dashunde

I'm thinking about putting a .75 of some variety on a Fliton 330, and I'm wondering what a good choice would be?

I'm looking at a Tower .75abc, and the GMS .76 ringed, I'd like some first-hand thoughts on these two and I'd also like your opinions on other inexpensive engines you've had good luck with??
ASP?

I'd even think of going .90 if the right one was presented.

Thanks!

AMB

SK and Super tigers are good engines and under $100 martin Have both 0 issues 40 thru 90s

w8ye

My Feedback: (16)

The GMS 76 has a Dykes type ring and is not very popular.

The Tower 75 is very popular. Its a real runner. You will like it. The Tower 75 is ABC

dashunde

Thanks for the quick replies guys.
A guy I know told me to avoid the GMS, but did not give a good reason why. That ring maybe?

I'm reading all over here that the Tower's scream, but have goofy/burbling carbs? Thats what I am gleening from it at this point anyway.
Are the recent 75's coming out ok? How about durability? I know its not a $200 OS, but still want some "life" out of it.

Keep the thoughts coming... very interested in this one, its the cornerstone of my project.
Been thinking Siato 100... but once I'm into that price range I might as well keep going onto the EF/Brillelli combo... its inevitable though.

summerwind

the build of the Tower .75 is from what i can see, excellent.
the power is amazing for the price......this engine pulls my 6lb. 1000 square inch Big Stik straight up with no tendancy to stop.............i actually have to stop it before it goes out of sight............but the carburation at this point is dissapointing. i'm going to try another carb this weekend........if it doesn't straighten out, then it's going to be replace by an OS .91 surpass.

ianwynne

Hello w8ye:

>The GMS 76 has a Dykes type ring and is not very popular.

Could you please expand on your statement. Is the Dykes ring a problem or is there some other reason why this engine isn't popular?

Or is it that the Tower engine much better for a very similar price?

I will be grateful for any information you can give.

Thanks.

Bye, ian

w8ye

My Feedback: (16)

For some unknown reason, the GMS 76 is rarely talked about on here.

I had one for a while a few years ago but never flew it. The only one I've ever noticed.

I've been around 3 Tower 75's they all ran perfect right out of the box and were easy to set up. They had/have excellent mixture control through out the throttle range.

The other day my friend ran his on 15% Omega, 10% Cool Power, and 10% Byron's without readjusting the needle valve. It appeared to run about the same with each fuel.

w8ye

My Feedback: (16)

The Tower is $5 cheaper and Tower often has sales incentives with them

An engine with a Dykes ring like the GMS 76 has poor compression when you ease the prop through by hand. But has good compression when flipped through fast.

They are a little more friendly when you use an electric starter.

The low tension ring is "L Shaped" and sets on the top edge of the piston. Compression pressure gets behind the ring and forces it out against the cylinder wall to make the seal.

Harry Lagman

i have worked with both the Tower .75 and the GMS .76. The examples I have seen have carburated quite well, suffering no glaring issues with mixture control.

Our field has featured far more of the GMSs than the Towers, mainly because GMSs are sold by one of our LHSs.

I would get the Tower if I was going to use the engine in a high rpm, sport/speed application where an 11x8 or 11x7 prop was going to be used and 13-15K rpm was the norm. Conversely, where a bigger prop is to be used (scale, 3D, lower speed sport) the GMSs will work well. I saw one guy's GMS .76 hauling an APC 13x8 (a bigger prop than I'd recommend) and it happily pulled 10,800 rpm on 5% fuel - that's stronger than any .91 four-stroke I've seen (YS excepted).

Make sure the GMS .76 comes with the Tower style three piece muffler, because it is worth a few more RPM over the older two piece finned muffler without much of a noise penalty.

Be aware that both engines are not manufactured to the same quality standards as the premium Japanese, Euro and USA stuff, so the performance of each engine can vary from example to example.

If you are going to run either the GMS or Tower engines really hard for many hours, it's a good idea to replace the bearings with good quality bearing house equivalents.The OEM bearings will eventually fail under hard service.

Iflyglow

My Feedback: (79)

Go for the Tower .75, you will not disapointed. I have well over ten gallons through mine, and it will run with the best of them. It starts with one simple back snap of the spinner. WC 10% extra premium fuel with OS #8 plug.

Fastsky

I have an SK 80 and could never get it to run very well so pulled it from the plane. I don't like Super Tigers based on my experience with them and won't buy one. No experience with or seen GMS engines. Tried a Tower 75 engine, love the performance and the sound with a Pitts muffler. Found it reliable and strong enough so mounted it on my Stuka with happy results. Now another one is on my new P47. Its the best engine in the 60/75 size range imho.

NM2K

My Feedback: (14)

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What didn't you like about the SK .80? Are you aware of the timing differences and how it was intended to pull really large props instead of screaming with smaller props? Just curious.

Yes, I have one, but haven't ran it as yet. <G>

I also have the .50 and two .90 SK engines. Also unran. Surgery on August 6th should get me back in the ball game.


