crrcboatz

My Feedback: (34)

I have a NIB Newest generaton MDS40 with the new carb and a very good OSMax 60fp I am in need of input on which will put out the most power. I can raise the exhaust timing on both to 160 and put them on pipes if necessary. What about expected rpms/power on both with and without the timing work??

regards Curt

Tired Old Man

My Feedback: (1)

You gotta be kidding, right? Rating box stock engines, a 40 against a 60? For even numbers, the 60 will give almost twice as much power as the 40. If you don't break the MDS in properly, meaning a long break in, the 60 will give 5 times the power.

The point to the break in sentence is that you have to take a lot of time breaking in the MDS. The Russian machine work leaves a lot to be desired, but a long break in will match things up well. Keep it warm, but not really hot. Don't break it in cold!!!

Hobbsy

My Feedback: (102)

Surfer, I guess you've never seen an MDS, their machine work is flawless.

maxtenet

MDS are good, but there is no substitute for cubic inches!

Max

crrcboatz

My Feedback: (34)

My reason for asking this is the 60 is only rated at 1250rpms, where as the 40 is good for 18000 on 20% nitro. I have 22 yrs experience with abc engines so breakin is not an issue.

Also, rpms in high powered marine engines, my experience, is THE issue. I have seen .40 engines turning 20-25000 rpms run circles around something turning 12500 or so 60 or 80 motors. So, cubic inches is NOT a complete measure of power.

I have a cmb 45 right now that if I put a prop on it would easily out perform any 60-75 aero motor.

What I am trying to decide is which one to put in a scale crackerbox that is 38 inches long. I have marine heads for both motors, but no experience with either motor.

I would agree bigger cubes equal bigger prop but not speed necessarily because of rpms and weight being a factor. If I put say that cmb in the boat it would be far too hard to keep on the water. So put something with less power ie one of these motors in it and get something easier to handle and better idle for fun factor.

Anyway, input still needed.

Regards Curt

dennis

My Feedback: (90)

Curt, The OS60FP was by any definition a sport 60 motor aimed at the beginner and casual flyer. It was heavy and does vibrate a little and being a plain bearing mildly timed motor might seriously dissapoint you. A pipe is not a reciepe for long life for this motor as I'm certain that it won't stand up to the increased rpm and pressure too long.
As to the MDS I can't comment save to say that there is quite a bit of controversy on the quality of these motors. My limited experience has been that given an hours break in with 5% nitro or less fuel with 20% oil at a fat 2 cycle they generally will break in acceptably and perform well with no problems. If yours is an earlier one you might have a leaky carb or one that needs the carb base sealed better then stock.
Bottom line is that I'm not advocating a pipe for either of these motors as there are better candidates for higher output then these. Rossi,Jett, Nelson, are equivelant to the CMB's that you use and would certainly live up to your expectations. Dennis

proptop

My Feedback: (8)

I also have both engines...I'd say go with the MDS .40...It at least looks like the ports are big enough to support high(er) R.P.M. breathing if you decide to try a pipe. I agree about the FP .60 in that it's a "torquer" not a "revver". It's a "long stroke" or "under-square" design, and likes a big prop, and w/ the small carb. ya can't really expect too much from it except a good reliable sport engine. Maybe that's what you want though? Flip a coin?

Waldopepperaxel

Howdy, a friend of mine just bought anold trainer plane hanging on the ceiling it came with an OS 60 FP, this motor was working great,,,, I'm talking 1 flip she's running it was put on a 40 sized trainer and cooks this plane along no problem.

The problem......... My friend,, very new to the hobby,,, 3rd week,,,decided to clean his motor after a dead stick landing into the high weeds and had tangled a bit with some dirt and grass nothing major, but as he was cleaning,,, he touched the forbidden factory air screw, when the engine wasn't running like he remembered, My fault really, everyone I train the very first ting I tell them is to never touch that air screw, his motor was running awesome right from the first time out with it, so I never mentioned it thinking he wouldn't touch anything with out me being there,,, I was wrong... we have no manual and I'm sure now that I know he turned it, we can get it figured out, but it would be a little quicker if someone knew the settings for this screw, Fully closed,, a half turn out ?? 1 1/2 turns out?? anyone with a little info on this would be very helpful...

Waldopepperaxel

Howdy, a friend of mine just bought anold trainer plane hanging on the ceiling it came with an OS 60 FP, this motor was working great,,,, I'm talking 1 flip she's running, it was put on a 40 sized trainer and cooks this plane along no problem.

The problem......... My friend,, very new to the hobby,,, 3rd week,,,decided to clean his motor after a dead stick landing into the high weeds and had tangled a bit with some dirt and grass, nothing major, but as he was cleaning,,, he touched the forbidden factory air screw, when the engine wasn't running like he remembered, My fault really, everyone I train the very first thing I tell them is to never touch that air screw, his motor was running awesome right from the first time out with it, so I never mentioned it,, thinking he wouldn't touch anything with out me being there,,, I was wrong... we have no manual and I'm sure now that I know he turned it, we can get it figured out, but it would be a little quicker if someone knew the settings for this screw, Fully closed,, a half turn out ?? 1 1/2 turns out?? anyone with a little info on this would be very helpful...

EyeflyRC

My Feedback: (147)

Set the air screw half- way in the air hole for the beginning point. Tune for good transition from that point. Out for leaner, in for richer.

NM2K

My Feedback: (14)

There is no magic setting. Adjust it until it runs right. If you adjust it back and forth across its excursion and it still isn't right some place along the line, start looking for a loose carb, loose backplate, loose cylinder head or a piece of debris in the spray bar.

