Old Fox 25

[Tom Perry]

Hey Bill Little,

You are always refering to your old 3 bolt fox .25 as a '57.  Are you sure it isn't the '54 model? 

I'm refering to the one that is a punched out .19 and also came out as the .201.  Mine have what looks like a ground out circle with 25 stamped in it.  They also have impressions in the intake that looks like it could be drilled for another NVA.

I will send a picture later if I get a chance. 

[Bill Little]

Hey Bill Little,

You are always refering to your old 3 bolt fox .25 as a '57.  Are you sure it isn't the '54 model? 

I'm refering to the one that is a punched out .19 and also came out as the .201.  Mine have what looks like a ground out circle with 25 stamped in it.  They also have impressions in the intake that looks like it could be drilled for another NVA.

I will send a picture later if I get a chance. 

That's the one, Tom.  I have just always heard them referred to as '57 models.  Either way it is the one you are talking about.

Lighter than the .35,and .19, (.29 sleeve and piston in the machined out .19 case) and has about the same grunt as a stock .35.

Bill <><

[Bob Kruger]

Hey Bill Little,

You are always refering to your old 3 bolt fox .25 as a '57.  Are you sure it isn't the '54 model? 

I'm refering to the one that is a punched out .19 and also came out as the .201.  Mine have what looks like a ground out circle with 25 stamped in it.  They also have impressions in the intake that looks like it could be drilled for another NVA.

I will send a picture later if I get a chance. 

Tom;

Back when the size of engine made a difference in meets, e.g. class 1/2A, A, B, C, etc., engine displacement was used as the discriminator in differentiating model classes in contests.  This is most certainly a legacy of powered modeling's free flight roots.  If you look at Berkley kits from the 50s, the boxes declare "Class B Control Line" or "Class C Control Line", etc. 

For the most part, discriminators based on engine size in CLPA no longer exist with a few exceptions, e.g. 1/2A events, P40, and the possibly some of the old WAM rules that  may still be used in some West Coast events.  But, back when engine size was important, and there was a larger FF population as a sample of the modeling community,  Duke Fox was given a unique challenge when the size differentiation between Class A and Class B changed for a year or two.  I don't know if Duke changed bore or stroke, or just changed the number stamps on his Fox 19 cases, but the Fox .201  was born.  The change in AMA rules was short lived, and when the specs for Class A went back to their previous numbers, the case numbers were changed back to "19."

The Fox 19s  marked the 201 were only made for a year or two.  But, it is the Fox 19 or very close to it.  The Fox 201 is not the Fox 25, even though they are based on the same case.  The 3 bolt backplate Fox 25 has a different piston/sleeve.  As Bill said, they are  great engines.  I never found them to have all the guts of the Stunt 35, but they were close.  My 25s like the old TF 9-6 props.  Don Still used them on his Stuka, so that dates them back quite a ways into the early 1950s.  However, like the Stunt 35, I am sure that there were a few updates it went through.  Regardless, personal experience gives me the opinion that they are great engines if you can find one and perform well on 5% and 10% nitro, and all castor fuel.   Possibly with higher nitro fuel you can swing a little more prop, e.g. a 9.5-6, but as parts are hard to come by, I am pretty conservative on the load I put on mine.

Good luck with yours.

V/r

Bob

[Tom Perry]

Bob,

The 25s I was referring to are not new to me.  I've had them for at least 40 years or so.  I have always agreed with Bill that it is an outstanding engine.  I saw another post from Bill lately where he mentioned his "57 fox 25"  I just wanted to make sure he and I are on the same page when talking about it.

Now that I am able to build some very light Ringmasters I will be flying them again and think they will do really well on that plane.  I have enough 9/6 props to last me for quite a few crashes but have recently acquired some 9/5 power point props to try.

What I've always liked about the .25 is the power to weight ratio.  I really don't know of any .25 engine that weighs less than the 54 Fox.

