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TT GP-42 vs OS LA 46

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Old 04-30-2013, 08:12 PM
  #26
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Default RE: TT GP-42 vs OS LA 46

The thunder Tiger manual on page 3 for the GP series states" GP-42 disp-cc/cu.in. , 6.49cc/ 0.396ci, bore= 21.2mm/0.835, stroke=18.4mm/0.724in
Don't know why it matters unless your using it in some kind of competition. I have had both and both the GP-42 and LA's and FP's all have been fine engines.
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Old 04-30-2013, 10:48 PM
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Default RE: TT GP-42 vs OS LA 46

G'day

My calculation (ancient HP-11c scientific RPN calculator) using bore, 0.846", stroke 0.748" (from TT site) gives .4205 which rounded to three decimal places gives .421 which is what TT's site says. So it would appear to be slightly bigger than a true 40.

I have one here but sadly it has no carby. If it did have, or if I could find one here in Australia, I would use it. Meanwhile I will keep using my OS LA 46 on its trainer and my Enya 40SS on its Sig Fazer.

Cheers

Mike in Oz
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Old 05-01-2013, 03:56 AM
  #28
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Default RE: TT GP-42 vs OS LA 46

That's a different bore and stroke from the numbers on the web site.
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Old 05-01-2013, 04:14 AM
  #29
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Default RE: TT GP-42 vs OS LA 46

G'day

Sorry but they are the same as the numbers on http://www.thundertiger.com/product/9041.html which is the GP 42 site that I looked at.

Perhaps there is more than one web site? And more than one set of numbers? Stranger things have happened.

Mike in Oz

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Old 05-01-2013, 05:09 AM
  #30
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Default RE: TT GP-42 vs OS LA 46


Quote:
ORIGINAL: mike109

G'day

Sorry but they are the same as the numbers on http://www.thundertiger.com/product/9041.html which is the GP 42 site that I looked at.

Perhaps there is more than one web site? And more than one set of numbers? Stranger things have happened.

Mike in Oz


Yes that is the numbers I was using. I was replying to fredscz who had different numbers he found in his manual.


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Old 05-01-2013, 07:06 AM
  #31
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Default RE: TT GP-42 vs OS LA 46

Quote:
ORIGINAL: Sport_Pilot


Quote:
ORIGINAL: mike109

G'day

Sorry but they are the same as the numbers on http://www.thundertiger.com/product/9041.html which is the GP 42 site that I looked at.

Perhaps there is more than one web site? And more than one set of numbers? Stranger things have happened.

Mike in Oz


Yes that is the numbers I was using. I was replying to http://<font color=''#00265e'' size=...fredscz</font> who had different numbers he found in his manual.


Tower lists the same specs as what Fredscz posted and is the numbers I used. I guess someone that has one could measure theirs to see which spec is correct? I guess if it really mattered anyway.
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Old 05-01-2013, 12:16 PM
  #32
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Default RE: TT GP-42 vs OS LA 46

Check the prices and specs on Tower.

Engine Price Type Carb Type Bearings Power Longevity
Super Tigre G-40 $75 Ringed 2-needle Ball 2nd Longest
Thunder Tiger 42GP $85 ABN Air bleed Plain 3rd Shortest
OS .46LA $85 ABN Air bleed Plain 3rd Shortest
Super Tigre G-45 $90 ABC 2-needle Ball 1st 2nd

The last 2 columns are my opinion only. I have run all of these. All are good engines.

Notice the prices. The ST G-40 is $10 cheaper than either the .46LA or the GP 42.
The ST 40 is a steal at the price. Look what it has. It is a ringed engine. Yes, it will take longer to break-in than any of the other which are ABC/ABN. It will last for a very long time.
It has ball bearings like high priced engines as opposed to a plain, bronze bushing. It has a 2 needle carb, also like the high priced engines.

If you are thinking of the OS or the TT, consider that the ST 45ABC is only 5 bucks more. This is a potent engine. It really has a larger displacement than the OS .46AX. St 7.5cc/.787 cu in. OS AX 7.455cc/.772 cu in. OK these are microscopic differences, but I'll bet you thought is was smaller and less powerful than the OS .46.

Horsepower and the size number on the box are for advertising only.
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Old 05-01-2013, 03:26 PM
  #33
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Default RE: TT GP-42 vs OS LA 46


[quote]ORIGINAL: iskandar taib

Is the TT .42 really a .40???? It's somewhat amusing - a friend of mine bought a pair, which were going to be used for CL Stunt. He was lamenting the ''fact'' that they were over .40, so he had to use the heavier .018'' lines rather than .015''. Maye he needn't have worried..?? As it turns out, all the competitive guys use .018s on .40s anyway, because they're more precise - less line stretch.

Iskandar
[/quote

Isky,

He wouldn't have to go to .018 lines until he went over 64 ounces according to the new rules. Wish that they went by FAI and you used what you wanted as long as it passed the pull test.

Dennis
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Old 05-01-2013, 05:52 PM
  #34
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Default RE: TT GP-42 vs OS LA 46

Unfortunately parts for Super Tigre engines are an unknown at this point.
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Old 05-01-2013, 06:44 PM
  #35
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Default RE: TT GP-42 vs OS LA 46


Quote:
ORIGINAL: mike109

My calculation (ancient HP-11c scientific RPN calculator) using bore, 0.846'', stroke 0.748'' (from TT site) gives .4205 which rounded to three decimal places gives .421 which is what TT's site says. So it would appear to be slightly bigger than a true 40.

I have one here but sadly it has no carby. If it did have, or if I could find one here in Australia, I would use it. Meanwhile I will keep using my OS LA 46 on its trainer and my Enya 40SS on its Sig Fazer.
Sell it to a CL flier. Should be easy to whip up a venturi and use it for Stunt. If I recall it's got some sort of weird arrangement for attaching a carb, but that shouldn't be a hindrance.

