SIX GUNS

George, if you add some baffles in the cowl that would help a lot with the cooling if it where mine I would also
add an onboard glow driver that would come on at 1/2 throttle and lower that is what i am going to
be doing with my S.T. 90 in the P-51 I am building right now


Jim

gmohr

Hi all, thanks for the help. I really like the baffle idea, and I'll do that this week. I just need to re-engineer some things a bit so I don't have to "flex" the chin cowl quite as much to install/remove it. The needle valve extension for example needs to change a bit, or the flex might break the baffles out.

Aaron, post a pic of the new stainless when you get a chance.

Regards,
G

Edit: I'm running 15%.

Mustang Fever

My Feedback: (2)

George:

Can you post a pic of the bottom of your cowl?

scratchbuilder46

Sounds like you are on the right track about this. This is to me one of the great things about our hobby and this forum. We can pick each others brains for solutions and what has and has not worked for us. Part of the fun is designing a fix or a little bit better way to do something that the manf. may have not done yet. Ways to lighten without loss of strength, or adding some strength for larger motors, etc. Fun stuff to do and mull over.

gmohr

I'll post that tonight, Bob.

gmohr

Ok, here's the image of the current cowl. This pic is of the enlarged front intake, as I've dremeled out most of the "lip" that I thought I could get away with.

Regards,
George

scratchbuilder46

George, that looks pretty good!! With the exit opening around the exhaust pipes, it looks like you should get a pretty good flow over the head now. Just run her a little rich and you should have no problem. Rich on the ground a little leaner in the air.

gmohr

Here's the baffle I came up with. The "open" side is already pretty much fully baffled by the header portion of the muffler. I think with this and the other changes, I should be good to go.

Regards,
George

rotccapt

that ota do it

Mustang Fever

My Feedback: (2)

It's difficult to tell from the pic, but you might want to enlarge your exhaust hole. Mine was a bit larger than that, and I didn't have a pitts muffler that restricted some of it. (It looks like the can might be restricting the airflow at lot.)

CGAV8R

My Feedback: (2)

Hi George, that will work great. It will make a big difference of how much air passes through the cooling fins.
Here's a pic of the redone exaust panels.
Aaron D.

gmohr

Aaron that looks great... a bit more subtle.

Bob, I've taken your suggestion and opened up the exit vent quite a bit. If it overheats now I'm converting the bloody thing to e-power

cls8995

hey guys figured id ask around if anyone has a bashed up used spinner they willin to sell me.

im looken to make a mold using it to produce a fiberglass spinner

should be cheaper

thanks let me know if ya do

frets24

My Feedback: (15)

Try a bit of pearlescent blue thinned. I like the waterbased acrylics because it can be "erased" with alchohol if you dont like it and the alch. doesen't hurt the underlying paint job. If you feel like getting the really fancy rainbow effect get some pearlescent yellow and red as well.

Take a look at this thread and there's more info on exhausts. Index on pg1 and another index on pg30

http://www.rcuniverse.com/forum/m_94..._1/key_/tm.htm

gmohr

Well guys... bad news.... she's gone. And in spectacular fashion. I've never seen anything quite like this. Here's the story:

After about the fourth flight of the day, I really got the plane trimmed and engine working perfectly (no more overheating, all those mods worked great). Took off for one more flight and was starting to have fun. Did a split S to a low downwind pass, full throttle. At about mid field, suddenly she broke into a vertical climb (still at full song). I had no radio control from this point onward. The plane climbed like a homesick angle for about 500 feet, then began to pull over the top into a series of loops. These loops continued for the next 10 minutes, all the while climbing and blowing downwind into the wilderness. At one point, we were all standing slack-jawed as we listened (couldn't see it anymore, too high/far) for the sound of the engine to finally run out of fuel, which it must have done. The plane was never recovered. Here's our analysis of the crash:

1) The receiver never entered fail safe (or it would have gone to low throttle (and yes I checked the bind point for low throttle)).
2) The receiver never lost power. I figure that an unpowered servo would have blown to neutral in those full throttle powerdives on the backside of each loop. Additionally, I checked the flight pack just before that flight and it was fully charged.
3) I built a straight and strong plane I've never seen a plane that could fly itself for 10 minutes, and those loops were perfectly straight. I wish my pattern plane was so straight.

Our best-fit scenario is that the receiver crashed or "locked up". It was a Spektrum AR7000, and a well used and reliable one to this point.

This is the worst loss I've ever experienced, as the plane was a real looker and promised to be a fun ship for sure. And I've never failed to recover the wreckage before >:-| BUT! The good lord taketh away and some times giveth a little bit back... my Yellow P-47 kit showed up today!

