rdubord

Hello,
I have a mid 90's fox 40 and am wondering what the power rating is. I have looked around and can't find it listed anywhere. I have a Tecate Biplane that is rated for a .40-.53 2 stroke. I just don't know if the fox will have the power to make the Tecate fun. It is a great running engine.
Thanks.

jeffie8696

What does it weigh?

NM2K

My Feedback: (14)

A good friend of mine flew one of the Fox .40 ABC engines in his competition fun-fly models (Coal Hauler, etc.). It never appeared to be hurting for power, but it did take a while for him to find the correct fuel for the engine. It needed a lot of castor oil to be happy.


Ed Cregger

rdubord

The Tecate is still on the building board, neither the box, plans or instruction booklet list a weight. I am guessing in the 5 to 5 1/2lbs range.

jeffie8696

If you can give us a tach readong we can calculate the expected thrust and speed so see if it is on the low or high end of the scale. Isuspect that being a FOX is will turn respectable numbers.

Hobbsy

My Feedback: (102)

http://www.foxmanufacturing.com/inde...roducts_id=290

Fox has never used hp ratings, as Jeff says, prop and rpm much better info on which to make choices.

earlwb

Which Fox .40 do you have the small crankcase design or the large crankcase design?
The large crankcase design has a flat flange bolt on carb and the small case .40 uses a square tube insert carb with two screws that lock it in from the sides.
The large case .40 is a little more powerful than the small case .40.

At first I was thinking it might work fine for it as the kit is a older design and engines from that time period would work. But I ran across a thread here: www.rcuniverse.com/forum/m_3497987/anchors_3499165/mpage_1/key_/anchor/tm.htm#3499165
where people were not very happy with it. It seems to come out on the heavy side when built, and it has problems when flying.

C185Pilot

My Feedback: (25)

The Fox 40 makes tons of power for its size and weight. Make sure that your fuel include some castor as noted above. It will fly the Tecate or similar plane just fine.

rdubord

The Fox .40 I have is the one with the carburetor held in place with a screw from each side, as in a cylinder inside the round casting in the crankcase. Not a bolt on flange style. I suppose I should pony up a larger engine, have looked at the K & B .48 and the Fox .55. I also have mixed reviews on the Tecate Bipe. Some say it is an unbalanced obese junker and others enjoyed it.
I appreciate all your help. I don't have a tach to check the rpm unfortunately.

jeffie8696

If it comes in at over 5 lbs I would probably opt for a little larger engine depending on your requirements. Are you looking for speed, power, or just put-putting around.

Sport_Pilot

With 690 square inchs and and 5 pounds it would be better to use a .60 or powerfull .50 on this plane. 

DarZeelon

Rdubord,


As others have written, rated HP numbers advertised by engine manufacturers, should be ignored in general.

Most can be considered utter lies, because as they come from the factory; set-up with the OEM muffler, the engines do not even come close to those overly optimistic numbers.
RPM numbers with given props, are most often not only believable; but can also be corroborated in your own hands.

Most manufacturers quoting RPM figures will stand by them, if the engine you received fails to produce the same numbers (or to exceed them).

Using RPM to compare engines is much more useful than printed figures.
If you want to know the actual HP output, you can use the [link=http://mvvs.nl/prop-power-calculator.xls]PropPower calculator[/link], to know the actual output @ the RPM the test prop is spun.

You will need some 'spreadsheet' SW to use it.


The actual year of production does not matter much... Since Schnürle porting was introduced, most sport engines are pretty close in power.

And in reality, a model designed for a .40-.50 engine, will most often fly more realistically, if a .25 engine is mounted in its nose...
It might not have very good vertical performance, but it will fly much like the 'real' plane it was modeled after - instead of like a grossly overpowered model.

blw

My Feedback: (3)

Overpowering helps extend that realistic performance look. Instead of shoving the throttle up and correcting for the resultant torque effects you can ease up some that power for smoother lines. It's all based on throttle management if you are looking for realistic flight. One of the reasons I would opt for overpowering is that I used to fly and I miss trim balls in our models. Being easy on the throttle is good for guessing on a trim ball you can't see.