camdyson

Bill,

The pumped 70's also mean you can have a straight-out exhaust with no muffler - neater, simpler, and more realistic sound(louder)
Look at Norman's Saitos in early posts - same deal but you wouldn't need the Perry pumps.

Otherwise I'm sure a pair of FL70's would do the job cheaper.

Cam

p.s. I was on a roll with this plane - not only jagged Vailly's last 2 1/9 pilots, I think I got Tower's last 2 OS70's too... Now if my discontinued JR gyro turns up, it'll be a hat-trick! (that's cricket talk for you Yanks, means 3 in a row...)

Bill Giulian

My Feedback: (38)

Tim. I REALLY appreciate your comments. I totally agree with what you said. In fact I was kind of leaning in both directions. The main reason I shied away from the 81s was that I was led to believe that more power was inadvisable. I called one of the local hobby stores today and they stated they had a FS 70 II in stock. I have to wait until Saturday to go there. If that works out I will use the FS 70s. If not, I will go to the 81s. I guess you wouldn't want to share your empoyee perks with me. Anyway,thanks a lot for your help and guidance. Bill.

Bill Giulian

My Feedback: (38)

Cam. Thanks a lot for your suggestions. Do you have a lucky cloverleaf you carry around in your pocket? By the way I think I got the last B-25 currently in stock for the moment. So there. Just one question. Do your planes fly unsidedown in Australia? Bill.

camdyson

No, but we have to reverse the polarity on our electric motors to get them to turn the right way......

envallm

Has anyone else used the "Ultimate" engines successfully? I have a pair of them and havent yet been able to start building my B25 yet, but would really like to know if I should change these engines, as I plan to break them in on a stand before building. Can someone post some pics of the "Ultimate" engines mounted? Any feedback would be appreciated.

Thanks all

norm

Good to hear some guys bringing back the glow on this thread..I was away for the last 2 to 3 pages.

Hello Morganew,
Hello Camdison,
Hello Bill,

I Had time to study this question for 2 months waiting for my B-25 back in august 2007. I considered first size due to the 5.75 inch cowl, then power due to the weight of the aircraft and finally weight of the engine. the best power to size & weight ratio is the OS70 Ultimate and the Saito 82. the other engines available are the OS70 surpass, the Saito 72 the OS 70 Fl, and the new OS81. theOS55ax or the OS46 for the 2 cycle.

All in all if you check the size of engines and the power produced the 70 ultimate and the Saito 82 are the best choices with 1.2 hp for the 70 Ultimate and 1.4 for the Saito 82. The Saito 82 requires a pump separately and the Ultimate has the advantage to have it built in. They both offer you a smaller design that enable you to conceal them in the cowl and to operate them without the muffler. If you do not whant to butcher up your cowls, those are the better options.

The B-25 is such a nice plane that it deserves a little more attention. Also the Ultimate will be smaller and easy to hide and install in the cowl. The design of the cowl enable for plenty of cooling due to the vacuum action. The B-25 was also a noisy aircraft and originally straight pipe.

I would definitely keep the Ultimate's. I personally went for the Saito 82's, which require a complex installation but the result is and sound so nice!!!



Normand Ouellette

timothy thompson

My Feedback: (1)

well more rivets on the bottom ed clayman must love me! great product though. waiting for the 2s packs so i can do a final thrust test. tru turn is taking there sweet time getting parts to me but they sure take my money quick. i get my orders from flite metal lots faster and hes in tx



norman say axi 100 times and youll convert

norm

Tim,

I stayed away, I'm allergic! (LOL!)

Normand

envallm

OK. I plan to crack open my B25 kit this weekend to start building. I am away from my model at work right now, but would like to know:

1) My TF 310 came with engine mounts, does this model?
2) Where are people buying their yellow prop hubs? I dont see them when browsing the tru turn website (or tower)


Thanks

diverdon

The prop nuts are part of the kit.

Now you just need engines with the proper threads.

