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Author Topic: Fox 40 Stunt question for Fox engine SME  (Read 1286 times)

Offline YellowJacket

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Fox 40 Stunt question for Fox engine SME
« on: January 06, 2023, 10:58:35 PM »
can anyone please give me advice about this engine and my intention to use it in a Sig Super Chipmunk? I have always loved this plane and decided my building skills are now adequate enough to take it on.  The issue is that I thought I had an engine for it (Fox 40 Stunt I purchased from someone here) but I recently read that they could overheat inside a cowl and with a muffler.  I want to have a custom, long, tab muffler to funnel the exhaust out of the cowl so there is minimal material removal on that awesome cowl and burned castor won’t collect inside it.  However, I don’t want to have doubts about the motor after going to all that trouble if this statement is true..  Thoughts?

Greg

Online Brett Buck

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #1 on: January 06, 2023, 11:01:07 PM »
can anyone please give me advice about this engine and my intention to use it in a Sig Super Chipmunk? I have always loved this plane and decided my building skills are now adequate enough to take it on.  The issue is that I thought I had an engine for it (Fox 40 Stunt I purchased from someone here) but I recently read that they could overheat inside a cowl and with a muffler.  I want to have a custom, long, tab muffler to funnel the exhaust out of the cowl so there is minimal material removal on that awesome cowl and burned castor won’t collect inside it.  However, I don’t want to have doubts about the motor after going to all that trouble if this statement is true..  Thoughts?

Greg

     Which Fox 40?

      Brett

Offline GERALD WIMMER

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #2 on: January 07, 2023, 04:06:14 AM »
Hello I like the Fox 40 Deluxe Compact (the ABC not steel version) hope you have this one as this is the version I would be after.

The large frame 40 is heavy and the early versions of the Fox 40 are light but would need a strap on muffler and will tend to run hot with it.

Regards Gerald

Offline YellowJacket

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #3 on: January 07, 2023, 08:36:30 AM »
Hello I like the Fox 40 Deluxe Compact (the ABC not steel version) hope you have this one as this is the version I would be after.

The large frame 40 is heavy and the early versions of the Fox 40 are light but would need a strap on muffler and will tend to run hot with it.

Regards Gerald

Thank you Gerald!  Please see pic below and tell me what you see.  Based on your description and the price tag of $16.99 from the Hobby Hut being on the Fox box the 40 Stunt came in when it arrived, my guess it is the old style that you say will run hot with a muffler.  I also acquired an almost new looking 40 Fox a few years ago when I purchased the NVA version and it looks like an R/C version of the same motor.  I thought I would simply wire the carb open and use this on another plane (profile Broadak FW-190 I purchased a few years ago prior to me having to leave the hobby for a while) since it does not look like it can have a muffler of any kind with its "variable exhaust flap" installed (and does not look like it would be easy to remove and replace with a NVA).

If this is all true and I can only use these on profile stunters w/out muffler, can you please propose a suitable .35 - .40 motor for my Chipmunk that I can purchase used for a reasonable price and has longevity (please note I tend to build heavy for durability reasons)?

Kind Regards,

Greg
 

Online Ken Culbertson

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #4 on: January 07, 2023, 08:59:21 AM »
Thank you Gerald!  Please see pic below and tell me what you see.  Based on your description and the price tag of $16.99 from the Hobby Hut being on the Fox box the 40 Stunt came in when it arrived, my guess it is the old style that you say will run hot with a muffler.  I also acquired an almost new looking 40 Fox a few years ago when I purchased the NVA version and it looks like an R/C version of the same motor.  I thought I would simply wire the carb open and use this on another plane (profile Broadak FW-190 I purchased a few years ago prior to me having to leave the hobby for a while) since it does not look like it can have a muffler of any kind with its "variable exhaust flap" installed (and does not look like it would be easy to remove and replace with a NVA).

If this is all true and I can only use these on profile stunters w/out muffler, can you please propose a suitable .35 - .40 motor for my Chipmunk that I can purchase used for a reasonable price and has longevity (please note I tend to build heavy for durability reasons)?

Kind Regards,

Greg
 
Look for an OS40LA or 46LA.  Both are abundant and reasonably priced.  Keep in mind though that the Chipmunk (I had one using a McCoy 40) was designed for the "Fox 35" era when planes were very light.  There are some good modern .25's that would work but I have no experience with them.  I had a Fox 40 like the right one in your picture on a much larger plane.  The motor was pretty heavy and took more fuel and tail weight, but it did run well.

It is possible to remove the exhaust baffle and close the holes with a nut & bolt or heat resistant Epoxy then use a strap on. 

Ken
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Offline YellowJacket

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #5 on: January 07, 2023, 09:20:49 AM »
Look for an OS40LA or 46LA.  Both are abundant and reasonably priced.  Keep in mind though that the Chipmunk (I had one using a McCoy 40) was designed for the "Fox 35" era when planes were very light.  There are some good modern .25's that would work but I have no experience with them.  I had a Fox 40 like the right one in your picture on a much larger plane.  The motor was pretty heavy and took more fuel and tail weight, but it did run well.

