ahicks

My Feedback: (2)

I can say that the slow return to idle is typical of a hot engine that might be just a hair lean on the low speed? As tough as that low speed is to get perfect on these 10's, unless it's making you crazy, or hanging long enough to be screwing with your final approach, I might have a tendency to leave it....

I just switched my engines to 13x6 (from 12x6) not too long ago. I went to grab the tach at the time, but it didn't work (batteries leaked) so I don't have prop rpm data of my own. I can share that the 13x6 numbers I've seen (going by memory), might have been a little higher than that - especially with the cooler weather you were running in. The engine was "peaked" that day, or could it have been done last in warmer weather?

I'm wondering if the engine might be lean on the HS needle?

Other than that, I'll say I love the 13x6 as it seems much quieter - with a noticeable increase in power/vertical performance over the 12x6!

flyinwalenda

My Feedback: (5)

Have you checked the linkage for binding? Servo in good shape? Fuel lines and tank in good shape and not leaking?
If the linkage, servo , tank/lines, etc is OK then I would suspect the low speed needle is a bit too lean. Try opening it a tick but remember the HS and LS needles work together very closely so the HS may need readjusting after.
I remember reading where someone had "idle hang" on a larger gasser and resolved it by simply adjusting the plug gap.
I haven't had this issue with my 10GX's.

bmcd

Thanks Brian, ahicks

I will open the LS needle a tad this Saturday. The engine was peaked just before the tacho reading. Note my temp was 28 degC (82.4 degF).
Linkage, servo, tank & lines are OK. This engine is in a Hangar9 Ultra Stick 40 and pulls it like a dream. (not one dead stick to date).

Joystick TX

I dug out the flight log for my 10cc EVO on the .40 Ultra Stick. The last RPM measurement I did on that engine was in December last year, so the temperature was probably in the 50's here. The engine had one hour of run time with the 10-7 prop. I was getting 10.6 Krpm for the Hi speed and 2.8Krpm for the low speed. I was using a Master Airscrew "Scimitar Profile" 13-6 prop.

I usually don't run any of my engines wide open, but for some reason, I like to fly the Ultra Stick at WOT all the time. It seems to me like the EVO power is about equal to a hot .46 two stroke. I only have four hours of run time on the engine now and went through the usual loose muffler problems. I stopped that by putting two screws through the sides. It still leaks some oil, but at least it stays together.

bmcd

I must check my idle RPM on the tacho. Never done that.

I read all the muffler issues before the first run. Following a wise 10GX owner at the club, I epoxied all three sections together and both ends of the bolt from new. I attached it to the motor with the supplied gasket and re-tightened while hot. Never had a muffler come loose yet, although it is now seeping some black muck from the front bolt hole and the front section joint.

Brian

bmcd

Opened my LS needle slightly to check the effect on "idle hang". No difference, so I returned it to where it was. Following Al's advice - It's not an issue so I will live with it.

@Steve
My idle is a fairly steady 2500 RPM when hot, so it seems within the norm.
I have a silicon exhaust deflector which may account for my WOT speed being a slightly low 9450 RPM

Brian

talk the torque

If its got a tinging sound when you bring it to idle and it idles high I would say the engine is getting hot and you need richen the top end a bit. 7 sec sounds like it could be this. If when bringing it to idle it just idles high for a bit (probably around 3 - 4 sec) and then the idle slows this to me would mean the idle is too rich and needs to be leaned a bit. I see this as coming to idle with the WOT mixture still in the combustion chamber and as the engine settles with the idle mixture coming through it slows as it is richer than the high end mixture

Joystick TX

What is slightly, a screwdriver blade width, or a quarter of a turn? I would turn it until you see at least "some" change. Richen it a little at a time, like 1/8 turn until you see a change in the air, or if it runs bad on the ground. The engine may also quit at any time in the air when you play with the adjustments, so make sure you have enough altitude, airspeed, and flying experience to handle what happens in the event of a dead-stick landing. Usually the engine is hanging out in the air on an Ultra Stick, so air restrictions, and carb vent problems, due to a cowl are not a problem. Also, the tank level on a Stick is pretty well fixed by the narrow fuselage, so that is not an issue. If your linkage is not binding, a hot engine is still my number one suspect. The plug gap may be an issue, but that is a long shot. It is easy to check and worth a try.

