brunoq

My Feedback: (29)

I Posted a reply in another forum in regard to this matter however, I think posting a new thread will get better exposure thus producing a better response, well here goes..
Wondering minds want to know.............................................. . Has anyone else besides me noticed the huge difference in power between the TT-46 Pro and the TT-40 Pro?
According to Dave Gierke in MAN March 2001 issue, there was a shootout done between 8 or 9 .40 engines. The TT-40 was one of these tested and showed to be a very powerfull little engine. The RPM Figures for the TT-40 Pro with APC props are as follows:
12X6 = 12700
11x7 = 12100
and the TT-46 Pro in another review but also using APC props was turning the following figures:
12x6 = 10300
11x7 = 10500
Am I missing something here? have I gone mad? Or am I just nuts?
I curious to know if anyone has done a one to one real life comparison between these two engines. If anyone has an extra two cents I'd like to hear it.
Bruno

Sport_Pilot

The TT.46 does a lot better than 10,500! Unfortunately many magazines do not break in an engine. Clarence Lee who claims to be an expert, only breaks in the engine for 1/2 an hour. IMO such tests are almost meaningless!

Dugster

Not to mention; fuel, temp, altitude above sea level, humidity, etc.....

John B

My Feedback: (1)

The BEST little engine I have had was a tt pro .40
had it on my somthin extra and it would pull it out of a hover no prob. put a 12.25 X 3.75 prop on it and it worked great!!!
Had one offer to trade it for a .46 . The owner was of it was sure it put it more than his. that little .40 is definately a workhorse.
John.

Ed

Bruno: I think that you are focusing too much on RPM, instead of more importantly, THRUST. I.E. - a Tee Dee .049 may turn 20,000, but that certainly does not make it more powerful then a .40. Larger engines typically rev lower. I would almost assume that the TT .46 has a slightly longer stroke, and would rev a little slower then the .40, but you really know that it's going to PULL better. " Ain't no substitute for displacement "

And then there is the possability of two different reviews, by two different people, different set of conditions, etc.
Apples & oranges ya know.

Just an educated guess ? - Jim

brunoq

My Feedback: (29)

I really think torque has much to do with RPM, heck Torque is what gives you RPM. Merit this situation. Lets say an APC 12x4 is turning 12000 rpm static, doesn't this mean there is enough torque to turn it at 12000?
If one engine turns an APC 12x4 at 12000 and another at 10000 this should indicate there is more torque produced from the engine which is turning the same given prop at a greater speed (i.e RPM). True, more torque will turn larger props with greater authority which in turn creates higher RPM! I am seeking to use an engine which will turn an APC 12X4 at a greater RPM and as far as I can tell the 40 is the better suited of the two to do so even if it has a larger I.C. capacity. IMHO I believe there is not enough emphasis on Torque so we are left to clue in on RPM stats. Now, had you commented on my over emphasis on HP we would have seen eye to eye. HP ratings are given using retarded prop sizes, who flies a 60 sized airplane on an 8x6 prop? :stupid: I am really curious to know if someone has compared the two.
Bruno

Dave Bowles

My Feedback: (7)

I would almost bet money there has been a misprint and the .40 was tested with a 10X6 and a 10X7. 12X6 and 11X7 are common props for .60 size engines, some of them would be doing good to turn them 12,700 rpm on the ground.

jaka

Hello!
When I had a TT.40 Pro SE engine a couple of years ago and used it in Q-500 pylonracing( 80/20 straight fuel, no nitro)typical rews were 13400-13600 rpm using a APC 10x6 propeller.
My friends who also used TT.40 Pro Se engines recorded similar rpm figures on there engines.
Using 10-15% nitro wil of course raise the rpm somewhat...perhaps 500-1000 rpm.
As I said in a previous letter the TT.40 Pro Se is only a bored and stroked version of the .40 engine.
The figures mentioned for the TT .40 Pro Se (12600rpm using a 12x6 propeller)Is definitely wrong! It must be a editing mistake! No .40 engine is capable of those rews on such a large propeller.Even the most powerfull .40 engines used in international pylonracing today,such as the the Dutch MB or the Russian IR or the American Nelson or Jett engines will produce these rpm on such a large propeller (12x6) and I´m speaking of engines capable of delevering nearly 4hp at 30000rpm.
Both the TT.40 and .46 engine are good sport engines capable of deliverng good power(trust) but it is the old saying that still rules "There is nothing that beats cubic inches"!!!
I would definitly go with the .46 engine if I wanted to turn a large (12x4-12x5)propeller.
The .46 engine is more powerful and delivers more trust at lower rpm!

