SuperTigre GS-40 break-in

SuperTigre GS-40 break-in
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SuperTigre GS-40 break-in - 9/18/2007 9:48:59 PM

DonStegall

Posts: 617
Joined: 8/8/2005
From: Monroe, NC, USA
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I've got to get a SuperTigre GS-40 for some performance testing for Club 40 Racing

I haven't broken a ringed two stroke engine since the K&B Torpedo engines of the 70's.

I normally use Omega 15% with 4 ounces of castor added to bring it up to 20% oil. Will that do for this engine?

I use a PSP Mfg test stand for most all of my break-in operations and testing.

What is the best procedure for the first few minutes, and then the next half hour to hour of running time?

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Don Stegall
RCPRO - http://www.rcpro.org - http://www.rcpylon.com

Post #: 1

RE: SuperTigre GS-40 break-in - 9/19/2007 12:49:39 AM

Jezmo

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From: Spring, TX, USA
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I don't add any castor to mine. I break them in on "As manufactured" Omega 15% running just lean of the break between two and four stroke for a full 8 oz tank. Then I fly it running 200 rpm's rich of peak. I also switch to Cool Power 15% with 2 oz of Castor added to each gallon after the first couple of tanks. It will continue to get stronger as the ring seats but more oil or rich running doesn't seem to help with that. Some seem to break in faster than others and I just always assumed the ring in those didn't get distorted as much when assembled at the factory. I have never had a rod big end problem doing it this way and I have run in at least 5 of them in the last couple of years as well as some of the older ones from Italy years ago. In my eyes it's the best bang for the buck around with the TT 40 Pro a very close second.

I just got my LA Racer and I will be comparing my ST GS40 with my TT 40 Pro on it. (Fixing to try some Club 40) Let us know how your tests go.

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Raptor 50 V2 OS 50 Hyper, T-Rex 450XL CDE, Spektrum DX7, SuperTigre OS FOX Saito Enya Jett TT

(in reply to DonStegall)

Post #: 2

RE: SuperTigre GS-40 break-in - 9/19/2007 2:04:59 PM

DonStegall

Posts: 617
Joined: 8/8/2005
From: Monroe, NC, USA
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You'll have a blast with Club 40. The great thing is that the planes make fun everyday sport planes, and they do well on a pylon course as well. One thing I have found is that I really like to use some exponential on the control surfaces so that the plane is not twitchy. I have occaisionally forgotten to add it on a setup and the first flight is ... shall we say, entertaining.

What I'm up to is testing for the Novice/Bronze class. With the O.S. 40 LA apparently being discontinued, we need a good low cost solution for the entry level class. Chuck Waller had recommended that we try using the ST GS-40 with a larger diameter, low pitch prop like an APC 11x4 to keep the speed down. So I'm going to give that a try.

I think it may work because I've been testing a variety of engines on Club 40 planes. A lot of guys around here did not want to buy .40 engines. So I stuck a brand new, but broken in, O.S. .46 AX on a SRM2. With an APC 10x6 on it, it has a 5-10 mph advantage over the best TT Pro 40 I have. So I tried putting an AP 11x4 on the 46 AX and it brought it down to about the same speed as the TT Pro 40 planes prop'd for maximum speed. Some of the .46 guys around here have been using the APC 12.25x3.75 Stunt prop and you can actually torque roll a Sky Raider with that setup.

_____________________________

Don Stegall
RCPRO - http://www.rcpro.org - http://www.rcpylon.com

(in reply to Jezmo)

Post #: 3

RE: SuperTigre GS-40 break-in - 9/19/2007 3:05:33 PM

Hossfly

Posts: 3770
Joined: 12/3/2001
From: New Caney, TX, USA
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quote:

ORIGINAL: DonStegall

I've got to get a SuperTigre GS-40 for some performance testing for Club 40 Racing

I haven't broken a ringed two stroke engine since the K&B Torpedo engines of the 70's.

