rc-plane

i am about to buy a mustang pts ARF and was am going to buy a radio and you can but it with or without servo's. It comes with digital servo and i was wondering if they are necassary for the plane or if the regular one would work better???

plz comment back!!!!!!!!

opjose

This is a PTS thread so I have to ask, is the Mustang you are talking about the Hangar 9 PTS P-51 Mustang?

Pit-Viper 1

My Feedback: (12)

No they are not nessecary on this plane, when you get more time on it and want a better feel from the plane then you can. I used the stock servo's in mine from day "1" (103 flights)and never had a problem. I did go with a different radio and receiver though. I have one for sale if your interested, A Futuba 8-chnl. w/receiver. The only servos I use, unless in a large scale appl., are these ones here, with a 6V battery;

[link]http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXVW07&P=0[/link]


Shane

rc-plane

we were looking at the futaba 7 ch. that you could get one with 4 digital or one with like 2 i think so we were just wondering.

this is going to be my second plane i really did not know

thanks for the comments

rc-plane

i told my dad what you said and he said I did not ask the right question. He wanted to know what were the draw backs to using digital and would it make it preform better??

if you would plz comment thanks

Pit-Viper 1

My Feedback: (12)

My bad, I read it wrong as well. hehe Yes the digital servos will perform much better than standard servo's. It will be much more precise. I do believe they have a slightly higher power usage due to the higher resolution of the servo, a good 6v. NiMh battery is a good solution.

Shane

mcarlson11

I flew mine for the first time today. I am running a 11x7 3 blade prop, no speed brakes, and functional flaps. This thing pulled EXTREMELY hard to the left on takeoff, and when the tailwheel touches on landing.

This pulls really good with this prop. Very smooth plane, but becuase of the takeoffs, I dont think this is for a complete beginner. Flying part of it yes, just not the takeoffs.

lilwetor

Newbie here, with about 7-10 flights completed on my p-51 (that is after replacing half of the plane after to mishaps right away). I have spent the last 3-4 days trying to go through all of the posts and learn what I can. My main problem with the plane now is getting it to run smooth, I seem to spend my first 15 minutes of every flight trying to get the motor to run smooth. My questions is: Do you need to reset the needle settings everyday you go out to fly? Any help is appreciated!!!!!

opjose

If you are using the same fuel, flying at the same field (no changes in elevation), and the humidity is about the same, there should be NO need to change anything. Quite the opposite you WANT to leave things alone once you have the plane maxed out.

That said, the Evolution engine has one somewhat serious, but easily correctible fault...

Namely both of the needle valves will "walk", the low speed valve as you move the throttle forward and backward, and the high speed valve from vibration from the engine.

As per the suggestions here, I removed the high speed needle and bent the clip in to make it produce far more force against the detends. I also cut a piece of Dubro Exhaust tubing and put that around the high speed needle.

For the low speed needle I loosened the set screw, then tightened it against the metal plate, and screwed the set screw back in. This increases the friction when moving the idle setting.

With the engine dialed in, I placed a small wire tie around the low speed needle to prevent it from walking.


The low speed needle limiter "peg" may also contact the fiberglass cowl. Make sure that it cannot do so.


Finally if you have prevented the needles from walking, and you still find that you have to re-adjust everything prior to every flight, check your fuel system, as this normally indicates fuel flow problems.

Pit-Viper 1

My Feedback: (12)

lilwetor,
Tuning is fairly simple, just follow these steps.

Be sure to use the same fuel and clean the inline filter regularly, make sure all your pre-flight is complete first, then fill it up. Do not attatch the glow driver yet!!. With the receiver and trans. turned on, open the carb full open and place your thumb over carb opening. Then turn it over by hand a few times til its primed. Set your needles so that the High speed needle is 3 turns out from closed and the Low speed needle is flush with the outter edge of the throttle. Now go ahead and attatch the glow ignitor and be sure the throttle is set to about 1/4 open. Once it starts let it warm up for a minute before you start tuning it. Now start with the High speed needle, with the plane secure advance the throttle to full and start leaning it until you reach peak rpm. (On my motor once I hit max rpm's I go back 4 clicks and the tune is perfect.) Now if you have someone with you this is a good time to check it vertically. While it's running, have someone hold it nose up in the air and open the throttle fully, and if it starts to die "it is too lean", give it a few clicks rich and try again. Once its good try going nose up then nose down a few times to be sure.

Now the Low speed needle, I wouldn't recommend adjust this while it's running until you have more experience. this I adjust just enough to where it is smooth. With the motor warm, open it up fully for 1 - 2 sec. then let it idle for about 5 sec. Now advance the throttle to full open "quickly". What you are looking for here is the motor to go from low rpm to full rpm as smoothly as possible. If the motor spits and sputters before increasing rpms then it is to rich, if it just simply wants to quit when you open it up then its to lean.

Another way to check the Low speed needle is to get it warmed up, then open the throttle all the way then back to idle, (your just wanting to clear the motor out a little) then pinch the fuel line going to the carb. What you want it to do is almost immediately it should increase rpm's slightly for about 3-4 sec. then quit. If you pinch the line and it just keeps running then it is to rich, if it revs quickly then dies before 5 seconds, it is to lean.

Sounds confusing but its not that hard, if you need any help send me an email or PM me.


Shane

opjose

Isn't this also a sign of insufficient tank pressurization?