Regards!
Jan K
Sweden

brunoq

My Feedback: (29)

I disagree with you that there is no substitution for Cubic inches. I am still leaning towards the 40 being the stronger engine between the two in question. Keep in mind, .06 cc is not all that much more. Although it may seem like a much bigger displacement it really isn't much. Using stock mufflers the 40 turns the same prop much harder than any budget type engine in its range, that is to say engines we are familiar with here in the States, OS, Supertiger, Enya, Magnum, Irvine, etc,. The TT-40 seems to have a tuned effect on the stock muffler attributing to the relatively high rpm figures. I can almost guarantee that the printed rpm figures are indeed not a misprint as the review list rpm figures for all prop sizes the engine would normally turn. And they are all within proper proportion.
Also, the engine review was undertaken by Dave Gierke (importer of the awesome Aviastar engine line and in many Hobbiest option an expert in matters of the glow engine). Dave made mention in the review which stated the fact that this little engine produced unusually high rpm figures and attributed some of it to the tuning effect of the stock muffler.
I have to ask myself, why will a Chevy small block 305 in an 84 Z-28 Camaro only produce some 185hp when the same block (with the same cubic inch displacement) 10 years later can produce 235hp. They are both using the same cubic inch displacement. I'd have to credit it towards tuning.
Therefore, there is a substitution for displacement its called Performance, so there is no substitution for modern technology.

Bruno

Sport_Pilot

Gota be a misprint, or bad review. Even in the summer my TT Pro 46 turned a 11-7 at just over 12,000 RPM!

brunoq

My Feedback: (29)

11x7 at over 12,000?, now this is usefull....What is your altidude and which fuel where you using?

Bruno

Sport_Pilot

1000 feet and 15%, APC prop. It turns a 10-6 at 14,800 or so, 11-5 at just over 14,000 just under 14,000 on a very hot day. The thing is it didn't do this until runing a couple of gallons through it. How can you do accurate reviews without breaking an engine in? The results can vary wildly especially with ringed engines. Altitude and temp can also affect it but not as much as break in. Another factor which also could determine product quality is that they only test one engine. Results could vary from engine to engine. Results that are close to each other would indicate good quality control.

Face it magazine reviews are there to sell products! You can't tell the differance from products you know are very bad or very good! Take MAN's Chris Chanille (SP?), he is always saying that OS-5 plugs are the best on all 4S engines in all situations, no matter what. I know for a fact that my TT .91 runs the best with OS-F plugs only on 5% nitro or on fuels with high oil content. On 25% nitro K&B plugs are the best. If I were him I would stop taking that OS money, it would be easy for a company to prove him wrong, IN COURT!

splatt

to our friend in sweden... the saying is " there's no replacement for displacement"

brunoq

My Feedback: (29)

This is exactly the type of information I was soliciting. I appreciate your input in regard to the prop sizes and thrust indicating values and will definately put it to use. I agree with your comment on the reviews and absolutes on any one certain product. Too many times great products are dismissed by bad reviews or even biased opinions. Take the MDS .68 for example, it is a great running engine which requires proper break-in and care (how be it often a little more than those most widely accepted (such as OS)), however, reviews which are undertaken imporperly give it a bad name, of coure one or two bad decisions on a certain carb or material doesn't help it much either. Then again take OS into consideration, it is a great engine but they've had more then their share in choice of bad or improper materials. (please read ABN FS series and wheaties bran breakfast flakes ). Anyhow, Thanks again for your input.

Bruno.

Grumpy Monkey

My Feedback: (7)

Ok, heres the deal, to settle this once and for all I am willing to do a comparison test of a NIB .40 against my NIB .46. I will break them in identically, run them side by side at the same elevation to the 1/32th of an inch, run the same fuel and the same prop, then rotate the props between them and test again. The only catch is.... Someone has to give me a NIB TT 40, hehehehe

Good Luck,
Warren

brunoq

My Feedback: (29)

Warren, I will hold my breath for someone to give you a free NIB 40 Pro. Let me know when you get it and run your tests!

Grumpy Monkey

My Feedback: (7)

Actually, It was just a bit of sarcasm to lighten this post up a bit. Its comparing apples to slightly riper apples. Not a big difference really IMO. There are 10 billion different variables (ok, maybe not 10 billion) that can be percieved and changed from 1 day,plane, location,needle setting, bad casting runs, etc to the next to give varying results under the given topic. Me personally, I just ordered a TT .46 pro because of the supposed .25 extra BHP. The bore is slightly bigger and the stroke is the same. I see the .46 as a stroker version of the .40 which means thearetically, I should get a little more HP and torque out of it but who knows. Just my opinion, please dont flame me for it !

