Tower .75
09-11-2011, 12:43 PM
#1
Tower .75
Back in 2007, I bought two Tower .75 engines for $99.99 each. I broke both in on my test bench and both ran very well. Later that year, Flaps and I built a Bill Evans' Pole Star flying wing. I forget what size engine it was designed for, but I used one of the .75s since I wanted some speed. With an 11-8 prop or a 12-7, the Tower would honk. The Pole Star was a pretty fast airplane. I still fly it every once in a while to this day.
The other Tower .75 got tossed in my engine drawer where a lot of used engines go. I didn't want another speed plane and I was using .46 sized planes with an OS .55 in them by what date I don't remember.
I love Sticks and had a Ultra Stick 60 powered by an SK .91 and later a Magnum .91 4-stroke. When flying buddy wanted to use the Mag .91 for his scale Douglas AD-2 Skyraider, I agreed to lend it to him. With the Mag .91 gone and the SK .91 in a Golden Era 60 build from MA plans, I needed an engine if I wanted to keep flying the Stick. Son-of-a-gun, in the drawer was a 4-year old Tower .75. I figured it wouldn't make enough power, but I installed it any way. Then I couldn't find a 13" prop for sport flying, so I used the 14-6 black Master Airscrew that was on the .91 just to check it out.
The engine cranked up easily and I gave it a tune, then taxied out and hit the power for takeoff. Right about that time, just a few feet above the runway, I got this wild hair to see if the engine made any power. Not expecting much, I yanked in some up elevator to square the corner to vertical. I certainly didn't expect an out-of-sight vertical climb. I mean, that's a big prop for an engine that is known as a high turning engine. I finally broke off the vertical climb, but not because I had to, the plane was getting hard to see. I spun down and flew out the flight.
Needless to say, I was pleased, astonished, elated at the performance of the lowly, Chinese Tower brand engine. It's a brute at a discount store price. No wonder they are no longer available. The OS .75AX is $229.99. It would have to be to be a lot better than the Tower to demand that price. I guess the same thing happened to its sister engine, the GMS .76. I'm sure glad I bought my two.
The other Tower .75 got tossed in my engine drawer where a lot of used engines go. I didn't want another speed plane and I was using .46 sized planes with an OS .55 in them by what date I don't remember.
I love Sticks and had a Ultra Stick 60 powered by an SK .91 and later a Magnum .91 4-stroke. When flying buddy wanted to use the Mag .91 for his scale Douglas AD-2 Skyraider, I agreed to lend it to him. With the Mag .91 gone and the SK .91 in a Golden Era 60 build from MA plans, I needed an engine if I wanted to keep flying the Stick. Son-of-a-gun, in the drawer was a 4-year old Tower .75. I figured it wouldn't make enough power, but I installed it any way. Then I couldn't find a 13" prop for sport flying, so I used the 14-6 black Master Airscrew that was on the .91 just to check it out.
The engine cranked up easily and I gave it a tune, then taxied out and hit the power for takeoff. Right about that time, just a few feet above the runway, I got this wild hair to see if the engine made any power. Not expecting much, I yanked in some up elevator to square the corner to vertical. I certainly didn't expect an out-of-sight vertical climb. I mean, that's a big prop for an engine that is known as a high turning engine. I finally broke off the vertical climb, but not because I had to, the plane was getting hard to see. I spun down and flew out the flight.
Needless to say, I was pleased, astonished, elated at the performance of the lowly, Chinese Tower brand engine. It's a brute at a discount store price. No wonder they are no longer available. The OS .75AX is $229.99. It would have to be to be a lot better than the Tower to demand that price. I guess the same thing happened to its sister engine, the GMS .76. I'm sure glad I bought my two.
09-11-2011, 04:55 PM
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RE: Tower .75
I have one that used to push a Bobcat around with a 11x7P at 113MPH.
It now needs a new home because of dumbthumbs and think I will put it in a 80" or so Cub.
It now needs a new home because of dumbthumbs and think I will put it in a 80" or so Cub.
09-12-2011, 01:54 PM
#7
RE: Tower .75
My TH 75 has been fantastic- it rips with the narrow-blade MAS 12x8. Run it on plain old FAI and OS # 8. LIke it so much I have a 2nd one NIB as a prized "reserve"
09-12-2011, 02:09 PM
#8
RE: Tower .75
Flyboy,
I used to hang around on the prop powered speed models forum. I recall the reason I bought those 2 was of how you liked them in your fast planes. Like I said, the one in the Pole Star turns a smaller prop and it's dang fast. I love the power and how it normally 1-flip starts. I was just amazed at how it turned the big 14-6 and pulled the Ultra Stick 60 around. Mine are both keepers. I do hate the bolt-on muffler.
