fleist

i have recently crashed my hangar 9 pts mustang. thinking of going to a nitro model .40 ultimate bipe. wondering if the motor from the mustang with work and if it will what prop to go with

Sourkraut

I have the World Models .40 size Ultimate Bipe and it is almost identical to the Nitro Models. The Evo .46 PTS engine that came in your Hanger9 PTS Mustang will be more than enough for that little Bipe. I am running an OS .46 fx in mine. As far as props, I would use an 11x5 or a 10x6 2 blade APC or Master Airscrew.

fleist

thanks for the info, i think a will try it out.

opjose

How far did you get with the PTS?

If you were confidently flying the PTS in full sport mode, you'll find the Ultimate just SLIGHTLY more difficult, particularly in landings.

It will yaw much like the PTS at run-up.

On a deadstick the Ultimate is a winged brick however... so hopefully your engine is running reliably by now....

With a little throttle it lands easily though... and is a fun plane...

The smaller wingspan also makes it easy to toss into the trunk fully assembled for a quick flight.

fleist

still putting the plane together the instructions are horrible, the motor runs very reliable when in the mustang, i wrecked it doing a spin and when i tried to recover i pulled up to hard and stalled it sending it straight into the ground, so i figured it was time to try a acrobatic plane i am a little nervous that it will be to unstable. but you have to start somewhere. i do have a question about the mounting of the motor, i was planing on mounting it upside down and centering it on the fuse, is this the right way, and if so the muffler is going to be a tight fit, so do i turn the motor or do i get an extension for the exhaust. also any advice on how to cut the cowling,

opjose

I have several of these planes and I've done both inverted and side mount engine installs on them.

If you use a Pitts style muffler a side mount is the easiest way of dealing with the engine.

I like the inverted mount for looks ( since you don't see the cylinder head/glow plug cutouts this way ), but mounting the muffler is more difficult if you are using the stock muffler.

With an inverted mount I had to put on a muffler extension to bring the muffler out far enough to clear the cowl.

Putting the cowl on and off is also more problematic with the inverted engine, as I have to remove the muffler to get the cowl off.

Then the muffler screws are inside the cowl so getting at them is not easy, although I have two access holes to remove them.

I'd suggest the side mount to you with a Pitts Style muffler for ease of setup. Also removing the cowl will be MUCH easier.

da Rock

It will certainly be more acrobatic.

It's stability won't be less safe, it just won't be as self-restoring. And it WILL roll quicker and pitch quicker. Response to input will be appreciably quicker.

Have you flown with dual rates yet? And exponential is a good idea too. Keep in mind that acrobatic designs are designed to snap roll. They basically have elevators that're effective enough to stall the wings, but you can tune the low rate throw to make that easier to keep within your control.

fleist

i am using a spectrum dx5e radio setup and it has hi and low rates, i use the radio in the parkzone f4u corsair right now, but i dont think you can tune the low rate on this controller.

opjose

The LOW rates default to 70% of the high rates using that TX.

Set your high rates to equal the recommended throws and you'll have a docile flyer to start with.

Later I'll bet that you'll want more throws, and will probably want to max out the ailerons and increase the movement of the elevator and rudders.

You can do this mechanically... e.g. move the linkage on the servo horn OUT and the linkage on the elevator or rudder horn IN.

Unfortunately the dx5e does not permit you to adjust servo travel...

fleist

should i do the opposite to start with to get less travel, i am not even finished and am already nervous about flying it into the ground, but i guess everybody starts somewhere.

da Rock

It's always best to setup your surface throws with your TX throws set at 100%, and do all the adjusting on the airplane. This way you get maximum resolution (accurate response to stick movements) from the system, from the stick all the way to the surface. It sounds like your TX is going to be at 100% throws no matter what. And that's actually a good thing for starting flyers.

It's really not such a bad thing that the TX doesn't allow servo travel adjustment. Yeah, it's very convenient to have but not really inconvenient to not have. Setting throws on the model is simple and easy. Once you learn the drill.

fleist

another question, i was thinking of mounting the engine inverted, its a evo .40 i heard some rumors that this causes flooding, any suggestions

NM2K

My Feedback: (14)

You really don't want to mount a two-stroke glow engine inverted - ever. Unless you enjoy tinkering and playing with engines in order to get them running.

Besides, in order to have a good running setup, you MUST have the carb's spraybar at least even with the fuel tank's centerline, or have the tank centerline up to 3/8" lower than the carb's spraybar centerline. This is to get the engine to pull fuel equally whether upright or inverted. Four-stroke glow engines seem to be a little more tolerant of a high fuel tank, but even then a high fuel tank compromises the best possible running condition.


Ed Cregger

opjose

Respectfully... HUMBUG!!!!

I run almost ALL of my engines inverted w/o any problems what-so ever.

The spraybar to tank centerline height is overstated. It only affects siphoning, which once the engine is tuned is not a problem at all.

We would all have nothing but deadsticks the second we pointed the nose of a plane even slightly up if this were actually that sensitive as made out here.

If you can't run your engines inverted, you are not tuning them properly or there is some other problem.

NM2K

My Feedback: (14)

Opjose, you must live in a different universe with different physical laws is all I can say. Otherwise it would be edited by a moderator. Have a nice day.


Ed Cregger

opjose

Nope, this "inverted engines are troublesome" business is a bunch of needless and misinformed hype.

I've run dozens of engines inverted with NO CHANGES to the fuel tank height as well.

I've also helped others to tune up their planes when they THOUGHT that they had an "inverted engine" problem. A few minutes spent fixing their real problems makes them believers.

Once the LS needle is properly set the amount of siphoning that occurs is so low, that the fuel tank position is not a big issue at all. At idle even pronounced siphoning should be nothing more than a very SLOW drip...

