TOWER HOBBIES .75 PROP RANGE
 

Can you get buy with a 13-6 prop with this engine. I have it in a GP Shoestring and like the look of the 13" prop better than the 12" prop (huge cowling).

RE: TOWER HOBBIES .75 PROP RANGE
 

Motorman,


This engine would probably spin an APC 13x6 at 11,500 RPM, or better.
It is among the recommended sizes.

Use a colder glow-plug (not the A3, or Tower equivalent that probably came with the engine) and up to 10% nitro, for best power/economy balance.

Flyboy Dave uses this engine and may have something to add.

RE: TOWER HOBBIES .75 PROP RANGE
 

Some APC's are just prettier than others

RE: TOWER HOBBIES .75 PROP RANGE
 

MM,

Dar's estimate is right on the money based on what I've seen the Tower .75 do - 11,500 or so with an APC 13x6 or a 12x8. The .75 is just as happy with this relatively large load as it is with a smaller load that lets it do 13,000 rpm or more.

It's a good engine.

RE: TOWER HOBBIES .75 PROP RANGE
 

What is the largest prop that would work with this engine. I will be running a bisson pitts muffler. I was hopeing that I could try a 13-7 or 8 apc.

RE: TOWER HOBBIES .75 PROP RANGE
 

It depends on how much power you want (or need). It will swing the 13-8 OK, but it won't develop its max power & the engine temp will go up somewhat.

RE: TOWER HOBBIES .75 PROP RANGE
 

The .75 is in my GP shoestring that weighs 7.5 lb's. What kinda of rpm's do you think the .75 would turn a 13-7 or 13-8.

RE: TOWER HOBBIES .75 PROP RANGE
 

I keep eyeballing these Tower 75 engines and am itching to try one. I now have an OS 61 FX. How does this engine compare to the 61 FX?

RE: TOWER HOBBIES .75 PROP RANGE
 

Buzz,


It is supposed to be quite powerful.

...But some people had less than optimal experience with them.


Do a search here.

RE: TOWER HOBBIES .75 PROP RANGE
 

They don't even live in the same world. The 61 FX is like a seriously strong 46. The Tower 75 is a killer.

RE: TOWER HOBBIES .75 PROP RANGE
 

The workmanship and quality of mine looks awesome, on the inside and the ouside. This is an extremely tight true "ABC" engine. I have not run mine yet but I am willing to bet that it will be excellent. The Tower .61 is quite a bit more powerfull than a fx .61 according to model airplane news review.

RE: TOWER HOBBIES .75 PROP RANGE
 

The TH .75 weighs only 23oz WITH the muffler.

The 61FX weighs 23.6oz with the muffler.

So, the TH .75 is lighter--right outta the box.

Power? Not even in the same ballpark. Hell, not even in the same ball STADIUM. WORLDS of difference between the two engines.

Best I ever got out of a 61FX was an APC 12-6 at 10,500RPM.

My TH .75 engines crank 12,500RPM with a 13-5.

Thats almost identical load--but 2000RPM difference between the 2 engines.

The TH is $100. The 61FX is $170[X(]:eek:

The TH has a 4yr warranty if your a Super Saver Club Member. OS has a 2yr warranty.

I've had 8 of the TH .75 engines. I've sold a couple planes, so I'm down to 6 engines. I did have problems with 1 of them, and I sent it in for warranty. Long story short--I wasn't too happy with Hobby Services, but in the end, they did honor the warranty and rebuild the engine free of charge.

I really like these engines. I've had 8 of them and still own 6 of them. Whats that tell ya? Planning to buy more of them too.

If you want a speed prop for that Shoestring, try a 12-8 or an 11-10. FlyBoyDave uses an 11-7.5 prop on his .75 engine and it's in some type of high speed plane. He gets good RPM out of it and I'm sure it's a rocket ship.

Go for more pitch--not so much diameter. It will easily run 13,000RPM all day long and you won't hurt it.

RE: TOWER HOBBIES .75 PROP RANGE
 

Is the tower75 loud?

RE: TOWER HOBBIES .75 PROP RANGE
 

Depends on the muffler.