Regards,
George
.

frets24

My Feedback: (15)

That is so heart-wrenching. I'm sorry for your loss.[]
looking forward to seeing your Jug build.

rotccapt

sorry bout that man that stinks

Mustang Fever

My Feedback: (2)

Geez, George, that's really sad.

Something to think about: I have seen maybe 20 accounts of problems like this with Spectrum 2.4G. I have seen one with Futaba FAAST, and have had no problems ever with the two FAAST systems I use.

gmohr

Thanks, guys Its all part of the RC game, I guess...

Bob, have you had experiences with this sort of lockout on Spektrum where a power loss was ruled out? I know that Spektrum is more suceptible to brownout due to low voltage, but I'm all but certain that didn't happen here. The best analogy I can give is when your PC "locks up" and you have to reboot, that's what it felt like.

Regards,
G

scratchbuilder46

George, let me add my name to the list of those who are sorry for the loss. It is tough to loose a bird any time. It is especially hard when a lot of time and effort goes into "the one". I had a TF AT-6 that had 5 flights on it, dialed in, was a great one to fly and lost it to a bad battery pack. 400 ft. crater job. I hope you can retrieve it for the parts, it is a shame to see it go in, but harder not to get anything back. Any idea of going after it? You may get lucky.

FallDownGoBoom

My Feedback: (1)

George... that's a shame. Sorry for your loss. That's almost the same story as what happened with my P-51, except it was the maiden flight. Take off and the first seven minutes of flight were fine, then I did a roll and the next thing I know: no control! She started a right turn, the wing dropped, and death spiral from 200 feet. Nothing left but splinters.

Our crash theory was that the last roll pulled the battery out of its mount and pulled the power cord out of the switch.

One bizarre theory: could your elevator servo somehow have jammed at full up, pulling the battery pack voltage down below 3V? That would brownout the receiver, and assuming the servo stayed jammed the plane would have kept trying to loop, and receiver would never re-bind. Admittedly, this is not likely, but neither is 10 minutes of flight after loosing radio contact.

Again, all my sympathies on the crash of your Mustang.

Fred

SIX GUNS

GEORGE THAT IS hard to live with I lost my p-51 on the 1st flight it was only 30 sec. long so I know how you feel this is the 20th time
that i have herd of a 2.4 system crashing it makes me wonder if all of the bugs are worked out of these systems I dont know if I will ever buy a 2.4 system with all of the problems that I have seen theres not much any body can say but sorry that it happened
when mine went in I could'nt even look at the thing for a month ., we all, grow, learn, and fly some more

sorry george

CGAV8R

My Feedback: (2)

Hi george, really sorry about your plane man[&o]. That's really wierd how all that happened. Straight and level across the field, then up elevator, then neutral for awhile for the climb, then up elevator again to do loops. "What if" Your battery came loose and unplugged (no power to go into failsafe) and lodged in the very back of of the plane creating a tail heavy CG, causing the climb, it would cause it to go straight up until it slowed down and stalled, then go into loops because of the tail heavy CG. Where was your battery located? I'm just throwing out a thought, probably way off, but, it's a thought. I have been using several ar7000s for over three years now and no problems at all.
I've flown a yellow P-47 with a g-62 and they are great flyers. They land super slow. You'll love it.
Aaron D.

gmohr

Thanks again all... if I were Jewish I'd say we're all Sitting Shiva for this bird

Aaron, I doubt the battery came loose, but anythings possible and it would fit the scenario. However: I placed it just in front of the aft-most former in the wing saddle bay. It was zip tied to the cockpit floor with a fairly beefy epoxied hardwood block, and the zip tie also went through that rear former. In addition, the pushrod tubes would have kept it in place even if it did dislodge. The moment of failure was basically at 1G. Also, I'm pretty anal about stuff, so I use heat shrink tube to secure the battery and servo connections, and zip tied them to the pushrod tubes, I'm pretty sure it could have drug the battery behind it like a glider on tow

I've reiterated the scenario in posts on the Radio forums, lets see if anyone else has seen this. I'm going to email Horizon support also. I too have felt the AR7000 was bullet proof, I've been using them for 3 years.

OSUAV8R

Hi George,
  I am so sorry about your stang.  I have lost two airplanes on first flight.. so I empathize..  I am beginning to think.. I will do high speed taxis with mine and thats it....HAHA
But seriously.. she was beautiful and I hope some day you find her.

that said.... I am Jewish and will say Kadish for her in Shul

Nate