Author Topic: Fox .049's (Read 1446 times)

Dane Martin · « **on:** May 04, 2020, 05:09:39 PM »

I have been exchanging emails with Matt from EX models. He sent me some neat info regarding the fox .049. My initial question was, are there versions of the fox .049 where the exhaust isn't trapezoidal?

"Fox also made a basic 049 version which was not as powerful and used a single bypass cylinder with a more traditional exhaust setup.

The FAI was designed around free flight at the time, but was also used for C/L. I attached an article which details some differences between the two."

James Lee · « **Reply #1 on:** May 04, 2020, 07:07:01 PM »

Dane
the standard Fox 049 has an exhaust port very similar to the Cox Baby b, etc
Jim

Dane Martin · « **Reply #2 on:** May 04, 2020, 08:30:27 PM »

I have the standard then, Jim. I actually didn't know there was a standard. Haha.

kenneth cook · « **Reply #3 on:** May 05, 2020, 03:59:24 AM »

Dane, Bill Mohrbacher who recently left us has written a entire article on the Fox .049's. He was terrific on explaining differences and placing all of these engines in chronological order. The engine in your picture has a burnished mark on the side of the case where the name and designation has been ground off. These engines had the Comet logo on them used for the ready to fly Comet models. The venturi stack was also longer and squared off. Duke ground the logo off and cut the stacks on a angle not too mention cut the tank back off to utilize a backplate.

I get confused with this but the .07 I believe had 9 cooling fins and the .049 had 7 cooling fins. The .049 also has a bump on top of the piston crown whereas the .07 piston is totally flat. In addition, the flange where the the cylinder contacts the case is thicker on the .049 vs the .07.

Dane Martin · « **Reply #4 on:** May 05, 2020, 07:45:33 AM »

Wow, I actually know very little about fox engines. Especially these little ones. So.... I will look up Bill's write up. That is exactly the type of stuff I love to read.

Sounds like this one is possibly an .07? The glow head is bad. Complete open circuit. So I pulled it off and the piston is completely flat. I'll research more. I didn't even know they made an .07

kenneth cook · « **Reply #5 on:** May 05, 2020, 01:53:37 PM »

Dane, I had what I thought was a .07. I was with Bill this past November. Bill showed me that I owned a .049. My engine needed a piston. Bill put the engine together for me and installed new gaskets. It was neat the engine fired right up. I had this engine for 40 + years. I just thought it was neat for him to do that. Fox also made the Rocket .09, the .10 Hustler.

kenneth cook · « **Reply #6 on:** May 05, 2020, 02:00:44 PM »

Just so your aware, the glow plug is the same for both .049 and .07. The .07 isn't as common as the .049. You might just be surprised how this engine runs, I have both and I enjoy them for what they are. The Fox plugs can be real funny shutting off and running poorly. Just keep an eye on it. Matt from EX carries the plugs now. I've seen people drill for a standard plug on the existing head and have very good performance with this engine vs other head adapters where you lose performance.

Dane Martin · « **Reply #7 on:** May 05, 2020, 02:12:56 PM »

I may try to modify this bad one then. I'm actually filling my cart at ex models. Lol. I want the fai 049 for a free flight plane, and he has them. So I'll get a new engine and some parts!

Dennis Leonhardi · « **Reply #8 on:** May 10, 2020, 02:21:27 AM »

The Fox .049 FAI is a real screamer, very impressive in its day ...

Dennis

kenneth cook · « **Reply #9 on:** May 10, 2020, 06:05:22 AM »

If your interested, Matt from Ex Model Engines has purchased the last of the Fox FAI parts and has been able to complete them. Piston and cylinders are available as well as complete engines. he has also has had the ability to have the unfinished glow plugs completed and they're available as well. I commend his efforts .

Mike Scholtes · « **Reply #10 on:** May 11, 2020, 09:05:03 PM »

I have three of the Fox FAI .049 on various Nostalgia gas FF models, and they do indeed scream. Nothing like the "standard" Fox .049. Close to equal to the TeeDee .049, which I also have lots of on FF models. If you can get one or two (they're cheap), do it! Mine are run on bladder pressure, not sure if they would run on suction. This is too much engine for some of the early 1/2A FF models intended for OK or similar engines.

Dane Martin · « **Reply #11 on:** May 12, 2020, 01:54:41 PM »

Ken, I ordered a new FAI 049 and a replacement glo head for my .07 from Matt today.

Mike, I was thinking of putting the fai 049 on a zero. What do you think?

Mike Scholtes · « **Reply #12 on:** May 12, 2020, 02:39:36 PM »

Well, I have one on a Zero and it is more than enough engine. It's a relatively small Nos model with thin wing.

Mike Scholtes · « **Reply #13 on:** May 12, 2020, 03:37:03 PM »

Here is the FAI 049 on nose of Zero. Using backplate mount. Texas timers old-school mechanical DT timer/fuel pinchoff.

Andre Ming · « **Reply #14 on:** May 12, 2020, 03:41:12 PM »

Confession: Though I worked at Fox, I never saw an operating Fox .049. Sure wanted one, but never did get around to scrounging up the parts and fitting them/etc.

However, a friend that also worked at Fox long before, during, and after my years at Fox, told me the FAI .049 was indeed stout for its size. IF I'm recalling correctly, he indicated that most fliers tried to rev it like a TeeDee, but those that figured out it would swing a bigger prop than a TeeDee began to have the speed advantages over the TeeDee crowd using a prop that the FAI liked instead of trying to run it like a TeeDee.

Sorry, I can't remember what prop(s) he recommended.

