Hey, Guys.


I'm brand new to this hobby (gas planes, anyway), but already in love. I recently bought a tower .46 trainer RTF. I took the first flight today, and had a great time. just a couple of questions, first I notice whenever I get the plane inverted (even for a short period of time) when doing loops, etc... I can hear the engine lose RPM fast for just a second. Am I just getting a bubble in the fuel line? If so, what can I do to make it fly inverted without almost killing the engine?

Also, after my two flights I broke two props, both on the landing. what happends is I land perfectly (with engine at idle) then kill immidetly after touchdown, but I still roll for a couple hundred feet, then into the snow bank at mabe 5-10 MPH. The propellers were top flight 10X8 wooden. And they seemed to be extremly fragile, is plastic a better alternitive? what are the pros and cons, what brand should I get, also should I get the same size?

Thanks for the help.

I'm new too and just flew my Nexstar a few weeks ago for the first time. I haven't been into this long enough to be giving much advice...You would be better off with the nylon prop though. I hear the Master Airscrew props are the way to go. In any case, have fun and you'll get plenty of tips and good advice here.

If it's rolling that far, could your idle be to high for a slow landing landing? Not sure what rpm it should be, but someone here should.
venom

For the inverted flight problem I'd first take a look at your clunk. Is it stuck at the bottom of the tank and not getting fuel when you go inverted?
If you are running that far after touchdown it seems to me that you are landing too fast or the idle is way too high. It should be somehwere around 2000-2200 rpm. (lower is better) I would suggest the Master Airscrew or APC type props. They should last you a little longer. Just my two cents worth, hope it helps.

a decent and cheap prop is the Nextar stock one its 1.99 and has red painted tips http://www2.towerhobbies.com/cgi-bin...?&I=LXGAK9&P=M I ordered a bunch and had some left so I use them on my 46 sport plane it happens to have red covering also the master airscrew props are also durable and will last through a few prop strikes using a wood prop at this stage in your flying will end up busting alot of props and just costing you $$ without any real benifit you should be landing with your engine running and be able to taxi to the pits before you go to the woody's.
I still use the MAS props there durable and with the painted tips you can see the prop arc.

Agreed on the idle speed. I might change to 10-4 or 10-6 to slow things down just a bit. That 10-8 will really move the plane. On my Explorer 40, I ran a 12 1/4 x 3 3/4 with an OS 52 four stroke. All the speed I needed, and it would really pull when you hit full throttle. I seldom flew over 3/4 throttle with it. I broke a bunch of props, usually ground them down a bit hitting the runway. When I couldn't balance them out at 11" D, then I put on a new one.

I replaced the nose landing gear wire with a Dubro gear. That cut the prop loss by a bunch. The ARF's use some mushhy wire and it was bending back a lot. The mains could have used replacing also as you could see them squash out when you touched down at anything over greasing it in. Check your langing gear for being bent. The nose gear should point straight down, no back rake to it. If you can adjust the nose gear height, give the model the most ground clearance you can. Also make sure the main wires are straight, they should point straing down when looking at the from the side. You can squeeze together to increase ground clearance. Just make sure the plane is not setting nose down or nose up when setting on a table. You want it to be perty much level.

One more thing to try when you are nearing the end of the runway, a couple weaves back and forth will cut down the ground speed some. Just watch you don't flip the plane by trying to turn to fast. Just do this and then make the turn for taxi back to pilot area.

Last, the APC props are the best in my view. The are somewhat tougher than the wood ones, but they will still break. If you buy them by the dozen, you can save some money. It worked for me.

If you are constantly breaking props with an engine that is not running you probably are not mounting the prop in the correct position.

With the piston near the top of a compression stroke, the prop should be parallel to the ground. This keeps the prop as far away from the ground as possible when landing with no power.

As to the comments from the other chaps - they are correct also, the problem and solution have many variables.

Good Luck

I use to have the tower tranier also, but I put an O.S. 46 in it instead of the tower. I also put a 11x6 prop on it and that did slow it down from the 10x8 or even a 10x6 prop. I would try the 11 inch prop and see if that does help you out and also like others have said the wood props are easy to break so you may want to go to the plastic ones because they really do take a lot more "ground touch" than the wood ones do. I do fly both wood and plastic props on the same plane and I do not see any differcence in them as to how they both perform.

My 46 powered trainer also uses an 11-5 prop. I had been using APC props but, while very efficient, they tended to be brittle. My main gear is only 5/32" and pretty springy. A less than perfect touchdown and I was nicking the tip of the prop on the runway. I have a bunch of 10.5-5 props now!

A club member suggested changing to a Master Airscrew prop. Not as efficient as the APC but they can survive a mild prop strike without as much damage. Of course, learning to land better will help...

Hey guys thanks for the help.

I don't need to ajust the idle because the engine is dead when landing. I'm starting to think the tower hobbies "fuel proof" coating they put on the metal axles to prevent rust, is acutally acting as a lubricant. when the plane rolls it's like it has ball bearings, it just rolls, and rolls, and rolls. even when the engine is dead.

I have some backround in electric parkflyers, so I know how to land, (both of the first landings were perfect, no boucing or banging just very smooth.


Also, thanks for the prop advice. I will stock up on some plastic/nylon ones.

Just to re-cap on the first two landings (with broken props) I came in slow at idle then kill the engine just before touchdown and smoothly land. My problem lies when the plane is rolling forever I eventually ran out of runway and ran into a snow bank.

I heard about putting fuel tubing in-between the wheel collar/washer to slow down rolling, I'll try this.

Sounds like you're landing on pavement. In that case try the fuel tubing on the axle trick. That should do it.

This is strange. I land my students trainers both dead stick and with the engines idling on our paved runway and the plane doesn't "roll forever". Usually a very short (relatively) roll. They don't have fuel tube on the axles or any other gimmicks. SLOW THE PLANE DOWN. Try a finer pitched prop as it will allow you to slow the plane down better.

Just how far is "rolling forever" in terms of feet?

Also, when you touch down, are you touching all 3 wheels at once, or are you getting on the mains first and then lowering the nose? If you're touching all 3 at the same time, then you should be able to hold the nose up and slow down more than you have been at touchdown.

I also agree that an 8" pitch is a bit much for most trainers. Even though the engine is dead at touchdown, I think the airspeed on approach sounds a bit high, so using a larger diameter, lower pitch prop can result in a slower descent.

Oh, I forgot, if the engine is "missing" when rolled inverted, you probably have the mixture set too lean on the ground. Try richening up a couple of clicks.

If that doesn't work, then check over the muffler vent line to make sure you don't have a pinhole or some such in there. Also, check the clunk as mentioned above.

On many airplanes, the tank is set a little higher or lower than "perfect", and the result is often a change in mixture setting when rolled inverted. If the tank is too low, the engine can go rich inverted, and it can go lean if the tank is a bit high. Some trainers have the tank mounted high for ease of engine tuning and with the assumption that negative G's aren't going to be a common occurance for that plane.

Thanks for your help, guys.


I solved all of my problems, first I started landing on grass insted of a parking lot.

And thanks montauge for the tip on inverted engine "missing" just riching a couple of clicks solved the problem.

Also, I bought a master airscrew prop, and I've had approx 5-6 full flights including take-offs and landings with no visible damage.


Thanks again for everybodys help, I'm having no problems anymore! (Except that I don't have enough time (and fuel$) to fly!)