Here is a list of some of the older Fox engines that I purloined from somwhere on the web and it is helpul on identifing some of the older Fox engines:

'49 "35" .352 glow - sand cast, no markings on engine.  
'49 "29" .299 glow - sand cast, “29" stamped on exhaust stack
'50 “Racing Special" .299 glow - sand cast, big ports
'50 '59 Stunt' .599 glow - large downdraft venture with smooth back  
'51 "59" .599 glow - smaller downdraft venturi with indented end
'52 “29” .299 glow - die cast case
'52 "35" .354 glow - die cast case  
'53 "19" .198 glow - complex split crankcase, square venturi
'54 "19" .199 glow - conventional design case
'54 "59" .599 glow - front rotary valve  
'54 "25" .257 glow - bored-out 19, "25' on spotface on bypass
'54 "19 2-Speed" .199 glow - twin needle valves
'54 “25 2-Speed" .257 glow - twin needle valves
'54 "35 2-Speed" .352 glow - twin needle valves  
'54 "59 2-Speed" .599 glow - twin needle valves
'56 “29R" .-299 glow - huge intake, twin glow plugs
'56 “29R" .299 glow - huge intake, single glow plug
'57 "Combat Special” .353 glow
'57 "19" .199 glow - splined shaft & prop driver
'57 "19" .199 glow - speed control via exhaust throttle
'57 “25” .256 glow - speed control via exhaust throttle
'57 "35" .352 glow - speed control via exhaust throttle
'57 "59" .599 glow - speed control via exhaust throttle
'57 “19” .199 glow - wide mounting lugs
'57 “25” .256 glow - wide mounting lugs
'57 "35 Stunt" .352 glow - red painted head
'58 "Black Head Special" .352 glow - black painted head
'58 “15” .145 glow
'58 "29X" .299 glow - head screws go thru cylinder fins
'59 "Rocket .099" 008 glow
'60 "59 Mark IV" .599 glow - ball bearing shaft
'60 "Combat Series lll" .352 glow - removable case front cover

I'm not certain but I think the 54 two speed shares the same case.   

[Bob Kruger]

Tom;

Great list!

I didn't see the .201 on it, but like I said it was only produced for a year or two at most - and then only to make the Fox 19 fit into the change of the ruling for Class B displacement. 

All of the three bolt 25s that I have owned have/had gussets on the case - something that Fox continually added to his engines during the 50s and 60s.  I suspect the differece between the '54 and '57 Fox 25s was most likely mods to the cases.  While the displacement on your list differs by .001 between '54 and '57, I have to wonder if that is a typo on the part of the person who compiled the list, or possibly the person as the factory doing the spec sheets. 

My experience with the three bolt 25 is not as long as yours.  One of my father's partners game me his from when he was a kid in 1971, and it soon went into my first Ringmaster.  I always thought it an ideal mix.  I have no idea as to the weight was back then, but considering  back then I kept finishes minimal, so I figure somewhere in the high 20s.   Regardless, between that engine and an OS Max 30 alternating in various ships  I learned the AMA pattern.  I will bet that a Ringmaster weighing between 19 and 23 ounces using the Fox three bolt 25 will be a true pleasure to fly.

Please - let us know how the light Ringmaster and Fox 25 turn out.

V/r

Bob

Bob,

The 25s I was referring to are not new to me.  I've had them for at least 40 years or so.  I have always agreed with Bill that it is an outstanding engine.  I saw another post from Bill lately where he mentioned his "57 fox 25"  I just wanted to make sure he and I are on the same page when talking about it.

Now that I am able to build some very light Ringmasters I will be flying them again and think they will do really well on that plane.  I have enough 9/6 props to last me for quite a few crashes but have recently acquired some 9/5 power point props to try.

What I've always liked about the .25 is the power to weight ratio.  I really don't know of any .25 engine that weighs less than the 54 Fox.

Here is a list of some of the older Fox engines that I purloined from somwhere on the web and it is helpul on identifing some of the older Fox engines:

'49 "35" .352 glow - sand cast, no markings on engine.   
'49 "29" .299 glow - sand cast, “29" stamped on exhaust stack
'50 “Racing Special" .299 glow - sand cast, big ports
'50 '59 Stunt' .599 glow - large downdraft venture with smooth back   
'51 "59" .599 glow - smaller downdraft venturi with indented end
'52 “29” .299 glow - die cast case
'52 "35" .354 glow - die cast case   
'53 "19" .198 glow - complex split crankcase, square venturi
'54 "19" .199 glow - conventional design case
'54 "59" .599 glow - front rotary valve 
'54 "25" .257 glow - bored-out 19, "25' on spotface on bypass
'54 "19 2-Speed" .199 glow - twin needle valves
'54 “25 2-Speed" .257 glow - twin needle valves
'54 "35 2-Speed" .352 glow - twin needle valves   
'54 "59 2-Speed" .599 glow - twin needle valves
'56 “29R" .-299 glow - huge intake, twin glow plugs
'56 “29R" .299 glow - huge intake, single glow plug
'57 "Combat Special” .353 glow
'57 "19" .199 glow - splined shaft & prop driver
'57 "19" .199 glow - speed control via exhaust throttle
'57 “25” .256 glow - speed control via exhaust throttle
'57 "35" .352 glow - speed control via exhaust throttle
'57 "59" .599 glow - speed control via exhaust throttle
'57 “19” .199 glow - wide mounting lugs
'57 “25” .256 glow - wide mounting lugs
'57 "35 Stunt" .352 glow - red painted head
'58 "Black Head Special" .352 glow - black painted head
'58 “15” .145 glow
'58 "29X" .299 glow - head screws go thru cylinder fins
'59 "Rocket .099" 008 glow
'60 "59 Mark IV" .599 glow - ball bearing shaft
'60 "Combat Series lll" .352 glow - removable case front cover

I'm not certain but I think the 54 two speed shares the same case.   

[Bill Little]

Hi Guys,

AFAIK:  The Fox 25 (19 case) was the same from '54 -'57.  All th eparts are listed by Fox as the same.  The "2 needle" case stayed, as it did with the 19, even when the R/C part changed.

Evidently, the Fox .201 was simply a "displcement change" for he .19 as I can find no different parts numbers for them.
Fox spotted the 19 on the case and stamped .201 as they did the .25.  No piston/sleeve change for the .201.

From what I've learned, the .25 used the stunt 29 sleeve and piston in a machined .19 case.  Ty has tried to use that combo on a .19 but I don't recall if he ever finished the project. (??)  I guess the inner diameter of the .19 case must be relieved a touch.  That would not have been a problem for Fox, and the 25s seems to have been a small run in the years they were produced.

I am using GMA Custom (petal) 9X6 props on mine, but the old paddle blade Top Flite 9X6 and 9X5 work real nicely , too.

We're all together on this one! 

Bill <><

[Tom Niebuhr]

My one and only Ringmaster, in my learning days had that great Fox .25. I also used it in an airplane of my own design that I flew in Senior at the "61 Willow Grove Nats.

I have 2 of them now that are like new. I had one in the Frisky Pete that I had at VSC several years ago.

The .25 runs like a .35, 1 or 2 flip starts, and much stronger than the .19

Just a great little engine.

[Tom Perry]

Here are the pictures of the '54 Fox .19, Fox .25.  A Fox 29 is included in one of the pics just for comparison purposes.  I don't know what year but would guess late '50s

Notice the indentations in the intake above the NVA.  This same case was used to make the '54 two speed engines with the two needle valves.

I have one of the .201 engines somewhere also but can't put my hands on it right now.  I'm sure it was More important to the free flight people than the control liners.   

To go along with the list I posted earlier here is a link to the Fox combat engines starting in '57:   

http://www.clcombat.info/foxhistory.html

[Bill Little]

Hi Tom,

I dug out my instructions for my NIB .25 and it is a '57 version.  All mine have a "web" under the crankshaft housing like the picture of your .19.  (which makes me think your .19 is a '57)

My .19 does not have the web just like your '54  .25 (which makes me think my .19 is a '54)

Either way the only differences between the years.versions are the crankcases.  All the other part numbers are the same.

First two pictures are the NIB '57 .25.  The other picture is the grungiest one I have which runs like a fine Swiss watch!  (I think it is finally broke in!)  BTW: the instructions call for a mix of Superfuel and "High Nitro" fuel for the .19 and .25.  The .201 is not shown in the '57 literature.

Bill <><

[Bill Little]

Picture, maybe??

Here goes.........

The one with the Froom spinner is going into my Mackey "Bluebird", a shrunken Mackey "Lark", which IIRC, was published in 1957.  I *hope* to have it finished for Oct. Huntersville.  In the painting stages now.

Bill <><

[Bill Little]

Picture 2

[Bill Little]

Picture 3

[Tom Niebuhr]

Bill,

Your .25 is definitely the more recent version of the old .25, Note that the case also has the  beef up that shows between the fins, looking like extensions for the head bolts, The .35s also had this material added about the same time.

[George]

I have an old Fox .19 that I got used from a friend in ~1957. It has no webbing and I'm not sure of it's year. My friend gave me a .25 piston/cylinder along with it that I found out a few years ago I couldn't use. My engine has a rounded piston baffle and the .25 piston had a flat baffle.