I have another plane that goes very lean nose up, and I have to back off the high speed needle almost 1/2 turn from "optimal - 200 RPM" to prevent the engine from leaning out so far that it shuts off.

That in turn causes level flight to be too rich and not produce optimum RPM's.

Thanks.

lilwetor

Thanks for all the pointers, I will try this weekend again and let you know how it goes. Just to be clear, if I have new fuel, a good glow plug amd have problems getting the plane to start, what is the first adjustment you make, the low or high speed needle?

Pit-Viper 1

My Feedback: (12)

If it won't start, lean the top needle only about a 1/8 turn each time and try it again. Just be sure it is open at least 2 1/2 turns when you start.

opjose,

the nose up lean bog due to tank pressure may be a problen on some motors, but on most 2 stroke motors, all you need to do is have someone richen it a little at a time while you hold it there. Then as i stated before I take the plane from nose up to nose down and repeat this several times with it at full throttle. When mine was set it would have a very slight bog when you went to the nose down position but was smooth with no hesitations going to nose up. Once that is set I don't touch it again all day unless I change props..


Shane

opjose

I have a couple of engines that do this, including one TH .46 and a couple of O.S. .46 AX's.

The Evolution does not seem to do it at all with the stock muffler and the baffle plate in place.

W/O the baffle plate I was getting it to occur, but not as pronounced as the O.S. engines. or the TH .46.


I guess my question should be, would increasing tank pressurization via a pressure valve help?

I'm a bit concerned about putting in a one way pressure valve. I understand that the amount of output from the muffler is quite low.
The one way valve requres a little bit of pressure to open the valve. But the amount required may be more than what the muffler puts out.

I've seen pressure ratings as low as .25 PSI being given and this seems less than what the one way valve requires to trip it.

Yeah I know that an ultimate fix would be a fuel pump.

---

BTW: on another thread Missleman insists that the TH .46 has tuning problems because of the leaning upon nose up.
I don't quite believe this as I see most engines doing likewise even when I bench test them.

---

For anyone following along... do yourself a favor and build yourself an engine test stand from scrap wood and a engine hold down with "pins", (Tower sells them as well as other sites).

It's amazing how much you learn about your engine's idiosyncracies, when you bench tune it, and how much time you save, that would have been wasted at the field trying to cure minor problems.

Pit-Viper 1

My Feedback: (12)

I'm not to sure about the whole pressure thing, never had any problems and I live around Denver (Mile High) and run my motors without the baffles. I was stating previously that that my final HSN adj. is 4 clicks rich from peak rpm, this is after I test it nose up. If I was to leave it without checking nose up it will cut out almost immediately after take off. A pump just might be the way to go but like I said, I don't know enough about them as I have never had any problems. Then there's my RCV motor, it spoils me as it doesn't even need back pressure to run at all. Something to do with the design of the motor pulls the fuel into it, ran it for over an hour with no pressure line on the stand and it never even hicuped.

My advise would be as I was taught, tune it on the ground then final tune it with the nose up on 2 strokes, 4 strokes are a little different.


Shane

opjose

Yes good advice... I was hoping to eek out those extra RPM's in level flight though...

rc-plane

I just bought an Arf and i was going to right down all the things i need to do. does anyone know what page most of the mods. start on???????

lanny2003

Here is a link to one list.

http://www.rcuniverse.com/forum/m_38...tm.htm#3901816

Scissor-Wing Transport

Great thread so far guys ! Thanks !

rc-plane

hey thanks for the link but i read most of the post and i was wondering if any one said something about making were the wheel goes into the plane stronger. does any body remember that??

stallwart

Short of opening up the wing and beefing up/ replacing gear mount, make certain the gear straps hold the wires tightly in the slots. Any slack, or wobble, adds momentum to the gear on a hard landing making damage more likely.

Pit-Viper 1

My Feedback: (12)

Take all the screws out of the landing gear and put thin CA in each screw hole, this will help prevent them from stripping or pulling out too easily. You can also use thin CA around the edges of the blocks to help hold them in place, they use what looks like Elmers glue on them. Should help until your an ACE like the rest of us... [sm=tongue_smile.gif] LOL J/K


Shane

SERRASOMETHING

I got the plane last week, got about 6 flights then, maybe 4 today.
Took off the speed brakes, made it faster, nose climbed noticibly, kind of a pain, not sure what I will do there.


The plane is strong enough, my model was 325, came with the 6 channel 10 model radio, real nice setup.

you only have a factory set of 75%, I kicked it up to 90% movement, little better.

the plane lands like a perfectly thrown frisbey, its strong enough, but, if you hop up the speed, and after a hard landing, I would go ahead and support the landing gear,

the plane is cool, flys well. I am happy with it.

With the current setup I am doing decent loops,

rw

opjose

Did you also set the flaps UP when you removed the speed brakes?

The brakes have a tendancy of pushing the nose down, the flaps push it up... so to speak.

Out of the box the stock setup balances out when both are in place.

If you have not done so, put in the flap servos and only drop the flaps for landing. You'll notice that the nose up tendancy will disappear if the plane is balanced out... though mine required 3 oz of weight on the tail.

Once I removed the flywheel weight, I was also able to remove the tail weights saving almost half a pound in total.

Brineymolly

Great thread guys ! Lots of great information here. I'm building my 2nd one, an ARF this time, and will post some photos when it's done. I'm doing a little customization on this one.

Here's a picture of the original.