NM2K

My Feedback: (14)

I talked Duke (via telephone) into making a high compression head available for the Fox Eagle .60, version 1 of the Eagle .60 series.

Back in the olden days of the seventies and the very early eighties, All Fox R/C engines were set up to run best when burning Fox Missile Mist 25% nitro fuel. It's a fact, just look over the old (seventies) owner's sheet.

I couldn't afford to burn Missile Mist with me flying as much as I was in the lower pattern classes, and I told Duke that it would nice if he would offer a high compression head for the Eagle .60 so that I could get a decent idle and transition while burning 5% nitro fuel. Within a month or two, the new head was being advertised and offered for sale.


Ed Cregger

earlwb

NM2K, that is just so weird. I was running 5% nitro Fox fuel in all my Fox engines since the first time I got one. I do not remember idling being a problem. My recent video clips of me running the old Fox Blue Head was done using 5% nitro glow fuel too. Over the years the fuel brand may have changed but it was 5% for the most part. Now when pylon racing I used Missle Mist or whatever the club hosting the race provided. I used Missle mist in the old Fox 049's and 07's though.
One of these days I'll have to put my high compression head on a engine and see what it does. I never tried it as of yet.
But I do remember Fox mentioning Missle Mist for the ultimate in performance in his engines though.

earlwb

Yes that is correct. But you usually have to ream out the prop anyway. So it goes out one more hole size.
Anyway it is worth a thought, if you have issues.

earlwb

I took pics of a old Fox Flyer, circa 1989, for their engines and accessories. Since the pics are big, I left them as links, so if you had a slow internet connection, it doesn't overwelm you. But they have a lot more information on their engines than the current Fox website provides.

http://i248.photobucket.com/albums/g...d_Flyer_01.jpg

http://i248.photobucket.com/albums/g..._Flyer_01a.jpg

http://i248.photobucket.com/albums/g..._Flyer_01b.jpg

http://i248.photobucket.com/albums/g...d_Flyer_02.jpg

http://i248.photobucket.com/albums/g...d_Flyer_03.jpg

http://i248.photobucket.com/albums/g...d_Flyer_04.jpg

http://i248.photobucket.com/albums/g...d_Flyer_05.jpg

http://i248.photobucket.com/albums/g...d_Flyer_06.jpg

hsukaria

Good to know about the piston ring seating. Thanks.

earlwb

On the Eagle III's that Mr Fox modified for me, he was concerned about the ring ends getting caught in a port. So since I was the first flyer to want rear exhaust engines, he wanted to modify the engines for me to ensure it would work out OK. This all happened when i was talking with him when i was visiting his factory way back circa 1978, I bought the two engines and left them with him to modify for me, and he mailed them out to me a week later.
I didn't have any problems with the engines he modified. but I honestly don't know it the ring ends would get caught in a port or not. But it might be worth thinking about and watch for if you build one up as a rear exhaust engine. I have other engines where the ring ends are exposed in the ports and they aren't having any problems.

Honestly, I think i was the only flyer to use rear exhaust Fox engines. For some odd reason I never heard or or encountered another flyer using Fox engines in a pattern plane.

hsukaria

It will be a while before I attempt to rotate the cylinder, maybe I won't do it anyway. I am installing this engine as is with the normal side exhaust on an existing airplane. I was just thinking for the future. But I wonder, if I rotate the cylinder with the piston still in it, would the ring rotate with the cylinder or stay in place. I guess it would have to do with which side of the piston ring has higher friction, the cylinder side or the piston side. I imagine the cylinder side of the ring should have a lot lower friction, so the ring will stay in place. (I don't have experience in this area).

Konrad

It is not recommended to rotate the cylinder after break in. The Piston to Cylinder side loading (rubbing) changes along with the thermal characteristic (the cylinder above the exhaust port gets hotter).

Select the configuration you want prior to break in and then leave it for the life of the engine, unless replacing the ring and cylinder.

hsukaria

Ok, I will actually get to start the engine soon as is in a few days. I will get some low nitro fuel wit Castor as mentioned before. I won't be rotating the cylinder for a long time anyway.

Konrad, do you mean that the cylinder liner needs to be replaced with the ring, or the actual cylinder (upper part of the crankase)?

Konrad

If changing the configuration of the engine after break in you should replace both the cylinder insert (steel) and ring to allow them to both re-bed into each other as the forces and location of these forces will have changed between the side and rear exhaust configuration.

hsukaria

Ok, thanks Konrad.

jessiej

[/quote]Also those that needed crankcase pressure to run, could out run the prime before the fuel started to flow. I'm staying away from high performance engine with my statement.
[/quote]

I have had a number of CL combat and rat race engines that used crankcase pressure. All started by hand quite easily.

jess

Konrad

Timed crankcase pressure? Yes, they could and did start by hand. It just often wasn't a reliable starting method. In most of the classes I competed in, reliable engine operation was paramount! Now my FAI F3D pylon engines would not start by hand, but then again I can't say as I really ever tried to get them to start on a hand flip.