Ed Cregger

Turk1

Hi Big Ed wish you a fast recovery and good luck.
My SK 80 is working great without nitro,self mix fuel.I would try to test it until find out what is wrong.

Fastsky

I was unable to even start the engine with the suggested factory settings, especially the low speed needle valve. When I did find a setting that would allow it too start and then trying to tweak it from there the engine ran erractic and I was unable to get over 10,000 using a modest prop. I had the plane to the field about 6 times trying different things and gave up. Maybe I just got a bad one or maybe I was just doing something wrong. I have OS in 40, 46, and 61 size, TH in 61 and 75 size, and ASP Super Series in 52 size engines and like them all because they have never gave me problems tuning or breaking in so thats what I am sticking with. The OS 61 runs very reliably but has only modest output for its size. Thats why my favorite is the TH and bump it up to the 75 size.

Turk1

Fastsky dont give up.Contact with Kangke,they are great people and Im sure they will solve your problem in a way.

pilotpete2

Hi Ed,
Best wishes for a speedy recovery.
I finally got to maiden my Goldberg Extra 300 (old BIY kit) yesterday with the ST G90, engine performed very well, transition is great, I can only imagine what it'll be like when it gets 3 or 4 more gallons thru it[8D].
Now as to the plane, no way do I fly that good something is wrong here, it really does land easier than a trainer, I thought my 4 star 60 was smooth!
Good luck,
Pete

daven

My Feedback: (1)

I would go with the super tigre .90 myself.

playntraffic

I have the TH .75 on a 7lb extra 330S. It has good power and will hover at 95% power. Good idle and transition. Runs strong on a 13x6 APC. Took about two gallons of break-in to get there.

I have a SK50 that I bought for another plane. I am sold on SK. I am purchasing a SK90 to take the place of the TH75. The TH75 is a strong screamer. It deserves to be on a plane that is built for speed. The SK90 will swing a 15x6 prop. That is what I am looking for in an aerobatic engine.

SK has a 70, 80, and 90. The weight is almost the same and the price is within a couple of dollars of each other.

Iflyglow

My Feedback: (79)

Fastsky,
I totaly agree with you on the TH .75. My TH .75 has led to atleast 10 sales that I know of in my area. These people were sold on it when they seen it perform in my Shoestring.

blw

My Feedback: (3)

Two excellent engines for under $100 would be the Evolution .46NT and .455 PTS.

dashunde

Thanks for all of your thoughts guys, very good stuff above.

I think I'm going to pass on all 2c glows for this build though.... a Saito 100 is my ticket this time.

I wanted to avoid going 4c due to the cost... I was thinking that if I go as high as a Saito, I might as well move on to a larger gasser, but when it all adds up (high$$ servos, few extra bucks for the larger plane, etc) it gets pretty pricey....
So the Saito it is on my Fliton 330.

If I ever (yea, its inevitable) build a fast pattern plane I'll be sticking a TH.75 on it though.
Humm... says on Towers site... that a Venus40 can handle up to a .70 4c... reads like a invitation for the power-hungry, eh?
Wonder if it gets control flutter??

Rcpilot

My Feedback: (78)

Thats BS.

The TH .75 has a great carb.

The guys complaining about "burbling" carbs haven't bothered to spend 15 minutes actually adjusting the low end properly. The engines are almost always rich from the factory and need to be adjusted for your prop, altitude, fuel and temperature. The carb has needles for a reason--so you can adjust the engine for best performance.

I've never had a problem with a TH .75 carb. I currently own 3 TH .75 engines and have had, at one point, 8 of those engines in my fleet. They work great at all RPM ranges. You just need to tune the low speed needle. Anybody can tune the high speed needle and then complain that it won't idle or transition smoothly. But, truth be told, those guys didn't bother to adjust the low speed needle. So, that makes it a bad carb. B.S.

If you just spend 15 minutes adjusting the low speed needle, they will run like a Swiss watch.

The low speed needle effects the ENTIRE RPM range, from idle up to well over 1/2 throttle. If your not going to bother with adjusting the low speed needle, expect it to run like crap below 1/2 throttle. It takes only minor adjustments to tweak that low speed needle for perfection after you get it close to the sweet spot. The thickness of a screwdriver blade either way will have an effect on how it runs.

Best kept secret in the hobby for under $100.

Harry Lagman

Careful now. You'll have your post deleted for "being argumentative".


Clearly, you haven't read the posts documenting problems with Tower .75 carbs, at least one of which was solved by a carb change (supplied by Tower). Every Tower .75 engine I have seen has had a good carb, but I'm not silly enough to assume that what I have seen pertains to every Tower .75 engine out there. Are you?

Go back and read the posts where the carb swap solved the problem. If you think the poster is BSing or is an inept tuner, call him out directly.

quepasa

I bet rcp is right more than hes wrong!

The TH-.75 sounds like a great "go-fast" engine!

misterpanda

My TH .75 has always been run at 8,600 feet elevation and, even then, it's a "rocket" with a 12x8 MAS on FAI fuel. I hve yet to experience what has to be its awsome performance at or near sea level.