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#1 cale10 Jun 28, 2012 05:23 PM

general engine discussion thread
 
i figure id strat this thread to help other people just so they can ask questions and get answers about ANY engine. so talk it up.

question 1 what is the GAS equivelinent to a .61 nitro?

#2 earlwb Jun 28, 2012 05:25 PM

A 15cc to 17cc gas engine, but some guys wanting extra oomph go with a 20cc gas engine too.

#3 cale10 Jun 28, 2012 05:35 PM

talk it up

#4 ahicks Jun 28, 2012 05:49 PM

Quote:

Originally Posted by earlwb (Post 22023949)
A 15cc to 17cc gas engine, but some guys wanting extra oomph go with a 20cc gas engine too.

Just went through all this picking out power for a new plane -

I think the 17 weighs the same as a 20? If that's true and you're packing the same weight either way, you might just as well have the power of the 20?

The RCG/RCGF (whatever!) 15cc are 5.6 oz lighter than the 20's, but you also drop a significant amount of thrust - to just less than 10lbs. That's a struggle to justify there! I suppose if the lighter engine meant the difference between gas or nitro, I would have to go gas!

I ended up going with a 20...

The 9cc though. Still waiting to see more of those in the air. Earl's bearing and the fuel problems have me in "wait and see" mode. -Al

#5 Gary Cee Jun 28, 2012 08:42 PM

There are several other factors to consider aside from weight to thrust or power numbers. Not everyone yet is hanging their planes on the prop . It is nice at times to fly on the wing .
High lift/high drag planes like Cubs , Kadets , Telemasters etc fly fine on a little less power and don't really respond to higher power in a linear manner . Seems we all start out trying to stuff the most horsepower of a given size engine family into the plane . A little later we learn to appreciate some of the less measureable aspects.
The larger engines in a given size range often shake more and burn more fuel to boot . It is more than the common "That's what the throttle is for response. The Saito .82 is "just a bit bigger" than the .62 but the sweet running .62 is just right for so many plans where the .82 would just abuse the airframe without a real, useable gain in flight performance . I recently pulled a Saito .72 out of a 72 inch span Paulistinha and put a .56 in it's place. The plane flys great and the difference in performance is not all that great .

The 3D world is a different world however .

Just a few thoughts ..YRMV

#6 I TOBOR Jun 28, 2012 10:23 PM

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Gary, I'm one of those guys that matured beyond using the biggest engine, the Saito .65 I got from you is the perfect example. I installed it in an Alpha 60 that I used to fly with a Saito 1.00, I had to sell the 1.00, the .65 will fill its shoes just fine. I power my RCM 40 with a Saito .40 instead of a ..56 etc. Most would say the the Alpha 60 requires a .90 fourstroke, I'll bet the .65 flies it just fine.

#7 datsunguy Jun 29, 2012 12:23 AM

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Most airplanes today are grossly overpowered and fly on the prop not the wing. Example: The original falcon 56 recommended a .19 but today guys are flying that airplane with a .40 or bigger. It flew quit well with a 19 even with the heavier radios back then.

My Goldberg Cub flew very realistically with an old Saito 40 with the bolt on head. Used the same engine on an ACE 4-40 with great results until the wing came off on a low pass. Very exciting.

#8 EloyM Jun 29, 2012 12:31 AM

You might start by dropping that "nitro" business. Nitro is not the fuel, it is an additive, and actually is not used in all fuels. If you must refer to engines by the type of fuel used, remember that the highest percentage of a glow engine's fuel is alcohol. Methanol, to be exact.
On the other hand, thanks for referring to them as "engines", and not as "motors"..

#9 earlwb Jun 29, 2012 06:47 AM

Many many many years ago, I flew a Falcon .56 using a OS Max .35 engine. It flew great like that and seemed to have more power than I needed. But way back then, no one had thought of 3D flying or hovering, etc. That was back during my beginner days, If I remember correctly, the Falcon was my first aileron plane.