Warren

Jazzy

Bruno, I almost didn't say anything but, what the heck.
(Sorry if I'm intruding)
In your analogy of the two Chevy 305s just substitute in a 350 vs. the 305. More torque? (It's just an open question )
Not a whole lot more displacement...
Back to the RPM figs. Yeah, that .40 sure can run! I have no doubt it is a great engine. Look what happens after 13600 RPMs. The torque starts dropping. It would seem from Dave G.'s review that the 'torque band' one should try to keep this engine in is between the RPMs 12.5K and 14.5K. If that little gem is turning 12K static with an APC 12X4 what's going to happen when the prop unloads and the engine revs up past 14K? Maybe all of the previous torque wouldn't be necessary at that point- I don't know...
I don't have a review of the Pro .46 to compare the .40's to.
I don't think I'd use it to haul around a 5-6.5lb. plane with though. A fun fly or light plane - you bet!
All I'm offering here is a slightly different perspective.
I'd like to have one to experiment with - that's for sure!

Whatever you decide on - best of luck!
If you do get the Pro .40 let us know how it goes! Definately!

Jeff

brunoq

My Feedback: (29)

I've already considered and substituted the 350 for the 305. It came out of a 78 Corvette. This car has a small block 350 which is a pathetic engine, producing under 200hp. I've seen stock 305's put out 25 to 40 percent more! Take into consideration this engine uses different heads, exhaust, porting, timing, etc.. etc..
Displacement all on its own isn't a clear indicator of how much power an engine will produce, there are several cars out there with larger displacement engines which are essentially de-tuned for fuel economy, longetivity, reliablity, etc.. etc..
In our hobby, we unfortunately face the same situations. For example OS's economy line the La series, (air bleed carb, cheaper linings, etc). I can't make an accurate power measurement by displacement.
Real Performance should be measured by one set standard. I'm doubtfull this will Ever happen. So we are left with our own tests and opinions. I'm grateful for Forums such as these where we can communicate with fellow modelers. We are the ones who have real world, hands on experience with a given product and are normally non baised. I value your personal test results and will naturally grant a higher merit to the common modeler with a tach.
I'm sure someone out there will supply us with an answer.
Thanks for your reply, I would never consider it an interuption.
Bruno

brunoq

My Feedback: (29)

I would rather have the TT-46. I've had one before and loved it. I'm just waiting for someone with a real life test post to make my decision. I'm just like every other guy who wants more, more, more, more. We can become power thirsty and, like women, we are always watching our weight. I know Thunder Tigers specs claim the 46 is slightly lighter, if it is its got to be in the muffler. ( if it is its , cool huh? how'd I do that?). And besides it just sounds better to have a bigger engine. But when it comes right down to it I want the higher performing engine. Whether it be the 40 or 46. I currently have an old Como .61 with a 12x6 prop. I've tried the 11x4 but was not impressed with the performance, it just sounded louder. I'm sure the Thunder Tiger 40 0r 46 would turn an 11x4 with much greater authority. I've taken a liking to TT's for their power and cost value.
Thanks for your input.
Bruno

Grumpy Monkey

My Feedback: (7)

I will be getting the .46 on tuesday or wednesday this week so I can do some tests on it after I break it in and post some results probably next sunday after I get back from the field. I dont have a .40 TT to compare it to, but do have an OS .40 which I havent done any tests on so maybe I will do that one as well and post its info just for the fun of it. The .46 is goin on a GP Mustang. The .40 is on a scratchbuilt stick. If the stang isnt done by the weekend I will throw the .46 on the stick and give it a go.

Warren

John B

My Feedback: (1)

warren , the tt.40 cranks alot better than any of the os .40s I have seen, only one close was a sf

brunoq

My Feedback: (29)

I completely agree with John B, I think you'll be in for a pleasant surprize. The TT-40 will spank the OS 40 all the way to the ceiling. I am however very interested in your findings of the .46 TT-Pro. OS makes a very user friendly product consequently, in their quest to make a product reliably simple to use they fall off on perfomance. OS is a great engine for sport flying but I wouldn't use it on a competition type airframe. (let me clarify my OS statement to not include the OS140RX & OS160FX-FI, two awesome work of art engines). I'm sort of jealous with your Mustang (one of my favorite warbirds, it sits along side the beautiful Spitfire).
I will anxiously await your results,, Ya know I will!

Thanks Warren.
Bruno

John B

My Feedback: (1)

I have the gp mustang also.....put a fp 60 up front and she really rips

brunoq

My Feedback: (29)

Now why'd you have to go and do that? I have been fighting the urge to buy one and there you go!
Well, since we're on the subject, have you seen Giant Scale Planes P-51? I have been tempted to buy one but will hold off as long as I can. Kyosho's also got a nice 40 size, the covering is not the greatest material available but its got a killer paint scheme. There's another one developed by Okay Manufacturing the EZ Mustang marketed by Altec. I've seen that one and believe me its a master piece.
Check out my 33% Cap 231 EX with 3W-Gas Twin!!

Bruno