Thunder Tiger Pro .25

They are big aren't they and 9-10" props are huge!!! I have no mounts for my Fox .35's maybe I should cut one like you before I mount it up on the Ring.

Glad it went well for you.

Ron

I'll make a video of it tomorrow. I'm going to try it on a bladder too. The needle is fairly fine, it might work. I'd never get a 4-2-4 for pattern flying like that, but hell, I'll just have to fly it wild like I do the little ones.
I wonder if it's normal for it to have to warm up before I can remove the glow clip. Like I said, maybe i just got the plug too wet cranking. I might have over-primed it. Back flipping works well. Front flipping does not work so well.

I just cut a notch out of a board and drilled screw holes in it. I used 4-40 screws and blind nuts and added lock nuts on the bottom. I have a 4 ounce clunk tank behind it.

I definitely see some remote NVs in my future for all of my planes. Not just to save my fingers, but to preserve my needles too.

Hi Rusty,

Good to see it made it and your having fun with it. I wish I had known you still needed a tank for it i could a sent you one. I wouldn't bother with a bladder tank, you might check the distance on fuselage and maybe look at a plastic R/C type tank alot of people use them and many set them up as a 'uniflow' tank, at least i'd used muffler pressure. I'd try a fresh plug and maybe pull head (use star pattern to re-torque) and see if someone slipped a second gasket on it, its been so long i don't remember.

Remember the RPM specs are highest usable RPM, you don't want to be to running at that high of RPM unless your racing, and race engines don't live real long.

Hey Mark, yeah it runs nice. I'll have more time to play with it tomorrow, and rig something up for a tank. I can always use a party balloon inside of some sort of container. I've conjured up some pretty funny looking ones that work fine.

Yea, the big ones need to heat up some before you pull the glow driver off. Doesn't take too long though, 30-45 seconds, less for later runs. You can consider refueling an open vented tank before flying even, but remember these bigger airplanes can get heavy on the arm after a while, especially if they have a lot of nose out between the rudder and motor shims so you don't want them up too long.

One nice thing about the bigger engines is you can set them once, and frequently not have to adjust the needle again that day, or longer!

Phil

Removing the glow driver when the engine is running should not cause it to stop, increase speed or decrease speed.

It could be that the plug is on the way out ie about to die or more likely an issue with the heat range or amount of nitro in your fuel or just plain old too rich. The more nitro, the cooler the plug needs to be, the less nitro, the hotter the plug needs to be.

So I would suggest, 1 try another plug. 2 make sure you aren't using more than 10 % nitro, 3 check what type plug you have and possibly try more appropriate plug, 4 tune the engine properly, ie adjust needle til it peaks then back off slightly.

Cheers

Thanks for the detailed answer, Warren.
I'll order some proper fuel. I have no idea how much of the volatiles are still in this old jug, as it was given to me. The bottle was so stained, I threw it away and washed out an old Glowplugboy bottle and put it back in that after I filtered it. I'll look at Merlin and see if they have the plugs I need, and get a couple of different heat ranges. I know it will use an OS plug.

Phil, that sounds about right. When I put the clip back on to check if the speed changed(and it didn't), it had been running for about a minute.

My shoulders are precarious at best, so we'll see how I do with the harder pull from the big boy.

the pull will be fine, you'll love it, it will feel like your flying a airplane...

Also remember the squeeze test on fuel line, once the needle is set, give the fuel line a quick pinch, if RPM goes up your good, if RPM dies down your too lean.

I just came in from playing with it. Watch out, the dang thing spits like a cobra! I walked away from it after hooking up the fuel, which was slightly elevated. I forgot to clamp it, so the whole time I was messing around, the crankcase was filling up. I came back and hooked up the glow driver and gave the prop a whack and it belched fuel spray and smoke out of the venturi, covering my glasses, face and shirt. I clamped the line and kept flipping and it kept regurgitating all over me. after about 15 trys it started running backwards and spraying everywhere, and finally caught and spun up. I unclipped it and it kept running, but it still took a while to burn off the flood.

