RE: Horizon Hobby Dumps MDS Line?

RE: Horizon Hobby Dumps MDS Line?
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Glow Engines >> RE: Horizon Hobby Dumps MDS Line?

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RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 2:48:18 PM

Boomstriker

Posts: 406
Joined: 1/15/2002
From: New Haven , MO,
Status: offline

Both of mine ran OK on the test stand too, but the stand only simulates level and upright flying. Even an MDS can be tuned for reliable running when fuel pressure is constant.
In a hover or any type of 3D is when a finicky engine is going to have problems because the fuel deliver is subject to gravity and extra G forces affecting it, and this temperamentalness is only compounded as the tank goes from full to empty.

When you get the high needle rich enough to pull from hover at full throttle without overheating and detonating, then they get very rich in the mid and will flame-out if held there very long. Leaning the top anymore puts it in the dangerous lean condition when nose up. The only way to combat this is to lean the low as much as possible to help with the mid.

The only way I could drop-in from any altitude was at a idle, because it would load-up REALLY bad when nose down and with any throttle applied. If not, I had to rev it up every couple seconds on the way down to keep it cleaned out or it was sure to die when I went to add power. This makes landing, slow flybys or any 3D maneuvers very risky.

IMO, using an MDS in an overpowered 3D or funfly is just asking for trouble.

As I've said before, maybe in straight, level and upright flight on an under powered plane where it's near wide open most of the time, maybe you could consider it a reliable engine.
I have never seen anyone using an MDS reliably for 3D or aerobatics, on a heli or for any type of competition. Aside from a few that seem to want them for their collection, I've only seen trouble and disappointment, first hand and on the forums.
If I bought every MDS engine that's been a PITA in someone else's plane and ran on my stand, just think how big MY collection would be.

(in reply to Homebrewer)

Post #: 26

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 3:13:06 PM

Sport_Pilot

Posts: 7727
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline

Boomstriker.
It is possible to make a test stand that is tippable, or even rotate to full inverted. As for as how an engine behaves flying VS on a test stand, this is just how well it is set up. I don't know of anything an OS or Webra has over an MDS in this regard, except for the pumped versions.

(in reply to Boomstriker)

Post #: 27

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 3:21:03 PM

Hobbsy

Posts: 10683
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline

I too disagree with Booms characterization.

_____________________________

"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to Sport_Pilot)

Post #: 28

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 3:36:40 PM

Sport_Pilot

Posts: 7727
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline

quote:

When you get the high needle rich enough to pull from hover at full throttle without overheating and detonating, then they get very rich in the mid and will flame-out if held there very long.

I have not owned an MDS but being of Russian manufacture I would expect and I hear that they are fairly high compression ratio engines. This means low nitro and cold plugs. If you do not use low nitro or cold plugs then I would expect overheating and detonating. Please don't knock engines because of your ignorance!

(in reply to Boomstriker)

Post #: 29

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 3:59:18 PM

DrDeath

Posts: 1551
Joined: 4/14/2003
From: Bethesda, MD, USA
Status: offline

I am not a big advocate of MDS but I do not hate hate them. I had an Extra Easy 2 to learn how to fly on. The engine was the .40 size one. I had troubles initially, but someone suggested going to an idle bar. After that the engine ran reliably. I can't say that the power was outstanding though. I have since replaced that engine with a TT .46.

I say all of this because the engines can be tempramental, but they do run reliably if you do the following.

1) IDLE BAR
2) Break in engine well
3) IDLE BAR

and finally

4) Did I say use an IDLE BAR

Hope this helps

Lee

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(in reply to Sport_Pilot)

Post #: 30

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 8:22:16 PM

changed

Posts: 153
Joined: 12/29/2002
From: dfgd, NB, BANGLADESH
Status: offline

I think I'll mount mine on a plaque and use it for the worst crash award. I just can't see wasting hours of fiddling and gallons of fuel to get it to just run ok. I'd rather be flying with an engine that is made to run! With all the fuel I have run through it I could have paid the extra 40$ and bought a nice engine! Thanks guys for showing me the way.

(in reply to DrDeath)

Post #: 31

RE: Horizon Hobby Dumps MDS Line? - 4/16/2004 8:33:20 PM

Sport_Pilot

Posts: 7727
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline

Squint,
I bet homebrewer runs almost as much fuel through an OS before flying it. Most people at my field don't run but maybe an extra tank or two more than the OS. No complaints except you must use the pinch test, and they get stronger and easier to tune after they have run an hour or so. Homebrewer just likes to bench run. I think he and Hobssy get together and crank up a bunch of engines in a huge circle now and then.

(in reply to changed)

Post #: 32

RE: Horizon Hobby Dumps MDS Line? - 4/17/2004 4:16:44 AM

Hobbsy

Posts: 10683
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline

Well, I'm a minimum break in kinda guy, any engine can be broken in after getting it's set up on the test stand. Homebrewer and I have never run engines together but W8YE and I have on a couple of occassions.