I normally use Omega 15% with 4 ounces of castor added to bring it up to 20% oil. Will that do for this engine?

//snip//

One thing about the current ST 40s that Great 'Panes' just refuses to correct is the absence of the carb. insert that came with the .40 engines when under World Engines, and was later installed in the Como series of engines which made them heads and shoulders more user-friendly than the ST from GP.

I am a ST fan since CL combat days back in '61 when the first ST 35s appeared. Talk about something to Break-In, wow that was a finger buster for the first couple hours.

That problem with the idle set-up makes the ST .40 a bummer among the rank and file RCer. All because of the idle problem. I make inserts out of brass tubing which work very well for those friends that want them. While one may lose 5-800 top end RPM with a sport prop, the increased reliability is almost unbelievable.

This engine should be the love of the Club 40 crowd if the rule-makers allow the insert, and the users can tolerate reliability over that last several hundred or so RPM.

I plan on finding out at the race at Scobee field on 9/29. Been a long time since I raced. Looking forward to a relaxed kind of racing.

_____________________________

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AMA Life L-93, Leader and CD for 45 years
Official Candidate: AMA Ex. Vice Pres. Vote H. Cain. Help move AMA into 21st Century
The only source of knowledge is experience. Albert Einstein

(in reply to DonStegall)

Post #: 4

RE: SuperTigre GS-40 break-in - 9/19/2007 3:15:55 PM

fizzwater2

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Joined: 8/16/2004
From: Paola, KS, USA
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what insert are you referring to? I have an older GS40 ringed and don't remember any insert..

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Post #: 5

RE: SuperTigre GS-40 break-in - 9/19/2007 5:50:12 PM

Jezmo

Posts: 807
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From: Spring, TX, USA
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I have never had an insert in a GS40 either although I do remember them being in the Como's. Kinda makes me wonder if the Carb from a Coma got stuck on at the factory when the supply ran low on ST carbs. I have put the cut down spray bar from the larger 60-90 engines in the 40 and picked up some more power without any loss of idle reliability. I don't doubt that some GS40's have idle/transition issues but I have never owned one that did and after showing some of the guys at our field how to tune the ST carbs they absolutely love them. They really are good carbs, it just takes some know how to make them work. They are not very "newbie friendly" I guess is one way to put it.

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Post #: 6

RE: SuperTigre GS-40 break-in - 9/19/2007 6:16:16 PM

Jezmo

Posts: 807
Joined: 6/26/2006
From: Spring, TX, USA
Status: offline

quote:

ORIGINAL: DonStegall

You'll have a blast with Club 40. The great thing is that the planes make fun everyday sport planes, and they do well on a pylon course as well. One thing I have found is that I really like to use some exponential on the control surfaces so that the plane is not twitchy. I have occaisionally forgotten to add it on a setup and the first flight is ... shall we say, entertaining.

What I'm up to is testing for the Novice/Bronze class. With the O.S. 40 LA apparently being discontinued, we need a good low cost solution for the entry level class. Chuck Waller had recommended that we try using the ST GS-40 with a larger diameter, low pitch prop like an APC 11x4 to keep the speed down. So I'm going to give that a try.

I think it may work because I've been testing a variety of engines on Club 40 planes. A lot of guys around here did not want to buy .40 engines. So I stuck a brand new, but broken in, O.S. .46 AX on a SRM2. With an APC 10x6 on it, it has a 5-10 mph advantage over the best TT Pro 40 I have. So I tried putting an AP 11x4 on the 46 AX and it brought it down to about the same speed as the TT Pro 40 planes prop'd for maximum speed. Some of the .46 guys around here have been using the APC 12.25x3.75 Stunt prop and you can actually torque roll a Sky Raider with that setup.