Mine were both so tight I had to heat gun the cylinder to get them to turn over. I always bench run first, so after a couple of runs, they were fine. They were "crunchy" when new. I like that. They aren't going to wear out any time soon.
I've had Diamond Dusts with Rossi .40 Pylon and Fox .46ABC and a wudened, twin engine version that was scratch built. Plus I'vehnad a couple of Mach Racer deltas, without gear, of course. One had a Magnum .52XLS with a Rossi short pipe. The other had an OS .50SX with a Jett muffler. These were pretty fast, but when I rolled over 70, I noticed my eyes and reflexes getting much worse, so I had to fly slower planes. Getting old is a *****, ain't it.
I used to hang around on the prop powered speed models forum. I recall the reason I bought those 2 was of how you liked them in your fast planes. Like I said, the one in the Pole Star turns a smaller prop and it's dang fast. I love the power and how it normally 1-flip starts. I was just amazed at how it turned the big 14-6 and pulled the Ultra Stick 60 around. Mine are both keepers. I do hate the bolt-on muffler.
Mine were both so tight I had to heat gun the cylinder to get them to turn over. I always bench run first, so after a couple of runs, they were fine. They were "crunchy" when new. I like that. They aren't going to wear out any time soon.
I've had Diamond Dusts with Rossi .40 Pylon and Fox .46ABC and a wudened, twin engine version that was scratch built. Plus I'vehnad a couple of Mach Racer deltas, without gear, of course. One had a Magnum .52XLS with a Rossi short pipe. The other had an OS .50SX with a Jett muffler. These were pretty fast, but when I rolled over 70, I noticed my eyes and reflexes getting much worse, so I had to fly slower planes. Getting old is a *****, ain't it.
09-19-2011, 07:45 PM
#9
RE: Tower .75
Sorry for the slow reply, Ed....been up to my arse in alligators. 
Yes, I remember back then....those engines were the best bang for the buck in the industry.
Too bad things went haywire with the marketing, or whatever happened. The mufflers had
to be prepped before the first run, or problems would arise, for sure.
I think I still have a new one in the box too.
FBD.
Yes, I remember back then....those engines were the best bang for the buck in the industry.
Too bad things went haywire with the marketing, or whatever happened. The mufflers had
to be prepped before the first run, or problems would arise, for sure.
I think I still have a new one in the box too.
FBD.
09-20-2011, 11:00 AM
#10
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RE: Tower .75
Ed about the eyes. I just had mine overhauled with Crystalens. Waiting for the final tune up on the right eye. It is the dominant eye and needs to remove some secondardy cataract scar tissue and then a bit of PRK to perfect the vision. The left eye seems okay. So like you I have restraned myself from flying,
Chip
Chip
10-17-2011, 10:57 AM
#11
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RE: Tower .75
Gents,
Glad I am not the only one who likes the Tower and GMS engines. I have the T75 on a Senior Telemaster and the G76 on a Tower Hobbies Uproar - 60 size. Both are about 5 years old with minimal run time.......less than 15 hours on each. The Tower runs like a top. As long as there is fuel in the tank, the only things that stop it are the earth and the throttle cut switch....the latter of which is not always a given. The GMS 76 was running great till this weekend. ALL things being the same as they ever were, she has started choking on me on throttle up; i.e. once warmed up, I let the engine sit at idle for 10-15 seconds. I apply throttle and the sputtering and spitting starts. If I didn't react, she would die. After adjusting both needles and going through the battery of tests like pinching the fuel line at high speed, blah blah blah, everything seemed to be ok. It was a windy day so I wanted to make sure she would stay running when it got off the ground. I had my buddy hold the plane vertical and I gave it the gun. The sputtering started again and she would cut out. Tried this several times after minor adjustments and all ended with pretty much the same result.
I am guessing that some of this is normal but my engine skills are the weakest of my intellectual arsenal. Would appreciate some thoughts and/or suggestions to remedy the issue. I may just start with a glow plug change to see if that has any effect. Thanks in advance for your input.
Glad I am not the only one who likes the Tower and GMS engines. I have the T75 on a Senior Telemaster and the G76 on a Tower Hobbies Uproar - 60 size. Both are about 5 years old with minimal run time.......less than 15 hours on each. The Tower runs like a top. As long as there is fuel in the tank, the only things that stop it are the earth and the throttle cut switch....the latter of which is not always a given. The GMS 76 was running great till this weekend. ALL things being the same as they ever were, she has started choking on me on throttle up; i.e. once warmed up, I let the engine sit at idle for 10-15 seconds. I apply throttle and the sputtering and spitting starts. If I didn't react, she would die. After adjusting both needles and going through the battery of tests like pinching the fuel line at high speed, blah blah blah, everything seemed to be ok. It was a windy day so I wanted to make sure she would stay running when it got off the ground. I had my buddy hold the plane vertical and I gave it the gun. The sputtering started again and she would cut out. Tried this several times after minor adjustments and all ended with pretty much the same result.