All the best

93octane

My Feedback: (9)

Any body got the specs for the FOX 78 rc...not much talk about them..Have an almost new one..wondering what to use it on

earlwb

here you go, the Fox 78 was designed to turn big props at a decent RPM. But it does turn a 13 incher better than the .60 blue head at the time. You can look up the specs on some of the planes mentioned in the ad to get an idea of what to run it in. at the time there were likely using Topflight or Rev-Up props, so you may not be able to match the actual RPMs FOX was advertising from back then. Missile Mist fuel is also 20% nitromethane and 20% castor oil. Nobody used mufflers back then either.

Konrad

Model Airplane News has a write up on the last model of the 0.78. It even had the plots of the power curve in it. I found it interesting that its contemporary brother the Eagle III 60 had more power.
Also an interesting note; Duke did made a reverse crankshaft for this 0.78. (I think I posted a photo of the crank http://www.rcuniverse.com/forum/fb.asp?m=10052565 http://www.rcuniverse.com/forum/fb.asp?m=10054503 ) It was a great engine for model twins like the Bud Nosen Cessna 310.

Duke was still very upset (1986) about the AMA imposing the 10cc limit on pattern right when he came out with this engine.

earlwb

Konrad, I think you meant the Fox Eagle .74 engine not the .78. By the time 1986 rolled around, I don't think he was producing the .78's anymore.
 Fox put out the .74 Eagles and then the AMA restricted the pattern classes to a 10cc engine displacement limit.
I remember he was quite upset about it.
But then the US government with DOT also killed his bicycle engine system, by regulating it out of existance. So that market evaporated overnight. I think he was even stuck with quite a few built up units too.

Konrad

The AMA imposed the 10cc limit in the early 60's (I think). Duke last upgraded the .78 in the early to mid 80's with the Mk X carb and a nod to lower nitro fuels and a tear drop muffler and blast finish. This was all before the Eagle IV series late 80's which brought us the Eagle IV .74. I bought my last .78 with reverse crankshaft from Duke in 87.

Duke claimed that it took him several years to financially recover from the design of the .78. As he put a lot of work into it thinking that a good R/C engine with an automixture carb would sell like hot cakes to the pattern guys! Well, with the 10cc limit there were no sales to the pattern guys. This 10 cc limit gave the european OEMs a head start over the American manufactures as they had developed some 10cc pattern engines for the FAI F3A class. I don't think any American engine made much head way into pattern other than the K&B 61. And then it needed to be a Lee Custom.


Edited: to add blast blast finish

w8ye

My Feedback: (16)

Konrad, can you substantiate these dates with dated advertisements etc?

Konrad

What dated advert?
I don't claim to be an historian. So the exact dates may very well be off but the chronological order is correct (for the most part). The baffled .78 had a very long production time line.

NM2K

My Feedback: (14)

My interest in pattern flying began in 1968. At that time the 10cc displacement limit was already standard throughout the US and the rest of the world (that I was aware of), except for some lower classes in some countries where 6.5 or 7.5cc was the upper displacement limit. I can't remember which it was these days, but it was one or the other.


Ed Cregger

Konrad

I thought the AMA 10 cc limit came into being around 67, but I don't know this as a fact. Nor do I know when the Fox 0.78 first came out. I didn't start flying R/C competitively until 81. But then there is a lot of debate that I ever flew competitively [>:]

I did find this about the 1964 FAI ruling in the introduction
http://www.rcmplans.com/issues/reque...091984-1-1.pdf

All the best,

earlwb

Thanks Konrad, my memory wasn't as good as yours in this area.
So in the eary 1960's the restrictions were FAI at first restricted F3A to 10cc and shortly thereafter so did the AMA.
Fox had made the .74 using his new big crankcase, and his market evaporated when the AMA did the 10cc limit in the early 1960s.
So then Fox made a .60 using the same crankcase of which I have a example but it wasn't all that popular for one reason or another, And later Fox bored out the .74 to make the .78 using the same crankcase.
its too bad be didn't go ahead and make and sell the .90 with a better rod for the airplane folks.

I think what I remembered was around 1982 when the FAI decided to allow 20cc four stroke engines to compete against the 10cc two stroke engines in F3A pattern. The AMA then shortly followed suit. That pretty much killed off everyone using 10cc engines in pattern. of course that caught all the 4 stroke engine manufacturers off guard as they were all coming out with special .90 engines for pattern as they thought the FAI would approve 15cc four strokes as OK for pattern.

Konrad

I too tried the 1.20 in pattern, with the Condor 1.20 and the Saito 1.20 big head. I quickly learned that it still couldn't beat a properly set up 10 cc two stroke. I think in this thread I mentioned that I could set up the Eagle III as a Hanno killer. While that was true I still preferred the Webra Red head as my pattern engine. I thought that Hanno and Hyde used two strokes for their FAI title wins. I often wonder how many FAI F3A titles went to the four cycle during the engine displacement limited area.

The four cycle was heavy, expensive, and still not as powerful as it should have been. It wasn't until the YS came that we saw a good four cycle. Yes, I loved the Enya R 1.20 and the Saito for sport flying. But sport flying is far from being as demanding as a competition set up. After all it is competition that improves the breed.

I have to say I liked that Enya taught OS that there was a market for a performance 4 cycle. OS's philosophy at the time was that the four cycle was a "Sunday" type engine. So without the FAI 20cc limit we wouldn't have so many fine sport engine without broom sticks for cams (they now have some lift and duration).

All the best,


Konrad

blw

My Feedback: (3)

Can you substantiate that claim?