It is possible to remove the exhaust baffle and close the holes with a nut & bolt or heat resistant Epoxy then use a strap on. 

Ken


Given I build heavy and plan to cover my Chipmunk with silk and plenty of dope to make her look pretty, would a K&B .40 be suitable with a long, tongue muffler?  I tried to buy one from MECOA a while back but they were backordered and no word on when they would be available.  I heard the break in was not bad at all with these.  Thoughts?


Offline Jim Svitko

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #6 on: January 07, 2023, 09:36:40 AM »
I will go along with Ken's suggestion.  Look for the 40LA or 46LA, preferably the 46.  If you build heavy, you will be glad you got the 46.  I have the 46LA on a 50 ounce Gieseke Nobler.  It is a nice combination, never lacking for power, and I can always use less nitro or different prop to slow the plane down if necessary.  And, the plane flies fine at that weight, no stalling in corners.

Another possibility is a Magnum 36, if you can find one.  It will easily power a plane of 48 ounces.  And, very fuel efficient, needing only three ounces of 5% nitro to finish the pattern with ease.  The Brodak 40 is also a good choice but good luck finding one these days.  I doubt if production will resume.

I would stick with a known engine, one that the rest of us have used, and have experience with.  They are out there, you have to be patient and search.  Swap meets might be a possibility to find something. 

Offline YellowJacket

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #7 on: January 07, 2023, 09:57:42 AM »
I will go along with Ken's suggestion.  Look for the 40LA or 46LA, preferably the 46.  If you build heavy, you will be glad you got the 46.  I have the 46LA on a 50 ounce Gieseke Nobler.  It is a nice combination, never lacking for power, and I can always use less nitro or different prop to slow the plane down if necessary.  And, the plane flies fine at that weight, no stalling in corners.

Another possibility is a Magnum 36, if you can find one.  It will easily power a plane of 48 ounces.  And, very fuel efficient, needing only three ounces of 5% nitro to finish the pattern with ease.  The Brodak 40 is also a good choice but good luck finding one these days.  I doubt if production will resume.

I would stick with a known engine, one that the rest of us have used, and have experience with.  They are out there, you have to be patient and search.  Swap meets might be a possibility to find something.


Thank you for the support on this.  I thought since I like to buy "made in America", I would spring for a new K&B at MECOA and help the company and our Hobby sustain interest.  But if they are not making good engines with all the consolidation and I should stick with searching for a used OS 46 LA, I will do that.

Do you or anyone else have a backstory on MECOA and what things look like for them?



Offline Jim Svitko

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #8 on: January 07, 2023, 10:07:07 AM »
I have never done any business with MECOA.  I hear things but I can't always verify what I hear.

At one time, they produced a 46.  Maybe they still do.  One guy I know got one.  He said it is an OK sport engine but not good enough for our purposes.  I will take his word for it since he is quite experienced at this and knows what he is talking about.

Try real hard to find a 46LA.  It will be worth the effort.  Trust us on this.

Offline Colin McRae

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #9 on: January 07, 2023, 10:49:53 AM »
You might also consider an Evolution 36NT. It is a BB engine and out-spins the OS 40 or 46 LA's. Plus, also a bit lighter. I have one on a Brodak P40 ARF. Great running engine in my opinion. And a tongue muffler is available for it if needed.
« Last Edit: January 09, 2023, 04:05:51 PM by Colin McRae »

Online Ken Culbertson

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #10 on: January 07, 2023, 11:26:19 AM »

I thought since I like to buy "made in America"

Problem is that unless you want to go with the high-priced Stunt engines which are really great but, you are in a very high price bracket because there just aren't many, if any, production engine manufacturers in the States and very few anywhere.  Buying used from "one of us" still keeps the $$ here even if the original came from the other side of the world.  If you want to buy new US you are probably going to have to go electric.  The buy in for all US Electric is around $300 which is less than a top end engine but still WAY more than a used, or even NIB from someone here.  Find that LA46.  We have several members here that probably have one or two that they can spare.  FYI the LA40 is not quite as good a stunt engine as the LA46 but still good.

Ken
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Offline GERALD WIMMER

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #11 on: January 07, 2023, 02:05:03 PM »
Hello I know the OS LA46 is a great engine but another overlooked engine made in the USA is the K&B45 Sportster. Admittedly a bit heavy but they give a really nice stunt run. The LA46 is very common and new parts still abound but if you want to be different there are a few other options out there but you need to be creative regards muffler types/weights and venturi sizes which complicates things.

Regards Gerald

Online Brett Buck

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #12 on: January 07, 2023, 02:18:11 PM »

If this is all true and I can only use these on profile stunters w/out muffler, can you please propose a suitable .35 - .40 motor for my Chipmunk that I can purchase used for a reasonable price and has longevity (please note I tend to build heavy for durability reasons)?

    That is the "Large Case" 40, it runs pretty well and would be a decent choice for the Chipmunk. You would want to adapt a muffler to it, I have seen several of them like that and they ran fine. Something like a ***stock*** 46LA would be a great improvement. Avoid heavy-duty engines, bearing in mind that this is really a 35-sized airplane, on the larger side, but still a mere 585 square inches and were flown with great success using Big Art OS35S.

