Break-in prop and other advice

Time for more dumb questions. I just bought what looks to be a good Magnum .36 on the 'bay (cross fingers) NOW,

What size break-in prop should I use for: an iron Fox .19, a 40th anniversary Fox 35, and the Magnum .36, which will be converted to C/L as soon as our forum host can advise me.

What kind of glow plug is recommended for each of the engines? Is it possible to use the same kind of glow plug for all of the engines, and if so, which one should it be? Long or standard, Idle bar or no?

What is a good break-in fuel for the Magnum? Flying?

I just found a shop in a nearby town that actually has several gallons of Powermaster GMA all castor fuel for the Foxes! Now to mount the test stand and tank, and let her rip!

Now, the REALLY dumb question: The last time I flew, I used a 6 V. lantern battery,with lamp wire and alligator clips. Is that still O.K., or is there something else that will work better? Was the big lantern battery the reason our glow plugs didn't last too long back then? Do the little rechargeable units work reliably and well? Thank you for any suggestions.

LAST EDITED ON Jul-15-03 AT 11:52 PM (CDT)
 
The instructions with Magnum ABC engines specify a fuel containing 20% or more castor oil for break-in. I would break-in all three on Powermaster 10-29 GMA, and using the same glowplug...a long idle bar Thunderbolt, Zinger, or K&B. As for glowplugs, "Long" = "Standard". Engines .15 or smaller usually use "short", bigger engines always use long, AFIK. Not sure about some of the .18's and new weirdness. Both are available in idle bar. When in doubt, pull the head off and see which fits flush (idle bar will hang down into combustion chamber). Which .36 did you get, Square-ish or round cylinderhead? Use 10-22 GMA (11% castor + 11% Klotz) after break-in for the Magnum.

If you really used a 6v. lantern battery, you must have used long and small wires, or the glowplug would have vaporized instantly. I was reluctant, but the "Glow Ignitors" work quite well. I bought the DuBro with replaceable battery (two, actually, one charger). Be sure you don't leave it on the engine and launch, and be sure to remove it before fine tuning the NV. Steve

That "don't leave it on the motor" comment would, I suppose, be a reference to my little mishap last week. I can confidently state that:

- The Dubro unit has sufficient bite to remain clipped on the plug through all maneuvers. (What was I gonna do, go around in circles?)

- My T-bird really was tailheavy, just like everyone's been telling me. Flew a lot better with the extra weight in the nose.

- There is enough juice in one of those glo-driver batteries to restart the motor even after hanging onto the plug for seven+ minutes.

(Note to self: make a "remove before flight" pennant.)

>That "don't leave it on the motor" comment would, I suppose,
>be a reference to my little mishap last week. >
>- Dave

Dave:
No, not really! I have seen folks do that years before, came close myself. I admit that I use 'em, but I'm not really fond of the concept. I'd vote for a "safety thong" requirement for them. I think you can get a "Remove Before Flight" ribbon at the Pilot's Store and similar places (Boeing Field), probably online also. Steve

LAST EDITED ON Jul-16-03 AT 02:44 PM (CDT)
 
Steve: Thanks for your input. It is the round cylinder model, which Leonard says is an older engine with a true venturi. And yes, it was a 6v. battery---well, it mighta been something else--it was a loooooong time ago. About 3in square and 5in or so high. It said EVEREADY on the side, as I recall, and had two screw-on terminals.

>Steve: Thanks for your input. It is the round cylinder
>model, which Leonard says is an older engine with a true
>venturi. And yes, it was a 6v. battery about 3in square
>and 5in or so high. It said EVEREADY on the side, as I
>recall, and had two screw-on terminals.

...btw... Eveready also makes a 1.5volt lantern battery of the same size and configuration as the 6 volt one. I bought the 6 volt one by mistake many years ago and zapped several glow plugs before I figured out my mistake. When all else fails read the label.

or hook 4 glow plugs in series...

I now use a "glow driver" and a motorcycle battery.

...or diesel

>The instructions with Magnum ABC engines specify a fuel
>containing 20% or more castor oil for break-in. I would
>break-in all three on Powermaster 10-29 GMA, and using the
>same glowplug...a long idle bar Thunderbolt, Zinger, or K&B. (snip)

Steve

Don't overlook the Fox RC long plugs, either. I know, there are those who love 'em and those who hate 'em. But these are what we used with the FP's and Magnums when we were running them, and Matt has gone back to the Fox RC long in his pipe ship after some bad experiences with Thunderbolts. Maybe it is the set-up, I don't know. But for us, they run equally well and are much longer lasting. We are going to be testing some RO Jett plugs here just to see how they came out, but won't know any results on these for a while.

On fuel, you shouldn't need more than 20-25% oil on that Magnum. Any 20-22% all castor should work find for break in. And we only use 5% nitro as well.

As to glow drivers, based soley on my exciting experience, use one with the ring that has to be pulled up to relaese the glow plug driver. The push-on, pull-off style have a strong proclivity for jumping off and into the prop or through the silkspan on the wing when the engine roars to life. Don't ask how I know this as I'll just go off on a rant about them. Ha

My general thinking on break-in props is use one a size or two smaller than you plan to fly with so that the engine can run at flying speed whilst being plenty rich and well lubed. My recollection of the square batteries is that the ones with screw terminals were 1.5 volts. The ones with two springs for terminals were 6 volts. Wouldn't bet money on it though.

> My recollection of the square batteries is that the ones
>with screw terminals were 1.5 volts. The ones with two
>springs for terminals were 6 volts. Wouldn't bet money on
>it though.
>
>Jim Thomerson

Jim;
You are probably right, likely it was a 1.5 volt. Do they still make 'em, I wonder? Has anyone thought about getting a Radio Shack battery case for 4 D cells, and wiring that up for glow plug lighting? It seems like it would be light and handy, if it could be made to work. I had an old VIVITAR flash power pack, but couldn't figure out how to convert it for model airplanes, and it was big and clunky.