RE: TOWER HOBBIES .75 PROP RANGE
 

How loud is the stock muffler that comes with the engine?

RE: TOWER HOBBIES .75 PROP RANGE
 

Who makes a Pitt's style muffler for the Tower 45?

RE: TOWER HOBBIES .75 PROP RANGE
 

Hi Murray.

I'm not sure which Super Tigre muffler fits (Pitts style) but it is one of those. I used a modified Super Tigre in-cowl muffler on one of mine for a Top Flite Spit.

RE: TOWER HOBBIES .75 PROP RANGE
 

It's not that loud.

Run a larger prop and keep the RPM around 10,000 or a little less and it's pretty quiet.

The Bisson Pitts muffler is actually pretty quiet too.

RE: TOWER HOBBIES .75 PROP RANGE
 

Tower carries two pitts mufflers for the Tower .75-gms .76. One made by bisson and one by slimline.

RE: TOWER HOBBIES .75 PROP RANGE
 

Rcpilet,


If the silencer supplied with this engine is anything like the Tower .46 silencer, it is tuned to provide some boost to power, at a certain RPM range.
Wouldn't bringing the RPM down so low put the engine out of the boost range, making this engine as weak as an ordinary .61?

RE: TOWER HOBBIES .75 PROP RANGE
 

Of course, anytime you run a larger load and bring the RPM down on a 2-stroke--it's gonna cost you HP. But, I think the TH .75 has enough torque to spin a bit larger prop down around 10,000RPM and still put out reasonable thrust.

I don't think the TH .75 would be as weak as a 60 size engine at when running it at 10,000RPM. But, I'm just guessing. I don't have to worry about noise where I fly, so I run them at higher RPM.

I'm glad I don't live in Europe--or even near a field in the USA where there are noise restrictions in place. I asked about noise restrictions once at our field and the guys were laughing at me. "Noise restrictions? MMMMWWWAAHAHAHAHAHAHAHAHAHAHA! Fly whatever ya want, as loud as ya want."

RE: TOWER HOBBIES .75 PROP RANGE
 

Chris,


A tuned exhaust system has a particular RPM range, in which the air column within it attenuates in heterodyne.
This is the boost range, in which this system will augment the engine's power output.

However, if the engine is spinning just below this RPM range, this exhaust behaves like a particularly restrictive muffler, reducing the output more than would a normal muffler.

If 10,000 RPM is in that particular 'area', it is possible for this engine's ample torque, to be reduced significantly, due to these 'negative vibes'...


So if one wants to have this engine spinning in this RPM range, he should use an alternative muffler; not the tuned one, maybe a Pitts as you suggested.

...Or, an extension could be added to the tuned muffler, to get the boost at lower RPM...

RE: TOWER HOBBIES .75 PROP RANGE
 

I don't think the Tower .46 muffler is "tuned" as such. It's a very well designed high volume muffler yes, but "tuned"? I don't think so.

I've tried it out on a number of engines now - chinese clones, OS FX, SX and AX engines and the TT .46. With the APC 11x6 or the 12.25x3.75 props, increases I've seen range from 300 to 600 rpm depending on the engine. The increase seems more noticeable at 12-13k than it does at 11k, so its benefit appears to increase at higher rpm levels.

I doubt that the Tower .46, as good as it is, would provide an increase over an open face rpm reading.

RE: TOWER HOBBIES .75 PROP RANGE
 

Nope. It is just one mean piece of metal. My GMS 76 has a standard muffler & it's a pig (11,100 RPM with an APC 12-8).

I just swapped mufflers with one of my Tower 75's. The GMS is still a pig (11,400 RPM) with the Tower muffler & the Tower hardly noticed the difference -- 12,400 RPM with an APC 12-8 & the standard muffler & 12,700 RPM with the Tower muffler.

RE: TOWER HOBBIES .75 PROP RANGE
 

This engine is sounding like one hell of a deal, and I have not even had a chance to run mine yet (I live in WI). Maybe I should order another for my 4*60 kit laying on the shelf.:D
Bye the way, how close are these numbers to what a OS .91fx will turn?