    I would not see any need to beef up anything on the kit for durability, it is plenty strong enough as it comes. In fact, be careful about some of the wood selection because you might have some pretty heavy wood. Take particular care about the sheet wood, you don't have to go crazy about it but I have seen some of the kits where it was the consistency of oak.

     Brett
« Last Edit: January 07, 2023, 02:37:45 PM by Brett Buck »

Offline Dan McEntee

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #13 on: January 07, 2023, 07:36:17 PM »
   The one engine with the cast in venturi is the "custom" .40 stunt that Aldrich allegedly had some input on isn't it?? I have a few examples but have never run them. I think I have read on here that they run well with a nice sound, but are not a real power house. Back in my early years guys were putting ST.46's in them, but that engine choice doesn't help you much. If you could find one that some one had changed out the piston and liner for one of Brian Gardner's set ups, and it was a later one with muffler ears, that would put you in the ball park. I have seen guys drop ST G.51's in them also if they came out a bit heavy. I have been wanting to build another one with just that in it since I saw the first one like that. A G-.51 with a tongue muffler isn't all that heavy. There are worse put there. As far as the K&B.40, they seem to be tricky and you don't see a lot of guys running them n anything, primarily I think because they are heavy, big case engines. Even when the came out with a C/L specific ABC version, they didn't overwhelm the market, and I have yet to see one of those in a model also. The other Fox in the photo, is it marked that it's a .40??  When they came out with the .36X for the combat guys, Duke wanted to tap the R/C market, so in order to do that quickly, the first ones simply had the carb glued in with epoxy!! I actually know the guy that worked on that project!! He hangs  out on the combat forum here some times, Andre Ming. The late Lew Woolard did a good job with setting up the big case Fox .40s. I saw one of those fly a Jecto Shark build from the Jetco Kit at VSC one of the first times I went, and that was my introduction to Mr. Woolard!! I have flown Brodak .40s enough to know that I don't think I would put one in a Chipmunk. They can fly a 45 to 50 ounce profile model, but a draggy model like the Chipmunk, I just don't know Just finding something new out of the box will be difficult, with nothing in production right now, even the Brodak .40.
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Offline Dave Hull

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #14 on: January 07, 2023, 11:26:06 PM »
A former club member had a "banana" Skylark. It was probably straight, but he painted it yellow, using coat after coat of dope and it came out heavy. A large case Fox .40 hauled all 614 sq. inches around quite nicely. He was an intermediate level flyer, but the plane seemed to fly fine and the engine was easy to manage. I'd tell you what it weighed, but since it broke the club scales, we don't really know. The Skylark was cowled, had a muffler (I don't recall what kind) and I don't remember it overheating. Just try not to use a muffler that is overly restrictive.

As far as the R/C exhaust baffle case holes, you can turn that to your advantage if you can make a piece like they used on the Veco .19s years ago. Make a shaft that fits the holes, with caps if you can. Then drill and tap a hole in the center of it. Then file the rest of it down flat, maximizing the flow area thru the exhaust. That should work fine.

If you are looking for a K&B .40 for stunt, try to find one from the batch that Brodak ordered from MECOA and sold years ago. This should be the 99-4051. I don't know if the Brodak version had any other mods beyond what the 4051 has. (The basic 40xx series has been around since the 1970's.) With MECOA engines and parts, if it is in stock, I order it and they ship. If it is "in process," I move on to other sources because the odds are that it won't be available any time soon.

That said, they have another engine in this category that is interesting--and in stock--the MECOA .46 Control Line. It is a ball bearing ABC engine. You can see the specs at http://www.mecoa.com/mecoa/46us/4651.htm  I bought one to try out but have not run it yet. Nice looking and feels good. Pretty beefy at 11.2 oz compared to the OS 46LA at 9.6 oz, so likely not the best candidate for a Chipmunk!

The OS .46LA is going to be hard to beat in this size. I found the .40LA to work just fine also, although some guys say that it is not quite as tolerant in some setups. The .40 is slightly smoother running based on testing in a Cardinal profile with a very stiff kit-built nose.

Good luck with your search,

Dave

Offline YellowJacket

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #15 on: January 09, 2023, 10:08:12 AM »
Thank you all for your time in helping me!  The information provided is incredibly consistent, so I will be putting the Chipmunk build on a long hold until I come across a good OS 46 LA.

Best,

Greg

Online Dan Berry

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #16 on: January 10, 2023, 08:29:24 AM »
Thank you all for your time in helping me!  The information provided is incredibly consistent, so I will be putting the Chipmunk build on a long hold until I come across a good OS 46 LA.

Best,

Greg

You need to get to Scobee Field in Katy and you need to find Mark Troutman.  He's easy to spot at 6'8''.
He has a constant supply of engines and planes as well as help.
And you need an LA46 which isn't all that hard to find.

Online Ken Culbertson

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Re: Fox 40 Stunt question for Fox engine SME
« Reply #17 on: January 10, 2023, 05:04:51 PM »
Matt Colan has one for sale.

Ken
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