At 49.95 it is a great entry level engine and since it is a ring motor they are virtually indestructable. Lean runs don't hurt them at all like they do with other types. They will outlast any bushing/ABN engine and that should be important for keeping the costs low. The one thing I don't like about the ST is the muffler. I would like to see them allow the Tower muff as it is only 15 bucks and doesn't add appreciably to the power. It does hold up much better than the stock one does and it is lighter which helps with model balance. (Mine all seem to come out nose heavy with that big ST muffler up there.) The most I gain switching from the stock ST to the Tower is about 100 rpm's. It adds much more to my other engines sometimes as much as 5 to 800 more r's but not on the GS40. I guess that ST muffler is sized for the GS40.

Taking some pitch out while adding diameter should slow them up a lot. Some experimenting like you are doing will show the correct relationship of pitch to dia. to get them back to where the LA's are now.

I haven't raced in many years but this seems like it will be a lot of fun. (At my age 428 would be more like work not fun) Have a great one and I hope your results are positive.

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(in reply to DonStegall)

Post #: 7

RE: SuperTigre GS-40 break-in - 9/20/2007 3:28:09 AM

Hossfly

Posts: 3770
Joined: 12/3/2001
From: New Caney, TX, USA
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quote:

ORIGINAL: Jezmo

I have never had an insert in a GS40 either although I do remember them being in the Como's. Kinda makes me wonder if the Carb from a Coma got stuck on at the factory when the supply ran low on ST carbs. I have put the cut down spray bar from the larger 60-90 engines in the 40 and picked up some more power without any loss of idle reliability. I don't doubt that some GS40's have idle/transition issues but I have never owned one that did and after showing some of the guys at our field how to tune the ST carbs they absolutely love them. They really are good carbs, it just takes some know how to make them work. They are not very "newbie friendly" I guess is one way to put it.

I don't even remember all the #s for the ST 40 engines. The ST 40 was around long before the Como came on the market, about '86 or so. Almost all those ST 40s I flew were round head, and I believe 6 head bolt models just like the Como engines when they appeared. The carbs were idntical so it mattered not whether ST or Como. Incidentally it was a Como I flew today as I still have another NIB Como 40 along with some Como .61s and a couple .90s NIB.
My inserted Como 40 using APC 10-5, racer, and buddie NJ with his TT 40 pro using 10-6 were just about neck and neck, although he may have been a tiny tad faster. I carry a big 1800 mah battery so I am a bit heavier.

Did you participate a few years ago when the 4-Star 40 racing thing was going here in the Houston area? Maybe you were tuning those "STOCK" ST 40s that were turning a 9-7 at 18,000 + RPM. Man those guys were some kind of "engine tuners"!

I also used those 60-90 spray bars until those "tuners" got that outlawed. However I didn't have to idle back then.

I will hand it to you, if you can ensure no spitting and sputtering on a ST 40 when going from idle to full throttle, all the time, you are definitely the man of the ST hour. 45 and 51 are no problem but the .40 gets me goat as every time I think I have it fixed, bam, it bites my butt. Hence the insert which solves all the problems.

_____________________________

Horrace Cain.
AMA Life L-93, Leader and CD for 45 years
Official Candidate: AMA Ex. Vice Pres. Vote H. Cain. Help move AMA into 21st Century
The only source of knowledge is experience. Albert Einstein

(in reply to Jezmo)

Post #: 8

RE: SuperTigre GS-40 break-in - 9/20/2007 4:16:20 PM

Jezmo

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From: Spring, TX, USA
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All of my round head ST's were 45's. The 51's have given me the most problems although only the newest ones from China. I had an older one made in Italy that ran absolutely flawless. I read in somewhere another thread that all of the 51's now use the CL porting which explains why they turn 12X6 props so well. It's strange how the GS40's are giving you fits. After the the first tank I usually don't have to move the low needle nor the spray bar any more, only the high speed needle when changing fuel types/brands or if the weather changes significantly.

