Hey Bob!!!! you should borrow your brother's Ryan's Rebel and use your poulan 42 on it I bet you it would fly SUPER great with that engine I think you have lots of torque and thrust for it!!!!

For the Giant Big Stik, all I had to do to get the balance right was mount the battery about 6 inches behind the servos in the tail area. I used a balance point about midway between their original point indicated in the manual, and their updated point farther forward. The airplane feels good on the elevator and spins well, so I'm going to leave it where it is for now. Sorry I didn't weigh the Poulan before mounting it, but I feel the installation is probably as light if not lighter than their suggested Fuji engine as I didn't use the spacers and standoff ply firewall; I just mounted the Poulan to the glow engine motor mount and mounted that straight to the firewall.

Generally, if a glow engine drops in rpms when you take off the glow heat, it could use either more compression, or more nitro. One of my Kioritz engines is maxed out on the compression and runs fine with premium gas in the gas/glow mix. The Poulan drops a few rpms when you remove the glow heat, so it could probably use a touch more compression or a touch more nitro, but it would be difficult to raise the compression of the Poulan, and I don't want to run multiple mixes of fuel, so I'm going to leave it as it is. ("If it works don't fix it") Right?

Note: I have a smoke tank, pump, plumbing, etc., in the nose of the airplane, and the fuel tank on the c.g. Without the smoke setup, it would probably balance with the battery mounted with the receiver.

AV8TOR

Ya..sounds great....lets cal the fuel Gas-anol or Gas-a-nol. Capt,n

GASAMETHANITRONOIL??

not sure if you local gasoline already has some alcohol mixed in ? Here's a quick test:
Source: http://www.eaa.org/education/fuel/knopp_alcohol.html

Yep. That's exactly right. I've done it many times. Gasahol is not recommended for use in aircraft, nor ultralight aircraft engines. In the ultralights with their two stroke engines, there is sometimes problems with the gasahol absorbing water, and then the oil not mixing properly. Result... the pilots "air conditioner" seizes and quits and he instantly starts sweating!!

AV8TOR

AV8TOR: Have you ever tried a tuned pipe on your gas/glow mix engines/ Thanks Capt,n

Hi,

No, I haven't yet. It will work fine though. The exhaust gas velocity and temperature, (which are used among other things to determine tuned pipe dimensions) would be different than either a pure glow or a pure gas engine, but easily within pipe length adjustments. Just start long, and shorten in small increments until you get max rpms. Then lengthen it back to the last step before you got max rpms and you're good to go. You probably won't see large gains unless your exhaust timing is about 150 or more, with as much as 170 or so being a good tuned pipe exhaust timing. As always, everything has to work together in an engine, so if your carburetion and port timing isn't working with the pipe, and all targeted at about the same rpms, you won't have a good combination.

Let us know how it works,
Good luck,
AV8TOR

AV8TOR: If I did the 155 degrees.....and did not use pipe....would it still be good running with stock (untuned) exhaust? Thanks Capt,n

Yeah, 155 will work with a muffler just fine. I have one running a muffler at about 164 degrees.

AV8TOR

Hey guys im into this conversion scene, but from an alternate angle.

Mine is for marine applications. As you guys would know, rpm is everything when chasing speed in a boat.

I have an 18.4cc weedeater, bog stock for now.

The prop i want to spin is a 65mm 95,1mm pitch octura prop.

I was wondering whether you guys see any advantage in doin all these mods to a marine motor, where weight is LESS of an issue then in an aeroplane?

On another note, i will have an advantage, of a watercooled head so perhaps if i go ahead with a gas + glow setup i may have some cooling advantages, in chasing rpms.

On a side note though, am i better off ditchin the 18.4 and goin to a 25cc GMC 2stroke motor (looks like a ryobi or homey cant b sure?)

Its going to be heading into a 50" apache style deep vee hull (if that means anythin) with a surface drive prop (only partially submerged, makes engine rev out more easily)

THanks guyz,
Ben

Well, you asked....