It comes with the engine mounts also.

Don

europatc74

My Feedback: (6)

Krprotron, Could use a little info regarding engine pitch. Installing engine covers and note a large degree of prop pitch especially the left engine. Pitches to the left. The right side is also pitched but to the right. ?????? What degree of pitch was built into the firewalls. I'm not comfortable with what I'm seeing... Anyone else notice this????????

timothy thompson

My Feedback: (1)

hey can this forum be put on the rc jet page. go read what they are saying about me. Im supposidly 12 and have no posts on here.

norm

Europact,

The angle of pitch it outward on both sides. This is TF solution to counteract the effect of a dead engine. It will help to maintain the engine in flight and avoid a sudden "yaw" and "roll" taking you to the death spiral. It will only delay it!! In my opinion letting you know you will die soon.

A gyro is certainly the better solution. I have not tried it yet but I beleive the TF system should be given a fair chance. I promess to get back to the forum on this next spring because I intend to simulate engine failure with and w/o Gyro on both sides. If you go back to the begining of this thread, I have given a detailed description of the behavior of the plane in the event of an engine failure. The propwash of both engines is diverted to the right. It will be interesting to test an engine failure on the left engine. When I simulate an engine failure it is only idling one engine and bring back the power (if it comes back) to the engine when satisfied or sufficient stress.

I beleive it will counteract the yaw but not work against the roll action due to the lift created by the wing with power and the dead engine drag to cause one wing to drop. This is why TF advise you to maintain the wing level and turn with the rudder and avoit tempting a turn with the wings.

All in all the servo on the rudder solution permits you to fly the aircraft naturally in any events and bring it back and maintain a comfort buffer between the stress you will have and a heart attack

Hellcat716

My Feedback: (2)

What is wrong with the YS 63? Has more power than the engines you have listed here and is pumped. Obviously you do not know much about YS engines.

camdyson

norm

Hello Hellcat716,

This is an interesting remark. I obviously did not mention other brands and homemade engines. The reason for this is that YS engines are not popular or supported in my area. The Area I'm from (Montreal) il listed in the top citys of the world and very little exposure to those engines. Perhaps in your part of the world you are fortunate (at least you have plenty of casinos) and have support for the YS products. They are also shy to give out specifications on their products. To the benifit of everyone on this site you should use this site to inform others of your find and let us benifit of your experience. I would be interested to find out from you the engine specifications, prop size and RPM obtained including HP produced from accessible and credible source. So far I have not found this information or a reliable dealer network to support this engine. Engines of all brands will be as good as the support you get for it. I know OS and Saito have a solid reputation. That may explain you why I shyed away from this engine. But by all means let us benifit of your knowledge.

Thank you,

Normand

krproton

Hi europatc74.

Yes, the engines have more-than-usual out thrust. If my memory serves me correctly, they both have approximeatly 4 degrees out-thrust (the right engine has 4 deg. right, the left engine has 4 deg. left) and approximately 3 degrees down thrust. This is addressed somewhat in the instruction manual when mounting the cowls--you could center the replica engine and the front of the cowl exactly on the crank shaft of the engine, but then the angle of the cowls would be objectionable. Or, you could center the cowls on the nacelles so they are pointing straight ahead, but then the engine crank shafts would be way off center in the front of the cowls and in the replica engines. Therefore, the best compromise is to partially "center" the cowls and partially angle the cowls in an attempt to conceal the engine down and out thrust.

The alternative would be to remove or decrease the down and out thrust, but we (Top Flite) felt that flight performance and the model's reaction to single-engine-out scenerios and the average modeler's ability to fly the model when this happens is more important than appearance. Previous experience developing twins and flight testing of B-25 prototypes proved that the plane handled reasonably well with either the right or left engine out with the degree of out thrust that is now built into the model.