I put one of those new narrow GF3 Master Airscrews, a 9x4 on it and it spun up into the high 16s. I think Ken is right about those being nothing but air beaters. I was leaning it out an got scared of overheating it and backed off. It seemed like it got pretty hot, but I let it cool and ran it again and it seemed okay. That's obviously not enough prop for it so I'll give it a bigger load next time.

I had trouble with it cutting off a few times at first and realized the fuel was foaming, so I set the tank on a wadded rag and it ran fine. It was still vibrating so I quit for now. I need to make a hardwood or at least a plywood mount instead of a 1x6 pine plank clamped to a plastic sawhorse. It just ain't doing the job, and the bolts were coming loose.

Reading a thread at Stunthangar re-enforced what some of you told me earlier, that 4-2 really isn't necessary with modern engines. When I get all this to the flying field, I'll start by launching with a rich 2 stroke, see if it unloads and finds a happy place in the air and it should do the job. I'll have to try different props and figure it out for myself. I wanted to make a video, but it started raining, the motor mount was failing, and so I quit until I can get it mounted properly.

better to go higher pitch for first flight and have it go too fast, then to have it fly slow with no line tension, launch at rich two cycle.

Mark Boesen wrote:better to go higher pitch for first flight and have it go too fast, then to have it fly slow with no line tension, launch at rich two cycle.

Yeah, I think I'll start with that APC 9x6 you sent me.

I'm going to see about fixing the Shoestring wing tonight. The hardest part is carving a 3" piece of 1"x.75" tapered lead edge tip that needs replacing. The HS didn't have any 1" square dowels or LE stock, so I'm going to cut it out of a 2x2x8 block of medium balsa that I bought about a year ago to make a Little Devil fuse.

I wanted to check the glow plug to see what this type looks like, and to see what sorts of combustion clues it showed. I hooked up the glow driver and it wouldn't light. I tried a couple of Cox plugs and they lit plenty well enough for my mediocre batteries. So I need to order some, which leads me here for advice from our panel of experts. I suppose it's a hot plug and it has an idle bar. I wanted to ask if I needed an idle bar for a CL engine, and if there are any preferences among the recommended replacements in the manual.

The coil looked normal before I messed it up poking and prodding, but the ohm meter read an open circuit. First I used sandpaper to clean some of the black smut off of the idle bar, it was completely black, which makes me worry if I had mistreated the engine. Could I have ruined it by running too lean while I was experimenting with needle settings yesterday? Anyway, here's what it looks like:




The manual says to use a hot R/C long-type plug such as K&B or O.S. No. 8. I'll be using 10% nitro fuel and of course not throttling. Should I get a plug without a bar? And I suppose hot or medium for the 10% fuel? I'll check various places, starting with Merlin, and give my HS a call too. It would be nice if they had some.

Thanks for any insight,
Rusty

Yes I'd be putting in an OS No 8 if I were you.

warrenlead wrote:Yes I'd be putting in an OS No 8 if I were you.

Looks like the Merlin 2002HD is their OS#8 equivalent and has no idle bar. Is that as good, or should I spend a couple more bucks and get the name brand OS #8?

The Idle bar plug is an RC plug, so the engine doesnt cut out at low rpm. ie idle. Some of the Stunt flyers use them in control line aerobatics so they dont get a flame out in maneuvers, as they run their engines rich to get a 4-2-4 break.

I dont think it's necessary for a 25, considering you will be running a wet 2 cycle anyways.

Anything like an OS No8 or A4 should work fine. You might need to try a few different plugs to see which works best with that engine.

BTW it sounds like your idle bar plug is intermittent so needs changing anyway.

Cheers

Pine 1x3 is dicey as a test mount. I use them, but I have a steel table (actually the frame of a household trash compactor) I use to clamp everything down to, so it works OK. I am really considering one of those nice adjustable aluminum test mounts.