Ditch the 18cc motor or use it to make a gas powered "Margarita Machine". (blender)

The Homelite 25 or 30cc is probably what you will want to play with. There is a ton of info and lot's of people running them in boats, and you can find a lot of info, parts, and support. They will have much more power potential for about the same weight as your 18cc. Just do an internet search and you will come up with several websites on Homelites in boats. If you are wanting to run "Gas/Glow", there is lots of info here in this thread, or just ask if you have a question that hasn't been covered.

Here is one website to get you started:
http://www.warehousehobbies.com/index1.html

Scroll down and on the left hand side you will see "accessories." Click on that and the page that comes up has a link to Homelite parts and accessories for boats. (small print blue letters near the top of the page.)

Good luck,
AV8TOR

Changing to glow is not only the weight issue. My Poulan 25cc with glow has more power, starts easier, idles smoother then with magneto. Other issue is that the Poulan 25cc has very weak magneto support (the coil can vibrate 0.5mm up and down, so the gap between the coil and the flywheel must be big enough to prevent striking. With glow plug the coil can go away (I think you still need flywheel for the boat as the boat prop does not have as much inertia as a plane prop).

Also another thing you need to consider is that an engine without the flywheel has less weight/stress on the crankshaft thus meaning more rpm's and power for the engine.

Im probably going to run a homey 25 (see the GMC thread) with the clutch installed so i can use the flex cable that came with the weedie...

So in actual fact the fly is gonna have to stay.

THats unless it has an oil injection pump 8-)

Yeah, oil injection helps with that problem, but the alcohol in the gas effectively leans out the mixture throwing your jetting off. (In the wrong direction I might add.) So if you are jetted according to the manufacturer for a particular altittude and temperature, you are going to be leaner, (and more dangerous) for the engine than you think.

AV8TOR

I just tried my first gas glow mix conversion, using an old Ryobi engine. I used 2 parts regular gas and 1 part Mach 1 fuel 15% nitro as this is what I have on hand. I took an old Ryobi spark plug, knocked the guts out of it, turned a small brass plug to fit the hole, silver soldered it in place from the top side, used an end mill to clean it up, then drilled and tapped it to fit the glowplug. I tried a new OS # 8 plug and ran the engine, but it ran very poorly. Needle valve adjustments would not help. I then remembered having read in these postings about using an F plug, so I tried one and it made all the difference in the world. The engine will now go from idle to wide open without hesitation and will run as long as you supply it with fuel. I plan to try the mix on one of my flying converted ignition gassers perhaps tomorrow.
A question: I read where it is recomended to use premium gas and 10% nitro glow fuel for the mix. Will the higher octane gas make a difference over the regular? Either will run my converted ign. gassers and I can't see a difference.
W5RA

Question......a lot of differant glow/gas mixes has been tried by now. What seems to be working the best? Also what glow plugs work best? Thanks Capt,n

Standard fuel mix would be the use of 10% nitro with 10% oil R/C car fuel mix in a 1:2 ratio (33%) with a 91 octane gasoline, this will end giving you a final concentration of 3.3% nitro, 3.3% oil, 26.6% methanol and 66.6 gasoline; the recommended plug is the O.S. F plug or Hobby People's Four stroke and big bore engine plug (less expensive $5.49 and works just like the F plug)

Hey guys.
How about a 'fuel milage' ? Do you fly the same ammount of time on gas/glow as it would be on straight gas?? Okay how long would gallon of MIX last in say 31 cc ryobi ?

Does Hobby People have the adapters to install for glow plug? thanks Capt,n

It's a Zenoha number. ZEN23445

It's listed as Zenoha Gas-Glow plug adapter.

It says on the back of the package www.horizonhobby.com

Cost is $11.99. I ordered mine through the local hobby shop.

A 16 oz fuel tank will run for 25-30 minutes, and I can assure this because at one time my throtle got stuck and I had to fly my plane untill it ran out of fuel it lasted approx. 30 min.

Captain Hobby People doesn't sell the adapter but Horizon Hobbies does and it's made by ZENOHA as Ralph mentioned look on their web page!!!

ARE YOU SURE ABOUT THIS??????