Andre

Mike Scholtes · « **Reply #15 on:** May 12, 2020, 04:09:54 PM »

The APC 5.5 x 2.5 works well for me on smaller NOS models. Besides the Zero this includes the Geef 250 and T-Bird, all in 250 area. Not sure of actual RPM at launch, but it requires hearing protection. Not an issue with the new generation of e-power FF.

Actually I don't recommend the Zero. There are lots of other NOS models that are easier to trim and fly, especially the Starduster X. (Not strictly "Nos" but is generally allowed.) T-Bird is easy to fly. The new scaled-down Viking is also OK, but its another thin wing. I flew the original Viking in 1963 Nats. Still have it. If getting started in power FF I would go straight to E-36 and skip the nitro models. But it does sound like Dane has expert help available, so the Zero would be OK once past the first few test flights.

Dane Martin · « **Reply #16 on:** May 12, 2020, 04:43:45 PM »

Quote from: Mike Scholtes on May 12, 2020, 04:09:54 PM

But it does sound like Dane has expert help available, so the Zero would be OK once past the first few test flights.

There's a few notable fellows here that like to help. Jerry Hull has a zero. It's trimmed and flyable, although I forget what engine he has. I really like the way the zero looks, but I'll look into the others you've mentioned before deciding. I do like a starduster!

Andre Ming · « **Reply #17 on:** May 13, 2020, 08:04:51 AM »

Hi 'ya MM.

Like I said: Zero personal experience with the FAI.

I just pitched that out there as a "FWIW".

I would venture to say that Jay was likely talking about stock FAI's and a stock TeeDee's and not modified speed engines. I also haven't a clue what types of fuels were being refered to.

I did assemble a non-functional FAI (or regular .049?) and modified the head for a key loop and used it as a key fob for a few years. I may still have that "somewhere".

Andre

Andre Ming · « **Reply #18 on:** May 13, 2020, 08:21:12 AM »

Found it! In fact, walked over to the parts drawers and had it found within seconds. Wish my others stuff could be that organized!

Anyway, it's the worse for the wear after 50 years or so. I polished the case back then and had it shining like chrome, and the fins looked as if they were just machined. Time is tough on 'ya.

Andre

Dane Martin · « **Reply #19 on:** May 18, 2020, 07:05:37 PM »

I nearly cried today. I opened the mail and found this brand new tiny fox... it has been a great day

Dane Martin · « **Reply #20 on:** May 18, 2020, 07:05:59 PM »

Wayne Collier · « **Reply #21 on:** May 18, 2020, 08:19:08 PM »

Super Cool

Bill Adair · « **Reply #22 on:** May 18, 2020, 11:17:02 PM »

Dane,

I like the way mine runs, but it gave me absolute fits, until I found a tiny sliver of silicone fuel line inside the spray bar! Bought a few of these from Doug Martin many years ago, but have only run that problem engine.

Someone must have tried to seal the needle with fuel line, but ended up forcing too small a fuel line over the spray bar and shaved a sliver off the inside, and then must have forced the needle in far enough to start the threads and forced that sliver inside!!!

We tried everything, including blowing out the spray bar with compressed air a couple of times - all to no avail. Finally decided to check the position of the spray bar orifice by bending a thin wire with a right angle bend at the end and pushing it into the spray bar. Felt some resistance which was odd after all the soaking and blowing out, so I fished around until I hooked something. Pulled the sliver of silicone out after several tries and noted that it was the perfect size to hide from view but still free enough to move around with the engine running, causing erratic needle settings!

Good luck with yours.

Bill

Dane Martin · « **Reply #23 on:** May 18, 2020, 11:33:58 PM »

That would be odd, Bill! This one is all new construction, so fingers crossed...

Also, taking Ken's advice I drilled and tapped a blown glo head for a standard glo plug.

Dane Martin · « **Reply #24 on:** May 18, 2020, 11:35:03 PM »

Haven't actually run it yet, but it made good pops with the igniter clamp on.

kenneth cook · « **Reply #25 on:** May 19, 2020, 03:08:38 PM »

Dane, I'm very interested in how this new FAI version works. I never owned that version . I had a few conversations with Doug Martin who I believe provided these parts. He didn't have the resources or the money to have the unfinished engines completed. I believe Doug provided all the engines he could assemble with the parts and offered them through Henry Werner owner of Virginia Hobbysports. I think they're really neat engines. Scepter flight tests offers some good info on the characteristics of this engine. Ken

Bill Adair · « **Reply #26 on:** May 19, 2020, 05:38:48 PM »

Folks,

Checked one of my (never run by me) Fox .049 engines and found it is apparently an FAI model, though Doug labeled it Sport Model on the plastic bag. Inside was a second label that says intake .191" #11 drill, and .154" #23 drill. Venturi on the engine is the larger one, so at least the case is an FAI case. I seem to remember that Doug was out of FAI cylinders and used a standard cylinder on his .049 Sport models?

Dane, your engine has the FAI cylinder as trapazoid exhaust ports indicate.

Not sure our field at Delta Park is open now, as there are 3 new steel posts across the drive? When we find out why the Parks Dept put these posts across the road, and that the field is open to us again, I may get a chance to run this engine.

Bill

Dane Martin · « **Reply #27 on:** May 19, 2020, 05:55:07 PM »

Well going by that method, this FAI version I have is a number 13 bit , 0.185
And the less high performance looking fox .07 here is a 24 , 0.152

Bill Adair · « **Reply #28 on:** May 19, 2020, 08:10:50 PM »

Those variations are probably due to the not so smooth ID of the venturi? I had to wiggle my drills a bit to get the drills to slip inside. Seems the shanks get a little rough/dirty from use.

Just ordered one FAI 049 cylinder/piston from Matt, but can't find the Fox half-A engine article by Bill Mohrbacher? Anyone remember where that article was published?

Bill