I was not the primary test pilot of the B-25 during its development, but in flying my own, personal B-25 I simulated engine out scenerios by making one engine, then the other go to idle and flying it around for a while. Amazingly, the model didn't react suddenly or behave unexpectedly when either engine was cut--of course, I was prepared for this and the plane was at a safe altitude. The result may be different if an engine quit during takeoff. In most cases though, the first hurdle for pilots will be to realize that an engine has quit--depending on what kind of engines you are using you will probably not immediately notice that an engine has even quit--a tribute to the design. The flying section in the back of the manual goes into more detail about what to do when an engine quits.

Oh yes, to answer your question more completely, the right thrust of the right engine is to partially counteract the drag of the left wing and engine when the left engine quits and vice versa.

Of course, like normandouellette, you could also use a gyro. I don't feel a gyro is necessary, but that's just my opinion and I would never discourage anybody from using one.

Well, that's the story about the engine down and out thrust. I hope this helps you europatc74.

Tim

norm

Hello Krproton Tim,

With all respect, when you mount the engine mount it is possible to center the cowl and dummy engine on the nacelle. The engine mount is to be mounted offset at the base so the crankshaft passes through the center precisely of the nomenclature. At least this is the result I had. The engine mount pattern indicates the center of the crankshaft (has to be figured out) but once you have this indication it is possible to mount the engine mount the way you wish and maintain the center of the crankshaft. Of course on the firewall it is not in the center. It is offset so at 5.5 inch from the firewall the shaft of ccrosses at dead center!

Looking over the aircraft you see the prop outward offset and sideway the down, but when it turns I can hardly tell the color of the prop, and you do not see this. Only a beatiful B-25.

BTW I have ordered a some replacement partrs (lost turret) it is long or I'm I impatient...

Normand

Hellcat716

My Feedback: (2)

Obviously you haven't read this thread throughly.

flycast

I go along with that, unfortunately some people naturally have bad manners or really have to work at it.
Why all this pettyiness? isn't this where we exchange ideas without sarcasm
Loosen up hellcat716

europatc74

My Feedback: (6)

Krprotron, Thanks for the info. I did read the segment about working with the cowl but was courious about the opposit thrust of the engines. Back to the build......

krproton

Hi Normand!

Yes, the engine mount could be positioned on the firewall so the crank shaft would come out the exact center of the cowl and the replica engine. But then, if you mount the cowl perfectly straight-ahead, the angle between the propeller (and spinner) and the front of the cowl would be great and easily seen. What we have done is make a compromise so the cowl is partially angled and the engine is partially centered. (What am I saying--there's no such thing as "partially centered." I should have said "near centered" or something like that! [sm=bananahead.gif].) This way, neither effect is TOO objectionable--hopefully!.

Yes, the propeller and its angle relative to the cowl may be more difficult to detect when the engine is running, but in my opinion, the model must look good while it is not moving too! This is why so many people are using 3-blade propellers.

Another option would have been to angle the front of the cowl to match the angle of the propellers, but then you would have a right and a left cowl (more parts).

Tim

timothy thompson

My Feedback: (1)

ok this needs electric shift! got my tru turn hubs and painting them yellow they are a work of art.MAN I WENT ON THE JET FORUM LAST NIGHT TO ASK A QUESTION ON THE BVM F-100 AND WOW WHAT A BUNCH OF JERKS (THERE WERE SOME NICE ONES) THEY THInK they ARE GOD . i simply wanted info on that jet and I believe a good warbird pilot can transition to a f-100 the mod sided with them and pulled the thread.

diverdon

What type of paint did you use on them and what kind of prep?

Don

timothy thompson

My Feedback: (1)

reg model master and dullcote. E power means no fuel proofing. i did try to put a 16x10 on but had no clearance i cut the prop down but the tips looked bad to wide. i went with master 14x8 3 blades dont forget a drop of threadlocker on the prop adaptor and the socket screw that holds the hub on.Gas people (norman) wont have that worry. dont forget to compress the oleos and test ground clearance. pics later tonight when all is put on