#10 Gary Cee Jun 29, 2012 07:26 AM

Nowdays a beginner would strap a Saito 100 on a Falcon 56 with the intentions of hovering it....on the first lesson. :D
Five years later he may find himself with a nice Cub and a Saito 50 ;) (After learning to fly)

#11 epoxyearl Jun 29, 2012 07:39 AM

I love how you guys talk-me,I'm flying a 9' Cub with an OS.91 4 stroke,14 x 6 prop, -on the wing-the most fun I've ever had with a model airplane.-Just took me 50 years to learn that though.
My Astro-Hog built from original 1958 plans still has a .35 in it.I need to make a new tailwheel assembly,from a tin can,-remember that?,stab rubber banded on the bottom?

#12 Taurus Flyer Jun 29, 2012 08:43 AM

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OS Max 0.35 FP, enough power for "full house" pattern flying.

Ed Kazmirski's personal contest Taurus (4 min 16 sec)


The redesign and reconstruction of this Oldest Taurus on Earth was a project to bring back the famous unique first succesfull Taurus of Ed Kazmirski. Ed did compete with this Taurus in 1961.

There was a photograph of the crate Ed had with him in Rhodesia, on which this Taurus was visible. Studing documents of the past I could trace back this Taurus to spring 1961.

In the past this Tauus was followed by the first commercial Taurus of Ed Kazmirski, plans were distributed, and that Taurus is called the "Frank Myers Taurus", Frank did make the drawings in December 1961, later, 1962/1963 the world famous Top Flite Taurus. was "born":

Span? 68 / 70 inch! Engine Greenhead with plain bearings.
I use the OS Max FP/

For the project, see.

http://www.rcuniverse.com/forum/m_7950207/tm.htm

Taurus Flyer

#13 ahicks Jun 29, 2012 08:53 AM

Quote:

Originally Posted by datsunguy (Post 22027129)
Most airplanes today are grossly overpowered and fly on the prop not the wing. Example: The original falcon 56 recommended a .19 but today guys are flying that airplane with a .40 or bigger. It flew quit well with a 19 even with the heavier radios back then.

My Goldberg Cub flew very realistically with an old Saito 40 with the bolt on head. Used the same engine on an ACE 4-40 with great results until the wing came off on a low pass. Very exciting.

Because they can "fly on the prop" does not necessarily mean they can't "fly on the wing"! I believe a carefully chosen plane/power combination, especially one using gas for power, SHOULD be able to do both reasonably well! Most 3D planes are good examples of ones that will do that, some much better than others. Taken to the extreme, the wing loading on some of the profile type 3D planes approach that of a glider's? They fly EXTREMELY well when flown "on the wing"!

What's the down side of flying something "grossly over powered" like that "on the wing"? Because it's capable of hovering does not mean it won't fly great when flown as a sport plane. Just me, but a plane capable of flying with an expanded speed envelope (walking speed to 100 or so?) is something I look for any more. Totally spoiled....

#14 Reginald Jun 29, 2012 09:37 AM

Quote:

Originally Posted by datsunguy (Post 22027129)
Most airplanes today are grossly overpowered and fly on the prop not the wing. Example: The original falcon 56 recommended a .19 but today guys are flying that airplane with a .40 or bigger. It flew quit well with a 19 even with the heavier radios back then.

My Goldberg Cub flew very realistically with an old Saito 40 with the bolt on head. Used the same engine on an ACE 4-40 with great results until the wing came off on a low pass. Very exciting.

Could'nt agree more. I see Piper Cubs taking off on shows climbing straight away in vertical position. If you did fly in Cub's like myself you realize how ridiculous that is.

#15 Reginald Jun 29, 2012 09:41 AM

Quote:

Originally Posted by earlwb (Post 22028353)
Many many many years ago, I flew a Falcon .56 using a OS Max .35 engine. It flew great like that and seemed to have more power than I needed. But way back then, no one had thought of 3D flying or hovering, etc. That was back during my beginner days, If I remember correctly, the Falcon was my first aileron plane.

Was my first full multi too. It was a nice floating airplane. We learned the hard way that, when overpowered, it was prone to aileron flutter, cured that by adding more hinges, that solved the problem. I believe mine was powered with
the same engine.


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