Pointing the nose of a plane even 20 degrees up, drops the fuel tank height well over 2", yet those planes ( once tuned properly ) continue to run just fine... so what is the problem?

It's not the height!

On RARE occasion a trouble some engine ( notably where fuel drowns out the glow plug ) can be fixed by installing a longer plug, but short of this, there is no difference.... we would also be loosing planes every time we perform a roll in flight as the engines flip over.


If you can't run an engine inverted, you either haven't tuned it correctly or there is some other issue that you may have over looked.

There is NO need to FEAR inverted installations.

I have 2 of these .40 Ultimates with inverted engines and all do fine thank you. No other changes were done to the plane.


Hopefully the moderators can edit the universe of those who espouse inverted engines as being problematic.

NM2K

My Feedback: (14)

No, Opjose, it is not misinformed hype. You simply do not have enough experience to know the difference, that's all.


Ed Cregger

opjose

Let's see, 24 inverted engines running just fine thank you...

12+ other people I've helped with their inverted installs.

If that doesn't qualify as experience with inverted 2C engines I don't know what does.

But I'll stick with the "misinformed hype" unless someone can PROVE otherwise...

Thus far you've given me nothing...

Paging "Downunder" you are needed!

NM2K

My Feedback: (14)

Um, let's see, you have a ton of experience and I believe you. But you went through the struggle of learning how to make inverted engines run properly, right? So, it was not immediate success. In fact, it was probably very frustrating for a while, but you persevered and conquered and tamed the beast. Am I on track here?

If so, we do not disagree. All I'm saying is that it is more difficult to set up and learn the tricks of running inverted two-strokes. I did not say it was impossible, not once. I don't recommend using inverted engines without warning the unsuspecting modeler of possible problems and a steep learning curve. Remember, we live in an era when many new modelers are deathly afraid to adjust the needles away from their "factory settings".

Why do you have such a big chip on your shoulder today? I don't mind when people disagree with me. I do mind when they are disrespectful. Lord knows, I've been disrespectful myself when I had a bad day elsewhere.

All I'm asking for is a bit of politeness. I would provide that even if I knew the other person was dead wrong. I don't come here to fight or be insulted. You and a few others need to ease up a bit. There is plenty of room for all of us.


Ed Cregger

opjose

I really wouldn't say that it was any more difficult than tuning a normal engine, however you have a sligntly tigher tuning window and you have to be aware of this. That's the only real difficulty.


That's just it, it really was not difficult. There are many who scare off people telling them NOT to run their engines inverted.

If anything they may be better served in the long run by dealing with it.

I'd agree that it's NOT for the first time flyer, but here is a guy in this thread who wants to know how to mount his engine.

I suggested a side mount for him, but an inverted mount is equally successful.

I have several of these planes with the engines both ways. One is not more problematic or difficult than any of the others.


I'll certainly grant you that! Heh.

You certainly did not deserve that.

Sorry... bad day I apologize.

Sure no problem as long as you know I'm ALWAYS right!!!

Just ask my wife!

da Rock

There is plenty of room for all of us.

Where lots of inverted engines give problems is with starting. That is real and happens often. And it's probably where a lot of the blanket criticism of inverted engines got started.

I put an OS70 4stroke into one of my taildraggers awhile back. I knew to be careful about running the plumbing to keep siphoning at bay. I figured the taildragger stance would help some. The engine proved to be almost impossible to deal with inside the cowl and with the couple of different plumbing strategies I tried. I've got A LOT of experience with 2strokes inverted that had to start 1st flip in competition or you lost points. They also had to perform near perfect once you got 'em running within the time limit. And almost everyone of the guys who flew that competition flew inverted 2stroke engines. So I knew I could swap in a 2stroke inverted. And in went an OS46AX. Used the same motor mount as the 4stroke. Only had to cut the cowl for the muffler. And it started and ran flawlessly from the gitgo. No special technique to fuel it or get it to start. And in this installation, no special experience was needed. The plumbing wasn't exotic or done differently than any newbie would have done it. Both methods that were tried with the 4stroker were standard setups. Only one of the two was done for the 2stroke because it worked with that setup and never looked back.

I have a number of models with inverted 2strokes in 'em. Because of the cowls and where the pressure taps are on a couple, I use a hemostat to pinch a line to stop siphoning from starting while fueling. Those could be plumbed differently and the hemostat wouldn't be needed, but I like that plumbing setup. But all my inverted 2 strokes work great and all have since the 50s. Getting any inverted engine started easily depends on the plumbing and how you deal with what plumbing you installed.

opjose

As always sage words...

Yup I've seen newbies effectively flood their inverted engines and then blame it on the fact that the engine is inverted.

After I show them that they should ONLY allow fuel to get to the carb, then hit the engine with the starter, they have no problems.

The usual priming techniques tend to flood the engines when inverted, especially on the 2 strokers...

fleist

wow thats allot of info for a little question, but hey i mounted the motor sideways mainly because of exhaust. ordered a pitts style muffler so i figured it would look better in the long run. just waiting for a couple of parts to show up need my muffler to finish the cowling and broke a couple of servos that i had forgot about. Then i also bought a kwik fuel fueling valve, never used one before so hopefully i can figure it out and get this baby together, it sure looks like it will be fun.

fleist

another question i have been running blue thunder 20% fuel is there better stuff or different % of nitro that gives better performance. I am not really into making my own since i have never seen it done.

opjose

Be careful with those quick fuellers, they can be quite problematic.

I'd recommend a "T" or a 3 line setup instead.

20% Nitro is a bit of overkill for most .46 engines. Most will run well with 10%, and 15% makes it a bit easier to tune. Likewise with the equivalent in 4C engines...

Starting off with 15% on a newer engine may be advisable, then later you can work your way to 10% and save the difference.