talk the torque

These carbs are also sensitive so make sure that you have the inline and clunk filters on. The clunk filter also helps prevent frothy fuel coming through the line which could also make the engine run hot

Joystick TX

That reminds me of something else that can cause a problem. It is also a really, really long shot. If you have a check valve, or something acting like it, in your muffler pressure hookup to the tank. That can keep excess pressure in the tank for a while after the throttle is cut to low. I have only seen that once, but it was also duplicated on the ground.

ahicks

My Feedback: (2)

Mentioned earlier that I had picked up a .46 size Phoenix Extra 300s. Have it built ready to test fly now. Mine turned out to be very nicely covered, needing no touch up. Only mods I did were to install tail wires (per lessons already learned on a Yak) and move the rudder servo in back (very easily done). If the suggested CG is anywhere near close, that move turned out to be unnecessary. Have some doubt there, because suggested CG is way ahead of the wing tube/30% rule. Will start at rear of suggested range and see how that goes.

Writing mostly because the aerobatic performance w/10GX looks pretty good on paper. Plane weighs 6.5 lbs ready to go, and with 600sq. inches of wing. That translates to 25 ounces per sq. ft. wing loading. Not a glider by any shape of the imagination, but not bad! I already know that this engine will have great vertical at this weight, based on experience with a plane that's no longer with us.

The kicker? This plane is 129. shipped at Tower - before any discounts.

Oh, and they say this thing comes with a one piece wing in the adds. Not true. They're plug in with an alum. wing tube. Download and look at the directions...

Maiden in a day or 2. -Al

jjoos99

My Feedback: (12)

Al
Lets us know how it maidens out. I had a phoenix edge that I put a .72 surpass in. Flew good but if you slowed it down too slow it would tip stall hard. Actually buried it on its second flight with a dead stick. Rebuilt it but it never flew real well after that.
Jeff

ahicks

My Feedback: (2)

Yes, nasty stalls are kind of what I'm looking for/expecting on this type plane on those early flights. Designs like this are not trainers or even good second planes. If you get it through those early flights though, my experience has been that careful control throw setup and CG positioning (normally way to the rear of suggested) can net you a plane that's much more civilized at lower speeds, will actually let you slow down pretty easily. Not at first though! -Al

ahicks

My Feedback: (2)

Plane has been maidened successfully. No nasty stall habits, plenty of warning she's getting ready to let go as it slows. Excellent vertical, close to unlimited but not quite. The engine was not running it's best and I didn't have a lot of time to get it much better. There may be a hair more left in it? Even so, this will never be a full on 3D machine on this power. I doubt it's something that's ever going to be able to pull out of a hover. Best case you might be able to slide out into a knife edge or something I think.

Knife edge, for a plane right out of the box, was very civilized. Very little pull/tuck, and NO coupling. This thing is going to rail when set up properly. I didn't have enough rudder authority first time out. Need to work on that. Could be a wimpy servo, linkage out too far on the servo arm, or even forward CG. We'll see.


I'm very happy to have found a good home for this baby gasser. This plane could evolve into my "go to" plane for this coming season. Encouraged by these first few flights, really looking forward to spending more time with it. Judging by these first few flights, would recommend the plane for somebody looking for a serious gas powered sport plane with compact dimensions. Intermediate or better pilot. Very easy/quick build with few mods required. Lots of room for ignition module, etc. up front.


Components:
10cc Evo GX
Bisson Pitts muffler
6 oz. tank
Single 1800mah A123, with 2 outputs, feeding 2 switches, both feeding power to the receiver.
Rcexl Optical switch w/BEC mod
Park model size metal gear servos on ailerons and rudder, rudder servo located in rear.
Std size HD metal gear servo running stock linkage (dual pushrods) for elevator.

Note: Side mounted engine required a very small hole (the size of a nickel?) to clear the spark plug boot.

