I am working on my first glow engine project and have a question about mounting the engine. The only way to get the engine to fit under the cowlingis by mounting it up side down. Iwas wondering ifmounting it this way may cause problems with idling? Can anyone give me some advise?</p>

Shouldn't. Currently 75% of my flyable aircraft have upside-down (or horizontal) engines. I prefer the muffler blowing down.

Thanks. I have had a few electrics that I have put together but this is my first glow engine. I figured it would be fine but just wanted to make sure before I did anything.

I agree with Charlie. I have a pair of 90 size pattern planes, both with upside-down mounted OS 1.20 AX engines. They can be a bit of a pain to prime, but I learned to put my finger over the exhaust and prime it that way. But, properly tuned, just as any other glow engine, it should start and run just fine.

I did NOT have the same luck with the Evolution 1.00NX engine. That's what pushed me to the OS engines... which, once broken in and tuned right were.... are just fine.

CGr.

Ibid on all of the comments above...

Most of my glow planes have inverted engines. I have never adjusted tank heights as well.

All fly great.

You need to exercise a bit more care in tuning, and to make sure your plumbing is good... but that's about it.

The only engine I have worried about inverted is the OS91FX in my GP PT17 Stearman. I've had trouble with another OS91FX and had to do some mods on it just to get it to run right side up. I'm going to put an on-board glow system on this plane just to prevent flame-outs on landing.

I have found that keeping the tank outlet and carb inlet at, or close to, the same level works best.

A similar event like the gentleman above described: After being run well on a bench, an inverted 91, would not idle correctly AT ALL when in the plane.
Reason : Because the tank's output was at least one inch higher than the carb's inlet ( viewed/measured as the plane sits normally on it's gear) , I failed to accept the fact that this "might" cause problems, even though I took notice as I was assembling the ARF!
Fix: Relocated tank (major alteration), and she purr's like a kitten!

Another thought: Unless you are committed to your current project, for your first nitro model, I recommend a model with an upright engine installation.

Just my $.02 Good Luck!

The only negative on upside down engines is that they can flood easily.

I had a Moki 210 in H-9 Edge 540 and the fuel system would syphon through the carb and flood the engine when sitting for a while with

a full tank so I would pinch off the feed line with a hemostat till I was ready to fly or I wouldn't fuel until I was ready to fly.

Always use THE BEST GLOW PLUGS, they not only last longer but they make your engine much more reliable and reliability = FUN.

JD-
Good suggestions here. Do what you can to get the tank at or slightly below the spray bar, use a good glow plug. Can I ask what size/make engine you're using? And in which plane?

The only downside, assuming you break the engine in and tune it correctly, might be that it's tough to get as low and idle as you want. As an example, I have two Saito 1.50 one on an Extra 300 and the other on a 1/4 scale Cub. The Extra is no problem. But the Cub, due to it's low overall weight, liked to roll at the lowest reliable idle I could get (about 2000rpm). I then installed a glow driver, the reliable idle dropped to 1800 and all is well.

Augie

The engine manual usually gives guidelines regarding installing the engine. You have not mentioned which engine though.

One thing you have to be careful with inverted engines is that when sitting fueled and waiting your turn, any fuel in the crank-case will slowly flow down into the clyinder. Then, when you apply the booster and try to flick it over, it will backfire. Be mindful of this if you dont want cut fingers1 This is also the reason why they flood. If this happens, simply create a siphon by raising the fuel line to just above tank level and then down again to the engine. This will prevent excessive flow. You can hand start most vertically mounted engines but in either case play it safe and use a chicken stick atleast. Dont ask me how I know

Ameyam

It really does NOT cause problems.

You would never be able to throttle down, with the plane in any position other than level if tank height was so problematic to idling.

In a nose up situation a typical ARF has the fuel a good 6-9 inches below the carb's inlet, yet it will still idle just fine once the engine is PROPERLY tuned.

No, the only reason to worry about this is to avoid siphoning while the engine is NOT being used ( e.g. the engine will fill with fuel ).

One started it's not a big issue.... PROVIDED your PLUMBING is OK.

If your engine does not idle when on the plane and your attempt at adjusting the tank height seemed to have cured things, then it is MOST likely that you solved a minor flow or plumbing problem while you were at it.

I stand firm on my comments due to experience.

Manufacturer's suggest an installation for many reasons. Mainly for best results and secondly, for unnecessary returns.

Excluding pumped engines, an engine seems to run best when it is forced to draw fuel ie: tank outlet slightly lower than carb. inlet.

More on the plane I had problems with: First, with the tank mounted way above the carb, not only did it not idle properly, overall throttle operation was erratic. At this point with a new plane never flown, it remained on the ground. All basics were then performed: Plumbing check including inside tank, cylinder head and rear crankcase cover bolts, glow plug, fuel, carb. mount O ring, muffler...etc.

After the next attempt: same results=N.G.

Repeated all the above= still N.G

Back home to the "drawing board"!

Re-located tank= JOY!

An engine creates more vacuum at higher throttle setting, therefore, it should pull fuel from a greater distance or even an improperly located tank.

There is no siphoning of fuel at all when the engine (In this case an OS91) is not in use. However when assembling the plane at the field, the glow plug is always removed and the engine spun to check if siphoning did occur.

Maybe relocating the tank was a solution specific to only this particluar OS91...but I honestly don't think so.

Tank height within reasonable parameters is the most common reason for frustration and folks frustration with inverted installations. It of course has a hugh effects on syphoning and hydro lock which can and does often cause engine damage and frustration come time to start the engine. Different starting and sometimes even handling protocal must be observed such as always carrying the airplane nose up when it is carried after fueling to a starting location. Simply fueling up and sitting in the hot sun with an excessively high tank locations will start a syphon and a likely loaded cylinder.

