of it, have had no need for cycling. It's very apparent when a battery has reached the end of it's useful life, as the charged voltage won't get up to that last 0.3 or 0.4V or so. (I think I have only two birds that still have NiCads in them, tho, I've swtiched to NiMh on everything else.)

I can also tell you this: a Futaba FAAST will tolerate low voltage down to the point where the servos will barely move at all. It's happened to me twice, once when I couldn't shut down the engine on a small, hand launched airplane (with a small battery) and had to fly around till it ran out of fuel, and once when my pal didn't charge the NiCad in his trainer. They both just got "mushy", there was never any loss of control.

Riddle4U

Hi Bob! I guess what I was emphasizing specifically is not the voltage. That is just the problem! People think a proper voltage reading means they're good. It does NOT mean that. Cycling batteries means you purchase equipment that may cost as much as your entire airborn radio system...or even just fifty or seventy bucks; but It measures MAH. Capacity. Not voltage. Many know this, and to you all..you can ignore all this. If you don't know this you need to learn before you kill your dream plane and leave the hobby out of frustration (don't laugh guys, this happens). I have measured non-nicads and found them to measure full voltage after charge also, only to measure them on a cycler and they are almost fried! This speech has been given countless times and through generations of R/C modelers. Some do listen...mostly after they ruin a perfectly good plane! Everyone wants to think HEY! its the connectors maybe! or the switch! the Tx! the Rx! Anything but the batteries...why.......because they checked the voltage carefully and it was good! Wrong! Your battery was bad! Look into buying a system that measures capacity. Nicads are fine for airborne systems BTW, just require maintenance like everything else. What I am talking about is valid regardless of battery chemistry however. I hope not to encourage discussion on battery types, I am sure that is found on RCU elsewhere. Sorry if I belabored the point, perhaps it will save someone some grief?

scratchbuilder46

I will add my two cents to the discussion about batteries. I too have ditched the nicads and have gone to nimh cells. They hold a charge longer and take a fast charge better. I do not fast charge mine, but I will cycle them about every 6 mos. to keep them in top condition. I would recommend a digital variable load voltmeter be a part of your flight gear. This will put a 1/2 to 2 amp load to your pack and give you the voltage of your flight pack under load. If I had had a meter, I would have saved a great TF AT-6 that was one of my favorites. 2 mins. in the flight, it did the locked up death spiral from 400 ft. beyond rekitting! The first thing I did was order one and use it at the field every time. The battery is checked before the wing goes on, every time. A cheap simple battery checker that may save your bird.

gmohr

The battery was an A123 LiFe pack. I did cycle it, and it had over 900mah usable capacity. Further, I recharged it just prior to that flight, and it read 7.2v just before the flight (the proper voltage for a fully charged A123).

Regards,
George

Riddle4U

Thanks George. The usable capacity (measured), was what I was curious about. Sounds like your battery was fine. I am still on 72mhz myself and using NiCads without problem. I'd like to gather more anecdotal evidence on new radios before I upgrade. I hate to waste $500 worth of 72mhz receivers if they still work. Realize that using NiMh or Lithium or whatever..one still needs to check capacity in MAH fairly regularly to spot a battery trend (I log all my batteries in a notebook with dates of purchase/capacities/cycle dates/highest charge voltage). Any other ideas, anyone? I guess I should work on wrapping up my own Mustang instead of posting!

You have the right routine also it seems Scratchbuilder! Are people doing a range check at the field each time? I know the new radios have a button or something to simulate a collapsed antanae for this purpose. Important to vary throttle during the process also. Well...that's all I got.

CGAV8R

My Feedback: (2)

Hi George. Were you running a voltage regulator?
Aaron

gmohr

Hi Aaron,

Nope, running nominal voltage right into the receiver.

Regards,
G

CGAV8R

My Feedback: (2)

Well I finally painted the stars and bars, 88, and fuel caps.

Aaron D.

rotccapt

looken good i am soo close its not even funny

Riddle4U

Looks Really Good Aaron! Make sure you are tuned up before the maiden...top of your game confidence-wise. Great job!