-Al

Joystick TX

Sounds like a great engine/plane combo. I may go that route with my engine, getting tired of my beat up old Stick. I really like the idea of dual switches for the battery. That seems to be the weakest link in the gas powered planes. The 10cc gas engine may not be quite as hard on them as the bigger engines, but it does not hurt to have some redundancy. I have had two switches fail in my GSS, fortunately only one at a time, or I would have lost it for sure.

ahicks

My Feedback: (2)

I started doing it (2 switches) when trying to get enough amperage to prevent brown outs while using a NiMh battery. This was 3-4 years ago, prior to finding out they were complete garbage when used trying to fly something like a 30cc gas hot rod. Had a Funtana go in on knife edge prior to figuring out all I had to do was release the sticks to drop the current draw, allowing the receiver to "reboot" and get control back. Anyway, it wasn't long after the redundancy offered by the setup dawned on me, and I've been running it on everything since. Very easily justified, as you say, even on a 10cc plane....

sighh

I bought an evolution 10gx from graves rc hobbies when i visited orlando Last year. Finally last weekend I took the plane out for running in. I finished only one tank. Now I can hear that famous clicking sound. Now since no horizon support in Turkey I guess I need to take care of this problem myself. I thought maybe Pete would tell me what to do to fix the clicking sound.

JoeyCoates

I have one little item on the 10gx which cost me my Phoenix Decathlon last weekend. I was at fairly low altitude and did a stall turn at which time I had a dead stick. Couldn't make it back to the field and found a barbed wire fence on the way down. So I started to pull things out of the now deceased airframe and as I was pulling the fuel tubing off of the carb I noticed that the nipple that screws into the are carb body was not tight. Upon further investigation the gasket that goes in between the nipple and the carb body had completely deteriorated, it was mush. I can only assume that it led to an air leak at the carb body, there was a pretty decent gap where it had fallen apart. I have never loosened it for any reason so I do not know why it ended up a mushy mess, but it did. I have since replaced it with an o-ring and i am going to bench run it this weekend to check.

On another note I am thinking about replacing the Decathlon with a Great Planes Big Stik 40. I have not had a stik in 20+ years so I thought it might be a nice break, and they were always fun. I would pick up a Hangar-9 Super Stick if they were still available, but in typical Hangar-9 fashion they always seem to stop making the fun ones like the Funtana series. A Funtana 50 was one of the most enjoyable airplanes I ever had...

jjoos99

My Feedback: (12)

I picked up a nib funtana 50 this winter and have my new 10gx in it. I am anxious to fly it when the winter breaks. I had the funtana before and also loved the way it flew so i wanted another.
jeff

tandemairbike

I recently purchased a New Revolution 10cc gas engine and the owner's manual says to use a 10-6 prop for break in and a 12-6 for normal flight. You want to break it in in the air with alot of full throttle flying to heat the engine up to break it in properly. I am installing my engine in a Phoenix Model Dolphin designed for a .40 to .46. It fits nicely. I am using a 7 oz. tank. The only disappointment is makinbg a hole in the top of the fuselage for the plug and sensor wires. As this is merely a test bed I can live with that i guess.

JoeyCoates

Ok, after replacing the mushy gasket around the fuel nipple where it goes into the carb with an o-ring I mounted the engine on the bench to run it. Primed her up, 3-4 good flips and she was running. I am using an APC 13x6 prop and the recommended 20:1 mix.

Once it warmed up I tuned for peak and got 10k. Ok, not too bad, but I was wondering if the little dubro muffler extension I had on it was affecting the rpm's so I took it off. Instantly louder, but WOW, hitting 10.5-10.6k just like that! Also will hold a 1700 rpm's idle for days and transition to wot very cleanly. I do not even have a gallon through it yet but this little engine is really coming around!

tandemairbike

On page 10 of the Evolution 10cc gas engine owner's manual the proper break in instructions are given.

JoeyCoates

I think I have found a nice MX-2 airframe from General Hobby that was on sale for $130 with $22 to ship 2-day (I have heard good and bad about them, I latter found that RCjetsworld sells the same airframe for the same price) for the 10gx. It has a 57" span with 650 sq/in of wing area. Now supposedly it comes in at 4.6-5.3 lbs flying weight when electric. I am going to use a single battery for radio and ignition, Hitec 225mg's on aileron and a single normal sized digital servo on elevator and rudder. I have some Hitec 5945's I can use or a couple of Futaba BLS 451's or 351's for the elev and rud, will probably go with whatever is the lightest to keep the weight down.

http://www.generalhobby.com/skyline-...een-p-359.html


I have considered going with a 6oz tank as that would be plenty of flying time, but I may use an 8oz as I am concerned with a 6oz being so small that the clunk could not move around freely. I already have an IBEC and will also use an opti kill switch along with it. My 10gx is turning an APC 13x6 at 10.5-10.6k with the stock muffler, I also have a Bisson Pitts muffler but I need to run the engine on the stand with it to see where I am on RPM's. I would rather cut the cowl and take the stock muffler rather than loose RPM's as I would like to be able to pull out of a hover.