_____________________________

"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to Sport_Pilot)

Post #: 33

RE: Horizon Hobby Dumps MDS Line? - 4/17/2004 4:37:56 AM

wrob

Posts: 152
Joined: 1/30/2004
From: Apple Valley, CA, USA
Status: offline

All this talk about MDS engines makes me think I need to go fly mine

.

(in reply to changed)

Post #: 34

RE: Horizon Hobby Dumps MDS Line? - 4/17/2004 5:17:31 AM

Homebrewer

Posts: 1335
Joined: 12/29/2001
From: Colorado Springs, CO, USA
Status: offline

Nope, I run 1-2 tanks on my OS engines because the CHEAP nickel plated liner is softer and easier to break in.

Too many of you are too impatient and many of you have never had a real ABC engine to deal with before. The advantages of the MDS engine is that it will outlive any OS engine out there. One of my MDS 68s is about 5 years old and has close to 300 hours on it. It is only off about 200-300 rpm from when it was new and still pulls strong.

The advice I gave on the bench break in was intended for folks who may not have a properly setup airplane and the bench breakin would help rule that out.

I personally don't give a rats butt whether the entire world hates the MDS line. The more of you that spread its supposed bad reputation, the cheaper I can buy them from ya all. So, please continue bashing the MDS line so I can stock up on more of their engines for cheap!

Thank you and have a good day.

Andy

PS MDS engines suck......please rid yourself of any you may own before it is too late.

(in reply to wrob)

Post #: 35

RE: Horizon Hobby Dumps MDS Line? - 4/18/2004 5:58:44 AM

Thumper1

Posts: 79
Joined: 5/20/2002
From: Moxee, WA, USA
Status: offline

I had one, a 40. Nothing to write home in the way of power. A couple of guys in our group ran the 1.48. Got lots of practice landing dead stick. Tried REAL hard to unload them. No takers. The engine acquired a reputation for runibility problems and very few were bought recently.
Bill

(in reply to Hobbsy)

Post #: 36

RE: Horizon Hobby Dumps MDS Line? - 4/18/2004 6:17:55 AM

Sport_Pilot

Posts: 7727
Joined: 1/21/2002
From: Acworth, GA, USA
Status: offline

Didn't the 1.48 have some sort of carb problem that was resolved a year or two ago?

(in reply to Thumper1)

Post #: 37

RE: Horizon Hobby Dumps MDS Line? - 4/18/2004 8:53:51 AM

Warjet

Posts: 209
Joined: 1/5/2002
From: El Cajon, CA, USA
Status: offline

Along with the longer than expected break-in running required, the machined carbs MDS made were of inconsistent quality, leaked air around the barrel, causing lean-outs and dead sticks at just the right times. The latest carbs (C2) are much better, and the carb off the 2.18 not only works great, but fits the big ST's, Webra's, and anything that the OS 7D carb fits.

(in reply to Sport_Pilot)

Post #: 38

RE: Horizon Hobby Dumps MDS Line? - 4/18/2004 1:19:09 PM

dennis

Posts: 1292
Joined: 1/7/2002
From: Minersville, PA, USA
Status: offline

quote:

ORIGINAL: Homebrewer

Nope, I run 1-2 tanks on my OS engines because the CHEAP nickel plated liner is softer and easier to break in.

Too many of you are too impatient and many of you have never had a real ABC engine to deal with before. The advantages of the MDS engine is that it will outlive any OS engine out there. One of my MDS 68s is about 5 years old and has close to 300 hours on it. It is only off about 200-300 rpm from when it was new and still pulls strong.

The advice I gave on the bench break in was intended for folks who may not have a properly setup airplane and the bench breakin would help rule that out.

I personally don't give a rats butt whether the entire world hates the MDS line. The more of you that spread its supposed bad reputation, the cheaper I can buy them from ya all. So, please continue bashing the MDS line so I can stock up on more of their engines for cheap!

Thank you and have a good day.

Andy

PS MDS engines suck......please rid yourself of any you may own before it is too late.

I'm not going to comment on MDS one way or the other or OS motors for that matter. However if you want to talk about long lasting motors there are only a few glows that fill that nitche. one is the Fox 35 and the other is the Enya35.Both of these are iron and steel and will /have lasted for 50 years of running. I know I have a few.
Dennis

(in reply to Homebrewer)

Post #: 39

RE: Horizon Hobby Dumps MDS Line? - 4/18/2004 2:24:58 PM

Hobbsy

Posts: 10683
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline

I have accumulated several of the MDS C1 carbs and the clearence around the barrel is the same as any other MFG.s carb, if there ever was a problem with leaking, it was through the pinch bolt assembly which they cured by putting an O ring on the bottom of the carb neck. One of the C1 carbs now resides on my old Webra .91 where it works perfectly, a previous owner had butchered the stock Webra carb.

_____________________________

"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to dennis)

Post #: 40

RE: Horizon Hobby Dumps MDS Line? - 4/19/2004 4:44:55 AM