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RE: tower hobbies .46 engines - 8/25/2006 6:00:38 PM   
Bax


 

Posts: 12457
Joined: 4/26/2002
From: Champaign, IL, USA
Status: offline 		Please be aware that there are NO "recommended" settings. You are only given starting points. Sometimes they are close, and sometimes they are 'way off. Ideally, they should be on the rich side. You have to adjust the engine to get everything just right. The exact settings will depend upon the fuel, prop, and exhaust system used. The high-speed needle will change settings from day-to-day, as the humidity and air pressure changes (air temp will affect the air pressure). We've seen significant needle changes from a cool morning to a hot afternoon, and even more radical changes over two days because a major front came through and the weather changed from hot and humit to cool and dry.

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(in reply to opjose)
       Post #: 26

RE: tower hobbies .46 engines - 8/25/2006 6:14:16 PM   
RC-Bearings



Posts: 220
Joined: 10/8/2003
From: Glendale, AZ, USA
Status: offline 		The Tower is a rehash of a GMS engine that was originally produced for the domestic Chinese market. I imported them under the Raptor name a few years back until Tower bought exclusive rights to the design from GMS. GMS then improved the 47 and gave it a lot more power with larger props. You can easily get over 13K with an 11X6 APC on 5% nitro. None of the OS or TT will do that.

If you use 5-10% nitro, you will find these engines are a lot easier to manage. GMS designs engines more for the European style of lower nitro flying. Using 15-20% nitro is pretty much a waste of time and money with them.

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       Post #: 27

RE: tower hobbies .46 engines - 8/25/2006 7:28:59 PM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		Now you've done it!

I'm going to have to go tach my .46 TH engine thanks to your post....

heh....





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Build em'', fly em'', crash em'' and build more.

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       Post #: 28

RE: tower hobbies .46 engines - 9/5/2006 7:08:26 PM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		I tached my TH .46 with an 11x6 APC prop running 10% nitro on a test bench.

It will do 13k just fine when optimally tuned.

The problem with it is that using the TH muffler the engine will go far too lean and quit when turned up (say for uplines), so the mixture must be richened down to where the prop turns at between 9k-11k.

This is probably due to the low pressure output from the TH muffler.

The low back pressure on the TH muffler contributes to the .46's performance.

Many people put this muffler on other engines and obtain additional RPM's.

However this comes at the cost of lower tank pressurization.


I find no performance loss on downlines...

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Build em'', fly em'', crash em'' and build more.

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       Post #: 29

RE: tower hobbies .46 engines - 9/5/2006 11:53:22 PM   
RC-Bearings



Posts: 220
Joined: 10/8/2003
From: Glendale, AZ, USA
Status: offline 		Like I said, the GMS 47 has no problems running 13k with the 11X6 and does not suffer the tuning problems of the Tower engine.

quote:

ORIGINAL: opjose

I tached my TH .46 with an 11x6 APC prop running 10% nitro on a test bench.

It will do 13k just fine when optimally tuned.

The problem with it is that using the TH muffler the engine will go far too lean and quit when turned up (say for uplines), so the mixture must be richened down to where the prop turns at between 9k-11k.

This is probably due to the low pressure output from the TH muffler.

The low back pressure on the TH muffler contributes to the .46's performance.

Many people put this muffler on other engines and obtain additional RPM's.

However this comes at the cost of lower tank pressurization.


I find no performance loss on downlines...



_____________________________

Steel and Ceramic bearings for model engines
http://www.rc-bearings.com

(in reply to opjose)
       Post #: 30

RE: tower hobbies .46 engines - 9/6/2006 1:21:27 AM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		The GMS engine is a slightly larger bored unit so it is understandable that it would have slightly higher power output.

That said I was looking at one at the LHS with my own TH .46 in hand.

The carb, muffler, body, head, etc. were both otherwise identical. Even the serialization stamping uses the same digit sequence and font. This is not a co-incidence.

I'll bet that GMS merely produces them for Tower, and Tower merely repackages them in their own boxes.

They are so close that calling the TH version inferior would be tantamont to also calling the GMS one the same.

While the GMS outputs more power, I'll bet it has EXACTLY the same tuning "issue". I just MAY have to purchase one to check it out...

Though I would not call it a tunning issue, as most engines have the same problem, including my O.S.'s, and this board is repleat with posts reaffirming this. It's a flow problem that could be solved by increased pressurization or a pump.





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Build em'', fly em'', crash em'' and build more.