If I can get it somewhere around 5.5-6 lbs dry then I think it could be a pretty nice flying airplane, I just need to watch what is going in it. I am not expecting a full on 3d monster, but I would like some good performance. At 6lbs I would be looking at a wing loading of 21.27 oz per sq/ft which would probably work out pretty well. Some of the online thrust calculators say that a 13x6 spinning at 10.5k should make around 9.5lbs of thrust, but my own experiences say that this is not accurate. I would guess it is closer to 7lbs, maybe a tick more. Either way I would end up with a little bit better than 1:1 ratio which would work out.

The airframe is on the way, hopefully to be delivered by this weekend. I might do a small review just to see how this all pans out. From the experience that ahicks has had with the Phoenix Extra I am hopeful that this could end up being a nice, inexpensive fun plane to fly.

ahicks

My Feedback: (2)

Joey, sounds like you've picked a winner to me. Lighter with more wing area than the Extra I'm playing with. I know what the Extra will do already, so yours sounds like a winner! Be very interesting hearing your flight report...

I would have thought that by now I'd have more stick time with this plane (one of the reasons I'm in Fl.). Darn this wind! So still sorting, but making good progress. Engine was dying when I pulled back to idle. After a few adjustments and more dead stick landings I decided it HAD to be the low speed, and finally found it's sweet spot a little richer than what I had been running. Now the engine is reliable, and seems to be making good power. Got a chance to tach it finally. This one is turning an APC 13x6 at10.5K as well (w/Bisson Pitts). Vertical is,,, well, if you turn it into a dot you'll see it slowing, so I'll leave it at very good vertical for a sport plane. Huge maneuvers anyway.

I think you'll find 6oz plenty unless you plan on going cross country with it!

Worth mentioning maybe, ran into a problem I hadn't seen for a while in an ARF. The plane, when trimmed for straight level flight, had the left aileron noticeably above neutral when I put it on the bench, the right below. I did a lateral balance that required a couple of screws in the LH wing tip and tried it again. Some difference in the air, but still had ailerons out of alignment when retrimmed for level flight. Robart incidence meter was dusted off, fuselage was zeroed out, and the left wing was found to be twisted a hair. Removing the twist with one hand, while shrinking the resulting wrinkles with a heat gun using the other hand, resolved that issue. Now to fly again - with a straight airframe this time...

Last, regarding the 10x6 for break in. Go ahead, but I wouldn't leave it on there for more than a couple of tanks. The engine will turn up to something like 14k with an 11x6. That should keep anything in the way of excessive loading out of the picture. Then get the 12x6 on it soon after, and maybe spend some time with that prop. I was shy of going to the 13x6 for fear I was going to loose some power. Kicking myself for dragging my feet now... -Al

JoeyCoates

Ok, I decided to go ahead and try the Bisson pitts muffler today while the engine was on the stand. I first ran the stock muffler just to make sure my baseline was good and after warming it up it turned 10,500 just like it did before. Pretty good numbers if you ask me....

So after letting it cool down I bolted the Bisson on. I had to trim the stock bolts by about 1.5 mm as they were bottoming out in the Bisson, but after trimming I got it all snug. I started it and let it warm up, and by the way I never used the electric starter once, all hand starting. Once warm I ran it up and at about 10,800 it started to die from being lean. I backed it down and opened the high end 1/2 turn and ran it back up. Once stabilized I leaned it to 11,200 before richening it back to a stable 11k. Wow, I NEVER would have have guessed that it would have actually picked up rpm's, I was just hoping not to lose any! I actually killed the engine just to make sure I had put the 13x6 back on and not a 12x6 or something. Now I am really looking forward to getting the MX-2 in to build. This may actually be a really fun airplane!