Cougar429

My Feedback: (3)

Found out the only spare fuel fitting was M4 X 0.7, so drilled it out part way with a #30 drill and tapped it. The raised boss has more than enough meat for that. Final drill through was a 1/64, so the hole into the case is relatively small. Did the Loctite and letting it sit till tomorrow. Don't have a test stand, so will have to wait till at least this weekend to fire it up again. With the work shifts this would likely happen anyway.

You guys seem to have lots of fun with those smaller engines and love the tales of difficulty identifying make and size. I've always said Fox was underrated.

earlwb

Sounds good. But I think the hole needs to be larger than 1/64 of a inch or .015 inches. You want a good strong pulse going to and from the pump diaphragm in order to get it to flex in and out. The small hole would tend to act more restrictive and prevent the pulses from flowing easily.

Cougar429

My Feedback: (3)

Well, no problem to drill it out larger. I can run the same I.D. as the fitting.

hsukaria

http://www.valuehobby.com/airplanes.html?cat=185

codycarlisle25

Ok guys we all like our Fox Engines, but which one is your favorite?

Mine is my Fox .50

fujiman

My Feedback: (133)

HAWK .60........I HAVE SEVERAL!!!!!!!!

earlwb

I like the HAwk .60 too. I have a few of them too. This was my primary pattern plane engine years ago. The ones I used took seemingly forever to break in, but after that they were real powehouses. They are smaller than the big case modern .60 engines and a little taller than the bored out .50 size engines. I have seriously considered running one in a Jackal plane for the heck of it. Fox claims they can turn 22,000 RPMs all day long no problem. I never had one turn over 20,000 RPMs on the ground myself. My tach only worked up to maybe 20,000 RPMs at the time I did it. But the prop was too small for the Delta plane I had it on. If I remember correctly, I was running a 10x8 prop when I was flying the delta plane or was it a 9x8, I forget know.


Testing out one that I rebuilt a couple of years ago.

Cougar429

My Feedback: (3)

I guess it would have to be my first, the indestructible 50BB. Along with the 40's and new 60 have another 50 that needs a run up.

fujiman

My Feedback: (133)

i ran my Hawk .60 on a hobby shack pilot EZ .40 fw-190 with retracts. excellent combo, lots of vertical, very fast. as i remember my hawk run good pretty much rite from the get go. i ran a perry carb. with no problems!!!!!!! loved the plane, ran it into the ground at flat out speed flying just too low. but dang it just looked so good there, gear up and all!!!!!!

turbo.gst

My Feedback: (8)

Mine would have to be my Fox Eagle IV 74. Although the talk of the Hawk has my curiousity peaked about my NIB Hawk 60. Shoot, I can't have just one favorite engine anyway!

fujiman

My Feedback: (133)

the hawk was one of the top engines fox made. just my two cents worth!!!!!!

landeck

My Feedback: (1)

My favorite RC engine is the Fox .74 Eagle IV with the new carb. Of course, I do love my Fox .60 Eagle I which I have been running since 1973. My favorite CL engine is the Fox .15. The two I have have run forever.

Bruce

earlwb

The Fox Hawk .60 engine used a special finned steel cylinder sleeve that was specially hardened giving it extremely long wearing characteristics. Plus there was no resistance to the heat as it was transferred out to the cooling fins, so the cylinder sleeve was quite resistant to distortion from the heat as it was running. Barring a mishap, the cylinder is usually good for two or three ring replacements and even a new piston if need be, as it wears faster than the cylinder does. The cylinder sleeve doesn't scratch easily either. There were some numbers posted someplace about how hard the cylinder sleeve was too. But I forget where, it might be buried in this thread someplace.

Of course parts are harder to come by now. Fox has run out of the special Hawk .60 parts now. But it is easy to get bearings for them and Frank Bowman makes good piston rings for them. One could use the new Fox carb on them too.

Actually come to think of it, most all of the Fox engines run really good and are long lasting. So technically they all tend to be a favorite of mine.