I am guessing that some of this is normal but my engine skills are the weakest of my intellectual arsenal. Would appreciate some thoughts and/or suggestions to remedy the issue. I may just start with a glow plug change to see if that has any effect. Thanks in advance for your input.
10-17-2011, 07:21 PM
#12
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RE: Tower .75
My tower 75 is on the shelf right now since I don't have a plane for it...the plane died in a crash where I lost throttle...then elevator fluttered and you could imagine a 10 minute flight with a tower 75 at full throttle with an apc 12x7...with a fluttering elevator....that pain was never ending...after ten minutes the elevator broke and I had the chance to crash the plane safely... the carb broke on it's throat.
I ordered a JEN .91 replacement carb that fits perfectly on diameter but still have to grind the throat on a lathe since the throat is a bit longer and stays a couple of mm higher than it should to seal perfectly (anyone could give me the exact throat length on the original carb??)
This engine is definately the funniest engine I ever had!!
I ordered a JEN .91 replacement carb that fits perfectly on diameter but still have to grind the throat on a lathe since the throat is a bit longer and stays a couple of mm higher than it should to seal perfectly (anyone could give me the exact throat length on the original carb??)
This engine is definately the funniest engine I ever had!!
10-17-2011, 07:24 PM
#13
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RE: Tower .75
Most of the time the problem is on the tank!! so check your tank!
I hate when the clunk goes forward and pinches the line....and when the fuel tube falls inside the tank...it drives you nuts!
I hate when the clunk goes forward and pinches the line....and when the fuel tube falls inside the tank...it drives you nuts!
11-11-2011, 11:01 PM
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RE: Tower .75
ORIGINAL: Soko42vv
Gents,
Glad I am not the only one who likes the Tower and GMS engines. I have the T75 on a Senior Telemaster and the G76 on a Tower Hobbies Uproar - 60 size. Both are about 5 years old with minimal run time.......less than 15 hours on each. The Tower runs like a top. As long as there is fuel in the tank, the only things that stop it are the earth and the throttle cut switch....the latter of which is not always a given. The GMS 76 was running great till this weekend. ALL things being the same as they ever were, she has started choking on me on throttle up; i.e. once warmed up, I let the engine sit at idle for 10-15 seconds. I apply throttle and the sputtering and spitting starts. If I didn't react, she would die. After adjusting both needles and going through the battery of tests like pinching the fuel line at high speed, blah blah blah, everything seemed to be ok. It was a windy day so I wanted to make sure she would stay running when it got off the ground. I had my buddy hold the plane vertical and I gave it the gun. The sputtering started again and she would cut out. Tried this several times after minor adjustments and all ended with pretty much the same result.
I am guessing that some of this is normal but my engine skills are the weakest of my intellectual arsenal. Would appreciate some thoughts and/or suggestions to remedy the issue. I may just start with a glow plug change to see if that has any effect. Thanks in advance for your input.
Gents,
Glad I am not the only one who likes the Tower and GMS engines. I have the T75 on a Senior Telemaster and the G76 on a Tower Hobbies Uproar - 60 size. Both are about 5 years old with minimal run time.......less than 15 hours on each. The Tower runs like a top. As long as there is fuel in the tank, the only things that stop it are the earth and the throttle cut switch....the latter of which is not always a given. The GMS 76 was running great till this weekend. ALL things being the same as they ever were, she has started choking on me on throttle up; i.e. once warmed up, I let the engine sit at idle for 10-15 seconds. I apply throttle and the sputtering and spitting starts. If I didn't react, she would die. After adjusting both needles and going through the battery of tests like pinching the fuel line at high speed, blah blah blah, everything seemed to be ok. It was a windy day so I wanted to make sure she would stay running when it got off the ground. I had my buddy hold the plane vertical and I gave it the gun. The sputtering started again and she would cut out. Tried this several times after minor adjustments and all ended with pretty much the same result.
I am guessing that some of this is normal but my engine skills are the weakest of my intellectual arsenal. Would appreciate some thoughts and/or suggestions to remedy the issue. I may just start with a glow plug change to see if that has any effect. Thanks in advance for your input.
one thing to check is make sure the fuel barb isnt too far back in the tank which blocks fuel flow
hope this helps
12-06-2011, 06:55 PM
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RE: Tower .75
My brother and I have a mitt full of GMS engines...2-.47s, 3-.61s and 2-.76s..... all great runners.
I also have a TH.75 and it is a super strong, very reliable engine that has a home in my Tiger 60. As good as the OS we run.
Too bad that they are not available anymore....
