RE: GMS Engine Tuning Problem
 

Here is a GMS 120 http://www.youtube.com/watch?v=CCEU90swLU8

RE: GMS Engine Tuning Problem
 

...that's what happens when you change the muffler on a perfecrly good engine,
the plane immediatly leans out from lack of fuel pressure and dies out....

....stalls, and KABOOM !!! [X(]

RE: GMS Engine Tuning Problem
 

Did that engine even come up to temp? Mine needs to be run for a good 1-2 minutes before the first flight of the day.


The GMS 1.20's run well, but getting the mid-range right is a bit of a bear because the engine changes a bit in characteristic over time until it is broken in fully.

I kept getting mid range cut-outs and hesitations on mine until I leaned the low end a bit MORE than you would using standard tuning practices, and likewise richened the high end a bit more than usual.

This cured the mid range transition.

You know you have the engine in the right range when the head temp hovers around 300 degrees at full throttle.

Much higher than that and you ARE going to have problems.

Lower than 280 and it's running too rich.

A laser temp guage makes it easy to tune up the GMS engines... w/o one, the instructions and standard tuning proceedures seem to produce mis-tuned engines.

RE: GMS Engine Tuning Problem
 

Hi Wayne,

I have an SC 46 engine on my trainer and it has been behaving exactly as described in this thread. (GMS, SC and Magnum engines all come from the same factory)

I pulled the carb to pieces and the inlet was restricted just as described, and shown in the photo on post # 95. I drilled it out with 1.5 mm drill, cleaned the carb, tuned the engine as per the thread instructions and in flying it today the engine never missed a beat all morning, a different engine all together, you can come into land with confidence that the engine will not stop and will transition smoothly. The exhaust note know has a nice crisp note to it.


Thank you and the other contributors to the thread for the advice on solving this problem, it has saved me from buying a new engine as I ready to bin the SC before the modification, as my instructor and myself had tried everything else suggested and that we could think of.

Cheers

David

RE: GMS Engine Tuning Problem
 

Glad you found the problem with your engine.

SC, ASP, & Magnum come from the same factory

GMS, Tower, & Super Tiger come from the same factory but different from above.

SC & GMS do not come from the same factory.

RE: GMS Engine Tuning Problem
 

Are you sure about the GMS - Super Tigre origination?

GMS and Super Tigre seem to list different addresses, which is why I ask.

RE: GMS Engine Tuning Problem
 

What is GMS's address?

— Mailing Address —
GMS (GME)
1610 INTERSTATE DRIVE
CHAMPAIGN, IL 61822

— Additional Contact Information —
PHONE: 217-398-8970

Super Tiger's address

— Mailing Address —
SuperTigre (SUP)
3002 N. APOLLO DRIVE, SUITE #1
CHAMPAIGN, IL 61822

— Additional Contact Information —
PHONE: 217-398-8970
EMAIL: [email protected]
WORLD WIDE WEB: http://www.supertigre.com/


Notice the phone numbers and zip codes are the same

It's all Hobbico in two different buildings about 1/4mile apart

RE: GMS Engine Tuning Problem
 

Thank you for clarifying the source of the engines. Very happy with the engine now, just have to learn to fly!! ( We have been spending al the flying time trying to tune the engine, which was impossible before your modification)

Cheers

David

RE: GMS Engine Tuning Problem
 

Those are the addresses for the Hobbico complex where they handle sales and support.

Somewhere I had or found the original factory addresses and I recall seeing two different Chinese provinces for the factories.

I believe SuperTigre was originally Italian, and GMS strictly Chinese, but Hobbico acquired distribution rights for both.

RE: GMS Engine Tuning Problem
 

It would be nice to know those companies and the addresses. It's been a big secret on here for some time.

RE: GMS Engine Tuning Problem
 

Hi David,

Whether they came from the same factory or not, it seems as though they had the same problem. I'm glad all the contributors here could help and you got your engine working well.

Fly4Fun,

Wayne Miller

RE: GMS Engine Tuning Problem
 

Here is the GMS (China) web site
http://www.gms-engines.com/english/index1.htm

They also make the Current Tower brand engines

Here's the link for the Three Leaves (Clover) or Sanye Co that makes the Sanye, ASP, SC, & Magnum engines as well as Evolution, Kyohso, and the RCV engines

http://translate.google.com/translat...ial%26hs%3DIZi

RE: GMS Engine Tuning Problem
 

Yeah, that GMS-Tower link is a definite.

