Hi, I would like to here some thoughts on mounting 2 stokes inverted. I have been in the gas planes for years and now am doing a glow twin. The cowl is set up better for inverted engines. can still mount sideways, just more cutting. any thoughts would be helpfull
Thanks.

Chuck.

The problem with mounting 2-strokes inverted is that if they run too slow or too rich, the glow plug will get a puddle of liquid fuel and oil in it and go out, causing the engine to quit.

Generally, you will need to keep the idle a bit higher, and your mixture settings will be more critical than side or upright mounting. A hotter running plug (maybe even a 4-stroke plug) can help some.

Also, if you manage to flood the engine, it becomes basically impossible to get the liquid fuel out of the engine without either removing the plug or flipping the plane over, since there are no ports or anything at the top of the cylinder. On the plus side, you won't have a problem with a syphon effect filling the engine as the carb will also be pointing down, allowing fuel to drip out of the engine inside of into it (assuming normal front carb design).

Gassers don't have these problems becaue the fuel-air mixture is much leaner than with glow, and the spark always happens, it doesn't rely on just the right amount of pre-existing heat and reaction between the fuel and plug element.

I prefer mounting them sideways and running the exhaust out the bottom. Easier to start, usually looks better than that big muffler hanging out the side, less critical to adjust, and gets the carburetor that much farther from the dirt of the runway.

I totally agree with everything the two previous advisors told you, therefore they are geniuses and gentlemen and you should listen to them and do what they say.

No doubt somebody (probably one of my friends) will chime in to insist that inverted glow engines are OK, you just have to be good enough at tuning them, which most of us aren't.

And I admire them for it, but my answer to that is righteous:

1) Tuning an inverted glow engine is more difficult and delicate than tuning it upright or side-mounted, so even guys that can do it well will spend a lot more time tuning and a lot less time flying, AND:

2) Even perfectly tuned, the margin for error in an inverted twin is much smaller: little quirks like props and fuel and fuel lines and tank problems have a much greater chance of throwing off the mixture enough to kill an engine, AND:

3) Losing an engine on a twin has much greater consequences than on a single-engine plane....much greater chances of causing major damage to the plane.


GO SIDE !

Thanks guys, that was pretty much what i figured!! Just needed to here it from other people. I will go with side mount
Thanks again guys.

Chuck.

Kram, what a beautiful shot of that P-38!!!!! I wish I had as good photographers with me when I fly like you must.

ram:

Yeah, I'm lucky to have two friends: Lloyd and Starla Swanson, who are professional-level photographers with a special passion for RC planes.

They have shot Top Gun and other big meets, but always come to my little Multi-Fly every September here in Iowa. They have a special talent for catching planes in action and making them look even better than they do in real life.

Starla's shot of my B-25 dropping bombs got me the "Snapshot" spread in last May's Fly RC, and it wasn't any particular talent on my part that made the picture exceptional.

I sincerely believe a lot of the multi-pilots actually attend just so they can get the free CD of their (and others') planes' pictures.

mt

More of their work:

Sweet. How far are you from Ida Grove. I made it to one of Byrons events before he moved them and they went away. It was the year after the B29 had gone in, but they had a very impressive B-17 that had something like a 17' wing span. Flew great. It was a great time.

We are way closer to you and easier to get here than Ida Grove, which is about 100 miles west of here and not on the interstate.

Can't claim to put on the kind of show Byron did (yet), but we get some really classy planes and pilots: would be tickled to have ya: September 5-6, 2009

http://dlgoodri.public.iastate.edu/page10.html

Last year's "Best in Show"


mt

Awwwwwwwwwwww geez kram .................... you're going to make us blush!

L

FYI:

That "L" stands for Lloyd Swanson.

Whose new VQ-38, (in a completely unexpected return to this thread's original topic!) has inverted two-strokes, and the original owner was none other than TwinMan.

Have ya tuned 'em yet, swede5?

No doubt you'll have to put yer camera down to fly that one!

The plot thickens.


mt

Another pretty plane from last year's gathering: (inverted G-26's)

Kram,

Been working diligently on the Dual Ace. I took all of the recommendations about NOT flying a P-38 as my first twin to heart.

So ................ as the weather warms, the Ace is just about ready to break in the Magnum 52-4s (mounted sideways by the way), tune them, get them running reliably side by side, and then head for the field. As you can imagine the engine work that needs to be done is still rather involved ............................. well ................. maybe not for you experienced twin drivers but definitely for us beginners. [sm=52_52.gif]

Darn shame that you live a couple of hours drive out, else you would be recruited!

And as far as the P-38 goes I have been thinking on outfitting her with an on board glow driver system for insurance. I mean, why not? She already has landing gear brakes, fowler flaps, rudder gyro, aileron gyro, and a pair of really big 91 ST engines!

Ya ................ I'll probably have to put the camera down in order to fly ......... Fortunately for all of us Starla will still be taking the pictures!

L

I would love to be there. We'll see how it goes. I think you folks would enjoy my modified 38, and I would sure enjoy all the other multi action.