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       Post #: 31

RE: tower hobbies .46 engines - 9/6/2006 1:37:45 AM   
RC-Bearings



Posts: 220
Joined: 10/8/2003
From: Glendale, AZ, USA
Status: offline 		Perhaps you haven't paid attention to my earlier posts. I was involved with GMS when the 46 and 47 were first imported. The 46 and 47 are both made by GMS but they are not the same engine with a different bore. The head on the 46 used to be a cast design and was only changed when Tower started importing them. The porting on both engines is different with the 46 biased more towards high RPM power whereas the 47 will turn larger props more reliably in the midranges. The original GMS 46 would turn an APC 10X6 at well over 15k on 10% fuel. It would do this all day long with no tuning problems. As soon as Tower put the remote needle valve on it, the problems started. If you put the standard GMS carb on your Tower engine, you would eliminate the leaning problems. I did this on a couple of them.

quote:

ORIGINAL: opjose

The GMS engine is a slightly larger bored unit so it is understandable that it would have slightly higher power output.

That said I was looking at one at the LHS with my own TH .46 in hand.

The carb, muffler, body, head, etc. were both otherwise identical. Even the serialization stamping uses the same digit sequence and font. This is not a co-incidence.

I'll bet that GMS merely produces them for Tower, and Tower merely repackages them in their own boxes.

They are so close that calling the TH version inferior would be tantamont to also calling the GMS one the same.

While the GMS outputs more power, I'll bet it has EXACTLY the same tuning "issue". I just MAY have to purchase one to check it out...

Though I would not call it a tunning issue, as most engines have the same problem, including my O.S.'s, and this board is repleat with posts reaffirming this. It's a flow problem that could be solved by increased pressurization or a pump.






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Steel and Ceramic bearings for model engines
http://www.rc-bearings.com

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       Post #: 32

RE: tower hobbies .46 engines - 9/6/2006 3:07:03 AM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		Yeah, I found your post about this quite interesting.

Is the problem then soley with the remote needle?

Or is there a way to keep the remote needle on the TH engines and yet cure the problem?

Other than the obvious, buy the GWS in the first place and save the expense.



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Build em'', fly em'', crash em'' and build more.

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       Post #: 33

RE: tower hobbies .46 engines - 9/6/2006 3:19:33 AM   
RC-Bearings



Posts: 220
Joined: 10/8/2003
From: Glendale, AZ, USA
Status: offline
quote:

ORIGINAL: opjose

Yeah, I found your post about this quite interesting.

Is the problem then soley with the remote needle?

Or is there a way to keep the remote needle on the TH engines and yet cure the problem?

Other than the obvious, buy the GWS in the first place and save the expense.




I owned two of the Tower versions and neither one was reliable with the remote needle carb. No amount of tweaking worked.

_____________________________

Steel and Ceramic bearings for model engines
http://www.rc-bearings.com

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       Post #: 34

RE: tower hobbies .46 engines - 9/6/2006 6:28:57 AM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		How about a GMS with a remote needle carb?

---

Both of my TH .46's run reliably now that I've bench tested them and adjusted them as per my prior post.

The only problem I have is that I cannot obtain optimum RPM's in level flight from the engine without resorting to other means such as a one way pressure valve... but the later is not a great solution esp. when the tank is relatively full.




< Message edited by opjose -- 9/6/2006 6:32:41 AM >

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RE: tower hobbies .46 engines - 7/23/2007 11:02:36 PM   
brianstog


 

Posts: 2
Joined: 7/5/2007
From: Lumberton, TX, USA
Status: offline 		Interesting and very useful information you all have presented.

My TH 46 issue is I am maxing out RPM around 10800, using a 11x6 prop with 10% nitro. Any suggestions why it is so low?

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       Post #: 36

RE: tower hobbies .46 engines - 7/23/2007 11:31:04 PM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		Are you using the included muffler?

Is the engine fully broken in?



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       Post #: 37

RE: tower hobbies .46 engines - 7/24/2007 12:21:15 AM   
brianstog


 

Posts: 2
Joined: 7/5/2007
From: Lumberton, TX, USA
Status: offline 		yes, i am using the included muffler and have run a little over 1 gal of fuel to break in. on teh high end setting, i am a good 3 full turns open. it seems a little rich, however i read your previous post saying you were about 5 turns out.

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       Post #: 38

RE: tower hobbies .46 engines - 7/24/2007 12:56:14 AM   
opjose



Posts: 5830
Joined: 11/26/2005
From: Poolesville, MD, USA
Status: offline 		I wouldn't compare one engine to another based upon needle turns.

Longer fuel lines or other restrictions could mean that my 5 turns is the equivalent of your 3, etc.

If it seems rich and you've run over a gallon or more through it, start leaning it out to max RPM's then back off the standard 200 RPM's.

At worst try a slightly smaller prop.


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       Post #: 39

RE: tower hobbies .46 engines - 7/25/2007 8:09:24 PM   
prgonzalez



Posts: 352
Joined: 6/7/2004
From: KATY, TX, USA
Status: offline 		I haven't read the whole thread, so I am going to ask this question.

Have you try different fuel?

One time, my OS 46 FX was topping in the 10K, I switched fuel and went to 12K RPM.

My 2 cents.

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       Post #: 40

RE: tower hobbies .46 engines - 7/25/2007 8:21:54 PM