Some of the OS airbleed carbs that I used in the Seventies for training the wife to fly used to run best with the screw completely out and residing in the tool box. It depended upon the weather, prop size, state of break-in and type of fuel that we were using that weekend. I'm not saying that yours will run best when completely removed, just that there is usually a lot of flexibility.

Try changing the glow plug if the engine continues to be persnickety. Glow plugs can go bad without burning out completely. Good luck.

bla bla

MDS are internationally known as just about the worst engines availble!
The importers/distributors have a x10 mark up on the in-price... thats why they're so keen to flog them to the average punter.
You're being cheated, not to mention brain washed.

RCVFR

My Feedback: (7)

Worst engines available? Gosh, I didn't know that. I have a MDS 40 that runs like a champ, I have a 48 I have been flying on a Twist for 2 years, I had a 1.48 that was a powerhouse after I changed the carb (I sold it to a friend). Somehow, I don't feel cheated. But tell me about the brain washing; did it hurt?

bla bla

And you where happy? This is the brain washing I refered to .

EyeflyRC

My Feedback: (147)

I recently acquired two MDS .48 engines that looked near new with little running time from two modelers who could not get them to run reliably. The price was right so I though I would give them a try. I have a lifetime of experience with a wide variety of glow engines and never met an engine I did not like. First I researched problems people have had with MDS and their recommendations. I then bench ran both engines on a test stand and after tuning the carbs, had both running fine with a good idle, great transition and good power. Hand starts both hot and cold were a couple of flips by hand with my starting stick. After running a couple of tanks on the bench, I thought they were ready to be mounted in a plane for a prolonged break-in.

I mounted the first engine in an Eidecker 40 trainer at the 10 O'clock position and went to the flying field. My plan was to put some running time on the engine to break it in properly. I set the high speed needle slightly on the rich side and took off. Pretty soon I found that after a while the engine would lean out a bit in the air and slow down unless I quickly reduced the speed to keep it running. To make a long story short, I had twelve flights averaging about 14 minutes each (a total of two hours and 48 minutes over two days). I made small adjustments to both the LS needle and the HS needle to get the engine to perform better, never running it too lean. By the end of the twelth flight, the engine was running better but was still not what I would consider reliable. I had to set it off a bit rich and it would lean out in flight. Often, if I stressed the engine with some mild aerobatics, the engine would start to die and I had to slow it down to keep it running. In no way could I consider it to be reliable or broken-in yet.

My conclusion is that this MDS engine is not user friendly and it takes more experience and patience to operate than most modelers would give it. In no way would I recommend the engine to a non-expert modeler. It requires tedious tuning, a very long run-in and in my case, the results have not yet been worth the trouble.

Here is what I had to do to get a modicum of performance from the engine without flame-outs. First of all, the engine has the new C-2 carb and it is sealed well and does not leak air even when hot. I used a Fox shielded plug, my own mix fuel with no nitro and 21% all castor oil. a 11/6 Master Airscrew prop, Davis strap-on pitts muffler with one exhaust tube. In the air, I always had good transition but high speed sounded like a four cycle at the beginning of the flight, it would smooth out after about five minutes but towards the end of the flight, it would want to die if stressed unless I immediately lowered speed. Engine was mounted without cowling to be completely exposed to cooling air.

I then mounted my second MDS .48 in the same plane. This time with the original MDS muffler. This engine also had the original carb. The characteristics of this engine were different from the first. I could get a reliable idle and transition on the ground but it would not transition well in the air and often flamed out on transition. High speed was much better than the first. It ran faster and with a much clearer sound and did not lean out as much during the flight. Intermediate speeds were very rough in the air but smooth on the ground.

I switched to the C-2 carb from the first engine and it helped reduce flame-outs in transition but intermediate speeds were still rough and unreliable. I only have five fligthts on the second engine averaging 13 minutes each for total engine running time of one hour. So far I am not seeing any improvement in transition while in the air. On the ground, it transitions fine. It probably needs more break-in time.

I am not yet giving up on these MDS engines, but I must admit that so far I have found them to be troublesome and extremely sensitive to carburator adjustments. The high speed needle is affected by any change in the low speed needle and very little movement makes a large difference. Next I may try a Perry carb to see if it helps. May also try a Perry oscillating pump. Most of all I will say that this is most certainly not a beginner's engine nor one for those who are experienced but short on fiddling time. Eventually, I am sure I will get them to run better, but I am not at all certain that it will be worth the trouble. So far, I am only doing it for the challenge.

Marcol

I'm with you on this one. IF you get a good one they are reasonable to a point. BUT if you get one of the other 99 bad ones they are absolutely the most frustrating engine you will ever have.
As one of our club instructors I have personally had experience of dozens of these motors when a newcomer turns up at the field. Most of the problems stem from the bad carb design and especially the o rings in and on the carb. It's not good to tell a young lad that the motor that the model shop has sold him is a dog, and should be used as a fishing weight!!
Funny though I've never had to tell anyone the same story about their O.S. or Irvine.

Colin

EyeflyRC

My Feedback: (147)

To continue my experience with the second MDS .48, I now have forty-two flights with the engine mounted in my Eindecker, average flight time has been 13.7 minutes each, with total engine operating time of nine hours and 36 minutes. I am using a Fox shielded glow plug, Master Airscrew 11/6 prop and my home mix no nitro 10% synthetic, 11% castor oil fuel. The engine has finally come into its own. It starts with a single backflip after prime, idles reliably, transitions well, and screams at full speed. The engine has excellent compression and shows no sign of wear at this time. While I would not recommend the MDS .48 for a newby, in the hands of an experienced modeler who has the patience to break it in right, it is a fine engine. Perhaps I found a good example, but I am happy to buy any MDS engine at the rock bottom prices at which they are now selling. So far, I have bought four (4) MDS .48's and two (2) MDS 148's and like each one of them for sport flying.