Sport_Pilot

Fox .50.  I have a Fox Eagle .60 that had poor idle and transition with the Perry carb it cam with, but it runs fine on a MK-X carb, but have never flown it that way.  The Fox .50 is getting worn but still runs great.

hsukaria

So what were the reasons for Fox to replace the Hawk with the Eagle engines? Cheaper? Easier to use/break-in? etc...?

carddfann

I recently bought a brand new Hawk minus the box. Never been ran except at Fox and it has the muffler. Its their later one that has the dull colored case. I can't wait to put it in my Aeromaster Too. What a classic combo!

fujiman

My Feedback: (133)

I DON'T KNOW!!!!!!![:@] but i wish they would start up product of it again!!!!!!!!!

hsukaria

I would buy one for sure, especially with their new carb.

carddfann

I'm not sure why they came out with the Eagle series, but I have an old Sig catalog with the nice full color Fox section and it shows the 60 twin, hawk, old Duke 60, and Eagle. I think they said or infer that the Eagle was the start of a more powerful line of 60's, but basically said that the hawk was still powerful, debugged, and a good value compared to the more expensive eagles. I think Fox wanted a new generation to go more head to head with the Rossi's, Webra's, and forget that other imported high performance engine at the time. I think its name had only 3 letters in it but I'm drawing a blank. It sucks getting older. [&o]

earlwb

As I was told Duke said that the move to the Eagle II was driven by cost. Both machine time and material cost. Duke couldn't get thick walled tubing material for the Hawk so he machined the cylinder from solid "Rod" stock, this was expensive. The Eagle's cylinder could be made from tubing this saved a lot in machine time and material costs. At this time electron beam welding had been perfected. This allowed Duke to make his crankshafts from three pieces that he was then able to electron beam weld together. Even though he had to send out the cranks to be welded the cost savings in material and even the machine time to rough out the cranks from solid bar was worth it. (I never heard of a Fox Eagle II, III or IV crank breaking at any of these welds).

Now Duke's actions weren't totally driven by cost. The Eagle II and III were built with 3 piece cases this allowed Duke the flexibility to make his 120 twin from the same basic modules. The 3 piece case had matched front and rear housing with precision bolts bolt holes that were match machined. Once the life of the 120 had come to an end there was no need for this time consuming machining operation. This is where the 2 piece Eagle IV came from and it's great 17mm crankshaft. The 120 was a failure in the market place because of the uneven cylinder charging from the crank pin's action against the transfer ports. A rear exhaust Fox 120 is a very powerful and reliable twin!


Hey cardfan, the big time pattern .60 engines were OPS, Rossi, Webra, HP, and OS. Fox was sort of a left out child for odd reasons. When i was pattern flying I was the only one using Fox engines everywhere I went. But earlier the Fox .60 Blue Head engines were quite popular until the planes needed retracts and more speed.

hsukaria

So, by saying that the Eagle had more power, yet the Hawk could turn a lot higher RPM's, would that mean that the Eagle can turn a bigger prop due to higher torque?

Anyway, the Eagles are good about being able to set them as rear exhaust. But how much power, if any, is lost if the exhaust is set to the rear?

carddfann

Thanks Earl. OPS was the 3 letter company I couldn't remember. I have some old 80's RCM magazines where Fox put out some large page adds and one of them had a chart showing how their new Eagle compared to those imports at a lower price based on their own testing. It was sort of funny how their matrix had some blanks as if maybe some results didn't turn out in their favor so they just didn't publish it. Who knows. I'm signing off for the night. I'm about to fall asleep.

earlwb

Actually, technically the Eagle IV engines with the larger stronger crankcase and larger crankshaft is the better engine to have. The Hawk .60, the Eagle II and Eagle II crankcases start to flex or move when you rev them over 18k which causes problems. The Eagle IV doesn't have that problem.
But actually trying to rev over 18k doesn't seem to gain any more power. The Eagle IV develops more power than the Hawk does and it is more powerful than the Eagle II and III engines as well. The Eagle IV engines with their moveable cylinder (so you can change where the exhaust exits, and the head button that you can change for different combustion chamber shapes makes the engines much more versatile. Plus you can even get a reverse crank for them if you need it too.
I mention the Hawk .60 as I have fond memories of how well the engines ran many years ago. So I tend to like it still a lot.

earlwb

Konrad discussed Rear Exhaust engines here in his blog.
http://www.rcgroups.com/forums/member.php?u=4229

The main advantage is streamlining. the tuned pipe is behind the engine and typically enclosed so the airplane slips through the air with less aerodynamic drag.
For pattern planes the added side surface area helped to make knife edge and other maneuvers better too as you had more side area for lift then. For pylon racing it was all streamlining.

Sport_Pilot

They didn't replace the Hawk with the Eagle. They sold 60 sized engines in the Hawk, Eagle, and Falcon brands side by side. The other two were phased out and only the Eagle remained, but the Eagle II became Schnuerle ported.