On a brighter note, there is a gent up here that has a NIB TH.75 that I can get hold of for 110.00 shipped.....just might snag that one up for later.
I also have a TH.75 and it is a super strong, very reliable engine that has a home in my Tiger 60. As good as the OS we run.
Too bad that they are not available anymore....
On a brighter note, there is a gent up here that has a NIB TH.75 that I can get hold of for 110.00 shipped.....just might snag that one up for later.
12-07-2011, 01:45 AM
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RE: Tower .75
This type of Chinese engines' problem is carb.My opinion is;some carbs are leaking fuel from bottom hole of spray bar instead of spray bar itself when throttle barrel is on idle position and engine vacuum is most.The pilot is feeling very rich of idle running and begin to leaning the adjustment by pushing the LSN into spray bar further.Then the leak of the spray bar bottom seems good for idling,pilot thinks adjustment is OK but in fact LSN is far reach inside of spray bar,practically nearly choke of feeding by spray bar.(all of those are in idling position).Then when giving full throttle the far reaching LSN is partly coming back and partly opening the spray bar to feed fuel.And seems good running but fuel feed is very lean in fact and very vulnerable against some fluctuations of fuel feed at carb inlet nipple.Then Pilot feels ready to take off and gives full throttle after some idling(which providing some reserve fuel inside crancase).The engine roars and pulls like a champion until plane gains some altitude but same time nose was looking up and tank feed to carb was in trouble mostly because of inertia and head of fuel.Then suddenly(just reserved crankcase fuel was spent at same time) spray bar feeding becomes lacking to feed the proper mixture.The main reason is still LSN was partly blocking the spray bar to deliver fuel though throttle was in full position.
Shortly this symptom can be easily seen by looking at carb on full throttle position if after your your good idle adjustment still LSN is in contact with spray bar mouth(at full throttle position).
If so, then I recommend you to disassamble the carb,make sure the spray bar o ring will not leak at all and reassamble.I hope I could explain.
Shortly this symptom can be easily seen by looking at carb on full throttle position if after your your good idle adjustment still LSN is in contact with spray bar mouth(at full throttle position).
If so, then I recommend you to disassamble the carb,make sure the spray bar o ring will not leak at all and reassamble.I hope I could explain.
12-07-2011, 03:59 AM
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RE: Tower .75
Does anyone have the inside scoop regarding why the Tower engines are unavailable? The last time I checked their website, it shows them "Temporarily Unavailable". Apparently, they must think they will eventually get some or they would have flagged them as "Discontinued".
12-07-2011, 05:37 AM
#20
RE: Tower .75
Buy the Fox .74 instead. It is a stronger engine with a better carb. You can get 50% off if you trade in a junker engine.
http://www.foxmanufacturing.com/inde...roducts_id=289
50% off is $121 and the Tower .75 will likekly cost more than it did if they ever produce it again.
http://www.foxmanufacturing.com/inde...roducts_id=289
50% off is $121 and the Tower .75 will likekly cost more than it did if they ever produce it again.
12-07-2011, 07:33 PM
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RE: Tower .75
I bought a Fox .45 once and returned it as soon as I opened the box. It was ROUGH looking. I know, I know, beauty is in the eyes of the beholder, but I figured if it looked rough outside, it was probably just as rough inside. I might try it again.
12-08-2011, 05:57 AM
#22
RE: Tower .75
ORIGINAL: ma_mulcahy
I bought a Fox .45 once and returned it as soon as I opened the box. It was ROUGH looking. I know, I know, beauty is in the eyes of the beholder, but I figured if it looked rough outside, it was probably just as rough inside. I might try it again.
I bought a Fox .45 once and returned it as soon as I opened the box. It was ROUGH looking. I know, I know, beauty is in the eyes of the beholder, but I figured if it looked rough outside, it was probably just as rough inside. I might try it again.
The finish is no worse than many of the gas engines out there. But being smaller it looks rougher than that. They are this way to keep costs down while competing against imports. The insides are indeed well made and the new carb is great. The newer engine castingshave a much better finish, but I do not think the .45 RC is among the newer castings, though the CL version is much better.
http://www.foxmanufacturing.com/inde..._image&pID=278
http://www.foxmanufacturing.com/inde..._image&pID=278
http://www.foxmanufacturing.com/inde..._image&pID=278
12-18-2011, 05:41 PM
#23
RE: Tower .75
I will stick with my Tower .75's untill they are extinct from the planet. Sure the Fox's are American made, but they are just butt ugly when it comes to looks.[X(] I have met a couple people over the years that talked about them, but thats about it.
Sure the Fox's are American made, but they are just butt ugly when it comes to looks.[X(] I have met a couple people over the years that talked about them, but thats about it.
12-19-2011, 04:44 AM
#24
RE: Tower .75
but they are just butt ugly when it comes to looks.