I didn't race when the four star stuff was popular but I did help some friends with their GS40's. I have always thought that for an inexpensive sport engine they were the best and most powerful. I like the saying, if it's ABx it is either wearing in and getting faster or it is wearing out.

On another note I work with a guy that I have been friends with for almost 20 yrs that goes by hossflyrick online. Yours is only the second time I have seen that used. Maybe I 'll see you at Scobie next weeend.

P.S. Your signature line is great. I wish more people understood and believed in that quote.

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Post #: 9

RE: SuperTigre GS-40 break-in - 9/21/2007 6:27:40 PM

stanlattrell

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From: Leander, TX, USA
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I've been running ST engines and tuning their carbs since the late 60's and have found them to be more sensitive to tune on the low end due to the idle needle being so blunt. An eighth of a turn is a large adjustment, and may take you past the sweet spot. When close to right, moving the adjustment so you can just barely see the screw slot move is more in line with what it takes to get them right. The top end needle should be set at a rich 2-cycle first, and then do the adjustments on the low end, occasionally checking to see that the top end is still where it should be. I realize I may be giving advice to folks with more and better experience than I have -- another opinion may be helpful to someone having trouble........

The ringed engines need to have AT LEAST 5 tanks of 6 - 8 oz. each before you even try to set the low end -- the ring has to partially seat and the engine has to loosen up some before the low end will react right, allowing you to tell which way to adjust. As an aside, I have recently broken in and set the carbs on 2 ST GS 40's for Club 40 Racing, and I found the idle needle on BOTH these carbs were set more than a full turn rich as they came from the factory. For someone not familiar with ST carbs, this could really twist your tail..........

Another issue that can make them difficult to nearly impossible to tune correctly is an air leak around the carb throat -- if there is any question, use some sort of a sealer when installing and tightening the carb in the engine throat. This makes many problems go away...

Stan

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Post #: 10

RE: SuperTigre GS-40 break-in - 9/21/2007 8:28:57 PM

DonStegall

Posts: 617
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From: Monroe, NC, USA
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Thanks to all for the information. I'm glad I posted requesting help before hand, as I'm sure the advice has saved me a lot of time. And I'm glad that you guys are willing to share. Thanks again.

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RCPRO - http://www.rcpro.org - http://www.rcpylon.com

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Post #: 11

RE: SuperTigre GS-40 break-in - 9/22/2007 4:50:12 AM

Jezmo

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From: Spring, TX, USA
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Stan you are right on the money. Only thing I have found a slight difference with is the run time befoe the ring seats. My last 51 took almost 2 gallons however none of my 40's took more than two tanks before they would idle well. I wonder if there is some inconsistancy in the assembly that causes some of the rings to distort just a smidge and require more time before they seat. I haven't bought a new one in at least 6 months although I am picking a new one up Monday so it's good to hear about the idle needle. It may take longer to break in than my others too.

Also, I hve found very few people who know about turning the spray bar to adjust the mid-range mixture. Bax has a good writeup on tuning the ST carbs in the Factory support forum. Anyway have a great day and weekend all.

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Post #: 12

RE: SuperTigre GS-40 break-in - 9/22/2007 4:50:46 AM

stanlattrell

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From: Leander, TX, USA
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Don -- if the LA 40's are truly going away and we have to use something else for Club 40 Novice, I've had some thoughts that might be interesting to try...... What if the ST GS 40 was propped to match the LA 40 performance when using 10% (or 5%) fuel for the Novice Class, and then step the fuel to 15% maximum and open up the props to "anything is acceptable" to set up an Intermediate class?? The standing start, 10 lap times on this setup would be in the low to mid 1:40's at the fastest, and would be a strong step up from the Novice speeds of mid 1:50's at the fastest. Advanced Class could still be TT Pro 40 or GMS 40 engines with 15% fuel and any prop you choose for times in the mid 1:20's to low 1:30's for well-flown, really groovin' races. This would be another strong step up, and this scheme would provide more roo