The fact that I could not use it was pointed by a fellow who needed just that set so I gave it to him.

Point of discussion (finally) is that the cylinder on the .25 set was very thin. It may have fit a .19 case without altering the case.

George

[Tom Perry]

I wonder if any of the users of this forum have a copy of the Model Engine Encyclopedia.  At 49.95 plus 4.50 shipping it is a little too expensive for me just to answer the questions we have on these Fox motors.  If someone reading this owns the Encyclopedia and is willing I would love to see a review of it in the review section.  A plus would be letting us know if we are correct in our assumptions of the years we think the motors were manufactured.

I think I'm fairly safe in my belief that the 19s and 25s without the web under the front of the crank case are '54 models and the ones with the web are '57s. 

I learned a lot from this discussion and appreciate everyones comments.  I'm also glad to see that there are still some modelers that run the so called collectors items.  I think it's kind of neat to get a 4/2/4 run from a .19 or .25 engine. 

[Bill Little]

I wonder if any of the users of this forum have a copy of the Model Engine Encyclopedia.  At 49.95 plus 4.50 shipping it is a little too expensive for me just to answer the questions we have on these Fox motors.  If someone reading this owns the Encyclopedia and is willing I would love to see a review of it in the review section.  A plus would be letting us know if we are correct in our assumptions of the years we think the miters were manufactured.

I think I'm fairly safe in my belief that the 19s and 25s without the web under the front of the crank case are '54 models and the ones with the web are '57s. 

I learned a lot from this discussion and appreciate everyones comments.  I'm also glad to see that there are still some modelers that run the so called collectors items.  I think it's kind of neat to get a 4/2/4 run from a .19 or .25 engine. 

Hi Tom,

I do like the "vintage" Fox 19 and 25 which do such a greatr 4-2 Stunt run.

The parts sheet in my NIB engine does identify the carnkcase as being specific to the '57 Fox .25, so 1957 has to be the year those crankcase "mods" were introduced. 

Maybe I can scan the material tonight.

Bill <><

[James Lee]

I just put a note about the model engine encyclopedia in the review section...   

without going into a lot of detail, the last post about the 19/25 engines is fairly correct...  teh 1954 vinatge ones did not have the support webs at the crank nose, those coming in at 1957.  The webs were added to the 29/35 in 1955 and 1958...   lots of detail changes over the years.   the 25 is a real interesting engine...   The sleeve is VERY thin...   with the 29 bore in a 19 case...  I have never checked to see if the 25 piston is the same as the 29... f The bore is the same, but I dont know if the wrist pin is in the same place and whether the skirt length is the same.  Also, since the sleeve is so thin there is minimal sealing area at the top flange, so...  the flange has a ridge that fits into a groove in the head, and the head gasket is  very narrow.

Trying to figure out Foxes will drive ya nuts!!!   Plus on the 25's there are different innards depending on the phase of the moon.....

Hope this helps settle some of the mud...
Thanks
Jim       

[Bill Little]

Thanks, Jim.  I hope all is well with you!  PLease, LMK if you are coming this way (East!) anytime soon. 

I need to give ol' Todd a call again. 

As an aside, I loaned out the "corrected" Formula S plans and haven't got them back, yet.  That is always a great looking stunt ship, IMHO.  It presents very well.  I have th echoice (when I get the plans back and actually build one) of using a T&L Red Head 40 or a T&L ST 46.  I believe either wold do a good job of flying that plane.

I finally got some plans for the extended Gee Bee, and that thing has a bigger fuselage than I remembered!  Is "Sunshine IV" still in flying trim?

Bill <><

[James Lee]

Bill
We were hoping to get to the KOI in January on our way to or from a Florida vacation, but I understand KOI will be in March right after VSC...   Bummer!!
The SunflyrIV is still flying, sorta energizer bunny....    Looking a bit tatty but the motor is running like a clock and I sure am familiar with that old dog!
Todd would enjoy a call...   He is putzing a bit with a couple of projects again, hopefully will get back to flying...   This work and family thing does get in the way!
You will enjoy the Gee Bee!  It is a rather challenging project....   I have started another one but it is stalled at this time...  Trying to figure out plans for  a PA version with one of the New Fox 60's...  Have some bench time on the motor and it seems to be a real horse!  Lew has some flying time on one and said it is very stout.
Later
Jim