MDS .48 runing like a top
05-30-2003, 02:46 PM
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MDS .48 runing like a top
The last time I tried to run the MDS .48 it was about 40 degrees out and miserable. Today it's about 65 and beautiful. After about 45 minutes of running it just shy of hot here are the numbers I got with an ACE TachMaster and a GloBee Intellitach. I should also mention that for the first 15 minutes I couldn't get it to transition without quitting or almost quitting. I replaced the stock plug with a Fox GoldPost idle bar, you know the ones that are outdated according to some. End of all transition and shaky idle problems. Along with that came instant backflip starts.
prop----------Graupner 12x5 and TruTurn 2.5 in spinner
fuel Fox 5% nitro with 20% 50/50 lube
glow plug Fox GoldPost idle bar.
ACE Tachmaster II--------11,300 or so, it's analog.
GlowBee Intellitach-------11,340 cycling very slowly from 11,330 to11,350.
It's also like the .68 and 2.18 uncannily smooth. In my opinion the MDS .48 is like the K&B .48 in that it works better with big lumber or in this case Super Nylon.
That's it.
prop----------Graupner 12x5 and TruTurn 2.5 in spinner
fuel Fox 5% nitro with 20% 50/50 lube
glow plug Fox GoldPost idle bar.
ACE Tachmaster II--------11,300 or so, it's analog.
GlowBee Intellitach-------11,340 cycling very slowly from 11,330 to11,350.
It's also like the .68 and 2.18 uncannily smooth. In my opinion the MDS .48 is like the K&B .48 in that it works better with big lumber or in this case Super Nylon.
That's it.
05-31-2003, 10:05 AM
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MDS .48 runing like a top
It's just early and difficult to type before the coffee flows into my fingertips. Sounds like the plug is a big improvement .... do you know what the "stock" plug was (manufacturer)?
05-31-2003, 10:26 AM
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Plug
Bruce, it was a Hangar 9 Super plug, I have the Supers in my MDS 2.18 and .68 and several fourstrokes where they work great, just not in this one. I may try a different Super Plug just to see if it was that particular one. Right on about the coffee.
05-31-2003, 03:43 PM
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Carb
The carb is a C2, the first time I ran it in early spring I tried to run it on the factory settings. This time I used the airpressure on a piece of fuel line until I could hear flowing in the carb method to set both needles. It took more air to say that than to set the needles. They were both a little lean but not much. Once I got the top end right it made a world of difference in the entire throttle range. I used the TruTurn just to have some more rotating mass.
06-11-2003, 03:16 PM
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MDS .48 runing like a top
More good MDS news: A student of mine flew a Hangar 9 Xtra Easy with MDS .40 for 31 minutes last night. That was all in ONE flight, no deadsticks, at the same throttle setting the whole way through. We also had two 20+ minute flights earlier in the evening. One ended deadstick because we ran out of fuel at a higher throttle setting.
06-11-2003, 06:29 PM
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Setting needles
Doug, it's fairly simple, just close both needles gently unitl they stop, then take a new clean piece of fuel line, attach it to the carb and try to blow through it. You shouldn't be able move any air into the carb at idle nor wide open. Next, open the carb fully and slowly open the high speed needle slowly until you hear air entering the carb, then place the carb at the idle position or close to it and slowly open the low speed needle until you hear air moving in the carb again. In the case of the .48 this was a little lean but it started and ran until the priming fuel was gone, I opened the low speed an additional quarter turn and that's where it still is, the high speed is about one half turn rich from where I set it by the air method.
06-14-2003, 01:18 AM
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MDS .48 runing like a top
Hobbsy,
You know the story on my frustration with the .48, and the 2nd new carb seemed to fix my problem. Well, convinced it was fixed, I mounted it, went to fly, and it became temper-mental again, just not to the same degree. I took your advice on the idle bar plug, and viola, a completely different engine. It really makes sense when you think about it. 4 large induction ports, midrange too rich--> shield the plug through midrange.
Here's the problem: When I did get it to run right, with the other plugs, transition was instantaneous, now it's sluggish, but absolutely no sign of stalling. The top end is really shy from what it was before. The LHS didn't have the "Fox GoldPost idle bar" plug, just the one that says "R/C Long", in the red, white and blue blister pack. Any idea if the gold one is hotter/colder?
Did you tach any other props? Now I get 14.3K with a MA 10x6, where before it was 15.5 (crummy transition). These numbers put it less powerful than my Mag .40.
You know the story on my frustration with the .48, and the 2nd new carb seemed to fix my problem. Well, convinced it was fixed, I mounted it, went to fly, and it became temper-mental again, just not to the same degree. I took your advice on the idle bar plug, and viola, a completely different engine. It really makes sense when you think about it. 4 large induction ports, midrange too rich--> shield the plug through midrange.
Here's the problem: When I did get it to run right, with the other plugs, transition was instantaneous, now it's sluggish, but absolutely no sign of stalling. The top end is really shy from what it was before. The LHS didn't have the "Fox GoldPost idle bar" plug, just the one that says "R/C Long", in the red, white and blue blister pack. Any idea if the gold one is hotter/colder?
Did you tach any other props? Now I get 14.3K with a MA 10x6, where before it was 15.5 (crummy transition). These numbers put it less powerful than my Mag .40.
06-14-2003, 02:24 AM
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Props
The first time I tried unsuccessfully to run it I had a 10x6 but couldn't get it to run run enough to bother taching it. I haven't tached it with any other prop yet. It's been so rainy plus we lost our field that I've just been building. I deliberately used the Graupner because it's a little heavy, I will try some others soon.
I don't like engines to run much over 12,000 r's. My Saito .50 turns the very same 12x5 prop at 1,000 rpm less.
I don't like engines to run much over 12,000 r's. My Saito .50 turns the very same 12x5 prop at 1,000 rpm less.
06-14-2003, 12:12 PM
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Idle bar ?
I have the Fox Idle bar plugs in all my two strokes except for my MDS .68 and 2.18, they have the Hangar Nine Super Plug that came in them and run fine. The Fox Idle bar plug also cured a part time midrange quitting problem on my Moki .61 LS. I'm going to try the Fox plugs in the .68 and 2.18 just to see what happens. Now that my interest is peaked. I gots to know.
06-14-2003, 01:23 PM
#16
hobbsy....
....I had just the opposite experience....and chucked all
the idle bars a long time ago....
....recently I pulled the OS .60 FSR out of my Kaos and
put in a bench run only .61 RF motor with a pipe....ran
good, but didn't idle that good....kept dieing out after
landing....never could taxi it back in. Started adjusting
the idle from one end to the other....no help....just kept
dieing....finally pulled the plug....
...yep....a darned idle bar (I got the engine used) stuck in
a Fox Miracle plug....end of problem.
The plugs I use are K&B 1L's, K&B 1S, Fox Miracles, and
OS type F in the 4 strokes....that's it....
....
....never had any luck with the idle bars....go figure
the idle bars a long time ago....
....recently I pulled the OS .60 FSR out of my Kaos and
put in a bench run only .61 RF motor with a pipe....ran
good, but didn't idle that good....kept dieing out after
landing....never could taxi it back in. Started adjusting
the idle from one end to the other....no help....just kept
dieing....finally pulled the plug....
...yep....a darned idle bar (I got the engine used) stuck in
a Fox Miracle plug....end of problem.
The plugs I use are K&B 1L's, K&B 1S, Fox Miracles, and
OS type F in the 4 strokes....that's it....
........never had any luck with the idle bars....go figure