Yes of course inverted installations can and do work fine but you will be sorry if you do not make any effort to maintain a resonable tank/spraybar height relationship and of course I have and continue to use inverted mounts on occassion with the side mounting being my favorite.

John

It is a Nitro Planes .25 Yak 54. I have read this is not a quality plane but a friend had it in hisgarage collecting dustand passed it along to me for pretty much nothing. The motor is an OS 40 FX that my friend also had. figured for the deal I got on them I would make it work.</p>

I have a tuncano 40 with an inverted fox 45bb engine. Will not start right side up. I get hydrostatic lock everytime. I just flip it on it's back in the craddle for starting, once it's running it's fine. flip it on it's wheel's and fly. A remote glow driver is also a big help with starting planes with inverted glow engines.

OK finally the rest of the story, indeed you have taken on a handful to make it work. First the airplane:

I have not flown that one however I lhave flown many of the nitro planes and tested them for folks including the 25 sized gee bee. In your first post you said this whole discussion was over getting the the engine entirely within the cowling, well this is not going to happen even with a 25 size engine much less the hot .40FX.

Doing what you suggested involves going full inverted and raising the thrust line vertically withing the cowl and even that is debatable. This is going add additional aerodynamic changes in the airplane and that is a terrible idea. You have not even considered the cutouts for the muffler. Finding a pitts or box muffler that will fit and be completely within without drastically changing the thrust line is not going to happen either.

Do not raise the thrust line use either use a sideways or 45 degree down mount and make a hole around cylinder exposing it for glow access and a bottom center hole (large) aft next to the firewall for cooling, do not omit.

If you use a stock muffler a simple tunnel can be added as in the pictures of one of mine agine not the same airplane but one with almost identical dimension and cowl shape.

Now for the pilot:

This airplane is going to be a very cool and awesome little hot rod however in the hands of a first time glow flyer with only small electric flyer experiance and no mentor to smooth the way is almost certainly not going to survive long and this is neglecting the fact that this airplane is going to require a lot more runway than anything heretofore you have experianced and that means a park or back yard is in most cases definately out.

The very best advise anyone can give you at this point is find a glow mentor and get a real trainer preferably something of his choice.

Question why is it the mentors (ok the evil word, instructors) are always left out of the equation when it comes to choices in equipment but always the first ones on the firing line when folks demand answers when their bad choices go astray.

John

Hi!
For a newbie it is! Bad to mount the engine inverted that is...

And let me advise you that the plane you have choosen is not a good one for a first one... be it either glow or electric.

I agree fully with John in the above message.

A much better plane would be a high winged trainer like the Kyosho Calmato or anyone like it. There is lot's of them!

The best way to mount an engine is to mount it side ways!!

Thanks for the advise. Like I said I got the whole thing for dirt cheap so I thought I would give it a shot. If I were to continue this project what would be your suggestions on an engine for this plane?

Do just park it for a while and plan to get back to it, that is the reasonable approach. Indeed it will make a very nice little aerobat with a good modern 25. My preferrance would be an OS 25FX or AX. I really am a fan of the new AX line except the 46 which is an older design with the earlier remote needle carb.

The trouble also with the Nitro Planes most of them that is they are cheap for a reason and that reason is in three places. Customer service will not be on par with other majors, thats a given. Next argualbly the most expensive thing to develop to put in that box is the owners manual/instructions so they get around this by sticking in a simple pictografh that frequently is not even the exact same model and frequently the CG recommendations are dangerously wrong. Finally the last problem with many of these directly sold or small US resellers like Nitroplanes you find the hardware packages are often very poor quality, different from container load to load or simply unworkable.

So if you need no warranty or help from the reseller and you need no instructions to figure out how to assemble an arf and properly install and set the controls Then balance the airplane with no reliable info, finally can make his own decisions about which hardwards to use and which to replace then these airplanes many of them make fine projects and many are great flying airplanes.

If you must have any or all of those three items then stick to a major supplier, it will cost more but cheaper in the long run both in frustration and money.

John[8D]

inverted engine = perry pump time.

For lack of hassles and engine reliability in the inverted position, pump it with a Perry.
then you mount the tank in the cockpit if you like. Small mod to engine and problems solved from then on.

I'd love to convert all my engines to Perry to free up engine mounting considerations.

Hi!
A pump is not necessary in this case or advisable at all in 99% of all planes as long as you mount the tank according to the tank mounting rule!

Why convert from electrics to glow? There're 22 gabillion of us wishing we didn't have wadss of cash tied up in glow so we could easily afford switching to electrics!

This is of course a Ford Chevy thing but I can answer your question quite easily, why convert from electric to glow?

Simple its because of the rise in electric flyers most of the attention is going there simply because thats where the bucks are to be made and as a consequence there is very much a dearth of smaller RC glow models avalible especially in the .15, .25 sizes.

Now is just so happens thats many of those nifty and 'Light' electric models actually make excellent conversion back to glow and with inproved performance because of the lighter design techniques.

So indeed while we may not be numbered in the "gabillion" there is a ground swell who are taking advantage of many new electrics for conversion.

Of course I have also converted a few RC airplanes to controlline and you should have heard the howels of derision and laughter but little do they Know the joys.

John

that is true assumning the fuselage allows you to mount the tnak low enough. A pump removes all that uncertainty. Use it, don't use it

There is just something about the glow engines. I guess they seem more classic to me. I like the sound and smell of the engines. I guess that is the best reason I can come up with.</p>