Iskandar
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Old 05-02-2013, 01:48 AM
  #36
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Default RE: TT GP-42 vs OS LA 46

G'day

The one I have predates the one with the bolt down carby. This is more like the old OS FP carby so it would be quite easy to make a control line carby for it. Sadly, no one around here (apart from an old bloke that flies CL Speed) is in to CL. Sometime I should try to see if the OS LA carby fits. It just might.

Cheers

Mike in Oz
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Old 05-02-2013, 04:59 AM
  #37
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Default RE: TT GP-42 vs OS LA 46

IMO the plain bearing engines will outlast the ball bearing engines for most people. When you consider ball bearings failing from rust, dust, and debris then for most the bronze bearings will outlast the ball bearings. However, if you fly in a fairly dust free enviornment, always use fuel with castor oil, always run out the remaining fuel in the crankcase, and have ball bearings that don't rust at the drop of a hat. Then the BB engine MAYoutlast the bushed engine.

Presently the ST's are made in China and quality is suspect. I doubt they would last long at all.
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Old 05-02-2013, 05:21 AM
  #38
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Default RE: TT GP-42 vs OS LA 46

Normally, I would trust TT before I would Tower. But then again they kept the spec that said their 52 four stroke had and air bleed carb long after they had changed it to twin needle.
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Old 05-02-2013, 05:21 AM
  #39
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Default RE: TT GP-42 vs OS LA 46

G'day

I agree that the plain bearing (bushed) engines are great for the average flyer but it is nearly impossible to get them to see that. The fact that engines have ball races in them seems to automatically trigger a "must have" response.

For trainers and small scale models, the good old plain bearing engine is hard to beat. I am currently using one in an old trainer that I use to help people to learn to land. It (an OS LA 46) is extremely reliable, it does not dead stick, it is cheap to run, is extremely easy to start, did not need a lot of running in, has plenty of performance for the average 40 size trainer, was relatively cheap for a quality made Japanese engine AND is even reasonably quiet on an 11 x 5 prop.

They are also tolerant of long storage and leap back to life once a bit of fuel has been sloshed through them.

They do like fuel with castor oil in it and this helps them to last a long time as the bush works best with plenty of oil.

Then again, I also love my Saito, Enya and Laser four strokes which do have ball bearings and do need a little more care and maintenance.

Cheers

Mike in Oz
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Old 05-03-2013, 11:52 PM
  #40
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Default RE: TT GP-42 vs OS LA 46


Quote:
ORIGINAL: Sport_Pilot

Presently the ST's are made in China and quality is suspect. I doubt they would last long at all.
I actually like the Chinese-made Super Tigre engines; I've found their quality, reliability, and longevity to be very good. I agree with Ed Moorman's comments about the Super Tigre GS-40 being an outstanding value. I have seen more problems with new TT GP-42s than I have with new Super Tiger GS-40s and GS-45s.

I also agree with Jeffie that Super Tigre engine and parts availability are not as good as the other brands being discussed here, unfortunately.
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Old 05-04-2013, 07:12 AM
  #41
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Default RE: TT GP-42 vs OS LA 46

We are hoping the situation with SUper Tigre is temporary.
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Old 05-04-2013, 08:09 AM
  #42
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Default RE: TT GP-42 vs OS LA 46

The os la that I have seen had plenty of power on a fair sized 45 size trainer . It also took more abuse then I have ever seen and came back for more . I was so impressed I bought one for myself and also don't forget its about the size and weight of a 25 size engine so its great for those planes as well .Cheers the pope
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Old 05-04-2013, 08:59 AM
  #43
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Default RE: TT GP-42 vs OS LA 46

To me the weight of these to non-bearing engines makes them. I use LA.46 in .25 sized planes. I have a TT .42 but have yet to use it to compare powerwise to the scale, the TT 42 weighs less.
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Old 05-04-2013, 12:32 PM
  #44
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Default RE: TT GP-42 vs OS LA 46

I am installing a TT42 on a Pheonix Models Sonic, its a large .25 size plane. It flies with a good .25 but needs more power to be happy in my opinion, flew really well with a Saito .40.
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Old 05-04-2013, 01:11 PM
  #45
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Default RE: TT GP-42 vs OS LA 46

Thanks all for the good info. I was still hoping to find out if the LA .46 was still made in Japan. I thought it was suspicious that if you look at an enlarged picture of the LA's on OS's website that you could see JAPAN molded on the crankcase on all of the other size LA's except for the .46. Because those are such a high volume engine for OS I thought it was possible that they outsourced production. (It would be the GP-42 for me for sure if they did)
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Old 05-04-2013, 03:03 PM
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Default RE: TT GP-42 vs OS LA 46

I guess if you get set on the OS you could always source an FP. I'd still opt for the TT though if it were me. My Pro .46 takes small prop abuse like nearly no other.
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Old 05-04-2013, 06:55 PM
  #47
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Default RE: TT GP-42 vs OS LA 46

See the hovering plane in my avatar? That's an OS 46LA in the nose.

But it needed a metal backplate from a 40FP, and the carb from a 40FP to make it run reliably. After buying and flying that 46LA, I bought and flew a TT 42GP. Then I ended up buying and flying two more TT 42GP engines. The TT 42GP has more power, runs better, and doesn't need any replacement parts to make it run great. The TT 42GP is everything the OS 46LA should have been.
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Old 05-05-2013, 08:22 AM
  #48
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Default RE: TT GP-42 vs OS LA 46

Ihave to agree with Old McDonald.
Try brucercengines.com he has a bunch of 40ish size engines , and as an insideer let me tell you his wife will be much happier if he were to sell a few, cheap!!
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