I wonder if Tower will not produce some of the other sized engines, so as to avoid competing with O.S.?

I'm still curious about the SuperTigre connection though.


Now why can't I get my GMS .32 that I ordered in early November from Tower, until LATE Feb????? Ugh.

RE: GMS Engine Tuning Problem
 

Please look into [link=http://www.rcuniverse.com/forum/m_6956055/anchors_7000051/mpage_1/key_/anchor/tm.htm#7000051]this thread[/link].


Same problem, solved.

RE: GMS Engine Tuning Problem
 

Lone ranger take a chair seat down & look for another one, because you 'll never get it, GMS engines are history believe me .

RE: GMS Engine Tuning Problem
 

Is the company no more?

And if so then what will Tower be doing for their engines, since GMS manufacturers them?

RE: GMS Engine Tuning Problem
 

great info

RE: GMS Engine Tuning Problem
 

While you cannot get new GMS engines right now, it is a little early to say at this point that they will be forever no more.

It is highly likely that a new marketing company will suddenly spring up to sell the GMS and Super Tiger engines.

RE: GMS Engine Tuning Problem
 

Jim,


If it is the same manufacturer that makes the GMS, the Super Tigre and the Tower engine lines, it might be able to sell more, if it produces all three brand names...

... That is, like Sanye makes ASP. SC, SY, Magnum... But each of them is sold by a different retailer...

In this case, it is Tower/Great Planes that sells (and has exclusivity to) all three brands....


This requires a second look.

RE: GMS Engine Tuning Problem
 

They'll probably eleminate the "Tower" brand and come out with a "GMS 75 ABC" To replace the Tower 75 being as the Tower 75 is much more popular than the GMS 76.

RE: GMS Engine Tuning Problem
 

I contacted Tower about this and they said that this was not true.

The story I got was that SuperTigre, Tower and GMS engines are indeed being produced from the same factory.

They are re-doing their production because of the merger of the two lines.

That coupled with the Chinese new year celebrations along with their hard winter has resulted in unexpected delays in all aspects of production.

Tower says that they are optimistic that they WILL have them re-stocked by the end of February.

They also indicated that all of this also affect their parts for Tower engines as well, so they are anxious to get this fixed.

RE: GMS Engine Tuning Problem
 

Give time to time and you'll find out the true story.

I own a couple GMS and is sad but they'r history.

RE: GMS Engine Tuning Problem
 

Well that's what Tower told me.

There has been nothing to back up the assumptions being made in the other thread where you guys discussed this.

That's not to say that you may not be right, however since SuperTigre, GMS and Tower Hobbies engines are all being produced out of the same plant, and it is unlikely that all three brands are going bye-bye at the same time, either a "consolidation" in in progress or it is as Tower's rep told me.

If it is not the latter, then I'll bet that GMS engines will morph into a bunch of purple headed engines from Tower instead.

I'm still expecting my order though.

RE: GMS Engine Tuning Problem
 

Hi guys any idea where can I buy some parts for a GMS 61 & 47 ? towerhobbies will not sell anymore this engines that's a fact sad but true, they just changed again the date of arrivals again to the end of march isnt that enough sign of the problem thay have with OS Co. ?

If any of you know where can I get this parts or anyone here wants to sell them to me please, let me konw.

I searched in all online stores and nobody have them.

GMS 61 : cylinder liner, piston and piston ring.
GMS 47 : crankcase

Txs.
Rafa

RE: GMS Engine Tuning Problem
 

Wayne, when I bought my K&B .61 Twist it had a muffler very similar to yours except it had a plastic end cap on it. Inside it had a baffle that was held in place by a spring on the bolt. It appeared that the designer intended for the baffle to move rearward to make the expansion chamber larger as the throttle was increased. The spring was not very strong. The upshot was that the washer/baffle was wearing the bolt down and wearing out the hole in the baffle. When I heard it rattling I took a look. I replaced the spring with two pieces of K&S tubing locking the washer/baffle in place about halfway in its travel. Later MECOA upgraded the muffler with one with a metal end cap and a fixed baffle. I bought one for the Twist. My Twister came stock with the worlds loudest tuned pipe, I traded it to a feller in Fla. for the plastic end capped muffler.