Idle bars retain heat, if it ain't broke....then again, can you get better by swapping a simple item? Hotter is equivalent to advancing timing, cooler is equivalent to retarding timing. You really need to buy at least one of each if you are going for better than "good enough" (this stuff still confuses me)

If you are running rich you will develop more heavy varnish than if you are running lean.

Phil

cribbs74 wrote:They are big aren't they and 9-10" props are huge!!! I have no mounts for my Fox .35's maybe I should cut one like you before I mount it up on the Ring.

Glad it went well for you.

Ron

I went the other way. Always flew .40s, then was introduced to a .15, an .049, .020 and then finally the .010. A lot of fun.

Looks like #8s are plentiful. I can even get one in Columbia for $9.99. Or I can pay shipping from Merlin cheaper than that. Thanks for the info, dudes. It's probably best for me that the engine is down for now. I got some work done on the Shoestring airframe tonight. Does everyone agree that Merlin's version of the OS8 is just as good as the OS brand? They have the best price.

I think Warrens got it pretty well pegged...plugs for this set up are not gonna be real critical, you don't need a really hot plug, also a idle bar or no idle bar shouldn't make a big difference as your gonna run a fairly rich two cycle, OS plugs are great, great price, but great. I think that was a run of the mill Fox R/C long in it.

Great engines Rusty my TT 46pro is still beating up the strip
Outside Ankara.
I know this maybe controversial but.. I've never come across
An idle bar plug that worked well when ever a newbie turns up
With his own plane if it has a bar type plug we chuck it away.
That motor demands either an OS 8 or Enya 3.
I can't help think ideally you'd run a 9x5 on her.
My .46 was in an ARC Jupiter and it didn't like the rec 10 7
But loved a 10x6.
Flooding/normally I'd take the plug out, stick a rag over the
Hole and use the electric finger to clear.
Some of our guys use the lower tech point nose skywards
And hand turn the prop to drip fuel from exhaust but
A little difficult when it's strapped to a bench I guess.
Finally I think you're getting to the stage where an electric
Starter is something you should be considering.
I've seen many things over the years just last summer
a pal had his 46la burst into life when he connected the glow
On a hot day.
If he'd been a flipper his fingers may have been within the
propeller arc.
Me and my Cox's are the only things at our club not using
A starter. It's one thing to get a nip from a 5 inch Cox prop
But as they get bigger the pain co efficient goes up
Exponentially.
I know there are those among us who shun new technology
And imagine some sort of romantisim attached to flip starting
To those I say "imagine trying to pick your nose with
No index finger......."

The idle bar plugs are for cross-scavenged engines, no need for those on a modern engine. OS#8 or Enya#3 should work fine, can't say anything about the Merlins other than that my have no markings on them and are impossible to tell appart from each other...

Try a 9x4 prop instead and let the engine rev a little, it is a modern design and a too large prop will just lug them down and they overheat.

Maybe I loosened the element trying to burn off the flood like I would with a Cox or a Norvel, the only other engines I have experience with. I was worried about the possibility of my having mistreated the engine, but although the plug(not the element) was black, there was no sign of trauma to the piston or liner. It's all wet with clean castor, the piston is shiny and new looking, and the liner has no discoloration or marks except a mottled nickle color, which I think is probably normal.

It looks like OS 8 plugs are everywhere, so I plan to buy one tomorrow. I'll be extra careful with it until I can get a spare. This engine feels like it has very high compression. I see there is no head gasket or shims, I assume that's the way it's supposed to be.

I have 9x4, 9x6, and 10x4 props. I'll be trying them all. The engine's future airframe is coming along, so hopefully I'll be trying out the TT soon.

We'll have to start calling you Popeye Rusty and if you want to take up arm wrestling
I'll be your manager.


Looking forwards to the vid as always.